Detection and localisation of HIV-1 DNA and RNA in fixed adult AIDS brain by polymerase chain reaction/in situ hybridisation technique

In the brain of patients with AIDS, HIV-I is localised in a productive form in mononuclear cells. One issue that still needs clarification is whether HIV is localised in cells other than those of mononuclear lineage. Gene amp lification by polymerase chain reaction/in situ hybridisation (PCR-IS) coul d shed light on it. In this study, formalin-fixed, paraffin-embedded brain tissue from ten adult AIDS sufferers was used. Five of them showed evidence of HIV encephalitis (HIVE), five did not show any abnormality. Nested PCR revealed HIV-1 DNA in all HIVE cases and in three of the group without HIVE . HIV-1 DNA and RNA were also detected in situ in seven cases (all seven we re also HIV-1 DNA positive in tube). A higher signal was located in the whi te than in the grey matter. HIV-1 DNA was found in microglia, macrophages, perivascular cells, multinucleated gaint cells (MGC) and in CD68-negative c ells. Some of them were identified as endothelial cells, astrocytes and oli godendrocytes. Reverse transcriptase-PCR-IS was positive in macrophages, MG C, endothelial and glial cells. These results confirm infection of endothel ial cells and other glial cells and give clues about the route of entry of virus into the central nervous system and the pathogenesis of the disease. This study did not give any convincing evidence supporting an infection of neurons by HIV-1.