Other Haemic Cells

Abstract

The quantitative neutrophil deficiency that is often present in HCL has been considered in Chap. 2. In addition, however, there are a number of features that suggest a qualitative neutrophil defect. The neutrophils consistently display an elevated level of alkaline phosphatase activity (Fig. 6.1), and the leukocyte alkaline phosphatase (LAP) score is almost always greater than 150 [171, 189, 202, 322]. Since elevated LAP scores are characteristic of myelofibrosis, the high score of HCL may be related to the marrow fibrosis of the disease; but this is not necessarily so, because high scores are also sometimes found in CLL [170]. Also, we have observed that in some patients the neutrophils fail to stain with either Sudan black or peroxidase methods: this abnormality may or may not be related to the neutrophil hypogranularity occasionally noted at the ultrastructural level.