Eosinophil cationic protein
Eosinophil cationic protein (ECP) is one of the proteins that make up the granules of eosinophils. Eosinophils are immune blood cells that perform the following functions: protection of the body from parasitic infection, inactivation and prevention of the long-term promotion of biologically active substances involved in allergic reactions. When eosinophils are activated by antibodies and cytokines, their degranulation occurs, that is, the release into the bloodstream of the contents of granules, ECP in particular.
The role of eosinophil cationic protein in the body:
1. Prevention of degranulation of basophils and mast cells. These cells are directly involved in allergic reactions and related disease such as: bronchial asthma, atopic dermatitis, allergic rhinitis, conjunctivitis, otitis media;
2. Toxic effect on the nervous system of helminths (e.g., ascarids);
3. Inhibition of reproduction (proliferation) of cancer cells;
4. Antiviral and bactericidal promotion.
However, ECP is not harmless to the body, its excess causes side effects of the protein such as itching of the skin, death of bronchial epithelium, increased secretion of bronchial mucus, toxic effect on the myocardium. Manifestations depend on the localization of the allergic reaction.
The diagnostic value of determining the level of ECP is to assess the severity of eosinophilic inflammation. The level of ECP correlates with the severity of allergic diseases. Dynamic observation of the amount of ECP in the blood in patients with bronchial asthma allows predicting the onset of an attack, assessing the severity of the course, monitoring the effectiveness of treatment. ECP is considered a marker of allergic disease exacerbation, as the concentration of ECP increases sharply when an allergen enters the body.
A special role is given to the diagnosis of allergic diseases in children, since the age of the child does not always allow obtaining the necessary clinical data by interview. In addition, many complaints of children are subjective.
Another application of ECP is the diagnosis of DRESS-syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms). DRESS syndrome is caused by drug intolerance and is manifested by a skin rash, internal organ damage, and an increase in blood eosinophils (eosinophilia). Most often the syndrome occurs when taking NSAID, co-trimoxazole, penicillin-type drugs, phenytoin, phenobarbital, sulfanilurea drugs.