HLA-DRB1 and myeloid sarcoma: Since in our case–control study HLA-DRB1*15:01 allele was strongly associated with MS (for HLA-DRB1*15:01−/+ OR = 2.66; 95% CI = 1.86–3.75; p < 0.0001 and for HLA-DRB1*15:01+/+ OR = 4.34; 95% CI = 1.61–12.73; p = 0.006) (Wagner et al. 2014b) and stratification for HLA-DRB1*15:01 is expected to help to reveal the associations with MS susceptibility (Bronson et al. 2010; Kikuchi et al. 2002), the presence of this allele was also taken into consideration.