Clinical Features, Laboratory Characteristics, and Response to Therapy in Patients with Acute Undifferentiated Leukemia

• Published in: Blood 2018-11, Vol.132 (Supplement 1), p.1505-1505
• Main Authors: Harlev, Shimrit, Azoulay, Tehila, Filatov, Margrita, Sarig, Galit, Slouzkey, Ilana
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2018-99-118033

Introduction: Acute undifferentiated leukemia (AUL), also referred to as ambiguous lineage leukemia, has been recognized as a unique entity by the WHO classification of myeloid neoplasms since 2008, and is considered a rare subtype. It is characterized by lacking expression of markers diagnostic of myeloid or lymphoid lineages, and encompasses the provisional entity of myeloid/natural killer (NK) leukemia, which also expresses CD56 and other immature T-cell markers. Small studies have reported that AUL is associated with a poor prognosis; however, cytogenetic and molecular characterization of this subgroup of patients is lacking, as are the long-term outcomes of induction therapy and stem cell transplantation (SCT). The goal of this study was to assess clinical and laboratory data of patients diagnosed with AUL at our institution, focusing on its unique characteristics and response to initial therapy. Methods: Parameters assessed at diagnosis included: initial blood counts, bone marrow (BM) blast cell percentage by morphology, specific phenotypic characteristics of BM blasts, molecular mutations and translocations, as well as cytogenetic abnormalities. Immunophenotyping of BM cells at diagnosis was performed using eight-color flow cytometry. Multi-parameter Cytognos acute orientation tube (ALOT) and the combination of the following antigens were used: CD34/CD117/CD14/CD56/CD36/CD123/HLA-DR/CD45/CD64/CD11c. Data were acquired with FACSCanto II flow cytometer and analyzed with Infinicyt software. Myeloperoxidase staining by fluorescence-activated cell sorting (FACS) was considered negative if