DYNAMICS OF NASAL EOSINOPHILS IN RESPONSE TO A NONNATURAL ALLERGEN CHALLENGE IN PATIENTS WITH ALLERGIC RHINITIS AND CONTROL SUBJECTS - A BIOPSY AND BRUSH STUDY

Background: Eosinophils are thought to play an important role in the s ymptomatology and pathophysiology of allergic rhinitis. Most quantitat ive studies on eosinophils in nasal mucosa have focused on the dynamic s of eosinophils in the acute and late phases of the allergic reaction by using different cell sampling techniques. Little is known about th e dynamics of eosinophils during a more prolonged period of allergen e xposure and the activation of eosinophils induced by, allergen challen ge. Objective: The aim of this study was to investigate the dynamics a nd activation of the he eosinophils in the nasal mucosa of patients wi th an isolated grass pollen allergy during an out-of-season 2-week all ergen exposure, mimicking the natural grass pollen season. Methods: Se venteen patients with isolated grass pollen allergy and four control s ubjects were challenged daily with the allergen during a 2-week period in the winter Nasal brush specimens were obtained before provocation and each day during the provocation period. Biopsy specimens were obta ined once before, six times during, and once after the provocation per iod. Preparations made of nasal brush and nasal biopsy specimens were stained with the monoclonal antibody BMK 13 and Giemsa stain as paneos inophil markers and with the monoclonal antibody EG2 to identify activ ated eosinophils. Results: We found significant increases in the total number of eosinophils and the number of activated eosinophils in the epithelium and lamina propria. These increases were most explicit in t he second week. BMK 13 was found to be a paneosinophil marker superior to Giemsa staining. Conclusion: Eosinophils are not only involved in the acute and late phases of the allergic reaction brit are probably e ven more involved in the chronic phase.