Abstract

The eosinophils of a patient with eosinophilic leukaemia were studied with 13 different cytochemical methods using light and electron microscopy. Apart from the 'left shift' of the eosinophils in bone marrow and peripheral blood, the following morphological changes were noted: uncoordinated maturation of the nucleus and cytoplasm, changes in size of the specific granules, and hypogranulation to such an extent that some of the cells bore only very few granules. The cytochemical studies showed a strongly positive periodic acid Schiff reaction in the eosinophils, caused by a high content of glycogen, and a relatively strong positive acid-phosphatase reaction. These cells were also tested for aryl sulphatase and coenzyme Q. Electron microscopy confirmed the presence of a high-content glycogen and a strong acid phosphatase response in the cells. Peroxidase reaction, detected in electron microscopy as well, enabled us to trace the maturation of the eosinophil cell line.