B cell-activating factor (BAFF) system molecules modulate a variety of biological processes, including cell survival, differentiation, and other effector functions, as demonstrated in some autoimmune diseases, such as systemic lupus erythematosus (SLE), Sjögren’s syndrome (SS), and systemic sclerosis (SSc) (50–52). The gene discussed is TNFSF13B; the disease is systemic sclerosis.