Evaluation from the Food and Drug Administration Adverse

Interferons are pleiotropic cytokineswith important immunomodulatory, an-tiviral, antiangiogenic, antiproliferative, and antitumor functions.1 There are 2 major groups of interferons, type I and type II. Type I interferons are structurally related, share a common receptor (type I interferon receptor), and play an impor-tant role in immunity and autoimmunity. They are related to the pathogenesis of autoimmune conditions, and this autoim-mune effect has been utilized in several medications. Specifically, type I interfer-ons initiate cellular reactions that result in a host-protective antiviral response. Type I interferons include interferon alfa (IFN-α), approved by the Food and Drug Administration (FDA) for the treatment of the hepatitis C virus (HCV), and interferon beta (IFN-β), approved for multiple sclerosis (MS).2 There are 11 type I interferon medica-tions available, including IFN-α-2a (Ro-feron-A), IFN-α-2b (Intron-A), IFN-α-n3 (Alferon-N), peginterferon alfa-2b (PegIn