Untreated HIV-infected Individuals Research Articles

16S rDNA PCR in diagnosis of Lemierre's syndrome

In their Grand Round paper, Krutika Kuppalli and colleagues have omitted an important device for the diagnosis of Lemierre’s syndrome. Molecular methods, including broad-range 16S rDNA PCR, are increasingly being used 1 Amoroso A, Etienne-Mesubi M, Edozien A, Mesubi OO, Guberski T. HIV-1 drug resistance in antiretroviral-naive patients in sub-Saharan Africa. Lancet Infect Dis 2012; 12: 585–86. 2 Hamers RL, Wallis CL, Kityo C, et al. HIV-1 drug resistance in antiretroviral-naive individuals in sub-Saharan Africa after rollout of antiretroviral therapy: a multicentre observational study. Lancet Infect Dis 2011; 11: 750–59. 3 Bennett DE, Jordan MR, Bertagnolio S, et al. HIV drug resistance early warning indicators in cohorts of individuals starting antiretroviral therapy between 2004 and 2009: World Health Organization global report from 50 countries. Clin Infect Dis 2012; 54 (suppl 4): 280–89. 4 Gupta RK, Sultan BJ, Hill A, et al. Global trends in antiretroviral resistance in untreated HIV-1 infected individuals following ART roll-out in resource-limited settings: a global collaborative study and meta-regression analysis. Lancet 2012; 380: 1250–58. 5 WHO. WHO HIV drug resistance report 2012. http://www.who.int/hiv/pub/drugresistance/ report2012/en/index.html (accessed Sept 10, 2012) 6 Hamers RL, Kityo C, Lange JM, de Wit TF, Mugyenyi P. Global threat from drug resistant HIV in sub-Saharan Africa. BMJ 2012; 344: e4159. on culture-negative specimens from normally sterile sites in developed countries. The authors acknowledge that a high index of clinical suspicion is key to the diagnosis of Lemierre’s syndrome. However, in my experience, the diagnosis is almost always delayed, either due to atypical presentation (ie, many suppurative lesions in the absence of a history of upper respiratory tract illness) or because the causative organism(s) cannot be recovered as a result of their fastidious nature or previous antibiotic treatment. 16S rDNA PCR has two major advantages in the management of patients presenting with a febrile illness and suppurative lesions, especially those who have received previous antibiotic treatment. First, the method encompasses several genera of bacteria, enabling diagnosis of other bacterial infections presenting with similar clinical features, such as Staphylococcus aureus, group A streptococci, and Streptococcus pneumoniae. Second, because the test detects molecular material from bacteria, previous antibiotic treatment would not inter fere with the diagnosis, as is the case with conventional culture methods. Molecular methods can also be used on throat swab for the diagnosis of Lemierre’s syndrome, but results should be interpreted with caution. As is the case with any other laboratory tests, molecular methods do have limitations regarding their sensitivity and specifi city. Nevertheless, 16S rDNA PCR has been shown to increase diagnostic yield. Although not perfect, if available, molecular methods should be used alongside routine culture methods in cases with a high probability of the illness being Lemierre’s syndrome.

Pretreatment antiretroviral exposure from recreational use

The international community has overcome many obstacles in making HIV antiretroviral (ARV) medication available globally, but ARV resistance in treatment-naive individuals remains an implementation challenge. The subject of many recent reports,1-3 worries abound that pretreatment ARV resistance is related to treatment failure and that further increases in the rates of pretreatment ARV resistance might “jeopardise the global HIV response”.1,2 Largely attributed to transmitted resistance, pretreatment ARV exposure such as inadequate treatment outside of sanctioned care networks is believed to be a contributing factor.3 While investigating HIV-risk behaviour in South Africa,4 we learned of a preventable form of pretreatment ARV exposure that has gone largely unreported and may accelerate rates of pretreatment ARV resistance: the recreational use of ARVs referred to by our informants as “whoonga”. Whereas whoonga has received significant media attention since 2010, the first and only report in the medical literature documenting the recreational use of ARVs appeared years earlier from the United States. In discussions with HIV-infected individuals in Miami about prescription drug diversion, Inciardi and colleagues learned that some individuals abuse efavirenz for its “intoxicating” effects and use ritonavir to enhance the effects of illicit drugs such as methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA/ecstasy).5 Claims about the psychoactive effects of these ARVs are supported by scientific case reports.6,7 Similar ARV abuse patterns in South Africa have been reported in the social science literature and news media. Larkan and colleagues provide an account of individuals smoking efavirenz in Western Cape and summarise media reports that ARVs are combined with illicit drugs such as opiates, methamphetamine, and/or marijuana to make drug cocktails.8 Whoonga, believed to be one such cocktail, brought media attention to the problem of recreational ARV use in Kwazulu-Natal because of its addictive potential, its association with criminal activity, and the challenge it posed to ARV rollout.9 Even local experts who maintain that whoonga is heroin and does not contain ARVs acknowledge that a number of South African drug abusers use ARVs recreationally.10 Although essentially a substance abuse problem, the implications for HIV treatment are broad. For example, diversion of ARVs, in addition to impacting adherence, reduces ARV supply and limits access to treatment. Criminal behaviour related to diversion of ARVs endangers patients and healthcare providers while deterring others from seeking care. Finally, the recreational use of ARVs further stigmatises HIV-infected patients and their communities and may undermine donor willingness to fund ARV treatment.8 In addition to these impacts, when untreated HIV-infected individuals are exposed to ARVs recreationally, they are at risk for acquiring resistance.8 Mutations conferring resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) such as efavirenz are among the most common in individuals with pretreatment ARV resistance.1-3 Interestingly, serum concentrations of ARVs including efavirenz have been detected in some HIV-infected individuals with pretreatment ARV resistance who deny prior history of ARV treatment.3 To help explain some of these findings, researchers may wish to inquire specifically about recreational ARV use or use of drug cocktails when assessing pretreatment ARV exposure. Expanding pretreatment ARV resistance screening will help to minimize the risk that this form of pretreatment ARV exposure poses; however, a comprehensive strategy to investigate this problem also involves expanding substance abuse research. Existing substance abuse surveillance methods have not reported on the phenomenon,11,12 and they may need to be improved if we are to understand the extent of pretreatment ARV exposure from recreational ARV use. Systematic research is also needed to explore the chemical makeup of South African street drugs, the abuse liability of ARVs, and the bioavailability and likelihood of developing resistance when ARVs are smoked or otherwise administered inappropriately. Given the high prevalence and complex medical, psychosocial, and political context of HIV in southern Africa, it is important that treatment strategies adapt to emerging issues like recreational ARV use. We may decrease the recreational use of ARVs, decrease drug diversion, and improve adherence to HIV treatment if we avoid ARVs used recreationally when developing ARV treatment guidelines or distribute ARVs to patients in a way that minimizes the potential for misuse. The recreational use of ARVs also serves as a reminder that ARV treatment is not synonymous with HIV treatment and demonstrates the importance of access to effective community-based mental health and substance abuse services.

Circulating levels of HMGB1 are correlated strongly with MD2 in HIV-infection: Possible implication for TLR4-signalling and chronic immune activation

Progressive HIV infection is characterized by profound enterocyte damage, microbial translocation and chronic immune activation. We aimed to test whether High Mobility Group Box protein 1(HMGB1), a marker of cell death, alone, or in combination with LPS, might contribute to HIV-associated immune activation and progression. Altogether, 29 untreated HIV-infected individuals, 25 inflammatory bowel disease (IBD) patients and 30 controls were included. HIV-infected patients had lower plasma LPS levels than IBD patients, but higher levels of soluble CD14 and Myeloid Differentiation (MD) 2, which interacts with TLR4 to initiate LPS-signalling. Furthermore, plasma levels of HMGB1 and MD2 were correlated directly within the HIV-infected cohort (r = 0.89, P < 0.001) and the IBD-cohort (r = 0.85, P < 0.001), implying HMGB1 signalling through the MD2/TLR4-pathway. HMGB1 and LPS, although not inter-correlated, were both moderately (r = 0.4) correlated with CD38 density on CD8+ T cells in HIV progressors. The highest levels of CD38 density and MD2 were found in progressors with plasma levels of both LPS and HMGB1 above the fiftieth percentile. Our results could imply that, in some patients, immune activation is triggered by microbial translocation, in some by cell death and in some by HMGB1 in complex with bacterial products through activation of the MD2/TLR4-pathway.

Evaluation of the dual IFNγ/IL-2 fluorospot-assay with flow cytometry for detection of HLA-restricted HIV-specific T-cell responses in HIV controllers

Background: The IFNγ ELISpot assay is used widely for high through-put screening of HIV-specific responses in studies of HIV infection and vaccine studies. However, dual production of IFN/IL-2 and increased proliferative capacity may be associated with better natural control of HIV infection. We evaluated a novel fluorospot assay enabling the identification of dual IFNγ/ IL-2 producing antigen-specific cells and compared it with intracellular cytokine staining by standard flow cytometry in individuals with natural control of HIV-infection. Methods: PBMC from five untreated HIV-infected individuals were stimulated overnight with HIV peptides or controls in dual IFN/IL-2 pre-coated plates. Peptide arrays were specifically selected based on the individual HLA type. Secreted IFNγ and IL-2 were detected using fluorescent-conjugated antibodies. Fluorescent spots were enumerated on the iSpot AID reader. Responses were considered positive if >50 spots/million cells SFU after background subtraction.Positive responses were then evaluated by flow cytometry using the Gallios flow cytometer. Results: Dual IL-2/IFNγ producing cells were detected to anti-CD3- stimulated PBMC from all patients. IFNγ responses alone were detected to 35 of 136 HLA-restricted peptides tested (median =73, 52-4190 SFU) across the 5 patients (1/19, 5/19, 7/28, 9/15 and 13/55 for each patient), while IL-2 responses were either low grade or undetectable for the majority of HIV peptides tested. Dual IFNγ/IL-2 producing HIV-specific T cells were not detected using the fluorospot assay. 24/35 peptides induced CD8 T cell- IFNγ production by flow cytometry. Conclusion: HIV-specific mono-IFNγ responses were detected using the novel fluorospot assay. However limited HIV-specific dual IFNγ/IL-2 responses were detected in this patient group. A greater number of epitope-specific positive responses were detected in the fluorospot compared with flow cytometry suggesting the fluorospot may be more sensitive in detecting a greater breadth of epitope-specific T cell responses, and therefore better for screening purposes than flow cytometric methods.

Regulatory B cells are induced in untreated HIV-1 infection and suppress HIV-1 specific T cell responses

Background Regulatory B cells (Breg), the B cells producing interleukin 10 (IL-10), have been identified in mice and humans. Mouse Breg can suppress innate and T cell responses and are implicated in pathogenesis of some autoimmune diseases and immune evasion of some pathogens. However, the role of Breg in humans is less clear. Methods PBMC and gut biopsy samples were obtained from healthy donors and HIV infected individuals. Flow cytometry and Luminex were used to quantify cytokine production. Flow cytometry were used to analyze Breg’s phenotype. Results Breg were elevated in both peripheral blood and gut tissue of untreated HIV-1 infected individuals and the elevation correlated with viral load in early HIV-1 infection. Breg from HIV-1 infected individuals were CD19 + TIM-1 + .Antiretroviral therapy could reduce elevated Breg frequency. Treatment of B cells from healthy donors with microbial translocation products could differentiate them toward a Breg phenotype. Ex vivo Bregs from HIV-1 infected individuals suppressed cytokine production /degranulation of HIV-1 specific T cells that was in part IL-10 dependent. Conclusion

The Characteristics of Th1/Th2 Cytokine Receptors on Monocytes in Untreated Patients of Long Term Nonprogressor or Chronic HIV Infection

Monocytes/macrophages play crucial roles in immunity to microorganisms and are one of the important targets for human immunodeficiency virus (HIV) infection. The phenotypes and function of monocytes in HIV-infected patients were poorly determined. We herein detected the expression of Th1/Th2 cytokine receptors on monocyte subsets in the untreated HIV-infected patients of either long term nonprogressor (LTNP) or chronic infection (CHI). CD14(+)CD16(-) monocytes were significantly increased and CD14(+)CD16(+) monocytes were reduced in patients of LTNP or CHI compared with healthy control. IL-6R expression on CD14(+)CD16(-) monocytes were decreased in patients of LTNP or CHI, whereas IL-4R and IL-10R expression on both CD14(+)CD16(-) and CD14(+)CD16(+) monocyte subsets were increased in patients with LTNP or CHI, as determined by flow cytometry and real time PCR assays. The decreased IL-6R expression and enhanced IL-4R and IL-10R expression were also observed on CD4(+) T cells of these patients, indicating that these changes in monocytes are not cell-specific. CD14(+)CD16(-) monocytes of HIV-infected patients produced less TNF-α and IL-1β but identical levels of IL-6, and IL-12 as the control after IFN-γ/LPS stimulation. However, in the presence of IL-4 or IL10, CD14(+)CD16(-) monocytes of HIV-infected patients produced more TNF-α, IL-6, IL-12 or Il-1β after IFN-γ/LPS stimulation than the healthy control, supporting the impaired IL-4R and IL-10R signal pathways in patients with LTNP and CHI. Therefore, our present study offered the basic information for the Th1/Th2 cytokine receptor expression and function on monocyte subsets in untreated HIV-infected individuals.

Indicators of therapeutic effect in FIT-06, a Phase II trial of a DNA vaccine, GTU®-Multi-HIVB, in untreated HIV-1 infected subjects

BackgroundCombination highly active antiretroviral therapy (HAART) has significantly decreased HIV-1 related morbidity and mortality globally transforming HIV into a controllable condition. HAART has a number of limitations though, including limited access in resource constrained countries, which have driven the search for simpler, affordable HIV-1 treatment modalities. Therapeutic HIV-1 vaccines aim to provide immunological support to slow disease progression and decrease transmission. We evaluated the safety, immunogenicity and clinical effect of a novel recombinant plasmid DNA therapeutic HIV-1 vaccine, GTU®-multi-HIVB, containing 6 different genes derived from an HIV-1 subtype B isolate. Methods63 untreated, healthy, HIV-1 infected, adults between 18 and 40 years were enrolled in a single-blinded, placebo-controlled Phase II trial in South Africa. Subjects were HIV-1 subtype C infected, had never received antiretrovirals, with CD4≥350cells/mm3 and pHIV-RNA≥50copies/mL at screening. Subjects were allocated to vaccine or placebo groups in a 2:1 ratio either administered intradermally (ID) (0.5mg/dose) or intramuscularly (IM) (1mg/dose) at 0, 4 and 12 weeks boosted at 76 and 80 weeks with 1mg/dose (ID) and 2mg/dose (IM), respectively. Safety was assessed by adverse event monitoring and immunogenicity by HIV-1-specific CD4+ and CD8+ T-cells using intracellular cytokine staining (ICS), pHIV-RNA and CD4 counts. ResultsVaccine was safe and well tolerated with no vaccine related serious adverse events. Significant declines in logpHIV-RNA (p=0.012) and increases in CD4+ T cell counts (p=0.066) were observed in the vaccine group compared to placebo, more pronounced after IM administration and in some HLA haplotypes (B*5703) maintained for 17 months after the final immunisation. ConclusionsThe GTU®-multi-HIVB plasmid recombinant DNA therapeutic HIV-1 vaccine is safe, well tolerated and favourably affects pHIV-RNA and CD4 counts in untreated HIV-1infected individuals after IM administration in subjects with HLA B*57, B*8101 and B*5801haplotypes.

Chronic Immune Activation in HIV-1 Infection Contributes to Reduced Interferon Alpha Production via Enhanced CD40:CD40 Ligand Interaction

Although a signature of increased interferon (IFN-)alpha production is observed in HIV-1 infection, the response of circulating plasmacytoid dendritic cells (PDC) to Toll-like receptor ligand stimulation is substantially impaired. This functional PDC deficit, which we specifically observed in HIV-1 infected individuals with less than 500 CD4+ T cells/µl, is not well understood. We provide evidence that the peripheral IFN-alpha production in HIV-1 infection is actively suppressed by the enhanced interaction of CD40 ligand (CD40L), a member of the tumor necrosis factor family, and its receptor CD40, which are both upregulated upon immune activation. Plasma levels of soluble CD40L were significantly higher in untreated HIV-1 infected individuals (n = 52) than in subjects on long-term antiretroviral therapy (n = 62, p<0.03) and in uninfected control donors (n = 16, p<0.001). Concomitantly, cell-associated CD40L and the expression of the receptor CD40 on the PDC were significantly upregulated in HIV-1 infection (p<0.05). Soluble and cell-associated CD40L inhibited the PDC-derived IFN-alpha production by CpG oligodeoxynucleotides dose-dependently. This suppressive effect was observed at much lower, physiological CD40L concentrations in peripheral blood mononuclear cells (PBMC) of HIV-1 infected individuals compared to controls (p<0.05). The CpG-induced IFN-alpha production in PBMC of HIV-1 infected donors was directly correlated with PDC and CD4+ T cell counts, and inversely correlated with the viral loads (p<0.001). In HIV-1 infected donors with less than 500 CD4+ T cells/µl, the CpG-induced IFN-alpha production was significantly correlated with the percentage of CD40-expressing PDC and the level of CD40 expression on these cells (p<0.05), whereas CD40L plasma levels played a minor role. In addition, low-dose CD40L contributed to the enhanced production of interleukin 6 and 8 in PBMC of HIV-1 infected donors compared to controls. Our data support the conclusion that the chronic immune activation in HIV-1 infection impairs peripheral PDC innate immune responses at least in part via enhanced CD40:CD40L interactions.

Viremic HIV infected individuals with high CD4 T cells and functional envelope proteins show anti-gp41 antibodies with unique specificity and function.

BackgroundCD4 T-cell decay is variable among HIV-infected individuals. In exceptional cases, CD4 T-cell counts remain stable despite high plasma viremia. HIV envelope glycoprotein (Env) properties, namely tropism, fusion or the ability to induce the NK ligand NKp44L, or host factors that modulate Env cytopathic mechanisms may be modified in such situation.MethodsWe identified untreated HIV-infected individuals showing non-cytopathic replication (VL>10,000 copies/mL and CD4 T-cell decay<50 cells/µL/year, Viremic Non Progressors, VNP) or rapid progression (CD4 T-cells<350 cells/µL within three years post-infection, RP). We isolated full-length Env clones and analyzed their functions (tropism, fusion activity and capacity to induce NKp44L expression on CD4 cells). Anti-Env humoral responses were also analyzed.ResultsEnv clones isolated from VNP or RP individuals showed no major phenotypic differences. The percentage of functional clones was similar in both groups. All clones tested were CCR5-tropic and showed comparable expression and fusogenic activity. Moreover, no differences were observed in their capacity to induce NKp44L expression on CD4 T cells from healthy donors through the 3S epitope of gp41. In contrast, anti- Env antibodies showed clear functional differences: plasma from VNPs had significantly higher capacity than RPs to block NKp44L induction by autologous viruses. Consistently, CD4 T-cells isolated from VNPs showed undetectable NKp44L expression and specific antibodies against a variable region flanking the highly conserved 3S epitope were identified in plasma samples from these patients. Conversely, despite continuous antigen stimulation, VNPs were unable to mount a broad neutralizing response against HIV.ConclusionsEnv functions (fusion and induction of NKp44L) were similar in viremic patients with slow or rapid progression to AIDS. However, differences in humoral responses against gp41 epitopes nearby 3S sequence may contribute to the lack of CD4 T cell decay in VNPs by blocking the induction of NKp44L by gp41.

Even at High CD4-Cell Counts, Mortality Rates Are High in Untreated HIV Infection

Only very limited data exist on causes of death among untreated HIV-infected individuals in sub-Saharan Africa, especially those with high CD4-cell

APOL1 genetic variants in focal segmental glomerulosclerosis and HIV-associated nephropathy.

Trypanolytic variants in APOL1, which encodes apolipoprotein L1, associate with kidney disease in African Americans, but whether APOL1-associated glomerular disease has a distinct clinical phenotype is unknown. Here we determined APOL1 genotypes for 271 African American cases, 168 European American cases, and 939 control subjects. In a recessive model, APOL1 variants conferred seventeenfold higher odds (95% CI 11 to 26) for focal segmental glomerulosclerosis (FSGS) and twenty-nine-fold higher odds (95% CI 13 to 68) for HIV-associated nephropathy (HIVAN). FSGS associated with two APOL1 risk alleles associated with earlier age of onset (P = 0.01) and faster progression to ESRD (P < 0.01) but similar sensitivity to steroids compared with other subjects. Individuals with two APOL1 risk alleles have an estimated 4% lifetime risk for developing FSGS, and untreated HIV-infected individuals have a 50% risk for developing HIVAN. The effect of carrying two APOL1 risk alleles explains 18% of FSGS and 35% of HIVAN; alternatively, eliminating this effect would reduce FSGS and HIVAN by 67%. A survey of world populations indicated that the APOL1 kidney risk alleles are present only on African chromosomes. In summary, African Americans carrying two APOL1 risk alleles have a greatly increased risk for glomerular disease, and APOL1-associated FSGS occurs earlier and progresses to ESRD more rapidly. These data add to the evidence base required to determine whether genetic testing for APOL1 has a use in clinical practice.

Immunogenic and tolerogenic signatures in human immunodeficiency virus (HIV)-infected controllers compared with progressors and a conversion strategy of virus control

Epidemiological studies have identified a small cohort of controllers of human immunodeficiency virus (HIV)-1 infection, who without treatment have no detectable virus, and others who progress at a variable rate. The objective of this study was to distinguish immune signatures in HIV controllers and progressors, by evaluating tolerogenic and immunogenic factors in untreated HIV-1 infected individuals. The recruited population was divided into putative elite controllers (PEC), long-term non-progressors (LTNP), normal progressors (NP) and fast progressors (FP). The proportion of regulatory T cells [T(regs) , CD4+ CD25+ forkhead box P3 (FoxP3+)], programmed death (PD)-1 and cytotoxic T lymphocyte antigen (CTLA)-inhibitory molecules and CD40L, CD69 and Ki67 activation markers were evaluated in peripheral blood mononuclear cells (PBMC) by flow cytometry. Significant differences were found between HIV controllers and HIV progressors, with up-regulation of T(regs) , PD-1 and CTLA-4 and decrease of CD40L expression in progressors compared with controllers. Expression of CD40L and concentrations of interleukin (IL)-6, CCL-3, and CCL-4 were significantly higher in PEC and LTNP than in NP and FP. In an attempt to convert immune signatures of progressors to those of controllers, seven agents were used to stimulate PBMC from the four cohorts. Treatment with CD40L and IL-4 or PD-1 antibodies in vitro were most effective in converting the immune signatures of progressors to those observed in controllers by down-regulating T(regs) and up-regulating CD40L expression in CD4+ T cells. The conversion concept merits translation to in vivo immune control of HIV infection.

Loss of balance between T helper type 17 and regulatory T cells in chronic human immunodeficiency virus infection

The aim of this study is to characterize the changes of CD4(+) CD25(high) forkhead box P3 (FoxP3(+) ) regulatory T cells (T(reg) ), interleukin (IL)-17 secreting T helper type 17 (Th17) cell frequencies and the balance of these two subsets in a cohort of chronic human immunodeficiency virus type 1 (HIV-1)-infected patients in China. A total of 115 untreated chronic HIV-infected individuals and 32 healthy donors were recruited in this study. Peripheral blood mononuclear cells were isolated from ethylenediamine tetracetic acid (EDTA) anti-coagulated fresh whole blood and stained to characterize the frequencies of T(reg) and Th17. Of a total 115 patients, 42 individuals including 10 elite controllers were followed-up for more than 1 year, and changes of T(reg) and Th17 frequencies were analysed over time. The continuous loss of Th17 cells was accompanied by a concomitant rise in the frequency of T(reg) cells, resulting in a loss of Th17/T(reg) balance during the progressive HIV infection. Meanwhile, the T(reg) levels, Th17 levels and Th17/T(reg) ratios of the elite controller group were comparable to those of the HIV-1 negative controls in the follow-up study. Additionally, we demonstrated that loss of balance between Th17 and T(reg) is associated with an earlier CD4 T cell decline during the course of HIV infection. Our results indicate that a loss of immune-balance of Th17 to T(reg) during HIV-1 disease progression and the persistence of such an immune-balance in the elite controllers may have a critical role in HIV-1 infection and further shed new light into understanding the pathogenesis of HIV-1.

Endotoxemia Is Associated with Altered Innate and Adaptive Immune Responses in Untreated HIV-1 Infected Individuals

BackgroundMicrobial 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.Methodology/Principal FindingsThis 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-α-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.Conclusions/SignificanceLPS 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.

Influence of HIV Infection on Cytomegalovirus-Specific Immunity: T-Cell Responses to Pp65 and Ie1 before and after Haart May Refect Altered Cytomegalovirus Biology

Data are inconclusive whether treatment with HAART induces functional recovery of HIV-specific T-cells. Since the introduction of HAART, a marked decrease of cytomegalovirus (CMV) disease - for which untreated HIV-infected individuals are at increased risk - is observed, suggesting that this treatment influences CMV-specific T-cell immunity. To study potential functional recovery of HIV- and CMV-specific T-cells, CD4(+) and CD8(+) T-cell responses were measured longitudinally after in vitro expansion using gag, pp65 and IE1 peptide pools, during HIV infection and after long-term HAART. HIV-specific T-cell function, measured by interferon (IFN)-γ production, was low after initiation of HAART. Interestingly, the cytotoxic function - measured by CD107a expression - of these T-cells temporarily increased after start of treatment, suggesting some functional recovery. The pp65-specific CD8(+) T-cell responses tended to decrease during HIV infection, whereas pp65-specific CD4(+) T-cell responses decreased upon treatment with HAART. Both pp65-specific CD4(+) and CD8(+) T-cell responses were low after initiation of HAART compared to healthy controls. By contrast, IE1-specific CD4(+) T-cell responses increased during the course of HIV infection. After initiation of HAART, IE1-specific T-cell responses decreased, but IE1-specific CD8(+) T-cells seemed increased compared to healthy controls. This study suggests that HIV-infection leads to an altered CMV biology, affecting pp65- and IE1-specific T-cell responses in a different way, which is not restored by treatment with long-term HAART.

HIV Persistence in the Gut Mucosa of HIV-Infected Subjects Undergoing Antiretroviral Therapy Correlates with Immune Activation and Increased Levels of LPS

We investigated the relationship between viral persistence in the gut, microbial translocation, and T cell activation during chronic HIV infection. Plasma levels of LPS, fraction of circulating CD8+CD38+ T cells, and levels of HIV-DNA in rectosigmoid biopsies and peripheral blood mononuclear cells were determined in 22 HIV-infected individuals and 10 healthy controls. We found that in untreated HIV-infected individuals, HIV-DNA load was higher in the gut mucosa than in the blood. Also, ART-treated patients exhibited lower levels of LPS and CD8+CD38+ T cells than untreated patients, but higher levels than controls. In ART-treated individuals, the level of HIV-DNA in the gut correlated with levels of LPS and fraction of CD8+CD38+ T cells. We concluded that in ART-treated individuals, higher levels of gut-associated HIV-DNA are associated with persistent immune activation and microbial translocation.

Disruption of intestinal CD4+ T cell homeostasis is a key marker of systemic CD4+ T cell activation in HIV-infected individuals.

HIV infection is associated with depletion of intestinal CD4(+) T cells, resulting in mucosal immune dysfunction, microbial translocation, chronic immune activation, and progressive immunodeficiency. In this study, we examined HIV-infected individuals with active virus replication (n = 15), treated with antiretroviral therapy (n = 13), and healthy controls (n = 11) and conducted a comparative analysis of T cells derived from blood and four gastrointestinal (GI) sites (terminal ileum, right colon, left colon, and sigmoid colon). As expected, we found that HIV infection is associated with depletion of total CD4(+) T cells as well as CD4(+)CCR5(+) T cells in all GI sites, with higher levels of these cells found in ART-treated individuals than in those with active virus replication. While the levels of both CD4(+) and CD8(+) T cell proliferation were higher in the blood of untreated HIV-infected individuals, only CD4(+) T cell proliferation was significantly increased in the gut of the same patients. We also noted that the levels of CD4(+) T cells and the percentages of CD4(+)Ki67(+) proliferating T cells are inversely correlated in both blood and intestinal tissues, thus suggesting that CD4(+) T cell homeostasis is similarly affected by HIV infection in these distinct anatomic compartments. Importantly, the level of intestinal CD4(+) T cells (both total and Th17 cells) was inversely correlated with the percentage of circulating CD4(+)Ki67(+) T cells. Collectively, these data confirm that the GI tract is a key player in the immunopathogenesis of HIV infection, and they reveal a strong association between the destruction of intestinal CD4(+) T cell homeostasis in the gut and the level of systemic CD4(+) T cell activation.

Long-term Nonprogressive Disease Among Untreated HIV-Infected Individuals

As of 2008, more than 33 million adults and children have been estimated to be living with human immunodeficiency virus (HIV). Among them are rare patients (<0.5%) who have remained clinically well without antiretroviral therapy after almost 20 years of infection. They maintain stable CD4 cell counts and suppressed HIV replication to levels comparable with those measured in patients receiving combination antiretroviral therapy. No known epidemiologic or behavioral factors are predictive of untreated, nonprogressive HIV infection; however, host genetics and immune response factors, most specifically HLA antigen class I-restricted HIV-specific CD8 T cells, appear to be primarily responsible for this remarkable phenotype in a majority of these individuals. These patients offer hope that durable control of HIV infection is possible and can provide important insight to inform the development of the next generation of HIV/AIDS vaccines and immune-based therapies. This article reviews clinical features of these unique patients and discusses them in the context of nonprogressors enrolled in other cohorts. Potential mechanisms underlying nonprogressive HIV infection and scientific discoveries, facilitated by the participation of these patients in clinical trials, of relevance to the design of an efficacious HIV/AIDS vaccine are also highlighted.

HIV-Induced Abnormalities in Myelopoiesis and their Recovery Following Antiretroviral Therapy

HIV-1 infection is associated with hematologic abnormalities including defective myelopoiesis. Most studies of myelopoiesis during HIV-1 infection were performed using unfractionated bone marrow-derived mononuclear cells, thus resulting in significant inter-individual variability in the numbers of cultured precursors. Here we evaluated the myelopoietic potential of circulating CD34+ progenitors by conducting a longitudinal analysis of antiretroviral therapy (ART)-induced changes of colony forming units-granulocyte and monocyte (CFU-GM) growth. Twelve HIV-infected individuals were studied longitudinally before and after initiation of ART (i.e. at a time when plasma HIV-RNA levels had become undetectable); thirty-one HIV-uninfected healthy individuals were enrolled as controls. Peripheral blood-derived CD34+ progenitors were purified by immunomagnetic sorting, and cultured in methylcellulose-based medium containing stem cell factor, granulocyte-monocyte colony-stimulating factor and interleukin-3. ART-induced changes in the proportion of CD8+ T cells expressing surface HLA-DR were also evaluated. We found that CFU-GM levels were increased in untreated HIV-infected individuals when compared to uninfected controls but declined significantly following ART, in parallel with the decline of HIV-RNA levels in plasma and with the down-regulation of HLA-DR expression on CD8+ T cells. These findings suggest that, in untreated HIV-infected individuals, chronic inflammation and/or immune activation is associated with defective myelopoiesis and accumulation of myeloid precursors. ART-induced suppression of HIV-1 replication is associated with normalization of CFU-GM levels.

Increased Levels of Platelet Microparticles in HIV-Infected Patients With Good Response to Highly Active Antiretroviral Therapy

Increased Levels of Platelet Microparticles in HIV-Infected Patients With Good Response to Highly Active Antiretroviral Therapy