Phorbol myristate acetate-induced neutrophil autotoxicity. A comparison with H2O2 toxicity.

We have previously shown that in the presence of phorbol myristate acetate (PMA), neutrophils kill neoplastic cells as well as themselves. This PMA-induced neutrophil autotoxicity was markedly inhibited by catalase, suggesting that H2O2 directly or indirectly played an important role. In this study we compared PMA and H2O2 toxicity against human neutrophils. The effect of H2O2 was faster and more sensitive to catalase and serum than that of PMA. Sodium azide markedly enhanced the effect of H2O2 but not that of PMA. In contrast, methionine and histidine prevented the toxicity of PMA, while they had no effect on H2O2 toxicity. The results suggest that PMA-induced neutrophil autotoxicity is not mediated by H2O2 alone.