The findings showing that DQB1*0602 determines pathogenic autoimmunity against PLP and MOBP [28], together with previously reported studies showing that DRB1*1501 determines pathogenic autoimmunity against MBP and MOG [24,27] suggest a more complex and differential genetic predisposition to HLA-DR15+ MS, depending on the primary CNS target antigen/epitope against which the pathogenic autoimmunity is primarily directed, or triggered (genotype/antigen/phenotype relationship). This evidence concerns the gene MBP and myeloid sarcoma.