Detection of IgA and IgC but not IgE antibody to respiratory syncytial virus in nasal washes and sera from infants with wheezing

Background and Obiective: The capacity of respiratory syncytial virus (RSV) to stimulate an IgE antibody response and enhance the development of atopy and asthma remains controversial. Nasal washes and sera from 40 infants (2 0 with wheezing, 9 with rhinitis, and 11 without respiratory tract symptoms ) were obtained to measure IgE. IgA, and IgG antibody to the immunodominant , F and G, virion proteins from RSV. Study design: Children (aged 6 weeks to 2 years) were enrolled in the emerg ency department during the mid-winter months and seen at follow-up when the y were asymptomatic. All nasal washes were tested for RSV antigen. Determin ations of antibody isotypes (IgE, IgA, and IgG) to RSV antigens were done i n nasal washes and sera by using an enzyme-linked immunosorbent assay. In a subset of nasal washes, IgE to RSV was also evaluated by using a monoclona l anti-FcE antibody-based assay. Results: Fifteen patients with wheezing, two with rhinitis, and one control subject tested positive for RSV antigen at enrollment. Thirteen patients w ith wheezing were <6 months old, and most (77%) were experiencing their fir st attack. Among the children with positive test results for RSV antigen, a n increase in both nasal wash and serum IgA antibody to RSV-F-a and G(a) wa s observed at the follow-up visit. However, there was no evidence for an Ig E antibody response to either antigen. Conclusion: Both IgA and IgG antibodies to the immunodominant RSV-F-a and G (a) antigens were readily detected in the nasal washes and sera from patien ts in this study. We were unable to demonstrate specific IgE antibody to th ese antigens and conclude that the production of IgE as a manifestation of a T(H)2 lymphocyte response to RSV is unlikely.