Fcgamma receptor type IIIA genotype and response to tumor necrosis factor alpha-blocking agents in patients with rheumatoid arthritis.

OBJECTIVE

To determine whether a functional single-nucleotide polymorphism in the gene encoding Fcgamma receptor type IIIA (FcgammaRIIIA) correlates with the response to treatment with tumor necrosis factor alpha inhibitors in rheumatoid arthritis (RA).

METHODS

The study population comprised 282 Swedish patients with RA in whom the therapeutic efficacy of conventional disease-modifying antirheumatic drugs had been insufficient. Infliximab or etanercept treatment was initiated, and patients were evaluated after 3 months, using the American College of Rheumatology 20% improvement criteria (ACR20), the ACR50, and the ACR70 or the European League Against Rheumatism (EULAR) criteria. The chi-square test was used to compare response rates across FcgammaRIIIA genotypes.

RESULTS

No differences in genotype distribution were observed among nonresponders compared with ACR20 responders (P = 0.80), ACR50 responders (P = 0.56), or ACR70 responders (P = 0.91). Similar results were observed when analyzing infliximab and etanercept separately or when using the EULAR response criteria.

CONCLUSION

Unlike the findings of a previous study, the results of the current study suggest that the 158V/F polymorphism of FcgammaRIIIA is very unlikely to influence the clinical efficacy of infliximab or etanercept in patients with RA.