Methotrexate polyglutamate levels in circulating erythrocytes and polymorphs correlate with clinical efficacy in rheumatoid arthritis

Abstract

Objectives: To measure MTX polyglutamates in circulating erythrocytes (E-MTX), mononuclear cells (MNC-MTX) and polymorphs (PMN-MTX) in rheumatoid arthritis (RA) patients and to see whether these correlated with clinical efficacy and side effects. Methods: Sixty-five patients (40F, 25M; mean age 57 yrs.) with RA (ARA revised criteria) who had been on weekly pulse MTX (2.5 - 37.5 mg) for at least 2 months were entered into this study. The patients were classified as responders (R), partial responders (PR) or non-responders (NR) when blood was sampled for the MTX determination. Side effects since the initiation of MTX were also recorded. MTX-polyglutamates were measured (blinded to clinical det..