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How does chronic granulomatous disease affect phagocytic cells?

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immune system disorder False-color scanning electron micrograph of a T cell infected with HIV (human immunodeficiency virus), the agent that causes AIDS (acquired immunodeficiency syndrome).

In individuals with chronic granulomatous disease (CGD), phagocytic cells—such as neutrophils and macrophages—are unable to effectively destroy invading microorganisms. While these cells retain the ability to perform phagocytosis by engulfing pathogens, they suffer from a critical genetic defect that prevents them from killing the ingested microbes.1

Normally, phagocytes utilize a process known as the respiratory burst to eliminate pathogens. This involves a significant increase in oxygen consumption and the production of toxic compounds, such as hydrogen peroxide and hypochlorite, which are lethal to bacteria and fungi. In CGD, a mutation in the components of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzyme complex prevents the cell from manufacturing these essential antimicrobial substances.12

Because the phagocytes cannot produce the oxidative agents required to neutralize the pathogens they have engulfed, the microorganisms survive and proliferate, leading to recurrent, severe infections and the formation of inflammatory masses known as granulomas.12