HLA-DRB1 and myeloid sarcoma: After adjusting for the geographic region (northern vs. southern), sex, age at onset, MS subtype, disease duration, ARR, EDSS, HLA-DRB1*04:05, and HLA-DRB1*15:01, we observed a positive correlation between living at a higher latitude and the presence of Barkhof brain lesions (adjusted OR = 1.63, p = 0.0434) and a negative correlation between HL-DRB1*04:05 and Barkhof brain lesions (adjusted OR = 0.49, p = 0.0043).