We used the Japan MS/NMOSD Biobank and the largest cohort of Japanese MS and NMOSD patients studied to date to show that HLA-DRB1*04:05, DRB1*15:01 and DPB1*03:01 are susceptibility alleles, while HLA-DRB1*01:01, DRB1*09:01, DRB1*13:02 and DPB1*04:01 are protective alleles for MS, which is consistent with previous Japanese studies on MS11,13. Here, HLA-DRB1 is linked to myeloid sarcoma.