Low-grade inflammation is an immune system response. When the body detects injurious stimuli, there can be a neuroendocrine response such as fever, a blood response, and a metabolic response. Initially, the innate (instinctive) immune system responds. White blood cells as well as cytokines work together to fight against the injury. Interleukins and tumor necrosis factor-alpha are important substances that assist in a wide variety of inflammatory reactions. The release of these substances leads to the production of acute phase reactants like fibrinogen, sialic acid, and C-reactive protein. If the injurious stimuli persist, many acute phase reactant levels remain elevated.
The inflammatory process in the endothelial lining of blood vessels as well as adipose tissue (fat) and skeletal muscle are of particular interest. Clinically, low-grade inflammation is defined as a two to four-fold elevation in circulating levels of proinflammatory and anti-inflammatory cytokines as well as numerous other markers of immune system activity.
Interleukins are substances in the blood that act as messengers and are critical to the functioning of the immune system. Interleukin-6 is involved in the pro-inflammatory response and is secreted by white blood cells to stimulate immune response to trauma. For more information click here
C-Reactive Protein works with antibodies in the body to fight infection. It is produced in the liver and levels can be measure in the blood. It is thought to be mediated by cytokines produced by fat cells. It has become a common clinical test as a marker of low-grade inflammation and increased risk of cardiovascular disease. See Associated Diseases for more information on clinical testing. For more information click here
Tumor Necrosis Factor-alpha is another important substance that acts to stimulate immune system response to injury or invasion. When stimulated in the liver it leads to an increase in C-reactive protein and many other mediators. It acts on other tissues to increase insulin resistance. For more information click here