Recombinant protein technology and the subsequent development of biologic agents for pharmacotherapy have greatly improved the treatment of a wide variety of diseases in humans. These products are subject to reactions not previously seen in other drug classes.
Additionally, subtle alteration in the manufacture or administration of a biologic agent may cause reactions in subjects who previously tolerated it. This review highlights the unique immunologic reactions that are associated with the more commonly used biologic agents.

Key words: Biologic agents. Neutralizing antibody. Recombinant protein. Monoclonal antibody