Drug Resistance Mutations During Structured Interruptions of HAART in HIV-1 Infected Children

Abstract

Information concerning structured treatment interruptions (STI) of the Highly Active Antiretroviral Therapy (HAART) and their risk for selecting antiretroviral drug resistance in children is scarce. In this study, we searched for antiretroviral drug resistance mutations at the end of five viral rebounds of two children with HIV and a chronically undetectable viral load (VL) who underwent an STI program. The HAART was interrupted for 4 weeks and then restarted and continued for 12 weeks for three cycles. VL, CD4+/CD8+ lymphocytes, and clinical status were evaluated at the end of each STI and at 6 and 12 weeks after HAART was resumed. Treatment of both the patients based on zidovudine+lamivudine+ritonavir remained identical during the study. The reverse transcriptase (RT)- and protease (PR)-coding regions were sequenced at the end of each viral rebound. One patient experienced progressively lower viral rebounds (269000-31300 at the first and third rebounds, respectively), while the other patient did not experience such a reduction, and the VL of both the patients fell to undetectable levels during therapy. In the five viral rebounds examined, no mutations for resistance to protease inhibitors (PIs) were found and the analysis indicated susceptibility to all PIs currently in clinical use. Although the mutation K103R associated with non-nucleoside reverse transcriptase inhibitor resistance was found in two viral rebounds of one patient, the analysis indicated the absence of resistance to RT inhibitors. As no mutation related to antiretroviral drug resistance was found, our results suggest that the STI program evaluated may have a low risk of selecting antiretroviral drug resistance. Nevertheless, further studies evaluating larger cohorts over longer periods are required before definitive conclusions about the safety of STI of HAART in children may be drawn.

Mutations Related to Antiretroviral Resistance Identified by Ultra-Deep Sequencing in HIV-1 Infected Children under Structured Interruptions of HAART

“…Instead, mutations detected in the protease may have been present before the STI scheme was initiated although it is hard to make correct interpretations of the data without a baseline sequence prior to the STI program. These mutations were also found in the previous study using standard genotyping to assess the effect of the STI [ 6 ]. Additionally, another study also reported the presence of these changes in naïve patients [ 24 ].…”

“…In all four patients, progressively lower viral rebounds were observed with a vigorous development of T CD8+ cells and an initial decrease in the response of T-helper cells, followed by a subsequent increase. In a second study, using a standard genotyping analysis and the HIVdb [ 12 ], the sequences codifying for the protease and reverse transcriptase were analyzed in samples corresponding to the viral rebounds of the STI program, finding no resistance to any of the PI or reverse transcriptase inhibitors commercially available [ 6 ]. Despite the limitations of the number of patients analyzed, the results of that previous work suggested that STI, in the context evaluated, could be safe; however, before suggesting new research in different populations of children, it is necessary to consider the genetic heterogeneity of the viral subpopulations during HIV infection and to assess the presence or absence of mutations associated with antiretroviral resistance even in minority viral populations infecting a patient.…”

“…Two HIV-1 infected children with a viral load (VL) undetectable by HAART (<400 copies/ml), without immunosuppression according to the 1994 CDC classification [ 11 ] and HIV asymptomatic for at least the last twelve months were submitted to a STI program. HAART was interrupted for 4 weeks followed by 12 weeks on treatment, until completion of three interruption/restart cycles (4 weeks off/12 weeks on) as previously described [ 4 , 6 ]. The VL, CD4+ and CD8+ cell counts as well as the clinical status of the patients were evaluated after each interruption period and at 6 and 12 weeks after HAART was restarted.…”

“…However, information available about STI in pediatric patients remains limited and such information in adults is still controversial. The emergence of drug-resistance continues to be a major risk for the STI strategy and it is suspected that low serum levels of antiretroviral drugs during the viral rebounds could be selecting for drug-resistant HIV variants [ 5 , 6 ]. Mutations associated with drug resistance are usually detected through standard sequencing; however, the quasispecies nature of HIV-1 complicates the detection of low-abundance drug-resistant mutations (DRM’s) [ 7 , 8 ].…”

Non Detection of HIV-1 Proviral DNA in PBMCs of the Neonates Born to Iranian HIV-Infected Mothers in PMTCT Program

“…Although in most cases, the antibody-antigen enzymelinked immunosorbent assay test, HIV-1 RNA detection in plasma specimens, and western blot assay are the mainstay of clinical diagnosis (15), in several studies on HIVexposed seronegative individuals (HESN) proviral DNA of HIV-1 has been diagnosed in PBMC samples using polymerase chain reaction (PCR). The seronegative infection has been reported in health care personnel accidentally exposed to infected blood, in people who have frequent blood transfusions, sexual partners of HIV-infected people, and also in children of HIV-1 positive mothers (1,16).…”