Activated and non-activated eosinophils in patients with chronic rhinosinusitis

Nasal polyps develop out of an oedematous swelling of the mucous membrane, which is probably a localized mediator-dependent reaction of the mucous membrane in the lamina propria. Among other things, eosinophil cationic protein (ECP) is released from activated eosinophils. In previous studies, ECP was considered as measuring the degree of allergic dermatological illnesses and therapy was given accordingly. A group of 54 patients with massive polyposis requiring functional endoscopic sinus surgery was examined. After surgery they were treated with local and systemic cortisone. Polypous tissue samples were collected and counted for the number and ratio of activated and non-activated eosinophils, and the serum titre of ECP was measured simultaneously using a fluoroimmunoassay (test kit, Kabi Pharmacia, Sweden). The aim of the study was to evaluate the activity of the disease and to gain hints for a specific therapy. The presence of these eosinophils was demonstrated by immunohistochemical methods, using EG1 antibodies against non-activated and EG2 antibodies against activated (i.e. secreted form of ECP) eosinophils. Depending on the duration of treatment with systemic and local corticosteroids, there was a considerable decrease in activated eosinophils and the level of serum ECP. Consequently, cortisone can be applied in the treatment of eosinophilic nasal polyps. As the number of activated eosinophils in the tissue is an indicator for the activity of the chronic inflammation it can be deduced from our study that local and/or systemic cortisone application successfully stops the growth of eosinophilic nasal polyps. The number and ratio of activated and non-activated eosinophils seem to be reliable indicators for the activity of chronic polyposis.