The HLA class-II linkage in MS differs in various populations, but the highest association is with HLA-DR2 (DRB1 × 1501)/DQ6 (DQB1 × 0602),57 followed by DR3/DQ2 and DR4/DQ8 haplotypes.6,55,58 A study involving 3,002 public human gut microbiota datasets showed that individuals with functionally similar HLA haplotypes are also similar in the microbiota composition,59 suggesting a possible linkage between genetics and the microbiome in MS predisposition. Here, HLA-DRB1 is linked to myeloid sarcoma.