FMO5 and chronic granulomatous disease: In contrast, neutrophil NADPH oxidase has variable effects on pneumococcal strains in vitro; CGD neutrophils have normal killing of pneumococci that produce peroxide, but defective killing of peroxide-deficient mutant strains (Pitt and Bernheimer, 1974; Shohet et al., 1974), suggesting that pathogen-derived reactive oxidants can complement the killing defect in CGD neutrophils.