Asthma aetiology: environmental stimuli may act on susceptible individuals, leading to altered immune response Environmental triggers Virus
Tobacco smoke
Genetically susceptible individuals
Allergens
Innate immune pathway
Adaptive immune pathway
Airway epithelial cells
Memory cell (B cell or T cell) Dendritic cell
Type 2 innate lymphoid cells
Natural killer T cell
Macrophage
Effector cell (eosinophil or mast cell)
1
Figure adapted from Holtzman MJ, et al. Nat Rev Immunol 2014;14:686–698.