Possible explanations for a causal relationship between CMV infection and ABMR include the following: CMV induces the expression of B-cell activating factor (BAFF), a cytokine involved in B-cell homeostasis that communicates survival and growth signals to B cells and virus-specific plasma cells via the BAFF receptor, TACI (the calcium modulator, the cyclophilin ligand interactor), and B cell maturation antigen (BCMA) receptors. Here, TNFSF13B is linked to cytomegalovirus infection.