Measuring eosinophilic cationic protein (ECP) helps evaluate patients suspected to have a condition associated with eosinophilia or hypereosinophilia, evaluating patients with elevated peripheral blood eosinophil counts.
Eosinophilic cationic protein (ECP) is a small basic protein found predominantly in eosinophil granules, a type of white blood cell involved in allergic responses and parasitic infections.
Structure and Function: ECP is a 15-kDa protein with a net positive charge due to its high arginine and lysine residue content. It possesses ribonuclease activity, which allows it to degrade RNA in target cells. ECP is released from eosinophils upon activation, either by allergens or cytokines, and contributes to the immune response against pathogens, particularly parasites.
Role in Allergic Diseases: ECP is implicated in the pathogenesis of various allergic conditions such as asthma, allergic rhinitis, and atopic dermatitis. In allergic diseases, eosinophils infiltrate tissues in response to allergen exposure, releasing ECP and other inflammatory mediators, leading to tissue damage and inflammation.
Cytotoxic Effects: ECP exhibits cytotoxic effects against bacteria, parasites, and specific cells. Its mechanism of action involves disrupting cell membranes and inducing cell death, making it an essential component of the immune response against pathogens.
Diagnostic and Prognostic Marker
- ECP levels in blood, sputum, and other bodily fluids are often elevated in conditions associated with eosinophilic inflammation.
- Measurement of ECP levels can aid in diagnosing and monitoring allergic diseases and other eosinophil-related disorders.
- High ECP levels may indicate disease activity and severity, while decreasing levels may correlate with treatment response.
More Information
ECP (Eosinophil Cationic Protein) levels tend to rise in diseases where eosinophil-mediated tissue inflammation is a factor. They can also increase in people diagnosed with eosinophilic esophagitis. Measuring ECP levels has been a reliable method to evaluate eosinophil-mediated allergic inflammation, asthma, and rhinitis. ECP levels can increase during seasonal and perennial rhinitis, which may indicate current allergen exposure. Studies have demonstrated that ECP levels correlate with the symptoms and total clinical score in atopic dermatitis.
Eosinophilic inflammation is a common feature of asthma, though it is not a definitive diagnosis. Elevated levels of ECP (eosinophil cationic protein) are believed to indicate the degree of asthma-related bronchial eosinophilic inflammation. Increased ECP levels coincide with the onset of symptoms and can precede bronchial hyperreactivity. ECP has been used to evaluate asthma severity and manage anti-inflammatory therapy. It should be noted, however, that ECP is more closely correlated with symptom scores than with lung function parameters, particularly in children with mild to moderate asthma.
ECP levels can be increased in several gastrointestinal disorders, including eosinophil intestinal diseases (esophagitis, gastroenteritis, and colitis), food allergy, and intestinal parasitic infections.
Eosinophil cationic protein (levels can increase in non-IgE-mediated conditions, such as nonallergic asthma with aspirin intolerance, respiratory infections, sinonasal polyposis, and idiopathic hypereosinophilia (HES) syndrome. ECP can also serve as a disease activity marker in Churg-Strauss syndrome (CSS), also known as allergic granulomatosis or allergic angiitis. CSS is a disorder characterized by inflammation of blood vessels, which can lead to the narrowing of blood vessels and reduced blood flow to essential organs and tissues, causing permanent damage in severe cases.
