Interleukin 18 Polymorphisms and its serum level in Patients with Multiple Sclerosis

BACKGROUND: Multiple sclerosis (MS) is a chronic demyelinating disorder of central nervous system. Although the definite pathogenesis of MS has not been understood, crucial role of environmental and genetic risk factors has been proposed. PROPOSE: To determine the serum level of interleukin-18 (IL-18) as well as gene polymorphisms of IL-18 (rs1946518, rs360719, and rs187238). METHODS: In this case–control study, 110 MS patients diagnosed according to the McDonald criteria and 110 healthy individuals were recruited. IL-18 gene polymorphisms were genotyped by polymerase chain reaction high-resolution melt test, and IL-18 serum level was determined by enzyme-linked immunosorbent assay technique. RESULTS: The mean age of the MS patients (89 females and 21 males) and the control group (89 females and 21 males) was 30.3 ± 9.25 and 30.28 ± 9.13 years, respectively. The mean serum levels of IL-18 in MS patients and healthy individuals were 341.56 ± 39.22 Pg/Ml and 146.52 ± 29.30 Pg/Ml, respectively (P < 0.001). The genotype of rs1946518 (but not rs360719 and rs187238) was significantly different between groups (P = 0.037 and P = 0.069, respectively). CONCLUSION: In this study, we showed the significant higher IL-18 serum level and significant different frequencies of two polymorphisms of IL-18 in MS patients. These results show the important roles of IL-18 in MS pathogenesis. However, more studies are needed to verify our results in larger sample size.