Inflammatory bowel disease (IBD) is a series of intestinal nonspecific inflammatory conditions, comprising of predominantly ulcerative colitis (UC) and Crohn’s disease (CD). Although the pathogenesis considered are multifactorial involving genetic predisposition, epithelial barrier defects, dysregulated immune responses and environmental factors but still it is not clear. There is evidence that T lymphocytes are involved in UC, but role of B cells remains unclear. The roles of IgG4-expressing plasma cells in the pathogenesis of UC is obscure. However, IgG4 was earlier regarded as a noninflammatory antibody. We hypothesized that colonic biopsies with increased numbers of IgG4-positive plasma cells might be restricted to ulcerative colitis.