Macrophages sense bacterial products through Toll-like receptors (TLR) and regulate the inflammatory response. Negative acute phase reactants include albumin, prealbumin, transferrin, retinol-binding protein, and antithrombin. Positive acute phase reactants include procalcitonin, C-reactive protein, ferritin, fibrinogen, hepcidin, and serum amyloid A. Negative acute phase reactants are downregulated, and their concentrations decrease during inflammation. Positive acute phase reactants are upregulated, and their concentrations increase during inflammation. These include fever, anemia of chronic disease, anorexia, somnolence, lethargy, amyloidosis, and cachexia (fat and muscle loss, anorexia, weakness).Īcute phase reactants can be classified as positive or negative, depending on their serum concentrations during inflammation. Acute phase reactants cause several adverse effects. IL-1, tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) can also induce the production of acute-phase reactants. Interleukin-6 (IL-6) is the primary cytokine responsible for inducing the production in the liver. These are also important mediators produced in the liver during acute and chronic inflammatory states. Acute phase reactants (APR) are inflammation markers that exhibit significant changes in serum concentration during inflammation.
