APPENDICECTOMY, PRIMARY SCLEROSING CHOLANGITIS (PSC) and ULCERATIVE COLITIS (UC)
It is shown that appendicectomy has a strong negative association with UC and a more benign UC phenotype and PSC, and removal of an appendix in patients who are susceptible to UC may predispose to a more innocuous UC phenotype.
Abstract
The relationship between PSC and inflammatory bowel disases (IBD) remains largely unexplained. The most usual IBD phenotype reported with PSC is clinically mild UC pancolitis. Primary sclerosing cholangitis is not improved by colectomy (+ contemporaneous appendicectomy). We have shown that appendicectomy has a strong negative association with UC and a more benign UC phenotype. In animal models, early appendicectomy results in a significant reduction in mucosal Ig production, and in models of colitis the same early intervention protects the animal from the disease. The human appendix has a large complement of activated B cells which may seed the intestine with IgA‐secreting plasma cells in a similar way to these models. IgA will exclude bacteria from the gut epithelium. If there is impaired IgA‐mediated bacterial exclusion, then there may be not only a diluted intestinal mucosal immune response but an increased bacterial load in the portal circulation that requires a second‐line immune response by the liver. Thus, removal of an appendix in patients who are susceptible to UC may predispose to a more benign UC phenotype and PSC.