Role of the Fcgamma receptor IIa polymorphism in susceptibility to systemic lupus erythematosus and lupus nephritis: a meta-analysis.

OBJECTIVE: To assess the impact of the Fcgamma receptor type IIa (FcgammaRIIa)-R/H131 polymorphism on the risk for systemic lupus erythematosus (SLE) and development of lupus nephritis.
METHODS: A meta-analysis was performed based on the Medline and Embase databases (last retrieval August 2001), assessment of bibliographies of pertinent articles, and additional data gathered after contact with primary investigators.
RESULTS: A total of 25 comparisons from 17 studies involving R/H131 genotyping of 1,405 patients with lupus nephritis, 1,709 SLE patients without nephritis, and 2,580 non-SLE controls were included. No association between RR genotype and risk of lupus nephritis relative to both other genotypes (odds ratio [OR] 1.05, 95% confidence interval [95% CI] 0.88-1.27) was demonstrated in the total meta-analysis or in any racial subgroup. The RR genotype was more frequent in SLE patients as a whole (OR 1.30, 95% CI 1.10-1.52) and in SLE patients without nephritis (OR 1.27, 95% CI 1.04-1.55) compared with disease-free controls. A potential dose-response relation between the R131 allele and the risk of SLE was also identified, with an OR of 1.23 for RR versus RH (95% CI 1.03-1.46). The OR was 1.55 for RR versus HH (95% CI 1.21-1.98). There was no significant heterogeneity between racial subgroups. The population-attributable fractions of SLE cases due to the FcgammaRIIa-R131 allele were 13%, 40%, and 24% in subjects of European, African, and Asian descent, respectively.
CONCLUSION: The FcgammaRIIa-R/H131 polymorphism represents a significant risk factor for SLE but has no clear effect on susceptibility for lupus nephritis.