Diagnostic and clinical implications of lineage fidelity in acute leukemia patients undergoing allogeneic stem cell transplantation

We report on a series of five acute leukemia patients who have undergone allogeneic bone marrow transplantation. Initially, these patients were classified as having biphenotypic leukemia; however, subsequent developments in the perception of what constitutes lineage fidelity has resulted in controversy regarding the diagnosis. Flow cytometry and non-random cytogenetic results have had a major impact on redefining the concept of biphenotypic disease. In this report we review the diagnostic dilemma associated with defining acute leukemia lineage fidelity as diagnostic techniques evolve. While our unique focus on the treatment of biphenotypic leukemia patients represents a small population, we verify the single most promising therapy where otherwise the diagnosis is dismal.