HLA-DRB1 and myeloid sarcoma: Although we recently reported a statistical interaction between EBV antibody response and HLA-DRB1*15:01,6,14 the primary genetic risk for MS, how the broader genetic factors governing EBV-associated host response and IM risk relate to that of MS susceptibility is not well understood.6,15 This study identifies genome-wide and HLA-specific risk factors associated with high EBV antibody levels and IM history using large MS case-control cohorts from the Swedish population.