Sepsis, signals, and surgical sequelae (a hypothesis).

Cytokines, products of the bodies on cells, are the major signals that orchestrate the host's response to bacterial infection. Those signals generated following infection include interleukins 1, 2, and 6, interferon gamma, and tumor necrosis factor (or cachectin). Tumor necrosis factor is the only cytokine, to date, that has been shown to fulfill Koch's postulates and, thus, be casually related to host responses. Host responses to cytokines vary because of alterations in the genetic mechanism that controls cytokine production, because of an alteration in the responsiveness of the reticuloendothelial system at the time of signal induction and because of alterations in cell surface receptors. Only now are techniques evolving that can detect cytokine concentrations or production rates to relate these molecules to varying aspects of human disease. A major therapeutic goal in the future will be directed toward blocking the deleterious effects of cytokines while maintaining their protective or beneficial effects.