Immunohistochemical localization of haptoglobin in porcine lungs.

The extravasation of erythrocytes into the lower respiratory tract occurs in numerous lung injuries and may lead to oxidative damages in lung tissues. Haptoglobin (Hp), the major haemoglobin-binding protein, is known to reduce lung injury associated with exposure to blood in mice. In pigs, Hp is a major acute phase protein and its serum concentrations are elevated in various infections of the respiratory tract.