IL4 and acquired polycythemia vera: Objective: The purpose of this study was to assess the serum levels of cytokines produced by the Th1 (IFN‐γ, IL-12), Th2 (IL‐4), Th17 (IL-6, IL‐17A, IL‐23), and Treg (IL‐10 and TGF-β) pathways in individuals with active pemphigus vulgaris (PV) and to determine whether these levels were correlated with the severity of the disease condition.