Morphologic, cytochemical, and ultrastructural features of gray eosinophils in nine cats

Abstract

In the dog, the term "gray eosinophil" reflects the presence of variably sized, unstained granules resembling clear vacuoles. 2 Ultrastructural characterization of canine gray eosinophils shows a decrease, not only in the overall secondary granule size but also in the dense matrix and outer rim width, resembling changes observed in people with eosinophil peroxidase deficiency. 3 Functional abnormalities have not yet been found, and their distinctive cytologic appearance is thought to be due to a difference in granule staining properties, which appears more prominent with aqueous Romanowsky stains such as Diff-Quik. 1,2 Accurate recognition of these cells is important in peripheral blood film examinations