Decreased Serum Levels of Interleukin-4 and Interleukin-21 in New Pemphigus Vulgaris Patients, but Not Chronic Patients With Inactive Disease Compared to Healthy Controls

Background: Pemphigus is a rare group of autoimmune blistering diseases with unknown etiology and unclear pathogenesis. Pemphigus vulgaris (PV) is the most common subtype, and is characterized by ulcerations or flaccid blisters on mucous membranes and on the skin. It is accepted that cytokines have a critical role in the pathogenesis of PV, while their exact roles remain to be elucidated. Objectives: This study assessed serum levels of interleukin (IL)-4 and IL-21 in different phases of the disease in comparison with healthy controls. Methods: In a case-control cohort design, serum levels of IL-4 and IL-21 were determined by ELISA in three groups: patients with newly diagnosed PV, patients with chronic, inactive PV (PV in remission), and healthy controls. Results: The study included 88 individuals (58 women and 30 men), including 26 with newly diagnosed PV, 33 with PV in remission, and 29 healthy controls. A significant difference was found among the groups for IL-21 (P = .044), but not for IL-4 (P = .374). Serum levels of IL-4 and IL-21 in newly diagnosed patients were significantly lower than in healthy controls (P = .005 for both), but these cytokine levels in patients with PV in remission were not different from those of controls (P = .343 and P = .221, respectively). Also, no differences in cytokine levels were detected between the newly diagnosed patients and patients with PV in remission. Regardless of disease phase, we detected significantly lower levels of IL-21 in patients than controls (P = .027), but no differences for IL-4 (P = .374). Conclusions: IL-4 and IL-21 are involved in PV pathogenesis and disease severity. More studies are required to clarify the role of IL-4 and IL-21 in immunopathogenesis and immune response during PV.