The Cytokine Network in Trauma and Sepsis I: TNF and IL-8

During infection and sepsis the genes for many cytokines are expressed and some of the proteins are also released both locally and into plasma. Teleologically, such cytokine response must be beneficial to the host. However, from a certain threshold level of activation there might be an overactivation and imbalance of the cytokine sys tem, which then tends to be harmful to the host. It is difficult to make a strict classification of cyto kines, but nevertheless some of them can be seen as proinflammatory (e.g., tumor necrosis factor, TNF) and some as anti-inflammatory molecules (e.g., in-terleukin 4, transforming growth factor-β?). In considering the role of cytokines in sepsis, it should be emphasized that some of these molecules occur in sequence in vivo, with possible reciprocal amplification or inhibition cascade.