T-Cell Acute Lymphoblastic Leukemia with Severe Leukopenia: Evidence for Suppression of Myeloid Progenitor Cells by Leukemic Blasts

A patient with T-cell acute lymphoblastic leukemia presented with leukopenia due to neutropenia, no circulating blasts and normal hemoglobin level. Marrow leukemic T lymphoblasts inhibited in vitro normal CFU-GM colony growth and released an activity that stimulated normal BFU-E growth. This patient demonstrates that immature T cells may modify hematopoietic stem cell growth both in vitro and in vivo.