HLA-DRB1 and myeloid sarcoma: MSSS was lower in southern MS patients with HLA-DRB1*04:05 than in those without the allele when excluding PPMS in this study, which is in accord with a previous finding that HLA-DRB1*04:05 was associated with a milder disease course as evaluated by EDSS scores and PI in Japanese MS patients, particularly from southern Japan11,13.