HLA-DRB1 and myeloid sarcoma: There are several overlapping HLA variants, including DRB1*08:01, DQB1*03:01 and particularly the DRB1*15:01 and DRB1*03:01 haplotypes, which are not only the primary genetic associations for EBV serology but also for MS.6,14,23 Interestingly, although both alleles DRB1*15:01 and DRB1*03:01 are associated with higher MS risk, DRB1*03:01, unlike DRB1*15:01, is associated with lower EBV antibody levels, possibly indicating different mechanisms of association.