TNF-alpha promoter polymorphisms in multiple sclerosis: no association with -308 and -238 alleles, but the -857 alleles in associated with the disease in Turkish patients.

Dysregulation in the expression of pro- and anti-inflammatory cytokines is one of the milestones in multiple sclerosis (MS) development and progression. Tumour necrosis factor (TNF-alpha), a proinflammatory cytokine is believed to play an important role in MS pathogenesis. The objective of this study is to investigate the association between TNF-alpha promoter region (TNF-alpha-238, -308 and -857) and susceptibility to MS and clinical course of the disease. Eighty-six relapsing remitting MS patients and 150 sex-, age- and ethnic-matched controls were enrolled in the study. Genotyping was performed by PCR-RFLP method. We observed a statistically significant increase in TNF-alpha 857 CC genotype in MS patients than controls (P < 0.001) while TNF-alpha 857 CT genotype showed a significant negative correlation with MS patients (P = 0.033). No differences in the distribution of the TNF-alpha-238 and -308 alleles were observed. None of the three polymorphisms (-238, -308 and -857) did not show relation with disease duration, Expanded Disability Status Scale or age of onset. On the other hand, significant difference of TNF -857 CC genotype was identified with the low disease index (P = 0.025). Although the study group is small, the results indicate that TNF-alpha 857 CC genotype may cause susceptibility to MS in the Turkish population.