Esterase reactions in acute myelomonocytic leukemia

Area of Science:

• Hematology
• Oncology
• Cytochemistry

Background:

• Acute leukemias are heterogeneous hematologic malignancies.
• Distinguishing subtypes like acute myelomonocytic leukemia (AMML) and acute histiomonocytic leukemia (AHML) is crucial for treatment.
• Esterase activity in leukemic cells can aid in subtyping.

Purpose of the Study:

• To investigate and compare specific and nonspecific esterase reactions in bone marrow cells of patients with untreated AMML and AHML.
• To elucidate the cytochemical characteristics of leukemic cells in these conditions.
• To evaluate the utility of esterase staining in differentiating AMML and AHML.

Main Methods:

• Bone marrow aspirates from 14 untreated AMML patients and 6 AHML patients were analyzed.
• Simultaneous visualization of specific and nonspecific esterase activity was performed on the same cell preparations.
• Alpha-naphthyl acetate was used as the substrate for nonspecific esterase, and naphthol ASD-chloroacetate for specific esterase.

Main Results:

• In AHML, monocytes, monocytoid hemohistioblasts, and undifferentiated blasts showed intense nonspecific esterase activity but no specific esterase activity.
• In AMML, monocytes, monocytoid cells, and granulocytic cells with monocytoid nuclei exhibited both specific and nonspecific esterase activity.
• Polymorphonuclear leukocytes in AMML cases did not show nonspecific esterase activity.

Conclusions:

• The findings support the classification of AMML as a potential variant of acute myeloblastic leukemia.
• Cytochemically, leukemic cells in AMML display characteristics of both granulocytes and monocytes.
• Esterase staining patterns provide valuable insights into the lineage and differentiation of leukemic cells in AMML and AHML.