Inter-α-Inhibitor (IαI) Concentration in Pig Plasma Is Independent of Acute-Phase Protein Response

Abstract Human inter-α-inhibitor (IαI) has been shown to exert a beneficial therapeutic effect in a porcine model of endotoxin shock. It is therefore useful to have a better understanding of IαI metabolism during severe inflammatory syndromes. Experimental bacterial pneumonia was induced in pigs. The acute phase response was highlighted by an increase in pig major acute phase protein (pig-MAP) and haptoglobin concentrations in plasma collected daily over 4 days. In the same samples, the IαI levels remained unchanged. Moreover, crossed-immunoelectrophoretic and immunoblot analyses did not show any qualitative modification of IαI throughout the experiment. IαI has been reported to be a negative acute phase protein in both humans and rats. Here we demonstrated that IαI behavior clearly differs in humans and pigs and is definitively species specific.