Characterization of leukaemic basophil progenitors from chronic myelogenous leukaemia

Summary We describe the unique characteristics of leukaemic basophils from a patient with chronic myelogenous leukaemia (CML). The leukaemic cells were immature basophil‐like blasts and expressed CD4, CD7 and HLA‐DR in addition to CD13 and CD33. Both immunoglobulin and T cell receptor genes were retained in germline configurations. Interleukin‐1 (IL‐1) or granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) as well as IL‐3 or IL‐4 enhanced the proliferation and differentiation of leukaemic cells and only basophils were generated from in vitro culture. These results suggest that basophil progenitors expressing CD4, CD7 and HLA‐DR may be involved in the development of basophilic crisis of CML and that both IL‐1 and GM‐CSF may act on basophil progenitors as well as IL‐3 or IL‐4.