Immunophenotyping parameters as prognostic factors in T-acute leukemia patients

The main aim of this study represents the extension of our studies using multiparametric flow cytometry analysis for exact definition of membrane and intracellular (cytoplasmic and nuclear) markers of acute leukemia cells of T-phenotype. The study of blasts of each patient with all available monoclonal antibodies targeted to T-cell differential antigens and against possible marker coexistence from different lineages has been performed. The main aim was concerned to more proper T-ALL diagnosis and stage definition and identification of the prognostic factors and the useful markers for the follow-up of T-ALL in remission. New knowledge of the T-cell maturation stages of hematopoietic cells in bone marrow and thymus has been applied, as each T-acute leukemia clone is representative of one blocked stage through maturation. We evaluated 44 patients with T-ALL by multiparameter flow cytometry. Patients with more favorable prognosis (i. e. those of cortical stage) could have been already differentiated at diagnosis from those, allocated to pro-T stage, with very immature phenotypes and of an unfavorable clinical course. These patients had very distinctive immunophenotes, CD1a and CD8 markers completely negative, CD7 and cCD3 positive; CD5 was weakly expressed and myeloid markers CD33 and CD13 were coexpressed, or immature markers CD34, HLA-DR were coexpressed, together with myeloid markers CD13 and CD33 of weak positivity. The patients were either completely unresponsive to therapy or because of persistent MRD during continuation therapy, indicated for allogeneic hematopoietic stem-cell transplant. The results have been discussed with similar the most relevant immunophenotypic results of others and mainly with gene-expressing profiling associated with a significantly worse clinical outcome.