ORiginal Article

associated with autoimmune pancreatitis (AIP). Infiltration of immunoglobulin G4 (IgG4)-positive plasma cells is some-times detected in the colonic mucosa of AIP or UC patients. This study aimed to clarify the relation between UC and IgG4. Methods: Associations with UC were reviewed in 85 AIP pa-tients. IgG4 immunostaining was performed on biopsy speci-mens from the colonic mucosa of 14 AIP and 32 UC patients. Results: UC was confirmed in two cases (type 1 AIP, n=1; suspected type 2 AIP, n=1). Abundant infiltration of IgG4-positive plasma cells in the colonic mucosa was detected in the case of suspected type 2 AIP with UC and two cases of type 1 AIP without colitis. Abundant infiltration of IgG4-posi-tive plasma cells was detected in 10 UC cases (IgG4-present, 31%). Although 72 % of IgG4-absent UC patients showed mild disease activity, 70 % of IgG4-present patients showed mod-erate to severe disease activity (p<0.05). Conclusions: UC is sometimes associated with AIP, but it seems that UC is not a manifestation of IgG4-related disease. Infiltration of IgG4-positive plasma cells is sometimes detectable in the colonic mucosa of UC patients and is associated with disease activ-ity. (Gut Liver 2014;8:29-34