Modulation of phagocytosis and bactericidal activity of human polymorphonuclear and mononuclear phagocytes by antiarthritic agents.

The influence of 9 antiarthritic drugs on phagocytosis and intracellular bactericidal activity of human polymorphonuclear (PMN) and mononuclear phagocytes was investigated using gram-positive and -negative microorganisms and latex particles. With the exception of prednisone all the other agents suppressed phagocytosis and/or phagocytic index of PMN. Whereas naproxyn suppressed phagocytosis of all 3 particles used, other drugs had more pronounced inhibitory activity on phagocytosis of E. coli than of S. aureus or latex particles. Monocytes were less influenced by antiarthritic agents. Intracellular bactericidal activity was markedly suppressed by phenylbutazone, oxyphenbutazone, naproxyn and gold sodium thiomalate. In suboptimal conditions when serum was omitted from the assay, dual action of some drugs was observed. It may be concluded that antiarthritic agents may modulate phagocytosis and intracellular bactericidal activity. The modulation was most pronounced in conditions similar to those in vivo i.e., with added serum and when the cells were exposed to antiarthritic agents for longer time. It should be taken into consideration while assessing defense mechanisms and susceptibility to infection in rheumatic diseases.