RELATIONSHIP BETWEEN VIRAL ANTIBODIES AND BRONCHIAL HYPERRESPONSIVENESS IN 495 UNSELECTED CHILDREN AND ADOLESCENTS

The purpose of this study was to investigate whether recent and previo us subclinical viral respiratory infection can explain the presence of increased bronchial responsiveness to histamine. We studied a randoml y selected population of 495 children and adolescents, aged 7-16 years , from Copenhagen. If the subjects had had symptoms of respiratory inf ection recently, the examination was postponed for at least 6 weeks. B ronchial hyperresponsiveness (BHR) to inhaled histamine was found in 7 9 (16%) of the subjects, of whom 28 had asthma. Forty-eight subjects ( 10%) had increased levels of serum IgM antibodies against either parai nfluenza, influenza, adenovirus, or respiratory syncytial virus (RSV), reflecting a recently acquired infection. No association between BHR and antibodies against respiratory viruses was found, as 7 (8.9%) of t he 79 subjects with BHR and 41 (9.9%) of the 416 subjects without BHR had viral antibodies. Furthermore, no association between degree of br onchial responsiveness and viral antibodies was found. Moreover, 251 i ndividuals (51%) had signs of earlier RSV infection, i.e. IgG antibodi es against RSV. No relationship was found between age of the subjects and the presence of antibodies against either respiratory viruses in g eneral or IgG-RSV. No relationship was found between the presence of a ntibodies against RSV and BHR; furthermore, evidence of earlier RSV in fection was unrelated to the level of lung function and degree of bron chial responsiveness. We conclude that increased bronchial responsiven ess in asymptomatic, unselected schoolchildren and adolescents is not likely to be caused by recent or previous viral respiratory infections .