Background. Children with the acquired immunodeficiency syndrome (AIDS) have an unusually high incidence of smooth-muscle tumors (leiomyomas and leiomyosarcomas) in addition to malignant lymphomas. We tested the hypothesis that the smooth-muscle tumors in these children are associated with the Epstein-Barr virus (EBV). Methods. Tissue specimens of five leiomyosarcomas and two leiomyomas from five children and one young man with AIDS were studied for evidence of the human immunodeficiency virus (HIV) and EBV by in situ hybridization and quantitative polymerase chain reaction (PCR). Comparison specimens included samples of leiomyosarcoma and leiomyoma from HIV-negative children. EBV clonality of leiomyosarcomas was determined by Southern blot analysis with oligonucleotide probes for EBV terminal-repeat fragments. Tumor specimens were tested by immunoperoxidase staining for infiltration by B lymphocytes and expression of the EBV receptor. Serologic testing for EBV was performed. Results. In situ hybridization showed EBV genomes in all muscle cells of the five leiomyosarcomas and the two leiomyomas from the six HIV-infected patients. Quantitative PCR demonstrated strikingly high levels of EBV in tumor tissue, with as many as 4.3 genome copies per cell. Two colonic leiomyosarcomas obtained from different sites at different times from one patient contained different episomal EBV clones, signifying the presence of distinct monoclonal EBV-related tumors. We found biclonal EBV infection in the leiomyosarcoma of another patient. No EBV was detected in normal muscle or tumor specimens from HIV-negative patients. Immunostaining for the EBV receptor was strongly positive in six of the seven leiomyomas and leiomyosarcomas from the patients with AIDS. Conclusions. EBV can infect smooth-muscle cells, at least in patients with AIDS, and it may contribute to the pathogenesis of leiomyomas and leiomyosarcomas in patients with AIDS. EBV seems to play no part in smooth-muscle tumors in HIV-negative patients.
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