There might be a role for CD200 in the pathogenesis of autoimmune and inflammatory skin disorders

BACKGROUND Soluble 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. MATERIAL/METHODS Our 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. RESULTS The serum sCD200 level was observed to be statistically significantly higher in patients with psoriasis vulgaris (96.7±15.8) compared to patients with pemphigus vulgaris (76.2±14.6), (p<0.001) and healthy controls (26.8±7.0) (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). CONCLUSIONS sCD200 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.