HLA-DRB1 and myeloid sarcoma: Agliardi et al. [22], in a case-control including 187 MS patients and 197 controls HLA-DRB1*15-positive and 454 MS patients and 363 controls HLA-DRB1*15-negative, found a modest decrease in the risk for MS in HLA-DRB1*15-positive subjects carrying the rs731236TT genotype or the rs731236T allele.