Alkaline phosphatase activity of chronic granulocytic leukaemia neutrophils in agar culture.

We measured the concentration of granulocyte-committed progenitor cells (CFU-c) and the alkaline phosphatase activity of neutrophils harvested from colonies cultured from the peripheral blood of 30 patients with high-count chronic granulocytic leukaemia (CGL) in the chronic phase. Neutrophils in colonies cultured from marrow of normal donors or patients with acute myeloid leukaemia in remission served as controls. CFU-c numbers in CGL peripheral blood were on average 3 times higher than in normal marrow (130.1 +/- 126.2 (SD) versus 43.0 +/- 25.2 per 1 X 10(5) cells plated, respectively). The mean NAP scores in cultured CGL neutrophils were substantially higher than control values (89.9 +/- 48.0 versus 55.9 +/- 33.0 units, respectively). There was a tendency for peak values of NA in culture to be reached at earlier points in CGL cultures with high CFU-c numbers (i.e. high proliferative rates) than in those with lower CFU-c numbers (lower proliferative rates). Our data accord with the concept that low NA levels in CGL in vivo result from modulating influences external to the neutrophil.