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[Genetic variability of hepatitis C virus in the health area of Elche (Spain). Correlation between core antigen and viral load].

We investigated the prevalence of the various genotypes of hepatitis C virus (HCV) in 281 patients evaluated between March, 2000 and March, 2002 in the health area of Elche. Of these patients, 55 were coinfected with human immunodeficiency virus (HIV). The genotype was related to viral load and the co-existence of HIV infection. Likewise, the relationship between these parameters and the presence of the HCV core antigen was established. The results indicate that genotype 1b was the most prevalent (38.4%) followed by genotype 3a (23.1%). Patients coinfected with HIV presented fewer infections due to group 1 genotypes (p < 0.05).Patients with HIV presented a greater viral load in all the genotypes, with genotype 3 presenting a high viral load. Detection of the HCV core antigen showed a close correlation with viral load determinations. Although not yet sufficiently assessed, determination of the HCV core antigen constitutes a simple technique that could eventually contribute to improving the management of patients with chronic HCV hepatitis.

AIDS-Related Opportunistic Infections↗

PubMed2002

Relationships among brain metabolites, cognitive function, and viral loads in antiretroviral-naïve HIV patients.

This study aims to determine the relationship among cerebral metabolite concentrations (on proton magnetic resonance spectroscopy or (1)H MRS), cognitive function, and clinical variables (CD4, plasma and CSF viral loads, and lipids) in antiretroviral medication-nai;ve HIV patients. We hypothesized that the probable glial markers myo-inositol [MI] and choline compounds [CHO] would correlate with cognitive function, CD4 count, and viral loads, but not with serum lipids. Forty-five antiretroviral-drug-nai;ve HIV patients and 25 control subjects were evaluated. Frontal lobe [MI], [CHO], and total creatine [CR] were elevated, while basal ganglia [CR] were decreased, with increasing dementia severity. As a group, HIV patients showed slowing on fine motor (Grooved Pegboard) and psychomotor function (Trails A & B), and deficits on executive function (Stroop tasks). Lower CD4 counts and elevated plasma viral loads were associated with elevated frontal white matter [MI], which in turn correlated with the Stroop tasks. These findings suggest that systemic factors (resulting from suppressed immune function and higher plasma viral load) may lead to glial proliferation (elevated [MI], [CHO], and [CR]) in the frontal white matter, which in turn may contribute to deficits on executive function in HIV. Studying antiretroviral-nai;ve patients minimized the confounding effects of antiretroviral treatment on the clinical, MRS, and neuropsychological variables, and allowed for a more accurate assessment of the relationships among these measurements. Metabolite concentrations, rather than metabolite ratios, should be measured since [CR], a commonly used reference for metabolite ratios, varies with disease severity in both frontal lobe and basal ganglia.

AIDS Dementia Complex↗

PubMed2002

Viral load response to a pneumococcal conjugate vaccine, polysaccharide vaccine or placebo among HIV-infected patients.

We determined the HIV viral load in 66 adults randomly assigned to receive pneumococcal immunization with one or two doses of protein conjugate vaccine, one dose of polysaccharide vaccine, one dose of each, or placebo. Second doses were given 8 weeks after the first. Mean baseline viral load and CD4 cell count were 3.41 copies/ml (log10) and 457 cells/microl, respectively. We found no change in viral load during 24 weeks of follow-up for any vaccine or combination of vaccines or placebo.

AIDS-Related Opportunistic Infections↗

PubMed2006

The relationship between cytokines and HPV-16, HPV-16 E6, E7, and high-risk HPV viral load in the uterine cervix.

OBJECTIVES: To investigate intralesional cytokine levels in precancerous lesions of the uterine cervix and their relationship with human papillomavirus (HPV) type 16, HPV type 16 E6/E7, and high-risk HPV viral load. METHODS: We performed a prospective study of 67 patients between May 2005 and December 2005. Hybrid Capture II testing was used to identify patients as high-risk HPV DNA-positive or -negative. HPV DNA Chip test was performed for HPV genotyping in all cases found to be HPV DNA-positive. Real-time PCR was used to quantify HPV-16 E6, E7, interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma) transcripts. RESULTS: Among high-risk HPV-infected women, intralesional TNF-alpha, IL-6, IL-10, and IFN-gamma levels had no significant differences according to histologic grade. In multivariate logistic regression analysis, TNF-alpha, IL-6, IL-10, and IFN-gamma were not associated with HPV-16. Increased IFN-gamma was significantly associated with HPV-16 E6- and E7-positive (OR 28.197, 95% CI: 2.658-299.110; OR 19.617, 95% CI: 2.135-180.253, respectively), whereas TNF-alpha, IL-6, and IL-10 were not associated with HPV-16 E6 and E7. In multiple regression analysis, elevated IFN-gamma was significantly associated with increased HPV viral load (P=0.039), whereas TNF-alpha, IL-6, and IL-10 were not significantly associated with HPV viral load. CONCLUSIONS: Among HPV-infected women, IFN-gamma is significantly associated with HPV-16 E6, E7, and high-risk HPV viral load in the uterine cervix. Thus, increased intralesional IFN-gamma may be considered to be a prognostic marker for oncogenic potential of high-risk HPV.

Adult↗

PubMed1997

Early protective effect of CCR-5 delta 32 heterozygosity on HIV-1 disease progression: relationship with viral load. The SEROCO Study Group.

OBJECTIVE: To determine the influence of heterozygosity for the delta 32 mutant CCR-5 allele on HIV-1 disease progression. DESIGN: HIV-1 disease progression and serum viral load were analysed according to the C-C chemokine receptor (CCR)-5 genotype in 412 Caucasian patients (319 men and 93 women) with a known date of seroconversion, who were enrolled in the SEROCO cohort (median follow-up, 74 months). RESULTS: The frequency of heterozygosity for the mutant allele was 17% and did not differ according to sex or risk factor of HIV infection. Heterozygotes were significantly less likely than patients with two functional alleles to have symptomatic primary infection. Their serum viral load was lower during the 6- to 24-month plateau phase after seroconversion. This difference persisted afterwards, although the rate of decline in CD4+ cells was similar. Kaplan-Meier survival curves showed slower progression to clinical AIDS in heterozygotes during the first 7 years following infection (P < 0.02), the two curves tending to join thereafter (overall log-rank test, P = 0.17). However, the interaction term with time did not reach significance in a Cox model. The overall relative risk of progression was 0.67 (95% confidence interval, 0.38-1.18) and was not influenced by adjustment for age at seroconversion or symptomatic primary infection. After adjustment for early viral load the relative risk was 0.83. Pneumocystis carinii pneumonia and toxoplasmosis were less likely to be the first AIDS-defining illness in heterozygotes than in the other patients (0 versus 24.7% of AIDS cases, P = 0.04), despite similar management. CONCLUSION: Deletion of one CCR-5 gene allele appears to protect against HIV-1 disease progression, mainly during the early years of the infection. Heterozygosity for the deletion leads to persistently lower viral load, and also seems to protect against some opportunistic infections.

AIDS-Related Opportunistic Infections↗

PubMed2006

A measurement model of medication adherence to highly active antiretroviral therapy and its relation to viral load in HIV-positive adults.

This study compared a multiple method measurement model of highly active antiretroviral therapy (HAART) adherence with single-method models to determine optimal validity in predicting HIV viral load. Repeated measures of antiretroviral adherence were collected over a 15-month period using three different measurement methods: a self-report questionnaire, an adherence interview item, and electronic medication monitoring. The participants included HIV-positive men and women (n = 323) who were currently prescribed HAART. Single-factor models composed of multiple measurements over time were developed for each adherence method and HIV viral load. The three adherence methods were then combined in a second order factor measurement model. Structural equation modeling was used to test the models. Mean adherence, defined as percent of doses taken, was 92%, 90%, and 57% by self-report, interview, and electronic monitoring, respectively. Reliability of individual measurements of adherence was low. Four or seven assessments were needed to attain acceptable stability, depending on the method. The second-order factor model of adherence fit the data and explained 45% of the variability in HIV viral load. Models including only one method of assessing adherence explained between 20% and 24% of the variability. Models that included both self-report and electronic monitoring optimized predictive validity. Using at least two different methods of adherence measurement, each assessed at multiple times is recommended to derive reliable and valid measurement of medication adherence, which is predictive of biological outcomes such as HIV viral load.

Adolescent↗

PubMed2003

Can drug resistance mutations influence the measurement of plasma HIV-RNA by different viral load techniques?

Guidelines for the use of antiretroviral agents consider that viral load values may differ using the branched DNA (bDNA) and polymerase chain reaction (PCR) methods. Whereas the most commonly used PCR assay (Amplicor v1.5, Roche) targets HIV gag sequences, the bDNA (Quantiplex v3.0, Bayer) is based on the recognition of HIV pol sequences. The possibility that accumulation of drug-resistance mutations at the reverse transcriptase and/or protease genes could influence viral load measurements using bDNA was examined in a case control study. Plasma samples collected from 46 HIV-infected individuals receiving antiretroviral therapy and carrying different number of drug resistance mutations were analyzed. The performance of both bDNA and PCR assays was found to be comparable irrespective of the presence or absence of drug resistance mutations.

Anti-Retroviral Agents↗

PubMed2004

Loss of virus-specific CD4(+) T cells with increases in viral loads in the chronic phase after vaccine-based partial control of primary simian immunodeficiency virus replication in macaques.

Virus-specific cellular immune responses play an important role in the control of immunodeficiency virus replication. However, preclinical trials of vaccines that induce virus-specific cellular immune responses have failed to contain simian immunodeficiency virus (SIV) replication in macaques. A defective provirus DNA vaccine system that efficiently induces virus-specific CD8(+) T-cell responses has previously been developed. The vaccinated macaques showed reduced viral loads, but failed to contain SIVmac239 replication. In this study, macaques that showed partial control of SIV replication were followed up to see if or how they lost this control in the chronic phase. Two of them showed increased viral loads about 4 or 8 months after challenge and finally developed AIDS. Analysis of SIV-specific T-cell levels by detection of SIV-specific gamma interferon (IFN-gamma) production revealed that these two macaques maintained SIV-specific CD8(+) T cells, even after loss of control, but lost SIV-specific CD4(+) T cells when plasma viral loads increased. The remaining macaque kept viral loads at low levels and maintained SIV-specific CD4(+) T cells, as well as CD8(+) T cells, for more than 3 years. Additional analysis using macaques vaccinated with a Gag-expressing Sendai virus vector also found loss of viraemia control, with loss of SIV-specific CD4(+) T cells in the chronic phase of SIV infection. Thus, SIV-specific CD4(+) T cells that were able to produce IFN-gamma in response to SIV antigens were preserved by the vaccine-based partial control of primary SIV replication, but were lost with abrogation of control in the chronic phase.

Animals↗

PubMed1999

Reduction of viral load and immune complex load on CD4+ lymphocytes as a consequence of highly active antiretroviral treatment (HAART) in HIV-infected hemophilia patients.

BACKGROUND AND OBJECTIVES: Human immunodeficiency virus (HIV)-induced immune complex load on circulating CD4+ blood lymphocytes is associated with dysfunction and depletion of CD4+ lymphocytes and with increased monocyte/macrophage function. It was investigated whether HAART reduces both the viral load in plasma and the number of immune complex-coated CD4+ lymphocytes in the blood, and whether CD4+ counts are associated with viral load and/or immune complex load. MATERIALS AND METHODS: Twelve HIV+ hemophilia patients before and after conversion to HAART (group 1); eight HIV+ hemophilia patients without antiretroviral therapy (group 2). HIV-1 RNA copies in plasma using NASBA/Nuclisens kits; CD4+ lymphocytes coated in-vivo with immune complexes using flowcytometry on whole blood samples; in-vitro responses of immune complex-coated T lymphocytes in cell culture assays. RESULTS: After conversion to HAART there was a significant reduction of viral load, CD4+ gp120+, CD4+ IgM+, and CD4+ IgG+ circulating blood lymphocytes and plasma neopterin, paralleled by a significant increase of CD4+ and CD8+ counts. The percentage of immune complex-coated CD4+ lymphocytes of converted patients was significantly associated with CD4+ counts, in-vitro responses to concanavalin A (Con A), pokeweed mitogen (PWM), phytohaemagglutinin (PHA), anti-CD3 and pooled allogeneic stimulator cells, and with plasma neopterin levels. CONCLUSION: HAART reduces viral load and HIV-induced immune complex load on circulating CD4+ blood lymphocytes. The results of this study can be interpreted to suggest that HAART increases CD4+ lymphocyte counts in part by counteracting HIV-induced autoimmune phenomena.

Anti-HIV Agents↗

PubMed2005

Increased levels of HIV RNA detected in samples with viral loads close to the detection limit collected in Plasma Preparation Tubes (PPT).

BACKGROUND: The accurate and reliable quantification of HIV RNA is an essential part of the management of HIV infected individuals, and elucidation of factors that may affect HIV RNA measurements, such as the use of Vacutainer Plasma Preparation Tubes (PPT), is crucial. OBJECTIVES: The objective of this study was to determine if plasma samples with viral loads close to the lower limit of the dynamic range of the assay collected in PPT tubes had increased levels of HIV RNA as compared to samples collected in standard EDTA tubes. STUDY DESIGN: HIV RNA levels were compared in 112 paired plasma samples collected in PPT and standard EDTA tubes. All samples had been frozen prior to testing. RESULTS: Discrepancies between PPT and EDTA tubes did not occur for samples with high viral loads. However, in samples with viral loads close to the lower limit of the dynamic range, levels of HIV RNA detected were higher in a large proportion of PPT as compared to the corresponding EDTA plasma samples. Forty percent of plasma pairs had no detectable HIV RNA in the EDTA aliquot, but had low levels of HIV RNA in the corresponding PPT aliquot. CONCLUSIONS: This prospective study underlines the need for cautious interpretation of small transient viral load changes in samples with values close to the detection limit.

Acquired Immunodeficiency Syndrome↗

PubMed1995

Acute decrease in HIV-1 viral load after initiation of zidovudine therapy: implications for interrupting vertical transmission.

Use of zidovudine (AZT) in pregnant women has recently been reported to reduce the rate of vertical transmission of human immunodeficiency virus type 1 (HIV-1) possibly through a reduction in maternal viral load. To determine how quickly AZT is able to reduce viral load, infectious virus and plasma HIV-1 RNA were sequentially measured in an HIV-1-infected patient at short intervals (hours) after initiation of oral AZT. Peripheral blood samples were collected at baseline, 1, 2, 4, 8, 12, 24, 48 hours, and 1 week after initiation of AZT therapy (500 mg/day) for quantitative plasma HIV-1 RNA levels, p24 antigen levels, and AZT levels. Quantitative HIV-1 peripheral blood mononuclear cell and plasma cultures, CD4 cell counts, and MT-2 cell assays for syncytium-inducing phenotype were performed at baseline, 1, 2 days, and 1 week after initiation of AZT therapy. A significant drop in viral load did not occur until after 24-48 hours. AZT should probably be administered at least 2 days prior to anticipated delivery, if a reduced maternal viral load is responsible for AZT's efficacy in preventing vertical transmission.

CD4 Lymphocyte Count↗

PubMed2005

The Protease Inhibitor Transfer Study (PROTRA 1): abacavir and efavirenz in combination as a substitute for a protease inhibitor in heavily pretreated HIV-1-infected patients with undetectable plasma viral load.

OBJECTIVES: The aim of the study was to evaluate the safety and efficacy of abacavir (ABC) and efavirenz (EFV) instead of a protease inhibitor (PI) in HIV-1-infected subjects treated with two nucleoside reverse transcriptase inhibitors (NRTIs) and one PI with undetectable viral loads (< 50 HIV -1 RNA copies/mL). To be eligible for inclusion, patients had to have a history of viral load < 400 copies/mL for at least 3 months and had to be naive to treatment with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and ABC, but multiple pretreatment and treatment failure were allowed. DESIGN: An open-label, single-centre pilot study of duration 48 weeks was conducted. ABC was added to the original treatment with two NRTIs and one PI at baseline, and at week 6 the PI was replaced by EFV. At each study visit, CD4 cell count, viral load [measured by polymerase chain reaction (PCR)] and clinical chemistry were measured. Fasting blood samples were taken at baseline and at weeks 12, 24, 36 and 48 to measure levels of cholesterol [high-density lipoprotein (HDL)/low-density lipoprotein (LDL)], triglycerides, insulin and C-peptide. Additionally, an oral glucose tolerance test (OGTT) was performed. A bioelectric impedance analysis (BIA) and a single slice abdominal and mid-thigh computed tomography (CT) scan were carried out to assess changes in body composition. RESULTS: Thirty patients were included in the study. Three patients experienced ABC-hypersensitivity and one patient demonstrated virological failure caused by nonadherence. At week 48, all remaining patients had viral loads < 50 copies/mL with stable CD4 counts. The fasting metabolic parameters and abdominal fat distribution remained unchanged. CONCLUSIONS: In heavily pretreated patients, ABC and EFV in combination provide an effective, simplified and well-tolerated alternative to PI treatment.

Adult↗

PubMed2002

Validation of performance of the gen-probe human immunodeficiency virus type 1 viral load assay with genital swabs and breast milk samples.

Human immunodeficiency type 1 (HIV-1) continues to spread at an alarming rate. The virus may be transmitted through blood, genital secretions, and breast milk, and higher levels of systemic virus in the index case, as measured by plasma RNA viral load, have been shown to correlate with increased risk of transmitting HIV-1 both vertically and sexually. Less is known about the correlation between transmission and HIV-1 levels in breast milk or genital secretions, in part because reliable quantitative assays to detect HIV-1 in these fluids are not available. Here we show that the Gen-Probe HIV-1 viral load assay can be used to accurately quantify viral load in expressed breast milk and in cervical and vaginal samples collected on swabs. Virus could be quantified from breast milk and swab samples spiked with known amounts of virus, including HIV-1 subtypes A, C, and D. As few as 10 copies of HIV-1 RNA could be detected above background threshold levels in > or =77% of assays performed with spiked breast milk supernatants and mock swabs. In genital swab samples from HIV-1-infected women, similar levels of HIV-1 RNA were consistently detected in duplicate swabs taken from the same woman on the same clinic visit, suggesting that the RNA values from a single swab sample can be used to measure genital viral load.

Cervix Uteri↗

PubMed2002

Effect of interferon-alpha induction therapy on genotype 2b/3a and low viral load hepatitis C virus infection. A randomized multicentre study.

BACKGROUND: Interferon monotherapy for chronic hepatitis C virus (HCV) infection leads to sustained viral eradication in a minority of patients. However, in selected groups of patients, sustained virological response is observed in as many as 50% of patients. High initial interferon dose (induction therapy) has been reported to increase the initial response rate. We have studied the effect of interferon induction therapy in patients infected with HCV genotype 2b/3a, low viral load and no cirrhosis. METHODS: A total of 71 treatment-naive HCV RNA-positive patients with biopsy-confirmed chronic hepatitis, with genotype 2b or 3a, viral load < or = 3 million copies per ml and no cirrhosis were randomized to receive either standard interferon therapy (3 MIU interferon-alpha-2a thrice weekly) for 26 weeks or 6 MIU interferon-alpha-2a daily for 4 weeks (induction group) followed by the standard dose (3 MIU thrice weekly) for 22 weeks. Those with persistent HCV RNA at 4 weeks stopped treatment. Patients were monitored for HCV RNA during and following treatment, and data were interpreted according to intention-to-treat analysis. RESULTS: Viral clearance occurred more rapidly (after 4 weeks) in the induction group (33/36 = 92%) compared to the standard interferon group (21/35 = 60%) (P = 0.01). Among the initial responders, 23/33 (induction group) compared to 16/21 (standard group) were persistently HCV RNA-negative at the end of treatment. At 52 weeks (6 months' follow-up), 22/36 (61%) (induction group) compared to 10/35 (29%) (standard group) were HCV RNA-negative. Among initial responders, 22/33 (induction group) and 10/21 (standard group) achieved a sustained virological response. Among end-of-treatment responders, 22/24 (induction group) and 10/16 (standard group) were HCV RNA-negative at 6 months' follow-up (P = 0.013). CONCLUSIONS: In patients infected with HCV genotype 2b/3a, low viral load and without cirrhosis, IFN induction therapy increases the initial viral clearance and reduces the risk of relapse in end-of-treatment responders. A sustained virological response was achieved in 61% of the patients receiving IFN induction therapy.

Adolescent↗

PubMed2005

Evaluation of an ultrasensitive p24 antigen assay as a potential alternative to human immunodeficiency virus type 1 RNA viral load assay in resource-limited settings.

An inexpensive enzyme-linked immunosorbent assay method for human immunodeficiency virus type 1 quantitation, ultrasensitive p24 antigen assay (Up24), was compared with RNA viral load assay (VL). Up24 had 100% sensitivity of detection at a viral load of >/=30,000, with sensitivity of 46.4% at a viral load of <30,000 (232 specimens from 65 seropositive subjects). The assay was highly reproducible, with excellent correlation between duplicates and among three laboratories.

Adult↗

PubMed2006

Lymphocyte subsets and viral load in male AIDS patients with major depression: naturalistic study.

This study investigated the relationships between lymphocyte subsets and viral load in AIDS patients with and without major depression. During a 7-year period, a total of 60 male hospitalized AIDS patients were recruited in this study. The diagnosis of major depression in patients was made by the same psychiatrist according to the 4th edition of the Diagnostic and Statistical Manual for Mental Disorders criteria. All patients had data for CD4, CD8 and CD4/CD8, and only 42 patients had viral load data. Of 60 AIDS patients, 32 patients had received highly active antiretroviral therapy and received subsequent assessment of lymphocyte cell counts 1 month later. Using ancova with age adjustment, the authors found that patients with major depression (n = 22) had significantly lower CD8 cell counts than patients without major depression (n = 38). However, CD4 cell counts and CD4/CD8 ratios were not significantly different between these two groups. In addition, there was no significant difference in viral load between patients with major depression (n = 16) and patients without major depression (n = 26). Of 32 patients received highly active antiretroviral therapy, 14 patients with an antidepressant (e.g. fluoxetine 20 mg/day) had significantly decreased CD4 and not CD8 cell counts and significantly reduced CD4/CD8 ratios during a period of 1 month. In conclusion, these results suggest that AIDS patients with major depression had significantly lower CD8 cell counts and might have a more severe inflammation/immunity reaction than patients without major depression.

Acquired Immunodeficiency Syndrome↗

PubMed2006

Parvovirus B19 infection in pregnancy studied by maternal viral load and immune responses.

OBJECTIVES: Facilitate risk assessment of vital complications in fetuses of pregnancies affected by acute parvovirus B19 (B19V) infection. DESIGN: Study of the natural course of maternal B19V infection in four cases, from early pregnancy on. SETTING: University Medical Center in the Netherlands. POPULATION: Pregnant mothers attending obstetric services. METHODS: Serial measurements of the maternal and fetal or neonatal viral load and antibody responses. MAIN OUTCOME MEASURES: Maternal and fetal/neonatal serum B19V viral DNA load and specific IgM and IgG antibodies in maternal serum. RESULTS: Peak viral load levels occurred within 1 week after maternal infection and peak IgM levels were observed 1 week after the peak viral load levels. Approximation of IgG and IgM ratios usually took place 4 weeks after infection. Vertical transmission occurred 1-3 weeks after maternal infection, suggesting that fetal infection occurs during the maternal peak viral load. CONCLUSIONS: Maternal B19V DNA load levels and IgM responses are useful to estimate the risk of parvovirus B19-associated fetal complications. The maternal peak viral load directly precedes the onset of fetal infection and may be used to indicate the stage of intrauterine B19V infection.

Adult↗

PubMed2005

Highly sensitive SIV plasma viral load assay: practical considerations, realistic performance expectations, and application to reverse engineering of vaccines for AIDS.

As new assay methods for quantitative reverse transcription-polymerase chain reaction (RT-PCR), such as real time RT-PCR techniques, approach theoretical limits of per reaction sensitivity, further increments in the sensitivity of measurements of viral load can only be achieved by increasing the amount of input RNA per reaction. We describe a robust, convenient, rapid integrated approach for specimen preparation and real time RT-PCR assay for plasma simian immunodeficiency virus (SIV) RNA viral load that provides a threshold sensitivity of 10 copy Eq/ml, and tolerates less than optimally processed specimens. The method provides accurate quantitation of viral load for the SIV virus isolates in common use for non-human primate studies. We demonstrate the utility of the method in sensitively tracking viral load in an animal showing effective control of viral replication to levels below the threshold for quantitation in conventional assays.

AIDS Vaccines↗