Association of IRF5 gene polymorphisms and lupus nephritis in a Chinese population

Aim: Recently, several studies have provided convincing evidence that polymorphisms in the interferon regulatory factor 5 (IRF5) gene were significantly associated with systemic lupus erythematosus (SLE) in several populations. The aim of this study was to investigate the association between IRF5 and lupus nephritis in a Chinese cohort and analyze the relationship between the rs2004640 genotype and the clinical and pathological phenotypes of lupus nephritis. Methods: The IRF5 rs2004640 polymorphism in a cohort of 190 Chinese lupus nephritis patients and 182 healthy Chinese blood donors was analyzed. The polymorphism examined was genotyped using the TaqMan assay. Results: The IRF5 rs2004640 T allele was associated with the susceptibility to lupus nephritis (rs2004640 T, 41.6% in patients, 30.8% in healthy controls, odds ratio = 1.6, P = 0.002). It was also found that the Chinese population had a much lower minor allele frequency of rs2004640 than Western populations studied to date. In the present cohort, 30.8% individuals in the control group had the detrimental T allele, compared to frequencies in the range of 44-56% that exist in Western populations. No association was found between IRF5 rs2004640 and pathology, or clinical presentation of lupus nephritis in the Chinese cohort examined. Conclusion: The results suggested that the rs2004640 T allele was associated with susceptibility to lupus nephritis and that the IRF5 polymorphism analyzed did not seem to be implicated in the pathology and clinical manifestation of lupus nephritis in the Chinese population.