AML - APL:
APL (acute promyelocytic leukemia) blasts often demonstrate high SSC and locate in the granulocytic gate (see figures; blasts in blue) Gating with CD117 in all viable cells is recommended in order to not miss the blast population, which is often not in the conventional blast gate.
Typical immunophenotype for APL:
- CD117+, MPO+, CD13+ (heterogenous), CD33+ (bright, homogenous), CD64+ (most time expressed; variable intensity)
- CD34-, HLA-DR-
CD56 expression associated with worse outcome.
Small subset of cases may show variable CD34 or HLA-DR expression.
Similar immunophenotype can be seen in other acute myeloid leukemia (AML), but immunophenotype in conjunction with high SSC is quite specific for APL.
