The Development of Respiratory Syncytial Virus-Specific IgE and the Release of Histamine in Nasopharyngeal Secretions after Infection

We studied the development of respiratory syncytial virus (RSV)-specific IgE and the release of histamine in nasopharyngeal secretions from 79 infants with various forms of respiratory illness due to RSV. RSV-IgE was measured by an enzyme-linked immunosorbent assay; specificity was confirmed by appropriate blocking experiments. Histamine content in the secretions was determined by fluorimetric methods. RSV-IgE was detectable in only one of 19 patients with RSV infection without wheezing, but was detectable in the majority of 60 patients with wheezing (P<0.01). Titers of RSV-IgE were significantly higher in patients with wheezing (P<0.05). Histamine was detectable in secretions of some patients with all forms of illness but was detected significantly more often (P = 0.05) and in higher concentrations in patients with wheezing. Peak titers of RSV-IgE and concentrations of histamine correlated significantly with the degree of hypoxia (P<0.001). Formation of RSV-specific IgE and release of histamine may adversely affect the outcome of RSV infection. (N Engl J Med. 1981; 305:841–6.) VIRAL infections are frequent causes of acute episodes of wheezing in childhood.^1,2 Previous studies have shown that respiratory syncytial virus (RSV) is the major cause of bronchiolitis in the first year of life^3,4 and of wheezing-associated respiratory illness in early childhood.^5,6 Little information is available concerning the mechanism by which infection with RSV and other viruses results in wheezing. An earlier study from our laboratory demonstrated the appearance of IgE antibody bound to the surface of RSV-infected epithelial cells in nasopharyngeal secretions obtained from patients with all forms of illness due to RSV infection.⁷ Cell-bound IgE was found to be.