VIROLOGICAL AND IMMUNOLOGICAL STUDIES ON A FATAL CASE OF INFECTIOUS MONONUCLEOSIS

A case of acute, fatal infectious mononucleosis (IM) in a previously healthy man of 34 has been studied. Antibody responses to Epstein-Barr (EB) viral antigens were normal, but there was a marked depression of the peripheral blood T-cell response usually found in acute IM. Ten per cent of the peripheral blood B-cells expressed EB viral nuclear antigen (EBNA) and a cell line established from the peripheral blood lymphocytes was polyclonal in origin, and lacked the lymphoma-associated 8q-:14q+ chromosome abnormality. Post mortem exami nation revealed a massive invasive infiltration of all organs by round cells which included many showing EBNA-positivity and which were polyclonal as judged by surface immunoglobulin typing. Extracts from four out of seven tissues tested were shown to contain transforming EB virus. These results taken together indicate that the EBNA-positive cells found in the blood and tissues of this case of acute IM were in the early stages of a virus replicative cycle rather than transformed by the virus in vivo. The implications of the findings in this T-cell depleted patient are discussed with particular reference to the events occurring in IM in the normal individual. © 1979 The British Society for the Study of Infection.