Haptoglobin is a glycoprotein, which is synthesized in the liver and circulates in the blood. Haptoglobin is usually produced by liver cells, but it is also produced by other tissues, such as skin, lung and kidney. It is a positive acute phase protein, which binds to free hemoglobin and removes it from circulation to prevent kidney injury and iron loss after hemolysis. Decreased levels can be seen in hemolysis and impaired liver function. A high level is a sign of acute or chronic inflammation. Hemoglobin deficiency or hypohaptoglobinemia is caused by mutation of haptoglobin gene and/or its regulatory region. Haptoglobin is also related to diabetic nephropathy, the incidence of coronary artery disease in type 1 diabetes, Crohns disease, inflammatory disease behavior, susceptibility to primary sclerosing cholangitis, idiopathic Parkinsons disease and the reduction of the incidence of plasmodium falciparum malaria.
