Natural Treg in autoimmune diabetes: all present and correct?

BACKGROUND: The critical role for regulatory T cells (Treg) in suppressing autoimmune pathology is now well recognised. However, the extent to which defects in regulation can be blamed for the onset of diseases like type 1 diabetes is not clear. OBJECtive: To collate the available data from mouse models and from studies of type 1 diabetes patients, with a view to understanding the status of the natural Treg compartment in this disease setting. RESULTS/CONCLUSION: Available evidence suggests that natural Treg are not under-represented in type 1 diabetes, and that Treg function is only likely to be suboptimal in a subset of patients. Emerging therapeutic strategies that attempt to exploit our knowledge of Treg biology to restore effective immune regulation in type I diabetes are discussed.