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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.



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.


References in periodicals archive ?
Eosinophils are cells that actively participate in the defense against parasitic infections, in the regulation of hypersensitivity reactions, and in the destruction of cancer cells (Kay, 1985; Dvorak et al.
2% CTAB in 20 mmol/L Tris-HCL, 1% BSA, was optimal for extraction of the proteins within the eosinophils and neutrophils.
Esophageal biopsies before and after the 6 weeks of treatment showed that intraepithelial eosinophil counts decreased significantly, from a median of 41 per high-power field to less than 1 per high-power field (Gastroenterology 1995;109:1503-12).
Patients were randomized to receive treatment based on the British Thoracic Society (BTS) guidelines or treatment based on eosinophil counts.
Steve Yancey, Vice President and Medicine Development Lead for mepolizumab, GSK said: We believe the data published today in the New England Journal of Medicine demonstrate the benefits of a personalised medicine approach in the treatment of COPD with mepolizumab, using blood eosinophils as a biomarker.
Higher T2S scores correlated with increased eosinophils in airway walls, percentage of blood eosinophils, bronchodilator reversibility, and improvement in hyperinflation after corticosteroid treatment.
To study the presence of eosinophils in nasal smear of patients with allergic rhinitis.
Finally, patients with allergic conditions were excluded because such patients may have higher eosinophil counts.
B16F1 cells, co-cultured with eosinophils treated with VA/ML, showed reduced cell proliferation compared to cells co-cultured with untreated eosinophils.
A patient with mild peripheral blood eosinophilia might also have noteworthy organ involvement by eosinophils.
Although the role of eosinophils in allergic airway inflammation isn't completely understood, these little critters are recruited to the lungs during the immune response and result in antigen presentation and cytokine production.