TNFSF13B and systemic lupus erythematosus: EBV may finally cause a defect in B cell tolerance checkpoints, as shown in transgenic lupus mouse models by the induction of B cell activating factor of the tumor necrosis factor family (BAFF), also known as a B lymphocyte stimulator, a vital homeostatic cytokine for B cells that helps regulate both innate and adaptive immune responses [22].