Association between interleukin-32 polymorphism and multiple sclerosis

Abstract

Background and aim: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Environmental and genetic factors play a key role in the development of the disease. Interleukin-32 (IL-32) is a cytokine inducing crucial inflammatory cytokines such as TNF-α, IL-6, IL-1β, and MIP-2. The present study was an attempt to reveal any association between IL-32 levels and C/T promoter SNP with susceptibility to MS.

Methods: This case control study recruited a total of 304 subjects including 132 MS patients and 172 sex- and age-matched healthy controls. Clinical and epidemiological characteristics of the RRMS, PPMS, and PPMS populations were assessed. Serum levels and C/T polymorphism of IL-32 were determined by ELISA and RFLP-PCR methods, respectively.

Results: Serum levels of IL-32 were significantly different between MS patients and controls. IL-32 was dramatically higher in the patients than that healthy controls (2297.4±280.2 ver. 712.9±90.2, p=0.001). C allele was prominent in MS patients than the controls and might increase the risk of MS up to 1.6 fold (95% CI; 1.02-2.4, p=0.038). In addition, the presence of C allele enhanced IL-32 production drastically.

Conclusion: This is the first study in which IL-32 gene promoter C/T polymorphism and its serum levels were investigated. The increase in serum levels of IL-32 in accordance with additive effect of the presence of C allele in MS patients might introduce IL-32 as a key player in MS pathogenesis or immunedysregulation.

Keywords: IL-32; Multiple sclerosis; Polymorphism; RRMS; SPMS.