Inhibition of neutrophil chemotaxis in methotrexate-treated rheumatoid arthritis patients.

Polymorphonuclear cell (PMN) chemotaxis was assessed using the in vitro under agarose assay in ten rheumatoid arthritis patients prior to and following a single 10-mg dose of methotrexate (MTX). PMNs obtained from patients after MTX showed a decreased chemotactic migration response to both zymosan activated serum (P less than 0.005) and N-formyl-L-methionyl-L-phenylalanine (P less than 0.01). In similar conditions, no significant difference in chemotactic migration could be detected in six rheumatoid arthritis patients not on MTX. In contrast to the in vivo effects of MTX, there was no inhibition of normal PMN chemotactic migration following a 30-min in vitro incubation of the cells with MTX (P less than 0.99).