Endotoxemia is associated with altered innate and adaptive immune responses in untreated HIV-1 infected individuals.
ABSTRACT: Microbial translocation may contribute to the immunopathogenesis in HIV infection. We investigated if microbial translocation and inflammation were associated with innate and adaptive immune responses in adults with HIV.This was an observational cohort study. Sera from HIV-infected and HIV-uninfected individuals were analyzed for microbial translocation (soluble CD14, lipopolysaccharides [LPS], endotoxin core antibody, and anti-?-galactosyl antibodies) and inflammatory markers (high sensitivity C-reactive protein, IL-6, IL-1 receptor antagonist, soluble tumor necrosis factor receptor II, and IL-10) with enzyme-linked immunosorbent assays. Peripheral blood mononuclear cells (PBMC) from HIV-infected persons and healthy controls (primed with single-stranded HIV-1-derived RNA) were stimulated with LPS, and cytokine production was measured. Finally, HIV-infected patients were immunized with Prevnar 7vPnC±CpG 7909 followed by Pneumo Novum PPV-23. Effects of microbial translocation and inflammation on immunization were analyzed in a predictive regression model. We included 96 HIV-infected individuals, 76 on highly active antiretroviral therapy (HAART), 20 HAART-naive, and 50 healthy controls. Microbial translocation and inflammatory markers were higher among HIV-infected persons than controls. Cytokine levels following LPS stimulation were increased in PBMCs from HAART-naive compared to HAART-treated HIV-infected persons. Further, RNA-priming of PBMCs from controls acted synergistically with LPS to augment cytokine responses. Finally, high serum LPS levels predicted poor vaccine responses among HAART-naive, but not among HAART-treated HIV-infected individuals.LPS acts synergistically with HIV RNA to stimulate innate immune responses in vitro and increasing serum LPS levels seem to predict poor antibody responses after vaccination among HAART-naive HIV-infected persons. Thus, our results suggest that microbial translocation may be associated with innate and adaptive immune dysfunction in untreated HIV infection.
Project description:Persons infected with HIV are particularly vulnerable to a variety of oral microbial diseases. Although various study designs and detection approaches have been used to compare the oral microbiota of HIV-negative and HIV-positive persons, both with and without highly active antiretroviral therapy (HAART), methods have varied, and results have not been consistent or conclusive. The purpose of the present study was to compare the oral bacterial community composition in HIV-positive persons under HAART to an HIV-negative group using 16S rRNA gene sequence analysis. Extensive clinical data was collected, and efforts were made to balance the groups on clinical variables to minimize confounding. Multivariate analysis was used to assess the independent contribution of HIV status. Eighty-nine HIV-negative participants and 252 HIV-positive participants under HAART were sampled. The independent effect of HIV under HAART on the oral microbiome was statistically significant, but smaller than the effect of gingivitis, periodontal disease, smoking, caries, and other clinical variables. In conclusion, a multivariate comparison of a large sample of persons with HIV under HAART to an HIV-negative control group showed a complex set of clinical features that influenced oral bacterial community composition, including the presence of HIV under HAART.
Project description:Liver disease is a leading cause of mortality among HIV-infected persons in the highly active anti-retroviral therapy (HAART) era. Hepatitis C Virus (HCV) co-infection is prevalent in, and worsened by HIV; consequently many co-infected persons require liver transplantation (LT). Despite the need, post-LT outcomes are poor in co-infection. We examined predictors of outcomes post-LT. Immunologic biomarkers of immune activation, microbial translocation, and Th1/Th2 skewing were measured pre-LT in participants enrolled in a cohort of HIV infected persons requiring solid organ transplant (HIVTR). Predictive biomarkers were analyzed in Cox-proportional hazards models; multivariate models included known predictors of outcome and biomarkers from univariate analyses. Sixty-nine HIV-HCV co-infected persons with available pre-LT samples were tested: median (IQR) CD4+ T-cell count was 286 (210-429) cells mm-3; 6 (9%) had detectable HIV RNA. Median (IQR) follow-up was 2.1 (0.7-4.0) years, 29 (42%) people died, 35 (51%) had graft loss, 22 (32%) were treated for acute rejection, and 14 (20%) had severe recurrent HCV. In multivariate models, sCD14 levels were significantly lower in persons with graft loss post-LT (HR 0.10 [95%CI 0.02-0.68]). IL-10 levels were higher in persons with rejection (HR 2.10 [95%CI 1.01-4.34]). No markers predicted severe recurrent HCV. Monocyte activation pre-LT may be mechanistically linked to graft health in HIV-HCV co-infection.
Project description:HIV-1 elite controllers maintain undetectable levels of viral replication in the absence of antiretroviral therapy, but their underlying immunological and virological characteristics may vary. Here, we used a whole-genome transcriptional profiling approach to characterize gene expression signatures of CD4 T cells from an unselected cohort of elite controllers. In the majority of elite controllers, transcriptional profiles were similar to HAART-treated patients, while being different from HIV-1 negative persons. Yet, a smaller proportion of elite controllers showed an opposite gene expression pattern that was indistinguishable from HIV-1 negative persons, but different from HAART-treated individuals. Elite controllers with this gene expression signature had significantly higher CD4 T cell counts, smaller levels of HIV-1-specific CD8+ T cell responses and tended to have lower residual HIV-1 viremia as determined by ultra-sensitive single-digit PCR, but did not differ from other elite controllers in terms of HLA class I alleles, age or sex. Thus, these data identify a specific subgroup of elite controllers whose clinical, immunological and gene expression characteristics approximate those of HIV-1 negative persons. Overall design: PBMC from study persons were stained with monoclonal antibodies against CD3, CD4 and HLA-DR, and subsequently subjected to live sorting at 70 psi using an ARIA cell sorting device (Becton Dickinson) located in a specifically designated biosafety cabinet. Following mRNA extraction form the sorted cells (RNAeasy kit, Qiagen), whole genome transcriptional profiling was performed using WG-DASL microarrays (Illumina) according to standard protocols. We included an unselected cohort of elite controllers (n = 12) and two background populations of HIV-1 negative persons (n = 9) and HIV-1 infected persons effectively treated with HAART (n = 14). Four replicates were included in the study.
Project description:HIV-1 elite controllers maintain undetectable levels of viral replication in the absence of antiretroviral therapy, but their underlying immunological and virological characteristics may vary. Here, we used a whole-genome transcriptional profiling approach to characterize gene expression signatures of CD4 T cells from an unselected cohort of elite controllers. In the majority of elite controllers, transcriptional profiles were similar to HAART-treated patients, while being different from HIV-1 negative persons. Yet, a smaller proportion of elite controllers showed an opposite gene expression pattern that was indistinguishable from HIV-1 negative persons, but different from HAART-treated individuals. Elite controllers with this gene expression signature had significantly higher CD4 T cell counts, smaller levels of HIV-1-specific CD8+ T cell responses and tended to have lower residual HIV-1 viremia as determined by ultra-sensitive single-digit PCR, but did not differ from other elite controllers in terms of HLA class I alleles, age or sex. Thus, these data identify a specific subgroup of elite controllers whose clinical, immunological and gene expression characteristics approximate those of HIV-1 negative persons. PBMC from study persons were stained with monoclonal antibodies against CD3, CD4 and HLA-DR, and subsequently subjected to live sorting at 70 psi using an ARIA cell sorting device (Becton Dickinson) located in a specifically designated biosafety cabinet. Following mRNA extraction form the sorted cells (RNAeasy kit, Qiagen), whole genome transcriptional profiling was performed using WG-DASL microarrays (Illumina) according to standard protocols. We included an unselected cohort of elite controllers (n = 12) and two background populations of HIV-1 negative persons (n = 9) and HIV-1 infected persons effectively treated with HAART (n = 14). Four replicates were included in the study.
Project description:The significance of elevated plasma levels of bacterial lipopolysaccharide (LPS) in persons with chronic HIV infection remains undefined. We measured LPS levels by use of limulus lysate assay, and DNA sequences encoding bacterial ribosomal 16S RNA (16S rDNA) were assessed by quantitative polymerase chain reactions in plasma samples obtained from 242 donors. Plasma levels of 16S rDNA were significantly higher in human immunodeficiency virus (HIV)-infected subjects than in uninfected subjects, and they correlated with LPS levels. Higher levels of 16S rDNA were associated with higher levels of T cell activation and with lower levels of CD4 T cell restoration during antiretroviral therapy. Antiretroviral therapy reduces but does not fully normalize plasma levels of bacterial 16S rDNA, an index of microbial translocation from the gastrointestinal tract. High levels of 16S rDNA during therapy are strongly associated with reduced increases in the CD4(+) T lymphocyte count, irrespective of plasma HIV RNA levels. These findings are consistent with the importance of microbial translocation in immunodeficiency and T cell homeostasis in chronic HIV infection.
Project description:HIV-infected subjects on highly active antiretroviral therapy (HAART) are susceptible to comorbid microbial infections in the oral cavity. We observed that primary oral epithelial cells (POECs) isolated from HIV+ subjects on HAART grow more slowly and are less innate immune responsive to microbial challenge when compared with POECs from normal subjects. These aberrant cells also demonstrate epigenetic differences that include reduction in histone deacetylase 1 (HDAC-1) levels and reduced total DNA methyltransferase (DNMT) activity specific to enzymes DNMT1 and DNMT3A. The DNMT activity correlates well with global DNA methylation, indicating that aberrant DNMT activity in HIV+ (on HAART) POECs leads to an aberrantly methylated epithelial cell phenotype. Overall, our results lead us to hypothesize that, in patients with chronic HIV infection on HAART, epigenetic changes in key genes result in increased vulnerability to microbial infection in the oral cavity.
Project description:HIV-1-infected persons are at higher risk of lower respiratory tract infections than HIV-1-uninfected individuals. This suggests strongly that HIV-infected persons have specific impairment of pulmonary immune responses, but current understanding of how HIV alters pulmonary immunity is incomplete. Alveolar macrophages (AMs), comprising small and large macrophages, are major effectors of innate immunity in the lung. We postulated that HIV-1 impairs pulmonary innate immunity through impairment of AM physiological functions. AMs were obtained by bronchoalveolar lavage from healthy, asymptomatic, antiretroviral therapy-naive HIV-1-infected and HIV-1-uninfected adults. We used novel assays to detect in vivo HIV-infected AMs and to assess AM functions based on the HIV infection status of individual cells. We show that HIV has differential effects on key AM physiological functions, whereby small AMs are infected preferentially by the virus, resulting in selective impairment of phagocytic function. In contrast, HIV has a more generalized effect on AM proteolysis, which does not require direct viral infection. These findings provide new insights into how HIV alters pulmonary innate immunity and the phenotype of AMs that harbors the virus. They underscore the need to clear this HIV reservoir to improve pulmonary immunity and reduce the high incidence of lower respiratory tract infections in HIV-1-infected individuals.
Project description:Indoleamine 2,3-dioxygenase (IDO), which is mainly expressed in activated dendritic cells, catabolizes tryptophan to kynurenine and other downstream catabolites. It is known to be an immune mediator in HIV pathogenesis. The impact of anti-retroviral therapy on its activity has not been well established.We measured systemic IDO activity (the ratio of plasma kynurenine to tryptophan) in HIV-infected patients before and after highly active antiretroviral therapy (HAART) and its association with a microbial translocation marker, soluble CD14 (sCD14).Among 76 participants, higher baseline IDO activity was associated with lower CD4+ T cell counts (P<0.05) and higher plasma sCD14 levels (P<0.001). After 1 year of HAART, IDO activity decreased significantly (P<0.01), but was still higher than in healthy controls (P<0.05). The baseline IDO activity did not predict CD4+ T cell recovery after 1 year of therapy. The percentages of myeloid and plasmacytoid dendritic cells were not correlated with IDO activity.IDO activity is elevated in HIV-infected patients, which is partially associated with microbial translocation. HAART reduced, but did not normalize the activity of IDO.
Project description:In treatment-naive, human immunodeficiency virus (HIV)-infected persons, combination antiretroviral therapy (cART) incorporating raltegravir (RAL) is highly effective for virologic suppression, but characteristics of immunologic recovery have not been described.We performed a 48-week substudy of 15 patients, median age 40 years, within a phase 2 randomized trial of RAL-cART in treatment-naive patients with chronic HIV infection.Plasma viral load decreased from 5.2 ± 5.3 log10 HIV RNA copies/mL to 2.2 ± 2.4 log10 copies/mL at week 4, reaching <50 copies/mL at week 8 in 13 of 15 patients. Total CD4 T cells increased at week 4, as did central memory CD4 T cells in association with reduction of the immune activation markers HLA-DR and CD38 and immune exhaustion marker PD1 in CD4 and CD8 T cells. Naive CD4 T cells increased at week 24 with appearance of HIV gag-specific interleukin 2, interferon-?, and CD107a responses in CD4 and CD8 T cells at week 48. Plasma lipopolysaccharide and soluble CD14 decreased, but at week 48 were elevated as compared to healthy volunteers. Altogether, the week 48 immune profile was more favorable in patients taking RAL-cART than in patients treated with non-RAL-cART.RAL in first-line treatment regimens results in rapid immune reconstitution with residual low-level microbial translocation.
Project description:IL-1? is an important mediator of innate inflammatory responses and has been shown to contribute to liver injury in a number of etiologies. HIV patients have increased necroinflammation and more rapid fibrosis progression in chronic liver injury compared to non-HIV-infected patients. As the resident liver macrophage is critical to the IL-1? response to microbial translocation in chronic liver disease, we aim to examine the impact of HIV-1 and LPS stimulation on the IL-1? response of the resident hepatic macrophages. We isolated primary human liver macrophages from liver resection specimens, treated them with HIV-1BaL and/or LPS ex vivo, examined the IL-1? response, and then studied underlying mechanisms. Furthermore, we examined IL-1? expression in liver tissues derived from HIV-1 patients compared to those with no underlying liver disease. HIV-1 up-regulated TLR4 and CD14 expression on isolated primary CD68+ human liver macrophages and contributed to the IL-1? response to LPS stimulation as evidenced by TLR4 blocking. Nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) was shown to be involved in the IL-1? response of liver macrophages to HIV-1 infection and NLRP3 blocking experiments in primary CD68+ liver macrophages confirmed the contribution of the NLRP3-caspase 1 inflammatory signaling pathway in the IL-1? response. High in situ IL-1? expression was found in CD68+ cells in human liver tissues from HIV-1-infected patients, suggesting a critical role of IL-1? responses in patients infected by HIV. HIV infection sensitizes the IL-1? response of liver macrophages to LPS through up-regulation of CD14 and TLR4 expression and downstream activation of the NLRP3-caspase 1 pathway. These findings have implications for enhanced immune activation in HIV+ patients and mechanisms for rapid fibrosis progression in patients with chronic liver injury.