Myeloperoxidase (MPO) is a peroxidase enzyme found most amply in neutrophil granulocytes.  Optimal oxygen-dependent microbicidal activity depends on MPO as the critical enzyme for the generation of hypochlorous acid and other toxic oxygen products, which are proposed to contribute to tissue damage during inflammation. It helps to kill microbes by breaking down peroxide in the presence of halide ions, contributing to the bactericidal function of granulocytes. Myeloperoxidase is readily detectable in myeloblasts and immature myeloid cells of acute myelogenous leukemia, progranulocytic leukemia, monomyelocytic leukemia, erythroleukemia, myeloblastomas, and other hematopoietic disorders. Anti-Myeloperoxidase has been utilized for immunophenotyping acute lymphoblastic leukemia in bone marrow biopsies, as part of a panel of antibodies. Anti-Myeloperoxidase staining is also used to aid in the diagnosis of extramedullary leukemia or chloroma. In addition, MPO is thought to be involved in the pathology Alzheimer's disease.