DRB1*04:05 had a strong negative association with CSF IgG abnormalities (and adjusted OR = 0.39, p = 0.0004, respectively) after adjusting for geographic region (northern to southern), sex, age at onset, MS subtype, ARR, EDSS, HLA-DRB1*04:05, and HLA-DRB1*15:01. This evidence concerns the gene HLA-DRB1 and myeloid sarcoma.