2.2. Acute-phase response

The complex series of reactions initiated in response to infection, physical trauma, or malignancy is called the acute-phase response (APR). These reactions aim to prevent ongoing tissue damage, isolate and destroy the infective organism and activate the repair processes necessary to restore the host/organism’s normal function (Baumann & Gauldie 1994). APR is characterized by leukocytosis, fever, alterations in the metabolism of many organs as well as changes in the plasma concentrations of various acute-phase proteins (APPs) (Hack et al. 1997b, Gabay & Kushner 1999). APPs have been defined as any protein whose plasma concentrations increases (positive acute-phase proteins; fibrinogen, serum amyloid A, albumin, C-reactive protein) or decreases (negative acute-phase proteins; albumin, transferrin, insulin growth factor I) by at least 25 percent during an inflammatory disorder (Morley & Kushner 1982). The main stimulators of APP production are the inflammation-associated cytokines, which are produced during inflammatory processes and participate in it: interleukin(IL)-6, IL-1β , tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ ), transforming growth factor β (TGF-β ) and possibly IL-8 (Kushner 1993, Wigmore et al. 1997, Gabay & Kushner 1999). The local inflammation in both cancer and infection is accomppanied by APR upon activation by cytokines (Cavaillon & Duff 1999).