Myeloperoxidases Stains

Cytochemistry

1. Rabab Salama
Clinical and Chemical Pathology Consultant,
HCQM Specialist
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2. Study of chemical elements in
cells.
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4. Substrate +Enzyme >>>>Product
+
Visible product <<<<Chromogen
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5. Types
Myeloperoxidase (MPO)
Leukocyte Alkaline Phosphates (LAP or NAP)
Acid Phosphates, TRAP
Estrase
Sudan Black B stain (SBB)
Iron stain
Reticulinstain
Periodic Acid Schiff (PAS)
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6. PEROXIDASE STAIN
Purpose:
Todifferentiateamyelogenousormonocytic
leukemiafromacutelymphocyticleukemia.
Peroxidaseispresentintheprimaryazurophilic
granulesofneutrophil,eosinophilandmonocyte&
activityincreasedwithmaturation,noactivityis
foundinredcellsorlymphocytes.
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8. PEROXIDASE STAIN
Principle:
Inthepresenceofmyeloperoxidase,H2O2oxidizes
substrate(benzedineorDAB)formingblackppt.
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9. Reagents
Fixatives
Formal ethanol (formaldehyde and absolute
ethanol)
Substrate
Benzedin(carcinogenic) –diaminobenzedine(DAB)
H2O2
Counterstain
Mayer’s hematoxylin
PEROXIDASE STAIN
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10. PEROXIDASE STAIN :
Red –brown peroxidase found in:
neutrophil and eosinophil {promyelocyte–Myelocyte–
Metamyelocyte}
Finely granular staining found in: -Monocyte
Negative stain found in:
( early Myeloblast, lymphblast, basophiles and plasma
cell)
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11. NOTES:
MPO is sensitive to light, smears
should be stained immediately
and stored in dark.
Positive control from healthy
individuals.
Overincubation: false positive
peroxides in RBCs.
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12. Myeloperoxidase (MPO)
bluish-black granules red brown precipitate
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13. Myeloperoxidase stain, bone marrow
aspirate
The red granular staining
peroxidase activity.
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