We measured the cyanide-insensitive pyridine nucleotide oxidase activity of fractionated resting and phagocytic neutrophils from 11 normal donors, 1 patient with hereditary deficiency of myeloperoxidase, and 7 patients with X-linked chronic granulomatous disease (CGD). When measured under optimal conditions (at pH 5.5 and in the presence of 0.5 mM Mn++), NADPH oxidase activity increased fourfold with phagocytosis and was six-fold higher than with NADH. Phagocytic neutrophils from patients with CGD were markedly deficient in NADPH oxidase activity.
