Role of Synergism between RV Infection and Atopy in the Pathophysiology of Intermittent Asthmatic Bronchitis in Adolescent Group in Mansoura

Abstract

Airway inflammation represents the corner stone in the pathogenesis of asthma which reflects the different aspects of the disease. Several studies had attributed several aspects in asthma pathogenesis to the interplay between Th1 and Th2 immune responses. Cytokines released by Th2 cells seem to play very important role in inducing allergic air way inflammation. To test the hypothesis that RV infection is responsible for asthma exacerbation in adolescent group and to test the relationship between RV infection and allergen sensitization. Seventy five adolescents were divided into 5 groups: control healthy group, group with controlled asthma without viral infection, viral infected group without asthma, asthmatic group with viral infection without atopy, and asthmatic group with viral infection with atopy. For all groups sputum samples were analyzed for eosinophile percentage, eosinophilic cationic protein concentration, IL 13 and IFy concentration using ELISA and RVRNA assay using real time PCR. Serum total IgE levels were also detected. Using the spirometer forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) % was measured for all groups. Asthmatic group with viral infection and atopy showed a heavy viral load in the sputum together with severe respiratory tract symptoms and asthma symptoms requiring hospitalization. This group also showed higher median serum total IgE levels as compared with other groups (P<0.05), significant higher IL13, eosinophil, and eosinophilic cationic protein concentration in the sputum (P<0.05) and significant lower IF-y concentration in the sputum (P<0.05) as compared with other groups but not significant lower IF-y concentration as compared with asthmatic group with viral infection without atopy. Asthmatic exacerbation in adolescent group with intermittent asthma is attributed to RV infection. RV and allergy act synergistically to worsen both viral respiratory tract symptoms and asthma symptoms. In this situation higher IL13 and total IgE levels together with lower IF-y level play an important role.