IMMUNOPHENOTYPIC CHARACTERISTICS OF THE BLAST CRISIS IN CHRONIC MYELOID-LEUKEMIA

Objective. To characterize the immunophenotype of blast crisis (BC) in Mexican patients with chronic myeloid leukemia (CML). Material and me thods. Mononuclear cells of 17 patients with CML in BC were immunophen otyped employing a panel of 18 monoclonal antibodies: CD5, CD10, CD14, CD22, and anti-HLA-DR used in all patients; CD2, CD15, CD19, CD34, an d CD41 in 13 to 16 patients; and CD3, CD7, CD13, CD20, CD21, CD33, CD4 2b, and CD61 in less than 10 patients. Results. Myeloid was the most f requent type (9/17 cases) followed by lymphoid (6/17) and hybrid or mi xed lineage (2/17). Four of the myeloid BC expressed megakaryocyte/pla telet associated antigens; 5 of 6 cases with lymphoid BC showed an ear ly precursor B cell immunophenotype (HLA-DR+, CD10+), and the other wa s an uncommon case of lymphoid B/T transformation (CD19+, CD5+). The C D34 antigen was present in 6 out of 15 cases: 4 patients with lymphoid BC, 1 with myeloid transformation, and 1 with megakaryoblastic BC. Co nclusions. Our findings are com parable to those found in the literatu re comprising 192 patients. The present study confirms the lineage het erogeneity of CML BC and suggests that extensive immunophenotyping may allow insight for a more precise recognition of normal and leukemic o ntogenesis.