Place de la cytométrie en flux dans le diagnostic et le suivi des leucémies aiguës

Immunophenotyping has become a mandatory step in the diagnosis of acute leukemias, together with cytomorphologic microscopic examination. It allows to definitely assess the lineage involved in the leukemic process and to precise the stage of blast cells maturation blockade. These features condition in part patients' management, later also influenced by data from cytogenetics and molecular analyses. Proper performance and interpretation of flow cytometry applied to acute leukemias implies solid knowledge of the markers available and their expression in normal bone marrow. These features, long only sparse, now tend to be better and better established, facilitating the initial diagnosis. The prognostic impact of immunophenotypic anomalies has almost disappeared with the progress of therapies, even if definite lineage assessment remains fundamental. However, since criteria of early corticosensitivity (for acute lymphoblastic leukemias) and of initial chemosensitivity appear to be of growing importance in the recent literature, flow cytometry is likely to gain a major place for the follow-up of induction therapies as well as for minimal residual disease assessment at the various treatment checkpoints. This review addresses all these issues.