Comparison of rhinovirus antibody titers in children with asthma exacerbations and species-specific rhinovirus infection

Background Asthma exacerbations are associated with human rhinovirus (HRV) infections, and more severe exacerbations are associated with HRV-C. We have previously shown that the HRV-C–specific antibody response is low in healthy adult sera and that most of the antibody to HRV-C is cross-reactive with HRV-A. Objectives To compare the antibody response to each HRV species in asthmatic and nonasthmatic children in whom the type of HRV infection was known. Methods Total and specific IgG1 binding to HRV viral capsid protein antigens of HRV-A, -B, and -C were tested in the plasma from nonasthmatic children (n = 47) and children presenting to the emergency department with asthma exacerbations (n = 96). HRV, found in most of the children at the time of their exacerbation (72%), was analyzed using molecular typing. Results Asthmatic children had higher antibody responses to HRV. The titers specific to HRV-A, and to a lesser extent HRV-B, were higher than in nonasthmatic controls. The species-specific responses to HRV-C were markedly lower than titers to HRV-A and HRV-B in both asthmatic and nonasthmatic children (P < .001). The titers both at presentation and after convalescence were not associated with the HRV genotype detected during the exacerbation. Conclusions The higher total anti-HRV antibody titers of asthmatic children and their higher anti–HRV-A and -B titers show their development of a heightened antiviral immune response. The low species-specific HRV-C titers found in all groups, even when the virus was found, point to a different and possibly less efficacious immune response to this species.