CD7, CD4 AND, MYELOID ANTIGEN-POSITIVE ACUTE LYMPHOBLASTIC-LEUKEMIA

We report a case of acute lymphoblastic leukemia (ALL, FAB-L2) with un ique cellular characteristics. Leukemic cells were negative for variou s cytochemical stainings except acid phosphatase. Immunophenotypic stu dies revealed CD7+, CD4+, CD8-, CD2+, CD3-, CD13+, CD25+, CD33+ and CD 34+. The immunoglobulin heavy chain and T-cell receptor beta, gamma an d delta chain genes were germline configurations. This patient had a k aryotype of complex abnormalities involving Nos. 5 and 7. Leukemic cel ls showed a prominent response to interleukin-3, granulocyte macrophag e colony stimulating factor (GM-CSF) and G-CSF with partial granulocyt ic differential in a colony assay. A binding assay confirmed the prese nce of both high and low affinity receptors for GM-CSF. These findings suggest that CD7+CD4+CD8-CD3- putative T-cell precursors may retain t he capacity to differentiate to myeloid lineage.