A two-year course of specific immunotherapy or of continuous antihistamine treatment reverse eosinophilic inflammation in severe persistent allergic rhinitis.

Aim of the study was to evaluate the effect of a 2-year course of subcutaneous specific immunotherapy or continuous oral antihistamine treatment on the eosinophilic inflammation in nasal secretions of patients with severe persistent allergic rhinitis caused by house dust-mites. After informed consent, 31 rhinitis patients, sensitive to dust-mite antigens, were enrolled: 12 were randomly assigned to specific immunotherapy (group A), 11 to continuous oral antihistamine (cetirizine) treatment (group B), and 8 to an oral antihistamine (cetirizine) on demand (group C). Nasal scrapings were performed with a cotton-tipped swab and cells counted before and after 24 months of therapy. Intercellular adhesion molecule-1 and eosinophil cationic protein expression in cytological smears were assessed by immuno-histochemistry. All patients completed the study. The percentage of inflammatory cell types was comparable in the 3 groups at the beginning of the study. Eosinophils, identified as cells expressing eosinophil cationic protein, significantly decreased dropping to zero after 2 years of treatment in groups A and B, while no change was observed in group C. Expression of intercellular adhesion molecule-1 also decreased significantly in groups A and B, but not in group C. This decrease was associated with a significant reduction in epithelial shedding. In the 2-year period studied, specific subcutaneous immunotherapy and continuous oral antihistamine treatment were found to be effective in reducing eosinophilic infiltration and adhesion molecule expression in the nasal mucosa of patients with persistent allergic rhinitis. Furthermore, immunotherapy was more effective in controlling epithelial disruption while antihistamines appeared to be more active in controlling nasal inflammation. Both treatments induced a significant decrease in intercellular adhesion molecule-1 expression in epithelial cells and also a dramatic reduction of eosinophil cationic protein positive staining. These parameters can be considered useful means for controlling the state of persistent inflammation which is typical of persistent respiratory allergy. Nasal scraping was demonstrated to be a simple and safe procedure for monitoring some nasal inflammation parameters.