Objective: Interferon regulatory factor 5 (IRF5) gene polymorphisms are associated with susceptibility to autoimmune diseases. The aim of this study is to determine the roles of IRF5 single-nucleotide polymorphisms (SNPs) in sarcoidosis.
Methods: A total of 175 Japanese patients with biopsy-proven sarcoidosis and 150 sex-matched controls were genotyped for four IRF5 SNPs: rs729302A/C, rs2004640G/T, rs10954213A/G, and rs2280714G/A. The associations of these SNPs with susceptibility to sarcoidosis were examined.
Results: Carriage of rs10954213A and rs2280714A conferred significant risks for sarcoidosis [carriage of rs10954213A: odds ratio (OR) = 1.96, 95% confidence interval (CI) = 1.15-3.33, P = 0.01, corrected P = 0.04; carriage of rs2280714A: OR = 1.97, 95% CI = 1.22-3.16, P = 0.005, corrected P = 0.02]. The haplotype carrying rs10954213A and rs2280714A (haplotype 2) was significantly associated with susceptibility to sarcoidosis (OR = 2.00, 95% CI = 1.24-3.24, P = 0.004, corrected P = 0.01). rs729302 and rs2004640 were not associated with susceptibility to sarcoidosis, whereas carriage of rs2004640G was protective against pulmonary hypertension (OR = 0.017, 95% CI = 0.002-0.15, P < 0.001, corrected P < 0.001).
Conclusion: A haplotype carrying two functional SNPs of IRF5, rs10954213A and rs2280714A, was associated with the risk of sarcoidosis in the Japanese population.