Published Online April 25, 2014
Exacerbations of asthma in children are frequently associated with human rhinovirus (HRV) infections, and HRV-induced wheeze in infancy is a predictor of the development of asthma. The newly recognized HRV-C species reportedly accounts for the majority of attacks in children presenting with asthma and is associated with more severe attacks than HRV-A and HRV-B. Despite the similarity of their names, there are considerable differences in their biology and the proteins they produce.
In a study recently published in The Journal of Allergy and Clinical Immunology, Iwasaki and colleagues highlight important differences between the immune responses to HRV-A and HRV-C and the difference in responses of non-asthmatic children with those prone to asthma exacerbation. Combining the measurement of antibody binding to the main virus coat protein (VP1) with the molecular typing of species of HRV found at the time of a virus-associated asthma exacerbation revealed children with asthma exacerbations had higher total antibody binding to HRV antigens compared to non-asthmatic controls showing a heightened aspect of their immune response to HRV.
However, when species-specificity of the responses was dissected out with antigens from different species, the high responses were found for HRV-A, and to a lesser extent HRV-B. In contrast, the species-specific responses to HRV-C were markedly lower than titers to HRV-A and HRV-B not just for asthmatic but also non-asthmatic children. For asthmatics, the HRV-C antibody binding was low both at the time the emergency department presentation and after convalescence, and was low irrespective of whether HRV-C or another virus was found during the exacerbation. The high total and anti-HRV-A antibodies were also independent of the virus found at the time of recruitment.
The higher total anti-HRV antibody titers of asthmatic children and their higher anti-HRV-A and -B specific titers show they develop a heightened anti-HRV immune response compared to non-asthmatics. The low species-specific HRV-C titers found in all groups, even when virus was found, show a different and possibly less efficacious immune response to the species associated with frequent and severe exacerbation.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.