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Updated: Aug 25, 2026
An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
Acute and long-term effects of viral bronchiolitis in infancy
1Department of Child Health, King's College Hospital, London, United Kingdom.
Insights
Respiratory Syncytial Virus (RSV) causes most acute bronchiolitis in infants. Many children experience persistent wheezing and abnormal lung function for years after infection, suggesting long-term respiratory effects.
Area of Science:
- Pediatrics
- Infectious Diseases
- Pulmonology
Background:
- Acute bronchiolitis affects approximately 1% of infants, with Respiratory Syncytial Virus (RSV) being the primary causative agent in 85% of cases.
- Pathophysiological changes include inflammatory airway obstruction, epithelial necrosis, and mucous plugging, leading to dyspnea and hypoxia.
- Bronchodilator unresponsiveness suggests limited contribution of muscle spasm to airway narrowing.
Purpose of the Study:
- To investigate the long-term respiratory sequelae following acute bronchiolitis in infants.
- To explore potential factors influencing the development of persistent wheezing and bronchial hyperresponsiveness post-bronchiolitis.
- To examine the role of immune responses, such as IgE antibodies to RSV and leukotriene C4, in post-bronchiolitis wheezing.
Main Methods:
- Observational study analyzing clinical presentation and outcomes of infants hospitalized with acute bronchiolitis.
- Longitudinal follow-up of children to assess recurrent lower respiratory tract symptoms, lung function (e.g., FRC, dynamic compliance), and bronchial hyperresponsiveness.
- Analysis of respiratory secretions for IgE antibodies to RSV and leukotriene C4 in infants with and without post-bronchiolitis wheezing.
Main Results:
- Up to 75% of children experience recurrent lower respiratory tract symptoms after acute bronchiolitis, with many showing persistent hyperinflation and bronchial hyperresponsiveness.
- Abnormalities in small airway function are detectable up to 13 years post-infection, though most symptoms subside by school age.
- Elevated levels of IgE antibodies to RSV and leukotriene C4 were observed in infants with wheezing during and after bronchiolitis.
Conclusions:
- Acute bronchiolitis, primarily caused by RSV, can lead to significant and long-lasting respiratory issues, including persistent wheezing and impaired small airway function.
- While genetic predisposition to atopy does not increase bronchiolitis risk, viral-induced immune alterations may contribute to post-bronchiolitis wheezing.
- Further research is needed to understand the mechanisms of viral-induced immune modulation and its impact on long-term respiratory health.
Abstract:
About 1% of infants are admitted to hospital with acute bronchiolitis; 85% of cases are caused by infection with Respiratory Syncytial Virus (RSV). The pathophysiological changes during the acute illness are inflammatory obstruction in the small airways with submucosal cellular infiltration, epithelial necrosis and mucous plugging; FRC increases and dynamic compliance falls. Failure to respond to bronchodilator drugs suggests that muscle spasm contributes relatively little to the airway narrowing. Affected infants become increasingly dyspnoeic and hypoxic for 3-4 days then spontaneously improve. After an attack of acute bronchiolitis up to 75% of children have recurrent lower respiratory tract symptoms, many continue to have hyperinflated lungs and bronchial hyperresponsiveness. In the majority, symptoms of cough and wheezing have subsided by the time they start school, but abnormalities of small airway function are detectable at least 13 years later. Children with a genetic predisposition to atopy do not appear to have an increased risk of developing bronchiolitis. Evidence of genetic predisposition to bronchial hyperresponsiveness in those with persistent wheezing is controversial. There is little to suggest that neonatal lung damage or an adverse home environment are important factors in determining susceptibility to post-bronchiolitis wheezing. IgE antibodies to RSV, and leukotriene C4, are found more frequently in the respiratory secretions of infants who wheeze during and after bronchiolitis than in those who do not. The possibility of viral-induced alteration of the immune response at the time of infection needs further investigation.
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