Epstein-Barr virus (EBV) infection is a recognized risk factor that is now regarded as a prerequisite for the development of multiple sclerosis (MS). Recently, significant advances have been made in clarifying the precise mechanism by which EBV leads to the pathogenic features of MS. Now, a new study may have tied up more loose ends. Researchers from the University of Helsinki have mapped the immune landscape of deep cervical lymph nodes (dCLN) in patients recently diagnosed with MS.