Future Targets for Immune Therapy in Colitis?

Abstract

Crohn's disease and Ulcerative Colitis, collectively termed inflammatory bowel disease (IBD), are chronic inflammatory disorders of the bowel. It is generally accepted that the pathology associated with IBD is characterized by a hyper-reactive immune response in the gut wall directed against the commensal intestinal bacterial flora, and that the CD4+ T cells dominate the adaptive immune response. Chemokines are small proteins involved in the guidance of migration of immune cells during normal homeostasis and inflammation. Chemokines have been shown to play a central role in recruiting inflammatory cells to the inflamed bowel of IBD patients, making the chemokine/receptor system appealing as new therapeutic targets to sustain remission in these patients. In the severe combined immunodeficiency transfer model of colitis, which histopathologically resembles human IBD, low numbers of CD4+CD25- T cells from congenic normal mice are transplanted into immune deficient mice, which in turn develop a chronic lethal colitis within 1-2 months. By simultaneous transplantation of CD4+CD25+ regulatory T cells (Tregs) it is possible to hinder development of colitis. Thus the model is well suited for studying mechanisms underling both the effector and the regulatory components of chronic inflammation. In the current review we discuss new possible targets for immune therapy in colitis.