Thus, impaired recognition of EBV-infected or latent EBV-infected cells by CD4 T cells in individuals with the HLA-DR15 allele may result in uncontrolled expansion of CD8 T cells and increased production of anti-EBNA-1 antibodies, contributing to infectious mononucleosis and the development of multiple sclerosis (122, 299, 300). This evidence concerns the gene CD8A and infectious mononucleosis.