Infliximab for Crohn's Disease: More Questions than Answers

nfliximab (formerly cA2, Centocor, Inc, USA) is a biological agent that was first reported for the treatment of Crohn’s disease in 1995 (1). It is a chimeric mouse-human immunoglobulin G1 monoclonal antibody to tumour necrosis factor alpha (TNF-α), which is thought to play an important role as a mediator of inflammation in Crohn’s disease. Although it neutralizes TNF, antibody infusions also cause other immunological effects that are less well defined, including changes in cell lysis through complement fixation or antibody-dependent cell-mediated cytotoxicity (2,3). Indeed, in Crohn’s disease tissues, intestinal mucosal cells have been shown to express more TNF (as well as other inflammatory mediators) than healthy individuals (4-6). TNF may regulate some components of the immune response, including those associated with intestinal inflam