Leukotriene B 4 metabolism in neutrophils of patients with chronic granulomatous disease: phorbol myristate acetate decreases endogenous leukotriene B 4 via NADPH oxidase‐dependent mechanism

We studied the effect of phorbol myristate acetate (PMA) on endogenous leukotriene B4 (LTB4) metabolism of calcium ionophore A23187-stimulated human neutrophils. Preincubation of normal neutrophils with PMA significantly suppressed the recovery of endogenous LTB4 induced by A23187. PMA did not suppress the recovery of LTB4 produced by neutrophils from patients with chronic granulomatous disease (CGD), which is known to be defective in NADPH oxidase activation to produce reactive oxygen species (ROS). PMA inhibited the formation of omega-oxidation products of LTB4, but enhanced arachidonic acid release in normal and CGD neutrophils. Furthermore, 5-lipoxygenase activity of 10,000 x g supernatants from normal neutrophils pretreated with PMA was equivalent to that of the controls. Decrease in LTB4 recovery was not attributed to the suppression of the intracellular Ca2+ increase. Thus, it is suggested that reactive oxygen species (ROS) produced by PMA may directly affect endogenous LTB4 and convert it into metabolite(s) distinct from omega-oxidation products.