HIGH-LEVELS OF UNINTEGRATED HIV-1 DNA IN BRAIN-TISSUE OF AIDS DEMENTIA PATIENTS

IN the host cell, retro viral DNAs exist in three main forms: unintegrated linear, unintegrated circular, and integrated (the provirus)1. High levels of unintegrated forms of retroviral DNA often correlate with superinfection and accompanying cytopathic effects2-8, as, for example, in the case of feline acquired immunodeficiency7,8. In culture, HIV-1 infection also results in high levels of unintegrated viral DNA although direct correlations with cytopathicity have not been made9,10. The low frequency of HIV-1-infected cells in patients11,12 has made it difficult to determine the structure of the viral DNA in fresh tissue samples from AIDS patients by standard methods such as Southern hybridization. The PCR technique13,14, however, which allows the detection of viral DNA at levels far below that possible by other hybridization methods is, in its conventional form, of limited use for quantitative analysis. To study the amount and form of HIV-1 DNA in primary tissue of AIDS patients we have therefore modified the PCR method. Our results indicate that each of the three species of viral DNA are detectable in blood and brain of AIDS patients and that in autopsy samples from patients with HIV encephalitis there is a considerably higher proportion of unintegrated viral DNA. © 1990 Nature Publishing Group.