USA Surgery Today

In the early twentieth century, Ehrlich and Metchnikoff were awarded Nobel prizes for recognizing the two basic components of the immune system: the humoral and cellular elements. In subsequent years, only incremental progress was made in understanding their complex and intricate interactions.

During the last decade, however, modern molecular and cell biology techniques have yielded an enormous amount of data detailing the specific components of the immune system and the regulation of the immune or inflammatory response. For instance, redness (rubor), edema (tumor), heat (calor), and pain (dolor) were recognized as the cardinal signs of inflammation more than 2,000 years ago. We now understand that these clinical manifestations are the result of vasodilation with enhanced local blood flow, which causes redness and heat, and increased microvascular permeability, which leads to edema. Extravasation of plasma proteins and leukocyte recruitment to the site of injury generate pain.