Association of Fcγ receptor IIb and IIIb polymorphisms with susceptibility to systemic lupus erythematosus in Thais

Abstract

We recently reported association of a newly identified polymorphism of Fcγ receptor (FcγR) IIb, I232T, with systemic lupus erythematosus (SLE) in Japanese. To date, information on FcγR genotypes and their association with SLE is limited in South-east Asian populations. To gain further insight into the role of FcγR polymorphisms in the genetic predisposition of SLE, association of FcγRIIa-H131R, IIb-I232T, IIIa-F176V and IIIb-NA1/NA2 (HNA-1a/1b) polymorphisms with SLE was analyzed in the Thai population, using case-control association analysis. FcγRIIb-232T/T and IIIb-NA2/NA2 genotypes were associated with SLE with the odds ratio of 2.55. Genotype relative risk analysis revealed significant association of IIb-232T/T and IIIb-NA2/NA2, and a tendency of association of the IIIa-176F/F genotype. Moreover, carriers of FcγRIIa-131R were significantly increased in patients with lupus nephritis. Significant linkage disequilibrium was present among FcγRIIb, IIIa and IIIb, and two-locus analyses suggested that the tendency of association of FcγRIIIa could derive from linkage disequilibrium with IIb and IIIb. These results provided evidence that FcγR polymorphisms may be an important predisposing factor also in Thais in a complex manner.