Eosinophils are a feature of upper and lower airway pathology in non-atopic asthma, irrespective of the presence of rhinitis

Background Asthma and rhinitis often co-exist and there are data to suggest that they may be two ends of the same disease spectrum. Immunohistochemica l studies have shown that eosinophilia in the airways is a feature of rhini tic patients without asthma. Objective The aim of our study was to examine whether cellular infiltration exists in the nasal mucosa of asthmatics even in the absence of symptoms a nd signs of rhinitis. Methods Nasal mucosa biopsies were taken from 27 non-atopic subjects and co mprised nine asthmatic rhinitic patients (AR), eight asthmatic non-rhinitic patients (ANR) and 10 healthy control subjects (N). Bronchial mucosa biops ies were also taken simultaneously from some of the patients (n = 10) to de termine whether there was an association between cellular infiltration in t he nose and the lungs. The alkaline phosphatase-anti-alkaline phosphatase ( APAAP) method was used on 6 mu m thick cryostat sections using monoclonal a ntibodies against T cells (CD4, CD8), eosinophils (EG2) and mast cells (mas t cell tryptase). Slides were counted blind and results expressed as cells per field. Results The results showed that eosinophil counts were higher in both asthm a groups compared with control nasal biopsies (median values AR 8.3, ANR 9. 2, N 2.1 cells per field, P < 0.01). Furthermore, there was a significant c orrelation between eosinophil cell counts in the nose and the airways (r = 0.851 P < 0.001). No differences in eosinophil numbers were detected betwee n the two groups of asthmatics. Also, no differences were noted for any oth er cell type (i.e. CD4, CD8, tryptase) among the three study groups. Conclusions These results show that eosinophil infiltration was present in the nasal mucosa of asthmatic patients even in the absence of rhinitis, and add further support to the hypothesis that asthma and rhinitis are clinica l expressions of the same disease entity.