T Regulatory Cells in Inflammatory Bowel Disease-Are They Major Players?

Inflammatory bowel disease (IBD) is a chronic condition whose pathogenesis is not entirely clear. Impaired immune regulation has been hypothesized as the mechanism responsible for the abnormal response of adoptive immunity to enteric microbial antigens. Regulatory T cells (Tregs) have been regarded as the crucial element of immune regulation, since the discovery that humans lacking Tregs due to mutation of FOXP3 develop autoimmune disorders, including severe bowel inflammation. The existing publications concerning T regulatory cells in human IBD have been reviewed, and current evidence does not clearly indicate quantitative disturbances or functional defects of Tregs in human inflammatory bowel disease. The possible mechanisms explaining immunoregulatory failure in IBD have been summarized. So far, only one clinical trial with Tregs infusion has been completed, and its results do not provide sufficient data on the efficacy or safety of Tregs-based therapies in IBD. It will probably be difficult to implement them in clinical practice in the near future.