Inter-alpha inhibitor proteins

A method for quantifying intact inter-alpha inhibitor protein (IAIP) in a sample from a subject comprising:

• a) contacting the sample with a binding agent to produce an IAIP-binding agent complex, wherein the binding agent is bound to a support, and wherein the binding agent comprises an antibody that specifically binds to bikunin;
• b) contacting the IAIP-binding agent complex with a detection agent, wherein the detection agent comprises an IAIP ligand that binds to at least one IAIP heavy chain and does not bind to free bikunin, and wherein the IAIP ligand is selected from the group consisting of endotoxin (LPS), heparin, a histone, vitronectin, fibronectin, laminin, tenascin C, aggrecan, von Willebrand Factor, pentraxin-3 (PTX3), TNF-stimulated gene-6 (TSG-6), factor IX, a complement component, factor XIIIa, and tissue transglutaminase;
• and
• c) detecting an amount of the detection agent bound to the IAIP-binding agent complex, wherein the intact IAIP comprises bikunin and at least one IAIP heavy chain selected from the group consisting of H1, H2, and H3 chain;
• thereby quantifying the intact IAIP in the sample.