FCGR2B and lupus nephritis: Indeed, the immune-complex deposition in the GI tract during the active lupus nephritis without the observed clinical GI abnormalities (diarrhea or weight loss) in the lupus rodent model from the deletion of Fc gamma receptor IIb (FcgRIIb-/- mice) [26,27] with the defects on intestinal tight junctions (Figure 1) are demonstrated.