Eosinophil granulocyte
Eosinophil granulocytes - also called eosinophils or " Eos " for short - belong to the class of leukocytes . They make up about 1–5% of the leukocytes in the differential blood count and are involved in the cellular immune defense. They get their name from the dye eosin , with which they can be colored. Eos (ancient Greek) means dawn.
Inside, eosinophilic granulocytes contain vesicles , also called granules , which contain basic proteins , e.g. B. contain the major basic protein , lysosomal hydrolytic enzymes and peroxidase . The contents of the granules can be released into the environment by exocytosis . The triggers for this include antibodies of the IgE class. Furthermore, they are capable of chemotaxis , i. That is, they can move amoeboid in the direction of an attractant. In addition to the toxic effects of their granules, eosinophils also have the ability to phagocytose .
Eosinophils play an important role in defense against parasites . As soon as the surface of the parasite is covered with IgE, eosinophils bind to it. This acts as a stimulus for the toxic content of the granules to be released onto the surface of the parasite. At the same time, in addition to damaging the parasite, the exocytosed proteins serve as attractants for other eosinophils, so that the defense can be strengthened.
Eosinophils can also play a harmful role for the organism itself. In bronchial asthma, for example, the lung epithelium is damaged by the components of the eosinophils. For COPD , different treatments are possible depending on the amount of eosinophils in the blood. Rare diseases caused by eosinophils are eosinophilic fasciitis and hypereosinophilic syndrome, and eosinophilic esophagitis .
Physiologically, the eosinophils are increased in the lymphocytic-eosinophilic healing phase. The number is also higher in the case of allergies , so that so-called eosinophilia is an important indicator of the presence of an allergy. A decrease in the number of eosinophils is called eosinopenia . In cats and dogs, especially in connection with allergies, eosinophils can migrate into the skin ( eosinophilic granuloma complex in cats, eosinophilic facial furunculosis in dogs).
literature
- Jesse C. Nussbaum, Steven J. Van Dyken, et al. a .: Type 2 innate lymphoid cells control eosinophil homeostasis. In: Nature. 502, 2013, pp. 245–248, doi: 10.1038 / nature12526 .
See also
swell
- Roche Lexicon Medicine Keyword: granulocytes
- Gerd Herold : Internal Medicine . Cologne 2007, p. 52 f .
Web links
Individual evidence
- ↑ H. Magnussen, B. Disse, R. Rodriguez-Roisin, A. Kirsten, H. Watz, K. Tetzlaff, L. Towse, H. Finnigan, R. Dahl, M. Decramer, P. Chanez, EF Wouters, PM Calverley: Withdrawal of inhaled glucocorticoids and exacerbations of COPD. In: The New England Journal of Medicine . Volume 371, Number 14, October 2014, pp. 1285-1294, doi: 10.1056 / NEJMoa1407154 , PMID 25196117 .