An allotypic variant of Fc gamma RIIa, Fc gamma RIIa-HR (Fc gamma RIIa-R131), has been shown in vitro to reduce the capacity of phagocytic cells to bind and internalize IgG-containing immune complexes. Our aim was to determine whether this allotypic variant was associated with susceptibility to SLE and the development of lupus nephritis, as previous studies have suggested. Fc gamma RIIA genotype analysis was performed by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in 215 Caucasoid, 70 Afro-Caribbean, and 46 Chinese patients with SLE, and in 259,77 and 49 ethnically matched controls, respectively. Distribution of Fc gamma RIIa genotypes between the patients and ethnically matched controls was not significantly different in the three populations studied. No association between the Fc gamma RIIa-HR allotype and nephritis was found. Our results suggest that the Fc gamma RIIa-HR allotype is not a major factor predisposing to the development of SLE, or to lupus nephritis.