Evidence for disregulation in the control of Epstein-Barr virus latency in patients with AIDS-related complex.

Patients affected by AIDS-related complex (ARC) show several immunological abnormalities which may lead to a disregulation of immunosurveillance against viral latent infections. In this paper evidence for Epstein-Barr virus (EBV) reactivation in seven out of eight affected by persistent generalized lymphadenopathy is given. These patients showed either elevated levels of circulating EBNA-positive transformed cells or depressed EBV-specific T cell cytotoxicity, as assessed by the regression assay, or both. A direct involvement of EBV in the pathogenesis of ARC is thus suggested. Natural killer cell activity was found decreased, correlating to the evidence of circulating EBV-infected cells and of impaired EBV-specific immune control. These data provide evidence that, when specific immune mechanisms lose control on ubiquitous latent viruses, the risk for reactivation becomes higher. In the case of EBV, direct evidence of this event is provided by the emergence in the peripheral blood of clones of infected cells with unlimited growth potential.