What is an Eosinophil?

Normally mature white blood cells in the human body can be divided into five categories: neutrophils, eosinophils, basophils, lymphocytes and monocytes. Eosinophils are a component of white blood cells and, like other granulocytes, are derived from bone marrow hematopoietic stem cells. Eosinophils have the function of killing bacteria and parasites. They are also extremely important cells in the course of immune and allergic reactions. Eosinophils can release the contents of the particles, cause tissue damage, and promote inflammation. The number of eosinophils in the blood shows periodic diurnal fluctuations. The number of cells decreases in the early morning and increases in the number at midnight. This periodic change in cell numbers is related to the diurnal fluctuations in the amount of glucocorticoids released by the adrenal cortex. When the concentration of corticosteroids in the blood increases, the number of eosinophils decreases; while when the concentration of corticosteroids decreases, the number of eosinophils increases.

Basic Information

Chinese name

Eosinophil

Foreign name

eosinophilic granulocyte, eosinophil

Introduction to eosinophils

Eosinophils are a type of white blood cell. Leukocytes can be divided into two categories: granular and non-granular according to their morphological differences. Granular leukocytes (granulocytes) contain special stained granules. Three types of granular leukocytes, namely neutrophils, eosinophils, and basophils, can be distinguished by staining with Wright's dye; granulocytic cells include monocytes and lymph cell. Eosinophils have large eosinophilic granules containing peroxidase and acid phosphatase ^[1] .

Eosinophil morphology

Cells are 10-12 m in diameter, with nuclear lobes, or S-shaped or irregular, with lighter coloration. The cytoplasm contains eosinophilic particles, sized cells, unequal distribution, uneven distribution, stained orange-red, do not mask the nucleus. ^[2]

Eosinophils can migrate to sites with pathogens or allergic reactions. The cell can engulf the antigen-antibody complex, a variety of lysosomal enzymes released have a bactericidal effect, and the cationic protein has a strong killing effect on the parasite. At the site where the allergic reaction occurs, the histamine released by it can break down histamine, and the arylsulfatase ester can inactivate leukotriene, thereby inhibiting the allergic reaction.

Clinical significance of eosinophils

Increase

(1) Allergic diseases such as bronchial asthma, urticaria, drug allergy, and allergic purpura.

(2) Parasitic infections such as schistosomiasis, tsutsugamushi, and hookworm.

(3) Certain skin diseases such as eczema, exfoliative dermatitis, pemphigus, and psoriasis.

(4) Certain blood diseases such as chronic myelogenous leukemia, multiple myeloma, eosinophilic leukemia, lymphoma, eosinophilic granuloma, etc.

(5) Some malignant tumors and some epithelial tumors such as lung cancer.

(6) Certain infectious diseases such as scarlet fever.

(7) Other rheumatic diseases, hypopituitary dysfunction, hypoadrenal function, allergic interstitial nephritis, etc.

2. reduce

Patients with typhoid and paratyphoid fever; patients with long-term application of adrenal corticosteroids; stress conditions such as major surgery and burns.

Reference range of normal eosinophils

The percentage of eosinophils to the total number of white blood cells: 0.4-8.