Association of P2X7R gene polymorphisms with systemic lupus erythematosus in a Chinese population.

The P2X7 receptor is a ligand-gated cationic channel receptor that is actived by ATP and normally expressed by a variety of immune system cells, including macrophages and lymphocytes. Because it leads to release of IL-1β and cell death by apoptosis or necrosis, it is a potential therapeutic target for a variety of autoimmune inflammatory diseases, such as systemic lupus erythematosus (SLE). The P2X7R gene is highly polymorphic, and many single-nucleotide polymorphisms (SNPs) have been detected. A case-control study was performed to investigate the associations of SNPs in the P2X7R gene (rs1718119, rs2230911 and rs3751143) with susceptibility to SLE in 535 Chinese SLE patients and 532 controls. Results showed that rs1718119 was associated with SLE; in particular carriers of the A allele and AA/AG/(AG+AA) genotypes were at lower risk of the disease [A versus G, P < 0.001, odds ratio (OR) = 0.543, 95% CI: 0.424-0.697; AG versus GG, P = 0.018, OR = 0.659, 95% CI: 0.466-0.931; AA versus GG, P = 0.011, OR = 0.176, 95% CI: 0.046-0.668; AG+AA versus GG, P = 0.004, OR = 0.607, 95% CI: 0.433-0.850], but no significant differences in rs2230911 and rs3751143 were observed between SLE patients and controls. Stratification of cases for the presence of nephritis showed that rs2230911 G allele and CG/(CG+GG) genotypes were at a lower risk of SLE with nephritis (LN) (G versus C, P = 0.011, OR = 0.640, 95% CI: 0.454-0.903; CG versus CC, P = 0.035, OR = 0.645, 95% CI: 0.429-0.970; GG versus CC, P = 0.101, OR = 0.349, 95% CI: 0.099-1.228; CG+GG versus CC, P = 0.015 OR = 0.612, 95% CI: 0.411-0.910), but rs1718119 and rs3751143 were not associated with LN. Analysis of the haplotypes revealed one haplotype (ACA) that appeared to be a significantly 'protective' haplotype (P = 0.009, OR = 0.708, 95% CI: 0.546-0.918) with SLE. The findings suggest that the P2X7R gene might contribute to SLE susceptibility in the Chinese population.