Eosinophilic granulocytes are involved in different inflammatory processes, including atopic, parasitic and rheumatic diseases. The most prominent feature of the eosinophils are their large secondary granules, each containing four basic proteins, the best known protein is the eosinophil cationic protein (ECP). Elevated ECP levels are found in atopic diseases such as allergic asthma and allergic rhinitis but also occasionally in other diseases such as bacterial sinusitis.
The ECP level in humans correlates with the disease activity or the severity of diseases of the atopic disor-ders. For this reason the parameter provides externalization and therapy monitoring of bronchial asthma or atopic dermatitis.