Analysis of HIV-1 expression in vivo with in situ hybridization and the polymerase chain reaction.

The objective of the present study was to compare the data of in situ hybridization (ISH), RNA polymerase chain reaction (PCR/RNA) and p24 core antigen (p24 Ag) enzyme immunoassay (EIA) for the detection of HIV-1 expression in peripheral blood mononuclear cells (PBMCs) and in plasma of infected patients at various CDC stages. PBMCs of 24 patients mostly of CDC stage II were obtained from heparinized blood samples, cytocentrifuged and hybridized with a (35S) labelled single-stranded RNA probe specific for gag-pol of LAVBru HIV-1 allowing the detection of genomic and/or messenger RNA. The corresponding plasma samples were used for the determination of p24 Ag by EIA and detection of HIV-1 genomic RNA by RT-PCR using specific primers in the LTR, gag and env regions. Whereas p24 was detected in only six out of 24 patients, both ISH and PCR/RNA enabled the detection of viral RNAs in more than 60% of the patients; cumulation of positive results of ISH and RT-PCR showed that 100% of patients at stage IV and 83% of patients at stages II/III have molecular signs of HIV expression therefore indicating that transcription of the provirus is a highly frequent event, even in the early stages of the disease, and, pleading for undertaking a very early antiviral chemotherapy.