The presence of Epstein-Barr virus (EBV) DNA and antigens was assessed by polymerase chain reaction and immunohistology, respectively, in a total of 92 cases of Hodgkin's disease, angioimmunoblastic lymphadenopathy, CD30-positive anaplastic large cell (ALC) lymphomas, and AIDS-associated atypical lymphoproliferations (ALP). Proportions of the EBV DNA-positive lesions showed latent membrane protein (LMP) expression; some of the LMP-positive ALC lymphomas and ALP cases also displayed EBNA2 immunostaining. BZLF1-protein and gp250/350 immunoreactivity were absent in all instances indicating latent EBV infection. Since the LMP gene has transforming potential, our findings support the concept of a pathoetiological role for EBV in these lymphoproliferative lesions.