The frequency of aberrant lymphoid antigens expression in 202 Iraqi patients with de novo acute myeloid leukemia


BACKGROUND: Immunophenotyping improves both accuracy and reproducibility of acute leukemiaclassification and is considered, particularly useful for identifying acute myeloid leukemia (AML) withlymphoid marker expression. The incidence of the aberrant phenotypes in AML is still controversial;incidences as high as 88% have been reported.OBJECTIVES: To evaluate the occurrence of aberrant lymphoid phenotypes and to correlate theirpresence with various French‑American‑British classification (FAB subtypes), 202 cases of newlydiagnosed AML were analyzed for lymphoid markers CD1a, CD2, CD3, CD4, CD5, CD7, CD8,CD10, CD19, CD20, and CD79a.MATERIALS AND METHODS: Whole blood or bone marrow aspirate of 202 patients with de novoAML was collected in ethylenediaminetetraacetic acid tube and analyzed by flow cytometry using alarge panel of fluorochrome‑labeled monoclonal antibodies. Identification of blast cells was performedusing forward scatter versus side scatter (SSC) parameters and CD45 intensity versus SSC dot plots.An antigen was considered positively expressed when at least 20% of the gated cells expressedthat antigen.RESULTS: Eighty‑five patients (42%) with de novo AML expressed lymphoid‑associated antigens.All AML subtypes demonstrated lymphoid‑associated antigens except M7. T‑cell aberrancy wasthe most common comprising 32.2% of the total aberrancy. The most frequently lymphoid antigenaberrantly expressed was CD7 (25.7%), followed by CD4 (22.4%) and CD19 (7.9%).CONCLUSION: A large number of AML cases showed aberrant lymphoid phenotypes. These lymphoidphenotypes might be associated with different leukemia subtypes. T‑cell markers are more commonthan B‑cell markers. CD7 was the most common lymphoid marker aberrantly expressed in AML.