GBV-C/HGV and HIV-1 coinfection

An interesting interaction pattern has been found between HIV-1 and GBV-C/HGV, resulting in protection against progression to AIDS. The mechanisms involved in this interaction remain to be clarified. We examined the current knowledge concerning this coinfection and developed hypotheses to explain its effects. A better understanding of this interaction could result in new concepts, which may lead to new strategies to control HIV-1 replication and progression to AIDS.Federal University of São PauloPró-Sangue FoundationUNIFESPSciEL

Profound peripheral T-lymphocyte depletion and activation in disseminated tuberculosis

Three HIV-1-seronegative patients with disseminated tuberculosis presented significant depletion of T-cell counts, in CD4+ and/or CD8+ cells, associated with increased expression of activation marker CD38 on CD8+ T-lymphocytes. This finding raises the question of potential mechanisms involved in the activation or loss of T-cells in disseminated tuberculosis.Federal University of São Paulo Infectious Diseases DivisionUNIFESP, Infectious Diseases DivisionSciEL

Sexual Seroadaptation: Lessons for Prevention and Sex Research from a Cohort of HIV-Positive Men Who Have Sex with Men

BACKGROUND: Surveillance data on sexually transmitted infections (STIs) and behavioral characteristics identified in studies of the risk of seroconversion are often used as to track sexual behaviors that spread HIV. However, such analyses can be confounded by "seroadaptation"--the restriction of unprotected anal intercourse (UAI), especially unprotected insertive UAI, to seroconcordant partnerships. METHODS: We utilized sexual network methodology and repeated-measures statistics to test the hypothesis that seroadaptive strategies reduce the risk of HIV transmission despite numerous partnerships and frequent UAI. PRINCIPAL FINDINGS: In a prospective cohort study of HIV superinfection including 168 HIV-positive men who have sex with men (MSM), we found extensive seroadaptation. UAI was 15.5 times more likely to occur with a positive partner than a negative one (95% confidence interval [CI], 9.1-26.4). Receptive UAI was 4.3 times more likely in seroconcordant partnerships than with negative partners (95% CI, 2.8-6.6), but insertive UAI was 13.6 times more likely with positives (95% CI, 7.2-25.6). Our estimates suggest that seroadaptation reduced HIV transmissions by 98%. CONCLUSION: Potentially effective HIV prevention strategies, such as seroadaptation, have evolved in communities of MSM before they have been recognized in research or discussed in the public health forum. Thus, to be informative, studies of HIV risk must be designed to assess seroadaptive behaviors rather than be limited to individual characteristics, unprotected intercourse, and numbers of partners. STI surveillance is not an effective indicator of trends in HIV incidence where there are strong patterns of seroadaptation

Dynamic Interaction between STLV-1 Proviral Load and T-Cell Response during Chronic Infection and after Immunosuppression in Non-Human Primates

We used mandrills (Mandrillus sphinx) naturally infected with simian T-cell leukemia virus type 1 (STLV-1) as a model for evaluating the influence of natural STLV-1 infection on the dynamics and evolution of the immune system during chronic infection. Furthermore, in order to evaluate the role of the immune system in controlling the infection during latency, we induced immunosuppression in the infected monkeys. We first showed that the STLV-1 proviral load was higher in males than in females and increased significantly with the duration of infection: mandrills infected for 10–6 years had a significantly higher proviral load than those infected for 2–4 years. Curiously, this observation was associated with a clear reduction in CD4+ T-cell number with age. We also found that the percentage of CD4+ T cells co-expressing the activation marker HLA-DR and the mean percentage of CD25+ in CD4+ and CD8+ T cells were significantly higher in infected than in uninfected animals. Furthermore, the STLV-1 proviral load correlated positively with T-cell activation but not with the frequency of T cells secreting interferon γ in response to Tax peptides. Lastly, we showed that, during immunosuppression in infected monkeys, the percentages of CD8+ T cells expressing HLA-DR+ and of CD4+ T cells expressing the proliferation marker Ki67 decreased significantly, although the percentage of CD8+ T cells expressing HLA-DR+ and Ki67 increased significantly by the end of treatment. Interestingly, the proviral load increased significantly after immunosuppression in the monkey with the highest load. Our study demonstrates that mandrills naturally infected with STLV-1 could be a suitable model for studying the relations between host and virus. Further studies are needed to determine whether the different compartments of the immune response during infection induce the long latency by controlling viral replication over time. Such studies would provide important information for the development of immune-based therapeutic strategies

Lactate Dehydrogenase-Elevating Virus Induces Systemic Lymphocyte Activation via TLR7-Dependent IFNα Responses by Plasmacytoid Dendritic Cells

BACKGROUND:Lactate dehydrogenase-elevating virus (LDV) is a natural infectious agent of mice. Like several other viruses, LDV causes widespread and very rapid but transient activation of both B cells and T cells in lymphoid tissues and the blood. The mechanism of this activation has not been fully described and is the focus of the current studies. PRINCIPAL FINDINGS:A known inducer of early lymphocyte activation is IFNalpha, a cytokine strongly induced by LDV infection. Neutralization of IFNalpha in the plasma from infected mice ablated its ability to activate lymphocytes in vitro. Since the primary source of virus-induced IFNalpha in vivo is often plasmacytoid dendritic cells (pDC's), we depleted these cells prior to LDV infection and tested for lymphocyte activation. Depletion of pDC's in vivo eradicated both the LDV-induced IFNalpha response and lymphocyte activation. A primary receptor in pDC's for single stranded RNA viruses such as LDV is the toll-like receptor 7 (TLR7) pattern recognition receptor. Infection of TLR7-knockout mice revealed that both the IFNalpha response and lymphocyte activation were dependent on TLR7 signaling in vivo. Interestingly, virus levels in both TLR7 knockout mice and pDC-depleted mice were indistinguishable from controls indicating that LDV is largely resistant to the systemic IFNalpha response. CONCLUSION:Results indicate that LDV-induced activation of lymphocytes is due to recognition of LDV nucleic acid by TLR7 pattern recognition receptors in pDC's that respond with a lymphocyte-inducing IFNalpha response

A Prospective Controlled Trial of Routine Opt-Out HIV Testing in a Men's Jail

Approximately 10 million Americans enter jails annually. The Centers for Disease Control and Prevention now recommends routine opt-out HIV testing in these settings. The logistics for performing routine opt-out HIV testing within jails, however, remain controversial. The objective of this study was to evaluate the optimal time to routinely HIV test newly incarcerated jail detainees using an opt-out strategy.This prospective, controlled trial of routine opt-out HIV testing was conducted among 298 newly incarcerated male inmates in an urban men's jail in New Haven, Connecticut. 298 sequential entrants to the men's jail over a three week period in March and April 2008 were assigned to be offered routine opt-out HIV testing at one of three points after incarceration: immediate (same day, n = 103), early (next day, n = 98), or delayed (7 days, n = 97). The primary outcome was the proportion of men in each group consenting to testing.Routine opt-out HIV testing was significantly higher for the early (53%: AOR = 2.6; 95% CI = 1.5 to 4.7) and immediate (45%: AOR = 2.3; 95% CI = 1.3 to 4.0) testing groups compared to the delayed (33%) testing group. The immediate and early testing groups, however, did not significantly differ (p = 0.67). In multivariate analyses, factors significantly associated with routine opt-out HIV testing were assignment to the 'early' testing group (p = 0.0003) and low (bond > or = $5,000, immigration or federal charges or pre-sentencing > 30 days) likelihood of early release (p = 0.04). Two subjects received preliminary positive results and one of them was subsequently confirmed HIV seropositive.In this men's jail where attrition was high, routine opt-out HIV testing was not only feasible, but resulted in the highest rates of HIV testing when performed within 24 hours of incarceration.ClinicalTrials.gov NCT00624247

Regulatory T Cell Suppression of Gag-Specific CD8+ T Cell Polyfunctional Response After Therapeutic Vaccination of HIV-1-Infected Patients on ART

We tested the hypothesis that therapeutic vaccination against HIV-1 can increase the frequency and suppressive function of regulatory, CD4+ T cells (Treg), thereby masking enhancement of HIV-1-specific CD8+ T cell response. HIV-1-infected subjects on antiretroviral therapy (N = 17) enrolled in a phase I therapeutic vaccine trial received 2 doses of autologous dendritic cells (DC) loaded with HIV-1 peptides. The frequency of CD4+CD25hiFOXP3+ Treg in blood was determined prior to and after vaccination in subjects and normal controls. Polyfunctional CD8+ T cell responses were determined pre- and post-vaccine (N = 7) for 5 immune mediators after in vitro stimulation with Gag peptide, staphylococcal enterotoxin B (SEB), or medium alone. Total vaccine response (post-vaccine–pre-vaccine) was compared in the Treg(+) and Treg-depleted (Treg-) sets. After vaccination, 12/17 subjects showed a trend of increased Treg frequency (P = 0.06) from 0.74% to 1.2%. The increased frequency did not correlate with CD8+ T cell vaccine response by enzyme linked immunosorbent assay for interferon γ production. Although there was no significant change in CD8+ T cell polyfunctional response after vaccination, Treg depletion increased the polyfunctionality of the total vaccine response (P = 0.029), with a >2-fold increase in the percentage of CD8+ T cells producing multiple immune mediators. In contrast, depletion of Treg did not enhance polyfunctional T cell response to SEB, implying specificity of suppression to HIV-1 Gag. Therapeutic immunization with a DC-based vaccine against HIV-1 caused a modest increase in Treg frequency and a significant increase in HIV-1-specific, Treg suppressive function. The Treg suppressive effect masked an increase in the vaccine-induced anti-HIV-1-specific polyfunctional response. The role of Treg should be considered in immunotherapeutic trials of HIV-1 infection

Prevalence, Incidence Density, and Genotype Distribution of GB Virus C Infection in a Cohort of Recently HIV-1-Infected Subjects in São Paulo, Brazil

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 São 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 São 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.Ministry of HealthSão Paulo City Health DepartmentFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ São Paulo, Div Clin Immunol & Allergy, São Paulo, BrazilUniversidade Federal de São Paulo, Div Infect Dis, São Paulo, BrazilSão Paulo Blood Bank, São Paulo, BrazilUniv São Paulo, Inst Trop Med, São Paulo, BrazilUniversidade Federal de São Paulo, Div Infect Dis, São Paulo, BrazilMinistry of Health: 914/BRA/3014-UNESCO/KallasSão Paulo City Health Department: 2004-0.168.922-7/KallasFAPESP: 04/15856-9/Diaz, Sabino KallasFAPESP: 05/01072-9/LeviWeb of Scienc