Background: CD200 is a novel immunosuppressive molecule, existing both as cell membrane bound and as a soluble form in serum (sCD200), which acts to regulate inflammatory and acquired immune responses. Recently, our study group showed that sCD200 was found in serum and blister fluid in a patient with bullous pemphigoid and that anti-IgE therapy impacted those levels. We therefore planned this study to evaluate the soluble serum CD200 levels of bullous pemphigoid patients and compare it with that of healthy controls. We also analysed the association between the sCD200 levels and the clinical severity of the disease in bullous pemphigoid patients.
Methods: We investigated 5 consecutive patients with bullous pemphigoid, and 15 healthy controls were included in this study. Assessment of clinical examination and measurement of laboratory investigation were performed on the same day. Bullous pemphigoid patients were also assessed for Autoimmune Bullous Skin Disorder Intensity Score (ABSIS). Concentrations of anti-BP180 and soluble CD200 in the serum samples were quantified using ELISA kits.
Results: The serum soluble CD200 level was observed to be statistically significantly higher in patients with BP (77.6 ± 15.7 pg/mL) compared with healthy controls (26.1 ± 6.7 pg/mL), (p < 0.001). Nevertheless, there was no statistically significant correlation between serum soluble CD200 levels and clinical severity scores and Anti-BP180 values (p = 0.402, p = 0.395, respectively). However, there was a statistically significant correlation between ABSIS and Anti-BP180 levels in patients with BP (p = 0.036).
Conclusions: CD200 might play a role in the immune response in the pathogenesis of bullous pemphigoid. However, we do not know the exact mechanism of CD200 in the disease initiation and/or progression.