Methotrexate (MTX) in low doses is used in the therapy of rheumatoid arthritis (RA). The aim of many studies is to identify factors predicting the outcome of treatment with methotrexate in rheumatoid arthritis. The action of MTX in RA is associated with the inhibition of inflammatory mediators synthesis. AIF-1 is a cytokine playing a role in chronic inflammatory processes. The levels of AIF-1 were significantly increased in synovial fluid from patients with RA. The aim of this study was to investigate the association between AIF1 gene polymorphisms (rs2269475:C>T, rs2736182:G>A, rs2259571:A>C) and response to treatment of RA patients with MTX.
The study was carried out on 221 patients diagnosed with active rheumatoid arthritis, treated with MTX. Good responders were defined as patients who were receiving MTX and had a DAS28 of ≤2.4 at 6 months.
With regard to the AIF1 rs2259571 polymorphism the remission of RA symptoms was observed in 52.99% of AA genotype carriers, in 45.25% of subjects with AC genotype, and in 32.84% with CC. The differences were statistically significant. CC vs AA p=0.03, OR 0.41, 95%CI (0.18-0.92).
The results of this study suggest that the patients with the rs2259571 CC AIF1 genotype have a poorer response to therapy with MTX.