TNFSF13B and myeloid sarcoma: The purpose of this study was to determine whether BAFF levels: (i) were increased in MS patients in comparison to other neurological diseases (OND) and HC, (ii) were modified after Methylprednisolone therapy in MS patients (iii) were correlated to the humoral response against peptides from infectious agents, previously associated to MS: Epstein-Barr Virus (EBV) and Mycobacterium avium subsp.