IL31 and psoriasis: While the IL-23/T-helper (Th)17 inflammatory pathway, which involves tumor necrosis factor (TNF)-alpha, IL-23, and IL-17, is critically involved in psoriasis pathogenesis (35, 36), the Th-2 pathway, primarily involving IL-4, IL-5, IL-6, IL-10, IL-8, IL-18, and IL-31, has been identified as the essential driver of BP antibody production (37–40).