The Use of Acute Phase Proteins as Biomarkers of Diseases in Cattle and Swine

The acute phase response is a nonspecific and complex reaction of an organism that occurs shortly after any tissue injury. The origin of this response can be attributable to infectious, traumatic, immunologic, neoplastic, or other causes, in order to restore homeostasis, reduce tissue damage, and to remove the cause of disturbances [1]. The acute phase response is characterized by a number of different systemic effects, a range of metabolic activities and alterations in a wide variety of biochemical processes. One of the most important metabolic changes is the strongly increased (or decreased) production and secretion of some plasma proteins from the liver, the acute phase proteins [2]. The acute phase response is a very fast response, developing with increased concentrations of acute phase proteins within a few hours, which remain elevated as long as the inflammatory stimulus persists [3]. For this reason, they represent the ideal tool for the early identification of inflammation or injury, and for monitoring the outcome of disease processes. Unfortunately, acute phase proteins are poorly specific, since they increase in the presence of inflammation independent of the agent respon‐ sible, but the increase in their concentrations indicates that „something“ is happening in the body, and should lead clinician to investigate the site, type and severity of the inflammation (complete clinico-pathological approach), to identify the pathogen responsible (specific diagnostic methods), and to follow-up the treatment.