The BAFF system plays a key role in the development of autoimmunity, especially 
in systemic lupus erythematosus (SLE). This often leads to the assumption that 
BAFF is mostly a B cell factor with a specific role in autoimmunity. Focus on 
BAFF and autoimmunity, driven by pharmaceutical successes with the recent 
approval of a novel targeted therapy Belimumab, has relegated other potential 
roles of BAFF to the background. Far from being SLE-specific, the BAFF system 
has a much broader relevance in infection, cancer and allergy. In this review, 
we provide the latest views on additional roles of the BAFF system in health and 
diseases, as well as an update on BAFF and autoimmunity, with particular focus 
on current clinical trials.