Ulcerative colitis associated with IgG4 cholangitis: Similar features in two HLA identical siblings

IgG4-associated cholangitis (IAC) can mimic primary sclerosing cholangitis although, in contrast to the latter, it is highly responsive to steroid therapy. IAC is known to be associated with autoimmune pancreatitis and has also been shown to be part of a more complex autoimmune IgG4 syndrome. However, an association with inflammatory bowel disease (IBD), a condition in which its identification may have therapeutic and prognostic importance, has not yet been described.We report the cases of two HLA identical siblings both DRB *1501 positive exhibiting features of IAC together with ulcerative colitis. Subsequent high resolution HLA typing performed by sequence-based-typing showed similar alleles in both siblings: A *0301 A *3201 B *07 (0702/62) B *1401 C *0702 C *0802 DRB1 *1501. There is indirect evidence that this hitherto undescribed association, likely to be strongly linked to a genetic background, might account for a proportion of the cases of cholangitis associated with IBD.Appropriate investigation for IBD-associated cholangitis is mandatory to identify IAC, the recognition of which has particular therapeutic and prognostic implications.