Incidence of Hypersensitivity Reactions

Background. Aprotinin is a naturally occurring serine protease inhibitor derived from bovine lung. In common with all foreign proteins, it possesses antigenic properties and has the possibility of allergic reactions on reexposure. Methods. Data are presented on the incidence of adverse reactions to aprotinin and the time course of antibody development after initial exposure. Recommendations for reducing the risk and sequelae of these adverse reactions are emphasized and case reports are reviewed. Results. The incidence rates of aprotinin-related reactions to date (May 1997) at the German Heart Center are 2.7% in the adult population in reexposures (5/183) and 1.2% in the pediatric population (3/254), with an overall incidence of 1.8% (8/437). Conclusions. With the recommended precautions, reexposure to aprotinin in patients with a high risk of bleeding is justified, and the benefits of aprotinin treatment outweigh the relative risk of a serious allergic reaction.