Eosinophils in rhinologic diseases

The eosinophil granulocyte, although likely first observed by Wharton Jones in 1846 in unstained preparations of peripheral blood, was so named by Paul Ehrlich in 1879 because of the intense staining of its granules with the acidic dye eosin [1]. Since that time the eosinophil has been the subject of extensive investigation. Its occurrence in such disparate conditions as parasitic infections, presumably for the benefit of the human host, and hypersensitivity diseases, perhaps to the detriment of the patient, although paradoxical, has become better understood as a consequence of newer information. Eosinophils are resident and non-pathologic in various organs such as gastrointestinal tract and mammary glands, and they may play roles in the tissue and immune homeostasis of these organs.