Interaction of miR-181b and IFNA1 Polymorphisms on the Risk of Systemic Lupus Erythematosus.

Introduction. A previous work has discovered that chromosome 1q32 locus linked to the risk of systemic lupus erythematosus (SLE) and miR-181b located on the susceptibility site with downregulation inversely correlating to its target molecular interferon alpha 1 (IFNA1). The purpose of this study was to investigate the association of miR-181b and IFNA1 polymorphisms with IS risk. Methods. The miR-181b rs322931, IFNA1 rs1332190, and rs10811543 were genotyped using a Multiplex SNaPshot assay. miR-181b expression levels in plasma of SLE patients and controls were analyzed using quantitative PCR. Results. The rs322931 CT, CT/TT, and T allele exerted an increased trend of SLE risk (CT vs. CC: adjusted OR=1.71, 95% CI 1.16-2.50, P=0.01; CT/TT vs. CC: adjusted OR=1.45, 95% CI 1.08-1.95, P=0.01; T vs. C: adjusted OR=1.38, 95% CI 1.07-1.79, P=0.01). Combined genotypes of the rs322931 CT/TT+rs1332190 TT and the rs322931 CC+rs10811543 AG/AA also revealed an increased risk of SLE. Gene-gene interaction analysis showed that a three-locus model consisting of rs322931, rs1332190, and rs10811543 attributed an increased risk of SLE. Further genotype-phenotype analysis revealed that rs322931 CT/TT carriers displayed lower levels of miR-181b. Conclusions. These findings indicate that the miR-181b rs322931 may be singly and jointly responsible for the etiology of SLE by altering miR-181b expression.