THE EXPERIENCE OF YOUNG HIV+ PEOPLE ATTENDING TRANSITION PREPARATION EVENTS: A QUALITATIVE INVESTIGATION

Keywords: young people, transition, group work, qualitative approach

Transition programmes which prepare young people with HIV to manage the medical, social and psychological consequences of the condition can provide clinical benefits for both young people and their families. The London based Looking Forward Project (LFP) is embedded within a National Health Service HIV family clinic. The project uses a group work approach and aims to equip HIV+ young people over the age of 12 years who know their status with the emotional, psychological and behavioural skills necessary to face the challenges of living with HIV. This small scale qualitative study investigated the experience of attendance, explored factors which facilitated participation in the groups and investigated the impact on their lives as a result of participation. Participants reported that the LFP events were educational but different to school-like activities, being with other young people reduced isolation and that receiving a voucher was an incentive to attend. Participation was facilitated through family support. Attendance at the LFP facilitated a positive attitude towards medication and hope for the future.

Introduction

HIV+ children and young people are living longer and healthier lives [START_REF] Prime | Decline in mortality in children with HIV in the UK and Ireland[END_REF]. HIV services face the challenge of developing transition mechanisms from paediatric to adult-centred care. Adult HIV services have little experience of dealing with the complex life issues that young people bring [START_REF] Miles | Transition from paediatric to adult services: experiences of HIV-positive adolescents[END_REF], parents of HIV+ young people have understandable concerns about their child's ability to cope with increased self-management, leakage of confidentiality, and HIV related stigma still exists [START_REF] Ostrom | The role of stigma in reasons for HIV disclosure and non-disclosure to children[END_REF][START_REF] Rotherham-Borus | Families living with HIV[END_REF][START_REF] Wilkins | Preparing HIV-positive young people for the challenges of adult life: a group work approach[END_REF]. These issues can make it difficult to achieve a planned transition process to facilitate good clinical outcomes.

The transition process

Transition is the "purposeful, planned movement of adolescents and young adults with chronic physical and medical conditions from child-centred to adult-oriented health care systems" (Blum et al, 1993: pp 570) and is a process not an administrative event [START_REF] Mcdonagh | The adolescent challenge[END_REF]. The transition process aims to help the young person acquire some of the emotional and psychological skills required to help them cope effectively with their condition over the course of their lives [START_REF] Weiner | Transition from a pediatric HIV intramural clinical research program to adolescent and adult community-based care services: Assessing transition readiness[END_REF][START_REF] Lewis-Gary | Transitioning to adult health care facilities for young adults with a chronic condition[END_REF][START_REF] Viner | Transition from paediatric to adult care: Bridging the gaps or passing the buck?[END_REF][START_REF] Uzoebo | Deconstructing youth transition to adulthood services: Lessons learned from the VISIONS program[END_REF][START_REF] Rosen | Transition from child-centred to adult health care for adolescents and young adults with chronic conditions. Position paper for the Society for Adolescent Medicine[END_REF].

There is evidence that good transition programmes can provide clinical benefits including improved follow-up [START_REF] Rettig | Adolescents with chronic disease: transition to adult health care[END_REF], better disease control and improved documentation of transitional issues [START_REF] Cameron | The continued care of children with renal disease into adult life[END_REF][START_REF] Robertson | Growing up and moving on. A multicentre UK audit of the transfer of adolescents with juvenile idiopathic arthritis from paediatric to adult centred care[END_REF]. Poorer clinical outcomes have been identified in other disease areas (e.g. diabetes, juvenile arthritis, cancer) where the process of transition was not emphasized including poorer out-patient clinic attendance, poorer adherence to treatment and increased morbidity and mortality [START_REF] Prime | Teenagers and HIV: What's the problem?[END_REF][START_REF] Martinez | Adherence to antiviral drug regimes in HIV-infected adolescent patients engaged in care in a comprehensive young adult clinic[END_REF][START_REF] Kipps | Current methods of transfer of young people with type 1 diabetes to adult services[END_REF][START_REF] Weiner | Transition from a pediatric HIV intramural clinical research program to adolescent and adult community-based care services: Assessing transition readiness[END_REF]. Within 3 the HIV context, however, psychosocial support and preparation for selfmanagement for HIV+ young people is rare [START_REF] Bitsindou | Need for dialogue in talking to children and adolescents living with HIV[END_REF][START_REF] Lesch | Paediatric HIV/AIDS disclosure: towards a developmental and process-oriented approach[END_REF].

In the UK there are 848 HIV+ young people aged between 10-18 years who are transitioning or will need preparation for transition. Of this number 611 receive their care in London (National Study of HIV in Pregnancy and Childhood, 2009) Family and cultural factors which may affect the transition process Most vertically acquired HIV+ young people in the United Kingdom (UK) are of African origin [START_REF] Judd | Morbidity, mortality, and response to treatment by children in the United Kingdom and Ireland with perinatally acquired HIV infection during 1996-2006: Planning for teenage and adult care[END_REF] and live in families which face multiple challenges e.g. immigration issues, housing, employment and educational difficulties, stigma and discrimination [START_REF] Green | The psychosocial and health care needs of HIVpositive people in the United Kingdom: a review[END_REF][START_REF] Waugh | Parental views on disclosure of diagnosis to their HIVpositive children[END_REF].

Many parents struggle with HIV disclosure to their children as they fear their children will be psychologically damaged by the news [START_REF] Waugh | Parental views on disclosure of diagnosis to their HIVpositive children[END_REF][START_REF] Weiner | Factors associated with disclosure of diagnosis to children with HIV/AIDS[END_REF][START_REF] Murphy | HIV-positive mothers' disclosure of their serostatus to their young children[END_REF]. As a result families may feel unable to take on new issues (e.g. transition issues) which are potentially distressing [START_REF] Wilkins | Preparing HIV-positive young people for the challenges of adult life: a group work approach[END_REF]. These factors may complicate the process of transition.

The Looking Forward Project

The London based Looking Forward Project (LFP) was created in 2004 and is embedded within a National Health Service HIV family clinic. The LFP provides a structured approach to transition in which topics such as medication adherence, romantic and sexual relationships and the development of coping strategies are addressed [START_REF] Wilkins | Preparing HIV-positive young people for the challenges of adult life: a group work approach[END_REF].

The LFP organises regular and structured events at four month intervals aimed at providing young people with both information about HIV issues and the opportunity to acquire new skills to manage difficulties and challenges.

Young people over 12 years who know their diagnosis are invited to attend The LFP is led by clinical psychologists and an HIV clinical nurse specialist but includes contributions from a specialist pharmacist, specialist midwife, a drama specialist and the local young peoples' sexual health team. Each group meets for one day three times yearly during holidays (e.g. Easter and summer holidays, October break) in a non-clinical environment (a church hall).

Participants are invited to lunch and also receive a £15 voucher at the end of the event. Questionnaire evaluation indicated that following attendance, knowledge levels about HIV increased as did levels of comfort in talking to health professionals [START_REF] Campbell | Group work with HIV+ teenagers to facilitate transition to adult services and avoid loss to follow -up[END_REF].

The project uses a group work approach in which different teaching and facilitation styles are employed depending on the issue e.g. teaching about medication uses both a didactic approach and a knowledge quiz in which misinformation is corrected and inadequate information is discussed more fully. Disclosure of HIV status to friends and romantic partners is addressed by using group discussion and drama techniques. Older members have led discussions about their experience of disclosure and younger members have had the opportunity to ask them questions about the experience. Sexual health needs are addressed e.g. demonstrations of condom and lubrication use, transmission of sexually transmitted infections is explored and discussed and participants practice placing condoms on plastic models.

Aims of the study

This small scale study aimed to investigate participants' experiences of the events, the factors which facilitated attendance and the impact on their lives as a result of participation using a qualitative thematic approach [START_REF] Braun | Using thematic analysis in psychology[END_REF]. To maximise study participation, participants were given a choice about how the interview was conducted i.e. by telephone or in person at their next clinic appointment. This recruitment approach was used as it was hard to agree with participants a time and venue to conduct the interviews because participants had competing demands on their time (e.g. homework, socialising, sport). No more than two months had elapsed between attendance at the event and study participation. The conversations were transcribed verbatim. Initially the transcripts were analysed separately by two authors (non-interviewers) for commonly recurring themes. These themes were then collaboratively reviewed and refined in line with guidelines described by [START_REF] Braun | Using thematic analysis in psychology[END_REF]. To ensure rigour and trustworthiness interviewer-debriefing took place, the themes were reviewed with the interviewers to ensure they were grounded in the data and the study design, interview items and findings were discussed with clinical colleagues.

Results

Themes were developed around the four main interview questions. With regard to information about the event and factors facilitating participation, themes which emerged were the importance and meaning of a personally addressed invitation, practical support, and the role played by the offer of lunch and a voucher as an incentive to attend. Themes which emerged from the question about their experiences of the events were that being with other young people was helpful but questions emerged which might not be raised in other settings (particularly about disclosure). In terms of the impact of attending, participants emphasised an increased acceptance of medication and that information and education helped in the coping process. They also expressed optimism for the future, although this was tempered with acknowledgement of challenges. Although the themes are presented as discrete entities it is important to note that there was overlap amongst them. (Max, 13).

Receiving lunch and vouchers encouraged attendance

Several participants were explicit that incentives played a key role in encouraging attendance. Three mentioned the importance of receiving a voucher at the end of the event, as well as lunch at a local restaurant. The lunch also offered a break from what could be an emotional experience, and taking lunch with the LFD facilitators also emphasized that the LFP was not like school. (John,15).

What was their experience of participation in the event?

Activities make the process interesting

The importance of activities was emphasised. Activities brought energy, fun and stimulated interest in what might otherwise be an unsettling experience.

"It was really good. I didn't expect it to be. I thought it would be just talking.

There was (sic) activities, acting, about HIV, Mum telling…That was kind of new" (Philip, 14)

The activities and games also differentiated the events from school experiences. The approach was a mixture of didactic teaching, questions were encouraged and participants were free to get snacks when they wished.

"I liked that you could just go and get a drink. It would have been like a school trip otherwise. They got to know us, not like teachers" (Philip,14).

Being with others who are the same is helpful

Participants remarked that it was helpful to be with other HIV+ young people.

Most participants mentioned that it was helpful being part of a group in which difficult explanations about status were not required and where there was no secrecy.

F

Focusing on HIV can be hard

Whilst participants found it helpful to be with other HIV+ young people, they sometimes found an explicit focus on HIV difficult. They tended to speak about their own and others' status in an oblique manner and often avoided using the term "HIV". This may indicate that there is a discomfort in naming the disease "I don't like talking about it (HIV)…it's hard" (Max, 13)

The complex issue of disclosure

Participants raised the complexities surrounding disclosure that they faced on a daily basis. In particular, they were concerned about the impact of the disclosure of their status on their romantic relationships. (Rita,14) Participants also talked about their fear of unintended/unwanted disclosure of their status, for example, when medications were taken in atypical environments.

"Just taking them and having to take them (meds) somewhere (stressed tone).

You What has been the impact on their lives as a result of attending?

Pro's and con's of taking medication

Taking medication was a major theme for participants. Several participants that as a result of attending they accepted that medication was a part of their lives and something they had to cope with. They felt that the educative aspect of the LFP helped them to understand the health benefits of medication, and tended to stress these rather than side-effects or adherence difficulties.

"I feel alright. I know I have to be careful and be healthy, but I have to live with it forever so need to just get on with it. I feel alright about taking medication as I know it's just something I have to do. I have to accept it and it's not too bad at the moment as I only to have to take three" (John, 15)

An uncertain but hopeful future

Participants had hope for the future even though some acknowledged that there might be difficulties especially in regard to disclosure of HIV status to romantic/sexual partners. This often overlapped with the theme of the importance of meeting other HIV+ young people to share experiences and being reassured that their experience was not unique.

Discussion

This small scale study focussed on factors that facilitated participation in the programme and the impact participation had on young peoples' lives. This is a small sample even for a qualitative study and consequently the results should be interpreted cautiously. However, both the project itself and the results have been encouraging both in the way participants have evaluated each event [START_REF] Campbell | Group work with HIV+ teenagers to facilitate transition to adult services and avoid loss to follow -up[END_REF] and the benefits they state they have derived from participation as reported in this paper. Reduced isolation and a stimulating fun space in which to address common issues emerged as important benefits for participants although they were well aware of the challenges they faced for the future particularly with regard to disclosure of HIV status. A balance of recognising that there will be challenges to face in life ahead and the ability to remain optimistic and hopeful seems to characterise many of the responses reported here. Indeed, the title of this study was inspired by this quote: "I look forward. I feel insecure but I am OK with it" (Philip,14).

It seems that receiving a personally addressed letter outlining the programme was important but participants also needed practical help from parents/guardians to attend. This may indicate that participants were more likely to come from families who are willing and able to support attendance both emotionally and practically. However, of the nineteen young people eligible to attend eleven actually did so. We do not know why the other eight eligible young people did not attend but it could be that they lived in families who were coping less well with HIV. All participants were ethnically African and many African families in London face challenges other than HIV [START_REF] Green | The psychosocial and health care needs of HIVpositive people in the United Kingdom: a review[END_REF] which may affect their capacity to identify with, and provide for the transition needs of their HIV+ young person. Parents may benefit from targeted therapeutic interventions to help develop their coping abilities both with regard to their own HIV issues and those of their HIV+ young people.

Further work may need to be developed within the family clinic to identify and support families who may be struggling. However, this would have to be balanced with families' right to privacy and respect for their wishes if they do not want their young person to participate. Alternatively, other eligible young people may not have attended as they and/or their families may have seen the events as less relevant to their personal circumstances or may have been concerned that attendance placed undue emphasis on HIV status rather than living a more "normal" life.

Participants indicated that the activities were an important component of the programme. differentiated the LFP events from school experiences and promoted an atmosphere that was collaborative, encouraging and enjoyable. Taking lunch at the local restaurant seemed an important incentive as was receiving a voucher at the end of the day. Participants understood the importance of taking their medication and generally emphasized the benefits rather than difficulties. However, taking medication may have also served to emphasize difference from family members or friends and increased concerns about unintended disclosure.

Being with others who were HIV+ was both comforting and difficult. It was reassuring to know there were others who shared similar experiences. Being open and not having secrets provided hope and fun. However, it could also be painful to talk about HIV especially in relation to potential romantic/sexual partners. All participants were at the age at which sex and sexuality were important issues and they were aware of the difficulties that disclosure of their status might pose to potential partners. Receiving positive, encouraging and normalising messages about their sexuality and sexual behaviour is important in order that positive young people do not grow up with negative feelings about themselves, sex and sexuality [START_REF] Fielden | Growing up: Perspectives of children, families and service providers regarding the needs of older children with perinatally-acquired HIV[END_REF][START_REF] Campbell | Sex, love and one-night stands: getting the relationship you want[END_REF]. Interestingly, participants did not comment on the specific sexual health components of the LFP which included experience of handling It may well be that older participants found this training to be more useful. However, participant embarrassment may also explain lack of reference to the LFP sexual health components as young people tend to be uncomfortable about such discussions with older people [START_REF] Burgess | Improving comfort about sex communication between parents and their adolescents: Practice-based research within a teen sexuality group[END_REF]. It may be useful to repeat this study in the future with a wider age range to assess the utility of these specific interventions.

Participants were a self-selected group and this may have biased responses.

However, six of eleven LFP attendees participated in the study which is a good response rate and lends reliability to the results. A larger sample would have addressed potential bias issues but because it was difficult to arrange suitable times and venue to conduct interviews it was not possible to recruit more participants within the study timeframe. It is also important to acknowledge the possible impact of interviewer bias as the interviews were conducted by two separate researchers.

Conclusion

The LFP will continue to develop and change in line with the needs of participants and this small scale study has provided some evidence that this is a useful approach to meet the transition needs of HIV+ young people.

However, the development of pre-and post-evaluation tools and a larger qualitative study focused on particular aspects of the project will be important to implement in order to further explore the effectiveness of the intervention.

  . In 2007 there were nineteen young people attending the family clinic who were eligible to participate. All were invited to each event.

  had attended an event in 2007 (n = 11) were sent a letter explaining that the LFP team wished to evaluate their experiences of the LFP. Six participants responded. Interviews were conducted by two interviewers unknown to the participants in order that as wide a range of responses as possible could be facilitated. Participants were interviewed once by a researcher.

  The interview schedule comprised four questions: How did participants learn about the event and what helped them to attend; what was their experience of participation in the event and what was the impact on their lives as a result of attending?

  three females participated in the evaluation. They ranged in age from 13-15 years. Demographic information is displayed in table 1. All participants were of African ethnicity and had acquired HIV vertically. All names are pseudonyms.

  and the need for supportReceiving a personally addressed invitation letter and event programme was identified as important by several participants and may have reflected a growing sense of independence and readiness to play a bigger part in their own health care. However, attendance at the event also required support and affirmation by family and/or health professionals and practical help e.g. dropping off the young person at the venue."I got a letter and there were instructions. I think I opened it, I'm not sure. I had heard about it before from Mum. I'm not sure how Mum heard about them. I decided to go. I got the bus and then got lost so I went home and Mum dropped me off. I never knew (name of venue) was in the centre (of town)"

  condoms and lubrication and the exploration of sexual negotiation strategies with potential partners. Perhaps participants were not sexually active at the time and sexual health training had reduced salience and applicability for

Table 1 Participant details

 1

	Name	Philip	Justine	Rita	Max	John	Ellen
	Gender	Male	Female	Female	Male	Male	Female
	Age	14	13	14	13	15	14

http://mc.manuscriptcentral.com/ac-phm-vcy Health Sciences

Acknowledgments

The authors wish to acknowledge and thank the young people who have participated in the LFP. We also wish to thank Dr Sue Abbott, Dr Neelam Dosanjh and Mr Ian McKay, Newham PCT, for their continued support of this project.


Dr Paolo Solla

Alessandro Vannelli

Alessandra Bolino

Giovanni Marrosu

Silvia Coviello

Maria Rita Murru

Stefania Tranquilli

Daniela Corongiu

Sara Benedetti

Maria Giovanna Marrosu

Heat shock protein 27 R127W mutation: evidence of a continuum between axonal CMT and distal HMN

Introduction. Heat shock protein 27 (HSP27), also known as HSPB1, belongs to the superfamily of small heat-shock proteins and is mainly implicated in the assembly of neurofilament network 1 . HSP27 mutations have been reported to cause both Charcot-Marie-Tooth disease (CMT) type 2F and distal hereditary motor neuropathy (dHMN) 1-6 , although never previously in a single family. The aim of this study was to divulge clinical and electrophysiological findings obtained in a single large Sardinian family bearing the HSP27 R127W mutation, revealing how affected subjects featured a marked interfamilial phenotypic heterogeneity varying from pure axonal CMT2F or dHMN phenotype, with one single patient clearly presenting associated features of spastic paraplegia.

Patients and methods. The index case, subject IV-2, a 44-year-old male, was investigated initially and his family tree is reported in Figure 1, clearly illustrating how other relatives were affected, leaning considerably in favor of an autosomal dominant means of inheritance. Divergent clinical features were observed in other affected family members. In spite of the index case featuring a marked association of spastic gait with peripheral neuropathy, pyramidal signs were virtually absent among the relatives, with predominant distal muscle weakness and wasting of the lower limbs, compatible with a diagnosis of peroneal muscular atrophy. Over the last three years, twenty-one members of this 5-generation Sardinian family have been studied, twenty of whom, including 13 members affected by peroneal muscular atrophy syndrome, have undergone screening for CMT2 mutations. Informed written consent was obtained from all participants.

Clinical and electrophysiological examination. Data collected included onset of symptoms, duration of disease, initial symptoms, disease course, presence of muscle cramps or pain, impairments (i.e., muscle weakness and sensory dysfunction) and other additional features. Twelve patients and 8 unaffected relatives were subjected to clinical examination and examined for: weakness and atrophy of the distal and/or proximal parts of the lower and upper limb muscles, deep tendon reflexes of the lower and upper limb muscles, presence of extensor plantar responses and Romberg sign, presence of foot and hand deformities, nerve hypertrophy and scoliosis. Vibration, touch, joint position and pinprick sensation were examined at various sites in the lower and upper limbs. In addition, the presence of tremor, trophic alterations of the feet and knees, cranial nerve abnormalities, involvement of vocal cords, ataxia, contractures, deafness, optic nerve atrophy, pyramidal signs, dysautonomia, and dementia was assessed. To determine disease severity in terms of ability to walk and run, each patient was assessed by means of the Functional Disability Scale (FDS) [START_REF] Birouk | Charcot-Marie-Tooth disease type 1A with 17p11.2 duplication. Clinical and electrophysiological phenotype study and factors influencing disease severity in 119 cases[END_REF] . A similar scale for the evaluation of a personal neurological disability affecting the upper limbs, with a six-point scale ranging from 0 to 5, was assessed and determined as follows: 0 = normal; 1 = normal but with cramps, 2 = fatigability in writing, 3 = handling difficult; 4 = need help to use hands; 5 = completely dependent. A standardized electrophysiological study was performed in eleven patients and six unaffected relatives. Motor nerve conduction velocities (MNCVs) and compound muscle action potentials (CMAPs) were investigated in the median and peroneal nerves. Antidromic sensory nerve conduction velocity (SNCV) and sensory nerve action potentials (SNAPs) were investigated in the median and in sural nerves. A concentric needle electromyography was performed using standard techniques. Data correlation tests were performed using Pearson's correlation coefficient or Spearman's rank correlations. Diagnoses of CMT and dHMN were made according to common diagnostic criteria [START_REF]for Charcot-Marie-Tooth Type 2 (CMT2-HMSN II) and Distal Hereditary Motor Neuropathy (distal HMN-Spinal CMT) 26-28 September 1997[END_REF] . Molecular genetic analysis. Genomic DNA was extracted from peripheral blood by standard methods.

A panel of 15 highly polymorphic STRs was used to exclude duplication or deletion of chromosome 17p11.2-p12 9 . The coding exons of mitofusin 2 (MFN2), myelin protein zero (MPZ), gap junction protein beta 1 (GJB1), neurofilament light polypeptide (NEFL), and ganglioside-induced differentiation-associated protein 1 (GDAP1) genes were analyzed by direct sequencing , with no mutations being revealed (Details of primer sequences used to amplify the MFN2, MPZ, GJB1, NEFL, and GDAP1 genes are available on request). In addition, only exon 3 of the Berardinelli-Seip congenital lypodystrophy-2 (BSCL2) gene was examined for the known Silver disease mutations, with the same result 10 (conditions available on request). Finally, to analyze HSPB1 coding sequence, exon 1, 2, and 3 were amplified using primers designed on flanking intronic sequences as follows: exon 1: forward ACGGGTCATTGCCATTAATAGAGACC and reverse AGAAGCGACCCGCACTCCCAATTC; exon 2: forward TGTTAATCCCTACCAGCCTGCAG and reverse, AGGCAAGCGTTACATTACACACCG; exon 3: forward ACGCGGAAATACACGTGAGTCCTGG and reverse TGCCTGAGGCTTCCTTCCACAAACACC.

PCR and sequencing reactions were performed under standard conditions. PCR purification was carried out using ExoSAP-IT (Amersham) whereas sequencing reactions using the BigDye v1.1 Terminator Cycle Sequencing Kit (Applera). Sequences were loaded onto a 3130XL Genetic Analyzer and analyzed using the Sequencing Analysis Software version 5.2.

Results. Among the twenty subjects of the family screened for CMT2 mutations, all 13 members considered as being clinically affected by peroneal muscular atrophy syndrome, proved heterozygous for the known HSP27 p. R127W mutation in exon 2. Neither of the other genes studied in these subjects revealed the presence of pathogenic mutations or polymorphisms. Furthermore, none of the 7 remaining unaffected relatives in our series harbored a mutation in exon 2 of HSP 27 gene. Clinical features of twelve patients are listed in table 1. The age at onset was clearly available for ten of the patients examined. Mean age at onset (± standard deviation) was 31.2±7.2 years (median 30, range 20 to 43). Two persons had onset at age 40 years or beyond. Mean age at investigation was 45.2±12.9 years (median 43, range 30 to 72), and mean disease duration at the time of investigation was 14±12.9 years (median 20, range 1 to 48). Course of the disease was slowly progressive in all patients. In five patients aged from 30 to 54 years, sensory examination was entirely normal revealing no deficits or abnormalities, while a further two other patients featured a very mild vibration sensory loss in the feet.

In the remaining 5 patients with sensory impairment, examination revealed a predominant loss of sensation in the legs, while in the arms mild subjective hypopallesthesia hypallesthesia was present in one patient. One patient alone presented total loss of sensation in the lower limbs. Clinical characteristics and sensory impairments were more pronounced with age. Involvement of vocal cords, contractures, deafness, optic nerve atrophy and dementia were not observed in any patients. With the exception of the index patient, no subjects presented bladder or sexual dysfunctions. Mean FDS (±DS) scored was 3±1.8; 4 with only a single patient confined to a wheelchair, likely reflecting a more severe impairment due to the longer duration of disease (48 years). , whilst mMean scores for neurological disability in the upper limbs was 1.8±1.7. No patients achieved a score of 5 (e.g. totally disabled).

Electrophysiological studies (Table 2) revealed a marked predominance of motor and sensory abnormalities in the legs. Peroneal CMAP amplitudes were generally reduced and were totally absent in four patients. In patients with no absence of peroneal CMAPs, MNCVs of this nerve were lower than 40 m/s but exceeded 38 m/s in three patents, and lower than 38 m/s in only one patient. Evaluation disclosed normal motor conduction studies of the median nerve in almost all patients, recording MNCVs of less than 38 m/s in only one patient, likely due (as the reduction in peroneal conduction velocity under 38 m/s in patient III5) to axonal loss with secondary demyelinating process. Sural SNAPs were absent in only two patients, although their amplitude was markedly reduced in a further three patients. Three of the remaining affected individuals displayed sural SNAPs within normal range, although closer to lower reference limits. Median nerve SNAPs were normal except for a slightly reduced amplitude in two patients. Statistical analysis showed that duration of disease correlates both with the Sural SNAPs Amplitudes (r= -.903; p<0.001) and Median SNAPs Amplitudes (r= -.669; p<0.05). According to the Classification and Diagnostic Guidelines for CMT2 and dHMN 8 , of the ten patients who had undergone both clinical and neurophysiological examination, five were diagnosed as CMT2, and a further two as dHMN (III:24 and IV:12) and a further t Two patients (IV:25 and IV:9 in whom clinical/electrophysiological findings (very slight reduction of vibration sensory loss in the feet but normal sensory nerve potentials at electrophysiological studies) were insufficient to warrant their inclusion in one of the above categories, were labeled as an intermediate type. In fact, in the latter two patients, clinical/electrophysiological findings (mild vibration sense loss in the feet but normal sensory nerve potentials at electrophysiological studies) were insufficient to warrant their clear inclusion in one of the above categories, owing to the fact that current classification requires the absence or presence of small sensory nerve action potentials as inclusion criteria for CMT2, but at the same time formulates the detection of impaired sensation as exclusion criteria for dHMN. Finally, due to the presence of spastic paraplegia, the index patient did not meet established criteria 8 for the diagnosis of CMT or dHMN. Indeed, these criteria 8 exclude patients with significant involvement of CNS, including pyramidal tract. In this patient, other differential diagnoses such as spinal cord compression; HTLV-1associated myelopathy or other disorders, were excluded.

Comment. We describe a large Sardinian family with predominant autosomal dominant axonal neuropathy in which a missense mutation (R127W) in the HSP20-α-crystallin domain of the gene encoding HSP27 was identified. The study of this large family allowed us to delineate the clinical spectrum, natural history and electrophysiological findings of this HSP27 mutation. To our knowledge, this is the first described family with HSP27 mutation where axonal CMT and dHMN were both present in different family members with a significant correlation between duration of disease and the occurrence of reduction of SNAP amplitudes, implying that sensory impairments may not be present in the initial stages of the disease, rather being manifested at a later stage. This point is of particular importance, demonstrating a difference in intensity rather than in nature between CMT2 and dHMN in the cases examined. Moreover, at least two members of the family studied here, diagnosed as affected by clear-cut CMT 2 forms, had previously been labeled as dHMN in the past, as provided for by standard criteria [START_REF]for Charcot-Marie-Tooth Type 2 (CMT2-HMSN II) and Distal Hereditary Motor Neuropathy (distal HMN-Spinal CMT) 26-28 September 1997[END_REF] . Furthermore, in several members of the large Sardinian family described in this paper, the clinical phenotype seemed to produce peculiar features not fully corresponding to either of the two forms, raising important questions concerning the specificity of criteria 8 that subdivide CMT from dHMN forms. To this regard, the exclusively motor involvement in dHMN is still a matter of debate due to minor sensory abnormalities being described elsewhere [START_REF] Irobi | Small heat-shock protein 22 mutated in autosomal dominant Charcot-Marie-Tooth disease type 2L[END_REF] . Compared with the only article 2 reporting the clinical features of seven Chinese patients with HSP27 R127W mutation, the present family was characterized by an earlier age at onset. In addition, while a mild to moderate sensory impairment of the hands was observed in all Chinese patients, this observation was not replicated in our study. Indeed, with one sole exception, none of our patients exhibited sensory abnormalities in the upper limbs. Bearing in mind the correlation between duration of disease and reduction of SNAP amplitudes both in the sural and median nerves, the latter findings can be easily explained by a higher age of Asian patients at examination (63,9±10,7) compared to that of Sardinian subjects (45,2±12,9). Mutations in another HSP (HSP22) 1112,12 13 may present both with CMT2 and dHMN phenotypes; likewise, mutations in glycil-tRNA synthetase gene have been reported to be associated with both diseases 13 diseases 14,1415 . Mechanisms whereby the same gene mutation is capable of causing different diseases remain unclear. On the grounds of the hypothesis that the primary pathologic process resides respectively only in the axons or in the neuron cell body, CMT 2 types are usually classified as axonal neuropathies (axonopathies) while dHMNs are considered as a separate entity and classified as motor neuronopathies, although considerable variations may occur 11 occur 12 . However, as our knowledge on gene mutations increases, growing evidence is accumulating to support the notion whereby a similar distinction between axonal CMT and dHMN is somewhat dogmatic. Our findings are suggestive of the existence of a continuum between the two entities, thus advocating a reconsideration of this strict pathonosological classification. The latter concept of a common spectrum is in full accordance with data reported by Irobi [START_REF] Irobi | Unraveling the genetics of distal hereditary motor neuronopathies[END_REF] Irobi 11 , underlining the arbitrary nature of the previously mentioned pathological dichotomization due to the fact that the clinical features manifested in dHMN are characterized by a well-established distal distribution indistinguishable from CMT2. Irobi not only suggests a major involvement of axonal sites in pathologic damage, but moreover observes how, owing to lack of autopsy studies, little is known about the status of the anterior horn motor neuron bodies 15 bodies 11 . An additional element of discussion is represented by the occurrence of spastic paraplegia in the index patient carrying the same HSP mutation. Although manifested infrequently, the presence of pyramidal features has been described in several patients with axonal form of CMT with variable severity ranging from hyperreflexia to overt spastic paraplegia. Dyck and Lambert 16 classified families affected by CMT with associated spastic paraplegia as hereditary motor and sensory neuropathy (HMNS) type V, while CMT patients plus mild pyramidal signs but without spastic paraplegia were labelled as peroneal muscular atrophy with pyramidal features by Harding and Thomas [START_REF] Harding | Peroneal muscular atrophy with pyramidal features[END_REF] . A systematic revision of case histories 18 has led to postulate that the presence of brisk reflexes in the legs and extensor plantar responses may be viewed as forming part of CMT2 phenotype.

The latter opinion would seem to be in agreement with findings obtained in the present study in which a patient with brisk knee reflexes was indeed observed. Recent observations indicate that CMT with pyramidal signs is genetically heterogeneous [START_REF] Zhu | Charcot-Marie-Tooth with pyramidal signs is genetically heterogeneous: families with and without MFN2 mutations[END_REF] and may be caused by mutations of at least two different genes: MFN2 [START_REF] Zhu | Charcot-Marie-Tooth with pyramidal signs is genetically heterogeneous: families with and without MFN2 mutations[END_REF] and N88S BSCL2 mutation [START_REF] Auer-Grumbach | Phenotypes of the N88S Berardinelli-Seip congenital lipodystrophy 2 mutation[END_REF] . Thus, although an isolated occurrence, the certain onset of spastic paraplegia associated with CMT form in the patient examined would seem to convey an additional feature of phenotypic variability in subjects with HSP27 mutations. However, the authors of the present study were not in a conclusive position to speculate whether this occurrence was specifically linked to the single mutation rather than to other epigenetic factors. Further studies should be performed with the aim of better defining this intriguing observation. To conclude, the findings obtained in the present study, broadening the spectrum of clinical manifestations of disorders associated with HSP27 mutations, support not only the hypothesis of a continuum between CMT2 and dHMN forms, but appear moreover to suggest a possible common spectrum between these entities and several forms of CMT plus pyramidal features (HMSN V), providing important implications for molecular genetic testing. Taken together, the data obtained suggest the need to provide for the establishing of more accurate and widely accepted working definitions to be applied in the case of CMT2/dHMN and the other CMT plus forms. These definitions should be based largely on clinical information and integrated with genetic data in order to further enhance the understanding of the pathological mechanisms involved and to provide for the development of targeted therapeutic interventions in the future.

Table 2 : Electrophysiological findings of Sardinian patients with the HSP27 mutation.

 2 : NV, normal value; SD, standard deviation, MNCV, Motor nerve conduction velocity; SNCV, Sensor nerve conduction velocity; ND, not determined; NS, Not studied; CMAP, compound muscle action potential; SNAP, sensory nerve action potentials; -, absent; ↓, reduced; LL, lower limb; UL, upper limb.

	Patient	Median nerve	Median nerve	Peroneal nerve	Sural nerve	EMG
		MNCV	CMAP	SNCV	SNAP	MNCV	CMAP	SNCV	SNAP
		(m/s)	(mV)	(m/s)	(μV)	(m/s)	(mV)	(m/s)	(μV)
	NV (SD)	48.8 (38)	6.9 (3.9)	56.2 (44)	39.0 (20)	48.3 (40)	5.1 (2.5)	52.5 (5.6)	18.9 (9.5)
	IV:2	58,3	8,9	63,4	22	39	2,9	50	2,8	LL chronic denervation
	IV:22	56,4	19,2	62,5	49,5	40,5	0,3	53,8	12,3	LL severe chronic denervation
	III:15	30,7	0,4	ND	5,2	39,3	0,7	ND	-	LL and UL severe chronic denervation
	IV:19	53,8	12,5	60,2	33,2	ND	-	29,8	0,61	LL severe chronic denervation
	IV:6	47,5	5,4	55,8	27,2	ND	-	32,9	3,8	LL severe chronic denervation
	III:24	51,1	6	59,7	40,7	39,5	0,3	41,2	9,6	LL chronic denervation
	IV:25	50,6	4,7	61,3	68,6	ND	-	51,9	9,7	LL severe chronic denervation
	IV:9	53,9	11,9	60,8	57,3	44,9	2,5	48,1	12,4	LL chronic denervation
	IV:12	58,8	13,1	71,2	54,5	43,1	3,7	45,3	16,3	LL chronic denervation
	III.9	46	↓	NS	NS	ND	-	NS	NS	LL severe chronic denervation
	III:5	NS	NS	ND	5	31	↓	ND	-	LL > UL severe chronic denervation

Abbreviations

FIGURE 1:

Pedigree of the family with HSP27 p. R127W mutation.

  Legend. Black symbols indicate affected family members; slash, deceased; circles, females; squares, males; *, genotyped individual; black arrows, subjects undergoing clinical and electrophysiological studies; white arrows, subjects studied clinically. Index patient -subject IV:2.

PtSex

Competing Interest: None declared.

Licence for Publication:

The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors an exclusive licence on a worldwide basis to the BMJ Publishing Group Ltdc to permit this article (if accepted) to be published in JNNP and any other BMJPGL products and sublicences such use and exploit all subsidiary rights, as set out in our licence.


Dr Fabiola Martin
email: f.martin@imperial.ac.uk

Alexandra Fedina

Silva Youshya

Graham P Taylor

A 15 year prospective longitudinal study of disease progression in patients with HTLV-1 associated myelopathy in the UK

published or not. The documents may come

A 15 year prospective longitudinal study of disease progression in patients with HTLV-1 associated myelopathy in the UK.

Background

HTLV-1 associated myelopathy (HAM) is a chronic non-remitting spastic paraparesis of insidious onset with lower limb weakness, spasticity and generalised hyperreflexia accompanied by bladder/bowel dysfunction and lower back pain in patients with positive HTLV-1 antibody. Cranial nerves and upper limbs are usually unaffected [START_REF] Cruickshank | Tropical spastic paraparesis and human T cell lymphotropic virus type 1 in the United Kingdom[END_REF][START_REF] Orland | Prevalence and clinical features of HTLV neurologic disease in the HTLV Outcomes Study[END_REF][START_REF] Franzoi | Disability profile of patients with HTLV-Iassociated myelopathy/tropical spastic paraparesis using the Functional Independence Measure (FIM)[END_REF][START_REF] Olindo | Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study[END_REF] . HTLV-1 infection is not a ubiquitous infection but endemic in the West Indies, Brazil, Japan, West Africa, Rumania and Iran [START_REF] Lee | HTLV-1 infection in Brazil[END_REF][START_REF] Moreira | Seroepidemiology of human T-cell lymphotropic virus type I/II in northeastern Brazil[END_REF][START_REF] Dos Santos | Seroprevalence of HIV, HTLV-I/II and other perinatally-transmitted pathogens in Salvador, Bahia[END_REF][START_REF] Sanders | The prevalence of antibodies to human T-lymphotropic virus type I in different population groups in Papua New Guinea[END_REF][START_REF] Safai | Prevalence of HTLV type I infection in Iran: a serological and genetic study[END_REF][START_REF] Abbaszadegan | Prevalence of human T-lymphotropic virus type 1 among blood donors from Mashhad, Iran[END_REF][START_REF] Necula | Screening for Anti-HTLV in Romania-1999 to 2005-Update[END_REF][START_REF] Gastaldello | Seroepidemiology of HTLV-I/II in Argentina: an overview[END_REF][START_REF] Sarkodie | Screening for viral markers in volunteer and replacement blood donors in West Africa[END_REF][START_REF] Murphy | Human T-lymphotropic virus type I (HTLV-I) seroprevalence in Jamaica. I. Demographic determinants[END_REF][START_REF] Mueller | Findings from the Miyazaki Cohort Study[END_REF][START_REF] Yamaguchi | Human T-lymphotropic virus type I in Japan[END_REF] .

WHO diagnostic criteria of HAM defining three levels of ascertainment for HAM diagnosis: definite, probable and possible, excluding all conditions that could mimic HAM [START_REF] Castro-Costa | Proposal for Diagnostic Criteria of Tropical Spastic Paraparesis/HTLV-I-Associated Myelopathy (TSP/HAM)[END_REF] , make geographically and genetically separate definite HAM cohorts comparable.

Studies of HAM prior to 1996 described progression during the first year followed by a plateau phase [START_REF] Araujo | Progression of neurological disability in HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP)[END_REF][START_REF] Roman | Tropical spastic paraparesis. A clinical study of 50 patients from Tumaco (Colombia) and review of the worldwide features of the syndrome[END_REF][START_REF] Vernant | Endemic tropical spastic paraparesis associated with human T-lymphotropic virus type I: a clinical and seroepidemiological study of 25 cases[END_REF][START_REF] Montgomery | Clinical and pathological observations on Jamaican neuropathy: a report on 206 cases[END_REF][START_REF] Cruickshank | Tropical spastic paraparesis and human T cell lymphotropic virus type 1 in the United Kingdom[END_REF] . Recent studies, in both Japanese and Afro-Caribbean cohorts, describe a more insidious onset with delayed diagnosis and continuous progression [START_REF] Matsuzaki | HTLV-I proviral load correlates with progression of motor disability in HAM/TSP: analysis of 239 HAM/TSP patients including 64 patients followed up for 10 years[END_REF][START_REF] Olindo | Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study[END_REF] . A more rapid onset and progression of HAM has been reported in patients transfused with HTLV-1 infected blood [START_REF] Nakagawa | HTLV-I-associated myelopathy: analysis of 213 patients based on clinical features and laboratory findings[END_REF] and in children [START_REF] Bittencourt | Manifestations of the human Tcell lymphotropic virus type I infection in childhood and adolescence[END_REF] . Non-or slow progressing patients with HAM have not been defined so far, although patients with stable HAM have been described previously.

A Japanese study of 64 patients with HAM followed up for 10 years, showed deterioration of gait, muscle power and bladder function in 56%, 41% remained unchanged and 3% of the patients improved. The rate of disease progression was associated with higher HTLV-1 viral load and older age of onset (>65years) as well as a history of blood transfusion. This study did not provide details of the presenting symptom, presence or absence of pain or bladder/bowel symptoms, walking aid usage at baseline, time to progression to additional aid or the mortality rate [START_REF] Matsuzaki | HTLV-I proviral load correlates with progression of motor disability in HAM/TSP: analysis of 239 HAM/TSP patients including 64 patients followed up for 10 years[END_REF] .

In 2006 a group in Martinique published longitudinal data on 123 Afro-Caribbean patients with HAM. The mean time from onset to first clinic visit was 5.3 years whilst the duration of HAM at final follow up was 13 years. At last review 81.3% had started using at least one walking stick, 56.9% two walking sticks whilst 36.6% had become wheelchair dependent, with median times from onset of HAM to the use of these aids of 6, 13 and 21 years respectively. Wheelchair usage started after 25 years of disease if the age of onset was <50 years but after only 14 years if age at onset was ≥ 50 years and this progression was significantly earlier in those patients with HTLV-1 viral load of >10 [START_REF] Lee | HTLV-1 infection in Brazil[END_REF] HTLV-1 DNA copies/10 6 PBMCs. Gender, history of blood transfusion and initial symptom (gait impairment v urinary disturbance) did not affect the disease course. The authors concluded that motor disability worsens throughout the disease course and that faster early deterioration predicts the rate of progression in the long-term [START_REF] Olindo | Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study[END_REF] . Of the 22 deaths (17.8%), 19 (86%) were attributed to HAM, with pneumonia and nephritis/sepsis as the dominant causes.

Two studies, from Brazil and Peru, have reported increased mortality in patients with rapid progression to immobility within two years of the onset of HAM [START_REF] Lima | Subacute progression of human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis[END_REF][START_REF] Gotuzzo | Clinical characteristics of patients in Peru with human T cell lymphotropic virus type 1-associated tropical spastic paraparesis[END_REF] .

In the UK, a HTLV non-endemic country, an estimated 20 000 persons are infected with HTLV-1 of which 3% will develop HTLV-1-associated myelopathy 30 . The majority of diagnosed patients are managed at the National Centre for Human Retrovirology.

The natural history of this unique cohort has not been described and may differ from other populations due to genetic, transmission and environmental factors. The aims of this prospective study were to describe the natural history and identify predictors of disease progression in this UK cohort of patients with HAM.

METHODS

Subjects and methods

For this observational natural history study, data were collected prospectively on all patients with HAM who attended the National Centre for Human Retrovirology (NCHR) in London from July 1993 to April 2007. Patients were followed up three monthly. Data were originally recorded in Excel and in addition all notes were hand searched for missing data. Patients were excluded if they were followed up for less than three months, had other confounding conditions or were co-infected with HIV. All comparisons are between the first and last clinic visits.

The descriptive variables were gender, ethnicity, perceived risk factor for HTLV-1 infection, first recalled symptom, age at onset, age at diagnosis of HTLV-1 infection or of HAM, duration of follow up and death.

The clinical variables were use of walking aids, localisation and severity of pain, bladder and bowel function. Measurement of timed walk was initiated in 2001, as the seconds (sec) a patient takes to walk 10 meters (m) with or without walking aid. Patients were categorised as using no aid (AID0), one walking stick (AID1), two walking sticks (AID2), a frame (AID3) or being wheelchair (AID4) dependent. Pain was categorised by presence, localisation and severity, which was scored by the patient using a 10 cm long visual analogue scale. Bladder hyperactivity was recorded as urinary frequency and urgency whilst urinary retention as the need for catheterisation. Bowel function was recorded as normal, mild (>3/week), moderate (1-3/ week) and severe (< 1/week) constipation. Data were collected on all symptomatic and potentially disease-modifying therapy given. Zidovudine and lamivudine were prescribed within a randomised controlled trial which is published [START_REF] Taylor | Zidovudine plus lamivudine in Human T-Lymphotropic Virus type-I-associated myelopathy: a randomised trial[END_REF] ,and ciclosporin was prescribed within an ongoing clinical trial during data collection for this study.

HTLV-1 viral loads, (HTLV-1 DNA copies/100 peripheral blood mononuclear cells [PBMCs]) quantified by 'in house' real-time PCR using the Roche LightCycler (Roche, Mannheim, Germany), were assayed prospectively [START_REF] Goon | HTLV-I specific CD4+ T cells: Immunodominance hierarchy and preferential infection with HTLV-I[END_REF] .

Statistical Analysis

Data were analysed in SPSS-14 through parametric (t-test) and non- Results were assumed statistically significant and the null hypothesis was rejected if a p value < 0.05 was achieved.

Results

Of the 55 patients with HAM, 48 were included in the analysis. Seven patients were excluded, five because of insufficient data, one patient had polymyositis and one HIV-1 co-infection.

Table 1 gives an overview on demographics, patients age of onset and follow up as well a summary of disease modifying and palliative medication prescribed at first visit. Patients were mostly female, of Afro-Caribbean origin, and reported mother-to-child transmission and/or unprotected sexual intercourse with a person from an endemic region as the most likely route of HTLV-1 acquisition. Four patients (8.3%) cited blood transfusion before 2002, when obligatory screening for HTLV-1/2 antibodies was implemented in the UK, as their sole risk.

The most common first symptom was unilateral leg weakness at a median age of 48 years. Five (10.4%) patients were diagnosed with HTLV-1 infection prior to developing HAM, one of whom developed HAM during follow up. In this sub-group the median time from diagnosis of HTLV-1 infection to onset of disease was 1.2 years. Median follow up was 3.8 years resulting in 212 person-years (py) of follow up. Oral prednisolone, zidovudine, lamivudine, methotrexate and ciclosporin were prescribed as disease modifying drugs during follow up.

Time to first use of a walking aid

At the baseline visit 38 (79%) patients were walking compared to 32 (68%) patients at last clinic visit (p= 0.25). At baseline 13 (27%) patients were walking unaided (AID0), 25 (52%) were using walking aids (AID1, 2 and 3), eight (17%) were wheelchair dependent (AID4) and two (4%) were bed bound. During follow up 19 (54%) patients needed additional aid: seven patients progressed to AID1, three to AID2, three to AID3 and six to AID4. The median times from onset of HAM to AID1, AID 2, AID 3 and AID4 were 11 (range 0.8-24.5, 95% CI 2.8-17.30 [CI]), 11.2 (range 6.4-16.5, 95% CI 1.2 -16), 11.3 (range 6.9-14, 95% CI 8.3-14) and 18 years (range 14-22.1, 95% CI 14-22).

At last visit the mobility of two patients (4%) had improved: one could transfer from bed to wheelchair and one needed one walking stick instead of two.

Progression in timed walks

Comparing baseline with last visit, mean timed walk deteriorated in 29 (81%) by +4.25 sec/10m/year (-0.13 to 24.6, median 1.27) including four patients who became wheelchair bound with median deterioration rate of +17.1 sec/10m/y (+5.9 to +24.6). In seven patients (19%) timed walk improved by -35.5 sec/10m/y (-160 to -2.6, median -7.7) however these patients were followed up for only a median of 0.4 years (0.25-0.92) and the rate of improvement in timed walk has been assumed to continue at the same rate for the whole year and is therefore an overestimate. Timed walks deteriorated even in patients who walked without any need for further aid by a median of + 1.98 sec/10m/year. Four (11%) patients were categorised as long term non-progressors: their median timed walk rate changed by only +0.2 sec/10m/y (-0.13 to + 0.67) without needing any additional aid during a median follow up 4.3 years (2.7-6.8). Two (6%) patients were slow-progressors: they needed one walking stick after a median of 11.5 years (9.7-13.2) disease duration and their median timed walk deteriorated by only +0.3 sec/10m/y (+0.24 to +0.33) during a median follow up of 6.3 years (5.3 -7.3, ). Three (6%) patients progressed rapidly and became wheelchair or bed-bound in less than two years from onset, one of whom died at the age of 40 years. Timed walk, rate of progression and HTLV-1 VL were analysed by age of onset as presented in other publications [START_REF] Matsuzaki | HTLV-I proviral load correlates with progression of motor disability in HAM/TSP: analysis of 239 HAM/TSP patients including 64 patients followed up for 10 years[END_REF][START_REF] Olindo | Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study[END_REF] . Patients with a younger age of onset (≤ 50 years) were more likely to use walking aids (p=0.005) and suffer from pain (p=0.03) at baseline compared to older onset group.

Four patients cited blood transfusion as their only risk for HTLV-1 acquisition of which three patients recalled first symptoms at a young age (≤ 50 y.

Although none of the patients progressed rapidly or died during follow up, two patients needed more aid (a frame and a wheelchair) and the median rate of progression of timed walk was faster in these (+4.9 sec/10m/y [0.5-13.3], 95%CI -9.8 -+22) compared to non-transfused patients (+1.2 sec/10m/y [0.01-6.6], 95% CI +1.1-+3, p 0.02).

Pain

Twenty-seven (63%) patients reported pain at first visit and 23 (53%) at last review (p=0.3). At both time points more patients had permanent compared to intermittent pain (first: 11 [69%] v 5 [31%], last: 13 [81%] v 3 [19%]). Low back pain alone was reported in 14 (52%), low back and leg pain in 7 (26%) and leg pain alone in 5 (19%). At last visit 8 (30%) patients had become pain free but 4 (25%) previously pain free patients reported pain.

The median pain score of the whole group did not differ significantly between first, 6 cm (2-10, 95%CI: 4.9-7.1) and last visit, 5.5 cm (1.5-10, 95%CI: 5.2-7.6, p = 0.2). This however masks the considerable individual changes. In 10 patients the pain score worsened significantly from a median of 2.5 cm (0-8, 95%CI: 0.8-5.2) at first visit to 8 cm (4-10, 95%CI: 5.7-8.8, p=0.05) at last visit.

In 15 patients pain improved significantly between the two time points (first: 7cm [2-10], 95%CI: 5-8; last: 0cm [0-9.5], 95%CI: 0.8-4.4).

Bladder and Bowel function

Although there was no significant difference in the number of patients complaining of bladder problems at the two time points (first: 37/41 [90%] v last 35/41 [85%], p= 0.5), significantly more patients were catheterising at last Twenty-five (63%) were constipated at first and 24 (60%) at last visit. This apparent lack of change masks considerable individual variation. In seven (18%) patients constipation worsened between first and last visit, whilst in ten (25%) it improved of whom seven (18%) became asymptomatic.

Mortality

During follow up five (10.6 %) patients died giving a mortality rate of 2.4/100 py. Three patients were male and the median age at time of death was 57 years (36-78). Four deaths were directly associated with HTLV-1 infection: one patient developed adult T-cell leukaemia/lymphoma, one pneumonia with respiratory failure and two had severe HAM with disseminated inflammation.

Cause of death of one patient was unknown. Death occurred at a median of 9.7 years from onset (2.42-20.3) and 4.4 years of follow up (1.34-10.7) (Figure 1).

HTLV-1 viral load

The HTLV-1 viral load (VL) of the cohort remained essentially unchanged over time (first: median 14 [0.002-140], 95% CI: 13-28 v last: median 13 [0.01-70], 95%CI: 13.3-24, p= 0.6, Figure 2). The median VL of the asymptomatic patient who developed HAM was high at baseline (9.8 [1.6-22.5] copies/ 100 PBMCs) and remained unchanged over time.

HTLV-1 VL was neither associated with a change in aid usage (p=0.8) nor with pain at baseline (p= 0.7). Timed walk deterioration rate was not significantly associated with HTLV-1 VL at baseline (p=0.2). However median HTLV-1 VL were higher in patients who were younger at onset and whose need for aid and timed walk increased over time (≤ 50y:11.2 [0.002-70], 95% CI 5.7 -38; > 50y: 1.7 [1.2-2.4], 95% 0.8-2.7, p= 0.09).

Prediction of deterioration of gait

In a logistic regression analysis investigating the association of an increase in AID usage with the in the methods section mentioned variables identified the rate of progression of timed walk/year (p= 0.05, 95%CI 1-1.3) as the only significant parameter which predicted 69% of progression in aid correctly. A relationship between the rate of timed walk change/ year and the in the methods section listed baseline measurements could not be established in a univariate general linear model.

Discussion

On the basis of ethnicity our cohort data should be most comparable with data from the Caribbean and from Brazil [START_REF] Araujo | Progression of neurological disability in HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP)[END_REF][START_REF] Olindo | Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study[END_REF] . Similarities are the female predominance, route of HTLV-1 acquisition, onset before the age of 50, gait impairment as the most common first symptom and slow but continuous progression of disability as well as a high but stable HTLV-1 VL over time.

On average patients are diagnosed earlier after the onset of HAM in the UK (mean 3.8, median 2 years) than in Martinique (mean 5.3, median 3 years). This might be due to patients' ability and/or choice to access healthcare earlier. In the UK patients could walk unaided for longer (10 v 6 y) and needed a wheelchair later (18 v 21y) than patients in Martinique. The difference in the time to first use of a walking aid could be due to an earlier diagnosis of HAM and/or more intense physiotherapy and symptomatic treatment of pain and spasticity in the UK.

Patients who were younger at onset had a higher baseline HTLV-1 VL and progressed more rapidly as assessed by use of walking aids and timed walk.

In addition the few patients whose risk for acquiring HTLV-1 infection was blood transfusion were also more likely to progress in their need for aid. The rate of deterioration of timed walk seemed to be weakly associated with higher HTLV-1 viral load at first visit irrespective of an increase of aid usage in our cohort. These associations might be more significant in a larger cohort. Timed walk rate is most meaningful for those patients who are not using any aid and are followed up for more than one year. We describe for the first time the expected rate of deterioration in walking speed of 2 sec/10m/y in patients with HAM who do not require any change in walking aid. Thus according to current disability scales only 54% of our initially ambulant patients would have had a documented deterioration whereas using timed walk a further 20% of patients were seen to deteriorate during follow up. Our data, demonstrating improvement in timed walk in patients who have only been attending the clinic for between 3 and 12 months, whilst suggesting that symptomatic management and physical therapy can have a significant impact on mobility in the short-term, should also caution that this may mask continuing progression of the underlying pathology. For the first time we are describing patients with HAM whose rate of timed walk changed only ≤ 1 sec/10m/y from baseline during a follow up time of ≥ 2 years as non-progressors if they did not need any walking aid and as slow-progressors if they needed only one additional aid. These definitions will help to compare HAM subgroups with those who progress continuously or rapidly. Furthermore we have seen that the rate of deterioration in timed walk in patients who subsequently became wheelchair dependent was much faster, suggesting that timed walks identify those patients most at need of therapeutic intervention.

HTLV-1 infection was associated with a 1.3 fold increased risk of death from all causes excluding ATLL in Japan [START_REF] Arisawa | Human T-lymphotropic virus type-I infection, survival and cancer risk in southwestern Japan: a prospective cohort study[END_REF] . The relative mortality rate was 1.7 for HTLV-1 infected compared to uninfected subjects in Guinea -Bissau and was mortality associated with higher HTLV-1 viral loads but neither the cause of death nor the prevalence of ATLL are given [START_REF] Holmgren | Mortality associated with HIV-1, HIV-2, and HTLV-I single and dual infections in a middle-aged and older population in Guinea-Bissau[END_REF] . 25% of 123 patients with HAM from Martinique died within 20 years of disease onset [START_REF] Olindo | Natural history of human T-lymphotropic virus 1-associated myelopathy: a 14-year follow-up study[END_REF] . A report from the UK's Health Protection Agency documented a higher mortality rate associated with HTLV-1 infection in the UK in patients of Afro-Caribbean ethnicity and in those living far from centres looking after HTLV-1 positive patients [START_REF] Tsui | Mortality among individuals less than 60 years diagnosed with HTLV-I in England and Wales[END_REF] . In our population 10.6% of the patients with HAM died within a mean of 9.7 years from the onset of HAM. The mortality rate in our cohort was 2.4/100 py follow up compared to an age-adjusted mortality rate of 1/100 py in general UK population. Therefore a higher rate of all cause non-neoplastic mortality is associated with HAM in the UK. Deaths in our cohort were more common in younger, more disabled patients and appeared to be more directly related to HTLV-1 infection, whereas in Martinique deaths were mostly commonly due to complications of debilitating neurological disease.

We also present prospectively collected longitudinal data on HTLV-1 VL of patients with HAM. Neither the mean nor the median HTLV-1 viral load changed significantly over time and more importantly the patient who developed HAM during follow up had a high set point of HTLV-1 VL prior to onset of symptoms which fluctuated only insignificantly over time. However we do not have enough data to prove that a significantly higher VL always precedes the development of HAM although this is commonly assumed.

This study has the many limitations of a cohort study of a rare disease: small numbers, variable follow up in some cases < 1 year, no comparator arm and not controlled for treatment. The underlying deterioration of HAM resulting in a steady deterioration may obscure fluctuating improvements in patients followed up for longer as only the final outcome is documented. Therefore a potential transient improvement or stalling of the disease process might have been missed. However, careful description of a cohort essentially managed with only symptomatic therapies provides a rate of change in timed walk against which novel interventions can be judged. In conclusion, a 10m timed walk, which is simple and accessible, provides a rapid and valuable additional clinical measure in patients with HAM, demonstrating the continuous progressive nature of this condition and a tool to identify patients who might most benefit from more targeted management Funding: None.

Competing interests: None.

  parametric tests (Mann-Whitney Test and Wilcoxon Signed Ranks Test) for continuous variables and chi-square (Pearson Chi-Square Test/ Fisher's Exact test) for categorical variables. The categorical variables were gender, ethnicity, perceived risk factor for HTLV-1 infection, first recalled symptom, use of walking aids, localisation of pain, bladder and bowel function and death. The continuous variables were age at onset, age at diagnosis of HTLV-1 infection or of HAM, duration of disease and follow up, timed walk, pain score and HTLV-1 viral load. Kaplan Mayer survival analysis was used for survival data. For the prediction of AID change a logistic regression model was applied, using the following explanatory variables: age of onset, risk factors for HTLV-1 acquisition, HTLV-1 VL, rate of change timed walk, timed walk, absence/presence of pain and pain score at first visit. For the prediction of the deterioration of timed walk an univariate general linear regression model was used, analysing the effects of the following covariates: age of onset, HTLV-1 VL, timed walk and pain score at first visit and fixed factors: gender, ethnicity, risk factor for HTLV-1 infection and absence/presence of pain. Forward and backward Wald was used for the best-fit model. Cox regression was used to create a predictive model for time-to-event data.

20 (

 20 49%) compared to first visit 11 (27%) p=0.04. Most patients suffered from bladder hyperactivity (32 [86%]) and urinary retention was observed in five [14%]. Obstructive nephropathy was present at baseline in one patient and developed during follow up in a second.

Figure 1 :

 1 Figure 1: Kaplan Maier survival analysis of all patients from onset of disease to last follow up or death. Censored = patient reaching their last follow up.

Figure 2 :

 2 Figure 2: Mean HTLV-1 viral load (log copies/ 100 PBMCs) of all patients by year of follow up. SD= standard deviation, PBMCs= peripheral blood mononuclear cells

Table 1 :

 1 Demographics, follow up and treatment of 48 patients with HAM.

	Gender