ABSTRACT
The term inflammation predates modern understanding of the immune system but remains useful in medical practice to describe the events and clinical manifestations that occur when immune responses are concentrated and active at a particular site. Acute inflammation is initiated within minutes and typically lasts for several hours or a few days. The initiation of inflammation is often due to activation of complement, as well as pattern recognition receptors on tissue-resident innate immune cells such as macrophages, dendritic cells, mast cells, and natural killer cells. Acute inflammation involves the movement of white blood cells, particularly neutrophils, from the circulation into the site of tissue damage where they act to limit the extent of injury. The most important phagocytes in inflammation are the neutrophils and the macrophages. Macrophages can proliferate, but their numbers are also increased during inflammation by the exit from the circulation and maturation of bone marrow-derived monocytes.
