Musculoskeletal pain is a major cause of work disability. Many patients with musculoskeletal pain seek care from health care providers other than their general practitioners, including a range of musculoskeletal practitioners. Therefore, these musculoskeletal practitioners may play a key role by engaging in sickness absence management and work disability prevention. This study aimed to determine the prevalence of musculoskeletal practitioners’ practice behaviours, and their perceptions and beliefs about sickness absence management by using Scandinavian chiropractors as an example, as well as to examine the association between these characteristics and two different practice behaviours.As part of a mixed-methods study, we surveyed members of the national chiropractic associations in Denmark, Norway, and Sweden in 2016. Descriptive statistics were used to describe prevalence. Multilevel logistic regression with backwards stepping was used to estimate odds ratios with 95% confidence intervals between each of the two practice behaviours and the characteristics.p = 0.007); and 86.5% of the Norwegian chiropractors always/often recommended to return-to-work versus 64.5 and 66.7% in Denmark and Sweden respectively (p < 0.001). In the final models, factors associated with the two practice behaviours were age, level of clinical experience, working as a teacher, the tendency to be updated on current legislations and policies using social services, contact with general practitioners, relevance of engagement in SAM, consideration of workplace factors, SAM as part of the clinical tool box, patient out-of-pocket fee, and recommending fast return-to-work.Out of the 802 respondents (response rate 56%), 372 were Danish, 349 Norwegian, and 81 Swedish. In Denmark and Norway, 38.7 and 37.8% always/often considered if sick leave was appropriate for their patient compared to 21.0% in Sweden  contains supplementary material, which is available to authorized users. Musculoskeletal pain is a major cause of work disability with socioeconomic consequences. Back pain-related disorders alone are enormously costly and are responsible for up to one quarter of days off from work. Across Scandinavia , 2, fourIn many parts of Europe, health reforms have focussed on shifting secondary care services into the community. However, the effort to reduce key cost drivers, such as second level diagnostic procedures and medical specialists, has resulted in a growing pressure on the general practitioners (GP) , 5. The This paper presents a cross-sectional, population-based survey, which is the second phase of a two-phased sequential, exploratory mixed-methods study. The first phase of the study involved a qualitative case study . The intIn the first phase, we found that the chiropractors’ practice behaviour was governed by the national legislations and policies of their respective countries. The rationale for engaging in SAM was related to the perceived level of competencies, an obligation to society, and to optimise favourable patient trajectories. For some chiropractors, SAM was highly integrated in their clinical care, but for others, it was not. The perceived barriers for engaging in SAM were related to patients’ and other stakeholders’ definition of the chiropractors’ scope of practice, patient out-of-pocket expenses, the administrative burden versus level of honorarium, and the lack of communication with other stakeholders.Building on this prior work, we sought to 1) determine the prevalence of musculoskeletal practitioners’ key practice behaviours, and perceptions and beliefs about SAM using Scandinavian chiropractors as an example, and 2) to determine what characteristics of the practitioners, practice behaviours, perceptions and beliefs, and country were associated with two different practice behaviours, i.e., how often the practitioner considers sick leave appropriate for the patient and how often the patient is recommended to return-to-work.SurveyExact. Two email reminders were sent to enhance the response rate . Further, social media outlets  were used to boost information about the study.We conducted a population-based, cross-sectional survey of all members of the national chiropractic organisations in Denmark, Norway, and Sweden. The national organisations cover 90–97% of all chiropractors in the three countries. Anonymised mailing lists were retrieved from the respective chiropractic organisations. By employing a series of screening questions, chiropractors were asked to complete the questionnaire if and only if, they were currently involved in patient management. Chiropractors were invited to participate via email in September 2016. A link in the email enabled the participant to directly access the survey using an online survey tool called In Denmark, the regional ethics committee of Southern Denmark gave approval for the study and declared that the study did not fall within the scope of the Medical Research Involving Human Subject Act (§14). The same conditions applied in Norway. Approval for data handling and storage covering both Denmark and Norway under the EEA-collaboration was granted from the Danish Data Protection agency. In Sweden, the regional ethics committee of Stockholm evaluated the project and found the study did not need ethical permission (advisory statement 2016/3:1).n = 5) of the researchers’ networks for comments. In order to obtain comments, a link to the pilot survey was also sent to three chiropractors with experience in SAM of musculoskeletal pain conditions (one in each of the countries). Finally, the survey was sent to the interview participants from phase one to determine whether the factors identified in the interview were satisfactorily represented in the survey.Potential items for inclusion in the survey were informed via the interviews from phase one. Four members of the research group drafted, discussed, and selected the final questions. The survey was developed in Danish and translated into Norwegian and Swedish by three bilingual members of the research team. To assess face and content validity, a draft survey was sent to members  or “Strongly agree” and “Agree” versus “Neither/nor,” “Disagree,” and “Strongly disagree” (perceptions and beliefs section) because of small cell sizes in some of the categories.The prevalence of the participants’ characteristics, practice behaviours, and perceptions and beliefs were described using frequencies and compared across countries using the Chi-squared test.consider sick leave appropriate); and 2) “How often do you recommend your patient to return-to-work rather than to stay at home?” where “always” or “often” were considered a positive outcome (recommend to return-to-work).Two outcomes were defined from the practice behaviour section; 1) “How often do you consider if sick leave is appropriate for your patient?” where “always” or “often” were considered a positive outcome .Associations were tested in a multilevel logistic regression analysis in a three-step approach. In step 1, the association between each of the outcomes and the independent candidate variables were tested in univariate logistic regression analyses. In case of an expected frequency below 5%, categories were collapsed with the nearest category. Results were expressed using odds ratios (OR) with 95% confidence intervals (CI). Candidate variables with n = 802). In Denmark, the response rate was 64.7% (n = 372), in Norway 53.4% (n = 349), and in Sweden 38.7% (n = 81). Twenty-eight respondents from Denmark did not see patients in the primary sector and were consequently excluded. The final number of respondents was therefore n = 774.The survey was issued to 1437 participants: 575 in Denmark, 653 in Norway, and 209 in Sweden. The overall response rate was 55.8% (p < 0.001), and the Norwegian population was relatively the youngest (p < 0.001) and had graduated more recently (p < 0.001). More Danish chiropractors graduated in Denmark compared to Norwegian chiropractors , whereas more Norwegian chiropractors graduated in the United Kingdom . In all three countries, the majority of respondents were owners of private clinics (p = 0.36).Characteristics of the 774 respondents are described in Table p = 0.007); and 86.5% of the Norwegian chiropractors always/often recommended to return-to-work versus 64.5 and 66.7% in Denmark and Sweden respectively (p < 0.001) . Forty-two percent strongly agreed/agreed that the GPs accept the sick leave certification rights of chiropractors, and 37.2% of the chiropractors agreed that GPs are helpful in sick leave reporting.consider if SL was appropriate at a p < 0.10 and were thus, included in the multivariable analysis. Three variables pertained to the participants’ characteristics ; 10 variables pertained to practice behaviour ; and nine variables pertained to the participants’ perceptions and beliefs .Based on the univariate analysis, 22 variables were associated with the outcome recommend to return-to-work, four variables pertaining to participants’ characteristics were associated with this outcome ; 13 variables associated with the outcome pertained to practice behaviour ; and four variables from the perceptions and beliefs block . In total, 21 variables were associated with this outcome.With respect to the outcome consider sick leave appropriate .In the final model of factors associated with the outcome te Table , particiRecommend to return-to-work  were more likely to recommend return-to-work, whereas those answering Age of 60+ years; Recommending fast return-to-work [agree or neutral/negative]) were less likely to recommend return-to-work. The amount of variance that was explained by country was 3.8% . The amount of variance that was explained by country was 3.8% .In the final model of factors associated with the outcome rk Table , particiThis study investigated the extent to which Scandinavian chiropractors currently engage in SAM with regards to musculoskeletal pain with their patients and evaluated their perceptions and beliefs about integration of work-related factors in their scope of SAM practice. Our data indicated that not all Scandinavian chiropractors engage in SAM, with less than 40% who would always/often consider if sick leave were appropriate for their patients, and 65–87% who always/often recommended their patients to return-to-work rather than to stay at home. However, and perhaps most interestingly, we observed that with chiropractors in Norway who have the right to prescribe sick leave, only about a third reported prescribing part-time sick leave, but they more often recommended their patients to return-to-work. In addition, the Norwegian chiropractors consistently reported more positive perceptions and beliefs towards SAM and a greater level of involvement with the process compared with the Danish and Swedish chiropractors.Given the different legislations regarding sickness certification rights, we forced country of practice into the analysis throughout, but the amount of variance in the final variable models explained by country was small. In a multivariable model, factors from three sectors: participants’ characteristics; practice behaviour; and perceptions and beliefs, influenced whether Scandinavian chiropractors considered sick leave appropriate for their patients and whether they recommend the patient to return-to-work. In the model of the outcome, “How often do you consider if sick leave is appropriate for your patient?” the strongest associations were found for strongly disagreeing with the statements, “Usually, it is not relevant to engage in my patients’ sick leave” (positive association) and “Recommendations regarding sick leave is a part of the clinical tool box” (negative association). In the model relating to the outcome, “How often do you recommend your patient to return-to-work rather than to stay at home,” the strongest associations were found for “working as a teacher” (positive association) and answering neither/nor to the statement, “It is important to recommend fast return-to-work” (negative association).Generally, we saw the highest proportion of SAM-supportive behaviour in Norway and the most positive perceptions and beliefs. Based on the findings in the qualitative part of this study , we beliOne characteristic, “Working as a teacher,” was retained in both multivariable models and was positively associated with the outcomes. Having more than 21 years of clinical experience and being older than 60 years of age were negatively associated with the outcomes, meaning that chiropractors with these characteristics were less likely to engage in SAM. These may be spurious findings, or they may be reflective of a generally different perception of the chiropractic scope of practice and patient management. Many of the teachers are employed by the universities and thus strongly influenced by evidence-based practice under the bio-psycho-social model. This may also be the case for the younger or more recent graduates. However, the design of the study did not allow us to explore these issues in detail.The integration of work-related factors in clinical practice has previously been investigated in Dutch and Canadian physiotherapists , 16. LikIn a study of Scandinavian GPs, no difference was found among Danish, Norwegian, and Swedish GPs’ decisions to grant sick leave when using case vignettes , and theIn the case of back pain, which lies within the chiropractors’ main scope of practice , 19, eviOur results indicate that the respondents often, and independently of country, considered work-related factors as part of their clinical assessment, but less than 40% of the chiropractors in all three countries always/often considered whether sick leave was appropriate for their patient, and fewer than 50% of the chiropractors made contact with the employer when discussing SAM. These are consistent with results from private musculoskeletal practitioners in the United Kingdom  where itWe surveyed the chiropractic population in three Scandinavian countries with a response rate between 39 and 65%. Due to the nature of the study, we do not have information about non-responders. However, the Danish and Norwegian samples were comparable to the respondents of national surveys of the profession regarding gender, age, and country of education. In Denmark, 77% responded to a 2014-survey . In NorwThe survey is limited to self-reported behaviour and to questions that imply some degree of generalisability across a variety of situations by using words such as “typically”. Self-reported behaviour may not necessarily reflect observed behaviour. Thus, the results of this study should only be interpreted as the practitioners’ self-reported practice behaviours under the given condition of a “typical” situation. The outcome measures and independent variables can be considered as proxy measures of behaviour. They may cover a range of constructs, and we were not able to assess how these items reflect objective measures of behaviour and practice.This study contributes with novel insights about practice behaviour, and perceptions and beliefs in a particular group of musculoskeletal practitioners (chiropractors). We have identified potential avenues for increasing the involvement of this group of practitioners in sickness absence management, such as the resources the chiropractors use to stay updated about musculoskeletal-related SAM, but also some of the system barriers for engagement. The results hold the potential to highlight important system and organisational strategies useful for informing policy and practice. Given the similarities of findings in studies of GPs and private musculoskeletal practitioners in the United Kingdom and the Netherlands, we cautiously believe the findings in this study may be generalisable to other groups of healthcare practitioners in similar settings. Healthcare practitioners, researchers, and policy makers who strive to test or implement strategies in relation to work disability prevention in clinical settings should be aware that practice behaviour is not only influenced by perceptions and beliefs, but also by organisational and system factors and are linked to legislation policies and financial schemes.Whilst not always engaged in sickness absence management with regards to musculoskeletal pain, chiropractors favour a ‘return-to-work’ rather than a ‘stay-at-home’ approach. Norwegian chiropractors who have the right to prescribe sick leave consistently report more positive perceptions and beliefs towards SAM and a greater level of involvement with the process compared with the Danish and Swedish chiropractors who do not have these rights. Several practice behaviours and perceptions and beliefs are associated with these outcomes; however, system or organisational barriers are linked to clinician non-engagement.Additional file 1:Survey of Scandinavian chiropractors, English version. (PDF 119 kb)


Moreover, these studies did not examine CSF tau levels in relation to cerebral glucose metabolism. We thus aimed to examine CSF tau measures, using both commercial and novel assays, in relation to [18F]THK5317 (tau) and [18F]FDG PET (glucose metabolism).Studies comparing CSF and PET tau biomarkers have included only commercial CSF assays examining specific phosphorylation sites  after 17 months. In addition to commercial assays, novel measures capturing N-terminus+mid-domain (tau N-Mid) and C-terminally truncated (tau-368) fragments were included.Fourteen Alzheimer’s disease (AD) patients  underwent [18F]FDG uptake, associations with baseline [18F]THK5317 uptake varied in relation to the degree of isocortical hypometabolism ([18F]FDG SUVR). Changes in the levels of the novel CSF markers tracked longitudinal changes in tracer uptake better than changes in P-tau181p and T-tau levels, and improved concordance with dichotomized regional [18F]THK5317 measures.While the levels of all forms of CSF tau were found to be inversely associated with baseline [181p and T-tau, tau-368 and tau N-Mid may better capture tau pathology and synaptic impairment.Our findings suggest that neurodegeneration may modulate the relationship between CSF and PET tau biomarkers, and that, by comparison to P-tauThe online version of this article (10.1007/s00259-018-4242-6) contains supplementary material, which is available to authorized users. Although many details surrounding the pathogenesis of Alzheimer’s disease (AD) remain unclear, a dominant viewpoint is that the dysmetabolism of amyloid-β (Aβ) initiates tau pathology that results in neurodegeneration and cognitive decline. Cerebrospinal fluid (CSF) measures of tau include phosphorylated tau (P-tau), an indicator of an abnormal state associated with the formation of neurofibrillary tangle (NFT) pathology, and total tau (T-tau), that reflects the intensity of axonal and neuronal damage . Recentl18F]flortaucipir (formerly known as [18F]T-807 and [18F]AV1451) [18F]flortaucipir uptake and CSF tau levels have shown modest positive correlations in cognitively unimpaired older adults and in patients with AD and non-AD neurodegenerative disorders [181p) and the mid-region of tau (i.e. T-tau) [18F]FDG PET, an important measure given evidence indicating that synaptic integrity mediates the impact of tau on cognition THK5317 [(S)-[18F]THK5117] [18F]FDG in a sample of patients with AD. Given findings suggesting that disease progression may be accompanied by a reduction in CSF tau [18F]THK5317 uptake. Further, in light of the likely future clinical use of tau imaging, we also aimed to examine the agreement between dichotomized CSF tau levels and [18F]THK5317 uptake.The aims of this study were thus to investigate the association between CSF tau levels, derived from both commercial assays (P-taud T-tau)  and noveTHK5117] –14 and THK5317 and [18F]FDG PET data were acquired in ten AD patients  after a median of 17 months  [18F]THK5317 and [18F]FDG PET studies were performed within 1.5 months (IQR 1–2.7 months) and follow-up studies within 0.5 months (IQR 0–1 months). CSF samples were collected approximately 24 months before the baseline [18F]THK5317 PET studies (IQR 14–34.5 months). Owing to outlying CSF tau values, one patient with AD dementia was only included in regression analyses involving CSF ratio measurements.Fourteen patients with AD , and nine cognitively unimpaired individuals  who had previously participated in baseline investigations were included , 17. Fol11C]Pittsburgh compound B [11C]PIB) scan [11C]PIB scan [11C]PIB-negative, and showed no differences in regional [18F]THK5317 binding as compared with young THK-controls.All patients had originally undergone clinical assessment at Theme Aging, Karolinska University Hospital, Stockholm, Sweden, and underwent follow-up, as detailed elsewhere . PatientIB) scan . PatientIB) scan  and showPIB scan . THK-con1-42/Aβ1-40, P-tau181p, and T-tau) CSF biomarkers within normal ranges. The CSF samples used were deidentified leftover aliquots from routine clinical analyses, following a procedure approved by the Ethics Committee of the University of Gothenburg (EPN 140811).Informed consent was obtained from all individual participants included in the study. Ethical approval was obtained from the Regional Human Ethics Committee of Stockholm and the Faculty of Medicine and Radiation Hazard Ethics Committee of Uppsala University Hospital, Uppsala, Sweden. A further 15 individuals were included as CSF biomarker-negative controls (CSF-controls); these were patients with minor cognitive complaints but with basic  and core , and a single molecule array (Simoa) method targeting a C-terminally truncated form of tau ending at amino acid 368 (tau-368) THK5317 PET studies were performed over 60 min following intravenous bolus injection of 217 ± 42 MBq. A static 15 min [18F]FDG scan was performed 30 min after injection of 3 MBq/kg. Baseline and follow-up images were coregistered to their respective T1-weighted MR images using PMOD v. 3.5 . In order to account for possible spillover effects from the white matter, MRI-based partial volume correction was applied to [18F]THK5317 PET images, as implemented in PMOD [Dynamic [ in PMOD .18F]THK5317 using the cerebellar cortex as the reference tissue [18F]FDG THK5317 [18F]THK5317 DVR and [18F]FDG SUVR were calculated as follows: /between-scan interval (years) THK5317  were als181p and T-tau values were classified as abnormal using cut-off values of >80 pg/mL and > 400 pg/mL, respectively THK5317 DVR cut-off values were defined using the mean plus two standard deviations of the DVR values in the THK-control group (elderly and young combined), in agreement with previous approaches for both tau [18F]THK5317 data, concordance using these measures was not investigated.CSF P-tauectively . Unpubliboth tau  and Aβ Pboth tau . Given tU test. To examine the relationship between regional PET ([18F]THK5317 DVR and [18F]FDG SUVR) and CSF measures, nonparametric rank-based estimation multilinear regression models were implemented [18F]THK5317 DVR, isocortical composite [18F]FDG SUVR, included as an interaction term with CSF tau, was binarized using a median value of 1.4. Simple slope analyses were used to assess multiple linear regression two-way interactions THK5317 and [18F]FDG uptake values, respectively  used in baseline [18F]THK5317 models was omitted to avoid overfitting, with rate of change values simply regressed onto CSF tau values, adjusting for covariates. For [18F]THK5317 uptake, P-tau181p levels were found to be associated with parietal rate of change, while tau N-Mid levels were associated with rates of change in parietal and Braak regions  use18F]THK5317 DVR cut-off values were as follows: 1.11 , 1.28 , 1.38 , 1.29 (posterior cingulate), 1.44 , 1.34 , 1.22 (Braak III/IV), and 1.33 (Braak V/VI). Concordance findings are summarized in Fig. 18F]THK5317 uptake and INNOTEST tau measures was approximately 50%. Although a similar level of concordance was reached when using tau N-Mid, agreement was substantially higher when using the tau-368/T-tau ratio (79%). When using INNOTEST measures and tau N-Mid, discordance was primarily in the form of isolated [18F]THK5317 PET positivity. Only isolated CSF positivity was found when using tau-368/T-tau. This pattern held when subgroups were examined separately, although concordance was higher overall in AD dementia patients than in those with prodromal AD . Two patients showed concordant positive profiles while two showed isolated [18F]THK5317 positivity. When considering all ROIs, no patients showed isolated CSF positivity. These cases are presented to highlight various CSF tau profiles in the context of high cortical tau burden.The following four cases illustrate differing biomarker profiles. For CSF, concordance with [18F]THK5317 uptake  and eight of nine ROIs (case 2) and temporoparietal hypometabolism at baseline. Using P-tau181p and T-tau, one patient (case 1) was concordant positive with the [18F]THK5317 findings, while the other (case 2) showed CSF tau concentrations below the cut-off values. One patient (case 1) showed increased [18F]THK5317 uptake, mainly in the temporal and parietal regions, with decreased [18F]FDG uptake in the lateral temporal cortex and the parietal cortex/posterior cingulate. The other patient (case 2) also showed increased [18F]THK5317 DVR in the medial parietal region, but with more widespread changes in metabolism, including in frontal areas. CSF tau N-Mid levels in the case 1 patient were nearly double those in the case 2 patient; tau ratios also showed a similar difference. Tau-368 levels, however, were similar. At clinical follow-up, the case 1 patient showed cognitive decline (in terms of MMSE score) and was diagnosed with AD dementia. In contrast, the case 2 patient showed relative cognitive stability and the diagnosis of prodromal AD was unchanged.The PET and CSF biomarker findings in two patients with prodromal AD are presented in Fig. 18F]THK5317 positivity. At baseline, both patients showed high uptake of [18F]THK5317 in cortical regions , and low [18F]FDG uptake in temporal, parietal and frontal regions. [18F]THK5317 uptake was higher at follow-up than at baseline in the frontal and parietal regions in both patients, with additional involvement of the temporal cortex in the case 3 patient. Both patients showed metabolic decline, predominantly in temporal areas. Large differences were seen in tau N-Mid and tau-368 levels and the tau-368/tau N-Mid ratio; however, both patients showed similar tau-368/T-tau ratios. No cognitive decline was seen in the case 3 patient at follow-up, while a decline in MMSE score of 2 points was seen in the case 4 patient.The PET and CSF biomarker findings in two patients with AD dementia are presented in Fig. 18F]FDG uptake, positive slopes, in line with the findings of previous studies, were found in those with more preserved glucose metabolism. This interaction with [18F]FDG uptake was observed for both established and novel CSF tau fragments. The levels of all forms of CSF tau investigated were found to be negatively associated with [18F]FDG SUVR.In this retrospective longitudinal study, the relationship between PET and CSF tau biomarkers was found to vary in relation to the degree of isocortical glucose metabolism. While a negative association was observed in those with more globally decreased [181p and T-tau levels may in fact reflect increased tau secretion resulting from the spread of AD-affected cells at risk of tangle pathology [18F]FDG PET. This scenario may explain the positive associations with [18F]THK5317 uptake at baseline observed in this study and in previous studies using [18F]flortaucipir THK5317 uptake, and between tau-368 ratios and the change in [18F]THK5317 uptake, lend support to this hypothesis.Given the unclear relationship between established CSF tau biomarkers and NFT burden , 33, incathology , with intaucipir –7. The itaucipir , have shtaucipir , 36–38. 18F]FDG uptake and CSF tau levels (P-tau181p and T-tau) in patients with AD have shown mixed results: although all have shown an inverse association, some have shown no significant association THK5317 DVR in the parietal lobe, with this pattern (i.e. CSF tau levels associated with baseline metabolism and the rate of change in [18F]THK5317 uptake in the same ROI) also observed for the tau-368/T-tau ratio , tau-368/tau N-Mid ratio  and, most strikingly, tau N-Mid levels (posterior cingulate and Braak composite regions). Together, these findings suggest a nonlinear relationship between the accumulation of AD-type PHF tau and neurodegeneration THK5317 uptake and CSF tau levels was somewhat lower, overall, than that found in the only other study so far to have examined concordance between tau biomarkers  [18F]THK5317 DVR were limited, this improved concordance, combined with the strong association between this measure and longitudinal increases in [18F]THK5317 retention, suggests that the tau-368/T-tau ratio may better reflect the shift between soluble and insoluble pools of tau than the single analytes  investigated. This would also probably hold true for tau-368 alone and as a ratio with tau N-Mid, although we were unable to directly test this in this study due the lack of a priori cut-off values or controls with both CSF and [18F]THK5317 PET data available.The level of agreement between dichotomized THK5317 positivity was the predominant finding for P-tau181p, T-tau and tau N-Mid. By contrast, only isolated CSF positivity was found using tau-368/T-tau. Possibly, the isolated [18F]THK5317 positivity may reflect a deceleration in neurodegeneration and/or the spread of NFT pathology, as previously described [18F]THK5317 DVR values. With regard to the cases presented, however, all four of the patients showed increases in [18F]THK5317 DVR and decreases in [18F]FDG SUVR, despite only the patients of cases 2 and 4 showing values below the thresholds for P-tau181p, T-tau and tau N-Mid. However, both these patients showed low baseline isocortical glucose metabolism. These observations, combined with our regression findings, suggest that tau biomarkers may initially follow an offset parallel upward course, followed by divergence, as CSF tau levels decline. Although this may indeed reflect the sequestration of tau fragments in NFTs, given the strong coupling between tangle pathology and neurodegeneration in AD THK5351 to monoamine oxidase B (MAO-B) [18F]THK5317, given results showing that despite a similar cortical laminar distribution, the MAO-B-specific tracer [3H]deprenyl and [3H]THK5117 do not compete at the concentration ranges used in PET studies [18F]THK5317 to PHF-tau. Further, longitudinal CSF sampling performed concurrently with PET studies would have allowed a better understanding of the trajectories of tau biomarkers, in particular whether a decline in CSF tau levels precedes increases in [18F]THK5317 retention. Lastly, partial volume correction of longitudinal data would ideally have been performed using MRI at follow-up. However, given the low rates of atrophy reported within isocortical regions over comparable time intervals THK5317 and [18F]FDG PET, and improved concordance with binarized [18F]THK5317 measurements. CSF and PET tau biomarkers, however, probably capture different aspects of tau pathology, similar to that proposed for CSF Aβ1–42 and amyloid PET [Although our findings are preliminary and subject to the above-mentioned caveats, they suggest that both positive and negative associations may exist between CSF and PET tau biomarkers, and that the directionality of their relationship may depend on the type of tau form measured, and/or an as-yet-unclear interplay between tau pathology and neurodegeneration. By comparison with P-tauloid PET .Online Resource 1(DOC 60 kb)Online Resource 2(DOC 469 kb)Online Resource 3(DOC 34 kb)Online Resource 4(DOC 32 kb)Online Resource 5(DOC 46 kb)Online Resource 6(DOC 220 kb)Online Resource 7(DOC 48 kb)Online Resource 8(DOC 46 kb)Online Resource 9(DOC 46 kb)Online Resource 10(DOC 37 kb)Online Resource 11(DOC 37 kb)Online Resource 12(DOC 37 kb)


In the United States, one out of every 500 African American children have sickle cell disease (SCD), and SCD affects approximately 100,000 Americans. Significant advances in the treatment of this monogenetic disorder have failed to substantially extend the life expectancy of adults with SCD over the past two decades. Hematopoietic stem cell transplantation (HSCT) remains the only curative option for patients with SCD. While human leukocyte antigen (HLA) matched sibling HSCT has been successful, its availability is extremely limited. This review summarizes various conditioning regimens that are currently available. We explore recent efforts to expand the availability of allogeneic HSCT, including matched unrelated, umbilical cord blood, and haploidentical stem cell sources. We consider the use of nonmyeloablative conditioning and haploidentical donor sources as emerging strategies to expand transplant availability, particularly for SCD patients with complications and comorbidities who can undergo neither matched related transplant nor myeloablative conditioning. Finally, we show that improved conditioning agents have improved success rates not only in the HLA-matched sibling setting but also alternative donor settings. Sickle cell disease (SCD) was first described by James Herrick, MD, in 1910 [In addition to both acute and chronic complications, SCD is associated with premature death. While there has been considerable improvement in median survival from 14.3 years in 1973 to about 45 years in 1994  [The first multicenter MAC human leukocyte antigen (HLA) matched sibling donor (MSD) HSCT report included 22 pediatric patients with symptomatic SCD and demonstrated that HSCT can cure SCD . Two patA more recent series of 87 pediatric patients examined results of related allogeneic HSCT after MAC in patients with a severe SCD phenotype . They reA 2017 survey included 1000 patients with SCD who underwent HLA-matched sibling HSCT between 1986 and 2013 and included data which were reported to international registries [Matched sibling HSCT with MAC is associated with high cure rates and low rates of graft rejection but is associated with an increased risk of organ toxicity, as well as delayed sequelae such as infertility and secondary malignancy. Reduced-intensity conditioning (RIC) has been associated with stable donor engraftment . In the While RIC protocols may spare toxicity, nonmyeloablative approaches employ increased immunosuppression (vs. myelosuppression), and therefore may further reduce sequelae and provide a curative treatment option for patients with increased comorbidities. We recently reported 67 patients who underwent nonmyeloablative HSCT; we had serially measured sickle hemoglobin (HbS) and percent donor chimerism levels and followed their clinical manifestations. Three patients whose donors had sickle cell trait had high donor myeloid chimerism (DMC) initially, but then slowly falling levels over time . As longNovel strategies to promote tolerance and stable mixed chimerism, as well as decrease GVHD, which is particularly important in the nonmalignant setting where there is no “graft-versus-sickle” effect, are expanding. Sirolimus’ mammalian target of rapamycin (mTOR) mechanism promotes tolerance by blocking T cell proliferation without inhibiting T cell receptor-induced activation . We prevThese results were duplicated at other institutions where DFS rates ranged from 91% to100% and no significant GVHD was reported. Thirteen high risk adults with SCD and a mean hematopoietic cell transplant comorbidity index of 3.3 underwent HSCT at the University of Chicago, Illinois . All patThese data suggest that 300 cGy TBI creates adequate space in the bone marrow to establish sufficient donor hematopoiesis to reverse the SCD phenotype. Alemtuzumab’s lymphocytotoxic effects endure for weeks after administration, thereby decreasing recipient lymphocytes and depleting donor alloreactive T cells after transplantation. These effects serve to promote tolerance and prevent GVHD. In addition to the previously described role of sirolimus in tolerance induction, it has a role in decreasing GVHD risk by promoting differentiation of regulatory and helper T cells .n = 102) had a 6/6 HLA-matched sibling and 17% (n = 50) of these were eligible for transplant [While HLA-matched sibling HSCT has demonstrated efficacy, the vast majority of SCD patients do not have an HLA-matched sibling . In a coansplant . Howeveransplant . In a coansplant . Thus, aCord blood (CB) is being used as an alternative source of hematopoietic cells for HSCT. Potential advantages of using hematopoietic stem cells from CB include a lower incidence of GVHD, its “off-the-shelf” availability, diminished risk of latent viral transmission, and negligible donor morbidity . While CResults from pediatric SCD patients who were treated by CB transplant (CBT) from a sibling donor and reported to the Eurocord registry revealed no TRM in two separate reports ,29. The Stable engraftment is possible with the administration of single CB units, particularly when cell dose parameters are applied. However, neutrophil and platelet recovery are delayed as compared with bone marrow transplantation (BMT), contributing to higher TRM due to infection and hemorrhage during the prolonged period of pancytopenia that follows CBT. Overall median time to neutrophil engraftment was 25 days; platelet reconstitution occurred at a median of 45 days in the related CB transplantation setting . Co-tran7/kg with a range of 2.1–6.3 [7/kg should be considered [Cord blood transplants from MSD, therefore, do not expand the donor pool. Historically, the results for unrelated CBT for SCD have been disappointing with high rates of graft rejection. The sickle cell unrelated donor transplant (SCURT) trial included a cohort of eight patients who received unrelated CBT. The conditioning regimen consisted of alemtuzumab, fludarabine, and melphalan with CSA or mycophenolate mofetil (MMF) and tacrolimus for GVHD prophylaxis. The OS was 88% but the DFS was only 38% and five of eight patients had graft rejection and autologous blood count recovery. Notably, the median post-thaw total nucleated cell dose was 4.5 × 10 2.1–6.3 . Ruggerinsidered . Enrolme7/kg . Toxicity and prolonged cytopenias remain a challenge for CBT from unrelated donors. Overall median time to neutrophil engraftment was 24 days; platelet reconstitution occurred at a median of 50 days for unrelated CB recipients , 22% mild cGVHD, and 11% chronic extensive GVHD . The medcipients . Table 2Matched unrelated donor (MUD) HSCT, where unrelated donor registries provide potential donor sources, is a viable alternative for patients who do not have an HLA-matched sibling. A National Marrow Donor Program search reported the highest probability of finding an optimal donor among whites of European descent (75%); black Americans of all ethnic backgrounds had among the lowest probability (16% to 19%) . As mostThe MUD arm of SCURT was a multicenter phase II trial whose aim was to utilize HLA-matched unrelated donors to expand the donor pool . The triA reduced toxicity preparative regimen of busulfan, fludarabine, and ATG was employed in five adolescent and young adult patients receiving MUD BMT. Four of five patients were alive and tree were free of SCD; a fourth patient was free of SCD after a second transplant. One patient developed grade 3 aGVHD and one developed severe cGVHD . These pHaploidentical donors are the most accessible donor population; almost everyone will have parents, children, and half-matched siblings who can serve as donors. Haploidentical HSCT affords the possibility of large cell doses, as well as the potential for repeat donor collections. Early studies demonstrated its potential to halt the progression of end organ damage: one long-term follow-up reported no patient with sustained engraftment exhibited any clinical signs of stroke or progression of prior cerebrovascular accident on imaging studies, no patient experienced change in cardiac shortening fraction, and all patients with avascular necrosis had stabilization of disease . The sigNumerous strategies have been employed to decrease the GVHD risk, including donor T-cell depletion and tolerance induction in host-reactive donor T cells . A murinPT-Cy has also proven efficacious in children and young adults with high risk hematologic malignancies receiving nonmyeloablative haploidentical HSCT. Forty patients ages one to 25 years received haploidentical transplants with GVHD prophylaxis consisting of PT-Cy, MMF, and tacrolimus . At six Several putative mechanisms for PT-Cy’s role in GVHD prevention have been suggested. Earlier work has suggested that although proliferating lymphocytes are depleted, there is relative resistance of T-regulatory cells to PT-Cy, which then mediate the anti-GVHD effects . Howevern = 5) had mixed chimerism and 75% of engrafted patients were able to wean off immunosuppressive therapy. None of the patients who received haploidentical grafts developed GVHD. This work reinforces the paradigm that limiting GVHD is usually associated with increasing mixed chimerism [The role of PT-Cy in the haploidentical setting was further explored in a cohort of 14 patients with severe hemoglobinopathies . The pathimerism . AchieviCo-stimulation blockade (COSBL) with CTLA4 immunoglobulin, for example abatacept, induces transplant tolerance and has been effectively employed as both GVHD prophylaxis and treatment . Indeed,We wanted to develop a regimen that was built from the success seen in the HLA-matched sibling setting with nonmyeloablative conditioning. We developed a regimen consisting of dose escalation of PT-Cy based on the results seen in our murine model where PT-Cy and sirolimus were synergistic in the lymphocyte replete setting, but in the lymphocyte deplete setting, PT-Cy did not improve donor chimerism levels . We tranAdditional up-front conditioning and T-cell depletion have improved the outcomes for haploidentical HSCT. A modified Hopkins regimen with 300 cGy (instead of 200 cGy) TBI and PBSC (in lieu of bone marrow) was employed in a cohort of eight SCD patients. The disease-free and overall survival were 75% and 87.5%, respectively. Two patients developed aGVHD and only one patient experienced cGVHD . AnotherEfforts at ex vivo T-cell depletion have employed CD3/CD19 or TCRαβ/CD19 reduction strategies. In a study of predominantly pediatric SCD patients  receiving CD3/CD19- or TCRαβ/CD19-depleted grafts, all patients had primary engraftment . AlthougNumerous transplant regimens and graft types have been employed. When combining all of the studies reported since 2017, the DFS for haploidentical transplant is 86%, while the overall survival is 93%. The DFS and OS from studies since 2018 alone improve to 91% and 94%, success rates which compare favorably with the HLA-matched sibling HSCT setting. These data suggest that haploidentical HSCT may offer a widely available curative strategy which is accessible even to patients with severe SCD manifestations. There are limited data comparing transplant outcomes for SCD by donor type. Our previous review reported the highest DFS (75%) in the MUD setting as compared with haploidentical (64%) and unrelated CBT (48%) . A 2019 With overall and DFS in excess of 90%, HLA-matched sibling HSCT is increasingly becoming the standard of care for patients with severe disease with evidence demonstrating that younger patients have improved DFS. In the HLA-matched sibling setting, myeloablative conditioning, including ATG to mitigate graft rejection, has high efficacy, although GVHD remains a significant source of morbidity. Nonmyeloablative conditioning aimed at tolerance induction spares toxicity and studies thus far have not reported GVHD in adults or children, despite the use of PBSCs. The availability of an HLA-MSD is limited, with as few as 7% of SCD patients identifying an unaffected matched sibling in one cohort . Therefo


Ever since the discovery of quasicrystals, periodic approximants of these aperiodic structures constitute a very useful experimental and theoretical device. Characterized by packing motifs typical for quasicrystals arranged in large unit cells, these approximants bridge the gap between periodic and aperiodic positional order. Here we propose a class of sequences of 2-D quasicrystals that consist of increasingly larger periodic domains and are marked by an ever more pronounced periodicity, thereby representing aperiodic approximants of a periodic crystal. Consisting of small and large triangles and rectangles, these tilings are based on the metallic means of multiples of 3, have a 6-fold rotational symmetry, and can be viewed as a projection of a non-cubic 4-D superspace lattice. Together with the non-metallic-mean three-tile hexagonal tilings, they provide a comprehensive theoretical framework for the complex structures seen, e.g., in some binary nanoparticles, oxide films, and intermetallic alloys. Quasicrystals differ from traditional incommensurate structures because they have non-crystallographic rotational symmetries. Here the authors introduce a scheme to produce metallic-mean quasicrystals in two dimensions with 6-fold rotational symmetry that can be seen as approximant to periodic tilings. In turn, the discovery of QCs offered a new perspective on complex crystalline lattices with large unit cells such as the Frank-Kasper phases3  and periodic crystals of large near-icosahedral clusters such as the Mackay icosahedra5, some of which were found to bear considerable similarity with QCs and are thus referred to as QC approximants7.The once-traditional understanding of positional order in condensed matter, which postulates translational periodicity, permits only 2-, 3-, 4-, and 6-fold rotational symmetry. In 1984, this view was challenged by the observation of an icosahedral symmetry in an Al-Mn alloy9. In experiments, they are typically seen at a somewhat different temperature, pressure, composition, etc. than QCs15 and they signal the proximity of QCs19, whereas theoretical studies of approximants allow one to explore structures that approach QCs in terms of both local arrangement of particles and material properties by using the mathematical apparatus developed for periodic crystals22. Approximants show that the simple, small-unit-cell periodic crystals and QCs are connected by a spectrum of structures that interpolate between the two extremes. This unified view of periodic crystals and QCs is further supported by the higher-dimensional analysis where both are seen as projections of a hyperdimensional lattice onto the physical space with rational and irrational tangents9.Approximants are among the cornerstones of QC science23 and originate in the bronze-mean tiling24  seen in the fundamental dodecagon of the bronze-mean tiling  and large (LT) equilateral triangles of edge length ing Fig. . In typekes Fig. . These t. m Fig. , or, equAs is common in self-similar patterns, the next-generation tiling can be obtained by magnifying the previous-generation tiling by a suitable factor and then placing the fundamental motifs at its vertices. Within the ST wedges of the next-generation tiling, the fundamental motifs partly overlap so as to create a gap-free pattern. On the other hand, the fundamental motifs fill out most but not all of the area of the previous-generation LT and R tiles.n = 3, m = 4 pattern. Upon subdivision, the two lengths of the i-th generation tiling Li and Si transform asψIA = nL/nS is ϕIA/n.Using this procedure, we find the subdivision scheme illustrated in Fig. n = 2k/3 − 1 and m = k − 2, then the inflation factor of this tiling equals the metallic meanx2 − kx − 1 = 0), where k is a multiple of 3. By locking n and m with these two relations, we obtain a subset of type IA patterns which is of particular interest due to the singular role of metallic means in QCs epitomized by the golden and the silver mean behind the Penrose29 and the Ammann–Beenker tiling31, respectively. In the metallic-mean type IA tilings, the length ratio readsk = 3 tiling, we have ϕ = ψ; for all other ks these ratios are different. Figure k = 6 type IA tiling, where k = 9 type IA and IB tilings, respectively, which provide an insight complementary to the complete flower-like patterns.If Type IA tiling is not the only 6-fold pattern that can be constructed using ST, LT, and R tiles. In type IB, the central LT rosette of the bronze-mean fundamental motif is enlarged so as to obtain a hexagonal patch of LT tiles with dge Fig. . This paβk for k is a multiple of 3. In a general two-parameter type IB tiling, the self-similar length ratio and the ratio of long and short edges are given by ψIB = kϕIB/3, respectively.The analysis of inflation in type IB tilings is analogous to that in type IA tilings. The transformation matrix in type IB counterpart of Eq.  reads7\dk is increased, they are dominated by ST and LT tiles, respectively, so that they approach a periodic hexagonal crystal ; the three additional k = 6 type I tilings are presented in Supplementary Note The most important feature of type IA and type IB patterns is that as tal Fig. . These ta and c rather than with a single one; in this respect, our analysis departs from existing constructions. We note that a generalization of the 6-D superspace representation of the bronze-mean hexagonal quasicrystal from ref. 24 is completely equivalent to the 4-D representation proposed below.To provide a theoretical basis for these tilings, we construct their higher-dimensional description based on a 4-D superspace lattice with two lattice constants e1, e2, e3, and e4, where ei ⋅ ej = δij and δij is the Kronecker delta. The points of the superspace lattice are given by nj are integers and the basis vectors aj read auj for odd j and by cuj for even j; uj constitute a direct sum of two hexagonal bases {u1, u3} ⊕ {u2, u4}:We denote the orthogonal basis vectors that generate the four-dimensional hyperspace by z = exp(iπ/6) of the T matrix are Suppose that the projected lattice allows a 30° rotation and scaling transformations: P∥2 = P∥. The complementary projection operator introduced by P⊥ = 1 − P∥ or, equivalently, by The projection operator onto the physical space is defined by P∥ and P⊥, we define the basis vectors in the physical and in the perpendicular space by x and y components of k = 3 tilings are shown in Fig. k = 6, 9, 12, and ∞ type IA and IB tilings are discussed in Supplementary Note Using entclass1pt{minimac/a so as to obtain a desired metallic-mean hexagonal QC. The simplest way of introducing the characteristic lengthscale ratio in the physical space and ensuring that the projection window is compact is to require that ϕIA and ψIA are given by Eqs. ,,\documenentclass1pt{minimanj are integers and ni also defines the position of the corresponding vertex in the perpendicular space k = 3, 6, 9, and 12 type IA and type IB tilings from Fig. Using these ratios, we now construct the projection windows in the perpendicular space. The position of a vertex of a tiling in the physical space is described by k = 3, 6, 9, and 12, with the intensities normalized by the central peak; the transforms of the k = 6 tilings are discussed in more detail in Supplementary Note k is increased the image clearly approaches the pattern characteristic for the hexagonal lattice, with the incommensurate peaks becoming ever smaller and ever closer to those representing the hexagonal lattice. The strongest peaks in k = 6, 9, and 12 type IA patterns have reciprocal-space vectors with indices , whereas the strongest peaks in k = 6, 9, and 12 type IB have reciprocal-space vectors with indices .Apart from their physical-space structure, the key signature of each of our metallic-mean tilings is its Fourier transform which captures the main features of its diffraction image (Methods). Figure 32, which gives rise to an incommensurately modulated periodic crystal if the period of the boundaries is not commensurate with that of the arrangement of atoms or other building blocks as appropriate8. With their characteristic structure consisting of domains forming a quasiperiodic pattern, our metallic-mean tilings can indeed be regarded as a special class of incommensurately modulated structures with an underlying periodic crystal and a set of modulation vectors from a quasicrystal with 6-fold symmetry.The hierarchical nature of the transforms with the prominent peaks and many smaller ones is rather evident, and the weaker peaks are consistent with the satellite reflections known from samples with a periodic arrangement of (anti)phase-domain boundariesks, these tilings are dominated by ST and LT tiles, respectively. By inspecting the patterns in Fig. i + 1)-th generation denoted by STi+1, LTi+1, and Ri+1, respectively, are related to those in the i-th generation byThe first-generation type IA and type IB sequences in Fig. k2 for large ks whereas the middle- and the bottom-row components scale as 1 and k, respectively. As a result, ST tiles quickly outnumber LT and R tiles upon inflation, their frequency approaching unity at large ks /I(0) = 1.0 for any q∥ which is characteristic of the periodic hexagonal lattice. Yet another indication of the convergence is provided by the four basis vectors of the physical space, which cease to be linearly independent as k → ∞ , six R tiles around them pointing in the radial direction, and six LT tiles filling the gaps between the R tiles. Upon inflation, this motif becomes decorated by smaller copies of itself rotated by 30° relative to the first-generation tiling; the orientation of the third-generation dodecagons is again the same as in the first generation  and n = m = 1 case shown in Fig. 33 but its square Like in type I tilings, we can construct generalized subdivision schemes for type II tilings parametrized by mentclass2pt{minimn between 1 and 5 and m between n and n + 6, which emphasizes that the multiple-of-3 metallic-mean tilings are just a small subset of the two-parameter ST/LT/R scheme; those for type IB and type IIA tilings are discussed in Supplementary Note n = 1, m = 2 type IA square-triangle pattern with the inflation factor of 36. Also intriguing are the generalized type IA and IB tilings with m = 3n/2 and m = 3n/2 are limit-periodic rather than aperiodic37. On the other hand, the k-uniform tilings that are not based on regular polygons30.Although the main emphasis of the above discussion was on the multiple-of-3 metallic-mean patterns, type II tilings show that the general two-parameter tiling scheme based on ST, LT, and R tiles is very rich, containing an infinite class of self-similar tilings of 6-fold rotational symmetry concisely represented by their inflation factors. In Table rs Table . As the mentclasspt{minima25, intermetallic alloys38, and oxide QC approximants39, which do contain such tiles. These experimentally observed structures are generally less neatly ordered than, e.g., the pattern in Fig. 40 whereby the periodic domains can either expand or shrink by collective displacement of a row of R tiles forming the twin boundary. The ensuing structures can thus be regarded as randomized versions of our QCs42. It is natural to wonder what may be the possible physical mechanisms behind the generally large distance between the domain/twin boundaries and the sophisticated patterns such as that in Fig. 27 suggests that the forces needed to stabilize such patterns need not be very complex, implying that they may well appear in an atomic or colloidal material even if it consists of a single type of particles.The hexagonal QCs based on ST, LT, and R tiles can be directly related to two-lengthscale superstructures seen in several systems including binary nanoparticlesThe late members of the multiple-of-3 metallic-mean self-similar hexagonal QCs described here approach the periodic hexagonal crystal; the non-metallic-mean QCs consisting of small and large triangles and rectangles must do so too. As such, these QCs can be regarded as aperiodic approximants of periodic crystals formed by increasing the size of their domains that consist of majority triangles, much like periodic approximants approach QCs as the size of their unit cells grows. We expect that there exist other types of aperiodic approximants with traditionally allowed rotational symmetry. For example, it is conceivable that 4-fold approximants may be derived from the Ammann–Beenker tiling by replacing the single-length square-rhombus tiling scheme by a two-lengthscale set of tiles including a small and large square and a parallelogram. Whether our approach can be used to construct approximants of QCs with a rotational symmetry that is coprime to any periodic crystal  remains an open question.43 which constitute the dodecagonal QC if the triangle-to-square ratio is k → ∞ but the domains form a regular hierarchical pattern. At the same time, we can draw an analogy between our aperiodic approximants and the well-known 1-D Fibonacci QCs44 based on the substitution rule A → AkB, B → A. These QCs can too be viewed as a simple type of sequence of aperiodic approximants because as k → ∞, the number ratio of the short and the long segments vanishes so that the Fibonacci QCs approach a 1-D periodic crystal. Together with the experimental indications mentioned above, these parallels support the notion of apeiodic approximants as incommensurately modulated structures characterized by locally periodic but globally quasiperiodic positional order.The aperiodic approximants proposed here resonate with two established concepts in QCs. Firstly, our hexagonal QCs can be likened to the random square-triangle tilingsk; at k = 6, there exist a total of five of them shown in Supplementary Fig. α, β, γ, and δ are positive integers. If this matrix is to define a subdivision rule, α must be larger than 1. The characteristic equation of the matrix is λ2 − (α + δ)λ + αδ − 3βγ = 0. If α + δ = k and αδ − 3βγ = −1, then the positive eigenvalue of the matrix, which represents the inflation factor, is the metallic mean βk. This shows that there exist several combinations of α, β, γ, and δ that lead to the same metallic-mean eigenvalue.Type IA and IB tilings do not exhaust the metallic-mean patterns at a given k = 3, the only choice of the four parameters consistent with the constraints is α = 2, β = 1, γ = 1, and δ = 1 but for k = 6 there are six combinations listed in Supplementary Table α and β. Two of them represent type IA and type IB tilings, which are elaborated in the main text, and the remaining four are described in Supplementary Note L/S defined by the eigenvector corresponding to the positive eigenvalue of the transformation matrix in Eq. -th generation tiling. The transformation matrix relating the tiling-vector indices of the i-th generation and the (i + 1)-st generation general type IA tiling parametrized by n and m isUpon inflation, i-th generation and the (i + 1)-st generation general type IB tiling parametrized by The transformation matrix relating the tiling-vector indices of the i-th generation tiling are denoted by STi,LTi, and Ri, respectively. We first spell out the recursive relation for a general type IA tiling parametrized by n and mTo compute the frequency of the majority tiles, we examine the numbers of ST, LT, and R tiles in type IA and type IB tilings; these numbers in the n = 2k/3 − 1 and m = k − 2,In the metallic-mean type IA tilings where k = 6, 9, and 12, respectively. As k → ∞, type IA tiling is evidently dominated by ST tiles as the majority tile as shown in Fig. k → ∞ are LT tiles as witnessed by the relative magnitude of entries in the top, middle, and bottom row of the matrix in Eq. 24) is \dq∥ such that aj ⋅ qj′ = 2πδjj', where δjj' is the Kronecker delta: qj are given by (2π/a)vj for odd j and by (2π/c)vj for even j, whereTo evaluate the Fourier transform of the metallic-mean tiling exactly, we first define the reciprocal-space basis vectors x(k) =  and q = : 1 = exp(iq ⋅ x(k)) = exp(iq∥ ⋅ x∥)exp(iq⊥ ⋅ x⊥). If the particles’ positions are described by δ-functions so that the density reads The following identity holds for any pair of vectors Supplementary Information


Astrocytic impairment is a pathologic feature of neuromyelitis optica spectrum disorder (NMOSD). S100B and glial fibrillary acidic protein (GFAP) are the two most commonly used astrocytic markers. The aim of this study was to evaluate whether CSF-S100B could serve as a marker of NMOSD. We enrolled 49 NMOSD patients , 12 multiple sclerosis (MS) patients, and 15 other noninflammatory neurological diseases (OND) patients. The CSF levels of S100B and GFAP were measured by ELISA. Both CSF-S100B and GFAP levels significantly discriminated NMOSD from MS  and OND . The CSF-S100B levels differentiated AQP4-Ab–positive NMOSD from MOG-Ab–positive NMOSD with higher accuracy than the CSF-GFAP levels . The CSF-S100B levels also significantly discriminated MOG-Ab–positive patients from seronegative patients (AUC = 0.848). Both CSF-S100B and GFAP levels were correlated with the Expanded Disability Status Scale (EDSS) during remission. Only the CSF-S100B levels were correlated with the CSF WBC count and the EDSS during attack. The levels of CSF-S100B seemed to have a longer lasting time than the levels of CSF-GFAP, which may benefit patients who present late. As a result, CSF-S100B might be a potential candidate biomarker for NMOSD in discriminating, evaluating severity, and predicting disability. Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing and often severely disabling autoimmune disease of the central nervous system (CNS), predominantly targeting the optic nerves and spinal cord . More thS100B and glial fibrillary acidic protein (GFAP) are two astrocytic markers often used to indicate astrocytic damage or dysfunction . In the Patients with NMOSD and MS were recruited from the Beijing Tiantan Hospital between March 2016 and September 2017. The NMOSD and MS diagnoses were made according to 2015 Revised International Criteria  and 2010The study was approved by the Ethics Committee of Beijing Tiantan Hospital affiliated with Capital Medical University, Beijing, China (No. KY2015-031-02), and written informed consent was obtained from all participants.The CSF samples were centrifuged, and the supernatants were collected and stored at −80°C until analysis. Positivity for AQP4-Ab and MOG-Ab was determined using the cell-based assay (CBA) with live HEK-293 cells transiently transfected with full-length M23-AQP4 or the plasmid containing full-length human MOG, as described previously , 12. The p value <0.05 was considered statistically significant.Statistical analysis was conducted using SPSS 22.0 . For comparison among groups, the categorical data were compared with Fisher's exact test. Continuous data were compared with the nonparametric Mann–Whitney U test with Bonferroni correction. A two-tailed Spearman's rank correlation coefficient was used to ascertain the associations. We judged correlations as strong when the correlation coefficients (r) were > 0.6. Receiver operating characteristic (ROC) curves were used to evaluate the discriminating values. The Youden index was calculated to determine the cutoff value. A two-tailedp < 0.001). Among the NMOSD patients, there was a significantly higher proportion of males in the MOG-Ab–positive group than the AQP4-Ab–positive group (p = 0.01), which was consistent with previous studies  were 684.1 (276.7-3124.3) pg/ml and 2.8 (2.3-88.3) ng/ml, respectively. Four patients had attack-related lesions in the cerebrum or brainstem without concomitant spinal cord lesions (2 MOG-Ab–positive NMOSD and 2 seronegative NMOSD). The levels of CSF-S100B and GFAP [median (range)] in these patients were 76.9 (65.1-100.3) pg/ml and 2.3 (2.3-2.4) ng/ml, respectively. The CSF-S100B and GFAP levels were higher in patients who had only spinal cord lesions than in those who had only cerebrum or brainstem lesions (GFAP is an intermediate filament protein, which is one of the key elements of the cytoskeleton of astrocytes , 17. S10Recent studies have shown that the CSF levels of GFAP were higher in NMO patients than in MS and OND patients. CSF-S100B levels showed a trend similar to that of GFAP levels but were less remarkable , 7. In lA total of 78-83% of NMOSD patients have AQP4-Ab . ApproxiFurthermore, in this study, we demonstrated for the first time that seronegative NMOSD patients had middle levels of S100B and GFAP Figures . Althoug ex vivo demyelinating model and EAE-induced rats, the inhibition of S100B action using an anti-S100B neutralizing antibody has been shown to reduce demyelination, downregulate the expression of inflammatory molecules and improve the clinical course of the disease [In terms of clinical relevance, the CSF-S100B levels showed a significant correlation with the CSF WBC count and the EDSS during attack and during remission. The CSF-GFAP levels were only weakly correlated with the EDSS during remission. This finding suggested that CSF-S100B might be a better tool than CSF-GFAP for assessing the inflammatory activity and clinical severity of NMOSD, which was different from a previous study by Takano et al. . The dif disease , 49. A r disease . The aboTo our knowledge, limited studies have focused on the correlations between CSF-GFAP and S100B levels in NMOSD patients , 7, and It was reported that the CSF-GFAP levels in NMOSD patients with only myelitis were higher than those in patients with only brain lesions . As mostSome limitations in our study need to be addressed. First, our patient cohort was small, especially the MS group, and derived from a single university hospital. Second, very few patients in our study had monoregional lesions, and no patients had only optic lesions. Third, as not all patients had full data sets of neuroimaging, we did not analyze the lesion load, which may lead to bias in our results. As a result, further studies will be needed to validate our findings in larger cohorts. More patients with monoregional lesions, including ON, should be analyzed to investigate the influence of attack-related lesion sites on CSF-S100B and GFAP levels. The association between the lesion load and the CSF-S100B and GFAP levels should also be evaluated.We present here for the first time a systematic comparative investigation of CSF-S100B and GFAP in NMOSD patients. Both the CSF-S100B and GFAP levels could discriminate NMOSD from MS and OND with high accuracy. However, the levels of CSF-S100B could distinguish AQP4-Ab–positive NMOSD from MOG-Ab–positive NMOSD with a higher accuracy than the GFAP levels and could also significantly discriminate MOG-Ab–positive patients from seronegative patients, while GFAP could not. Moreover, the CSF-S100B levels decreased more slowly and showed more clinical association than CSF-GFAP. Therefore, we suggest that although CSF-S100B lacks specificity compared with GFAP, it can still be used as a candidate tool for discriminating and evaluating NMOSD patients, especially for patients who present late after attack onsets.


After a first VTE and continuing TT, 11 thrombophilic cases had a second VTE despite adequate anticoagulation, 6 of whom, still anticoagulated, had a third VTE. The greatest density of thrombotic events was at three months after starting TT, with a rapid decline by 10 months. From <1 to 8 months after starting TT, 65% of VTE occurred, which may reflect TT-induced depletion of susceptible thrombophilic patients, leaving a winnowed residual group with fewer VTE events despite the continuation of TT. Before starting TT, we suggest screening for FVL, lipoprotein(a), and the lupus anticoagulant to identify patients at increased VTE risk, with an adverse risk-to-benefit ratio for TT. We suggest that TT should not be started in patients with known thrombophilia–hypofibrinolysis, and should not be continued after a first VTE. When TT is given to patients with thrombophilia–hypofibrinolysis, VTE may occur and then recur despite adequate anticoagulation.In our sequential studies of 67 and 21 patients, testosterone therapy (TT) interacted with thrombophilia–hypofibrinolysis, leading to venous thromboembolism (VTE). Compared to 111 VTE controls not taking TT (VTE-no TT), the 67 and 21 cases were more likely ( In June 2014, based on post-marketing surveillance reports including citation of some of our studies  added a VTE, particularly pulmonary embolism (PE), is associated with significant mortality risk , is a maThe sole currently available placebo-controlled clinical trial is the National Institutes of Health-supported prospective placebo-controlled Testosterone Trial of 790 men over age 65 with low serum testosterone levels (<275 ng/dL) and evidence of sexual dysfunction, physical dysfunction, or reduced vitality ,11,12,13Ultimately, the risk-to-benefit ratio of TT could optimally be explained by a placebo-controlled clinical trial comparable to the Women’s Health Initiative trials , which wOur studies of 67 and 21 patients with VTE after starting TT, and in 111 controls with VTE not taking TT (VTE-no TT), were carried out with signed informed consent, following protocols approved by our institutional Institutional Review Board IRB ,16, as wWe excluded from entry into the studies both TT patients and VTE-no TT controls whose VTE was provoked, associated with cancer, polycythemia vera, recent soft tissue trauma, bone fracture, hip-knee-foot surgery, airline flights >8 hours, or immobilization for >2 weeks. Hence, by selection, thrombotic events, both in TT cases and in VTE-no TT controls entered into the study, occurred spontaneously without superimposed acute triggering factors.The 88 patients and 111 VTE-no TT controls were studied in their serial order of referral over the past 4 years to our thrombosis center by their family physicians for evaluation of thrombophilia–hypofibrinolysis as a pathoetiology of their venous thrombotic events. TT had been prescribed by the referring physicians, and if not already stopped, it was discontinued by us before our assessment of thrombophilia–hypofibrinolysis. Measurements of thrombophilia–hypofibrinolysis were carried out at least 2 months after the cases’ initial thrombotic event.Because we did not initiate TT in the 88 TT-treated patients with VTE, we did not know the etiology of hypogonadism in the TT-treated group.Our studies of 88 patients with thrombotic events after starting TT along with 111 VTE-no TT controls represent a clinical case-control series examining interactions between TT and underlying familial and acquired thrombophilia–hypofibrinolysis in patients referred by virtue of unprovoked venous thrombotic events. These studies amplify findings from our earlier publication ,19. On a2 tests and by stepwise logistic regression after adjusting for age and gender.TT case versus VTE-no TT control comparisons of coagulation factors were made both by Mantel–Haenszel χIn the 88 patients and 111 VTE-no TT controls, laboratory assessment of thrombophilia–hypofibrinolysis included the following assays.PCR measures of thrombophilia  C677T/A198C) and hypofibrinolysis (plasminogen activator inhibitor (PAI-1 SERPINE 1) gene polymorphism 4G/5G) were performed in all cases and controls using previously published methods  by laborSerologic measures of thrombophilia included Factors VIII and XI, homocysteine, antigenic proteins antithrombin III, C, S, and free S, as well as the antiphospholipid antibody APL syndrome , the lupus anticoagulant, anti-beta2-glycoprotein). Established, previously published methods were used . High hoPlasminogen activator inhibitor-1 activity levels, associated with hypofibrinolysis, were not measured.In 2016 , we asseMean ± SD age was 57 ± 14 years. Testosterone gel (50 mg/day) was used by 58%, intramuscular T (150–200 mg/week) by 31%, human chorionic gonadotropin HCG by 2%, a patch by 3%, pellets by 4%, and clomiphene by 1%. Of the 67 patients, 70% had VTE , 24% had osteonecrosis, and 6% had ocular  thrombosis. Mean ± SD duration of testosterone therapy before the occurrence of a thrombotic event was a median of 6 months, a mean ± SD of 10.7 ± 13.3 months, and a 25th–75th percentile of 3–12 months .p = 0.038) and for the lupus anticoagulant (9/64 cases (14%) vs. 4/106 (4%) VTE-no TT controls, p = 0.019). Our findings that 24% of our TT-VTE patients had FVL heterogeneity versus 12% of our VTE-no TT controls emphasized the importance of FVL mutations for VTE 63] carri. Sharma , in a rep = 0.17).As emphasized by Corona et al. , there hIn a recent systemic review and meta-analysis of TT and VTE, Houghton et al.  concludeWithout large randomized trials of men, a “Men’s Health Initiative (MHI)” powered to assess the risk of cardiovascular disease, VTE, prostate cancer, and all-cause mortality of testosterone replacement therapy, there will be persistent controversy over whether TT is good, bad, or indeterminate. An optimal study, paralleling the Women’s Health Initiative WHI studies in women ,20, woulOur two recent studies of 88 patients (67  and 21  altogeth


Streptococcus suis and Escherichia coli for their susceptibility to cathelicidins in culture medium versus cerebrospinal fluid (CSF). Susceptibility testing was performed in analogy to the broth microdilution method described by the Clinical and Laboratory Standard Institute (CLSI) to determine minimum inhibitory concentrations (MICs) of antimicrobial agents. MICs were determined using cation-adjusted Mueller–Hinton broth (CA-MHB), lysogeny broth (LB), Roswell Park Memorial Institute medium (RPMI) or Dulbecco’s Modified Eagle’s Medium (DMEM) (the latter two supplemented with 5% CA-MHB or blood) and compared with MICs obtained in porcine or human CSF. Our data showed that MICs obtained in CA-MHB as recommended by CLSI do not reflect the MICs obtained in the physiological body fluid CSF. However, the MICs of clinical isolates of S. suis tested in RPMI medium supplemented with CA-MHB, were similar to those of the same strains tested in CSF. In contrast, the MICs in the human CSF for the tested E. coli K1 strain were higher compared to the RPMI medium and showed even higher values than in CA-MHB. This highlights the need for susceptibility testing of AMPs in a medium that closely mimics the clinically relevant conditions.Host defense peptides or antimicrobial peptides (AMPs), e.g., cathelicidins, have recently been discussed as a potential new treatment option against bacterial infections. To test the efficacy of AMPs, standardized methods that closely mimic the physiological conditions at the site of infection are still needed. The aim of our study was to test the meningitis-causing bacteria  The increase in antimicrobial resistance is an emerging problem and requires new strategies to combat bacterial infections . FightinAn important group of AMPs are the cathelicidins. They consist of 12–100 amino acids and occur in all vertebrate species  enriched with 10% lysogeny broth (LB) and found significantly lower MICs than in CA-MHB.In order to search for new therapeutic candidates and to test the efficacy of AMPs, standardized methods closely mimicking the physiological conditions at the site of infection are required. The Clinical and Laboratory Standard Institute (CLSI) recommendations for antimicrobial susceptibility testing  are follin broth . To deteIn this study, we determined MICs of meningitis pathogens for LL-37 and PR-39 using CA-MHB, LB, RPMI or Dulbecco’s Modified Eagle’s Medium (DMEM) media (the latter two supplemented with 5% CA-MHB or blood) and compared them with MIC values obtained in porcine or human CSF, too.E. coli strains, two S. suis strains and Staphylococcus aureus Newman Δdlt . The strains originated from the following sources:Five different bacterial strains were used: two different Escherichia coli K12 (serotype O rough:H48) typified by the National Reference Laboratory for Escherichia coli of the German Federal Institute for Risk Assessment (BfR). The avirulent and non-meningitic strain E. coli K12 is known to be susceptible to cathelicidins and served as a control ( control .Escherichia coli K1 (serotype O18:K1:H7) was originally isolated from the CSF of a child with neonatal meningitis  was used to generate growth curves and MIC values.The anonymized leftovers of CSF samples of patients receiving diagnostic lumbar punctures were pooled and utilized for the MIC determination. The patients did not suffer from any infectious disease and had no CSF pleocytosis. The non-commercial use of pooled CSF leftovers was approved by the Ethics Committee of the University Medical Center Göttingen, Georg-August-University Göttingen, Germany.Porcine CSF was taken from non-infected control animals of an animal experiment registered at the Lower Saxony State Office for Consumer Protection and Food Safety (LAVES) (Niedersächsisches Landesamt für Verbraucherschutz und Lebensmittelsicherheit) under no. 33.12-42502-04-12/0991.Human and porcine CSF were stored at −80°C.2 contents. AMP susceptibility testing was repeated for each different approach three times on independent occasions.Minimum inhibitory concentration values were determined via broth microdilution as described in the document VET01A4 of the Clinical and Laboratory Standards Institute . The metTM PB5008A) and incubated at 37°C overnight. Colony material was suspended in 0.9% NaCl-solution to an OD625nm of 0.08–0.13 corresponding to 1 × 108 CFU/mL. These suspensions were also used to assess the CFU/mL after sequential ten-fold dilutions in PBS to 10–5 and 10–6 and plating these dilutions on blood or LB agar plates  for counting the colonies.The strains were plated on blood agar plates . Growth controls (without peptide) and medium controls (without bacteria) were included.The bacterial suspension was diluted in the different test media by 1:100. Microtiter plates  were prepared with 50 μL test medium and AMPs in a two-fold dilution series. The concentrations of the AMPs per well ranged from 0.06 μg/mL to 128 μg/mL for LL-37 and up to 256 μg/mL for PR-39. Then, the prepared microtiter plates were inoculated with 50 μL bacterial suspension to yield a final concentration of the bacteria of 5 × 10The statistical analysis was performed using the Kruskal–Wallis test with the Dunn’s comparisons test being subsequently used for MIC testing in different media and atmospheres. The MIC values were analyzed with GraphPad Prism Version 8.0.1.The aim of our study was to test the MICs of LL-37 and PR-39 with broth microdilution in accordance with the CLSI recommendations  in CA-MH2+ concentration is approximate half of the serum concentration, i.e., corresponds to the fraction unbound in serum. The Mg2+ concentrations in normal CSF are slightly higher than the corresponding serum levels. When the blood CSF barrier is damaged as for example during active tuberculous meningitis, the Ca2+ concentrations only slightly rise and the Mg2+ concentrations only slightly decrease compared to the normal serum concentrations in contrast to the increasing protein content in the CSF of patients .MM, MK-B, NB, TG, JS, RN, CB, and SS designed the experiments. MM, LU, and MB performed the experiments. TG designed the peptides. MM, NB, and MK-B analyzed the data and drafted the manuscript. All authors proofread the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


To rationalize the selection of a research methodology, one must understand its philosophical origins and unique characteristics. This process can be challenging in the landscape of evolving qualitative methodologies. Grounded theory is a research methodology with a distinct history that has resulted in numerous approaches. Although the approaches have key similarities, they also have differing philosophical assumptions that influence the ways in which their methods are understood and implemented. The purpose of this discussion paper is to compare and contrast three widely used grounded theory approaches with key distinguishing characteristics, enabling a more thoughtful selection of approach. This work contributes to the existing literature through contrasting classic Glaserian grounded theory, Straussian grounded theory, and constructivist grounded theory in a systematic manner with prominent distinguishing characteristics developed from a review of the literature. These characteristics included historical development, philosophical perspective, role of the researcher, data analysis procedures, perspective of the grounded theory, and strengths/critique. Based on this analysis, three considerations are proposed to direct the methodological choice for a study: purpose, philosophy, and pragmatics. Understanding the similarities and differences in the grounded theory approaches can facilitate methodological transparency and determine the best fit for one's study and worldview as a researcher. Numerous scholars discuss the importance of choosing a research approach that is congruent with the researcher's personal beliefs  or believe that they should acknowledge and reflectively incorporate their previous knowledge and experiences into study procedures (SGT and CGT) (Breckenridge et al., There are pragmatic considerations that also influence the researcher's selection of a particular grounded theory approach. CGT and SGT procedures are more clearly defined than those of CGGT in the seminal texts and may be more user‐friendly for a novice researcher Cooney, . In addi5In the midst of continually evolving methodologies, it is crucial for researchers to be cognizant of the similarities and differences between the grounded theory approaches as they have significant implications for research procedures. This understanding facilitates methodological transparency Amsteus,  and phil


Tissue resident lymphocytes are present within many organs, and are presumably transferred at transplantation, but their impact on host immunity is unclear. Here, we examine whether transferred donor natural regulatory CD4 T cells (nT‐regs) inhibit host alloimmunity and prolong allograft survival. Transfer of donor‐strain lymphocytes was first assessed by identifying circulating donor‐derived CD4 T cells in 21 consecutive human lung transplant recipients, with 3 patterns of chimerism apparent: transient, intermediate, and persistent . The potential for transfer of donor nT‐regs was then confirmed by analysis of leukocyte filters recovered from ex vivo normothermic perfusion circuits of human kidneys retrieved for transplantation. Finally, in a murine model of cardiac allograft vasculopathy, depletion of donor CD4 nT‐regs before organ recovery resulted in markedly accelerated heart allograft rejection and augmented host effector antibody responses. Conversely, adoptive transfer or purified donor‐strain nT‐regs inhibited host humoral immunity and prolonged allograft survival, and more effectively so than following administration of recipient nT‐regs. In summary, following transplantation, passenger donor‐strain nT‐regs can inhibit host adaptive immune responses and prolong allograft survival. Isolated donor‐derived nT‐regs may hold potential as a cellular therapy to improve transplant outcomes. ANOVAanalysis of varianceAPCallophycocyaninCAVchronic allograft vasculopathyDMSOdimethyl sulfoxideEDTAethylenediaminetetraacetic acidEVGelastin van GiesonFCSfetal calf serumMSTmedian survival timenT‐regsnatural regulatory CD4 T cellsPBMCsperipheral blood mononuclear cellsPEphycoerythrinPBSphosphate‐buffered salineRT‐PCRreal time‐polymerase chain reactionSDstandard deviation1Although still considered a novel technology, ex vivo perfusion of recovered organs from deceased donors is likely to become widely adopted in the near future.We have recently reported that passenger T cells are present within human donor organs recovered for transplantation and, using murine transplant models, have demonstrated that donor T effector cells can augment host alloimmune responses directed against the allograft.22.1Following adult deceased‐donor lung or heart plus lung transplantation, blood from consenting recipients was sampled at predetermined time points  and donor CD4 T lymphocytes was identified by flow cytometry, on the basis of the expression of MHC alloantigen. Briefly, peripheral blood mononuclear cells (PBMCs) were labeled with anti‐CD3‐FITC  and anti‐CD4 PE  monoclonal antibodies  and with the relevant MHC class I HLA‐specific biotinylated antibody that were selected to bind exclusively to donor (but not recipient) HLA class I MHC alloantigen  Clinical Research Network Portfolio.2.2Kidneys underwent 1 hour of normothermic machine perfusion, as described previously,2.3b; B6) were purchased from Charles River Laboratories . Bm12 mice (B6(C)‐H2‐Ab1bm12/KhEgJ [H‐2bm12]) and H‐2b T cell receptor‐deficient mice  and an autoMACS separator (Miltenyi); cell purity  was analyzed by flow cytometry prior to injection.Recipient B6 mice were adoptively transferred by tail‐vein intravenous injection with 1 × 102.6Antinuclear autoantibody responses were determined by HEp‐2 indirect immunofluorescence  as described previously,2.7Cardiac allograft vasculopathy was assessed on elastin van Gieson –stained paraffin sections by morphometric analysis as described previously.2.8P < .05 were considered significant.Data were presented as mean ± standard deviation (SD) where appropriate. Mann‐Whitney tests were used for analysis of nonparametric data. Two‐way analysis of variance (ANOVA) was employed for comparison of antinuclear and anti‐vimentin autoantibody responses. Graft survival was depicted using Kaplan‐Meier analysis and groups compared by log‐rank (Mantel‐Cox) testing. Analysis was conducted using GraphPad 4 . Values of 33.1hi memory CD4 T cells, albeit samples from the same patient varied markedly at different time points, with no consistent phenotype observed. Notwithstanding, 3 different patterns of chimerism were evident  was also recovered  in this model is associated with the development of effector autoantibody responses that are triggered by graft‐versus‐host recognition of MHC class II on host B cells by passenger donor CD4 T lymphocytes.V Figure C, even fV Figure A. This s3.3In the preceding experiments, anti‐CD25 treatment of the recipient was continued after transplantation, raising the possibility that transferred donor T‐regs were also targeted. Notably, transplantation of heart allografts from donor bm12 mice that had received anti‐CD25 treatment before organ recovery also triggered markedly augmented autoantibody responses in WT C57BL/6 recipient mice, and heart allografts were rejected at least as rapidly as following recipient T‐reg depletion Figure A,B. To t4Our results demonstrate that following solid organ transplantation, donor‐derived CD4 T cells are released into the recipient circulation, and, at least following lung transplantation, may persist for some time. Within a larger population of conventional CD4 T effector cells, smaller numbers of regulatory T cells can be identified, and our murine studies confirm that these can inhibit host adaptive immune responses. These findings may hold particular pertinence to ex vivo organ perfusion strategies currently being developed; they highlight that rather than blanket depletion, preservation of select passenger lymphocyte subsets within the allograft may be beneficial.It is perhaps surprising that donor‐derived nT‐regs were more effective than recipient‐derived nT‐regs at blocking host humoral responses. Although the precise target epitopes remain ill‐defined,In addition to providing support for strategies that selectively retain donor T‐regs within the allograft, our results suggest that donor‐derived T‐regs may hold potential as a cellular therapy for prolonging allograft survival. This would differ from strategies that are currently under evaluation clinically, and that typically employ recipient‐derived CD4 T‐regs that are either polyclonal or exhibit direct allospecificity for the donor.TCR) genes,Tcrα and Tcrβ sequences first established by identifying dividing clones in standard mixed leukocyte reactions using third‐party cells as responders against recipient stimulators.Such a use of third‐party T‐regs to block host humoral alloimmunity would be distinctly different from proposed strategies that differentiate/expand T‐regs with self‐restricted specificity for alloantigen from the individual's endogenous T cell population,This approach may have wider uses beyond transplantation. It could, for example, be refined as a potential treatment for humoral autoimmunity, wherein nT‐regs from a third‐party donor that have direct‐pathway allospecificity for the individual's (recipient's) MHC class II antigens would be expected to block cognate interactions between autoreactive B and T helper cells in the host, thereby inhibiting autoantibody production.American Journal of Transplantation.The authors of this manuscript have no conflicts of interest to disclose as described by the  Click here for additional data file. Click here for additional data file.


Dear Editor,The identification of pathogenic bacteria facilitates better targeted treatments for bacterial meningitis (BM). However, early differentiation of Gram-positive and Gram-negative BM is a persisting challenge, especially in patients with empiric antibiotic pretreatment. Serum procalcitonin (PCT) was reported to be associated with Gram-negative bacterium in bloodstream infections . Our prep < 0.001) , serum PCT (b), CSF-CRP (c), serum PCT (d), CSF-leukocyte (e), and CSF-protein (f) in Gram-negative and Gram-positive BM. Table S1. Pathogens of patients with definite diagnoses of BM. Table S2. Type of BM. Table S3. Baseline characteristics. Table S4. Predictive performance of CSF-PCT in Gram-negative BM. (DOC 452 kb)