Like the neutrophil, the eosinophil is a bone marrow derived, blood-borne polymorphonuclear leucocyte, but unlike the neutrophil its cytoplasm stains pink on haemotoxylin/eosin staining, and electron microscopy (see fig: 1.21) shows the large angular granules that characterize this cell. Eosinophil appear to be selectively attached to tissues as the result of specific chemotaxins (e.g. IL-5 and the other chemokines RANTES and eotaxin that are separated by macrophages and T lymphocytes). Most of the granule contents are common to the neutrophil, although some agents, e.g. eosinophil peroxidase (EPO) and major basic protein (MBP), are specific for the eosinophil. Eosinophils have probably evolved to aid human host defense against parasites such as schistosomes and worms, but they are also implicated in allergic disease such as asthma.
From the book of:
DAVIDSON’S
Principles and Practice of Medicine
Eighteenth Edition
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