Increased leukocyte alkaline phosphatase activity following transfusion of leukocytes from a patient with chronic myelogenous leukemia.

Neutrophils from a patient with chronic myelogenous leukemia and typically low leukocyte alkaline phosphatase (LAP) activity markedly increased in LAP content following transfusion to and circulation in an infected neutropenic recipient. Incubation of the recipient's serum and plasma with normal neutrophils failed to alter their LAP activity. This observation suggests that LAP activity is inducible by as yet unknown "environmental" factors, and possible mechanisms for this are discussed.