Inflammation is a protective response which results from tissue injury or destruction.
Physically, it is characterized by pain, heat, redness, swelling and loss of function. Histologically, it is characterized by events which include dilatation of arterioles, leakage in capillaries and venules, exudation of plasma, and migration of leukocytes into the inflammatory focus. If the inflammatory response is prolonged or chronic, it ceases to provide a protective response and instead causes extreme discomfort as well as extensive tissue damage. The clinical incidence of inflammatory disease is high. The role of PAF in the inflammatory response is particularly important.