To clarify the ultrastructural and functional charcteristics of basophils in CML, the author observed the morphological changes of cells by scanning electron microscopy (SEM), and examined the density and redistribution of IgE receptors using an immuno-SEM technique. Histamine content and release of histamine from basophils upon addition of anti-IgE were also measured. Mature basophils, corresponding to types I and II in the basophilogram, had a spherical shape, while immature cells, corresponding to types III and IV, were pearshaped. Type I, II, III and IV basophils differed in the number of microvilli, more mature basophils having more microvilli than immature basophils. The mean number of bound immunolatex particles, which indicate IgE receptors, was 19.3±14.0/basophil in healthy subjects, 42.4±30.9 in bronchial asthmatic, and 3.7±6.6 in CML patients. The number of IgE receptors in the blastic phase of CML was much lower than in the chronic phase of CML. The histamine content of basophils was 0.5±0.3 pg/cell in the blastic phase of CML compared with 1.4±0.4 pg/cell in the chronic phase of CML, 1.3±0.4 pg/cell in healthy subjects and 1.4±0.4 pg/cell in bronchial asthmatic. These data indicate that immature basophils of CML have some morphological and functional defects.
chronic myelocytic leukemia