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A granular leukocyte having cytoplasmic granules that stain with acid dyes and a nucleus with two lobes connected by a thin thread of chromatin.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a cell of vertebrates, including man, whose cytoplasm contains rounded granular structures that are stained by acid dyes, in particular by eosin. The eosinophils of the blood originate and mature in the bone marrow. They comprise 3–4 percent of leukocytes in the peripheral blood of a healthy human being. This level is subject to a daily rhythm and is regulated by the system which includes the pituitary body and the adrenal cortex.

In allergic reactions, eosinophils release the inhibitor histamine, which belongs to the prostaglandins E1 and E2. They also serve as phagocytes.

An increase in the percentage of eosinophils in the peripheral blood or an increase in their absolute number is called eosinophilia. As a rule, this condition is reactive in character, regardless of the degree of its severity. The possibility of developing eosinophilic leukemia is still a matter of dispute. Eosinophilia is accompanied by various reactions and diseases, predominantly allergic, including those related to the breaking down of the body’s resistance by parasites or medicinal and food allergens. Aggregations of eosinophils observed in the tissues, as, for example, in the mucosa of the bronchi (and sputum) in bronchial asthma, are called tissue eosinophilia. Eosinophilic infiltrates, large aggregations of eosinophils in the tissues, are occasionally observed in various organs, predominantly the lungs. They may run their course as short-term reactions or result in such severe illnesses as pneumonia, myocarditis, vasculitis, and meningoencephalitis. A number of other diseases are also accompanied by a high eosinophilia. In some cases it is impossible to establish the nature of the disease that is accompanied by a high eosinophilia. The condition may be observed even in people who are otherwise healthy.

Hürtle cells, one of the types of cells of the anterior lobe of the pituitary body, are also called eosinophils.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
When a person has symptoms and an elevated number of eosinophils in their tissues, organs, and/or bloodstream, without a known cause, he/she may have an eosinophil-associated disease.
"We found that the higher the number of eosinophils in the tumor, the less severe the disease, which represents a clear correlation," said Munitz.
Eosinophil cationic protein can be measured in plasma, saliva, sputum, nasal bronchoalveolar lavage fluid, digestive tract mucosa, feces, and urine (5, 6).
The diagnostic role of peripheral blood eosinophil count and eosinophil-derived proteins (eosinophil-derived neurotoxin and major basic protein) has been documented in previous studies.
Our group found that the Bcl-2 inhibitors ABT-737 and ABT-199 can induce apoptosis in immune cells, including eosinophils, neutrophils, Th2 cells, and Th17 cells.
Statistical analysis: Data obtained from the area of granulomas, and the counting of lymphocytes, macrophages, and eosinophils in different dpi, were analysed with Kruskal-Wallis test, and to compare differences between days post-infection a test of Dunn was used.
Despite the acknowledged contribution of eosinophils to the disease pathogenesis, available data on cytokines closely related to the development and activity of peripheral eosinophils in IBD patients are either scattered or nonexistent.
In our previous study [3], apart from the number of eosinophils in the biopsies, we looked at four histologic features retrospectively: eosinophilic microabscesses, basal epithelial hyperplasia, papillomatosis, and spongiosis within the two groups.
Some authors suggest a value as low as at 6 eosinophils per HPF [15], some 15 to 20 [2, 16], some 30 [17], and some 50 [18].
Differential cell counts were carried out in cytocentrifuged preparations stained with May-Grunwald Giemsa dye, under oil immersion objective to determine the percentage of mononuclear cells, eosinophils, and neutrophils.
Eosinophils are a type of white blood cell that are a normal part of the body's immune system.