Failure of chronic-granulocytic-leukaemia leucocytes to release an inhibition of granulopoiesis.

Phagocytosing, but not resting, neutrophils normally release an inhibitor of in-vitro granulopoiesis which suppresses the production or release of colony-stimulating factor by monocytes and macrophages. Neutrophils from 12 patients with chronic granulocytic leukaemia (CGL) were found to contain the inhibitor, but in 11 of the 12 patients there was failure to release significant amounts during phagocytosis. It is suggested that such a defect in the feedback control of granulopoiesis could lead to the progressive inappropriate accumulation of morphologically normal granulocytes, as seen in CGL.