HLA-DRB1 and myeloid sarcoma: Given that HLA-DRB1*15:01 is in very strong linkage disequilibrium with HLA-DQB1*06:02 in Europeans, we investigated whether the increased risk of MS in African Americans conferred by European HLA-DRB1*15:01 could possibly be due to HLA-DQB1*06:02, despite the limitation that HLA-DQB1 did not pass our imputation quality cutoff (average R2 = 0.53 across all DQB1 alleles).