HLA-DRB1 and myeloid sarcoma: In countries like Sardinia, Japan and Turkey where about five times higher ratios of OCB negative/OCB positive MS are reported compared to Northern Europe, MS risk has been shown to be conferred by both HLA-DRB1*04 and HLA-DRB1*15∶01 [10], [12], [19], [41], [42].