Toumi et al. (2013) observed a positive associationof PF in Tunisia with the T;A-C-A combination forrs2243250 (of IL4), andrs4787948–rs3024622–rs3024530 (of IL4R),raising the hypothesis that genetic variation of IL-4 and IL-4Rα interact andplay a central role in the regulation of pathogenic IgG4 antibody production orthe clinical course of the disease. In contrast, polymorphisms of theIL13 gene and IL13RA2 (that encodes oneIL-13 receptor chain; located in Xq24) were not associated with the disease(Toumi et al.,2013). Here, IL4 is linked to pemphigus foliaceus.