Immunological, Viral, Environmental, and Individual Factors Modulating Lung Immune Response to Respiratory Syncytial Virus

Table 1

Factors involved in the lung response to respiratory syncytial virus infections.

Viral factors	Host and environmental factors	Immunological factors	Nonimmunological factors
(i) Subgroup [28]; (ii) Viral load and high infectivity [4]; (iii) Immune evasion mediated by G protein [28–32]; (iv) NS1 and NS2 proteins [14]	(i) Preexisting diseases [34, 35]; (ii) Young age [34, 35]; (iii) Exposure to tobacco smoke and traffic-derived pollution [34, 35]; (iv) Lack of breastfeeding [36]; (v) Daycare attendance [34, 35]; (vi) Siblings [34, 35]; (vii) Meteorological factors [37, 38]; (viii) Low levels of vitamin D [39]; (ix) Immunodeficiency [40]	(i) Innate immunity (neutrophils, eosinophils, and complement) [41–46]; (ii) Adaptive immunity (IgA, IgG, and T lymphocytes) [47–49]; (iii) Th1/Th2 balance [44]	(i) Anatomy of the airways in young infants [50]; (ii) Surfactant proteins [51]