STABLE SUDANOPHILIA OF HUMAN NEUTROPHIL LEUCOCYTES IN RELATION TO PEROXIDASE AND OXIDASE

It seems improbable that leucocyte oxidase is a fatty acid peroxide, as suggested by Sehrt, on these grounds: 1. Positive reactions for aldehyde and for ethylene groups are not obtained. Hence the presence of fatty acid peroxides in leucocytes seems unlikely. 2. Peroxidase has been isolated from leucocytes by Agner. Histochemical behavior on treatment with adverse reagents and with heat indicates similarity of benzidine peroxidase and of indophenol oxidase, but dissimilarity of these from the sudanophil substance in leucocytes. 3. Sudan dyes demonstrate or produce in neutrophil leucocytes deeply colored granules of quite variable size, and the size of the granules apparently increases with the duration of staining. 4. The demonstration of sudanophil granules in leucocytes is accomplished with difficulty. The colored granules are highly stable toward many Sudan dye solvents. Decolorization is difficult and recoloration is uncertain. 5. True fats and lipoids, after staining with Sudan dyes, are readily decolorized by appropriate dye solvents and are restainable in apparently undiminished amounts. 6. Some oxidants tend to impair sudanophilia of leucocytes. Potassium bichromate improves the preservation of sudanophil lipoids, as in the Ciaccio method, but destroys the sudanophilia of polymorphonuclear leucocytes. 7. Hydrogen peroxide apparently possesses an inconstant and irregular, though sometimes quite pronounced, accelerating effect on the production of Sudan stained granules in leucocytes. 8. The sudanophilia of leucocytes depends on an as yet unexplained chemical combination of the dyes with cytoplasmic constituents which are probably not in the form of preexisting granules, rather than on lipoid staining.