Skoner DP, Gentile DA, Angelini B, Doyle WJ. Ann Allergy Asthma Immunol. 2006;96:834–839
PURPOSE OF THE STUDY. To determine if a viral upper respiratory infection affects allergy skin-test responsiveness.
STUDY POPULATION. Sixteen adults experimentally exposed to respiratory syncytial virus (RSV).
METHODS. Subjects without concurrent upper or lower airway disease were cloistered and inoculated with 106 plaque-forming units of RSV type B. Daily physical examination and symptom scores were recorded. Nasal lavages were performed and stored at −70°C for RSV-antigen assay and culture. Blood samples were obtained for immunoglobulin E (IgE) measurement on days 0, 2, 4, 6, 8, 10, and 21. Skin-prick testing was performed for 17 locally relevant aeroallergens and controls on days 0, 3, 6, and 21.
RESULTS. Eight patients had ≥1 positive skin-test result at baseline and were considered atopic. Eleven (5 atopic, 6 nonatopic) had evidence of postinoculation RSV infection. Atopic patients had a higher IgE level at baseline as compared with nonatopic subjects (123 ± 80 vs 45 ± 36 IU/mL; P < .01). There was no change in total IgE level in those in the nonatopic group, but the atopic subjects had a nonsignificant increase in IgE level on days 8 and 10 (146 ± 112 IU/mL). Of the 8 nonatopic patients, only 3 had negative skin-test results to all antigens on all 3 postinoculation test days. The mean number of positive wheal responses to allergens for all patients was 1.7 ± 2.3, 4.4 ± 3.8, 3.6 ± 3.5, and 3.9 ± 3.6 at baseline and days 3, 6, and 21, respectively (P < .01 versus baseline for all pairings). For patients with positive skin-test results at baseline, mean wheal and flare area provoked by those allergens increased after RSV exposure. The increased number of positive responses to skin testing was noted for both seasonal and perennial aeroallergens.
CONCLUSIONS. The results may have some implication in explaining complications of RSV infection such as otitis media, asthma exacerbation, and subsequent development of asthma.
REVIEWER COMMENTS. There has long been a chicken-and-egg question when it comes to RSV infection in childhood and subsequent development of asthma. That is, does RSV predispose to later recurrent wheezing illnesses, or does the predisposition to wheeze lead to worse outcomes with RSV infection? Are children with an atopic predisposition more likely to have a severe RSV infection, or are those with severe infection more likely to develop atopy? This small study did not answer the question, but it provides a hint that RSV infection itself might affect immunologic responsiveness to aeroallergens, at least in the short-term. The study results cannot be extrapolated to make any long-term conclusions. Furthermore, the study was undertaken in healthy adults. It would be unethical to intentionally infect infants and toddlers with RSV at an age when they might be most susceptible to the risks of environmental influences on the development of atopy and to the risks of the infection itself.
- Copyright © 2007 by the American Academy of Pediatrics