Since the occurrence of cholangitis was completely abrogated only in p40−/− mice but not in Th17-deficient mice (p19−/−, IL-17A−/− and IL-22−/−) and Th1-deficient p35−/− mice, we next attempted to determine the role of IFN-γ in the induction of cholangitis. This evidence concerns the gene IL23A and cholangitis.