The -174/-597 promoter polymorphisms in the interleukin-6 gene are not associated with susceptibility to multiple sclerosis.

Interleukin-6 (IL-6) has been implicated in the etiology of experimental autoimmune encephalomyelitis (EAE) in transgenic animals and contributes to neuropathology in humans. A single nucleotide polymorphism (SNP) at position -174 in the IL-6 gene promoter (IL-6pr) appears to influence IL-6 expression. Complete linkage disequilibrium was observed between the -174 and the -597 alleles. The aim of this study was to investigate the possible influence of -174/-597 IL-6pr polymorphisms on susceptibility to multiple sclerosis (MS). Genotyping of the -597 variant was performed by an RFLP method in 131 MS patients [88 relapsing-remitting (RR-MS), 43 secondary progressive (SP-MS)] and 157 healthy subjects. No differences were found between MS patients and controls with respect to the distribution of -597 IL-6pr genotypes. Neither was found when genotypes were analyzed according to the clinical course of the disease (RR-MS or SP-MS). Future studies focusing on complex transcriptional interactions between the IL-6pr and 3' flanking region polymorphic sites will be necessary to determine the IL-6 haplotype influence on susceptibility to MS.