Targeting costimulatory molecules expressed by several immune cells could offer an alternative treatment strategy for DAOSD where signalling pathways other than Th2 are involved, and recent mouse studies comparing CD30L (TNFSF8) and OX40 ligand (OX40L; TNFSF4) suggest CD30L might be an effective target for downregulating AD [37]. Here, TNFSF8 is linked to Alzheimer disease.