[1512] Immunophenotypic Aberrancies in the Maturing Myeloid and Monocytic Compartment in Acute Myeloid Leukemia by Flow Cytometry

Ying Pei, Jason Schallheim, Guang Fan. Oregon Health & Science University, Portland

Background: Dysplastic morphologic features are commonly present in the maturing granulocytes and monocytes in acute myeloid leukemia (AML). So far, no study has been reported to investigate the immunophenotypic characters in these maturing compartments in AML comparing to the normal individuals by our knowledge. The purpose of this study is to investigate the immunophenotypic aberrancies in the maturing myeloid and monocytic compartment in AML.
Design: We randomly reviewed 34 cases of AML diagnosed in OHSU between 2009 and 2011. The flow cytometry results of bone marrow aspiration were analyzed. Flow cytometry antibody panels include CD71/CD117/CD33/CD13/CD34/HLA-DR/CD16/CD45; CD15/CD64/CD123/CD56/CD34/CD14/CD11b/CD45; CD5/CD10/CD34/CD20/CD19/CD45; CD2/CD7/CD4/CD56/CD5/CD8/CD3/CD45.
Results: Overall 85% of the 34 cases showed immunophenotypic aberrancies in the maturing myeloid and/or monocytic compartments. In the myeloid compartment, the most common finding is decreased or lack of expression of CD10 (56%). Another common aberrancy is expression of monocytic markers including bright CD64 and/or CD14 (23%). Increase of HLA-DR is also observed in 23% of cases, which is followed by the decreased expression of CD16 (21%) and aberrant expression of CD56 (12%), CD123 (9%). In the maturing monocytic compartment, abnormal immunophenotypic findings include aberrant expression of CD 123 (25%) and CD 56 (20%) and dyssynchronous expression of CD14 and CD64. AML transformed CML tends to have normal immunophenotypic features (75%) and only one case shows single aberrancy with down expression of CD10.
Conclusions: In conclusion, immunophenotypic aberrancies are commonly present in the maturing myeloid and monocytic compartments in AML. Most of these abnormal immunophenotypic features have also been reported in the cases of myelodysplastic syndrome, which suggests that maturing compartments in most of AML has immunologic features of dysplastic maturation. The immunophenotypic differences of de novo AML with AML transformed CML also supports pathogenesis differences between them. This may also have prognostic implication, which needs to be answered by future studies.
Category: Hematopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 217, Tuesday Morning


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