The Effects of -806 T/C and -857 T/C Single Nucleotide Polymorphisms in the TNF-α Gene on Rheumatoid Arthritis Severity and Inflammatory Markers

Abstract

Background: Polymorphisms in the TNF-α gene affect the development and progression of rheumatoid arthritis. Objective: To investigate the associations between (-806 T/C) and (-857 T/C) SNPs with rheumatoid arthritis severity and susceptibility in a sample of Iraqi patients. Methods: A case-control study was conducted in Baghdad, Iraq. Twenty healthy controls and 63 patients confirmed to be newly diagnosed with rheumatoid arthritis were included. Those are divided into two groups (patients and controls), and the patients were further subdivided into severe and mild-moderate groups. Samples from those participants were analyzed for clinical and inflammatory parameter measurements. Genotyping by the Sanger method was performed to study the SNPs. Results: No associations were demonstrated between rheumatoid arthritis and polymorphisms at positions -806 and -857. Additionally, there were no differences in the distribution of those SNP genotypes and alleles among the severe and mild-moderate groups. Also, the (-806 C/T) SNP was found to be correlated with DAS 28 in all patients and with hs-CRP in the mild-moderate group. Finally, the -857 C/T SNP was found to be correlated with TNF-α within the mild-moderate group. Conclusions: Polymorphisms at positions -806 and -857 were not associated with rheumatoid arthritis susceptibility, and the CT genotype of -806 C/T SNP was associated with disease activity.