the consequence of this interaction is to dampen the inflammatory response , with ligation of cd200r a therapeutic target in collagen - induced arthritis . .   showed that circulating t(fh ) cells from patients with rheumatoid arthritis show significantly increased expression of cd200 , with highest levels seen in seropositive patients and patients treated with anti - tnf agents . in autoimmunity , the cd200-cd200r signaling rosenblum et al .   reported that the expression of cd200 in follicular epithelium attenuates inflammatory reactions and may play a role in maintaining immune tolerance to hair follicle - associated autoantigens . .   showed that monoclonal antibody - mediated cd200 receptor signaling suppresses macrophage activation and tissue damage in experimental autoimmune uveoretinitis . our research group recently showed the presence of soluble cd200 in serum and blister fluid in a patient with bullous pemphigoid and demonstrated the impact of anti - ige therapy on those levels . as the second findings about cd200 in immunologic response in skin , we found that soluble cd200 ( scd200 ) levels were higher in blister fluid than serum in patients with toxic epidermal necrolysis . we therefore planned this study to evaluate the soluble serum cd200 levels in patients with autoimmune and inflammatory skin disorders and to compare it with that of healthy controls . we also analyzed the association between the serum soluble cd200 levels and the clinical severity of the disease in these patients . , there were 30 consecutive patients with psoriasis vulgaris , 15 with pemphigus vulgaris , and 25 healthy controls . before the initiation of any treatment , diagnosis of pemphigus vulgaris was confirmed by histology , direct immunofluorescence , and detection of circulating anti - desmoglein 1 and anti - desmoglein 3 autoantibodies by elisa . pemphigus patients were also assessed for clinical severity score according to the pemphigus disease area index ( pdai ) . healthy volunteers had no history of allergy / atopy , family atopy , or cardiac , liver , renal , or pulmonary diseases . the study was approved by the local ethics committee , and written informed consent was obtained from all patients and healthy volunteers . circulating anti - desmoglein 1 and anti - desmoglein 3 autoantibody levels were measured using desmoglein 1 and desmoglein 3 microplate elisa kits ( euroimmun , germany ) . concentrations of scd200 in the serum samples were quantified using an elisa kit ( sino biological inc . , blood samples for scd200 measurement were always taken in the morning between 8 and 10 am . statistical analyses were performed using spss software ( version 18.0 ; spss , chicago , il , usa ) . comparison of parameters groups was performed using the t test , the chi squared test , and anova . , there were 30 consecutive patients with psoriasis vulgaris , 15 with pemphigus vulgaris , and 25 healthy controls . before the initiation of any treatment , diagnosis of pemphigus vulgaris was confirmed by histology , direct immunofluorescence , and detection of circulating anti - desmoglein 1 and anti - desmoglein 3 autoantibodies by elisa . pemphigus patients were also assessed for clinical severity score according to the pemphigus disease area index ( pdai ) . healthy volunteers had no history of allergy / atopy , family atopy , or cardiac , liver , renal , or pulmonary diseases . the study was approved by the local ethics committee , and written informed consent was obtained from all patients and healthy volunteers . circulating anti - desmoglein 1 and anti - desmoglein 3 autoantibody levels were measured using desmoglein 1 and desmoglein 3 microplate elisa kits ( euroimmun , germany ) . concentrations of scd200 in the serum samples were quantified using an elisa kit ( sino biological inc . , blood samples for scd200 measurement were always taken in the morning between 8 and 10 am . statistical analyses were performed using spss software ( version 18.0 ; spss , chicago , il , usa ) . comparison of parameters groups was performed using the t test , the chi squared test , and anova . the serum soluble cd200 level was observed to be statistically significantly higher in patients with psoriasis vulgaris ( 96.715.8 ) compared with that in patients with pemphigus vulgaris ( 76.214.6 ) ( p<0.001 ) and healthy controls ( 26.87.0 ) ( p<0.001 ) . main demographic , clinical , and diagnostic characteristics , and cd200 levels in the study population are presented in table 1 . there was a statistically significant correlation between serum soluble cd200 levels and clinical severity scores for pemphigus vulgaris ( r=0.987 , p=0.001 for pdai ) . there was no statistically significant correlation between serum soluble cd200 levels and clinical severity scores for psoriasis vulgaris ( r=0.154 , p=0.407 for pasi ) . the serum soluble cd200 level was observed to be statistically significantly higher in patients with psoriasis vulgaris ( 96.715.8 ) compared with that in patients with pemphigus vulgaris ( 76.214.6 ) ( p<0.001 ) and healthy controls ( 26.87.0 ) ( p<0.001 ) . main demographic , clinical , and diagnostic characteristics , and cd200 levels in the study population are presented in table 1 . there was a statistically significant correlation between serum soluble cd200 levels and clinical severity scores for pemphigus vulgaris ( r=0.987 , p=0.001 for pdai ) . there was no statistically significant correlation between serum soluble cd200 levels and clinical severity scores for psoriasis vulgaris ( r=0.154 , p=0.407 for pasi ) . cd200 is a novel immuno - effective molecule , both cell membrane - bound and also existing in a soluble form in serum ( scd200 ) , which acts to regulate inflammatory and acquired immune responses through interaction with cell - bound ligands , cd200r . we investigated soluble cd200 , which can also be linked to apoptosis and is an immuno - effective ligand . in a murine model of passive cutaneous anaphylaxis , cross - linking of cd200r1 in vivo produced profound suppression , greater than that seen following in vitro cd200r1 activation , which it was felt might reflect higher constitutive expression of cd200r1 on mast cells in vivo compared with cells maintained in culture , and/or the existence of other cell - cell interactions in vivo , which could lower the threshold for cd200r1-mediated suppression . regardless , these data were taken to imply a potential clinical utility for cd200-cd200r1 in regulation of allergic inflammatory disease . this skin condition is histologically characterized by abnormal proliferation of keratinocytes and infiltration of immune cells , predominantly t cells and dendritic cells in psoriatic lesions . the majority of inflammatory cells and cytokines remain in the tissue , and a relatively small proportion can be measured in the peripheral blood , including interleukins , which have shown to be elevated in patients with cardiovascular disease , metabolic syndrome , and diabetes . pemphigus vulgaris is widely believed to result from the deleterious action of autoantibodies directed against desmoglein 1 and desmoglein 3 , resulting in loss of cell  cell adhesion within the epidermis and increased cell apoptosis . the discovery of new immunological factors and a better understanding of these disorders could help to develop new biomarkers and biological drugs against specific immunological elements that cause psoriasis and pemphigus . in our study , there was a power correlation between cd200 levels and clinical severity , suggesting that cd200 could be of potential importance as a biomarker of autoimmune and inflammatory skin disorders . showed that targeted therapy is feasible and may be useful for hyperproliferative and inflammatory skin diseases . they chose trail as a biological model because it inhibits activated lymphocytes and causes apoptosis of hyperproliferative keratinocytes , which are features of various skin diseases . our study showed that cd200 could play a role in maintaining pro - inflammatory reactions or immune tolerance in autoimmune and inflammatory skin disorders . taken together , the findings of our study and previous investigations suggest the therapeutic potential of cd200 targeting agents in the treatment of skin disorders such as psoriasis , pemphigus , and bullous pemphigoid . in our previous study , we reported the case of a man with pruritic bullous pemphigoid and very high levels of total ige ( 5000 ku / l ) who was refractory to the aggressive immunosuppressive regimens ( systemic steroids , daily cyclophosphamide ) for bp but who responded rapidly to systemic anti - ige ( omalizumab ) . the circulating level of scd200 was 48.45 pg / ml in serum and 243 pg / ml in blister fluid . scd200 levels were higher in blister fluid than in serum . during the second month of follow - up after the second round of omalizumab ( 300 mg ) , the frequency of exacerbations decreased . reduction in serum levels cd200 with anti - ige treatment suggests that cd200 could be pro - inflammatory . in the current study high levels of serum soluble cd200 affect cd200r and try to protect tissue damage during autoimmune responses . in fact , the significantly higher values in psoriasis vulgaris than in pemphigus vulgaris patients and healthy controls could also support the pro - inflammatory effect . in this preliminary study we showed that cd200 might play a role in immune response in the pathogenesis of psoriasis vulgaris and pemphigus vulgaris . cd200 might useful as a biomarker and therapeutic agent in inflammatory response in autoimmune and inflammatory skin disorders . in addition , the study design does not allow establishment of a causal or temporal relationship between high cd200 levels and inflammatory skin disorders .
backgroundsoluble cd200 ( scd200 ) is a novel immuno - effective molecule , which acts to regulate inflammatory and acquired immune responses . 
 recently , our study group showed that scd200 was present in serum and blister fluid in a patient with bullous pemphigoid and a patient with toxic epidermal necrolysis . 
 we therefore planned this study to evaluate the scd200 levels of autoimmune and inflammatory skin disorder patients and to compare them with that of healthy controls.maleral/methodsour study included 30 consecutive patients with psoriasis vulgaris , 15 with pemphigus vulgaris , and 15 healthy controls . 
 clinical examination and laboratory tests were performed on the same day . 
 psoriasis patients were also assessed with the psoriasis area and severity index ( pasi ) and pemphigus patients were assessed using the pemphigus disease area index ( pdai ) . 
 levels of scd200 in the serum samples were quantified using elisa kits.resultsthe serum scd200 level was observed to be statistically significantly higher in patients with psoriasis vulgaris ( 96.715.8 ) compared to patients with pemphigus vulgaris ( 76.214.6 ) , ( p<0.001 ) and healthy controls ( 26.87.0 ) ( p<0.001 ) . 
 the serum scd200 levels were observed to be statistically significantly higher in patients with pemphigus vulgaris compared with that in healthy controls ( p<0.001 ) . 
 in addition , there was a statistically significant correlation between serum scd200 levels and pdai ( r=0.987 , p=0.001 ) . 
 nevertheless , there was no statistically significant correlation between serum scd200 levels and pasi ( r=0.154 , p=0.407).conclusionsscd200 might play a role in immune response in the pathogenesis of autoimmune and inflammatory skin disorders . 
 however , it remains to be fully elucidated how scd200 can orchestrate inflammatory response in psoriasis and pemphigus .