Acetaminophen inhibits the human polymorphonuclear leukocyte function in vitro.

The aim of the study is to investigate the effect of Acetaminophen (Am) on the oxidative respiratory burst of isolated human polymorphonuclear leukocytes (PMNs). Acetaminophen inhibited the luminolchemiluminescence (CL) peak response of PMNs stimulated with phorbol myristate acetate (PMA) or opsonized zymosan in a concentration dependent manner. The inhibitory effect of Am on PMA-stimulated PMNs-CL response was partially reversible. The level of CL inhibition with Am plus the hydroxyl radical scavengers allopurinol, dimethyl sulfoxide (DMSO) or superoxide dismutase (SOD) is greater than that with Am alone. Generation of superoxide (O2-) by stimulated PMNs, as assayed by superoxide dismutase inhibitable reduction of Ferricytochrome c, was markedly inhibited by Am. Furthermore, the phagocytic activity of PMNs as tested for by the ingestion of opsonized dead yeast was significantly reduced in Am-treated cells. These results indicate clearly that Am causes significant inhibition of the human PMNs function in vitro.