Related Experiment Videos
Immunological mechanisms of severe respiratory syncytial virus bronchiolitis
1Wilhelmina Children's Hospital, University Medical Center, POB 85090, 3508 AB Utrecht, The Netherlands.
Insights
Immature immune systems in infants, particularly premature neonates, are key factors in severe respiratory syncytial virus (RSV) bronchiolitis. This immaturity, affecting both cellular and humoral immunity, contributes to severe illness and the need for mechanical ventilation.
Area of Science:
- Pediatrics
- Immunology
- Infectious Diseases
Background:
- Respiratory syncytial virus (RSV) bronchiolitis is a common cause of respiratory insufficiency in infants, often requiring intensive care.
- While pre-existing cardiac or pulmonary conditions are known risk factors, many severe cases occur in previously healthy infants.
Purpose of the Study:
- This review evaluates factors contributing to severe RSV bronchiolitis.
- It specifically examines the role of immune system immaturity in infants.
Main Methods:
- The study is a review of existing literature on severe RSV bronchiolitis.
- It analyzes documented clinical risk factors and immunological findings.
Main Results:
- Infants possess maturation-related deficiencies in cellular immunity.
- Low virus-specific antibody titers and decreased cellular immunity are associated with severe RSV bronchiolitis.
- Higher viral loads are observed in infants with more severe illness.
Conclusions:
- Immaturity of the infant immune system, including both cellular and humoral components, is a significant factor in the pathogenesis of severe RSV bronchiolitis.
- This immune immaturity contributes to the need for mechanical ventilation in affected infants.
Abstract:
Respiratory syncytial virus (RSV) bronchiolitis resulting in respiratory insufficiency is frequently encountered during the winter season in paediatric intensive care units. This review evaluates potential determinants described in severe RSV bronchiolitis with special attention to the role of immaturity of immune responses during infancy. Pre-existent cardiac or pulmonary compromises have been documented as clinical risk factors for severe RSV bronchiolitis. In addition to this group of infants with pre-morbidity, a large proportion of mechanically ventilated RSV bronchiolitis patients are previously healthy full-term infants or premature neonates without predisposing risk factors. In general, infants at this early age have maturation-related deficient cellular immunity. Several studies show an association between decreased cellular immunity and severe RSV bronchiolitis, indeed suggesting that a maturation-related defect of the cellular immune system facilitates severe RSV. In addition, low virus-specific antibody titres prior to RSV bronchiolitis have been shown to be a risk factor for severe RSV bronchiolitis. A low level of cellular and humoral immunity would explain that higher viral titres are found in infants with most severe illness. In conclusion, immaturity of the physiological functions in healthy pre-term infants and neonates, in particular the immune system, appears to be an important factor in the pathogenesis of RSV bronchiolitis resulting in mechanical ventilation.