Peroxidase activity in circulating mast cells in blast crisis of chronic granulocytic leukemia. Comparative studies with basophils and cutaneous mast cells.

Although the hematopoietic origin of mast cells is very probable, the cell from which they originate is still a matter of speculation. The description of "transitional basophil/mast cells" in myeloproliferative disorders has suggested a common origin for basophils and mast cells. In a case of mast cell transformation of chronic granulocytic leukemia, the authors have studied the morphology and peroxidase activity by three classical technics, of circulating mast cells and transitional "basophil/mast cells." These results were compared with those of blood and bone marrow basophils and those of cutaneous mast cells. In both mast cells and "transitional basophil/mast cells," peroxidase activity was revealed in the nuclear envelope, endoplasmic reticulum, and granules. This activity was detected in unfixed cells and in tannic acid-aldehyde-fixed cells but not in 1.25% glutaraldehyde-fixed cells, where the staining appeared only in the granules. The comparison of this activity with that of normal basophils and mast cells suggests that the proliferating cells in this case possess at the same time the peroxidase activity of basophils and mast cells.