Expression of soluble and membrane-bound programmed death protein 1 in psoriasis vulgaris patients: a case-controlled study

Background and aim programmed cell death-1 (pd1) is an immunoreceptor that negatively regulates antigen receptor signaling and plays a critical role in the immunoregulation of autoimmune diseases. objective the objective of this study was to assess both soluble programmed cell death-1 (spd1) and membrane-bound pd1 levels in psoriatic patients, and to correlate them with disease severity. patients and methods twenty-one psoriatic patients and 20 age-matched and sex-matched controls were included. full clinical examination was done and tissue and blood levels of pd1 were measured by enzyme-linked immunosorbent assay. results levels of spd1 were significantly lower in patients than in controls (p<0.001). regarding the level of tissue pd1, it was lower in psoriatic skin biopsies (0.32 ± 0.22) than in controls (0.54 ± 0.08); however, this difference was not statistically significant (p =0.89). a statistically significant positive correlation was found between tissue and spd1 levels (p= 0.02, r=0.5), and a significant negative correlation with the extent of the disease (p =0.024, r= −0.5). conclusion psoriatic patients have significantly lower spd1 level. pd1 might play an important role in the pathogenesis of psoriasis vulgaris.