Acute-phase proteins are a class of
proteins whose
plasma concentrations increase (positive acute-phase proteins) or decrease (negative acute-phase proteins) in response to
inflammation. This response is called the
acute-phase reaction (also called acute-phase response). In response to injury, local
inflammatory cells (
neutrophil granulocytes and
macrophages) secrete a number of
cytokines into the bloodstream, most notable of which are the
interleukins IL1,
IL6 and
IL8, and
TNFa. The
liver responds by producing a large number of
acute-phase reactants. At the same time, the production of a number of other proteins is reduced; these are, therefore, referred to as "negative" acute-phase reactants. Increased acute phase proteins from the liver may also contribute to the promotion of
sepsis.