Epstein-Barr virus: the spectrum of its manifestations in human beings.

Epstein-Barr virus (EBV) infects virtually everyone by adulthood, and a lifelong latency is maintained. It infects children silently, whereas the majority of adolescents have infectious mononucleosis (IM). Children who have IM before 5 years of age are often heterophil negative; EBV-specific antibodies are required for diagnosis. On rare occasions the symptoms of IM may persist in a chronic or recurrent form, and fatal infectious mononucleosis occurs rarely. Depending on the type and degree of immune deficiency and the time the EBV infection occurs in the life cycle, various atypical outcomes can occur. Children with primary immune deficiency can have fatal or chronic IM, malignant B cell lymphoma, virus-associated hemophagocytic syndrome, aplastic anemia, or acquired hypogammaglobulinemia. The various outcomes of the EBV infections are likely governed by the immune response of the individual. The increased frequency of B cell neoplasms in immunodeficient patients is likely due, in part, to EBV. Individuals with acquired immune deficiency disorders such as AIDS or allograft recipients may develop malignant B cell lymphomas which tend to be polyclonal, but which may progress through stages of oligoclonality to monoclonality. This conversion likely results from specific reciprocal chromosomal translocations such as t(8;14), which is seen in Burkitt's lymphoma. Detection of EBV in immunodeficient patients is achieved by EBV-specific antibody studies or isolation of virus by obtaining spontaneous lymphoblastoid cell lines from peripheral blood, isolating virus from throat washings, or identifying EBV genome by molecular hybridization techniques. Prevention of primary immune deficiency by early detection and genetic counseling and monitoring of patients for occurrence of EBV infection may lead to early treatment. Acyclovir and immunoglobulin therapy can be of value in some patients with active EBV infection.