Leukocytes are divided into two categories: granular and non-granular, and non-granular leukocytes include monocytes and lymphocytes. Granulocytes contain eosinophilic granules in their cytoplasm, or granulocytes, which can be divided into three types, namely neutrophils, eosinophils and basophils. Eosinophils have coarse eosinophilic granules that contain peroxidase and acid phosphatase within the granules.
Eosinophils are round in shape, with a diameter of 13-15 μm. The cytoplasm is filled with coarse, neat, uniform and tightly arranged brick-red or bright-red eosinophil granules with strong refractive properties. The nucleus is similar in shape to that of neutrophils, usually with 2-3 lobes, and is spectacle-shaped and dark purple. Eosinophils are easily fragmented and granules may be scattered around the cells. Today, we will share with you the clinical significance of various test results of eosinophils.
1.Physiological changes
Eosinophil decrease in peripheral blood can be caused by labor, cold, hunger, and mental stimulation. In normal people, eosinophils are lower during the day and higher at night. They fluctuate more in the morning and are more constant in the afternoon.
2.Eosinophilia
(1) Allergic diseases: bronchial asthma, allergic rhinitis, urticaria, drug and food allergy, angioneurotic edema, etc.
(2) Infections: such as parasites, Mycobacterium tuberculosis, Chlamydia, etc. Intestinal parasitic diseases can be as high as 90% or more, with complete deworming and elimination of infection and the blood picture gradually returned to normal.
(3) Some infectious diseases: In general, eosinophils in the blood are reduced in acute infectious diseases, but are increased in scarlet fever.
(4) Skin diseases: Eosinophils may be mildly or moderately increased in eczema, exfoliative dermatitis, aspergillosis, psoriasis, etc.
(5) Hematological diseases: eosinophilic leukemia, chronic granulocytic leukemia, malignant lymphoma, multiple myeloma, post-splenectomy, true erythrocytosis, etc.
(6) Connective tissue diseases: rheumatoid arthritis, Wegener’s granulomatosis, polyarteritis nodosa, etc.
(7) Tumors: lymphoma, various solid tumors or cystic fibrosis. Such as Hodgkin’s disease and certain epithelial lineage tumors such as lung cancer, are seen in eosinophilia, usually around 10%.
(8) Endocrine diseases: Addison’s disease, pituitary insufficiency, etc., often accompanied by eosinophilia.
(9) Immunodeficiency diseases: IgA deficiency, Wiskott-Aldrich syndrome, graft-versus-host disease, etc.
(10) Interstitial nephropathy.
(11) Idiopathic eosinophilia: when the patient has persistently high eosinophils and no other definite cause can be identified, it is called idiopathic eosinophilia syndrome.
3.Eosinophilia
It is seen in typhoid fever, paratyphoid fever, severe tissue injury after surgery, and after the application of adrenocorticotropic hormone or adrenal stimulating hormone.
4.Other applications of eosinophil count
(1) To observe the prognosis of acute infectious diseases
The adrenal cortex has the ability to promote the body’s resistance to infection, so when acute infection (such as typhoid fever), the secretion of adrenocorticotropic hormone increases, eosinophils do not decrease, and eosinophils gradually increase again during the recovery period. If the clinical symptoms are severe, and eosinophils do not decrease, it indicates adrenocortical failure; if eosinophils continue to decline, or even disappear completely, it indicates that the condition is severe punishment conversely, eosinophils reappear, or even increase temporarily, it is a sign of recovery.
(2) Observe the prognosis of patients with surgery and burns
Eosinophils decrease significantly 4 hours after surgery and gradually increase after 24 to 48 hours, and the rate of increase is basically consistent with the change of the disease. In patients with large burns, eosinophils disappear completely after a few hours and last longer. If eosinophils do not decrease or decrease very little after major surgery or large burns, this indicates a poor prognosis.
(3) Measurement of adrenocortical function.
ACTH can cause the adrenal cortex to produce adrenocorticotropic hormone, resulting in a decrease in eosinophils. After direct eosinophil count, ACTH 25mg was injected intramuscularly or intravenously to directly stimulate the adrenal cortex, or 0.1% epinephrine 0.5ml was injected to stimulate ACTH secretion from the anterior pituitary and indirectly stimulate the adrenal cortex. Eosinophil counts were then used 4 hours after the intramuscular injection or 8 hours after the start of the intravenous drip. The specific results of this test are interpreted and are not described here.