Acute phase reaction

Systemic response of vertebrates to tissue damage e.g. trauma, burns, infections, neoplasia, ischemia and autoimmune diseases. The acute-phase reaction is used to create optimal conditions for repair processes and, in the case of an infection, to defend against microorganisms. Characteristic features are: leukocytosis with increased occurrence of immature rod nuclear granulocytes (left shift).

APR is mainly activated by cytokines. The endogenous pyrogenic tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1 adjust the set point of the body temperature regulation in the hypothalamus. Furthermore, APR is accompanied by general symptoms such as muscle trembling (chills), feeling of illness and loss of appetite. At the cellular level, leukocytosis occurs with left-shifting (effect of granulocyte-macrophage colony stimulating factor - GM-CSF), platelet aggregation, edema and mast cell degranulation with release of mediators. APR leads to an increase in the concentration of positive acute-phase proteins (also acute-phase proteins) or to a decrease in the concentration of the rarer negative APPs (e.g. albumin). Acute-phase proteins are primarily synthesized in the liver.

Other regulatory proimmflammatory cytokines are Interleukin-8 and GM-CSF. Interleukin-4, Interleukin-10 and the Transforming Growth Factor-β (TGF-β) have inhibitory effects.