Evaluation of GBV-C / HVG viremia in HIV-infected women.

The present study aimed at standardizing a real-time quantitative polymerase chain reaction assay to evaluate the presence of GBV-C/HGV RNA. A "TaqMan" assay using primers and probe derived from the 5¢ NCR region was developed and validated. Two hundred and fifty-three plasma samples from HIV-infected women were tested for GBV-C viremia and antibody against the envelope protein 2. GBV-C RNA was detected in 22.5% of the patients whereas the antibody was identified in 25.3% of the cohort. Detection of viral RNA and of antibodies was mutually exclusive. Viral loads showed a mean of 1,777 arbitrary units / mL, being 1.1 and 13,625 arbitrary units / mL respectively the lowest and highest values measured. We conclude that the real-time quantitative polymerase chain reaction method developed is appropriate for the investigation of GBV-C RNA since it was shown to be highly specific and sensitive, as well as requiring few steps, preventing contamination and providing additional information as to the relative viremia of carriers, a parameter that must be included in studies evaluating the co-factors influencing the clinical outcome of HIV/AIDS.

Evaluation of GBV-C / HVG viremia in HIV-infected women / Avaliação da viremia por GBV-C/HGV em mulheres infectadas pelo HIV

The present study aimed at standardizing a real-time quantitative polymerase chain reaction assay to evaluate the presence of GBV-C/HGV RNA. A "TaqMan" assay using primers and probe derived from the 5¢ NCR region was developed and validated. Two hundred and fifty-three plasma samples from HIV-infected women were tested for GBV-C viremia and antibody against the envelope protein 2. GBV-C RNA was detected in 22.5 percent of the patients whereas the antibody was identified in 25.3 percent of the cohort. Detection of viral RNA and of antibodies was mutually exclusive. Viral loads showed a mean of 1,777 arbitrary units / mL, being 1.1 and 13,625 arbitrary units / mL respectively the lowest and highest values measured. We conclude that the real-time quantitative polymerase chain reaction method developed is appropriate for the investigation of GBV-C RNA since it was shown to be highly specific and sensitive, as well as requiring few steps, preventing contamination and providing additional information as to the relative viremia of carriers, a parameter that must be included in studies evaluating the co-factors influencing the clinical outcome of HIV/AIDS.

Este estudo teve como objetivo o desenvolvimento de método de PCR em Tempo Real para a determinação da viremia do vírus GBV-C. Ensaio baseado em primers e sonda "TaqMan" derivados da região 5' não-codificante deste vírus foi padronizado, validado e aplicado em uma série de 253 amostras de plasma de pacientes HIV+. Além do PCR em tempo real, as amostras foram submetidas a um ensaio imunoenzimático anti-E2 e a um nested-PCR. Das 253 amostras testadas, 64 foram positivas para o anticorpo anti-E2 (25,3 por cento), enquanto 57 amostras foram concordantemente RNA positivas pelo nested-PCR e PCR em tempo real (22,5 por cento), perfazendo um índice total de exposição de 48 por cento (25.3 + 22.5). A carga viral teve média de 1.777 UA/mL (13.625 - 1.1UA/mL). Foi obtida metodologia simples, rápida e de boa sensibilidade e especificidade, permitindo a quantificação do RNA do vírus GBV-C com reprodutibilidade. A metodologia permite a análise simultânea de grande número de amostras, sendo apropriada para estudos clínicos. A prevalência de exposição a este agente na população feminina HIV+ estudada é alta, provavelmente decorrente da via sexual comum de transmissão dos agentes.