Evaluation of IL‐17A, IL‐17F, IL‐23R, VDR, CCL2, CCL5, CCR2, and CCR5 gene polymorphisms and expression in Chinese individuals with syphilis

Abstract Syphilis is a sexually transmitted disease caused by the infection of Treponema pallidum subspecies pallidum. T‐helper type 17–related genes, vitamin D receptor (VDR) gene, and chemokine/chemokine receptor genes are crucial in microbial infection. A total of 16 single‐nucleotide polymorphisms (SNPs) in eight genes (interleukin [IL]‐17A, IL‐17F, IL‐23R, VDR, C‐C motif chemokine ligand [CCL] 2, CCL5, C‐C chemokine receptor [CCR] 2, and CCR5) were analyzed in 188 patients with syphilis and 216 healthy controls. The results showed a strong correlation of IL‐17A rs2275913 (AA vs AG + GG: odds ratio [OR], 1.78; 95% confidence interval [CI], 1.09 to 2.92; P = 0.020; A vs G: OR, 1.33; 95% CI, 1.01 to 1.76; P = 0.043) and rs3819024 (GG vs AA + GA: OR, 1.76; 95% CI, 1.06 to 2.91; P = 0.028; G vs A: OR, 1.36; 95% CI, 1.03 to 1.80; P = 0.030) with syphilis. In haplotype analysis, IL‐17A rs2275913A/rs3819024G showed a risk effect (OR, 1.38; 95% CI, 1.04 to 1.82; P = 0.026), whereas IL‐17A rs2275913G/rs3819024A showed a protective effect (OR, 0.76; 95% CI, 0.57 to 0.998; P = 0.048). The expression levels of IL‐17A messenger RNA (mRNA) in peripheral blood mononuclear cells and IL‐17A secretion in plasma were further examined. No significant differences were found between patients with syphilis and healthy controls. The study also explored whether IL‐17A rs2275913 and rs3819024 were associated with the expression of IL‐17A mRNA and IL‐17A secretion in patients with syphilis. Similar negative results were found. In conclusion, the polymorphisms of IL‐17A rs2275913 and rs3819024 and the haplotype containing these two SNPs influenced the susceptibility to syphilis in a Han Chinese population.