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  1. The eosinophils develop from the stem cells in bone marrow.
  2. Myeloid series cells get maturation under the influence of granulocytes colony-stimulating factor (G-CSF).


  1. Eosinophils are like neutrophils except the cytoplasm contains orange or red staining granules.
  2. The blood transient time for the eosinophils is longer than the neutrophils.
  3. There is a diurnal variation of eosinophils count.
    1. the lowest count will be in the morning, 10 AM to 12 AM and highest level at midnight (4 am).
  4. The eosinophils can act as phagocytic cells.
    1. Eosinophils are active in antigen-antibody complexes.
    2. Eosinophils are rich in histamine granules.
    3. Eosinophils take part in hypersensitivity reaction type 1.
  5. Eosinophils with the help of antibody IgE can produce histamine from the mast cells or the basophils.
  6. Eosinophils functions:
    1. It is detoxification.
    2. A special role in the allergic reaction.
    3. They are defensive against the parasitic infestation.
    4. Eosinophils remove the fibrin during the inflammation,
  7. If the eosinophils count is raised >1.5 X 10×9 /L for more than 6 months and associated with tissue damage. is diagnosed with the hypereosinophilic syndrome.



                                                                                                          Typical eosinophil with prominent eosinophilic granules.

Procedure to count Eosinophils:

1. The best method to count eosinophils is the automated analyzer.

2. Dunger's solution:

3. Phloxine stain: It consists of:

  1. Phloxine 0.1% solution to water 10 mL.
  2. Distilled water 40 mL.
  3. Propylene glycol  50 mL.
  4. Sodium carbonate 1%  1 mL.


  1. A sample of the blood is diluted in the WBC pipette as 1: 20 dilution with staining fluids.
  2. Mix well for 30 seconds.
  3. Now fill the chamber and count the colored eosinophils.
  4. Leave the chamber for at least 10 minutes to count the cells.


Source 2

Source 4

Eosinophilia, Increased Eosinophil count is seen in:

  1. when eosinophils are more than 5 % or > 500 cells/cmm.
  2. Allergic disorders.
    1. Bronchial asthma.
    2. Angioneurotic edema.
    3. Hay fever.
    4. Drug sensitivity.
  3. Skin diseases.
    1. Eczema
    2. Exfoliative dermatitis.
    3. Pemphigus.
  4. Parasitic infestations
    1. Especially those parasites which invade the tissue. e.g. Trichinosis, and  Echinococcus.
  5. Hematological disorders.
    1. Chronic myeloid leukemia.
    2. Polycythemia vera.
    3. Pernicious anemia.
    4. Hodgkin's lymphoma.
  6. Hypereosinophilic syndrome.
    1. Eosinophilic leukemia.
    2. Trichinosis invasion.
    3. Dermatitis herpetiformis.
    4. Idiopathic.
  7. Malignant tumors, especially with metastasis and necrosis.
  8. Miscellaneous.
    1. Loeffler’s syndrome.
    2. Tropical eosinophilia.
    3. Radiation.
    4. Rheumatoid arthritis.
    5. Tuberculosis.
    6. Sarcoidosis.
    7. Certain poison.

Eosinopenia, when < 50/cmm seen in the following conditions:

  1. Cushing’s syndrome.
  2. Due to some drugs like ACTH, epinephrine, thyroxine, and prostaglandin.
  3. In the shift to the left where there are immature cells.


Possible References Used

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