Measures of immunologic and inflammatory responses in vitro in rheumatoid patients treated with methotrexate

We examined the effects of low dose parenteral methotrexate (MTX) on immunologic and inflammatory responses of potential importance in the pathogenesis of rheumatoid arthritis. Only 2 significant changes were noted: the number of esterase positive cells in the peripheral blood decreased, and the uptake of tritiated thymidine by incubated peripheral blood mononuclear cells fell markedly. These changes were present 48 h after an injection of MTX, before decreased disease activity became clinically apparent. We therefore conclude that they were direct effects of the drug itself.