Acute Phase Reactants (APRs) constitute a group of proteins that undergo rapid changes in blood serum concentration in response to inflammation or tissue injury. These changes are markers of the body's acute-phase response, a systemic reaction aimed at addressing infections, injuries, and other forms of stress. APRs are synthesized mainly by the liver and play roles in modulating the immune response, inflammation, tissue repair, and overall homeostasis. CRP is one of the best-known acute phase reactants. It is produced by the liver in response to cytokines, particularly interleukin-6 (IL-6) which is released during inflammation. Elevated levels of CRP in the blood are indicative of various inflammatory conditions, including infections, tissue damage, and chronic inflammatory diseases like atherosclerosis. CRP assists in the activation of the complement system, which is part of the immune response, and it also binds to damaged cell membranes, promoting phagocytosis and clearance of cellular debris. Fibrinogen is a precursor protein involved in blood clotting. During inflammation, its serum levels increase as part of the acute-phase response, with hepatocytes in the liver responding to IL-6 by increasing the synthesis of fibrinogen and secreting larger quantities of it into the bloodstream. Fibrinogen's conversion to fibrin forms the basis of blood clot formation. Elevated fibrinogen levels also contribute to an increased risk of thrombosis, which can lead to cardiovascular events like heart attacks and strokes in atherosclerosis. Serum Amyloid A (SAA) are a family of proteins that are mainly produced by the liver. They play a role in inflammation, lipid metabolism, and tissue repair. SAA acts as a chemoattractant for various immune cells, including monocytes, neutrophils, and macrophages. It helps to guide these immune cells to the site of inflammation, where they can participate in the immune response, phagocytosis, and tissue repair. SAA can also activate immune cells through interaction with Toll-like receptors (TLRs) such as TLR2 and TLR4. This activation leads to the production of pro-inflammatory cytokines and other immune mediators, amplifying the inflammatory response. Increased SAA levels are associated with both acute and chronic inflammatory conditions. Haptoglobin binds to free haemoglobin released from damaged red blood cells, preventing oxidative damage and kidney filtration. During inflammation, haptoglobin levels increase, reflecting the need to scavenge excess haemoglobin generated due to tissue damage or haemolysis. Alpha-1 antitrypsin (AAT) is a serine protease inhibitor that helps regulate the activity of other proteases released during inflammation. Elevated AAT levels counteract excessive protease activity, protecting tissues from damage caused by uncontrolled inflammation. Procalcitonin (PCT) meanwhile is a precursor of the hormone calcitonin and is produced by various tissues, including the liver in response to bacterial infections. PCT levels rise significantly during bacterial infections and sepsis, making it a useful marker for differentiating bacterial infections from other causes of inflammation. Finally, ferritin is an intracellular protein responsible for storing and releasing iron. During inflammation, ferritin levels increase as part of the acute-phase response. Elevated ferritin levels may indicate conditions like infections, inflammatory disorders, or certain malignancies. We provide a wide product catalogue of research reagents for investigating acute phase reactants, including Serum Amyloid A antibodies, C Reactive Protein antibodies, Ceruloplasmin antibodies, C Reactive Protein ELISA Kits, and Alpha 1 Acid Glycoprotein ELISA Kits. Explore our full acute phase reactants product range below and discover more, for less.