The classical view of B cell biology is that these cells respond to foreign and self antigens and in this way promote protection, primarily by production of antibodies. However, recent studies suggest that B cells have diverse functions within the immune system other than antibody production, which could contribute to autoimmunity. This involves organization of lymphoid tissue, regulation of dendritic cells, antigen presentation, activation of T cells and production of cytokines. Both abnormalities in the distribution of B cell subsets, and recent discovery of clinical benefit after B cell depletion highlight the pivotal role of B cells in autoimmunity. This change in view of the role of B cells will be exemplified in one autoimmune disease namely Sjögren's syndrome.