Genetic variation and risk of sepsis.

Sepsis is the leading cause of death in non-coronary intensive care unit patients. Sepsis is caused by the immune response to infection and is manifest by pain, fever and edema as the result of the activation of coagulation and inflammatory responses. In severe cases, sepsis leads to organ dysfunction and failure. Sepsis affects more than 750,000 people each year in the US alone, with a mortality rate of over 35 percent making it one of the leading causes of death in developed countries. In addition many patients that die of other diseases have their hospital courses complicated by sepsis. Most patients with infection do not develop severe sepsis and septic shock and yet those that do have a significantly increased risk of death. Genetic and environmental variables may influence why one patient with infection gets sicker than the next. For example, people may be programmed to respond to infection in different ways; some with aggressive immune responses that may be able to wipe out infection before it manifests itself in physical symptoms, while others may have less aggressive immune systems that allow them to get sick more often. The discovery of various common genetic polymorphisms in genes that control the inflammatory response (e.g. tumor necrosis factor) has lent credence to this hypothesis. Yet discovery of the actual relationship between risks of infection / severe sepsis and individual genotypes will require larger, more rigorously designed studies.