Impact of genetic polymorphisms in the interleukin-18 and interleukin-21 genes on the risk and clinical outcomes of multiple sclerosis.

BACKGROUND

This study was designed to investigate the association of IL-18-137G/C (rs187238) and IL-21-1472G/T (rs2055979) single nucleotide polymorphisms (SNPs) with the risk of MS, the disease progression, and related clinical features.

METHODS

In this study, 271 Egyptian individuals participated, including 131 MS cases (relapsing-remitting (RR-MS) cases [N = 99], and progressive MS cases [N = 32]) and 140 unrelated healthy controls. The association between IL-18-137G/C (rs187238) and IL-21-1472G/T (rs2055979) single nucleotide polymorphisms (SNPs) and the risk of MS and the disease progression, as well as the clinical features including the disability progression and the severity, were analyzed by using polymerase chain reaction (PCR) methods.

RESULTS

The GC genotype and C allele of the IL-18 SNP were linked to susceptibility to MS, and the genotypic forms (GC and CC genotypes) and allelic form (C allele) were linked to an elevated risk of the development of progressive MS. Regression investigation further strengthened the notion that this SNP is a predictor of the disability of the disease according to the Disability Status Scale (EDSS) values. For the IL-21-1472G/T SNP, the TT genotype and T allele in the Egyptian cohort were related to the reduced risk of progressive MS when comparing the two diseased forms; however, they were not associated with the disability progression and severity of the disease.

CONCLUSION

The IL-18-137G/C SNP might be a possible risk determinant of the susceptibility as well as the progression of MS. In contrast, the IL-21-1472G/T SNP could protect against progressive MS.