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[Causative relations between infections and allergies in obstructive respiratory tract diseases in childhood]
D Reinhardt1, M Griese, K Morgenroth
1Zentrum für Kinderheilkunde der Universität Düsseldorf.
Insights
Respiratory viruses like RSV cause obstructive bronchitis in infants, potentially leading to asthma. While viral infections damage airways, these changes are reversible, and predicting later asthma development remains challenging.
Area of Science:
- Pediatric Respiratory Medicine
- Virology
- Immunology
Context:
- Obstructive bronchitis is common in infants and young children.
- Viral infections are frequent triggers for respiratory symptoms in this age group.
- The link between early respiratory infections and later asthma development is an area of ongoing research.
Purpose:
- To explore the viral causes of obstructive bronchitis in different age groups.
- To elucidate the mechanisms by which viral infections induce airway hyperresponsiveness and allergy.
- To investigate the role of specific viruses, such as respiratory syncytial virus (RSV), in pediatric obstructive airway disease.
Summary:
- Respiratory-syncytial (RS) and parainfluenza viruses are primary causes of obstructive bronchitis in infants, with adenoviruses also implicated.
- In school-aged children, rhinoviruses and Mycoplasma pneumoniae become more significant.
- Viral infections can trigger or worsen asthma attacks, often through epithelial damage, mast cell activation, and altered immune responses, including IgE production.
- Pathological changes in bronchial epithelium during infection are reversible, but the long-term prediction of asthma development after such episodes is difficult, especially in children with a family history of atopy.
Impact:
- Provides insights into the pathogenesis of viral-induced obstructive airway disease in children.
- Highlights the role of specific viruses in triggering allergic sensitization and airway hyperresponsiveness.
- Informs clinical understanding of the relationship between acute respiratory infections and the potential for chronic respiratory conditions like asthma.
Abstract:
Obstructive bronchitis of young babies and infants is most often caused by respiratory-syncytial (RS)- and parainfluenza viruses, to a certain extent by adenoviruses. In the school age-group rhinoviruses and to a smaller extent mycoplasma pneumoniae gain further importance. All the viruses may cause or deteriorate asthmatic attacks, as well as during common cold or on the basis of documented allergies. Proposed mechanisms of viral-infection-induced obstructive airway disease are distinct lesions of bronchial-epithelium, followed by enhanced allergen-resorption and sensitization of submucosal mast cells, establishing an allergy. Following epithelial discontinuation airway irritant receptors which are raised in sensitivity by viral toxins are exposed and stimulated. Via vago-vagal reflexes this leads to bronchoconstriction. Furthermore, in the development of bronchial hyperresponsiveness there may be participation of virus-induced blockage of adrenoceptors, basophilic and mast-cell release of mediators as well as induction of specific IgE antibodies against RS- and/or Para-influenza-viruses. Viral airway infections are supposed to influence the immunological response of T-lymphocytes and probably macrophages selectively, e.g. to regulate IgE-antibody production. Especially in children with an atopic family history the RS-viruses cause obstructive airway disease. During acute respiratory-virus infections using electron microscopy marked pathological changes of bronchial-epithelium can be demonstrated causing disturbance or even stopage of mucus-transport. These changes are fully reversible within weeks after airway infection. Although there is no doubt about a causative relation between respiratory-tract infection and allergy, hardly any prediction for development of asthma bronchiale in later life, after having suffered from virus-induced obstructive airway disease early in life, can be made.(ABSTRACT TRUNCATED AT 250 WORDS)