FCER2 and colitis: For example, CD11b-positive B cells expressing high levels of CD21, CD23, IgD, and IgA accumulate in the inflamed colon of mice with DSS-colitis and UC patients, and their adoptive transfer to DSS-treated mice attenuates colitis through a mechanism, which relies on CD11b and appears to be independent on the ability of such cells to influence the gut microbiota (226).