Surface marker analysis in acute myeloid leukaemia and correlation with FAB classification

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Acute myeloid leukemia (AML) classification traditionally relies on morphology (FAB criteria).
• Immunological phenotypes of blast cells offer additional discriminatory potential.
• Understanding AML heterogeneity is crucial for accurate diagnosis and treatment.

Purpose of the Study:

• To analyze the immunological phenotype of AML blast cells.
• To correlate immunological findings with the French-American-British (FAB) classification.
• To propose a novel immunological classification for AML.

Main Methods:

• Analysis of blast cell immunophenotypes in 102 AML patients using 20 monoclonal antibodies and terminal deoxynucleotidyl transferase (TdT) enzyme.
• Correlation of immunological data with established FAB morphological classification.
• Identification of specific antigen expression patterns for different AML subtypes.

Main Results:

• Partial correlation observed between FAB classification and immunological phenotypes; however, significant overlap exists.
• M1 and M5a AML showed undifferentiated phenotypes; M3 exhibited a uniform My7+, Ia-, FMC8+ phenotype.
• CDw14 expression increased in M5b vs. M5a; Glycophorin-A present in M6; TdT activity found in 10% of cases, higher in monocytic variants.

Conclusions:

• Immunophenotyping provides valuable insights into AML heterogeneity beyond morphological classification.
• Specific phenotypes identified for M3 and M6 subtypes, and variations in M4/M5.
• The study confirms the need to include megakaryoblastic leukemia within AML and proposes a potential immunological classification.