Infections, trauma, inflammatory processes, and some malignant diseases include a constellation of host responses collectively referred to as the "acute phase response". The response is associated with the charaacteristic metabolic changes in the liver protein synthesis, but on closer examination, changes also occur in several other systems and are responsible for various hematologic, endocrinologic, and immunologic dysfunctions. These changes are called "acute" because most are observed within hours or days following the onset of infection or injury, although some acute phase changes also indicate chronic disease. The full spectrum of the response includes dramatic increases in the synthesis of several unique hepatic proteins known as acute phase proteins or acute phase reactants.