FCGR2B and systemic lupus erythematosus: Gut-leakage due to asymptomatic colitis was induced by 60 days of the low dose dextran sulfate solution (DSS)17,18 and the alteration of gut-microbiota was performed by co-housing (together with fecal gavage) with 40-wk-old FcGRIIb−/− mice (symptomatic lupus mice) or age-matched WT control.