Association of a miRNA-binding site polymorphism in IL-16 gene with disease risk and clinical characteristics of rheumatoid arthritis and systemic lupus erythematosus

Introduction: /objectives. Single nucleotide polymorphisms (SNPs) located at the 3'-UTR region of the target genes of microRNAs (miRNAs) can dysregulate their expression via disrupting the binding site of miRNAs. Interleukin-16 (IL-16) is involved in the pathogenesis of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). In the current study, we assessed the possible association between rs1131445 polymorphism in IL-16 gene with risk and clinical characteristics of RA and SLE in the Iranian population.

Methods: In this case-control study, 120 patients with RA, 120 patients with SLE, and 120 unrelated healthy subjects were collected to estimate rs1131445 (T > C) polymorphism in IL-16 gene using real-time PCR high-resolution melting (HRM) method.

Results: Our results demonstrated considerable associations between TC genotype and C allele of rs1131445 with enhanced risk of RA (OR_{for TC genotype} = 3.01; 95%CI [1.667-5.526], P < 0.001; OR_{for C allele} = 1.96; 95%CI [1.314-2.941], P < 0.001). Besides, there was a marginal association between CC genotype and increased risk of RA (P: 0.031). However, there was an insignificant correlation between genotypes and allele frequencies of rs1131445 with incidence risk of SLE (P > 0.05). Moreover, stratification analysis indicated that the C allele in rs1131445 was linked with disease activity-associated laboratory parameters such as CRP and ESR in both RA and SLE patients, as well as the higher incidence of neurological symptoms in SLE subjects (P < 0.05).

Conclusion: These results proposed a significant association between IL-16 polymorphism and augmented risk of RA and clinical characteristics of RA and SLE.