[Epstein-Barr virus].

Epstein-Barr Virus (EBV) is the prototype member of the human herpesvirus subfamily Gammaherpesviridae. EBV establishes a latent infection in lymphoïd cell and replicates in epithelial cells. Infection of individuals with EBV is widespread in all human populations, as shown by the high proportion of individual with specific antibodies in their serum. EBV is the etiological agent of the infectious mononucleosis and has been implicated in the pathogenesis of an increasing number of human malignancies, the best characterized being endemic Burkitt's lymphomas, nasopharyngeal carcinomas (NPC), and polyclonal lymphomas in immunocompromised patients. EBV infection in vivo is a complex mixture of latent, reactivated, transforming, or replicative type of infection. EBV infection is characterized by sporadic viral excretion in the oropharynx and persistent latent infection in the bone marrow and peripheral blood lymphocytes. EBV infection includes an intense immune response. During primary infection, the humoral response is primarily directed toward antigens of the lytic cycle, membrane antigen complex, early antigen (EA), viral capsid antigen (VCA) while the antibodies response to EBNAs is delayed. The cell mediated response controls the proliferation of EBV-infected lymphocytes through two classes of cytotoxic cells, namely, natural killer and T8 cytotoxic cells. Laboratory diagnosis of EBV infection is recently based upon molecular biology techniques which provides a useful tool for direct identification of EBV and may allow to better understand the role of the virus in the pathogenesis of EBV associated disorders.