Determination of IL-23 receptor expression and gene polymorphism (rs1884444) in Iranian patients with ankylosing spondylitis

Through investigating genetic variations, it has been demonstrated that single nucleotide polymorphisms (SNPs) in the IL-23 receptor (IL23R) gene have a critical role in the pathophysiology of ankylosing spondylitis (AS). Here, we investigated whether the IL23R variant (rs1884444) is associated with AS in the Iranian population. In this research, we analyzed rs1884444 in a group of 425 patients with AS and 400 matched controls. For DNA extraction, the phenol/chloroform technique was utilized. Peripheral blood mononuclear cells (PBMCs) were obtained from the whole blood of 39 patients and 43 healthy controls and total RNA was extracted. Genotyping was performed by amplification-refractory mutation system (ARMS)–PCR method. Afterward, the expression level of IL23R was analyzed by the real-time quantitative (Q)-PCR method. We observed no significant association between the distribution of alleles and genotypes of rs1884444 and susceptibility to AS. In addition, the expression level of IL23R did not differ between PBMCs from AS patients compared to the control group (P = 0.167). Furthermore, the relative expression level of IL23R was positively correlated with the BASDAI (P < 0.01) and BASFI (P < 0.05) scores of the patients. It appears that IL23R polymorphism (rs1884444) and the level of gene expression might not contribute to the susceptibility to AS in the Iranian population. The correlation of IL23R expression with the level of BASDAI and BASFI scores in patients may be due to the role of the IL-23/IL-23R signaling cascade in inflammation and exert a critical role in the development of AS.