A functional microRNA binding site variant in IL-23R gene in systemic lupus erythematosus and rheumatoid arthritis: is there any correlation?

Background: IL-23 Receptor (IL-23R) dysregulation has been shown to have critical roles in pathogenesis of different autoimmune diseases including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) via suppression of regulatory T cells (Tregs) as well as differentiation, expansion, and survival of T helper 17 (Th17) cells, followed by upregulation of interleukin 17 (IL-17). Here, we assessed the association of a functional MicroRNAs (miRNAs)-related single nucleotide polymorphism (miR-SNPs: rs10889677) in IL-23R, which was correlated with its overexpression and increased risk for SLE and RA in the Iranian population.

Methods: Genotype and allele distribution of rs10889677 variant were investigated in 105 RA patients, 100 SLE cases and 105 healthy controls via polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method.

Results: Our findings suggested that AA genotype, but not AC genotype, was associated with increased risk of RA (AA vs. CC; OR: 3.27; 95%CI [1.467-7.551]). The allele A was more frequent in RA group compared to controls (A allele vs. C allele; OR: 1.92; 95%CI [1.282-2.894]). This common variant was not significantly correlated with SLE risk in our population (P > 0.05). However, stratification analysis indicated that RA patients with AA genotype show higher serum concentration levels of C-reactive protein (CRP) (P: 0.008). No obvious correlation was noticed between different genotypes in SLE cases, except for a slight difference in terms of oral ulcer manifestation incidence (P: 0.038).

Conclusion: This study suggests a significant relationship between rs10889677 variant in IL-23R with increased risk of RA and some clinical features in RA and SLE patients.

IL-23R gene; Rheumatoid arthritis; Systemic lupus erythematosus; Variant.