NEFL and myeloid sarcoma: This could explain the observed superiority of the MSC-IT over MSC-IV treatment on the suppression of the NF-L levels in the CSF (and on several other parameters of MS activity, described in our clinical trial12) and may be related to either downregulation of the compartmentalized CNS inflammation (which has been shown to be one of the main mechanisms that drive neurodegeneration and accumulation of disability in progressive MS16) or direct neurotrophic/neuroprotective effects of the MSC on the CNS.