Hematology: eosinophil

Overview

• Eosinophils are generally involved in inflammatory processes in the body, which may either be helpful in cleansing the body of something or harmful and damage tissues. Primarily involved in killing parasites or regulating the intensity of hypersensitivity reactions.
• Attracted into tissue primarily by histamine (mast cells and basophils) and lymphokine (lymphocytes) to neutralize histamine, serotonin and bradykinin resulting in an anti-inflammatory effect. Peroxidase, present in specific eosinophilic granules, exert some anti-inflammatory effect at sites of antigen-antibody interaction, even when histamine is not involved.
• Other functions are fibrin degradation (profibrinolysin produced by developing eosinophils in the bone marrow), phagocytosis and detoxification.
• Kinetics: reservoir of 300-400 eosinophils in bone marrow (75% mature) for every one in circulating blood.
• Lifespan in circulation ?8-15 days.
• Blood transit time is +/- 30 minutes.

Result data

Normal (reference) values

• <1.5 x 10/L.

Abnormal values

• Eosinophilia, in the presence of stress (neutrophilia and lymphopenia), may be an unfavorable sign since it can denote advancing body protein decomposition.
  Eosinophilia (>750/ml)
  
• Diseases of tissues containing a large number of mast cells: skin - allergies, lung - allergic asthma    . gastrointestinal tract - eosinophilic gastroenteritis    , female genital tract - during estrus (the uterus contains the most number of mast cells during proestrus and the least during estrus).
• Certain diseases are more likely when eosinophilia is present but the converse is not true, eg food hypersensitivity    is more likely in the presence of eosinophilia but eosinophilia eosinophilia is not always present when there is a food hypersensitivity.
• Parasitism : filariasis (heartworm) , hookworm , lungworm, fleas    .
• Allergies : allergic bronchitis or sinusitis, hay fever, gastrointestinal or food, skin - urticarial lesions and vesicles, anaphylactic reaction, angioneurotic edema.
• Eosinophilic myositis .
• Catabolism : chronic suppurative disease, malignancies.
• Hemopoietic disorders : eosinophilic leukemia, post-splenectomy (after 1 month).
• Neoplasia , especially those involving ovary, bone    , serous membranes.
• Post-radiation therapy (after 2-3 weeks).
  Eosinopenia
  
• Systemic stress.
• Glucocorticoid administration.