RSV caused bronchiolitis-clinical entity with characteristics of asthma

Acute bronchiolitis is a frequent disease in infants and difficult breathing and wheezing a condition similar to asthma manifest it. The most common causative agent of bronchiolitis is respiratory syncytial virus (RSV), which directly damages the respiratory system at also causes an immune reaction, which is assumed to be the key in pathogenesis of the disease. The aim of this research was to analyze the type of the immune reaction to RSV in connection with clinical findings. Subjects and methods: Out of the forty-four examined infants, RSV affected thirty-four of them and ten were RSV negative. Nine were healthy controls. RSV was proved in nasopharyngeal secret by the method of rapid virus detection by monoclonal antibodies in the immunofluorescent test and/or was isolate in cell cultures. Surface antigens CD20, CD21 and CD23 on B lymphocytes in peripheral blood was determined by flow cytometry with three color immunofluorescent method, and RSV-specific IgE and IgG4 antibodies in the serum of the same blood have been examined by immunoblot and immunodot methods. Anamnesis data and medical findings of affected infants have been obtained. Results: The percentage of CD23+ B cells was significantly higher in RSV positive infants then in RSV negative and in controls. There was no difference in antigens CD20 and CD21 markers among all groups of infants. Half of the infants affected by RSV-bronchiolitis had RSV-specific IgE and IgG4 antibodies. Nevertheless, their presence could not be connected with the clinical course of the disease, atopic predisposition or to clinical parameters. The duration of the wheezing in the infants with higher expression of CD23 antigen was longer. Conclusion: These findings corroborate the hypothesis that RSV could provoke a Th2-type response, and the appearance of RSV-specific IgE and IgG4 antibodies. However, they do not influence the clinical course of the disease but could be of prognostic value for later development of the bronchial asthma in children.