Moreover, we found an interaction between both the DRB1*15:01 and absence of HLA-A*02 (the extended HLA haplotype confirming the highest risk for MS) with IE1A only in persons with high EBV levels, and an interaction of DRB1*15:01 with IE1B only in persons with low EBV levels. The gene discussed is HLA-DRB1; the disease is myeloid sarcoma.