Fcγ receptor type IIIA genotype and response to tumor necrosis factor α–blocking agents in patients with rheumatoid arthritis

Abstract

Objective To determine whether a functional single‐nucleotide polymorphism in the gene encoding Fcγ receptor type IIIA (FcγRIIIA) correlates with the response to treatment with tumor necrosis factor α 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 FcγRIIIA 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 FcγRIIIA is very unlikely to influence the clinical efficacy of infliximab or etanercept in patients with RA.