677C>T and 1298A>C MTHFR polymorphisms affect methotrexate treatment outcome in rheumatoid arthritis

Introduction: Methotrexate (MTX), widely used in the treatment of rheumatoid arthritis (RA), inhibits dihydrofolate reductase and folate-dependent enzymes. Methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism and has been shown to be polymorphic, affecting the enzyme activity. Methods: To examine the association between 677C > T and 1298A > C MTHFR polymorphisms and MTX efficacy in the treatment of RA, a total of 174 RA patients, treated with MTX plus methylprednisone 4 mg and folic acid 5 mg were analyzed. Results: In univariate regression analysis model, the MTHFR 677T allele was associated with significantly higher frequency of remission, whereas in the case of the 1298C allele, a tendency for higher remission rate was observed. In multivariate regression analysis, the presence of both 677T and 1298C alleles was associated with an increased frequency of remission. Conclusion: The results of our study suggest that the MTHFR 677T and 1298C alleles may be associated with an increased rate of RA remission in patients treated with MTX receiving high doses of folic acid supplementation.