Key Points The complement system is a group of circulating proteins that promote inflammation and host defense. Unregulated tissue damage is a possible complication of complement activation; a large variety of circulating and membrane-bound proteins exist to regulate complement activity.…
Key Points Five different classes of antibody are known—immunoglobulin (Ig) M, IgG, IgA, IgD, and IgE—each with a distinct heavy chain. Two different light-chain types have been identified: κ and λ. Antigens react with antibodies at the Fab region, which…
KEY POINTS Humoral immune tests assess production of specific antibody responses to past or recent infections, and cellular immune assays measure current immune responses. The immune system changes with age and nutritional status. Differences in immune responses of test subjects…
Key Points Antigens can have a wide variety of types of chemical composition such as proteins, carbohydrates, and lipids. They can range in size from very small molecules, such as hormones, to very large ones on viral or bacterial particles.…
Key Points The immune system consists of cellular and humoral components that defend the body against invading microorganisms. Deficiency of individual factors of the immune system can leave an individual susceptible to different infections. The lymphoid cells of the immune…
Key Points Warfarin has historically been the most commonly used oral anticoagulant. It is a vitamin K antagonist and blocks γ-carboxylation of a series of glutamic acid residues during the synthesis of factors II, VII, IX, and X, and proteins…
Key Points Several regulatory mechanisms have evolved to limit the extent of clot formation after coagulation is triggered. Under normal conditions, these allow hemostasis to be achieved while preventing the growth of a hemostatic plug into an intravascular thrombus. Among…
Key Points Platelets are highly complex cells that participate in critical steps central to hemostasis and thrombosis, including adhesion to subendothelium, aggregation, secretion of granule contents, and provision of membrane surface for activation of coagulation factors. Abnormalities of either platelet…
Key Points Physiologic hemostasis consists of endothelium, platelets, plasma coagulation proteins, natural anticoagulants, and the fibrinolytic system. Primary hemostasis involves platelets and von Willebrand factor. Secondary hemostasis is initiated by the tissue factor pathway and then amplified and propagated by…
Key Points A wide range of allogeneic tissues are used for transplantation. Allograft tissue is screened, tested, and processed to improve its safety. Allograft tissue is stored by a variety of methods, including cryopreservation. Risks and complications are associated with…