Eosinophils in the blood - the norm and causes of deviation from the norm

Synonyms: EO

Eosinophils consist of a bilobed nucleus and three types of eosinophil granules (lipid bodies, eosinophils, small and primary). They contain protein structures with the help of which foreign cells are neutralized. Eosinophils are quite large cells: their diameter reaches 20 microns.

Eosinophils got their name due to the fact that when stained according to Romanovsky, they are easily stained with eosin (an acidic dye), while other types of dyes have no effect on them. Eosin itself was invented in 1873 by the German scientist G. Caro and, due to its bright pink color, was named after the ancient Greek goddess of the dawn Eos (in the German version the name sounds like “eosin”).

What are eosinophils?

The content of the article

Eosinophils are a type of granular leukocytes or granulocytes. Their cells include a bipartite nucleus and three types of eosinophilic granules - lipid bodies. They contain protein structures that neutralize foreign bodies and substances. Eosinophils are large cells with a diameter of up to 20 microns.

Eosinophils got their name because when stained according to Romanovsky, they are easily stained with eosin dye. This dye was invented in 1873 by the German scientist G. Caro and, because of its bright pink color, was named after the ancient Greek goddess of the dawn Eos - in the German version “eosin”.

Eosinophils are formed in the red bone marrow within 3-4 days. After this, they enter the bloodstream, accumulating in the mucous membranes of the intestines, respiratory tract and capillaries. There they live and function for 10-14 days. In peripheral blood the concentration of eosinophils is insignificant. There are about 200 times more of them in the bone marrow and other tissues.

Indications for analysis

A complete blood test with a count of eosinophils is prescribed for most people who visit the clinic.

The range of indications is very wide, but in modern clinical practice the initial eosinophil count is most often used:

• as a biomarker for assessing the effectiveness of drugs prescribed to patients with bronchial asthma;
• upon confirmation of a preliminary diagnosis;
• checking the effectiveness of the prescribed therapeutic course;
• assessing a person’s health status during medical examinations or medical examinations;
• in the postoperative period;
• if the development of infectious, oncological and autoimmune diseases is suspected.

Which blood test shows the level of eosinophils?

The exact number of eosinophils is indicated in the results of a blood test with a leukocyte formula. Blood is taken from a vein or finger for analysis. The study is carried out under a microscope using various reagents and dyes. During this analysis, the number of all types of leukocytes per unit volume of blood is calculated, as well as the percentage of each type of leukocyte. A leukogram (leukocyte formula) allows you to see the increase and decrease in the number of one or another type of leukocyte.

Norms of eosinophils in the blood

In women, in the first days of menstruation, the level of eosinophils is slightly higher than normal, and after ovulation their number is slightly lower than normal.

An increased level of eosinophils in the blood is called eosinophilia.

Consequences of deviation from the norm

A change in the normal level of eosinophils in the blood is not a criterion by which one can get an idea of ​​possible pathological changes in the body. Simply put, the level of eosinophils in the blood itself means little - you need to pay attention to the disease that caused its change. Therefore, the consequences can be very diverse - from completely insignificant (as in the case of physical activity) to deadly (for example, in the case of oncology).

Eosinophilia itself, in rare cases, can lead to damage to tissues in which the greatest accumulation of eosinophils is observed. The mechanism of such damage has not been fully studied to date, but it has been established that eosinophils exhibit the most severe damaging effect in conditions such as eosinophilic fibroplastic endocarditis and idiopathic hypereosinophilic syndrome. The nature of the damage directly depends on the duration of eosinophilia and the severity of eosinophilic tissue infiltration.

Stages of eosinophilia

Blood test for eosinophils

To determine the level of eosinophils, a general blood test is used, which is familiar to all of us since childhood. Eosinophils by themselves do not give an accurate idea of ​​the nature of pathological changes in the body, however, in combination with other values ​​of the leukocyte formula, they allow a specialist to judge the nature of the pathology. In the analysis form, eosinophils are designated as EO. Their content is indicated as a percentage of the total number of leukocytes. A formula is also used to calculate the absolute number of eosinophils in peripheral blood and it looks like this: number of leukocytes * 10 to the 9th power. For a general analysis, blood is most often taken from a finger prick, but venous blood is also suitable.

Figure 1. Causes of eosinophilia (increased number of eosinophils in the blood). Image: kavusta/Depositphotos

Causes of increased levels of eosinophils in the blood

An increase in eosinophils or eosinophilia is observed in the following diseases and conditions:

• diseases and conditions accompanied by allergic processes in the body - bloating, bronchial asthma, urticaria, Quincke's edema, serum sickness, drug sickness, etc.;
• parasitic diseases – ascariasis, giardiasis, toxocariasis, trichinosis, opisthorchiasis, echinococcosis, malaria, etc.;
• concomitant tissue diseases and systemic vasculitis - rheumatoid arthritis, mesothelial periarteritis, scleroderma, systemic lupus erythematosus, etc.;
• dermatological diseases - dermatitis, eczema, skin crocus, pemphigus, etc.;
• some infectious diseases - tuberculosis, scarlet fever, syphilis;
• blood diseases accompanied by the spread of one or more hematopoietic bacteria - chronic myeloid leukemia, erythremia, lymphogranulomatosis;
• taking sulfonamides, antibiotics and adrenocorticotropic hormones.

Long-term (more than six months) high eosinophilia of unknown etiology is called hypereosinophilic syndrome. The level of eosinophils in the blood exceeds 15%. This pathology is very dangerous, it causes damage to internal organs - heart, kidneys, bone marrow, lungs, etc.

If the content of monocytes and eosinophils in the blood is increased, this may indicate an infectious process in the body, a blood disease, or an early stage of cancer.

Sometimes the number of monocytes increases after recovery from various diseases.

If eosinophils are elevated

It is obvious that in children and adolescents the eosinophil count may increase to 6–7%, but this then goes away with age. If eosinophils are elevated in an adult, this indicates a pathology that requires diagnosis and treatment.

Eosinophils increase in children and adults in many diseases and conditions:

• infection with worms, especially lamblia, roundworms, strongyloides, echinococci, hookworms, schistosomes, toxocara, opisthorchiasis, pulmonary flukes and trichinella;
• asthma;
• allergy;
• hay fever;
• skin manifestations of allergies;
• malaria;
• recovery from infectious diseases;
• after taking antibiotics;
• serum sickness;
• hay fever;
• epidermolysis bullosa;
• atopic dermatitis;
• pemphigus;
• Dühring's dermatitis;
• nephroblastoma (Wilms tumor);
• carcinoma;
• cirrhosis of the liver;
• rheumatoid arthritis;
• pernicious (megaloblastic or B12-deficiency) anemia;
• all types of leukemia;
• lymphogranulomatosis (Hodgkin's lymphoma);
• polycythemia vera;
• fasciitis;
• Sezary syndrome;
• Wegener's granulomatosis;
• periarteritis nodosa;
• Churg-Strauss syndrome;
• sarcoidosis;
• pneumonia;
• Addison's disease;
• Loeffler's syndrome and Loeffler's endocarditis;
• condition after radiotherapy and irradiation;
• scarlet fever;
• Congenital heart defect;
• condition after removal of the spleen;
• GVHD after organ transplantation;
• tuberculosis of the lymph nodes;
• chorea;
• tumor metastases (especially to the bones and lungs);
• systemic lupus erythematosus.

An increase in these blood cells is called eosinophilia. The attending physician finds out the cause of this condition and looks for a way to eliminate it.

How to reduce the number of eosinophils in the blood?

First of all, it is important to eliminate the cause of eosinophilia, that is, the disease that caused a change in the leukocyte formula.

Possible treatment options:

• antiallergic therapy - taking antihistamines: chloropyramine, cetirizine, levocetirizine, desloratadine and loratadine, etc.;
• antibacterial therapy - taking antibiotics: amoxicillin, ceftriaxone, azithromycin, erythromycin, etc.;
• anti-inflammatory therapy - taking drugs for inflammatory processes, for example glucocorticosteroids - prednisolone;
• chemotherapy – to eliminate malignant tumors;
• hormone therapy;
• anthelmintic therapy - taking albendazole, levamisole, bephenium hydroxynaphthoate, piperazine, tetrachlorethylene, mebendazole. The choice of medication depends on the type of parasite and the stage of infestation.

Additionally, the following measures can be taken:

1. Normalize your lifestyle. It is important to avoid frequent drinking of alcohol and give up cigarettes.
2. Avoid chronic intoxication. In people working in hazardous industries or living in environmentally unfavorable regions, the number of eosinophils in the blood increases as a result of constant chemical intoxication.
3. Stick to a healthy diet. You should not overuse spicy, smoked, canned and fatty foods. To increase the level of eosinophils, you should limit the amount of meat, poultry and fish in your diet, and consume mainly their low-fat varieties. The menu should include yogurt, cheeses, vegetables, fruits, beans, bran and whole grain bread.

How to increase the number of eosinophils in the blood?

A decrease in the level of eosinophils in the blood is a sign of weakened immunity. As in the case of eosinophilia, the primary pathology should be identified and eliminated, as well as lifestyle adjustments:

• minimize bad habits;
• ensure an adequate level of physical activity;
• take care of the normal daily routine;
• consume more foods containing vitamins B12, C, D - meat, fish, cottage cheese, rose hips, currants, garlic, or use pharmacy multivitamins.
• It is advisable to exclude foods with a high allergenic potential: milk, soy, wheat, eggs, seafood, peanuts.

Changes in the level of eosinophils in the blood can be caused by both physiological reasons - physical activity, stress, overeating, and various diseases. Sometimes the same condition, for example, an allergy or an infectious process, can cause both a decrease and an increase in the number of eosinophils in the blood and other biological fluids.

Etiology of eosinophilia

The reasons for the increase in eosinophil concentration are varied:

• allergic reactions;
• infection with worms and parasites;
• pulmonary pathologies - Loeffler's syndrome, eosinophilic pneumonia, allergic reaction to pulmonary forms of aspergillosis, pulmonary infiltrates with eosinophilia, Churg-Strauss syndrome (one of the systemic vasculitis), sarcoidosis;
• blood pathologies - pernicious anemia, polycythemia vera, non-Hodgkin's lymphoma, acute or chronic myeloid leukemia, as well as eosinophilic leukemia, Sezary syndrome;
• endocrinopathies;
• malignant tumors - carcinomatosis, adenocarcinoma of the gastrointestinal tract, urinary and reproductive systems, lungs and some other cancers;
• some benign tumors;
• primary immunodeficiencies - hyper-IgE syndrome (or Jobe syndrome), T-lymphopathies, Wiskott-Aldrich syndrome, neutrophil chemotaxis defect;
• tuberculosis;
• some dermatological pathologies;
• gastrointestinal pathologies;
• mixed conditions - magnesium deficiency, idiopathic eosinophilia, recovery period after infectious diseases, AIDS, chorea, congenital heart disease, scarlet fever, hypoxia, radiation, reaction to transplantation, condition after peritoneal dialysis, etc.;
• drug-induced eosinophilia caused by taking certain medications.