Role of the Fcγ receptor IIa polymorphism in susceptibility to systemic lupus erythematosus and lupus nephritis: A meta‐analysis

Abstract Objective To assess the impact of the Fcγ receptor type IIa (FcγRIIa)–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 FcγRIIa‐R131 allele were 13%, 40%, and 24% in subjects of European, African, and Asian descent, respectively. Conclusion The FcγRIIa‐R/H131 polymorphism represents a significant risk factor for SLE but has no clear effect on susceptibility for lupus nephritis.