it was found that the frequency of plasmacytoid dcs ( pdcs ) is markedly increased in ssc patients . this is illustrated in fig1 . in particular , the frequency of pdcs was increased in patients with the diffuse cutaneous subtype of ssc . the frequency of pdcs was highest in patients suffering from early diffuse ssc . the number of pdcs in individual ssc patients , as compared to normal healthy controls , is shown in fig2 . it was also found that plasma from ssc patients contains high levels of cxcl4 . cxcl4 is a chemokine described to bind to cxcr3 , more specifically , the splice variant cxc3 b , which is in contrast to cxlc9 , cxcl10 and cxcl11 that bind to cxcr3 a ( lasagni et al ., j . experimental medicine 2003 ). cxcl4 is known to induce apoptosis in endothelial cells leading to endothelial cell death . in addition , cxcl4 is known to have potent anti - angiogenic properties and known to induce fibroblast activation via activation of monocyte - derived dendritic cells . cxcl4 was measured in a standard elisa assay and the results are illustrated in fig3 , panel a . it is shown that cxcl4 was overproduced by pdcs of ssc patients since elevated levels of cxcl4 could also be detected in the supernatant of pdcs isolated from early diffuse ssc patients . this is illustrated in fig3 , panel b . it was noted that the production of cxcl4 in pdc supernatant closely mirrored the frequency of pdcs in plasma . since cxcl4 was originally identified as a sole platelet activation marker , the possibility was excluded that platelets contaminated the pdcs supernatants by measuring the β - tg content , which was negligible . hence , it was concluded that cxcl4 is over - produced by pdcs in patients with ssc . this was confirmed in a whole proteome analysis using seldi - tof . analysis of pdc revealed that ssc pdcs were solely committed to produce a few proteins that could be identified as cxcl4 or cxcl4 - precursor molecules . it was also shown that cxcl4 plays a role in fibroblast activation in ssc patients . to that end , the expression of known fibroblast activation markers tgfβr , comp and αsma in healthy fibroblasts co - incubated with ssc plasma was measured . it was found that ssc plasma induced the expression of these markers for fibroblast activation significantly and in a dose - dependent manner ( fig4 ). in addition , the plasma from healthy donors had no effect and the effect of ssc plasma was abrogated using heparinase , a natural antagonist of cxcl4 . it was concluded that an elevated level of pdcs in ssc patients contributes to the fibrotic process . cxcl4 on its own was found to be unable to stimulate pdcs to produce pro - inflammatory molecules ; neither pdcs from normal individuals nor pdcs from ssc patients produced pro - inflammatory molecules . only in the presence of cxcl12 - specific stimulation of pdcs derived from ssc patients could be observed . this is illustrated in fig6 . therein , the production of pro - inflammatory molecules was measured in the presence of pdcs from healthy individuals as compared to pdcs isolated from ssc patients . pdcs from healthy controls were incubated with plasma from ssc patients and healthy controls , after which the production of pro - inflammatory molecules was measured . the addition of plasma from ssc patients and healthy controls had no effect . pdcs from healthy individuals were incubated , as well as from ssc patients with ssc plasma and healthy control plasma , with and without the presence of cxcl12 . it was found that only the combination of ssc plasma and cxcl12 led to a significantly increased level of il - 6 and il - 12 . to assure that this effect was due to the “ auto - activation ” of pdcs by endogenous cxcl4 , cxcl4 was added to the cultures of pdcs from healthy individuals with healthy control serum and cxcl12 . the addition of cxcl4 to these experiments induced il - 6 and il - 12 secretion to the same levels as the combination of ssc plasma and cxcl12 ( fig5 ). in addition , the addition of heparinase fully abrogated the effect of ssc plasma and cxcl12 on pdcs . without wanting to be bound by theory , it was hypothesized that cxcl12 ( also known as sdf - 1 ) binds to cxcr4 , thereby initiating chemo - attractive properties aimed at the recruitment of pdc toward the site of inflammation . cxcl12 is known to be highly presented in the skin of ssc patients and likely to be produced by local fibroblasts . in support of this hypothesis , it is mentioned that monocyte - derived dcs were found to be insensitive to cxcl4 unless cxcl12 is present . it is currently unknown how cxcl12 sensitizes dcs to the effect of cxcl4 ( cipriani et al ., arthritis rheum . 2006 sep ., 54 ( 9 ): 3022 - 33 ). it is known that pdcs are stimulated mostly via toll - like receptor 9 ( tlr9 ), via which they mainly make type i interferons ( ifns ). as such , pdcs are considered the main producers of this cytokine . challenged by the question “ what induces the increased cxcl4 production by pdcs ,” the role of toll - like receptors ( tlr ) was investigated . these experiments showed that tlr3 -, tlr7 / 8 - and tlr9 - mediated stimulation induced cxcl4 secretion by pdcs . interestingly , dcs from ssc patients were found to produce much more ifns and il6 than those from healthy controls ( fig6 ). a clearly increased secretion of ifnα in lcssc patients , ldssc patients and edssc patients was observed . this shows that the potentiated tlr response by pdcs is caused by a cxcl4 - dependent tlr augmentation . in support of this , neutralization of cxcl4 led to a full abrogation of this tlr augmentation , showing that cxl4 underlies this phenomenon ( fig7 ). to further substantiate these findings , pdcs from healthy controls were incubated with cxcl12 , cxcl4 or its combination dose dependently . these experiments demonstrated that cxcl4 in combination with cxcl12 led to an augmentation of the tlr response . in conclusion , these observations show that cxcl4 ( in conjunction with cxcl12 ) plays a central role in the pathogenesis of ssc . the mechanism for that is auto - activation of pdcs resulting in a potentiated tlr response and further cxcl4 production . patients with ssc may , therefore , benefit from methods that remove cxcl4 and / or pdcs , for instance , from the blood circulation . that may be accomplished in a number of ways , which are known in the art per se . patients with scleroderma may benefit from a treatment wherein the effects of the cxcl4 produced in excess are neutralized or counteracted , for instance , by removing cxcl4 from circulation . in the alternative , cxcl4 may be prevented from binding to its receptor . the disclosure , therefore , relates to a compound capable of binding to cxcl4 for use in the treatment or prevention of fibrosis in patients with scleroderma . compounds capable of binding to cxcl4 may be compounds capable of binding to cxcl4 under physiological conditions . compounds capable of binding to cxcl4 per se are known in the art . for instance , fragments of the receptor or fragments of cxcl4 will be suitable compounds . in a preferred embodiment , specific antibodies may be employed in order to remove cxcl4 , for instance , from the circulation . this may be accomplished by plasmapheresis . antibodies against cxcl4 are available in the art . they have been described , for instance , in vandercapellen et al ., j . leukocyte biol . 82 , 1519 ( 2007 ), and are commercially available from r & amp ; d systems , 614 mckinley place ne , minneapolis minn . 55413 . given the teachings of this disclosure , it will be within the routine skills of a person skilled in the art to design and develop materials and methods for removing or counteracting the effects of cxcl4 and / or dcs such that patients with ssc may benefit from these materials and methods . for that purpose , cxcl4 antagonists may be advantageously employed . antagonists for cxcl4 are known to the skilled person . as an example , heparinase is disclosed and exemplified herein . in another embodiment , the disclosure also relates to a compound capable of interfering with the in vivo production of cxcl4 for treatment or prevention of fibrosis in patients with scleroderma . compounds capable of interfering with the in vivo production of cxcl4 per se are known in the art . the disclosure , therefore , also relates to a method for treatment or prevention of fibrosis in patients with scleroderma by interfering with the in vivo production of cxcl4 . such methods may encompass interference at the level of transcription or translation of cxcl4 . such methods are known in the art and may now advantageously be used in the treatment of scleroderma . a reduction in the level of cxcl4 in a patient &# 39 ; s body may be accomplished by a therapy in vivo . alternatively , patients with ssc may also benefit from in vitro methods that reduce the level of cxcl4 in blood . such may be done directly by applying a compound capable of binding to cxcl4 and contacting that compound with blood obtained from a patient with ssc . it may also be accomplished by reducing the number of dc that produce the cxcl4 in patients with scleroderma . this may also be accomplished in an in vitro method wherein the previously isolated blood or plasma from a patient with scleroderma is contacted with a compound or device capable of reducing or depleting the number of pdcs in solution . the disclosure , therefore , also relates to an in vitro method for reducing the level of cxcl4 and / or the number of pdcs in blood obtained from a patient with scleroderma . in more detail , the disclosure relates to an in vitro method for reducing the level of cxcl4 and / or the number of pdcs in a sample obtained from a patient with scleroderma , comprising the steps of : a . providing the sample obtained from a patient with scleroderma b . contacting the sample with a compound capable of binding to cxcl 4 c . allowing the compound to bind to cxcl4 in order to form a complex d . removing the complex from the sample , thereby reducing the level of cxcl4 and / or the number of pdcs . devices capable of reducing the level of cxcl4 and / or pdcs in blood are known in the art . preferably , cxcl4 and / or pdcs are removed from circulation , for instance , using a commercially available technique provided by miltenyi ( jongbloed et al ., arthritis res . ther . 2006 , 8 ( 1 ): r15 ). miltenyi produces and markets such a device that may be advantageously used in the new treatment according to the disclosure . hence , the disclosure relates to a device capable of reducing the level of cxcl4 and / or pdcs in blood for the treatment or prevention of fibrosis in patients with scleroderma . alternatively , a method according to the disclosure may also comprise a step wherein the binding of cxcl4 to its receptor is blocked or otherwise prevented or down - regulated or decreased . the disclosure , therefore , also provides a method for treatment or prevention of fibrosis in patients with scleroderma by interfering with the binding of cxcl4 to its receptor . pbmcs were isolated from heparinized venous blood ( 100 ml ) by using density - gradient centrifugation over ficoll - paque ® ( amersham bioscience ). next , plasmacytoid dcs ( pdcs ) were isolated using the bdca4 magnetic isolation kit from miltenyi biotec according to the manufacturer &# 39 ; s protocol . all procedures were carried out on ice and after the isolation of pdcs , these cells were counted using counterchambers and directly transferred to rpmi medium without any additions in a concentration of 1 million cells / ml . after pelleting , the supernatant was collected and stored at − 80 ° c . until further analysis . the cells were then resuspended in rpmi supplemented with 2 nm l - glutamine , 100 u / μl / ml penicillin / streptomycin ( life technologies ), and 10 % fcs ( biowhittaker ), after which cells were brought into culture for further analysis . directly after isolation , a part of the bdca4 + cells were resuspended in facs buffer and were analyzed for the expression of bdca1 , bdca2 , bdca3 , cd80 , cd86 , mhc and fcγrs applying standard flow cytometry protocols . during the first experiments , the pdcs diamond kit from miltenyi biotec was exploited to replicate the data having so - called “ untouched pdcs .” in all experiments , direct dc enumeration was performed using the dc enumeration kit from miltenyi biotec according to the manufacturer &# 39 ; s protocol . supernatant from unstimulated pdcs was stored after 1 and 24 hours of culture . in addition , pdcs were stimulated with ligands specific for toll - like receptor 2 ( tlr2 , pam3cys ), tlr3 ( poly - ic ), tlr4 ( lps ), tlr7 / tlr8 ( r848 ) and tlr9 ( cpg ) for 24 hours , after which , supernatant was collected . in all these supernatants , the levels of multiple inflammatory mediators ( il - 8 , tnf , ifnγ , ifnα , mcp - 1 , mip1β , il - 6 , il - 1β , il - 12 . il - 23 , il - 17f , il - 17a ) were measured using luminex technology as previously described ( roelofs et al ., arthritis rheum . 2005 aug ., 52 ( 8 ): 2313 - 22 ; roelofs et al ., ann . rheum . dis . 2009 sep ., 68 ( 9 ): 1486 - 93 , epub 2008 sep . 2 ; wenink et al ., j . immunol , 2009 oct . 1 , 183 ( 7 ): 4509 - 20 , epub 2009 sep . 4 ). to study the full proteome in pdcs , the 1 - hour spontaneous supernatants were used for analysis in the seldi - tof . exploiting this technique , 40 supernatants were tested originating from healthy controls ( n = 10 ) and ssc patients having limited cutaneous ( n = 10 ), late diffuse ( n = 10 ) and early diffuse ( n = 10 ) disease as previously described ( radstake et al ., plos one 2009 ). the expression of cxcl4 and β - tg was measured by commercially available elisas used following the manufacturer &# 39 ; s protocols . example 3 : stimulation of plasmacytoid dcs and investigating the self - perpetuating loop since the literature suggests an important role for cxcl12 in the cxcl4 - mediated activation of pdcs , the potential role of this loop in ssc was investigated ( van der vliet et al ., j . experimental medicine 2003 sep . 1 , 198 ( 5 ): 823 - 3 ). to this aim , pdcs from healthy controls and ssc patients were first co - cultured with combinations of cxcl4 and / or cxcl12 . during these experiments , pdcs were cultured with rpmi only , rpmi / cxcl12 , rpmi / cxcl12 / cxcl4 and rpmi / cxcl12 / heparinase . in addition , the effect of cxcl4 on the tlr pathways was investigated by pre - incubation of pdcs with cxcl4 or the combination cxcl4 / cxcl12 , after which , pdcs were consecutively stimulated with tlr ligands . after 24 hours of incubation , the production of ifnα , il - 12 and il - 6 was measured by luminex . skin fibroblasts were isolated from healthy skin biopsies and cultured according to standardized protocol as described previously ( farina , ann . rheum . dis . 2009 mar ., 68 ( 3 ): 435 - 41 ). when confluent , fibroblasts were replated and cultured for an additional 24 hours to allow attachment to the culture plates . subsequently , fibroblasts were incubated with combinations of plasma from healthy controls and ssc patients , plasma and heparinase and cxcl4 / cxc12 . after 48 hours of culture , the expression of comp was measured by real - time pcr as previously described ( farina , ann . rheum . dis . 2009 mar ., 68 ( 3 ): 435 - 41 ).
the disclosure is in the field of molecular immunology , more in particular , in the field of the prevention or treatment of autoimmune diseases , more in particular , systemic sclerosis or scleroderma . the disclosure is based on the observation that ssc patients have an elevated plasma level of cxcl4 . this was found to contribute to the pathogenesis of ssc , in particular , fibrosis . when cxcl4 was neutralized in in vitro experiments , the fibrotic effects could be neutralized . this led us to conclude that ssc may be cured by reducing the plasma level of cxcl4 . the disclosure , therefore , relates to a method for treatment or prevention of fibrosis in patients with scleroderma , wherein the plasma level of cxcl4 is reduced .