More recent studies showed that individuals with incomplete haplotypes bearing only HLA-DRB1*15:01 or HLA-DQB1*06:02 were not predisposed to MS; the HLA-DQA1*01:02, which by itself shows no primary association with MS, increases the risk of MS when combined with HLA-DRB1*15:01 in trans, and plays a protective role in the absence of HLA-DRB1*15:01 (20). This evidence concerns the gene HLA-DRB1 and myeloid sarcoma.