T Regulatory Cells and Helicobacter pylori-Associated Diseases

In recent years, a crucial role for T regulatory cells (Tregs) in the pathophysiology of infectious, neoplastic and immune-mediated gastrointestinal diseases has been described. These cells represent a continuously dynamic and diverse population, mainly comprised naturally occurring and inducible Tregs. Multiple mechanisms of immune suppression are utilized by Tregs in order to regulate virtually all immune cells. These peculiar characteristics are being increasingly recognized as important determinants in gut-associated homeostasis and autoimmunity and, in particular, in Helicobacter pylori (H. pylori)-associated diseases. In this regard, Tregs have been implicated not only in the pathogenesis of the immune sequelae of this chronic infection, but also in H. pylori-related malignancies. This review attempts to present a comprehensive approach to Tregs biology and function for preserving homeostasis. In addition, current evidence for their contribution mainly to inflammatory and immune-mediated H. pylori-associated diseases is critically reviewed.