Meldola Blue for the cytochemical demonstration of leukocyte dehydrogenases

The new electron carrier Meldola Blue was employed in the cytochemical demonstration of succinate, lactate, and glucose-6-phosphate dehydrogenases in leukocytes. A significant increase in dehydrogenase activity, with better localization and less diffusion of the reaction product, was observed when compared to enzyme reactivity carried out without Meldola Blue. Meldola Blue can facilitate the demonstration of both bound and soluble leukocyte dehydrogenases. Current methods which could yield better visualization of leukocyte dehydrogenases, particularly succinate, lactate, and glucose-6-phosphate dehydrogenases in neutrophils, suggest excellent use can be made of Meldola Blue in the clinical laboratory. Reliable histochemical determination of these enzymes can aid in differentiating younger from older neutrophils. In addition, glucose-6-phosphate dehydrogenase might be used in conjunction with the nitroblue tetrazolium (NBT) test in separating persons with bacterial infections from those with nonbacterial illness. Furthermore, histochemical visualization of this enzyme may also prove beneficial in identifying glucose-6-phosphate dehydrogenase-deficient individuals.