Which of the following statements regarding neutrophils are true?

b. Patients with chronic granulomatous disease have a defective neutrophil H-oxidase system

c. Neutrophil killing of bacteria is achieved by oxidants, proteinases and cationic proteins

The neutrophil is a migratory phagocytic cell that defends the host against bacteria and eliminates necrotic tissue. The neutrophil matures in the bone marrow and is released into the circulation as a fully differentiated cell. It is loaded with granules containing a variety of proteinases, hydrolases, antimicrobial agents and cationic proteins. The cell phagocytoses material and the granules fuse with the phagocytic vacuoles to degrade the foreign material. When the cells are challenged with a large amount of material, the granule contents may be released into the extracellular space where damage to surrounding tissue occurs. The neutrophil normally circulates in the human bloodstream for 7 to 10 hours. Thereafter, neutrophils are thought to exist for 1 to 2 days in the tissues before being cleared from the system. Granule constituents are formed during differentiation and replenishment of spent granules does not occur once the cells are in the circulation. Hence, the neutrophil is a fully differentiated end-cell poised to respond rapidly to stimuli, but it is rapidly spent in the process. Neutrophils have a NADPH-oxidase enzyme system on the plasma membrane which can be activated to produce toxic oxygen species including the superoxide anion (02–). Patients with chronic granulomatous disease (CGD) have a defective NADPH-oxidase system in their neutrophils, and are thus unable to generate 02–. Although neutrophils from patients with CGD are able to phagocytose bacteria, they are unable to kill the intracellular microbes and chronic, unresolved infections result.