Effect of aurothiomalate on human mononuclear blood cells cultured in vitro.

Human mononuclear phagocytes were exposed to aurothiomalate in various concentrations and at various stages in the differentiation from monocytes to macrophages in vitro. Monocytes exposed to aurothiomalate during the first 90 minutes of culture showed impaired engulfment capacity when tested 8 days after the exposure to the drug. It was found that aurothiomalate suppressed the digestion capacity in differentiated macrophages while the engulfment capacity was unaffected by the drug. During the period of differentiation from 90 minutes to 8 days of culture, exposure to aurothiomalate resulted in a dose dependent reduction in cell survival and differentiation. The effect of aurothiomalate on the blastoid transformation of lymphocytes following BCG stimulation was also tested. A strong and dose dependent inhibition of DNA synthesis was recorded. The inhibition of phagocytosis in mononuclear phagocytes and the inhibition of antigen-induced lymphocyte stimulation as demonstrated may help to explain the effect of aurothiomalate in patients suffering from rheumatoid arthritis.