Absolute alkaline phosphatase positive and negative neutrophil counts in chronic granulocytic leukemia

Absolute counts for the alkaline phosphatase positive (AP+) fraction of potentially AP+ neutrophils were measured cytochemically during the course of chronic granulocytic leukaemia (CGL), from the clinical onset of the disease. In a previous study of different kinds of severe granulocytopenia, the AP positivity of circulating neutrophils appeared to indicate a kinetic parameter. Early release of mature, non-stored bone marrow granulocytes apparently furnished more AP+ neutrophils, whereas release of stored cells furnished more AP- cells. If we consider enzyme activity to indicate a kinetic parameter, its differential diagnostic usefulness would be less than generally supposed. One hundred and forty eight determinations in 74 CGL patients showed that low AP values are valid for CGL statistically, especially between the 2nd to 5th years of clinical disease, but normal or higher counts of circulating AP+ fraction of mature neutrophils could be found in one fourth of advanced cases (blastic metamorphosis excluded), and even more (17/37) in the earliest period of the CGL process. A similar tendency appears to be detectable in the absolute counts for circulating AP- cells.