IMMUNOPHENOTYPES IN 97 ADULTS WITH ACUTE- LEUKEMIA

Objective. To analyze hematopoietic cell surface antigen reactivity in acute leukemia (AL) by flow cytometry and identify acute mixed-lineag e leukemias (AMLL) employing the most widely accepted criteria. Materi al and methods. Ninety seven patients with de novo AL were studied. Ce ll surface antigens were investigated with monoclonal antibodies direc ted to: B lymphoid (CD10, CD19, CD20, CD21, CD22); T lymphoid (CD2, CD 3, CD5, CD7); and myeloid (CD13, CD14, CD15, CD33, CD41) cell lineages . Maturation cell-associated antigens (CD34, HLA-DR and TdT) were also studied. Results. Twelve patients unclassified by cytomorphology coul d be classified by immunophenotype. Using cytomorphologic, cytochemica l and immunophenotypic data, 54 cases corresponded to acute lymphoblas tic leukemia (ALL) and 43 were acute myeloblastic leukemia (AML). In A LL there were 63% B lineage, 15% T, 7% T/B, 6% undifferentiated and 9% mixed-lineage (coexpression of two or more myeloid-associated antigen s). In AML, myeloid immunophenotype was observed in 86% undifferentiat ed in 2%, and mixed-lineage in 12% (coexpression of two or more lympho id-associated antigens). In addition, 26% of ALL cases and 12% of AML cases expressed a single myeloid and lymphoid antigen respectively. Th e most common aberrant antigens in ALL and AML were CD13 and CD7 respe ctively. The highest frequency of CD34 antigen expression (90%) was de tected in patients with AMLL. Conclusions. Flow cytometric immunopheno typic analysis allowed to: a) establish diagnosis in cytomorphological ly unclassified cases; b) identify AMLL with a frequency similar to th at reported in other series; and c) confirm the heterogeneity of AL.