Objectives: To study -238 and +489 TNF-alpha polymorphisms in severe-unresponsive (more than 6 swollen joints and still active disease despite at least 6 months of DMARDs combination therapy) and mild-responsive (less than 3 swollen joints and good response to MTX or other conventional DMARDs) rheumatoid arthritis (RA).
Methods: We investigated 100 RA patients (56 with severe and 44 with mild disease activity) and 45 healthy blood donors (HBDs). Genotyping was performed by PCR-restriction fragment length polymorphism procedure. Several clinical and serological parameters were also examined.
Results: Severe RA patients disclosed the -238 GG genotype in 100% of the cases versus 95.5% in the mild-responsive patients and 91.2% in the HBDs. The +489 GG genotype disclosed only a trend towards a prevalence in severe RA patients. However the +489 A allele seems to associates with early onset, longer disease duration and longer responsiveness to conventional therapy.
Conclusion: The -238 AG genotype is absent in severe-unresponsive RA, but present in mild-responsive RA subjects. Thus -238 GG homozygosity associates with severity and unresponsiveness. In contrast the +489 polymorphism does not segregate differently between responsive and unresponsive RA patients.