As it has been demonstrated that CD46 is selectively and progressively downregulated from the target cell surface during the course of HHV-6 infection [39], the increased levels of CD46 expression reported in this study in patients with MS with HHV-6 infection could be related to the increased levels of the soluble form of CD46 described in patients with MS [44, 45], and, therefore, this could constitute an immunopathogenic factor that should be investigated in MS. Here, CD46 is linked to myeloid sarcoma.