Comparing the type and severity of inflammatory bowel disease in relation to IgG4 immunohistochemical staining

Background and study aim : The role of immunoglobulin (Ig) G4 in the etiopathogenesis of inflammatory bowel disease (IBD) and its association with endoscopic and pathological activity are not yet completely understood. The purpose of this study was to determine the possible relationship between IgG4 status and IBD. Patients and methods : Endoscopic colon biopsies of 55 patients with ulcerative colitis (UC) and of 17 patients with Crohn's disease (CD) were examined. Numbers of IgG4-positive plasma cells stained immunohistochemically were counted in a minimum of 5 high power fields (HPFs) for each specimen. The presence of > 10 cells/HPF IgG4-positive PCs was considered positive. Results : The prevalence of IgG4-positive plasma cells in the lamina propria of the colonic mucosa was significantly higher in patients with UC than in those with CD (p :0.01). Additionally, the prevalence of IgG4-positive plasma cells increased in line with en- doscopic and pathological activity in UC patients. Conversely, we determined no significant correlation between IgG4 positivity and pathological activity in the CD group. IgG4-positive UC patients also exhibited findings of more severe disease compared to IgG4- negative UC patients. Conclusions : Immunohistochemical IgG4 staining may predict disease severity in UC and may be a useful marker for distinguish- ing between UC and CD. (Acta gastroenterol. belg., 2016, 79, 216- 221).