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a hemoprotein having peroxidase activity, occurring in the primary granules of promyelocytes, myelocytes, and neutrophils, and that exhibits bactericidal, fungicidal, and viricidal properties.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


(mī'ĕ-lō-per-oks'i-dās), [MIM*606989]
A peroxidase occurring in phagocytic cells that can oxidize halogen ions (for example, I-) with hydrogen peroxide to the free halogen, also producing two water molecules; an autosomal recessive deficiency of myeloperoxidase leads to impaired bacterial killing; formerly called verdoperoxidase because it is green. Compare: verdoperoxidase.
Farlex Partner Medical Dictionary © Farlex 2012


A gene on chromosome 17q23.1 that encodes myeloperoxidase during myeloid differentiation. MPO is the major component of neutrophil azurophilic granules and produces hypohalous acids (e.g., hypochlorous acid) and other toxic intermediates central to the microbicidal activity of netrophils.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
References in periodicals archive ?
Myeloperoxidase is associated with incident coronary heart disease independently of traditional risk factors: results from the MONICA/KORA Augsburg study.
It has been shown that the interaction between NO and myeloperoxidase (MPO) could have a profound effect on the toxic capacity of neutrophils (Brunet, 2001; Knaapen et al., 2005).
Immunohistochemical staining was extremely useful in clarifying diagnosis of KFD, as most cells were CD68-positive histiocytes that coexpressed myeloperoxidase. In addition, clusters of plasmacytoid dendritic cells, highlighted by CD123, were seen (Figure 4, D through F).
Assessment of myeloperoxidase activity in whole rat kidney.
We could not detect any correlation between c-IMT with plasma myeloperoxidase. Even though myeloperoxidase is an important enzyme related to inflammation, cardiovascular disease, and uric acid oxidation (9), it is not the only peroxidase present in plasma and is likely not the solely responsible for uric acid oxidation in plasma.
Suicidal NETosis is regulated by NADPH, myeloperoxidase, and elastase and is induced by microorganisms and chemical agents such as PMA [1,6,7].
(b) High-power view of myeloperoxidase stain highlights cytoplasmic staining of lesional cells.
In flow cytometric analysis, myeloblasts expressed CD34, HLADR, CD117, CD13, and myeloperoxidase. Although a cytogenetic abnormality due to significant dysplastic morphology was expected in his bone marrow, conventional cytogenetics, FISH, and mutational analyses reported normal karyotype.
Immunological tests showed an antinuclear antibody ratio of 1: 160 with a speckled pattern, anti-SSA/Ro antibody 1: 16, rheumatoid factor 123.9 IU/mL (<15), positive direct Coombs test, and myeloperoxidase (MPO)-ANCA 129 U/mL(<3.5), whereas the tests for cryoglobulin, anti-hepatitis C, anti-aminoacyl transfer RNA synthetase, anti-double-strand DNA, anti-RNP, anti-Sm, anti-SSB/La, and anti-phospholipid antibodies were all negative.
Immunohistochemistry showed strong myeloperoxidase positivity in the atypical cells, confirming a diagnosis of granulocytic sarcoma (Figure 1b).
In both the cells and blood, there was evidence of myeloperoxidase, or MPO, an enzyme expressed by a type of white blood cell which, at high levels in the blood, has been linked to stiff blood vessels, oxidative stress and heart attack in humans.