CXCL12 and facioscapulohumeral muscular dystrophy: The expression of CCL5 was elevated in FSHD IM thus CCL5/CCR5 signaling might contribute to MSC homing, but taking into account the overall low expression of CCL5 in FSHD IM and CCR5 in MSCs, this axis only plays an additional role to the CXCL12/CXCR4.