Regulatory B cells: Development, phenotypes, functions, and role in transplantation.

The interest in regulatory B cells (Bregs) began in the 1970s with the evidence that B cells could downregulate the immune system by the production of "inhibitory" antibodies. Subsequently, a series of results from different studies have emphasized that B cells have antibody-independent immunoregulatory functions. Since then, different subsets of B cells with regulatory functions and their development and mechanisms of action have been identified both in human and in animal models of inflammation, transplantation, and autoimmunity.