Clinical Utility of Flow Cytometry Immunophenotyping in Acute Lymphoblastic Leukemia

The acute lymphoblastic leukemia (ALL) is a malignant disease of the immune system and hematologic characterized by accumulation of neoplastic B lymphoid precursors or T (lymphoblasts) in the bone marrow and / or peripheral blood. The diagnosis of these leukemias occurs by morphological classification of French-American-British (L1, L2 or L3) associated with features of immunological profile T or B cell malignancies, based on the expression profile of monoclonal antibodies (MoAb) directed against the antigens of cell differentiation by flow cytometry (FC). Several studies have shown that blast cell immunophenotypes of cases of acute lymphoblastic leukemia does not always exhibit characteristics of lymphoid differentiation normal but exhibit aberrant immunophenotypes. Thus, blasts some cases of acute lymphoblastic leukemia of B lineage may show myeloid or T antigens. Also blasts of cases of acute lymphoblastic leukemia T cell determinants may possess B or myeloid cells.Objective:To determine the immunophenotypic profile by FC in 88 patients with ALL (B or T lineage) diagnosed in the Laboratory of Flow Cytometry Blood Center of Dalton Cunha - HEMONORTE, from State of Rio Grande do Norte, Brazil.Methods:All samples from peripheral blood and / or bone marrow were subjected to FC immunophenotyping using a panel of MoAb specific for diagnosis of acute leukemia (AL) directly conjugated to fluorochromes as fluorescein isothiocyanate (FITC), phycoerythrin (PE), peridinin-chlorophyll protein (PerCP) and allophycocyanin (APC).Results:The patients' age range was between 1 month and 84 years old, with an average of 20.3 years, with 62.5% of the patients being male. The most frequently observed strain was B and the most evident subtype was the Common Pre-B ALL. Among the cell markers evaluated, the most expressed in lineage B were CD19, CD10, HLADR and cCD79a and the antigens most frequently expressed in lineage T were cytoplasmic CD3 (cCD3) and membrane (mCD3), CD7, CD5 and CD2. A small percentage (6.8%) were doubly positive T cells.Conclusion:It is concluded that individuals with ALL in this study have demographic, clinical and immunophenotypic characteristics similar to those observed in other studies, demonstrating that CF immunophenotyping is an essential methodology in the diagnosis of follow-up of these leukemias.