Evidence from murine SLE, MRL/1 [20], and BXSB Yaa [21] models identified FcγRIIB as the key inhibitory receptor for several FcγR-mediated immune responses and FcγRIIB-mediated suppression of the aberrant cytokine milieu contributing to SLE phenotypes. Here, FCGR2A is linked to systemic lupus erythematosus.