Introduction Children < 6 years and Elderly are more vulnerable to infections because the immune system is immature in children and the immunity falls with aging- > 60 years of age. It is the innate immune system which is also called as the inborn immune system. The Lung Innate System comprises of: 1. Airway epithelial barrier. 2. Alveolar macrophages 3. Dendritic cells 4. Neutrophils 5. Natural killer cells.
Innate immunity changes associated with infection: 1. Epithelium—Junctional barrier integrity, ciliated cell integrity and function, and Antimicrobial factor expression are all reduced and impaired. 2. Macrophage--- number, phagocytic capacity, and Antimicrobial factor expression are all reduced and impaired. 3. Dendritic cell--- Number, maturation, and capacity to activate T-cells are all reduced and impaired. 4. Neutrophial---Number, chemotaxis and antibacterial potential are all…
