FCGR3A and autoimmune thrombocytopenic purpura: Less promising results came from studies correlating FcγRIIa and FcγRIIIa polymorphic variants to IVIG responsiveness and outcome (85): while the high-affinity FcγRIIIa variant 158V is possibly implicated in the pathogenesis of ITP, FcγRIIa (131R), and FcγRIIIA (158V) variants do not seem to impact on chronicity and therapeutic efficacy of IVIG, although studies on such correlations are underway.