What Are the Causes of Eosinophilia?

Eosinophils are a component of white blood cells. Like other granulocytes, hematopoietic stem cells are derived from bone marrow. The granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin 3 (IL-3), interleukin 5 ( IL-5) proliferate, differentiate, and mature into eosinophils under the action of cytokines. 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. Eosinophils in normal human peripheral blood account for 0.5% to 5% of white blood cells, with an absolute value of 0.05 to 0.5 × 10 ⁹ / L. If eosinophils are higher than 0.5 × 10 ⁹ / L, it is called eosinophilia.

Basic Information

English name

eosinophilia

Visiting department

Internal medicine

Common causes

1. Increased reactivity; 2. Increased secondary; 3. Increased clonal eosinophils; 4. Increased idiopathic

Common symptoms

Corresponding symptoms based on affected tissues and organs

According to the affected tissues and organs, eosinophilia is often described under different disease names. Mainly: eosinophilic pneumonia (pulmonic eosinophil infiltration, PIE), eosinophilic gastroenteritis, eosinophilic granulomatous vasculitis (Churg-Strauss syndrome), eosinophilic intracardiac Meningitis, eosinophilic myalgia syndrome, etc.

Causes of eosinophilia

Eosinophilia can be divided into four categories based on the cause:

Increased reactivity

(1) Allergic diseases such as: bronchial asthma, allergic rhinitis, drug allergy, etc .;

(2) Infection such as: parasites, tubercle bacilli, chlamydia, etc .;

(3) skin diseases such as: psoriasis, eczema, exfoliative dermatitis, etc.

2. Secondary increase

Accompanying certain diseases, such as: connective tissue disease (rheumatoid arthritis, Wegener granulomatosis, nodular polyarteritis, etc.), tumors (lymphoma, various solid tumors or cystic fibrosis), endocrine diseases (Addison disease, pituitary dysfunction, etc.), immunodeficiency disease (IgA deficiency, Wiskott-Aldrich syndrome, graft versus host disease, etc.), interstitial nephropathy.

3. Clonal eosinophilia

In this case, eosinophilia is a manifestation of malignant disease. Such as: chronic eosinophilic leukemia, chronic myeloid leukemia, acute myeloid leukemia (AML-M4EO), and myeloproliferative disorders. In recent years, it has been found that PDGFRA, PDGFRB, and FGFR gene abnormalities can cause severe persistent eosinophilia. These diseases are a special type of chronic bone marrow proliferative tumors, and targeted treatment drugs are very good for patients with these diseases. Curative effect.

4. Idiopathic increase

When the patient's eosinophilia continues to increase without being able to find another identified cause, it is called idiopathic eosinophilic syndrome (IHES).

Clinical manifestations of eosinophilia

According to the different tissues and organs involved, corresponding symptoms appear.

Eosinophilia test

1. Accurately determine the absolute value of eosinophils in peripheral blood;

2. Look for parasites in peripheral blood, bone marrow and stool;

3. bone marrow puncture examination;

4. Liver and kidney function, related autoantibodies, serum VitB ₁₂ ;

5. Chest X-ray examination, echocardiography, chest and abdominal CT should be performed if possible.

6. Decide whether a tissue biopsy is needed based on the specific organ involvement.

7. When clonal eosinophilia is suspected, cytogenetics and molecular biology tests should be performed.

8. Flow cytometry to determine if there is an abnormal lymphocyte phenotype.

Diagnosis of eosinophilia

It can be diagnosed based on laboratory test values, but it is important to find the cause of eosinophilia.

Diagnostic criteria for idiopathic eosinophilia syndrome:

1. Peripheral blood eosinophils> 1.5 × 10 ⁹ / L, which lasted for more than 6 months, or died within 6 months after clinical symptoms appeared. The clinical symptoms are non-specific, and can manifest as fever, rash, fatigue, cough, shortness of breath, muscle aches, or diarrhea. Physical examination can reveal rashes, lymphadenopathy, hepatosplenomegaly, rales in the lungs, abdominal tenderness or nervous system abnormalities.

2. No cause of eosinophilia was found.

3. There are symptoms or signs of organ involvement, such as shadows in the lungs, abnormal heart ultrasound, and so on.

Eosinophilia treatment

Reactive or secondary

The treatment for the primary disease is the most important.

2.IHES treatment

The first treatment is glucocorticoids. For hormone resistance, you need to increase or switch to cytotoxic drugs, such as: hydroxyurea, cyclophosphamide, and maliline. Pay attention to adverse reactions such as bone marrow suppression. A-interferon can be used after hormone therapy failure. Other treatment methods, such as: IL-5 monoclonal antibody, allogeneic hematopoietic stem cell transplantation, cyclosporine A and so on.

3. Other

For patients with chronic myeloproliferative tumors with PDGFRA gene abnormalities, imatinib has an effective rate close to 100%, and the dosage is usually lower than that of slow granules, but long-term maintenance treatment is required.