Circulating Follicular Regulatory T Cells in Autoimmune Diseases and Their Waning in Multiple Sclerosis

Follicular regulatory T cells (T(FR)s) are a subset of regulatory T cells that reside in the secondary lymphoid organs and participate in controlling the germinal center (GC) response. The GC response forms the basis of adaptive immunity to foreign protein antigens. In autoimmune diseases, hyperreactivity to self-antigens occurs that may result from an aberrant control of the GC response. T-FR dysfunctionality may be one of the factors contributing to this breakdown of self-tolerance. In this review, we discuss how the investigation of circulating TFRs can help us understand their relative contribution to autoimmune-mediated disease processes. Multiple sclerosis is taken as a classical example of autoimmune disease.