HLA-DRB5 and myeloid sarcoma: HLA‐DRB5*01:01 has been indicated to modulate the presumed disease promoting HLA‐DRB1*15:01 antigen‐presentation since rare HLA‐DRB5*null haplotypes among HLA‐DRB1*15:03 African‐American MS patients correlated with an increased risk of developing severe secondary progressive MS (Caillier et al., 2008).