An Extrinsic Factor Controls Neutrophil Alkaline Phosphatase Synthesis in Chronic Granulocytic Leukaemia

Abstract

S ummary The mechanism underlying the reduced neutrophil alkaline phosphatase (NAP) activity in chronic granulocytic leukaemia (CGL) has been investigated by in vivo manipulation of CGL neutrophils. These cells, which had almost no alkaline phosphatase activity following collection by leucapheresis, had greatly elevated activities 14–17 h after transfusion into three neutropenic recipients. It is postulated that NAP synthesis in mature neutrophils is controlled by an extrinsic factor and that the levels of this factor is reduced in patients with CGL with high neutrophil counts.