Cytochemical Stains

Cytochemical Stains :

• cytochemical stains used to classify acute leukemias – myeloid from lymphoid
• usually performed on bome marrow smears
• positive reactions that occur will be associated with a particular lineage
• identify lipids or enzyme within blast population

Myeloperoxidase (MPO)

• strong positives –
  • promyelocytes
  • myelocytes
  • metamyelocytes
  • bands
  • segmented neutrophils
• negative reaction differentiates ALL from AML

Sudan Black B

• stains phospholipids and other intracellular lipids
• negative in lymphocytes
• differentiates ALL from AML
• sensitive for granulocyte precursors

Specific Esterase (naphthol AS-D chloroacetate esterase)

• primary granules of myeloid cells
• myeloblasts, neutophils, basophils, and mast cells stain positive
• eosinophils, monocyes, and lymphocyes stain negative

Nonspecific Esterase (alpha-naphthyl butyrate or alpha-naphthyl acetate esterase)

• buterate – more specific
• acetate – more sensitive
• used to identify monoblasts and monocytes in acute monoblastic leukemia and acute myelomonocytic leukemia

Terminal Deoxynucleotidyl Transferase :

• intranuclear enzyme found in stem cells and immature lymphoid cells within the bone marrow
• not found in mature B lymphocytes