No association of polymorphisms in the tumor necrosis factor receptor I and receptor II genes with disease severity in rheumatoid arthritis.

Objective: A recent Italian study found that homozygosity for the G allele of the +196 single nucleotide polymorphism (SNP) of the tumor necrosis factor receptor II (TNFRSF1B) gene was more prevalent in patients with severe rheumatoid arthritis (RA). We investigated whether this particular SNP, and also one at position +36 in exon 1 of the TNF receptor I (TNFRSF1A) gene, are associated with disease severity.

Methods: A group of 181 Caucasian patients with RA was studied. DNA was isolated from patient blood samples and subsequently used to genotype both the exon 1 TNFRSF1A SNP and the exon 6 TNFRSF1B SNP by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. Radiographic damage was measured by the Larsen score, and functional outcome was assessed by the Health Assessment Questionnaire (HAQ). Data were analyzed by multiple regression analysis, with correction for age, sex, and disease duration.

Results: The mean Larsen and HAQ scores did not differ significantly between each of the genotypes from the 2 TNFR SNP. No significant associations between the +36 TNFRSF1A SNP or the +196 TNFRSF1B SNP genotypes and disease severity were found after correcting for age, sex, and disease duration.

Conclusion: Our data suggest that neither the +36 TNFRSF1A SNP nor the +196 TNFRSF1B SNP is associated with RA severity in a population of Caucasian patients with RA.