HLA-DRB1 and myeloid sarcoma: Improved methods of subtyping HLA loci, as well as studies with increased sample size, have allowed the identification of an extended HLA haplotype, HLA DRB1*15:01, DQA1*0102, DQB1*0602, within the MHC class II region that is strongly associated with the risk of developing MS [9–11].