CYTOKINE RESPONSIVENESS OF PRIMITIVE PROGENITORS IN ACUTE MYELOGENOUSLEUKEMIA

Long-term cultures (LTC) and immunodeficient (NOD/SCID) mice have been used to quantitate and characterize primitive malignant progenitors f rom patients with acute myelogenous leukemia (AML). In 5-week-old LTC of cells from newly diagnosed patients with AML cytogenetically abnorm al as well as normal progenitors could be easily detected and their nu mbers increased by cytokine supplements to the cultures. Sixty percent of AML samples will engraft in NOD/SCID mouse marrow. The frequency a nd level of engraftment of human cells detected appears to vary among the different subtypes of AML but is not generally affected by treatme nt of the mice with human cytokines. Both the LTC and NOD/SCID mouse a ssay show promise as tools to allow characterization of differences be tween leukemic stem cells which maintain malignant hematopoiesis in in dividual patients and, more importantly, between these cells and their normal stem cell counterparts.