ABSTRACT
Generally, acute leukemias are divided into acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), with a subset of leukemias displaying mixed phenotypic features (acute biphenotypic or bilineal leukemia). AML is a clonal proliferation of immature hematopoietic precursors involving primarily the bone marrow (BM) and blood. The diagnosis and prognosis is most accurately provided by pretreatment assessment of the morphology, immunophenotype, and underlying chromosomal/molecular aberrations. For the purposes of diagnosing acute leukemia, abnormal promyelocytes (APL), monoblasts/ promonocytes (acute monoblastic leukemia), and megakaryoblasts are considered blast equivalents. Immunophenotyping by flow cytometry (FC) plays an important role in the diagnosis, subclassification, and monitoring of patients with acute leukemias the major immunophenotypic characteristics of blasts are presented in chap. Occasional cases of acute monoblastic leukemia with aberrant loss of HLA-DR and CD14 and moderate (not bright) CD45 need to be differentiated from granulocytes displaying dyspoiesis.
