Severity-dependent agalactosylated IgG, associated with enhanced complement activation, has also been observed in IBD patients, is highest in CD and predictive of poor prognosis in UC.46–48 CD patients further exhibit a reduction in IgG sialylation, a modification that promotes anti-inflammatory IgG activity via reduced activating FcγR binding. Here, FCGR2A is linked to inflammatory bowel disease.