Antibody responses to rhinovirus and echovirus antigens in children with asthma exacerbations

Background: Exacerbations of asthma in children are frequently associated with rhinovirus (RV) infections and rhinovirus-induced wheeze in infancy is a predictor of the development of asthma. In contrast, there is evidence for an association of a reduced risk of childhood atopy and infection with echoviruses, a gut-trophic virus that, like rhinovirus, belongs to the Enterovirus genus.Aims: To assess the absolute and specific antibody titres to VP1 antigens of the lung-trophic rhinovirus and the gut-trophic echovirus in asthmatic and non-asthmatic children.Methods: Recombinant polypeptides representing the VP1 capsid antigens of all three RV species and echovirus 30 were produced. Their ability to bind IgG1 antibodies from the plasma of asthmatic (n=45) and non-asthmatic (n=29) children were quantitated by immunoassays that incorporated immunoabsorptions to remove cross-reactivity.Results: The IgG1 antibody titres and prevalence of antibody binding to echovirus 30 were significantly lower for asthmatic children compared to controls ( P u003c 0.05), and inversely correlated with total IgE levels for the whole study population ( r = -0.262; P u003c 0.05). Asthmatic children had higher total antibody binding to RV antigens compared to non-asthmatic controls and when species-specificity of the responses were dissected out, the high responses in asthmatics remained for the highly prevalent RV-A species.Conclusions: The associations of lower antibody titres of asthmatic children to echovirus and a heightened response to rhinovirus suggest a dichotomy where respiratory enterovirus infection/immunity increases the probability of developing asthma and enteric infections lower the risk.