Why do anti-tumor necrosis factor antibodies work in Crohn's disease?

Anti-tumor necrosis factor (TNF) antibodies are powerful therapeutic agents for the treatment of Crohn's disease. TNF has diverse proinflammatory effects within the intestinal mucosa and is a pivotal cytokine in the inflammatory cascade. Although anti-TNF antibodies exert a variety of anti-inflammatory effects by neutralizing the cytokine, these agents vary in their efficacy. Recent data suggest that the ability to bind transmembrane TNF is a key property necessary for efficacy. Transmembrane binding of TNF effects apoptosis of T cells, thereby alleviating a fundamental defect in Crohn's disease in the regulation of T cell populations.