IL5 and immunoglobulin G4-related sclerosing disease: From the view of the cytokine profile of IgG4-RD includes Th2 cytokines (IL-4, IL-5, and IL-13) and regulatory cytokines (IL-10 and tumor growth actor [TGF]-β), the Th2 immune response play a key role in the pathophysiology of type1 AIP including IgG4-RD [76–79].