Impact of immunophenotyping on management of acute leukemias.

BACKGROUND AND OBJECTIVE The diagnosis of acute leukemias (AL) requires a multiparametric approach in order to apply risk-adapted therapeutic protocols and appreciate the potential outcome of any given patient. Blast cells immunophenotyping is a key test in this issue, yet the information provided by immunophenotyping has become staggering, and it may be difficult to identify relevant characteristics clearly. This manuscript provides a critical review of the literature regarding the importance of immunophenotyping in acute leukemia diagnosis and management. DATA SOURCES AND METHODS The information given here is based on the experience of the authors, on their literature files and on additional material retrieved through articles and reviews covered by the Institute for Scientific Information (ISI) and the Medline database. Studies with proper definition of the patients and sufficient information regarding follow-up were considered. RESULTS Immunophenotyping allows an early confirmation of AL diagnosis and establishes lineage assignment. Adequate and comprehensive panels of monoclonal antibodies also allow detection of aberrant immunophenotypic profiles of prognostic value or of use in detecting minimal residual disease. A number of unusual immunophenotypic features are also associated with prognosis. The development of new antibodies, new insights in the functional properties of differentiation antigens, and the quantimetric approach of immunophenotyping will keep this field changing. Moreover, as therapeutic protocols evolve, some earlier results need to be reconsidered. INTERPRETATION AND CONCLUSIONS Immunophenotyping, together with cytologic, karyotypic and molecular approaches, retains a crucial place in the diagnosis and management of acute leukemias. It remains a rather specialized approach and should be interpreted in a multidisciplinary perspective, considering for each patient the idiosyncrasies possibly relevant to prognosis.