chapter  5
16 Pages

Respiratory Viruses: Do They Protect From or Induce


Asthma is a chronic, inflammatory disease of the airways in which both genetic and environmental factors contribute to disease development and expression. Sensitization to aeroallergens with the subsequent formation of allergen-specific IgE antibodies in individuals with a genetic predisposition to atopy is believed to be central to the pathogenesis of the disease. This abnormal immune response to inhaled allergens leads to chronic airway inflammation with a characteristic eosinophilic infiltrate. There is also increasing evidence that T lymphocytes expressing a predominantly type 2 pattern of cytokine production orchestrate this inflammatory response. Despite the central role of allergic mechanisms in asthma pathogenesis, it is recognized that other nonallergic factors influence the asthmatic phenotype, including exercise, airborne pollutants, psychological factors, and respiratory tract infections.