Antibodies Against Acute Phase Proteins

Twenty-five antibodies against acute phase proteins (anti-APPs) have previously been described and indicated to be important in autoimmunity and other diseases. The developed anti-APPs' repertoire indicates a possible fingerprint of targeted pathophysiologic processes in diseases. Presently, there are some clinically interesting anti-APPs, such as autoantibodies against β2 glycoprotein I (β2-GPI) for diagnosing antiphospholipid syndrome, antibodies against citrullinated fibrinogen for diagnosing early rheumatoid arthritis, and autoantibodies to complexes of β2-GPI/oxidated low density lipoproteins relevant for atherosclerosis and arterial thrombosis in autoimmune patients. Antibodies against C1 inhibitor are characteristic of patients with acquired C1 inhibitor deficiency and recurrent symptoms of angioedema, but have also been found increased in systemic lupus erythematosus. Autoantibodies against pancreatic secretory trypsin inhibitor can be a useful diagnostic marker of autoimmune pancreatitis. Hemophilia A was the first disease where factor VIII hydrolysis was reported by their abzymes (catalytic antibodies) and clinical manifestations were established. In contrast, a synthetic anti-von Willebrand factor nanobody, ALX-0081, was found to be a safe, well-tolerated, and efficacious inhibitor of platelet aggregation that could be suitable for the treatment of stable angina patients. A phase II clinical trial is currently under way to assess the efficacy of the anti-von Willebrand factor nanobody and safety in patients with acquired thrombotic thrombocytopenic purpura.