On the nature of Romanowsky dyes and the Romanowsky‐Giemsa effect

Abstract

Summary  This paper reviews the nature of Romanowsky staining and the relationship between Romanowsky dyes and the Romanowsky‐Giemsa effect (RGE). On blood and bone marrow smears the RGE is characterized by a purple colouration of nuclei and neutrophil granules. The nuclear purple contrasts strongly with the blue cytoplasmic staining of cells rich in RNA. Requirement for the occurrence of RGE are: 1 A cationic dye: The best dye is azure B and, though azure A gives the nuclear purple colour, the cytoplasmic blue is inferior. No other cationic dye such as methylene blue is suitable. 2 An anionic dye: Most commonly eosin Y is used, but it can be replaced by the erythrosins. Full halogenation of the fluorescein (four atoms of bromine or iodine) is not necessary. Phloxine and rose bengal are unsuitable. 3 An appropriate substrate: These are proteins with acidic side groups or proteins bound to a polyanion. For interaction with the dyes substrates must provide a suitable three‐dimensional network which is why the RGE is not obtained in solutions. A tentative theory of RGE is advanced and briefly discussed. Copyright © 1979, Wiley Blackwell. All rights reserved