Variations in histamine, IgE and interferon concentrations in nasal secretions and seraof children with asthma associated with viral or mycoplasma infection

Histamine and virus‐specific IgE appear to play some role in the pathogenesis of wheezing which occurs during viral infection. Respiratory viruses can enhance IgE‐mediated histamine release in vitro partly by inducing interleron (IFN). To investigate the role of histamine, IgE, and IFN in the pathogenesis of asthma associated with infection, we prospectively studied hospitalized infants and children (8 months to 17 years of age) with acute episodes of asthma. Patients were enrolled and acute samples were collected within 2 days of admission; convalescent samples were obtained 1 to 4 weeks later. Patients were separated into virus/mycoplasma‐assoeiated and noninfectious asthma groups by comprehensive virologic and serologic techniques. One third of acute asthma episodes proved to be virus/mycoplasma‐associated. In both asthma groups, nasal wash histamine values were significantly higher during acute attack, compared to convalescence. However, during acute attack, there was a trend for more detectable histamine and in higher concentrations from patients with infectious asthma, compared to the noninfectious group. Histamine was correlated with nasal wash and serum IgE during acute episodes of only infectious asthma. Nasal wash or serum IFN levels did not differ between the 2 patient groups. However, high IFN titers were detected in sera of all 3 patients with asthma associated with RSV infection, although RSV is known to be a poor IFN inducer. Our findings suggest an agreement with the hypothesis that histamine and IgE may play a role in attacks of asthma which arc associated with viral or mycoplasma infection. Further studies are required to confirm our obsmution and to evaluate the role of other inflammatory mediators in the mechanism of infectious asthma.