HIV-1 drug resistance genotypic profiles in children with undetectable plasma viremia during antiretroviral therapy

Treatment of HIV-1 infection with highly active antiretroviral therapy has led to sustained viral suppression in the plasma in a large number of children. However, studies have suggested that the integrated provirus in resting CD4+ T lymphocytes could be a source of reactivatable virus and maintain drug-resistant virus. We evaluated the resistance-related mutations in children receiving antiretroviral therapy with prolonged viral suppression. Thirty-two peripheral blood mononuclear cell samples from 16 children with viral loads that had been below detection limits for at least 12 months were obtained at two different time points and the DNAs sequenced. The median CD4 cell count was 1,016 cells/mm³ (347-2,588) and 938 cells/mm³ (440-3,038) at the first and second time points, respectively. The median follow-up time was 15 months (9-27). Six (37.5 percent) and seven (43.75 percent) of the 16 patients showed at least one NRTI-associated mutation in the first and second samples, respectively. Two out of 16 (12.5 percent) had an NNRTI-associated mutation at the first time point and three out of 16 (18.75 percent) at the second. In addition, 14 out of 16 (87.5 percent) had at least one PI-associated mutation at both time points. Despite plasma HIV-1 RNA suppression for at least 12 months, resistance-related mutations from previous antiretroviral failures could still be detected in archival virus. Furthermore, viral evolution occurred at the reverse transcriptase region in spite of viral suppression to levels below 400 copies/mL. Persistence of archival resistant virus may be relevant when considering future treatment options.

Comparison of direct immunofluorescence, conventional cell culture and polymerase chain reaction techniques for detecting respiratory syncytial virus in nasopharyngeal aspirates from infants / Comparação entre imunofluorescência direta, cultura convencional de células e reação em cadeia de polimerase para detectar vírus respiratório sincicial em lavados de nasofaringe de crianças

A total of 316 samples of nasopharyngeal aspirate from infants up to two years of age with acute respiratory-tract illnesses were processed for detection of respiratory syncytial virus (RSV) using three different techniques: viral isolation, direct immunofluorescence, and PCR. Of the samples, 36 (11.4 percent) were positive for RSV, considering the three techniques. PCR was the most sensitive technique, providing positive findings in 35/316 (11.1 percent) of the samples, followed by direct immunofluorescence (25/316, 7.9 percent) and viral isolation (20/315, 6.3 percent) (p < 0.001). A sample was positive by immunofluorescence and negative by PCR, and 11 (31.4 percent) were positive only by RT-PCR. We conclude that RT-PCR is more sensitive than IF and viral isolation to detect RSV in nasopharyngeal aspirate specimens in newborn and infants.

Um total de 316 amostras de lavado de nasofaringe obtidas de crianças em acompanhamento ambulatorial com até dois anos de idade durante episódio de doença aguda do trato respiratório foram processadas para detecção do vírus sincicial respiratório (VSR) utilizando três diferentes técnicas: isolamento viral, imunofluorescência direta e reação em cadeia por polimerase (RT-PCR). Destas amostras, 36 (11,4 por cento) foram positivas para o VSR. A RT-PCR foi a técnica mais sensível, com positividade em 35 (11,1 por cento) das amostras, seguindo-se a imunofluorescência direta (25/316, 7,9 por cento) e o isolamento viral (20/315, 6,3 por cento) (p < 0,001). Uma amostra foi positiva pela imunofluorescência e negativa pela RT-PCR, e 11/36 (31,4 por cento) foram positivas somente pela RT-PCR. Concluímos que a RT-PCR é mais sensível que a imunofluorescência e o isolamento viral para detecção do VRS em amostras de aspirado de nasofaringe de recém-nascidos e lactentes.