All of the following are disorders of phagocyte function, except:
High-Yield Explanation
X-linked Severe Combined Immunodeficiency (SCID): most common form of SCID, mutation in the common g-chain (gc) subunit of cytokine receptors, defect in T-cell development, T-cell numbers are greatly reduced, B cells may be normal in number, antibody synthesis is impaired. Chronic granulomatous disease: Decreased oxidative burst due to defect in phagocyte oxidase, can be X-linked (majority) or autosomal recessive, macrophage-rich chronic inflammatory reaction seen due to inadequate neutrophil response. Chediak-Higashi syndrome: autosomal recessive, defect lies in fusion between phagosome and lysosome (impaired bacteriolysis), occurs due to mutation in LYST gene (defective transpo of materials into lysosomes), neutropenia, defective degranulation, and delayed microbial killing. Myeloperoxidase deficiency: Decreased microbial killing because of defective MPO-H2O2 system after phagocytosis of microbes.