Infliximab (Remicade, Centocor, Malvern, Pennsylvania) is a chimeric monoclonal antibody to tumor necrosis factor-α (TNF-α) that is approved by the U.S. Food and Drug Administration (FDA) for treating Crohn disease, rheumatoid arthritis, ulcerative colitis, ankylosing spondylitis, psoriatic arthritis, psoriasis, and pediatric Crohn disease (1). Tumor necrosis factor-α has a central role in both the host immune response to Mycobacterium tuberculosis infection and the immunopathology of tuberculosis (2). In addition, TNF-α production is required for the formation of granulomas, which help to sequester mycobacteria and prevent their dissemination (3). Therefore, it was not surprising that the FDA received adverse event reports of tuberculosis in association with infliximab treatment after the initial marketing of infliximab in the United States in September 1998. These reports were summarized in an article published in October 2001 (4). Coincidentally, a boxed warning was added to the infliximab package insert in October 2001, advising physicians to screen patients for tuberculosis before treatment with infliximab therapy, pretreat those with latent disease, and monitor patients for signs and symptoms of tuberculosis during treatment with infliximab. It should be noted that approved labeling for the 2 other commercially available TNF-α antagonists in the United States, etanercept (Enbrel, Immunex Corporation, Thousand Oaks, California) and adalimumab (Humira, Abbott Laboratories, North Chicago, Illinois), also include warnings about tuberculosis.