Haptoglobin and Hemopexin in Heme Detoxification and Iron Recycling

The acute phase reaction is an early response aimed at the defence of the organism and at the re-establishment of homeostasis in response to acute infection, inflammation and other pathological states (Kushner, 1982). The putative mechanism responsible for this reaction is based on an initial signal derived from macrophages and other cells that synthesize and secrete several factors (probably cytokines) capable of inducing, in hepatocytes, a series of events. One of the most important mediators of the liver acute phase response is the monokine Interleukin (IL)-6 (Gauldie et al., 1987). The acute phase response consists in a change in the concentration of several plasma proteins, generally synthesized in the liver, including 1-glycoprotein (AGP), complement factor C3, serum amyloid A, Haptoglobin and Hemopexin.