Tumor necrosis factor beta (TNF-β) NcoI polymorphism is associated with multiple sclerosis in Caucasian patients from Southern Brazil independently from HLA-DRB1

Abstract

This study evaluated the association of tumor necrosis factor beta (TNF-β) NcoI polymorphism with the presence of multiple sclerosis (MS), disability, and HLA-DRB1 alleles in 208 Brazilian MS patients. As controls, 147 healthy individuals were included. The disability was evaluated at baseline and 5-year follow-up using the Expanded Disability Status Scale (EDSS). The TNF-β genotypes were determined using PCR and restriction fragment length polymorphism and serum TNF-α level was determined using enzyme-linked immunosorbent assay. Among the MS patients, 166 (79.8%) were white, 39 (18.7%) were brown, and three (1.4%) were Asiandescents (those were excluded from the further analysis). Among the 205 MS patients, 149 (72.6%) presented remitting-relapsing MS. The baseline and 5-year follow-up EDSS ranged from 0.0 to 3.0 and from 1.0 to 5.7, respectively. The TNFB2/B2 genotype was associated with the presence of MS among the white patients (p = 0.0443). Brown patients presented higher disability (p = 0.0234) and higher TNF-α levels (p = 0.0463) than white patients. White and brown patients carrying TNFB2/B2 genotype exhibited higher TNF-α levels (p = 0.0354 and p = 0.0309, respectively)than those with other geotypes. Association between TNF-β NcoI genotypes and HLA-DRB1 alleles was not observed among the MS patients (p > 0.05). Taken together, TNFB2 allele was associated with the presence of MS independently of HLA-DRB1 in white patients and the TNFB2/B2 genotype was associated with increased TNF-α levels in white and brown patients, which could be an important genetic factor candidate for the susceptibility and pathogenesis of MS.