HLA-DRB1 and myeloid sarcoma: Moreover, despite the strong association of DRB1*1501 with MS, the majority (∼59%) of genetically susceptible individuals are susceptible based on genotypes that do not include this allele and, indeed, for the 25% of these individuals who, nonetheless, still carry this allele, the presence of DRB1*1501 seems not to contribute to their susceptibility (Prop.