HLA-DRB1 and myeloid sarcoma: We did not find significance for the previously identified African allele, HLA-DRB1*15:03 at the pre-specified significance level of 1.0 x 10−04; however, after conditioning on the three independent African classical alleles, marginal significance was seen (OR = 1.23, p = 2.53 x 10−02), indicating that HLA-DRB1*15:03 does contribute to MS risk within this sample.