CELLULAR CHARACTERISTICS OF ACUTE-LEUKEMIA CELLS SIMULTANEOUSLY EXPRESSING CD13 CD33, CD7 AND CD19/

Of 832 acute leukemia patients, including 580 acute myeloblastic leuke mia (AML), 197 pre-B acute lymphoblastic leukemia (ALL) and 55 pre-T A LL, 26 cases (3.1%) of CD13/CD33(+) CD7(+)CD19(+) acute leukemia were found. A total of 20 patients were diagnosed as AML, two as pre-B ALL and four as pre-T ALL. Based on the relative intensity of expression o f CD7 and CD19, CD13/CD33(+) CD7(+)CD19(+) acute leukemia patients wer e subclassified into three categories. Type I (CD7 > CD19) included te n AML and four pre-T ALL, having cellular characteristics similar to C D7 + AML and CD13/CD33(+) CD7(+) ALL. Type II (CD7 < CD19) consisted o f four AML with t(8;21) and two pre-B ALL. Type III (CD7 = CD19) inclu ded six AML. CD13/CD33(+)CD7(+)CD19(+) acute leukemia frequently expre ssed stem cell associated molecules, such as CD34 (88.5%), HLA-DR (96. 2%) and mRNA for MDR1 (72.2%), GATA-2 (87.5%) and SCL (25.0%). Simulta neous expression of cytoplasmic CD3 and myeloperoxidase in some leukem ia cells implies that CD13/CD33(+)CD7(+)CD19(+) acute leukemia cells h ave the potential to differentiate into various lineages. These data s uggest that a small population of acute leukemia patients with distinc t phenotype, CD13/CD33(+)CD7(+)CD19(+) acute leukemia, may originate f rom hematopoietic stem cells. (C) 1997 Elsevier Science Ireland Ltd.