The case report that is the subject of this Commentary describes a 27-year-old woman, who, 3 months after a devastating low cervical myelitis, underwent intrathecal mesenchymal stem cell (MSC) infusions. Six hours after the third infusion, she became unconscious, febrile and cerebral MRI showed acute bitemporal and left cerebellar lesions, consistent with an acute disseminated encephalomyelitis. It is likely that this is the first reported patient with neuroinflammatory exacerbation after MSC therapy. This case suggests that, in addition to their malignant potential, autologous MSC expanded in vitro can exhibit immune-activating properties leading to autoimmune exacerbation.