Human Immunodeficiency Virus RNA Assay Research Articles

Antiretroviral Therapy Use During Pregnancy and the Risk of Small for Gestational Age Birth in a Medicaid Population.

Several studies have assessed the association between antiretroviral (ARV) therapy use during pregnancy and small for gestational age (SGA), but the evidence remains incompletely elucidated. We linked data from Tennessee Medicaid files and vital records to evaluate pregnancies among human immunodeficiency virus (HIV)-infected women who delivered between 1994 and 2009. Maternal HIV status was defined based on diagnosis codes, ARV prescriptions and laboratory codes for CD4 count or HIV RNA assays. ARV use was identified from pharmacy claims. Risk of SGA (defined as birth weight below the 10th percentile for gestational age) and preterm birth was evaluated using logistic regression models. Four hundred and seventy-seven HIV-infected pregnant women contributing 604 singleton pregnancies were identified; 156 (26%) delivered SGA infants. ARV use during pregnancy was not associated with SGA [adjusted odds ratio: 0.93; 95% confidence interval (CI): 0.56-1.56] or preterm birth (adjusted odds ratio: 0.74; 95% CI: 0.42-1.32). Exposure to a protease inhibitor during the first trimester was associated with a lower risk of SGA (odds ratio: 0.54; 95% CI: 0.29-1.01) compared with non-exposure to a protease inhibitor throughout pregnancy. We observed no evidence of an association between ARV exposure during pregnancy and SGA delivery in this Medicaid cohort of HIV-infected women.

Antiretroviral Intensification and Valproic Acid Lack Sustained Effect on Residual HIV-1 Viremia or Resting CD4+ Cell Infection

BackgroundHuman immunodeficiency virus (HIV) infection that persists despite antiretroviral therapy (ART) is a daunting problem. Given the limited evidence that resting CD4+ T cell infection (RCI) is affected by the histone deacetylase (HDAC) inhibitor valproic acid (VPA), we measured the stability of RCI and residual viremia in patients who added VPA with or without raltegravir (RAL), or enfuvirtide (ENF) with or without VPA, to standard ART.MethodsPatients with plasma HIV RNA<50 c/mL added sustained-release VPA (Depakote ER®) twice daily, RAL 400 mg twice daily, or ENF 90 mcg twice daily. Change in RCI was measured by outgrowth assays. Low-level viremia was quantitated by single-copy plasma HIV RNA assay (SCA).ResultsIn three patients on standard ART a depletion of RCI was observed after 16 weeks of VPA, but this effect waned over up to 96 weeks of further VPA. In two patients ENF added to stable ART had no effect on RCI. Simultaneous intensification with ENF and addition of VPA had no effect on RCI frequency in one patient, and resulted in a 46% decline in a second. No significant depletion of RCI (>50%) was seen in six volunteers after the addition of RAL and VPA. In 4 of the 6 patients this lack of effect might be attributed to intermittent viremia, low VPA levels, or intermittent study therapy adherence. Overall, there was no effect of the addition of RAL or ENF on low-level viremia measured by SCA.ConclusionsThe prospective addition of VPA and RAL, VPA and ENF, or ENF failed to progressively reduce the frequency of RCI, or ablate intermittent and low-level viremia. New approaches such as more potent HDAC inhibition, alone or in combination with intensified ART or other agents that may disrupt proviral latency must be pursued.

Viremia, resuppression, and time to resistance in human immunodeficiency virus (HIV) subtype C during first-line antiretroviral therapy in South Africa.

Episodes of viremia are common in African antiretroviral therapy (ART) programs. We sought to describe viremia, resuppression, and accumulation of resistance during first-line combination ART (cART) in South Africa. Retrospective analysis of a cohort receiving zidovudine, lamivudine, and either efavirenz or nevirapine with human immunodeficiency virus (HIV) RNA monitoring every 6 months. We assessed viremia (HIV RNA >1000 copies/mL after initial HIV RNA response) and resuppression (HIV RNA <400 copies/mL after viremia). Genotypic resistance testing was performed using stored plasma on a subset of patients at first detection of viremia and subsequently among patients with persistent viremia. Between 2002 and 2006, 3727 patients initiated cART (median CD4, 147 cells/mm(3)). Of 1007 patients who developed viremia, 815 had subsequent HIV RNA assays, and 331 (41%) of these resuppressed without regimen switch. At identification of viremia, 45 (66%) of 68 patients had HIV-1 drug resistance, 42 (62%) had nonnucleoside reverse-transcriptase inhibitor (NNRTI)-resistance, 25 (37%) had M184V/I, and 4 (6%) had multi-nucleoside analogue drug mutations. By 12 months of persistent viremia among a subset of 14 patients with resistance testing to 12 months, 11 (78%) had nonnucleoside reverse-transcriptase inhibitor (NNRTI)-resistance, 8 (57%) had M184V/I, and 2 (14%) had multi-nucleoside analogue drug mutations. Resistance was associated with a reduced probability of resuppression; however, 50% of patients with NNRTI resistance resuppressed while receiving an NNRTI. The majority of patients had NNRTI resistance mutations at detection of viremia. However, 41% resuppressed without regimen switch. Our findings support maximizing first-line use while minimizing risk of significant cross-resistance by implementing intensive adherence support and repeat HIV RNA testing 3-6 months after detecting viremia, with regimen switch only if viremia persists.

Coping with the HIV epidemic 1982–2007: 25‐year outcomes of the Hershey Haemophilia Cohort

Coping with the HIV epidemic 1982–2007: 25‐year outcomes of the Hershey Haemophilia Cohort

Comparison of Two Human Immunodeficiency Virus (HIV) RNA Surrogate Assays to the Standard HIV RNA Assay

Human immunodeficiency virus (HIV) RNA testing is the gold standard for monitoring antiretroviral therapy in HIV-infected patients. However, equipment and reagent costs preclude widespread use of the assay in resource-limited settings. The Perkin-Elmer Ultrasensitive p24 assay and the Cavidi Exavir Load assay both offer potentially simpler, less costly technologies for monitoring viral load. These assays were compared to the Roche Amplicor HIV-1 Monitor Test, v1.5, using panels of clinical samples (subtype B) from HIV-positive subjects and HIV-spiked samples (subtypes A, C, D, CRF_01AE, CRF_02AG, and F). The Ultrasensitive p24 assay detected 100% of the spiked samples with virus loads of >250,000 copies/ml and 61% of the clinical samples with virus loads of 219 to 288,850 copies/ml. Detection rates were improved substantially if an external lysis buffer was added to the procedure. The Cavidi assay detected 54 to 100% of spiked samples with virus loads >10,000 copies/ml and 68% of the clinical samples. These detection rates were also greatly improved with a newly implemented version of this kit. Coefficients of variation demonstrate good reproducibility for each of these kits. The results from the Cavidi v1.0, Cavidi v2.0, and Perkin-Elmer, and the Perkin-Elmer Plus external buffers all correlated well with the results from the Roche Monitor Test (r = 0.83 to 0.96, r = 0.84 to 0.99, r = 0.58 to 0.67, and r = 0.59 to 0.95, respectively). Thus, the use of these two assays for monitoring patients, together with less-frequent confirmation testing, offers a feasible alternative to frequent HIV RNA testing in resource-limited settings.

Human Immunodeficiency Virus (HIV) Reverse Transcriptase Activity Correlates with HIV RNA Load: Implications for Resource-Limited Settings

Measurement of human immunodeficiency virus type 1 (HIV-1) plasma RNA levels using Roche AMPLICOR version 1.5 (HIV RNA) is an integral part of monitoring HIV-infected patients in industrialized countries. These assays are currently unaffordable in resource-limited settings. We investigated a reverse transcriptase (RT) assay as a less expensive alternative for measuring viral burden that quantifies RT enzyme activity in clinical plasma samples. A comparison of RT and HIV RNA assays was performed on 29 paired plasma samples from patients living in the United States and 21 paired plasma samples from patients living in Cameroon. RT levels correlated significantly with plasma HIV RNA viral loads in plasma from U.S. patients (r = 0.898; P < 0.001) and Cameroonian patients, a majority of whom were infected with HIV-1 clade type CRF02_AG (r = 0.669; P < 0.01). Among 32 samples with HIV viral load of >2,000 copies/ml, 97% had detectable RT activity. One Cameroon sample had undetectable RNA viral load but detectable RT activity of 3 fg/ml. The RT assay is a simple and less expensive alternative to the HIV RNA assay. Field studies comparing these assays in resource-limited settings are warranted to assess the practicality and usefulness of this assay for monitoring HIV-infected patients on antiretroviral therapy.

Predictors of Residual Viremia in HIV‐Infected Patients Successfully Treated with Efavirenz and Lamivudine plus either Tenofovir or Stavudine

In human immunodeficiency virus (HIV)-infected patients successfully treated with highly active antiretroviral therapy (HAART), a low level of HIV RNA persists in plasma at steady state for years and varies among patients. To understand predictors of residual viremia, we measured HIV RNA levels <50 copies/mL in patients after 1 year of treatment with efavirenz and lamivudine plus either tenofovir disoproxil fumarate (n=55) or stavudine (n=45), by use of an HIV RNA assay with a limit of detection of 2.5 copies/mL. The mean posttreatment HIV RNA levels were 0.58 log(10) copies/mL (3.8 copies/mL) in the tenofovir arm and 0.61 log(10)copies/mL (4.1 copies/mL) in the stavudine arm (P=.24). Forty-seven percent of patients receiving tenofovir, compared with 29% of patients receiving stavudine, had undetectable residual viremia (P=.07). In multivariate analyses, we found that lower baseline HIV RNA levels in plasma, lower HIV DNA levels in peripheral blood mononuclear cells, and inclusion in the tenofovir arm each independently predicted undetectable residual viremia (P<.05). However, a level of residual viremia <50 copies/mL was not associated with CD4 cell count changes or risk of virologic rebound through 72 weeks of follow-up.

Comparison of Two Human Immunodeficiency Virus (HIV) RNA Surrogate Assays to the Standard HIV RNA Assay

Comparison of Two Human Immunodeficiency Virus (HIV) RNA Surrogate Assays to the Standard HIV RNA Assay

Assay validation for left-censored data

In laboratory validation studies, it is often important to assess agreement between two assays, based on different techniques. Oftentimes, both assays have lower limits of detection and thus measurements are left censored. For example, in studies of Human Immunodeficiency Virus (HIV), the branched DNA (bDNA) assay was developed to quantify HIV-1 RNA concentrations in plasma. Validation of newer assays, such as the RT-PCR (reverse transcriptase polymerase chain reaction) involves assessing agreement of measurements obtained using the two techniques. Both bDNA and RT-PCR assays have lower limits of detection and thus new statistical methods are needed for assessing agreement between two left-censored variables. In this paper, we present maximum likelihood and generalized estimating equations approaches to evaluate agreement between two assays that are subject to lower limits of detection. The concordance correlation coefficient is used as an agreement index. The methodology is illustrated using HIV RNA assay data collected as part of a long-term HIV cohort study.

Comparison of an Assay Using Signal Amplification of the Heat-Dissociated p24 Antigen with the Roche Monitor Human Immunodeficiency Virus RNA Assay

Comparison of an Assay Using Signal Amplification of the Heat-Dissociated p24 Antigen with the Roche Monitor Human Immunodeficiency Virus RNA Assay

Resistance against reverse transcriptase inhibitors.

The response to antiretroviral therapy in human immunodeficiency virus (HIV)-infected patients is limited by the emergence of drug resistance. This resistance is a consequence of the high rate of HIV mutation, the high rate of viral replication (especially when potent multidrug therapies are not used or taken reliably), and the selective effect of these drugs, which favors emergence of mutations that can establish clinical drug resistance. The introduction of highly active antiretroviral therapy (HAART), which typically includes at least 2 nucleoside reverse transcriptase inhibitors (RTIs) and a protease inhibitor or a nonnucleoside RTI, for most treatment-naive patients results in a reduction of viral load below the limit of detection determined by currently available HIV RNA assays. It is this marked reduction that results in durable viral suppression, usually only possible by the simultaneous use of 3 or 4 drugs. The RTI components of HAART are crucial for these benefits of combination therapy. Specific amino acid changes are associated with resistance to several RTIs, but new mutation complexes have been observed that can confer broad cross-resistance within this class. Genotypic and phenotypic resistance assays to measure drug resistance are being developed, but refinements in both methodology and our ability to interpret results of these assays are necessary before they are introduced into widespread clinical use.

Early detection of perinatal human immunodeficiency virus (HIV) type 1 infection using HIV RNA amplification and detection. New York City Perinatal HIV Transmission Collaborative Study.

Early diagnosis of perinatally transmitted human immunodeficiency virus type 1 (HIV) infection can guide early interventions. HIV coculture and DNA polymerase chain reaction (DNA-PCR) detect few HIV-infected infants at birth and 90%-100% by age 3 months. Because extracellular HIV RNA may appear soon after infection, a plasma HIV RNA assay was compared with DNA-PCR for early detection of perinatally infected infants. Blood-draw specimens (108) obtained at the same time from 49 HIV-infected infants and 10 specimens from 8 uninfected infants were tested. HIV RNA and DNA-PCR positivity rates were 56% and 33%, respectively, in 36 specimens from 36 infants <28 days of age (binomial test, P = .001). Among 81 specimens obtained after age 14 days, 79 (98%) were positive by HIV RNA testing. No HIV-infected infant specimens were DNA-PCR-positive and HIV RNA-negative. All specimens from 8 uninfected infants were HIV RNA-negative. These results suggest that plasma HIV RNA was detectable earlier and more reliably than HIV DNA in perinatal infection.

Human immunodeficiency virus (HIV) RNA in plasma as the preferred target for therapy in patients with HIV infection: a critique.

The measurement of human immunodeficiency virus (HIV) RNA copies in plasma establishes the prognosis for HIV-infected patients and provides a rapid method of assessing the efficacy of a new antiretroviral agent. However, whether or not periodic measurement of plasma HIV RNA will aid physicians in the long-term treatment of infected patients remains to be proven. Dr. Fessel has reviewed the available literature and suggests that the enthusiasm for this technique of managing HIV infection may be premature. Dr. Fessel emphasizes that solid evidence is needed to prove that prolonged suppression of plasma levels of HIV RNA reflects suppression of viral replication in the lymphoreticular tissue and prevents selection of resistant HIV variants. With such evidence, the usefulness of the plasma HIV RNA assay in the treatment of HIV-infected patients will be more firmly established.