BAFF, APRIL and human B cell disorders.

B cells require signals from multiple sources for their development from precursor cells, and differentiation into effector cells. BAFF has been identified as a critical regulator of B cell development and differentiation. Defects in the production of BAFF and/or expression of its receptors have been associated with a diverse array of human immunopathologies characterised by perturbed B cell function and behaviour, including autoimmunity, malignancy, and immunodeficiency. This review will discuss the role of BAFF in the pathogenesis of these human immune disorders. It will also highlight relevant differences between the function of BAFF in humans and mice and the impact of this on the therapeutic utility of BAFF antagonists in the treatment of different human diseases.