T follicular helper (Tfh) cells in autoimmune diseases

Systemic autoimmune diseases are characterized by multiple organ damages, whose pathogenesis caused by the activation of autoreactive T cells reacting against antigens of the body's own tissues and B cells producing autoantibodies. Following the animal studies, Tfh cells have been identified as a critical subset for the formation and function of B cell responses in humoral immunity, but also play an important role in autoimmunity. In fact, circulating Tfh cells are reported to increase and correlate with disease activity and autoantibody production in human autoimmune diseases. However, the evidence from human studies highlighted apparent differences between mouse and human Tfh cell differentiation. Furthermore, there is increased recognition of functional plasticity and diversity of Tfh cells. This may be advantageous in terms of host defense but needs to be borne in mind in thinking about effective therapies for autoimmune diseases. Thus, better understanding of the extrinsic and intrinsic signals that control plasticity and diversity of Tfh cells will have important therapeutic applications to control autoimmunity.