Serum levels of soluble PD1 in pemphigus vulgaris: A useful marker for disease severity.

Abstract

Pemphigus vulgaris (PV) is a life-threatening autoimmune blistering disease targeting the skin and mucous membranes. Programmed cell death protein 1 (PD1) is an immune checkpoint which binds to two ligands, PDL1 and PDL2 resulting in negative regulation of antigen receptor signaling, thus, play a critical role in the immune regulation of autoimmune diseases. In this work we aimed to assess serum levels of soluble PD1 (sPD1) in patients with active PV and in patients in remission in an attempt to evaluate its effect on disease severity. In this case-control study, 60 pemphigus vulgaris patients (30 clinically active and 30 in a clinical remission) and 30 age matched healthy control subjects were included. Severity of PV was assessed using pemphigus disease area index (PDAI) score. Serum levels of sPD1 were measured by ELISA for both patients and healthy control. Serum levels of sPD1 were significantly lower in PV patients than in controls (P<.001) and significantly lower in patients with active disease than in those in remission (P<.001). Serum sPD1 correlated negatively with the severity of the disease (P<.001, r=-0.4). A defect in PD1 pathway is suggested in PV patients, and this defect plays a substantial role in determining the severity of the disease. Thus, sPD1 could be considered a useful marker for disease severity and targeting PD1 pathway could be a potential aim for future therapies of PV.