987 resultados para Viral load


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Systemic immune activation, a major determinant of HIV disease progression, is the result of a complex interplay between viral replication, dysregulation of the immune system, and microbial translocation due to gut mucosal damage. While human genetic variants influencing HIV viral load have been identified, it is unknown to what extent the host genetic background contributes to inter-individual differences in other determinants of HIV pathogenesis like gut damage and microbial translocation. Using samples and data from 717 untreated participants in the Swiss HIV Cohort Study and a genome-wide association study design, we searched for human genetic determinants of plasma levels of intestinal fatty-acid binding protein (I-FABP/FABP2), a marker of gut damage, and of soluble sCD14 (sCD14), a marker of LPS bioactivity and microbial translocation. We also assessed the correlations between HIV viral load, sCD14 and I-FABP. While we found no genome-wide significant determinant of the tested plasma markers, we observed strong associations between sCD14 and both HIV viral load and I-FABP, shedding new light on the relationships between processes that drive progression of untreated HIV infection.

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OBJECTIVE To determine the effect of nonadherence to antiretroviral therapy (ART) on virologic failure and mortality in naive individuals starting ART. DESIGN Prospective observational cohort study. METHODS Eligible individuals enrolled in the Swiss HIV Cohort Study, started ART between 2003 and 2012, and provided adherence data on at least one biannual clinical visit. Adherence was defined as missed doses (none, one, two, or more than two) and percentage adherence (>95, 90-95, and <90) in the previous 4 weeks. Inverse probability weighting of marginal structural models was used to estimate the effect of nonadherence on viral failure (HIV-1 viral load >500 copies/ml) and mortality. RESULTS Of 3150 individuals followed for a median 4.7 years, 480 (15.2%) experienced viral failure and 104 (3.3%) died, 1155 (36.6%) reported missing one dose, 414 (13.1%) two doses and, 333 (10.6%) more than two doses of ART. The risk of viral failure increased with each missed dose (one dose: hazard ratio [HR] 1.15, 95% confidence interval 0.79-1.67; two doses: 2.15, 1.31-3.53; more than two doses: 5.21, 2.96-9.18). The risk of death increased with more than two missed doses (HR 4.87, 2.21-10.73). Missing one to two doses of ART increased the risk of viral failure in those starting once-daily (HR 1.67, 1.11-2.50) compared with those starting twice-daily regimens (HR 0.99, 0.64-1.54, interaction P = 0.09). Consistent results were found for percentage adherence. CONCLUSION Self-report of two or more missed doses of ART is associated with an increased risk of both viral failure and death. A simple adherence question helps identify patients at risk for negative clinical outcomes and offers opportunities for intervention.

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The risk of disease associated with persistent virus infections such as HIV-I, hepatitis B and C, and human T-lymphotropic virus-I (HTLV-I) is strongly determined by the virus load. However, it is not known whether a persistent class I HLA-restricted antiviral cytotoxic T lymphocyte (CTL) response reduces viral load and is therefore beneficial or causes tissue damage and contributes to disease pathogenesis. HTLV-I-associated myelopathy (HAM/TSP) patients have a high virus load compared with asymptomatic HTLV-I carriers. We hypothesized that HLA alleles control HTLV-I provirus load and thus influence susceptibility to HAM/TSP. Here we show that, after infection with HTLV-I, the class I allele HLA-A*02 halves the odds of HAM/TSP (P < 0.0001), preventing 28% of potential cases of HAM/TSP. Furthermore, HLA-A*02+ healthy HTLV-I carriers have a proviral load one-third that (P = 0.014) of HLA-A*02− HTLV-I carriers. An association of HLA-DRB1*0101 with disease susceptibility also was identified, which doubled the odds of HAM/TSP in the absence of the protective effect of HLA-A*02. These data have implications for other persistent virus infections in which virus load is associated with prognosis and imply that an efficient antiviral CTL response can reduce virus load and so prevent disease in persistent virus infections.

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Identifying the immunologic and virologic consequences of discontinuing antiretroviral therapy in HIV-infected patients is of major importance in developing long-term treatment strategies for patients with HIV-1 infection. We designed a trial to characterize these parameters after interruption of highly active antiretroviral therapy (HAART) in patients who had maintained prolonged viral suppression on antiretroviral drugs. Eighteen patients with CD4+ T cell counts ≥ 350 cells/μl and viral load below the limits of detection for ≥1 year while on HAART were enrolled prospectively in a trial in which HAART was discontinued. Twelve of these patients had received prior IL-2 therapy and had low frequencies of resting, latently infected CD4 cells. Viral load relapse to >50 copies/ml occurred in all 18 patients independent of prior IL-2 treatment, beginning most commonly during weeks 2–3 after cessation of HAART. The mean relapse rate constant was 0.45 (0.20 log10 copies) day−1, which was very similar to the mean viral clearance rate constant after drug resumption of 0.35 (0.15 log10 copies) day−1 (P = 0.28). One patient experienced a relapse delay to week 7. All patients except one experienced a relapse burden to >5,000 RNA copies/ml. Ex vivo labeling with BrdUrd showed that CD4 and CD8 cell turnover increased after withdrawal of HAART and correlated with viral load whereas lymphocyte turnover decreased after reinitiation of drug treatment. Virologic relapse occurs rapidly in patients who discontinue suppressive drug therapy, even in patients with a markedly diminished pool of resting, latently infected CD4+ T cells.

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This study was designed to assess the effect of sequence mismatches between primers and their targets on viral quantitative PCR. Numerous primers were constructed incorporating various mismatches with a target sequence on the BKV T antigen gene. When using these primers in standard Taqman two-step cycling conditions, as few as two mismatches in a single primer increased cycle threshold values and significantly influenced the calculation of viral load. (C) 2005 Elsevier B.V. All rights reserved.

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Substantial complexity has been introduced into treatment regimens for patients with human immunodeficiency virus (HIV) infection. Many drug-related problems (DRPs) are detected in these patients, such as low adherence, therapeutic inefficacy, and safety issues. We evaluated the impact of pharmacist interventions on CD4+ T-lymphocyte count, HIV viral load, and DRPs in patients with HIV infection. In this 18-month prospective controlled study, 90 outpatients were selected by convenience sampling from the Hospital Dia-University of Campinas Teaching Hospital (Brazil). Forty-five patients comprised the pharmacist intervention group and 45 the control group; all patients had HIV infection with or without acquired immunodeficiency syndrome. Pharmaceutical appointments were conducted based on the Pharmacotherapy Workup method, although DRPs and pharmacist intervention classifications were modified for applicability to institutional service limitations and research requirements. Pharmacist interventions were performed immediately after detection of DRPs. The main outcome measures were DRPs, CD4+ T-lymphocyte count, and HIV viral load. After pharmacist intervention, DRPs decreased from 5.2 (95% confidence interval [CI] =4.1-6.2) to 4.2 (95% CI =3.3-5.1) per patient (P=0.043). A total of 122 pharmacist interventions were proposed, with an average of 2.7 interventions per patient. All the pharmacist interventions were accepted by physicians, and among patients, the interventions were well accepted during the appointments, but compliance with the interventions was not measured. A statistically significant increase in CD4+ T-lymphocyte count in the intervention group was found (260.7 cells/mm(3) [95% CI =175.8-345.6] to 312.0 cells/mm(3) [95% CI =23.5-40.6], P=0.015), which was not observed in the control group. There was no statistical difference between the groups regarding HIV viral load. This study suggests that pharmacist interventions in patients with HIV infection can cause an increase in CD4+ T-lymphocyte counts and a decrease in DRPs, demonstrating the importance of an optimal pharmaceutical care plan.

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In acquired immunodeficiency syndrome (AIDS) studies it is quite common to observe viral load measurements collected irregularly over time. Moreover, these measurements can be subjected to some upper and/or lower detection limits depending on the quantification assays. A complication arises when these continuous repeated measures have a heavy-tailed behavior. For such data structures, we propose a robust structure for a censored linear model based on the multivariate Student's t-distribution. To compensate for the autocorrelation existing among irregularly observed measures, a damped exponential correlation structure is employed. An efficient expectation maximization type algorithm is developed for computing the maximum likelihood estimates, obtaining as a by-product the standard errors of the fixed effects and the log-likelihood function. The proposed algorithm uses closed-form expressions at the E-step that rely on formulas for the mean and variance of a truncated multivariate Student's t-distribution. The methodology is illustrated through an application to an Human Immunodeficiency Virus-AIDS (HIV-AIDS) study and several simulation studies.

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Background: The results of previous studies elsewhere have indicated that GB virus C (GBV-C) infection is frequent in patients infected with the human immunodeficiency virus type 1 (HIV-1) due to similar transmission routes of both viruses. The aim of this study was to determine the prevalence, incidence density and genotypic characteristics of GBV-C in this population. Methodology/Principal Findings: The study population included 233 patients from a cohort primarily comprised of homosexual men recently infected with HIV-1 in Sao Paulo, Brazil. The presence of GBV-C RNA was determined in plasma samples by reverse transcriptase-nested polymerase chain reaction and quantified by real-time PCR. GBV-C genotypes were determined by direct sequencing. HIV viral load, CD4+ T lymphocyte and CD8+ T lymphocyte count were also tested in all patients. The overall prevalence of GBV-C infection was 0.23 (95% CI: 0.18 to 0.29) in the study group. There was no significant difference between patients with and without GBV-C infection and Glycoprotein E2 antibody presence regarding age, sex, HIV-1 viral load, CD4+ and CD8+ T cell counts and treatment with antiretroviral drugs. An inverse correlation was observed between GBV-C and HIV-1 loads at enrollment and after one year. Also, a positive but not significant correlation was observed between GBV-C load and CD4+ T lymphocyte. Phylogenetic analysis of the GBV-C isolates revealed the presence of genotype 1 and genotype 2, these sub classified into subtype 2a and 2b. Conclusion/Significance: GBV-C infection is common in recently HIV -1 infected patients in Sao Paulo, Brazil and the predominant genotype is 2b. This study provides the first report of the GBV-C prevalence at the time of diagnosis of HIV-1 and the incidence density of GBV-C infection in one year.

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Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the etiologic agent of all forms of Kaposi's sarcoma, primary effusion lymphoma and the plasmablastic cell variant of multicentric Castleman disease. In endemic areas of sub-Saharan Africa, blood transfusions have been associated with a substantial risk of HHV-8 transmission. By contrast, several studies among healthy blood donors from North America have failed to detect HHV-8 DNA in samples of seropositive individuals. In this study, using a real-time PCR assay, we investigated the presence of HHV-8 DNA in whole-blood samples of 803 HHV-8 blood donors from three Brazilian states (Sao Paulo, Amazon, Bahia) who tested positive for HHV-8 antibodies, in a previous multicenter study. HHV-8 DNA was not detected in any sample. Our findings do not support the introduction of routine HHV-8 screening among healthy blood donors in Brazil. (WC = 140).

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HIV-infected patients are at risk for vaccine-preventable infections. The Brazilian National Immunization Program provided recommendations for this population. However, the vaccine coverage reached by this program is unknown. This study aimed at evaluating the vaccine coverage of HIV-infected adults followed at Hospital das Clinicas, University of Sao Paulo School of Medicine. Data were collected on age, gender, mode of HIV transmission, Centers for Disease Classification 1993 classification (CDC/93), antiretrovirals, CD4 count, HIV viral load, and immunization charts, from April 2003 to August 2004. We interviewed 144 randomly selected patients, 74% male; mean age, 39.95 years; CDC classification: A, 40.6%; B, 19.6%; and C, 39.9%. Most of patients were undergoing highly active antiretroviral therapy (HAART; 86.8%). Mean CD4 count 442.6 cells/mm(3). Viral load less than 400 copies per milliliter in 59.4% of patients. Only 36.1% of patients were adequately immunized for diphtheria/tetanus, 54.9% for pneumococcus, 24.3% for flu, and 76.9% for hepatitis B. In relation to live attenuated vaccines, 5 patients received measles, mumps, and rubella vaccine and 7 patients yellow fever vaccine. Two patients were vaccinated against yellow fever despite CD4 less than 200 cell/mm(3). We verified poor vaccine coverage in HIV-infected patients. Vaccination campaigns and incorporation of vaccine rooms in sexually transmitted disease (STD)/AIDS clinics could improve this situation.

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Background: HBV-HIV co-infection is associated with an increased liver-related morbidity and mortality. However, little is known about the natural history of chronic hepatitis B in HIV-infected individuals under highly active antiretroviral therapy (HAART) receiving at least one of the two drugs that also affect HBV (TDF and LAM). Information about HBeAg status and HBV viremia in HIV/HBV co-infected patients is scarce. The objective of this study was to search for clinical and virological variables associated with HBeAg status and HBV viremia in patients of an HIV/HBV co-infected cohort. Methods: A retrospective cross-sectional study was performed, of HBsAg-positive HIV-infected patients in treatment between 1994 and 2007 in two AIDS outpatient clinics located in the Sao Paulo metropolitan area, Brazil. The baseline data were age, sex, CD4 T+ cell count, ALT level, HIV and HBV viral load, HBV genotype, and duration of antiretroviral use. The variables associated to HBeAg status and HBV viremia were assessed using logistic regression. Results: A total of 86 HBsAg patients were included in the study. Of these, 48 (56%) were using combination therapy that included lamivudine (LAM) and tenofovir (TDF), 31 (36%) were using LAM monotherapy, and 7 patients had no previous use of either one. Duration of use of TDF and LAM varied from 4 to 21 and 7 to 144 months, respectively. A total of 42 (48. 9%) patients were HBeAg positive and 44 (51. 1%) were HBeAg negative. The multivariate analysis revealed that the use of TDF for longer than 12 months was associated with undetectable HBV DNA viral load (serum HBV DNA level < 60 UI/ml) (p = 0. 047). HBeAg positivity was associated with HBV DNA > 60 UI/ml (p = 0. 001) and ALT levels above normality (p = 0. 038). Conclusion: Prolonged use of TDF containing HAART is associated with undetectable HBV DNA viral load. HBeAg positivity is associated with HBV viremia and increased ALT levels.

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The aim of this study was to investigate HIV-1 molecular diversity and the epidemiological profile of HIV-1-infected patients from Ribeirao Preto, Brazil. A nested PCR followed by sequencing of a 302-base pair fragment of the env gene (C2-V3 region) was performed in samples from HIV-1-positive patients. A total of 45 sequences were aligned with final manual adjustments. The phylogenetic analyses showed a higher prevalence of HIV-1 subtype B in the studied population (97.8%) with only one sample yielding an F1 subtype. The viral genotyping prediction showed that CCR5 tropism was the most prevalent in the studied cohort. Geno2pheno analysis showed that R5 and CXCR4 prediction were 69% and 31%, respectively. There was no statistical significance, either in viral load or in CD4(+) T cell count when R5 and X4 prediction groups were compared. Moreover, the GPGR tetramer was the most common V3 loop core motif identified in the HIV-1 strains studied (34.1%) followed by GWGR, identified in 18.1% of the samples. The high level of B subtype in this Brazilian population reinforces the nature of the HIV epidemic in Brazil, and corroborates previous data obtained in the Brazilian HIV-infected population.

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Esophageal ulcer (EU) represents an important comorbidity in AIDS. We evaluated the prevalence of EU, the accuracy of the endoscopic and histologic methods used to investigate viral EU in HIV-positive Brazilian patients and the numerical relevance of tissue sampling. A total of 399 HIV-positive patients underwent upper gastrointestinal (UGI) endoscopy. HIV-positive patients with EU determined by UGI endoscopy followed by biopsies were analyzed by the hematoxylin-eosin (HE) and immunohistochemical (IH) methods. EU was detected in 41 patients (mean age, 39.2 years; 23 males), with a prevalence of 10.27%. The median CD4 count was 49 cells/mm(3) (range, 1-361 cells/mm(3)) and the viral load was 58,869 copies per milliliter (range, 50-77,3290 copies per milliliter). UGI endoscopy detected 29 of 41 EU suggestive of cytomegalovirus (CMV) infection and 7 of 41 indicating herpes simplex virus (HSV) infection. HE histology confirmed 4 of 29 ulcers induced by CMV, 2 of 7 induced by HSV, and 1 of 7 induced by HSV plus CMV. IH for CMV and HSV confirmed the HE findings and detected one additional CMV-induced case. UGI endoscopy showed 100% sensitivity and 15% specificity for the diagnosis of EU due to CMV or HSV compared to HE and IH. HE proved to be an adequate method for etiologic evaluation, with 87% sensitivity and 100% specificity compared to IH. The number of samples did not influence the etiologic evaluation. The data support the importance of IH as a complementary method for HE in the diagnosis of EU of viral etiology.

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Objective: To determine whether coinfection with sexually transmitted diseases (STD) increases HIV shedding in genital-tract secretions, and whether STD treatment reduces this shedding. Design: Systematic review and data synthesis of cross-sectional and cohort studies meeting. predefined quality criteria. Main Outcome Measures: Proportion of patients with and without a STD who had detectable HIV in genital secretions, HIV toad in genital secretions, or change following STD treatment. Results: Of 48 identified studies, three cross-sectional and three cohort studies were included. HIV was detected significantly more frequently in participants infected with Neisseria gonorrhoeae (125 of 309 participants, 41%) than in those without N gonorrhoeae infection (311 of 988 participants, 32%; P = 0.004). HIV was not significantly more frequently detected in persons infected with Chlamydia trachomatis (28 of 67 participants, 42%) than in those without C trachomatis infection (375 of 1149 participants, 33%; P = 0.13). Median HIV load reported in only one study was greater in men with urethritis (12.4 x 10(4) versus 1.51 x 10(4) copies/ml; P = 0.04). In the only cohort study in which this could be fully assessed, treatment of women with any STD reduced the proportion of those with detectable HIV from 39% to 29% (P = 0.05), whereas this proportion remained stable among controls (15-17%), A second cohort study reported fully on HIV load; among men with urethritis, viral load fell from 12.4 to 4.12 x 10(4) copies/ml 2 weeks posttreatment, whereas viral load remained stable in those without urethritis. Conclusion: Few high-quality studies were found. HIV is detected moderately more frequently in genital secretions of men and women with a STD, and HIV load is substantially increased among men with urethritis, Successful STD treatment reduces both of these parameters, but not to control levels. More high-quality studies are needed to explore this important relationship further.

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Background & Aims: EPIC-3 is a prospective, international study that has demonstrated the efficacy of PEG-IFN alfa-2b plus weight-based ribavirin in patients with chronic hepatitis C and significant fibrosis who previously failed any interferon-alfa/ribavirin therapy. The aim of the present study was to assess FibroTest (FT), a validated non-invasive marker of fibrosis in treatment-naive patients, as a possible alternative to biopsy as the baseline predictor of subsequent early virologic (EVR) and sustained virologic response (SVR) in previously treated patients. Methods: Of 2312 patients enrolled, 1459 had an available baseline FT, biopsy, and complete data. Uni- (UV) and multi-variable (MV) analyses were performed using FT and biopsy. Results: Baseline characteristics were similar as in the overall population; METAVIR stage: 28% F2, 29% F3, and 43% F4, previous relapsers 29%, previous PEG-IFN regimen 41%, high baseline viral load (BVL) 64%. 506 patients (35%) had undetectable HCV-RNA at TW12 (TW12neg), with 58% achieving SVR. The accuracy of FT was similar to that in naive patients: AUROC curve for the diagnosis of F4 vs F2 = 0.80 (p<0.00001). Five baseline factors were associated (p<0.001) with SVR in UV and MV analyses (odds ratio: UV/MV): fibrosis stage estimated using FT (4.5/5.9) or biopsy (1.5/1.6), genotype 2/3 (4.5/5.1), BVL (1.5/1.3), prior relapse (1.6/1.6), previous treatment with non-PEG-IFN (2.6/2.0). These same factors were associated (p <= 0.001) with EVR. Among patients TW12neg, two independent factors remained highly predictive of SVR by MV analysis (p <= 0.001): genotype 2/3 (odds ratio = 2.9), fibrosis estimated with FT (4.3) or by biopsy (1.5). Conclusions: FibroTest at baseline is a possible non-invasive alternative to biopsy for the prediction of EVR at 12 weeks and SVR, in patients with previous failures and advanced fibrosis, retreated with PEG-IFN alfa-2b and ribavirin. (C) 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.