CXCL12 and Alzheimer disease: UCB-MSCs from different donors have different effects in enhancing the engraftment of HSCs.104 On the contrary, it has been shown that AD-MSCs compared to BM-MSCs through producing a higher level of C-X-C motif chemokine ligand 12 (CXCL12), further promote HSCs homing and engraftment in a mouse model.105 Van der Garde et al77 in 2015 showed that WJ-MSCs or BM-MSCs in co-transplantation with UCB-HSCs have similarly enhanced effects on hematopoietic recovery into NOD/SCID mice.