Epstein Barr virus infection and immune defense related to HLA-DR15: consequences for multiple sclerosis

MS is a multifactorial disease in which a series of genetic and non-genetic, environmental factors plays a role in its etiology. In particular, HLA class II alleles, mainly HLADRB1*15:01 (HLA-DR15), increase the risk for this disease. Out of several environmental factors, and with regard to infections, EBV remains to be a strong candidate, and may synergize with HLA-DR15 thus increasing the risk for MS. In this issue of the European Journal of Immunology, Zdimerova et al. present highly interesting experimental data using EBV infection in immune-deficient mice engrafted with human immune cells, either HLA-DR15⁺ or HLA-DRB1*04:01 (HLA DR4), here after denoted as HLA-DR15^- . As a result of EBV infection, the viral load and CD8⁺ cell expansion were conspicuously higher in mice engrafted with HLA-DR15⁺ compared to HLA-DR15^- mice; and myelin basic protein specific T cells emerged in mice engrafted with HLA-DR15 bearing cells. This study sheds light on how EBV and the class II DR15 haplotype may jointly predispose and synergize in the etiology of MS.