Natural history of serum HIV-1 RNA levels in 330 patients with a known date of infection. The SEROCO Study Group

Population-level analysis of natural control of HIV infection in Zambia and South Africa: HPTN 071 (PopART)

INTRODUCTION

HIV controllers have low viral loads (VL) without antiretroviral treatment (ART). We evaluated viraemic control in a community-randomized trial conducted in Zambia and South Africa that evaluated the impact of a combination prevention intervention on HIV incidence (HPTN 071 [PopART]; 2013-2018).

METHODS

VL and antiretroviral (ARV) drug testing were performed using plasma samples collected 2 years after enrolment for 4072 participants who were HIV positive at the start of the study intervention. ARV drug use was assessed using a qualitative laboratory assay that detects 22 ARV drugs in five drug classes. Participants were classified as non-controllers if they had a VL ≥2000 copies/ml with no ARV drugs detected at this visit. Additional VL and ARV drug testing was performed at a second annual study visit to confirm controller status. Participants were classified as controllers if they had VLs <2000 with no ARV drugs detected at both visits. Non-controllers who had ARV drugs detected at either visit were excluded from the analysis to minimize potential confounders associated with ARV drug access and uptake.

RESULTS

The final cohort included 126 viraemic controllers and 766 non-controllers who had no ARV drugs detected. The prevalence of controllers among the 4072 persons assessed was 3.1% (95% confidence interval [CI]: 2.6%, 3.6%). This should be considered a minimum estimate, since high rates of ARV drug use in the parent study limited the ability to identify controllers. Among the 892 participants in the final cohort, controller status was associated with biological sex (female > male, p = 0.027). There was no significant association between controller status and age, study country or herpes simplex virus type 2 (HSV-2) status at study enrolment.

CONCLUSIONS

To our knowledge, this report presents the first large-scale, population-level study evaluating the prevalence of viraemic control and associated factors in Africa. A key advantage of this study was that a biomedical assessment was used to assess ARV drug use (vs. self-reported data). This study identified a large cohort of HIV controllers and non-controllers not taking ARV drugs, providing a unique repository of longitudinal samples for additional research. This cohort may be useful for further studies investigating the mechanisms of virologic control.

Changing roles of CD3 + CD8 low T cells in combating HIV-1 infection

BACKGROUND

Cluster of differentiation 8 (CD8 T) cells play critical roles in eradicating human immunodeficiency virus (HIV)-1 infection, but little is known about the effects of T cells expressing CD8 at low levels (CD8 low ) or high levels (CD8 high ) on HIV-1 replication inhibition after HIV-1 invasion into individual.

METHODS

Nineteen patients who had been acutely infected with HIV-1 (AHI) and 20 patients with chronic infection (CHI) for ≥2 years were enrolled in this study to investigate the dynamics of the quantity, activation, and immune responses of CD3 + CD8 low T cells and their counterpart CD3 + CD8 high T cells at different stages of HIV-1 infection.

RESULTS

Compared with healthy donors, CD3 + CD8 low T cells expanded in HIV-1-infected individuals at different stages of infection. As HIV-1 infection progressed, CD3 + CD8 low T cells gradually decreased. Simultaneously, CD3 + CD8 high T cells was significantly reduced in the first month of AHI and then increased gradually as HIV-1 infection progressed. The classical activation of CD3 + CD8 low T cells was highest in the first month of AHI and then reduced as HIV-1 infection progressed and entered the chronic stage. Meanwhile, activated CD38 - HLA-DR + CD8 low T cells did not increase in the first month of AHI, and the number of these cells was inversely associated with viral load ( r = -0.664, P = 0.004) but positively associated with the CD4 T-cell count ( r = 0.586, P = 0.014). Increased programmed cell death protein 1 (PD-1) abundance on CD3 + CD8 low T cells was observed from the 1st month of AHI but did not continue to be enhanced, while a significant T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif (ITIM) domains (TIGIT) abundance increase was observed in the 12th month of infection. Furthermore, increased PD-1 and TIGIT abundance on CD3 + CD8 low T cells was associated with a low CD4 T-cell count (PD-1: r = -0.456, P = 0.043; TIGIT: r = -0.488, P = 0.029) in CHI. Nonetheless, the nonincrease in PD-1 expression on classically activated CD3 + CD8 low T cells was inversely associated with HIV-1 viremia in the first month of AHI ( r = -0.578, P = 0.015). Notably, in the first month of AHI, few CD3 + CD8 low T cells, but comparable amounts of CD3 + CD8 high T cells, responded to Gag peptides. Then, weaker HIV-1-specific T-cell responses were induced in CD3 + CD8 low T cells than CD3 + CD8 high T cells at the 3rd and 12th months of AHI and in CHI.

CONCLUSIONS

Our findings suggest that CD3 + CD8 low T cells play an anti-HIV role in the first month of infection due to their abundance but induce a weak HIV-1-specific immune response. Subsequently, CD3 + CD8 low T-cell number decreased gradually as infection persisted, and their anti-HIV functions were inferior to those of CD3 + CD8 high T cells.

Evaluation of C4b as an adjunct marker in symptomatic RT-PCR negative Covid-19 cases

Introduction

Detecting low viral load has been a challenge in this pandemic, which has led to its escalated transmission. Complement activation has been implicated in pathogenesis of Covid-19 infection. Thus, evaluation of complement activation in suspected Covid-19 infection may help to detect infection and limit false negative cases thus limiting transmission of infection. We speculate that measuring C4b, produced from an activated complement system due to the presence of Covid-19 may help in its detection, even when the viral titers are low.

Methods

Plasma C4b levels of symptomatic RT-PCR positive patients (cases, n = 40); symptomatic RT-PCR negative patients (n = 35) and asymptomatic RT-PCR negative controls (n = 40) were evaluated. Plasma C5b-9, IL-6, D-dimer and C1-Inhibitor (C1-INH) were also measured in cases and controls. ELISA kits were used for all measurements. Statistical analyses were carried out using Stata, version 12 (Stata Corp., Texas, USA).

Results

C4b levels were found to be significantly increased in RT-PCR positive patients as compared to asymptomatic RT-PCR negative controls. RT-PCR negative but symptomatic patients still showed increased C4b levels. The significantly higher levels of C4b in cases with a cut-off value of ≥ 116 ng/ml with optimum sensitivity and specificity of 80% and 52% respectively is indicative of its possible use as an adjunct marker. Increased levels of D-dimer, IL6, along with decreased levels of C1-INH were found in cases compared to controls. Whereas, C5b-9 levels were not significantly raised in cases.

Conclusions

The results of our study suggests that plasma C4b may help to detect infection in false negative cases of RT-PCR that escape detection owing to low viral load. However, to confirm it a large-scale study is needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-022-01033-z.

Elite and posttreatment controllers, two facets of HIV control

PURPOSE OF REVIEW

The quest for HIV-1 cure could take advantage of the study of rare individuals that control viral replication spontaneously (elite controllers) or after an initial course of antiretroviral therapy (posttreatment controllers, PTCs). In this review, we will compare back-to-back the immunological and virological features underlying viral suppression in elite controllers and PTCs, and explore their possible contributions to the HIV-1 cure research.

RECENT FINDINGS

HIV-1 control in elite controllers shows hallmarks of an effective antiviral response, favored by genetic background and possibly associated to residual immune activation. The immune pressure in elite controllers might select against actively transcribing intact proviruses, allowing the persistence of a small and poorly inducible reservoir. Evidence on PTCs is less abundant but preliminary data suggest that antiviral immune responses may be less pronounced. Therefore, these patients may rely on distinct mechanisms, not completely elucidated to date, suppressing HIV-1 transcription and replication.

SUMMARY

PTCs and elite controllers may control HIV replication using distinct pathways, the elucidation of which may contribute to design future interventional strategies aiming to achieve a functional cure.

Changes in NK Cell Subsets and Receptor Expressions in HIV-1 Infected Chronic Patients and HIV Controllers

Natural killer (NK) cells are major effectors of the innate immune response and purported to play an influential role in the spontaneous control of HIV infection. In the present study, we compared the phenotypes of NK cells in the peripheral blood of three groups of subjects with chronic HIV-1 infection, HIV controllers, and healthy donors. The results showed that CD56⁺/CD16^- NK cell subsets decreased in chronic patients and remained unchanged in controllers. Notably, we found that people living with chronic HIV-1 infection had suppressed NKp80, NKp46, and NKG2D expressions on NK cells compared to healthy donors, while HIV controllers remained unchanged. In contrast, NKG2D expression was substantially higher in controllers than in chronic patients (M=97.67, p<0.001). There were no significant differences in inhibitory receptors KIR3DL1 and KIR2DL1 expressions. In addition, plasma cytokine IFN-γ, TNF-α and IL-12showed higher levels in HIV controllers compared to chronic patients. Overall, our study revealed that, as compared to chronic patients, HIV controllers show an increased activating receptors expression and higher number ofCD56⁺/CD16^-NK cell subset, with increased expression levels of plasma cytokines, suggesting that higher immune activation in controllers may have a key role in killing and suppressing HIV.

Analysis of the Characteristics of TIGIT-Expressing CD3-CD56+NK Cells in Controlling Different Stages of HIV-1 Infection

TIGIT expression on natural killer (NK) cells is associated with dysfunction during chronic HIV infection, but the phenotype and biological functions of these cells in the context of acute HIV-1 infection remain poorly understood. Here, 19 acutely infected HIV-1 patients traced at first, third and twelfth month, and age-matched patients with chronic HIV-1 infection were enrolled to investigate the phenotype and functions of TIGIT expression on NK cells. We found that TIGIT-expressing NK cells did not increase in frequency in the first, third and twelfth month of infection until chronic HIV-1 infection lasted over 2 years. The number of TIGIT⁺NK cells in acute infection was positively associated with HIV-1 viral load (r = 0.53, P = 0.0009). CD96 was significantly upregulated on NK cells after acute infection for 1 month and in chronic infection over 2 years, while CD226 was downregulated in chronic infection over 2 years. Further, at different stages of infection, CD96⁻CD226⁺ cells diminished among total NK cells, TIGIT⁺NK and TIGIT⁻NK cells, while CD96⁺CD226⁻ cells expanded. Reduced CD96⁻CD226⁺ cells and elevated CD96⁺CD226⁻ cells among NK cells especially TIGIT⁻NK cells, had opposite associations with viral load in the first month of infection, as well as CD4 T-cell counts in including the twelfth month and more than 2 years of chronic infection. In both HIV-1-infected individuals and healthy donors, TIGIT was predominantly expressed in NKG2A⁻NKG2C⁺NK cells, with a significantly higher proportion than in NKG2A⁺NKG2C⁻NK cells. Moreover, the frequencies of TIGIT⁺NK cells were positively associated with the frequencies of NKG2A⁻NKG2C⁺NK cells in acute infection (r = 0.62, P < 0.0001), chronic infection (r = 0.37, P = 0.023) and healthy donors (r = 0.36, P = 0.020). Enhanced early activation and coexpression of CD38 and HLA-DR in TIGIT⁺NK cells were detected compared to TIGIT⁻NK cells, both of which were inversely associated with the decrease in CD4 T-cell counts in both acute and chronic HIV-1 infection. The ability of TIGIT⁺NK cells to produce TNF-α, IFN-γ and CD107a degranulation substance were consistently weaker than that of TIGIT⁻NK cells in both acute and chronic infection. Moreover, the functionalities of TIGIT⁺NK cells were lower than those of TIGIT⁻NK cells, except for TNF-α⁻CD107a⁺IFN-γ⁻NK cells. These findings highlight the phenotype and functional characteristics of TIGIT-expressing NK cells which have poor capabilities in inhibiting HIV-1 replication and maintaining CD4 T-cell counts.

Factors Associated with Medication Adherence for People Living with Acute HIV Infection in a Tertiary Chinese Hospital in Beijing

Both the management and caregiving intervention of people living with HIV (PLWH), especially during acute HIV-1 infection, represent a public health issue and a form of social support. This current study analyzed the demographic and clinical factors associated with antiretroviral therapy (ART) adherence of PLWH from positive HIV diagnosis to ART initiation in a tertiary Chinese hospital in Beijing. A total of 200 participants diagnosed with acute HIV-1 infection were enrolled in this study. We collected demographic and clinical data by the use of a self-reported questionnaire. Bivariate and multivariate logistic regressions were used to determine associations between potential variables and outcomes. We found that medication adherence was impacted by years of ART and number of reminders (all P < 0.05). In addition, medication adherence was associated with viral load at 48 weeks (P = 0.035). Future studies are needed to investigate effective interventions that could facilitate ART adherence.

A Pilot Study of the Humoral Response Against the AntiSense Protein (ASP) in HIV-1-Infected Patients

The existence of an antisense Open Reading Frame (ORF) that encodes a putative AntiSense Protein (ASP) on the proviral genome of Human Immunodeficiency Virus type 1 (HIV-1) was a source of debate for 30 years. During the last years, some progresses have been made to characterize the cellular immune response against ASP in HIV-1 seropositive patients. However, no tools were available for the detection of antibodies to ASP in the plasma of HIV-1-infected patients during the natural course of the infection. The aim of our study was to develop a Luciferase Immuno-Precipitation System (LIPS) to monitor the quantitative detection of ASP-specific antibodies in the plasma of HIV-1-infected patients [antiretroviral therapy (ART) naive-patients, patients under ART and HIV-1 controllers], patients who discontinued antiretroviral drugs (ARV). We further used this approach to delineate the epitopes of ASP targeted by antibodies. Antibodies directed against ASP were detected in 3 out of 19 patients who discontinued ARV (15%) and in 1 out of 10 ART-naive patients (10%), but were neither detected in HIV-1 infected patients under ART nor in HIV-1 controllers. Individual variations in levels of ASP-specific antibodies were detected overtime. Both the conserved prolin-rich motif and the core 60–189 region of ASP were found to be essential for antibody recognition in the four patients tested positive for anti-ASP antibodies, who were all untreated at the time of sampling. Moreover, for two of these patients, increased levels of ASP-specific antibodies were observed concomitantly to viremia declines. Overall, our method may represent a useful tool to detect a humoral response to ASP in HIV-1-infected patients, which allowed us to confirm the expression of ASP during the course of HIV-1 infection. Further studies will be needed to fully characterize the humoral response to ASP in HIV-1-infected patients.

Increasing contribution of integrated forms to total HIV DNA in blood during HIV disease progression from primary infection

BACKGROUND

In the current context of research on HIV reservoirs, offering new insights into the persistence of HIV DNA in infected cells, which prevents viral eradication, may aid in identifying cure strategies. This study aimed to describe the establishment of stable integrated forms among total HIV DNA during primary infection (PHI) and their dynamics during the natural history of infection.

METHODS

Total and integrated HIV DNA were quantified in blood from 74 PHI patients and 97 recent seroconverters (<12 months following infection, "progression cohort"). The evolution of both markers over six years was modelled (mixed-effect linear models). Their predictive values for disease progression were studied (Cox models).

FINDINGS

For most patients during PHI, stable integrated forms were a minority among total HIV DNA (median: 12%) and became predominant thereafter (median at AIDS stage: 100%). Both total and integrated HIV DNA increased over a six-year period. Patients from the progression cohort who reached clinical AIDS during follow-up (n = 34) exhibited higher total and integrated HIV DNA levels at seroconversion and a higher percentage of integrated forms than did slower progressors (n = 63) (median: 100% vs 44%). The integrated HIV DNA load was strongly associated with the risk of developing AIDS (aRR = 2.63, p = 0.002).

INTERPRETATION

The profile of "rapid" or "slower" progression in the natural history of HIV infection appears to be determined early in the course of HIV infection. The strong predominance of unstable unintegrated forms in PHI may explain the great benefit of this early treatment, which induces a sharp decrease in total HIV DNA. FUND: French National Agency for Research on AIDS and Viral Hepatitis.

Natural selection for killer receptors and their MHC class I ligands: In pursuit of gene pairs that fit well in tandem

Our understanding of the genetic basis of host resistance to viral infection and disease has progressed significantly over the last century. Numerous genes coding for modifiers of immune functions have been identified, which impact a variety of critical cellular processes, including signaling via lymphocyte receptors and their ligands, signal transduction, cytokine signaling, production and release of cytotoxic effectors, transcriptional regulation, and proliferation. Genome-wide association studies implicate an important role for both highly polymorphic NK cell receptors and their MHC class I ligands in modifying host resistance. These findings indicate NK cells are critical mediators of viral control with considerable potential to affect morbidity and mortality outcomes. They further suggest that both stimulatory and inhibitory NK receptor polymorphisms alter NK cell sensing of MHC I ligands on viral targets, which influences how NK cells respond to infection. In many cases, however, the underlying causes associated with host outcomes remain elusive. Herein, we discuss several modes of NK cell sensing of MHC I and MHC I-like molecules on viral targets, and the role of genetic diversity in this evolutionarily dynamic process. We further suggest that natural selection for paired NK receptors with opposing function, but shared MHC I ligands may give rise to rare, but highly effective MHC I-dependent modes of NK cell sensing of viral targets.

Association of Diverse Genotypes and Phenotypes of Immune Cells and Immunoglobulins With the Course of HIV-1 Infection

Disease progression among HIV-1-infected individuals varies widely, but the mechanisms underlying this variability remains unknown. Distinct disease outcomes are the consequences of many factors working in concert, including innate and adaptive immune responses, cell-mediated and humoral immunity, and both genetic and phenotypic factors. Current data suggest that these multifaceted aspects in infected individuals should be considered as a whole, rather than as separate unique elements, and that analyses must be performed in greater detail in order to meet the requirements of personalized medicine and guide optimal vaccine design. However, the wide adoption of antiretroviral therapy (ART) influences the implementation of systematic analyses of the HIV-1-infected population. Consequently, fewer data will be available for acquisition in the future, preventing the comprehensive investigations required to elucidate the underpinnings of variability in disease outcome. This review seeks to recapitulate the distinct genotypic and phenotypic features of the immune system, focusing in particular on comparing the surface proteins of immune cells among individuals with different HIV infection outcomes.

Clinical features of acute human immunodeficiency virus infection in Taiwan: A multicenter study

BACKGROUND/PURPOSE

Acute HIV infection is characterized by a high concentration of HIV RNA in the plasma and rapid depletion of the CD4 cell count. This multicenter, retrospective observational study aimed to characterize the manifestations of acuteHIV infection in Taiwan.

METHODS

Between 1 January 2012 and 31 December 2016, all patients aged 20 years or greater who presented with acute HIV infection were included. Demographic and clinical characteristics of the patients at diagnosis were collected. Baseline laboratory assessment included hemogram, CD4 count, plasma HIV RNA load (PVL), serologic markers of syphilis and hepatitis A, B, and C viruses, and serum biochemistry.

RESULTS

The proportion of acute HIV infection was 6.9% among the patients with newly diagnosed HIV infection during the study period. The most common presenting symptoms of acute HIV infection were fever, fatigue, and myalgia. The median PVL at diagnosis was 5.9 log₁₀ copies/ml, and median CD4 count was 307 cells/mm³. A total of 68 patients (27%) had baseline CD4 count less than 200 cells/mm³. Multiple logistic regression analysis, showed that the baseline CD4 count (OR, 4.02; p = 0.013) and aspartate aminotransaminase levels (OR, 3.49; p = 0.002) were associated with high PVL (>5 log₁₀ copies/ml); and high baseline PVL (OR, 2.64; p = 0.002) was associated with symptomatic acute HIV infection.

CONCLUSIONS

Manifestations of acute HIV infection are nonspecific and of wide spectrum ranging from fever to severe illness. A higher proportion of patients with initial CD4 counts of 200 cells/mm³ or less during acute HIV infection warrants early, timely diagnosis and treatment to prevent rapid disease progression.

Plasma Levels of Complement Factor I and C4b Peptides Are Associated with HIV Suppression

Individuals who exhibit long-term HIV suppression and CD4 T-cell preservation without antiretroviral therapy are of great interest for HIV research. There is currently no robust method for rapid identification of these “HIV controller” subjects; however, HLA-B*57 (human leukocyte antigen (major histocompatibility complex), class I, B*57) genotype exhibits modest sensitivity for this phenotype. Complement C3b and C4b can influence HIV infection and replication, but studies have not examined their possible link to HIV controller status. We analyzed HLA-B*57 genotype and complement levels in HIV-positive patients receiving suppressive antiretroviral therapy, untreated HIV controllers, and HIV-negative subjects to identify factors associated with HIV controller status. Our results revealed that the plasma levels of three C4b-derived peptides and complement factor I outperformed all other assayed biomarkers for HIV controller identification, although we could not analyze the predictive value of biomarker combinations with the current sample size. We believe this rapid screening approach may prove useful for improved identification of HIV controllers.

Syphilis Infection Differentially Regulates the Phenotype and Function of γδ T Cells in HIV-1-Infected Patients Depends on the HIV-1 Disease Stage

A rapidly escalating outbreak of syphilis infection has been affected men who have sex with men, particularly those with HIV-1 infection. γδ T cells are unconventional immune cells with two main subsets, Vδ1 T cells and Vδ2 T cells, which possess a combination of innate and adaptive immune features allowing them against HIV-1. However, whether syphilis infection affects the phenotype and function of γδ T cells in HIV-1-infected patients remains unclear, especially in acute HIV-1 infection (AHI). In this study, we enrolled 57 HIV-1-infected patients (24 with HIV-1 infection only and 33 coinfected with syphilis) from an acute HIV-1-infected cohort in Beijing (PRIMO). A comprehensive analysis of γδ T-cell phenotype and function was performed by flow cytometry. We found syphilis coinfection could reverse the imbalance of Vδ1/Vδ2 ratio in AHI. Syphilis infection results in decreased γδ T-cell activation in AHI, but increased γδ T-cell activation in chronic HIV-1 infection (CHI). Moreover, patients with CHI had larger numbers of IL-17-producing γδ T cells than those with AHI, regardless of syphilis status. Thus, syphilis affected the γδ T-cell immune response differently in patients depending on the stages of HIV-1 disease. In addition, the percentage of IL-17-producing γδ T cells was positively correlated with the percentage of neutrophils. These results suggest that the γδ T-cell/IL-17/neutrophil axis is involved in HIV-1 pathogenesis and disease progression. Taken together, our observations provide new insight into the roles of γδ T cells in immunopathogenesis of syphilis and HIV-1 coinfection, particularly during AHI, and our findings may be helpful for the prevention of syphilis and other sexually transmitted infections and highlight the great significance on the remedy of patients coinfected with HIV-1.

Demographics and natural history of HIV-1-infected spontaneous controllers of viremia

OBJECTIVES

HIV-1-infected persons spontaneously controlling viremia without treatment (SCV) are rare. Sex and race effects on prevalence and outcome are poorly defined, and it is unclear whether SCV qualitatively or quantitatively differs from typical infection. These issues are examined in this article.

DESIGN

Medical records of 46 524 persons receiving outpatient care for HIV-1 infection were reviewed. Of these, 29 811 had adequate viremia testing for SCV screening.

METHODS

SCV was defined as at least three consecutive plasma viremia measurements <50 RNA copies/ml spanning at least 1 year without treatment. SCV loss was defined as at least three consecutive viremia measurements ≥50 RNA copies/ml or one ≥1000 RNA copies/ml. Demographics of persons with SCV were compared with the total population. Viremia and blood CD4 T-cell levels during SCV were compared between demographic subgroups and persons who maintained or lost SCV during observation.

RESULTS

In total, 53 persons (0.18%) met SCV criteria. Prevalence was higher for women versus men and blacks versus whites; these appeared independent. Loss of SCV was observed at 1.22% per year, and significantly associated with viremia 'blips'. Blip magnitudes fit log-normal distributions with means below 50 RNA copies/ml.

CONCLUSION

Our novel observation of higher SCV prevalence in women and blacks is consistent with prior studies of typical chronic infection. Viremia blips correspond to greater risk of loss of SCV, likely reflecting higher set-point viremia under the limit of detection. Our findings suggest that SCV represents an extreme along a continuum of HIV-1 infection, and not qualitative difference.

Impact of CD4 and CD8 dynamics and viral rebounds on loss of virological control in HIV controllers

Objective

HIV controllers (HICs) spontaneously maintain HIV viral replication at low level without antiretroviral therapy (ART), a small number of whom will eventually lose this ability to control HIV viremia. The objective was to identify factors associated with loss of virological control.

Methods

HICs were identified in COHERE on the basis of ≥5 consecutive viral loads (VL) ≤500 copies/mL over ≥1 year whilst ART-naive, with the last VL ≤500 copies/mL measured ≥5 years after HIV diagnosis. Loss of virological control was defined as 2 consecutive VL >2000 copies/mL. Duration of HIV control was described using cumulative incidence method, considering loss of virological control, ART initiation and death during virological control as competing outcomes. Factors associated with loss of virological control were identified using Cox models. CD4 and CD8 dynamics were described using mixed-effect linear models.

Results

We identified 1067 HICs; 86 lost virological control, 293 initiated ART, and 13 died during virological control. Six years after confirmation of HIC status, the probability of losing virological control, initiating ART and dying were 13%, 37%, and 2%. Current lower CD4/CD8 ratio and a history of transient viral rebounds were associated with an increased risk of losing virological control. CD4 declined and CD8 increased before loss of virological control, and before viral rebounds.

Discussion

Expansion of CD8 and decline of CD4 during HIV control may result from repeated low-level viremia. Our findings suggest that in addition to superinfection, other mechanisms, such as low grade viral replication, can lead to loss of virological control in HICs.

Treatment interruption in chronically HIV-infected patients with an ultralow HIV reservoir

OBJECTIVES

To investigate the potential for combination antiretroviral therapy (cART)-free remission following analytic treatment interruption (ATI) in chronically HIV-infected patients with ultralow cell-associated DNA.

METHODS

Pilot study of patients (pts) with plasma viral load (pVL) less than 50 copies/ml for more than 2 years on cART, CD4 above 500 cells/μl, CD4/CD8 above 0.9, CD4 nadir above 300 cells/μl and HIV-DNA below 100 copies/10 peripheral blood mononuclear cells (PBMCs), undergoing treatment interruption. Ultrasensitive pVL, CD4 cell count, triplicate HIV-DNA were measured at D0, W2, W4, and every 4 weeks off-ART until W48 and at W4, W12 and W24 after ART resumption (RxR). RxR occurred in case of pVL rebound above 400 copies/ml or CD4 above 400 cells or HIV-related clinical event. The primary endpoint was the percentage of patients who did not reach RxR criteria at W24. Individuals were to be enrolled in three cohorts of five. Enrolment in cohort 2 began if at least one of five patients from cohort 1 remained in success at W8. Cohort 3 did not start.

RESULTS

Ten patients were enrolled, with median (range) CD4 1118 cells/μl (608-1494), CD4/CD8 2.1 (1.4-2.6), HIV-DNA 66 copies/10 PBMC (<66-66) at screening, viral suppression of 4.9 years (2.9-8.3), CD4 nadir 495 cells/μl (330-739). One patient remained off-ART up to W48. Viral rebound occurred in nine of 10 patients at W2 (2 patients), W4 (6 patients) and W12 (one patient). pVL was resuppressed on cART at W4 (8 patients) and W12 (one patient). HIV DNA returned to baseline values within a median of 12 weeks following RxR.

CONCLUSION

In a highly selected population of 10 patients with chronic HIV infection, an excellent immune status, durable virological suppression and ultralow reservoir, the success rate of ATI was 10% (95% confidence interval 0.3-44.5%) and nine of 10 patients had prompt rebound of plasma viremia. Resumption of ART led to return to baseline cell-associated total DNA.

Host genetic factors associated with symptomatic primary HIV infection and disease progression among Argentinean seroconverters

BACKGROUND

Variants in HIV-coreceptor C-C chemokine receptor type 5 (CCR5) and Human leukocyte antigen (HLA) genes are the most important host genetic factors associated with HIV infection and disease progression. Our aim was to analyze the association of these genetic factors in the presence of clinical symptoms during Primary HIV Infection (PHI) and disease progression within the first year.

METHODS

Seventy subjects diagnosed during PHI were studied (55 symptomatic and 15 asymptomatic). Viral load (VL) and CD4 T-cell count were evaluated. HIV progression was defined by presence of B or C events and/or CD4 T-cell counts <350 cell/mm3. CCR5 haplotypes were characterized by polymerase chain reaction and SDM-PCR-RFLP. HLA-I characterization was performed by Sequencing.

RESULTS

Symptoms during PHI were significantly associated with lower frequency of CCR5-CF1 (1.8% vs. 26.7%, p = 0.006). Rapid progression was significantly associated with higher frequency of CCR5-CF2 (16.7% vs. 0%, p = 0.024) and HLA-A*11 (16.7% vs. 1.2%, p = 0.003) and lower frequency of HLA-C*3 (2.8% vs. 17.5%, p = 0.035). Higher baseline VL was significantly associated with presence of HLA-A*11, HLA-A*24, and absence of HLA-A*31 and HLA-B*57. Higher 6-month VL was significantly associated with presence of CCR5-HHE, HLA-A*24, HLA-B*53, and absence of HLA-A*31 and CCR5-CF1. Lower baseline CD4 T-cell count was significantly associated with presence of HLA-A*24/*33, HLA-B*53, CCR5-CF2 and absence of HLA-A*01/*23 and CCR5-HHA. Lower 6-month CD4 T-cell count was associated with presence of HLA-A*24 and HLA-B*53, and absence of HLA-A*01 and HLA-B*07/*39. Moreover, lower 12-month CD4 T-cell count was significantly associated with presence of HLA-A*33, HLA-B*14, HLA-C*08, CCR5-CF2, and absence of HLA-B*07 and HLA-C*07.

CONCLUSION

Several host factors were significantly associated with disease progression in PHI subjects. Most results agree with previous studies performed in other groups. However, some genetic factor associations are being described for the first time, highlighting the importance of genetic studies at a local level.

Distortion of memory Vδ2 γδ T cells contributes to immune dysfunction in chronic HIV infection

γδ T cells play important roles in innate immunity as the first-line of defense against infectious diseases. Human immunodeficiency virus (HIV) infection disrupts the balance between Vδ(1) T cells and Vδ(2) T cells and causes dysfunction among γδ T cells. However, the biological mechanisms and clinical consequences of this disruption require further investigation. In this study, we performed a comprehensive analysis of phenotype and function of memory γδ T cells in cohorts of Chinese individuals with HIV infection. We found a dynamic change in memory Vδ(2) γδ T cells, skewed toward an activated and terminally differentiated effector memory phenotype T(EMRA) Vδ(2) γδ T cell, which may account for the dysfunction of Vδ(2) γδ T cells in HIV disease. In addition, we found that IL-17-producing γδ T cells were significantly increased in HIV-infected patients with fast disease progression and positively correlated with HLA-DR(+) γδ T cells and CD38(+)HLA-DR(+) γδ T cells. This suggests the IL-17 signaling pathway is involved in γδ T-cell activation and HIV pathogenesis. Our findings provide novel insights into the role of Vδ(2) T cells during HIV pathogenesis and represent a sound basis on which to consider immune therapies with these cells.

HIV "elite controllers" are characterized by a high frequency of memory CD8+ CD73+ T cells involved in the antigen-specific CD8+ T-cell response

Human immunodeficiency virus type 1 (HIV-1) infection is characterized by chronic immune activation and suppressed T-lymphocyte functions. Here we report that CD73, both a coactivator molecule of T cells and an immunosuppressive ecto-enzyme through adenosine production, is only weakly expressed by CD8+ T cells of HIV-infected patients and only partially restored after successful antiviral treatment. CD73 expression on CD8+ T cells correlates inversely with cell activation both ex vivo and in vitro. However, CD8+ T cells from HIV controllers (HICs), which spontaneously control HIV replication, express CD73 strongly, despite residual immune activation. Finally, we demonstrate that CD73 is involved in the HIV-specific CD8+ T-cell expansion. Thus, we show that CD73 is central to the functionality of HIV-specific CD8+ T cells and that the preservation of HIV-specific CD73+ CD8+ T cells is a characteristic of HICs. These observations reveal a novel mechanism involved in the control of viral replication.

Evidence for innate immune system activation in HIV type 1-infected elite controllers

BACKGROUND

Elite controllers maintain high CD4(+) T-cell counts and suppress plasma human immunodeficiency virus (HIV) viremia in the absence of antiretroviral therapy (ART). It is unclear whether levels of biomarkers associated with coagulation, monocyte activation, and inflammation, which are linked to HIV-associated mortality, differ among elite controllers, ART recipients with suppressed viremia (plasma HIV type 1 RNA load, <50 copies/mL), and HIV-negative controls.

METHODS

A total of 68 elite controllers, 68 ART recipients with suppressed viremia, and 35 HIV-negative participants were evaluated. Levels of biomarkers in cryopreserved plasma were measured by enzyme-linked immunosorbent assay and electrochemiluminescence-based assay. Cryopreserved peripheral blood mononuclear cells were used to assess monocyte phenotype and function and interferon-inducible gene expression (IFIG). Nonparametric testing was used to compare median values among groups.

RESULTS

CD4(+) T-cell counts were similar between elite controllers and HIV-negative controls but significantly lower in ART recipients with suppressed viremia. Levels of C-reactive protein and interleukin 6 were higher and IFIG upregulated in both HIV-positive groups, compared with HIV-negative controls. D-dimer and soluble tissue factor levels were significantly elevated in elite controllers, compared with those in ART recipients with suppressed viremia and HIV-negative controls (P < .01). Monocytes from elite controllers (and ART recipients with suppressed viremia) expressed lower CCR2 and higher CX3CR1 levels than monocytes from HIV-negative controls. In addition, elite controllers had a significantly higher proportion of CD14(++)CD16(+) monocytes, compared with HIV-negative controls.

CONCLUSION

Elite controllers maintain control of plasma HIV viremia and have evidence of an activated innate immune response.

Prospective antiretroviral treatment of asymptomatic, HIV-1 infected controllers

The study of HIV-infected "controllers" who are able to maintain low levels of plasma HIV RNA in the absence of antiretroviral therapy (ART) may provide insights for HIV cure and vaccine strategies. Despite maintaining very low levels of plasma viremia, controllers have elevated immune activation and accelerated atherosclerosis. However, the degree to which low-level replication contributes to these phenomena is not known. Sixteen asymptomatic controllers were prospectively treated with ART for 24 weeks. Controllers had a statistically significant decrease in ultrasensitive plasma and rectal HIV RNA levels with ART. Markers of T cell activation/dysfunction in blood and gut mucosa also decreased substantially with ART. Similar reductions were observed in the subset of "elite" controllers with pre-ART plasma HIV RNA levels below conventional assays (<40 copies/mL). These data confirm that HIV replication persists in controllers and contributes to a chronic inflammatory state. ART should be considered for these individuals (ClinicalTrials.gov NCT01025427).

Comparison of HIV DNA and RNA in gut-associated lymphoid tissue of HIV-infected controllers and noncontrollers

OBJECTIVES

HIV-infected controllers have provided novel insights into mechanisms of viral control. We investigated the degree to which HIV DNA and RNA are present in gut-associated lymphoid tissue (GALT) of controllers.

DESIGN

Cross-sectional cohort study.

METHODS

Colorectal biopsy pieces were obtained from five untreated noncontrollers, five ART-suppressed patients, and nine untreated controllers.

RESULTS

Rectal HIV DNA was lower in controllers (median 496 copies/10(6) CD4 T cells) than in untreated noncontrollers (117483 copies/10(6) CD4+ T cells, P = 0.001) and ART-suppressed patients (6116 copies/10(6) CD4 T cells, P = 0.004). Similarly, rectal HIV RNA was lower in controllers (19 copies/10(6) CD4 T cells) than in noncontrollers (15210 copies/10(6) CD4+ T cells, P = 0.001) and ART-suppressed patients (1625 copies/10(6) CD4+ T cells, P = 0.0599). Rectal HIV RNA/DNA ratios were not statistically different between the three groups.

CONCLUSION

Despite being able to maintain very low plasma HIV RNA levels in the absence of antiretroviral therapy (ART), HIV-infected controllers have readily measurable levels of HIV DNA and RNA in GALT. As expected, controllers had lower rectal HIV DNA and RNA compared with untreated noncontrollers and ART-suppressed individuals. Compared with the mechanisms of 'natural' viral control of controllers, long-term ART does not reduce the total HIV reservoir to the level of controllers.

Gag-positive reservoir cells are susceptible to HIV-specific cytotoxic T lymphocyte mediated clearance in vitro and can be detected in vivo [corrected]

Resting CD4+ T cells infected with HIV persist in the presence of suppressive anti-viral therapy (ART) and are barriers to a cure. One potential curative approach, therapeutic vaccination, is fueled by recognition of the ability of a subset of elite controllers (EC) to control virus without therapy due to robust anti-HIV immune responses. Controllers have low levels of integrated HIV DNA and low levels of replication competent virus, suggesting a small reservoir. As our recent data indicates some reservoir cells can produce HIV proteins (termed GPR cells for Gag-positive reservoir cells), we hypothesized that a fraction of HIV-expressing resting CD4+ T cells could be efficiently targeted and cleared in individuals who control HIV via anti-HIV cytotoxic T lymphocytes (CTL). To test this we examined if superinfected resting CD4+ T cells from EC express HIV Gag without producing infectious virus and the susceptibility of these cells to CTL. We found that resting CD4+ T cells expressed HIV Gag and were cleared by autologous CD8+ T cells from EC. Importantly, we found the extent of CTL clearance in our in vitro assay correlates with in vivo reservoir size and that a population of Gag expressing resting CD4+ T cells exists in vivo in patients well controlled on therapy.

MHC-driven HIV-1 control on the long run is not systematically determined at early times post-HIV-1 infection

INTRODUCTION

Human leukocyte antigen (HLA) class I-driven long-term protection against HIV-1 is mainly associated with HLA-B*27 and HLA-B*57. This effect is observed early after infection. Clarification needs to be established concerning the moment of action for the other HLA-B or HLA-C alleles.

METHODS

HLA-B and HLA-C alleles from 111 individuals that control HIV-1 disease for over 8 years and from 747 seroconverters frequencies were compared. Also, HLA-B and HLA-C influence on early levels of plasma HIV-RNA, cellular HIV-DNA, CD4, CD8 and CD4/CD8 ratio was evaluated among the seroconverters. We performed univariate, multivariate and haplotypic analyses in order to disentangle the respective contribution of the HLA-B and HLA-C genes.

RESULTS

The haplotypes analysis shows three patterns of protective effects of HLA-B and HLA-C alleles or haplotypes. First, the HLA B*57, HLA-B*27, HLA-B*13 and HLA-C*14 alleles, which have a strong effect on long-term disease control, also influence at least one of the early infection phenotypes. Second, HLA-B*52 has a strong effect during early time points on HIV-RNA without significant effect on the long-term control of HIV-1. Finally, the HLA-B*14-C*08 haplotype has a strong effect on the long-term protection, without influencing early viral control.

CONCLUSION

Our study highlighted independent effects of HLA-B and HLA-C alleles on HIV-disease progression. Furthermore, some alleles appeared to be specifically associated with either long-term control or early virological parameters, suggesting different immunological mechanisms according to the disease stages.

Evidence for a continuous drift of the HIV-1 species towards higher resistance to neutralizing antibodies over the course of the epidemic

We compared the neutralization sensitivity of early/transmitted HIV-1 variants from patients infected by subtype B viruses at 3 periods of the epidemic (1987–1991, 1996–2000, 2006–2010). Infectious pseudotyped viruses expressing envelope glycoproteins representative of the viral quasi-species infecting each patient were tested for sensitivity to neutralization by pools of sera from HIV-1 chronically infected patients and by an updated panel of 13 human monoclonal neutralizing antibodies (HuMoNAbs). A progressive significantly enhanced resistance to neutralization was observed over calendar time, by both human sera and most of the HuMoNAbs tested (b12, VRC01, VRC03, NIH45-46^G54W, PG9, PG16, PGT121, PGT128, PGT145). Despite this evolution, a combination of two HuMoNAbs (NIH45-46^G54W and PGT128) still would efficiently neutralize the most contemporary transmitted variants. In addition, we observed a significant reduction of the heterologous neutralizing activity of sera from individuals infected most recently (2003–2007) compared to patients infected earlier (1987–1991), suggesting that the increasing resistance of the HIV species to neutralization over time coincided with a decreased immunogenicity. These data provide evidence for an ongoing adaptation of the HIV-1 species to the humoral immunity of the human population, which may add an additional obstacle to the design of an efficient HIV-1 vaccine.

Most of the patients develop autologous neutralizing antibodies (NAbs) during HIV-1 infection. These NAbs drive the viral evolution and lead to the selection of escape variants at the individual level. The aim of our study was to check if, subsequently to the selective pressure exerted by the individual NAbs responses, the HIV-1 species has evolved at the population level towards an enhanced resistance to antibody neutralization. By comparing HIV-1 subtype B variants collected at three periods spanning more than 2 decades, we found a significantly progressive enhanced resistance to neutralization of the HIV-1 species over time. In addition, the enhanced resistance of the HIV species to neutralization coincided with a decreased capability of the virus to induce NAbs in infected patients. Despite this evolution, one combination of two human monoclonal broadly NAbs still were able to neutralize the most recent HIV-1 variants, suggesting that this combination should be preferentially included in future human immunoprophylaxis trials.

HLA-B*44 is associated with a lower viral set point and slow CD4 decline in a cohort of Chinese homosexual men acutely infected with HIV-1

HLA class I alleles have been shown to have differential impacts on the viral load and the outcome of HIV-1 disease progression. In this study, HLA class I types from residents of China with acute HIV-1 infection, diagnosed between 2006 and 2011, were identified and the association between expression of individual HLA alleles and the level of the set point viral load was analyzed. A lower level of set point viral load was found to be associated with the Bw4 homozygote on HLA-B alleles. B*44 and B*57 alleles have also been found to be associated with lower set point viral load. The set point viral load of B*44-positive individuals homozygous for Bw4 was significantly lower than that of B*44-negative individuals homozygous for Bw4 (P = 0.030). The CD4 count declined to <350 in fewer B*44-positive individuals than B*44-negative individuals (X(2) = 7.295, P = 0.026). B*44-positive individuals had a lower magnitude of p24 pool-specific T cell responses than B*44-negative individuals homozygous for Bw4, though this was not statistically significant. The p24 pool-specific T cell responses were also inversely correlated with lower viral load (rs = -0.88, P = 0.033). Six peptides within p24 were recognized to induce the specific-T cell response in B*44-positive individuals, and the peptide breadth of response was same as that in B*44-negative individuals homozygous for Bw4, but the median magnitude of specific-T cell responses to the recognized peptides in B*44-positive individuals was lower than that in B*44-negative individuals homozygous for Bw4 (P = 0.049). These findings imply that weak p24-specific CD8(+) T cell responses might play an important role in the control of HIV viremia in B*44 allele-positive individuals. Such studies might contribute to the development of future therapeutic strategies that take into account the genetic background of the patients.

Recommendations for the follow-up of study participants with breakthrough HIV infections during HIV/AIDS biomedical prevention studies

OBJECTIVE

To facilitate collection of cumulative data on longitudinal HIV disease outcomes during HIV prevention studies by developing recommendations for follow-up of the relatively few study participants with breakthrough infections.

DESIGN

We formed a working group to compare and contrast the various approaches taken in recent HIV prevention trials, to summarize the advantages and disadvantages associated with each, and to explore the feasibility of developing protocols for the long-term follow-up of seroconverters.

METHODS

We reviewed study designs, objectives, and assessments in 15 interventional studies that followed HIV seroconverters. Protocol team members joined discussions of the various approaches and developed recommendations.

RESULTS

Most HIV prevention clinical trials share a core set of objectives, including the description/comparison of virological, immunological, and clinical course of HIV, and sometimes a comparison of preseroconversion and postseroconversion behavior. Long-term follow-up of seroconverters can be conducted in separate studies if the transition from parent protocol is effectively managed.

CONCLUSION

We recommend the development of harmonized seroconverter protocols. Although specific research questions in the postseroconversion period may differ depending on prevention modality, harmonizing key evaluations would create an opportunity to ask overarching questions that inform the prevention field with respect to design and implementation of future combination prevention studies. Follow-up immediately postseroconversion should be conducted in the parent protocol before roll over into a follow-up protocol. Development of specimen repositories with ample volumes for future assays, standardized definitions of infection, diagnosis and seroconversion dates, and harmonization of study objectives and sample collections at key time points are important.

Single-copy assay quantification of HIV-1 RNA in paired cerebrospinal fluid and plasma samples from elite controllers

OBJECTIVE

Elite controllers are a rare subset of HIV-1-infected individuals who maintain HIV-1 RNA concentrations in plasma below the lower limit of quantification of clinical assays (<20-50 copies/ml) in the absence of antiretroviral therapy. Here, we examine to what extent elite controllers also control infection of the central nervous system (CNS).

DESIGN

We analysed paired cerebrospinal fluid (CSF) and plasma samples using a highly sensitive assay for HIV-1 RNA quantification.

METHODS

We analysed 28 CSF samples and 27 concurrent plasma samples from 14 elite controllers with the highly sensitive single-copy assay (SCA) that allows for HIV-1 RNA quantification down to less than one copy of HIV-1 RNA per millilitre.

RESULTS

Three samples were excluded because of internal standard failure. HIV-1 RNA was detected in only five of 26 CSF samples compared with 14 of 26 plasma samples (P = 0.02), with a median of 0.2 (range, 0.1-6) copies/ml in CSF compared with 0.8 (range, 0.1-189 copies/ml) in plasma (P < 0.0001).

CONCLUSION

HIV-1 RNA could not be detected in CSF in most elite controllers using the highly sensitive SCA, and when detected, it was at significantly lower frequencies and concentrations than in plasma. Elite controllers thus control HIV-1 in the CNS very well. Whether the infrequent and small amounts of HIV-1 RNA in the CSF reflect production from a local reservoir or virion exchange between the blood and the CSF is uncertain.

Precise determination of time to reach viral load set point after acute HIV-1 infection

OBJECTIVE

The HIV viral load set point has long been used as a prognostic marker of disease progression and more recently as an end-point parameter in HIV vaccine clinical trials. The definition of set point, however, is variable. Moreover, the earliest time at which the set point is reached after the onset of infection has never been clearly defined.

METHODS

In this study, we obtained sequential plasma viral load data from 60 acutely HIV-infected Chinese patients among a cohort of men who have sex with men, mathematically determined viral load set point levels, and estimated time to attain set point after infection. We also compared the results derived from our models and that obtained from an empirical method.

RESULTS

With novel uncomplicated mathematic model, we discovered that set points may vary from 21 to 119 days dependent on the patients' initial viral load trajectory. The viral load set points were 4.28 ± 0.86 and 4.25 ± 0.87 log10 copies per milliliter (P = 0.08), respectively, as determined by our model and an empirical method, suggesting an excellent agreement between the old and new methods.

CONCLUSIONS

We provide a novel method to estimate viral load set point at the very early stage of HIV infection. Application of this model can accurately and reliably determine the set point, thus providing a new tool for physicians to better monitor early intervention strategies in acutely infected patients and scientists to rationally design preventative vaccine studies.

HIV-1 Vaccine Trials: Evolving Concepts and Designs

An effective prophylactic HIV-1 vaccine is needed to eradicate the HIV/AIDS pandemic but designing such a vaccine is a challenge. Despite many advances in vaccine technology and approaches to generate both humoral and cellular immune responses, major phase-II and -III vaccine trials against HIV/AIDS have resulted in only moderate successes. The modest achievement of the phase-III RV144 prime-boost trial in Thailand re-emphasized the importance of generating robust humoral and cellular responses against HIV. While antibody-directed approaches are being pursued by some groups, others are attempting to develop vaccines targeting cell-mediated immunity, since evidence show CTLs to be important for the control of HIV replication. Phase-I and -IIa multi-epitope vaccine trials have already been conducted with vaccine immunogens consisting of known CTL epitopes conserved across HIV subtypes, but have so far fallen short of inducing robust and consistent anti-HIV CTL responses. The concepts leading to the development of T-cell epitope-based vaccines, the outcomes of related clinical vaccine trials and efforts to enhance the immunogenicity of cell-mediated approaches are summarized in this review. Moreover, we describe a novel approach based on the identification of SIV and FIV antigens which contain conserved HIV-specific T-cell epitopes and represent an alternative method for developing an effective HIV vaccine against global HIV isolates.

HIV-1 dynamics: a reappraisal of host and viral factors, as well as methodological issues

The dynamics of HIV-1 viremia is a complex and evolving landscape with clinical and epidemiological (public health) implications. Most studies have relied on the use of set-point viral load (VL) as a readily available proxy of viral dynamics to assess host and viral correlates. This review highlights recent findings from population-based studies of set-point VL, focusing primarily on robust data related to host genetics. A comprehensive understanding of viral dynamics will clearly need to consider both host and viral characteristics, with close attention to (i) the timing of VL measurements, (ii) the biology of viral evolution, (iii) compartments of active viral replication, (iv) the transmission source partner as the immediate past microenvironment, and (v) proper application of statistical models.

Impact of protective killer inhibitory receptor/human leukocyte antigen genotypes on natural killer cell and T-cell function in HIV-1-infected controllers

OBJECTIVE

Both protective T-cell genotypes and natural killer (NK) cell genotypes have been associated with delayed progression to AIDS and shown to be co-inherited in HIV-1-infected individuals who limit viral replication in absence of antiretroviral therapy ('controllers'). However, a comparative analysis of the genotype and function of the innate and adaptive immune compartments in HIV-1-infected controller individuals has been understudied to date.

DESIGN

Here, we simultaneously tested NK and T-cell function in controllers to investigate the mechanism(s) that might account for host immune control over viral replication.

METHODS

We measured CD8 T-cell responses against HIV-1 utilizing overlapping 15-mer peptides spanning the HIV-1 consensus clade B Gag protein and tested NK cell degranulation and cytokine secretion against tumor target cells following interferon-α (IFNα) stimulation.

RESULTS

Among a cohort of 37 controllers, the presence of protective major histocompatibility complex class I human leukocyte antigen (HLA) alleles (such as HLA-B*57) was not correlated with HIV-specific CD8 responses. In contrast, the inheritance of a protective killer inhibitory receptor KIR3DL1*h/*y receptor genotype along with the corresponding HLA-Bw4*80I ligand was associated with significantly heightened target cell-induced NK degranulation and cytokine secretion following IFNα stimulation (P = 0.0201, n = 13). Interestingly, we observed a significant inverse association between the IFNα stimulated NK response to K562 cells and the HIV-specific CD8 T-cell response to Gag among elite controllers (rho = -0.8321, P = 0.0010, n = 12).

CONCLUSION

Together, these results suggest that heightened NK responses can be evidenced independently of HIV-specific T-cell responses in HIV-1-infected elite controllers.

Antiviral inhibitory capacity of CD8+ T cells predicts the rate of CD4+ T-cell decline in HIV-1 infection

BACKGROUND

Rare human immunodeficiency virus type 1 (HIV-1)-infected individuals who maintain control of viremia without therapy show potent CD8+ T-cell-mediated suppression of viral replication in vitro. Whether this is a determinant of the rate of disease progression in viremic individuals is unknown.

METHODS

We measured CD8+ T-cell-mediated inhibition of a heterologous HIV-1 isolate in 50 HIV-1-seropositive adults with diverse progression rates. Linear mixed models were used to determine whether CD8+ T-cell function could explain variation in the rate of CD4+ T-cell decline.

RESULTS

There was a significant interaction between CD8+ T-cell antiviral activity in vitro and the rate of CD4+ T-cell decline in chronically infected individuals (P < .0001). In a second prospective analysis of recently infected subjects followed for up to 3 years, CD8+ T-cell antiviral activity strongly predicted subsequent CD4+ T-cell decline (P < .0001) and explained up to 73% of the interindividual variation in the CD4+ T-cell slope. In addition, it was inversely associated with viral load set point (r = -0.68 and P = .002).

CONCLUSIONS

The antiviral inhibitory capacity of CD8+ T cells is highly predictive of CD4+ T-cell loss in early HIV-1 infection. It has potential as a benchmark of effective immunity in vaccine evaluation.

Impact of HIV type 1 DNA levels on spontaneous disease progression: a meta-analysis

Several studies have reported the prognostic strength of HIV-1 DNA with variable results however. The aims of the current study were to estimate more accurately the ability of HIV-1 DNA to predict progression of HIV-1 disease toward acquired immunodeficiency syndrome (AIDS) or death, and to compare the prognostic information obtained by HIV-1 DNA with that derived from plasma HIV-1 RNA. Eligible articles were identified through a comprehensive search of Medline, ISI Web of Science, Scopus, and Google Scholar. The analysis included univariate and bivariate random-effects models. The univariate meta-analysis of six studies involving 1074 participants showed that HIV-1 DNA was a strong predictive marker of AIDS [relative risk (RR): 3.01, 95% confidence interval (CI): 1.88-4.82] and of all-cause mortality (RR: 3.49, 95% CI: 2.06-5.89). The bivariate model using the crude estimates of primary studies indicated that HIV-1 DNA was a significantly better predictor than HIV-1 RNA of either AIDS alone (ratio of RRs=1.47, 95% CI: 1.05-2.07) or of combined (AIDS or death) progression outcomes (ratio of RRs=1.51, 95% CI: 1.11-2.05). HIV-1 DNA is a strong predictor of HIV-1 disease progression. Moreover, there is some evidence that HIV-1 DNA might have better predictive value than plasma HIV-1 RNA.

Gene array studies in HIV-1 infection

HIV-1-infected individuals exhibit remarkable variation in the onset of disease. Virus replication and disease progression depend on host cellular transcription and gene regulation in virus-specific target cells. Both viral and host factors are implicated in this differential regulation. Gene arrays and transcriptome analyses might shed light on why some infected individuals remain asymptomatic while others progress rapidly to AIDS. Here we review developments in HIV research using gene array technologies and the unifying concepts that have emerged from these studies. Gene set enrichment analysis has revealed gene signatures linked to disease progression involving pathways related to metabolism, apoptosis, cell-cycle dysregulation, and T-cell signaling. Macrophages contain anti-apoptotic signatures. Also, HIV-1 regulates previously under-emphasized cholesterol biosynthesis and energy production pathways. Notably, cellular pathways linked to a subset of HIV-infected individuals known as non-progressors contribute to survival and anti-viral responses.

Interleukin-2 production by polyfunctional HIV-1-specific CD8 T cells is associated with enhanced viral suppression

BACKGROUND

Assays to measure the induction of HIV-1-specific CD8 T-cell responses often rely on measurements of indirect effector function such as chemokine and cytokine production, which may not reflect direct elimination of an invading pathogen. Assessment of the functional ability of CD8 T cells to suppress HIV-1 replication has been viewed as a surrogate marker of an effectual immune response. To further investigate this, we measured the capacity of virus-specific CD8 T cells to inhibit HIV-1 replication in an in vitro suppression assay.

METHODS

We expanded 15 epitope-specific CD8 T-cell lines from peripheral blood mononuclear cells of chronically HIV--infected progressors (n = 5) and controllers (n = 4) who were not on antiretroviral therapy. Cell lines were tested for their ability to produce effector molecules (CD107a, IL-2, IFN-γ, TNF-α, perforin) and suppress virus replication in autologous CD4 T cells.

RESULTS

CD8 T-cell lines from both progressors and controllers had largely similar effector function profiles as determined by intracellular cytokine staining. In contrast, we observed that CD8 T-cell lines derived from controllers show enhanced virus suppression when compared with progressors. Virus suppression was mediated in an major histocompatibility complex-dependent manner and found to correlate with a polyfunctional IL-2 CD8 T-cell response.

CONCLUSIONS

Using a sensitive in vitro suppression assay, we demonstrate that CD8 T-cell-mediated suppression of HIV-1 replication is a marker of HIV-1 control. Suppressive capacity was found to correlate with polyfunctional IL-2 production. Assessment of CD8 T-cell-mediated suppression may be an important tool to evaluate vaccine-induced responses.

Acute retroviral syndrome and high baseline viral load are predictors of rapid HIV progression among untreated Argentinean seroconverters

Background

Diagnosis of primary HIV infection (PHI) has important clinical and public health implications. HAART initiation at this stage remains controversial.

Methods

Our objective was to identify predictors of disease progression among Argentinean seroconverters during the first year of infection, within a multicentre registry of PHI-patients diagnosed between 1997 and 2008. Cox regression was used to analyze predictors of progression (LT-CD4 < 350 cells/mm³, B, C events or death) at 12 months among untreated patients.

Results

Among 134 subjects, 74% presented with acute retroviral syndrome (ARS). Seven opportunistic infections (one death), nine B events, and 10 non-AIDS defining serious events were observed. Among the 92 untreated patients, 24 (26%) progressed at 12 months versus three (7%) in the treated group (p = 0.01). The 12-month progression rate among untreated patients with ARS was 34% (95% CI 22.5-46.3) versus 13% (95% CI 1.1-24.7) in asymptomatic patients (p = 0.04). In univariate analysis, ARS, baseline LT-CD4 < 350 cells/mm³, and baseline and six-month viral load (VL) > 100,000 copies/mL were associated with progression. In multivariate analysis, only ARS and baseline VL > 100,000 copies/mL remained independently associated; HR: 8.44 (95% CI 0.97-73.42) and 9.44 (95% CI 1.38-64.68), respectively.

Conclusions

In Argentina, PHI is associated with significant morbidity. HAART should be considered in PHI patients with ARS and high baseline VL to prevent disease progression.

CD4 dynamics over a 15 year-period among HIV controllers enrolled in the ANRS French observatory

Background

There are few large published studies of HIV controllers with long-term undetectable viral load (VL). We describe the characteristics and outcomes of 81 French HIV controllers.

Methods and Results

HIV controllers were defined as asymptomatic, antiretroviral-naïve persons infected ≥10 years previously, with HIV-RNA <400 copies/mL in >90% of plasma samples. All available CD4 and VL values were collected at enrolment. Mixed-effect linear models were used to analyze CD4 cell count slopes since diagnosis. HIV controllers represented 0.31% of all patients managed in French hospitals. Patients infected through intravenous drug use were overrepresented (31%) and homosexual men were underrepresented (26% of men) relative to the ANRS SEROCO cohort of subjects diagnosed during the same period. HIV controllers whose VL values were always below the detection limit of the assays were compared with those who had rare “blips” (<50% of VL values above the detection limit) or frequent blips (>50% of VL values above the detection limit). Estimated CD4 cell counts at HIV diagnosis were similar in the three groups. CD4 cell counts remained stable after HIV diagnosis in the “no blip” group, while they fell significantly in the two other groups (−0.26√CD4 and −0.28√CD4/mm³/year in the rare and frequent blip groups, respectively). No clinical, immunological or virological progression was observed in the no blip group, while 3 immunological and/or virological events and 4 cancers were observed in the blip subgroups.

Conclusions

Viral blips in HIV controllers are associated with a significant decline in CD4 T cells and may be associated with an increased risk of pathological events, possibly owing to chronic inflammation/immune activation.

Elite suppressors harbor low levels of integrated HIV DNA and high levels of 2-LTR circular HIV DNA compared to HIV+ patients on and off HAART

Elite suppressors (ES) are a rare population of HIV-infected individuals that are capable of naturally controlling the infection without the use of highly active anti-retroviral therapy (HAART). Patients on HAART often achieve viral control to similar (undetectable) levels. Accurate and sensitive methods to measure viral burden are needed to elucidate important differences between these two patient populations in order to better understand their mechanisms of control. Viral burden quantification in ES patients has been limited to measurements of total DNA in PBMC, and estimates of Infectious Units per Million cells (IUPM). There appears to be no significant difference in the level of total HIV DNA between cells from ES patients and patients on HAART. However, recovering infectious virus from ES patient samples is much more difficult, suggesting their reservoir size should be much smaller than that in patients on HAART. Here we find that there is a significant difference in the level of integrated HIV DNA in ES patients compared to patients on HAART, providing an explanation for the previous results. When comparing the level of total to integrated HIV DNA in these samples we find ES patients have large excesses of unintegrated HIV DNA. To determine the composition of unintegrated HIV DNA in these samples, we measured circular 2-LTR HIV DNA forms and found ES patients frequently have high levels of 2-LTR circles in PBMC. We further show that these high levels of 2-LTR circles are not the result of inefficient integration in ES cells, since HIV integrates with similar efficiency in ES and normal donor cells. Our findings suggest that measuring integration provides a better surrogate of viral burden than total HIV DNA in ES patients. Moreover, they add significantly to our understanding of the mechanisms that allow viral control and reservoir maintenance in this unique patient population.

A low T regulatory cell response may contribute to both viral control and generalized immune activation in HIV controllers

HIV-infected individuals maintaining undetectable viremia in the absence of therapy (HIV controllers) often maintain high HIV-specific T cell responses, which has spurred the development of vaccines eliciting HIV-specific T cell responses. However, controllers also often have abnormally high T cell activation levels, potentially contributing to T cell dysfunction, CD4+ T cell depletion, and non-AIDS morbidity. We hypothesized that a weak T regulatory cell (Treg) response might contribute to the control of viral replication in HIV controllers, but might also contribute to generalized immune activation, contributing to CD4+ T cell loss. To address these hypotheses, we measured frequencies of activated (CD38+ HLA-DR+), regulatory (CD4+CD25+CD127^dim), HIV-specific, and CMV-specific T cells among HIV controllers and 3 control populations: HIV-infected individuals with treatment-mediated viral suppression (ART-suppressed), untreated HIV-infected “non-controllers” with high levels of viremia, and HIV-uninfected individuals. Despite abnormally high T cell activation levels, controllers had lower Treg frequencies than HIV-uninfected controls (P = 0.014). Supporting the propensity for an unusually low Treg response to viral infection in HIV controllers, we observed unusually high CMV-specific CD4+ T cell frequencies and a strong correlation between HIV-specific CD4+ T cell responses and generalized CD8+ T cell activation levels in HIV controllers (P≤0.001). These data support a model in which low frequencies of Tregs in HIV controllers may contribute to an effective adaptive immune response, but may also contribute to generalized immune activation, potentially contributing to CD4 depletion.

No difference in Gag and Env immune-response profiles between vaccinated and non-vaccinated rhesus macaques that control immunodeficiency virus replication

Recent advances in human immunodeficiency virus (HIV) vaccine design have resulted in induction of strong CD4 T-cell proliferative and polyfunctional cytokine responses, which are also characteristic for long-term non-progressing (LTNP) HIV-infected individuals. However, limited information is available on the persistence of these responses after infection. Results from studies in non-human primates indicate that vaccine-induced immune responses are partially maintained upon viral infection and differ from the responses seen in non-vaccinated animals that typically progress to disease. However, it is unclear how these partially preserved responses compare to immune responses that are acquired naturally by LTNP animals. In this study, immune-response profiles were compared between vaccinated animals that, upon SHIV₈₉.₆ challenge, became infected but were able to control virus replication, and a group of animals having spontaneous control of this viral infection. Both groups were found to develop very similar immune responses with regard to induction of CD4 and CD8 T-cell polyfunctional cytokine responses, proliferative capacity and cytotoxic capacity, as measured by a standard ₅₁Cr release assay and more direct ex vivo and in vivo CTL assays. Hence, vaccinated animals that become infected, but control infection, appear to establish immune responses that are similar to those elicited by long-term non-progressors.

Immunity and immunopathology to viruses: what decides the outcome?

Many viruses infect humans and most are controlled satisfactorily by the immune system with limited damage to host tissues. Some viruses, however, do cause overt damage to the host, either in isolated cases or as a reaction that commonly occurs after infection. The outcome is influenced by properties of the infecting virus, the circumstances of infection and several factors controlled by the host. In this Review, we focus on host factors that influence the outcome of viral infection, including genetic susceptibility, the age of the host when infected, the dose and route of infection, the induction of anti-inflammatory cells and proteins, as well as the presence of concurrent infections and past exposure to cross-reactive agents.

Despite being highly diverse, immunovirological status strongly correlates with clinical symptoms during primary HIV-1 infection: a cross-sectional study based on 674 patients enrolled in the ANRS CO 06 PRIMO cohort

OBJECTIVES

To analyse immunovirological status during primary HIV-1 infection (PHI) according to contemporary clinical status and time since infection.

METHODS

Plasma HIV-RNA and peripheral blood mononuclear cell (PBMC) HIV-DNA levels and CD4 cell counts were determined at enrolment in the ANRS PRIMO cohort. Time since infection was estimated based on both the number of antibodies on western blot at enrolment (0-1, 2-4 or > or =5 specific antibodies) and the estimated interval between infection and enrolment based on clinical and epidemiological features. Patients were classified according to the presence or absence of clinical symptoms at enrolment.

RESULTS

Between 1996 and 2006, 674 patients were enrolled an estimated median of 47 days after infection. Median marker values were as follows: HIV-RNA 5.10 log(10) copies/mL (range <1.70-8.33); HIV-DNA 3.30 log(10) copies/10(6) PBMCs (<1.84-4.93); and 506 CD4 cells/mm(3) (40-1542). Median HIV-RNA and PBMC HIV-DNA levels were significantly higher in patients with 0 or 1 specific antibody (n = 71) than in patients with 2-4 (n = 228) or > or =5 antibodies (n = 375). Symptomatic patients had significantly higher HIV-RNA and PBMC HIV-DNA levels and lower CD4 cell counts. However, 10% of symptomatic patients recruited shortly after infection had favourable immunovirological status.

CONCLUSIONS

Plasma HIV-RNA, PBMC HIV-DNA and CD4 cell count values were highly diverse and correlated strongly with clinical status during PHI. Early diagnosis was not always associated with severe PHI. Combining PBMC HIV-DNA with HIV-RNA, CD4 cell count and clinical symptoms would have allowed identification of 179 patients (26.5%) at high risk of rapid disease progression who did not meet current guidelines for early treatment initiation.

Comparison of early CD4 T-cell count in HIV-1 seroconverters in Côte d'Ivoire and France: the ANRS PRIMO-CI and SEROCO cohorts

OBJECTIVE

We compared CD4+ decline among untreated HIV-1-infected seroconverters living in Côte d'Ivoire (CI) and in France.

METHODS

HIV-1-infected adults were enrolled in the ANRS1220 PRIMO-CI (CI, 1997-2006) and ANRSCO2 SEROCO (France, 1988-1995) cohorts. CD4+ count and percentage declines were estimated from enrollment until 24 months of seroconversion by linear random-effect models adjusted for time since seroconversion, age, gender, cell-associated HIV DNA, HIV RNA, and country.

RESULTS

Overall 521 seroconverters (CI 148, 62% men; France 373, 77% men) were enrolled after a median of 7.6 months since seroconversion. Median follow-up duration was 12.7 months. Median age was 28 years. Median baseline CD4+ count was 472 and 560 cells per cubic millimeter, respectively. Median baseline HIV RNA was 4.4 and 4.0 log10 copies per milliliter and median HIV DNA was 3.0 and 2.8 log10 copies per 10(6) peripheral blood mononuclear cells, respectively. In adjusted models, CD4+ count and percentage at baseline were lower in CI than in France (P < 0.01), and the difference did not vary during follow-up (P = 0.55). Low HIV RNA and low HIV DNA at baseline were associated with higher CD4+ count at baseline.

CONCLUSIONS

CD4+ count and percentage were lower in CI than in France. These differences were already observed during early infection and remained similar after adjustment.

Antiretroviral therapy in acute and recent HIV infection: a prospective multicenter stratified trial of intentionally interrupted treatment

BACKGROUND

Antiretroviral therapy in early HIV infection may enhance outcome and viral control may be better in acute versus recent infection 24 weeks after treatment interruption.

METHODS

A prospective trial of treatment stratified by acute versus recent HIV-1 infection. If HIV viral load <50 copies/ml after at least 52 weeks, treatment was interrupted. If viremia rebounded, treatment and interruption were repeated. The primary endpoint was maintaining viral load less than 5000 copies/ml for 24 weeks following treatment interruption.

RESULTS

Of the 121 patients enrolled at 15 sites, ninety-five percent were men, median age was 34 years; 69% were white. Median viral load was higher in acute HIV-1 infection (210 000 copies/ml) than recent HIV-1 infection (43 000 copies/ml). The 73 primary endpoint patients (28 acute HIV-1 infection, 45 recent HIV-1 infection) had significantly higher baseline CD4 T-cell counts (P = 0.044) and lower viral load (P = 0.016). The primary endpoint was achieved in 29 (40%) of the 73 and in 24% of the 121 enrolled overall. There was no significant outcome difference (P = 0.81) between the acute HIV-1 infection [43%, 95% confidence interval (CI) 24-63%] and recent HIV-1 infection (38%, 95% CI 24-53%) groups. Differences after longer follow-up can not be ascertained by this trial. Baseline viral load less than 100 000/ml 22/46 (48%) compared with more than 100 000/ml, 7/27 (26%) and higher baseline CD4 immune activation predicted success.

CONCLUSION

Forty percent of patients treated during acute HIV-1 infection or recent HIV-1 infection sustained a viral load less than 5000 copies/ml after 24 weeks of treatment interruption.

No evidence of a change in HIV-1 virulence since 1996 in France

OBJECTIVE

We investigated temporal trends in the CD4 cell count and in plasma HIV RNA and total HIV DNA levels measured at the time of primary HIV infection, as proxies for HIV-1 virulence, taking changes in patient characteristics into account.

DESIGN

We studied 903 patients enrolled during primary HIV infection in the French multicenter ANRS PRIMO cohort from 1996 to 2007.

METHODS

Associations between the year of primary HIV infection and the values of the three markers were tested with regression models. The year of primary HIV infection was first introduced as a restricted cubic splines function in a regression model in order to explore the shape of the associations, and then as a continuous/categorical variable. The following confounders were considered in multiple regression analysis: time since infection and age (introduced as restricted cubic spline functions), sex, place of birth (Africa vs. others), symptomatic primary HIV infection, smoking, and virus-related factors (subtype B vs. non-B, and drug resistance mutations).

RESULTS

Multivariate analysis showed no temporal trends in the CD4 cell count (square-root) or in HIV-1 RNA and DNA levels (log10) measured at the time of primary HIV infection. We observed the well described associations between the prognostic markers and the time since infection, sex, symptomatic primary HIV infection, and smoking.

CONCLUSION

The CD4 cell count and HIV RNA and DNA levels measured at the time of primary HIV-1 infection remained stable across 12 consecutive years (1996-2007) in the ANRS PRIMO cohort, suggesting no major change in virulence, after taking into account changes in patient characteristics.

Clinical prognostic value of RNA viral load and CD4 cell counts during untreated HIV-1 infection--a quantitative review

Background

The prognostic value of CD4 counts and RNA viral load for identifying treatment need in HIV-infected individuals depends on (a) variation within and among individuals, and (b) relative risks of clinical progression per unit CD4 or RNA difference.

Methodology/Principal Findings

We reviewed these measurements across (a) 30 studies, and (b) 16 cohorts of untreated seropositive adults. Median within-population interquartile ranges were 74,000 copies/mL for RNA with no significant change during the course of infection; and 330 cells/µL for CD4, with a slight proportional increase over infection. Applying measurement and physiological fluctuations observed on chronically infected patients, we estimate that 45% of population-level variation in RNA, and 25% of variation in CD4, were due to within-patient fluctuations. Comparing a patient with RNA at upper 75^th centile with a patient at median RNA, 5-year relative risks were 1.4 (95% CI 1.2–1.7) for AIDS and 1.5 (1.3–1.9) for death, without change over the course of infection. In contrast, for a patient with CD4 count at the lower 75^th centile, relative risks increased from 1.0 at seroconversion to maxima of 6.3 (4.4–8.9) for AIDS and 5.5 (2.7–10.1) for death by year 6, when the population median had fallen to 300 cells/µL. Below 300 cells/µL, prognostic power did not increase, due to a narrower CD4 range.

Conclusions

Findings support the current WHO recommendation (used with clinical criteria) to start antiretroviral treatment in low-income settings at CD4 thresholds of 200–350 cells/µL, without pre-treatment RNA monitoring – while not precluding earlier treatment based on clinical, socio-demographic or public health criteria.