Myeloperoxidase deficiency

Myeloperoxidase deficiency is an autosomal recessive genetic disorder featuring deficiency, either in quantity or of function, of myeloperoxidase, an enzyme found in certain phagocytic immune cells, especially polymorphonuclear leukocytes. It can appear similar to chronic granulomatous disease on some screening tests.[1]

Myeloperoxidase deficiency
Other namesMPO deficiency
Hypochlorous acid is normally produced by myeloperoxidase

Presentation

Although MPO deficiency classically presents with immune deficiency (especially candida albicans infections), the majority of individuals with MPO deficiency show no signs of immunodeficiency.

The lack of severe symptoms suggests that the role of myeloperoxidase in the immune response must be redundant to other mechanisms of intracellular killing of phagocytosed bacteria.[2]

People with MPO deficiency have a respiratory burst with a normal nitro blue tetrazolium test because they still have NADPH oxidase activity, but do not form HClO (bleach) due to their lack of myeloperoxidase activity. This is in contrast to chronic granulomatous disease, in which the NBT test is 'negative' due to the lack of NADPH oxidase activity (positive test result means neutrophils turn blue, negative means nitroblue tetrazolium remains yellow).

People with MPO deficiency are at increased risk for systemic candidiasis.[3]

Diagnosis

Treatment

References
  1. Mauch L, Lun A, O'Gorman MR, Harris JS, Schulze I, Zychlinsky A, Fuchs T, Oelschlägel U, Brenner S, Kutter D, Rösen-Wolff A, Roesler J (2007). "Chronic granulomatous disease (CGD) and complete myeloperoxidase deficiency both yield strongly reduced dihydrorhodamine 123 test signals but can be easily discerned in routine testing for CGD". Clinical Chemistry. 53 (5): 890–6. doi:10.1373/clinchem.2006.083444. PMID 17384005.
  2. Levinson, Warren. "Medical Microbiology & Immunology, 8th ed." Lange:2004.
  3. Lehrer RI, Cline MJ (1969). "Leukocyte myeloperoxidase deficiency and disseminated candidiasis: the role of myeloperoxidase in resistance to Candida infection". The Journal of Clinical Investigation. 48 (8): 1478–88. doi:10.1172/JCI106114. PMC 322375. PMID 5796360.
Classification
External resources


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