The Immune System Changes With Age

The innate immune system is comprised of a variety of cells and proteins that provide the first line of defense against infection and disease. With age, there is a progressive decline of components of the innate immune system, such as a decrease in the number of natural killer cells, phagocytes and complement proteins. Additionally, there is a decrease in the ability of these cells to detect, recognize, and respond to invading pathogens. There is also a decrease in the production of pro-inflammatory cytokines, which can lead to a decrease in the efficiency of the inflammatory response. Finally, the function of antigen-presenting cells, such as macrophages, is impaired with age, leading to a decrease in the ability to initiate the adaptive immune response.