- 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