The relationship between inflammation and structural changes in the airways of the lower and upper respiratory tract : Studies in patients with asthma, Sjögren's syndrome, rhinitis and children with otitis media with effusion

Abstract: The pathophysiology of asthma, Sjögrens syndrome (SS), rhinitis, and otitis media with effusion (OME) in children has been extensively investigated in upper and lower respiratory tract, respectively, and shown to comprise structural changes in the airways and involvement of inflammatory cells. By comparing diseases that have bronchial hyperresponsivenses or mucosal inflammation as a common denominator, it may be possible to learn more about the mechanisms underlying inflammation in the upper and lower respiratory tract.With immunohistochemical techniques and a panel of monoclonal antibodies, inflammatory cells were identified and structural changes of the airway were quantitatively studied in the bronchial, nasal and middle ear mucosa and submucosa.The highest number of eosinophils and mast ceils in bronchial, nasal or middle ear biopsies was found in patients with atopic asthma (AA), perennial non-allergic rhinitis (PNAR) and children with OME. The number of the neutrophils was highest in SS, non-atopic asthma (NAA) and children with OME. The number of T lymphocytes in SS and AA was significantly higher than in NAA and healthy controls (HC). The degree of epithelial damage was higher in the AA group andin patients with perennial allergic rhinitis where the biopsy was taken within the pollen season (PARSEASON) group compared to the other patient groups. The tenascin- and Iaminin-positive layers in AA and SS were thicker than other groups. In AA, and PARSEASON a significant negative correlation was found between epithelial integrity and the count for eosinophils or neutrophils. The most pronounced epithelial damage was observed in patients with allergic rhinitis in areas characterized by an increased number of inflammatory cells. Eosinophils in asthmatic and PARSEASON patients and neutrophils in SS were found in the area of epithelial damage.This work has demonstrated a quantitatively different inflammatory profile in AA, NAA and SS, different profiles in perennial allergic and non-allergic rhinitis and a specific inflammatory profile in the middle ear of children with OME suggesting differences in the pathogenesis of respiratory tract diseases.