Upon infection-related or inflammatorystimuli, these leukocytes generate large amounts of H2O2 via Nox2 and release myeloperoxidase (MPO).55 MPO is a hemeprotein that uses H2O2 to oxidize chloride to hypochlorous acid (HOCl) (Figure 1), which is highly cytotoxic.55 HOCl participates in both oxidation and chlorinationreactions. The gene discussed is MPO; the disease is infection.