Sex‐specific differences in the relationship between the single‐nucleotide polymorphism rs2298804 of FCER1A and the susceptibility to systemic lupus erythematosus in a Chinese Han population

Summary Background IgE plays a important role in systemic lupus erythematosus (SLE). A recent study identified the high-affinity IgE receptor α-chain (FceRIα) gene FCER1A as a susceptibility locus influencing total serum IgE levels. Aim To investigate whether the single-nucleotide polymorphism (SNP) rs2298804 (251 A>G) of FCER1A is associated with SLE and its clinical characteristics in a Chinese Han population. Methods This case–control study enrolled 948 patients with SLE and 976 healthy controls. Precise phenotyping of patients was accomplished by means of a questionnaire and clinical examination. rs2298804 was genotyped using real-time fluorescence quantitative PCR. Results Compared with the healthy controls, patients with SLE had much lower frequencies of the AG genotype (OR = 0.26; 95% CI 0.194–0.374; P << 0.001) and G allele (OR = 0.45; 95% CI 0.36–0.55; P << 0.001). We also found a stronger association of the FCER1A exon SNP, rs2298804 (A/G), in females (OR = 0.42; 95%CI 0.34–0.53; P << 0.001) compared with males (OR = 0.52; 95% CI 0.28–0.97; P < 0.04). G-allele carriers are less likely to develop SLE than A-allele carriers. Although we did not find any significant correlation between the rs2298804 and the incidence of lupus nephritis, rs2298804 seemed to protect against proteinunia, fever and hypocomplementaemia in patients with SLE, but appeared to be a risk factor for photosensitivity and vasculitis. Conclusions We found that rs2298804 seemed to have a protective effect against SLE in Chinese patients, especially women. It also protected against proteinunia, fever and hypocomplementaemia, but was a risk factor for photosensitivity and vasculitis.