Epstein-Barr virus

The Epstein-Barr virus (EBV), also called human herpesvirus 4 (HHV-4), is a cancer-causing lymphocryptovirus. There is also strong evidence that the virus has a primary role in the pathogenesis of multiple autoimmune diseases, particularly dermatomyositis, systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome, and multiple sclerosis, and may also be associated with type 1 diabetes mellitus. It is also known to cause several lymphoproliferative disorders and cancers, particularly Hodgkin's lymphoma, Burkitt's lymphoma, nasopharyngeal carcinoma, and central nervous system lymphomas associated with HIV. Most people become infected with EBV and gain adaptive immunity. In the United States, about half of all five-year-olds and 90–95% of adults have evidence of infection. Infants become susceptible to EBV as soon as maternal antibody protection disappears. Many children become infected with EBV, and these infections usually cause no symptoms or are indistinguishable from the other mild, brief illnesses of childhood. In the United States and in other developed countries, many people are not infected with EBV in their childhood years. When infection with EBV occurs during adolescence or teenage years, it causes infectious mononucleosis 35% to 69% of the time. In immunocompromised individuals, the Epstein-Barr virus can also present as an opportunistic infection known as hairy leukoplakia.