One of these hallmarks of human immunosenescence associated with long-term CMV infection is the oligoclonal expansion of late-stage differentiated effector memory or effector T-cells, characterised by the downregulation of co-stimulatory molecules such as CD27 or CD28 and the expression of markers as KLRG-1 and CD57 [25]. Here, B3GAT1 is linked to cytomegalovirus infection.