REESTABLISHMENT OF HOMEOSTASIS AND THE ACUTE-PHASE PROTEINS

The stimulation of transcription of acute-phase protein (APP) genes in the liver is incorporated in the complex interchange of cytokines, gr owth factors and glucocorticoid hormones that are released during the systemic defence reaction in response to trauma, Through the broad spe ctrum of their activities, this heterogenous group of circulating prot eins assists the injured organism in restoring homeostasis by assuming a protective role, APPs accomplish this by inactivating vasoactive, p roteolytic and cytotoxic molecules liberated from damaged tissues and accumulating phagocytic cells, and by participating in a feedback cont rol mechanism that prevents an overload by the organisms' immune respo nse, APP synthesis represents a non-specific response of the liver, in somuch as different types of trauma elicit the production of the same proteins, However, data obtained from different laboratory models and clinical observations revealed a certain relationship between the seve rity and type of trauma and the magnitude of activation of APP gene ex pression, The observed variations of the overall pattern of APP synthe sis point to the existence of different interplays between humoral and cellular mediators capable of adjusting the production of individual proteins to suit different traumas, Hence, changes in the serum concen trations of some APPs have been shown to be useful in monitoring compl ications such as infection or sepsis after surgery or trauma, and pred icting the clinical course of malignant and other diseases, Of the APP s studied in humans, information obtained on CRP and SAA has in partic ular proved to be a useful indicator of the progression of different p athological states.