• Involves the activation of the phagocyte NADPH oxidase complex (eg, in neutrophils, monocytes), which utilizes O2 as a substrate.
• O2 (+ NADPH oxidase via oxidative burst) → superoxide (+ superoxide dismutase) → hydrogen peroxide (+myeloperoxidase) → HClO
• H2O2 oxidizes glutathione (from reduced GSH to GSSG)
• Plays an important role in the immune response → rapid release of reactive oxygen species (ROS).
• NADPH plays a role in both the creation and neutralization of ROS.
• Myeloperoxidase contains a blue-green heme-containing pigment that gives sputum its color.
• Phagocytes of patients with CGD lack NADPH oxidase, but can utilize H2O2 generated by invading organisms (except catalase positive organisms) and convert it to ROS.
• Pyocyanin of P aeruginosa generates ROS to kill competing pathogens.
• Oxidative burst also leads to K+ influx, which releases lysosomal enzymes from proteoglycans.
• Lactoferrin is a protein found in secretory fluids and neutrophils that inhibits microbial growth via iron chelation.
• Myeloperoxidase deficiency – usually asymptomatic, increased risk for candidiasis
  • Nitroblue tetrazolium test is normal