Th17 pathway genes polymorphisms in Algerian patients with systemic sclerosis

TH17 cells have involved in the pathogenesis of several autoimmune diseases including systemic sclerosis (SSc). The aim of our study was to investigate an association of IL-17A, IL-17F, IL-21, IL-23R and STAT3 genes with SSc susceptibility, and clinical and immunological phenotypes.

The case-control study included 136 patients suffering from SSc and 317 healthy controls of the Algerian population. Eight single nucleotide polymorphisms (SNP) of genes encoding TH17 pathway were genotyped using TaqMan allelic discrimination assays. These SNPs are: IL-17A (rs2275913), IL17F (rs2397084 and rs763780), IL-21 (rs6822844), IL-23R (rs10489629, rs11209026 and rs1343151) and STAT3 (rs2293152).

The current study showed a significant association of rs2397084 SNP (p = 0.049 and p = 0.036 for the TT genotype and the T allele, respectively) and rs6822844 SNP (p = 6.6ₓ10-4 for the G allele) with systemic sclerosis (SSc) susceptibility. Also, we found an association of rs2275913 SNP (pc = 0.015 and p = 0.005 for the GG genotype and the G allele, respectively) and rs6822844 SNP (pc = 0.024 for the TT genotype) with digestive involvement. Also an association with anti RNAPIII antibodies production have been found with rs6822844 SNP (pc = 0.012 and pc = 0.029 for the GT genotype and the T allele, respectively). Association of rs10489629 SNP with digital infarcts (p = 0.043 for the C allele), interstitial lung disease (p = 0.045 for the CT genotype) and anti SSA antibodies production (p = 0.001 and p = 0.008 for the CT genotype and the T allele, respectively) have been showed. Finally an association of rs1343151 SNP with digital infarcts (p = 0.028 for the A allele), and with interstitial lung disease (p = 0.025 for the AG genotype) have also been found.

The study revealed that IL-17F and IL-21 genes were associated with systemic sclerosis (SSc) susceptibility and that IL-17A, IL-17F, IL-21 and IL-23R genes influence the clinical and immunological features, which suggest the implication of TH17 cells in SSc pathogenesis.