What is the practical significance of antibodies to interferons?

Interferons are generally recognised as the treatment of choice in some infectious diseases, such as chronic hepatitis B and C. Since the early clinical trials it was documented that the therapeutic use of interferons could be complicated by the development of antibodies able to neutralise or to bind to the interferon molecule. This finding is not surprising if one considers that natural or therapy-induced antibodies to interleukin (IL)-1, IL-2, IL-6, IL-10, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, insulin and recombinant factor VIII have been reported in humans. Since hormones, cytokines, biological response modifiers and homeostatic agents are being used for the therapeutic management of many infectious, autoimmune and neoplastic diseases, the possibility that therapy-induced antibodies can develop in humans should be considered. In this article we summarise what is currently known about the clinical significance of antibodies to interferons in interferon-treated patients. The presence of circulating antibodies may affect the response to interferon. Antibody development may be clinically significant, depending on the titre and the time of appearance. In particular, the response to interferon therapy may be affected by antibodies when they appear early in therapy and at high titre.