Table 1. Flow cytometry-based diagnostic criteria for major acute leukemia subtypes.

Cell surface and intracellular markers used in the diagnosis of acute leukemia are shown, based on the WHO classification system[2]. The immunophenotype of cases with BCL11B SVs is shown at the bottom (“BCL11B deregulated AL”). Note that MPO, which is used to distinguish ETP-ALL from T/myeloid MPAL, is variable in this new subgroup.

Diagnostic entity	Immunophenotypic criteria
AUL	Lack of CD3, CD19, MPO, positive for CD117/CD34, positive for 1–2 of CD13/CD33, frequently CD7 and/or TdT positive
AML	MPO positive and/or positive for multiple markers of myeloid/monocytic differentiation (CD13/CD33/CD11b/CD11c/CD14/CD15/CD64/CD65), negative for cCD3, CD19, often CD117 and/or CD34 positive, variably CD7 positive
T/myeloid MPAL	Myeloid lineage: MPO or at least 2 markers associated with monocytic differentiation (CD11c, CD14, CD64).
	T lineage: strong cytoplasmic or surface CD3
ETP-ALL	cytoplasmic CD3 positive, but CD1a and CD8 negative, CD5 on <75% of blasts, variable for CD2, usually CD117 and/or CD34+, CD13/CD33/CD11b positive, negative for MPO
Typical T-ALL	Surface CD3 positive, CD8 positive, CD5 >75% of blasts, variable for CD34, infrequent for CD13/33/11b, negative for MPO
B/myeloid MPAL	Myeloid lineage: MPO or at least 2 markers associated with monocytic differentiation.
	B lineage: strong CD19 AND at least one of CD79a, cCD22, CD10
Typical precursor B-ALL	Positive for CD19/CD10/CD79a, negative for CD117, frequently CD34+, negative for CD3, myeloid markers
BCL11B deregulated AL	CD117 and/or CD34+, usually cCD3+, always CD2+, always CD5−, always CD8−, variable for MPO, positive for other myeloid markers