T-cell activation positively correlates with cell-associated HIV-DNA level in viremic patients with primary or chronic HIV-1 infection

External quality assessment of HIV-1 DNA quantification assays used in the clinical setting in Italy

Total cell-associated HIV-1 DNA is a surrogate marker of the HIV-1 reservoir, however, certified systems for its quantification are not available. The Italian HIV DNA Network was launched to validate HIV-1 DNA quantification methods in use at University and Hospital labs. A quality control panel including HIV-1 DNA standards, reconstructed blood samples (RBSs) and DNA from different HIV-1 subtypes was blindly tested by 12 participating labs by quantitative real-time PCR (n = 6), droplet digital PCR (n = 3) or both (n = 3). The median 95% hit rate was 4.6 (3.7–5.5) copies per test and linearity in the tested range was excellent (R2 = 1.000 [1.000–1.000]). The median values obtained across labs were 3,370 (2,287–4,245), 445 (299–498), 59 (40–81) and 7 (6–11) HIV-1 DNA copies, for the 3,584, 448, 56 and 7-copy standards, respectively. With RBSs, measured values were within twofold with respect to the median in two thirds of cases. HIV-1 subtypes were missed (CRF01_AE by 3 labs) or underestimated by > 1 log (subtypes A, C, D, F by one lab; CRF01_AE by one lab; CRF02_AG by one lab). The overall performance was excellent with HIV-1 DNA standards, however detection of different HIV-1 subtypes must be improved.

Quantification of Total HIV DNA as a Marker to Measure Viral Reservoir: Methods and Potential Implications for Clinical Practice

The focus of this review is to examine the importance of quantifying total HIV DNA to target the HIV reservoir and the clinical implications and challenges involved in its future application in clinical practice. Despite intrinsic limitations, the quantification of total HIV DNA is currently the most widely used marker for exploring the HIV reservoir. As it allows estimating all forms of HIV DNA in the infected cells, total HIV DNA load is the biomarker of the HIV reservoir that provides most of the insights into HIV pathogenesis. The clinical role of total HIV-DNA in both untreated and treated patients is extensively supported by important lines of evidence. Thus, predictive models that include total HIV DNA load together with other variables could constitute a prognostic tool for use in clinical practice. To date, however, this marker has been primarily used in experimental evaluations. The main challenge is technical. Although the implementation of droplet digital PCR could improve analytical performance over real-time PCR, the lack of standardization has made cross-comparisons of the data difficult. An effort by investigators to compare protocols is needed. Furthermore, the main effort now should be to involve the biomedical industry in the development of certified assays for in vitro diagnostics use.

Increased Platelet-CD4+ T Cell Aggregates Are Correlated With HIV-1 Permissiveness and CD4+ T Cell Loss

Chronic HIV-1 infection is associated with persistent inflammation, which contributes to disease progression. Platelet-T cell aggregates play a critical role in maintaining inflammation. However, the phenotypic characteristics and clinical significance of platelet-CD4+ T cell aggregates remain unclear in different HIV-infected populations. In this study, we quantified and characterized platelet-CD4+ T cell aggregates in the peripheral blood of treatment-naïve HIV-1-infected individuals (TNs), immunological responders to antiretroviral therapy (IRs), immunological non-responders to antiretroviral therapy (INRs), and healthy controls (HCs). Flow cytometry analysis and immunofluorescence microscopy showed increased platelet-CD4+ T cell aggregate formation in TNs compared to HCs during HIV-1 infection. However, the frequencies of platelet-CD4+ T cell aggregates decreased in IRs compared to TNs, but not in INRs, which have shown severe immunological dysfunction. Platelet-CD4+ T cell aggregate frequencies were positively correlated with HIV-1 viral load but negatively correlated with CD4+ T cell counts and CD4/CD8 ratios. Furthermore, we observed a higher expression of CD45RO, HIV co-receptors, HIV activation/exhaustion markers in platelet-CD4+ T cell aggregates, which was associated with HIV-1 permissiveness. High levels of caspase-1 and caspase-3, and low levels of Bcl-2 in platelet-CD4+ T cell aggregates imply the potential role in CD4+ T cell loss during HIV-1 infection. Furthermore, platelet-CD4+ T cell aggregates contained more HIV-1 gag viral protein and HIV-1 DNA than their platelet-free CD4+ T cell counterparts. The platelet-CD4+ T cell aggregate levels were positively correlated with plasma sCD163 and sCD14 levels. Our findings demonstrate that platelet-CD4+ T cell aggregate formation has typical characteristics of HIV-1 permissiveness and is related to immune activation during HIV-1 infection.

SAMHD1 expression is associated with low immune activation but not correlated with HIV‑1 DNA levels in CD4+ T cells of patients with HIV‑1

Sterile α motif and histidine/aspartic acid domain‑containing protein 1 (SAMHD1) can inhibit reverse transcription of human immunodeficiency virus‑1 (HIV‑1) by hydrolyzing intracellular deoxy‑ribonucleoside triphosphate. However, its role in HIV‑1 disease progression has not been extensively studied. To study the impacts of SAMHD1 on HIV‑1 disease progression, especially on DNA levels, we investigated SAMHD1 levels in the peripheral blood of HIV‑1 elite controllers (ECs), antiretroviral therapy (ART) naive viremic progressors (VPs) and patients with HIV‑1 receiving ART (HIV‑ARTs) compared with healthy controls. In addition, the present study analyzed the relationship between SAMHD1 and interferon‑α, immune activation and HIV‑1 DNA levels. The results of the present study demonstrated elevated SAMHD1 expression in the peripheral blood mononuclear cells of all patients withHIV‑1, but higher SAMHD1 expression in the CD4+ T cells of only ECs compared with healthy controls. Immune activation was increased in the VPs and decreased in the ECs compared with healthy controls. Substantially lower HIV‑1 DNA levels were identified in ECs compared with those in VPs and HIV‑ARTs. SAMHD1 expression was associated with low levels of immune activation. No significant correlation was observed between SAMHD1 and HIV‑1 DNA levels. Overall, the findings of the present study indicated that SAMHD1 was highly expressed in ECs, which may be associated with low immune activation levels, but was not directly related to HIV‑1 DNA levels.

Quantification of HIV-DNA and residual viremia in patients starting ART by droplet digital PCR: Their dynamic decay and correlations with immunological parameters and virological success

BACKGROUND

Accurate quantification of total HIV-DNA and residual-viremia by sensitive assays is extremely useful to optimize monitoring of ART-treated patients.

OBJECTIVES

To evaluate the performances of two ddPCR-based assays for HIV-DNA and residual-viremia quantification, and the correlations of pre-ART HIV-DNA with plasma HIV-RNA, CD4 + T, CD4/CD8 and virological-success (VS) during first-line ART.

STUDY DESIGN

Plasma HIV-RNA, total HIV-DNA, CD4 + T, CD4/CD8 were evaluated at baseline of ART, at VS (viral-load <50copies/ml), and at 6 months after VS (6moVS) in 57 newly-diagnosed HIV-1 infected patients, receiving first-line modern ART. HIV-DNA (log10 copies/106CD4 + T) and residual-viremia (copies/ml) were measured with in-house ddPCR assays. Correlations were assessed by Spearman and Jonckheere-Terpstra tests.

RESULTS

HIV-DNA and residual-viremia assays showed a good linear trend between the expected and obtained values (R2 = 0.9913 and 0.9945); lower limits of detection were 32 copies/106CD4 + T and 2 copies/ml, respectively. At baseline, median (IQR) plasma HIV-RNA and HIV-DNA were 4.88(4.28-5.36)log10 copies/ml and 4.00(3.36-4.51) log10 copies/106CD4 + T cells. Residual-viremia was 8(2-26) and 4(2-12) copies/ml at VS and 6moVS. Pre-ART HIV-DNA positively correlated with plasma HIV-RNA at BL (Rho = 0.708, p < 0.001), and with residual-viremia at VS (Rho:0.383,p = 0.002). Notably, higher HIV-DNA correlated with longer time to achieve VS (median[IQR],weeks: 17.8[12.3-29.0] for HIV-DNA ≥4.5 vs. 7.4[4.1-8.7] for HIV-DNA<4.5, p < 0.001). Furthermore, pre-ART HIV-DNA negatively correlated with CD4 + T and CD4/CD8 at baseline, VS and 6moVS.

CONCLUSIONS

Our results support the adoption of ddPCR-based assays for both HIV-DNA and residual-viremia quantifications and corroborate that pre-ART HIV-DNA is an excellent indicator in predicting viroimmunological response and VS in patients starting ART.

Single-cell characterization and quantification of translation-competent viral reservoirs in treated and untreated HIV infection

The phenotypic characterization of the cells in which HIV persists during antiretroviral therapy (ART) remains technically challenging. We developed a simple flow cytometry-based assay to quantify and characterize infected cells producing HIV proteins during untreated and treated HIV infection. By combining two antibodies targeting the HIV capsid in a standard intracellular staining protocol, we demonstrate that p24-producing cells can be detected with high specificity and sensitivity in the blood from people living with HIV. In untreated individuals, the frequency of productively infected cells strongly correlated with plasma viral load. Infected cells preferentially displayed a transitional memory phenotype and were enriched in Th17, peripheral Tfh and regulatory T cells subsets. These cells also preferentially expressed activation markers (CD25, HLA-DR, Ki67), immune checkpoint molecules (PD-1, LAG-3, TIGIT, Tim-3) as well as the integrins α4β7 and α4β1. In virally suppressed individuals on ART, p24-producing cells were only detected upon stimulation (median frequency of 4.3 p24+ cells/10⁶ cells). These measures correlated with other assays assessing the size of the persistent reservoir including total and integrated HIV DNA, Tat/rev Induced Limiting Dilution Assay (TILDA) and quantitative viral outgrowth assay (QVOA). In ART-suppressed individuals, p24-producing cells preferentially displayed a transitional and effector memory phenotype, and expressed immune checkpoint molecules (PD-1, TIGIT) as well as the integrin α4β1. Remarkably, α4β1 was expressed by more than 70% of infected cells both in untreated and ART-suppressed individuals. Altogether, these results highlight a broad diversity in the phenotypes of HIV-infected cells in treated and untreated infection and suggest that strategies targeting multiple and phenotypically distinct cellular reservoirs will be needed to exert a significant impact on the size of the reservoir.

HIV persists in a small pool of infected CD4+ T cells during ART. A better characterization of these cells is a pre-requisite to the development of HIV eradication strategies. We developed a novel assay, named HIV-Flow, to simultaneously quantify and characterize reservoir cells in individuals receiving ART. With this assay, we found that a median of only 5 cells/million have the ability to produce the HIV protein Gag in individuals on suppressive ART. These frequencies correlated with other assays aimed at measuring HIV reservoirs. Importantly, we show that the HIV reservoir is phenotypically diverse, with numerous cell subsets contributing to the pool of persistently infected cells. Nonetheless, we identified several markers preferentially expressed at the surface or these rare reservoir cells, including immune checkpoint molecules and homing receptors. By combining these markers, we identified discrete cellular subsets highly enriched in HIV-infected cells. This novel assay will facilitate the identification of markers expressed by cellular HIV reservoirs.

[Causes of T lymphocyte activation in HIV-infected patients coinfected with hepatitis C virus]

AIM

To establish the causes of T lymphocyte activation in human immunodeficiency virus (HIV)-infected patients coinfected with hepatitis C (HCV) who are adherent to their antiretroviral therapy regimen and interferon untreated.

SUBJECTS AND METHODS

Examinations were made in 62 people who were HIV+HCV-positive (n=21), HIV+HCV-negative (n=21), and noninfected volunteers (n=20). The activation (CD38+HLA-DR+) and proliferation (Ki-67+) of CD4+ and CD8+ T lymphocytes were estimated. The blood concentration of intestinal fatty acid-binding protein (I-FABP) was determined.

RESULTS

The proportion of activated cells among the CD4+ T lymphocytes was equal in the HIV+HCV-positive and HIV+HCV-negative groups. But these indicators were statistically significantly higher than those in the controls (HIV- HCV-). CD8+ T cell activation was greater in the HIV/HCV-coinfected patients than that in the other groups and that was higher in the HIV monoinfected than in the noninfected. The blood I-FABP concentrations were elevated in the HIV+HCV-positive and HIV+HCV groups compared with those in the HIV-HCV-negative group, but these did not differ among themselves. In the HIV+HCV-negative patients, CD4+ and CD8+ T cell activation directly and statistically significantly correlated with blood I-FABP levels. In the HIV+HCV-positive group, this correlation remained only for CD4+ T lymphocytes. CD8+ T cell activation in HIV/HCV-coinfected patients was unrelated to I-FABP concentrations.

CONCLUSION

The increased activation of CD4+ and CD8+ T lymphocytes in HIV monoinfection was found to be associated with intestinal epithelial destruction and unrelated to cell division processes. In HIV/HCV coinfection, the activated state of CD4+ T cells is determined by both the level of proliferative processes and impairment of the intestinal barrier and that of CD8+ T cells is only by proliferation.

Single-cell analysis identifies cellular markers of the HIV permissive cell

Cellular permissiveness to HIV infection is highly heterogeneous across individuals. Heterogeneity is also found across CD4+ T cells from the same individual, where only a fraction of cells gets infected. To explore the basis of permissiveness, we performed single-cell RNA-seq analysis of non-infected CD4+ T cells from high and low permissive individuals. Transcriptional heterogeneity translated in a continuum of cell states, driven by T-cell receptor-mediated cell activation and was strongly linked to permissiveness. Proteins expressed at the cell surface and displaying the highest correlation with T cell activation were tested as biomarkers of cellular permissiveness to HIV. FACS sorting using antibodies against several biomarkers of permissiveness led to an increase of HIV cellular infection rates. Top candidate biomarkers included CD25, a canonical activation marker. The combination of CD25 high expression with other candidate biomarkers led to the identification of CD298, CD63 and CD317 as the best biomarkers for permissiveness. CD25highCD298highCD63highCD317high cell population showed an enrichment of HIV-infection of up to 28 fold as compared to the unsorted cell population. The purified hyper-permissive cell subpopulation was characterized by a downregulation of interferon-induced genes and several known restriction factors. Single-cell RNA-seq analysis coupled with functional characterization of cell biomarkers provides signatures of the "HIV-permissive cell".

Evaluation of HIV-DNA and inflammatory markers in HIV-infected individuals with different viral load patterns

BACKGROUND

Persistent residual viremia (RV) and low grade inflammation and immune activation have been associated with non-AIDS defining events. The impact of persistent RV and HIV-DNA load on immune activation/inflammation remains unclear. The purpose of this study was to gain new insights into the relation between viremia, markers of inflammation and HIV-DNA levels.

METHODS

Three hundred and twenty-one HIV-infected patients were studied. A retrospective analysis of viremia values, prospectively collected for 48 months, was performed. Patients were separated into three groups: 113 TND (Target Not Detected, patients with sustained undetectable viremia); 113 RV (Residual Viremia, patients who had at least three detectable viral load (VL) values <37 copies/ml); 95 LLV (Low Level Viremia, patients with at least two VL values >37 but <200 copies/ml). HIV-DNA, TNF-α, IL-6 and sCD14 were analyzed.

RESULTS

HIV-DNA, sCD14 and TNF-α were significantly lower in the TND group than in the RV and LLV groups. In addition, RV patients showed lower levels of HIV-DNA and sCD14 than LLV individuals. HIV-DNA load was not related to markers of inflammation. The ordinal logistic analysis showed that two independent variables were significantly associated with VL pattern: sCD14, HIV-DNA. In addition NRTIs plus NNRTIs and NRTIs plus PIs were negatively associated to VL pattern compared to INI-containing regimen.

CONCLUSIONS

Persistent undetectable viremia was associated with lower levels of inflammatory markers and HIV-DNA. However, the lack of normalization of these biomarkers in the TND group and the fact that HIV-DNA load was not associated with inflammation strongly suggest that other mechanisms play a major role in maintaining inflammation over time.

Impact of early cART on HIV blood and semen compartments at the time of primary infection

BACKGROUND

HIV-infected cells in semen facilitate viral transmission. We studied the establishment of HIV reservoirs in semen and blood during PHI, along with systemic immune activation and the impact of early cART.

METHODS

Patients in the ANRS-147-OPTIPRIM trial received two years of early cART. Nineteen patients of the trial were analyzed, out of which 8 had acute PHI (WB ≤1 Ab). We quantified total cell-associated (ca) HIV-DNA in blood and semen and HIV-RNA in blood and semen plasma samples, collected during PHI and at 24 months of treatment.

RESULTS

At enrollment, HIV-RNA load was higher in blood than in semen (median 5.66 vs 4.22 log10 cp/mL, p<0.0001). Semen HIV-RNA load correlated strongly with blood HIV-RNA load (r = 0.81, p = 0.02, the CD4 cell count (r = -0.98, p<0.0001), and the CD4/CD8 ratio (r = -0.85, p<0.01) in acute infection but not in later stages of PHI. Median blood and seminal cellular HIV-DNA levels were 3.59 and 0.31 log10cp/106 cells, respectively. HIV-DNA load peaked in semen later than in blood and then correlated with blood IP10 level (r = 0.62, p = 0.04). HIV-RNA was undetectable in blood and semen after two years of effective cART. Semen HIV-DNA load declined similarly, except in one patient who had persistently high IP-10 and IL-6 levels and used recreational drugs.

CONCLUSIONS

HIV reservoir cells are found in semen during PHI, with gradual compartmentalization. Its size was linked to the plasma IP-10 level. Early treatment purges both the virus and infected cells, reducing the high risk of transmission during PHI.

CLINICAL TRIALS REGISTRATION

NCT01033760.

Human Immunodeficiency Virus Persistence and T-Cell Activation in Blood, Rectal, and Lymph Node Tissue in Human Immunodeficiency Virus-Infected Individuals Receiving Suppressive Antiretroviral Therapy

Background

Immune activation and inflammation remain elevated in human immunodeficiency virus (HIV)-infected individuals receiving antiretroviral therapy (ART) and may contribute to HIV persistence.

Methods

Using flow cytometry expression of CD38, HLA-DR and PD-1 were measured in blood (n = 48), lymph node (LN; n = 9), and rectal tissue (n = 17) from virally suppressed individuals. Total and integrated HIV DNA, 2-LTR circles, and cell-associated unspliced HIV RNA were quantified.

Results

CD4+ T cells from rectal tissue had a higher frequency of integrated HIV DNA compared with blood (4.26 fold-change in DNA; 95% confidence interval [CI] = 2.61-7.00; P < .001) and LN (2.32 fold-change in DNA; 95% CI = 1.22-4.41; P = .01). In rectal tissue, there were positive associations between integrated HIV DNA with PD-1+ CD4+ T-cells (1.44 fold-change in integrated HIV DNA per 10-unit increase in PD-1+ CD4+ T cells; 95% CI = 1.01-2.05; P = .045) and CD38+HLA-DR+ CD8+ T cells (1.40 fold-change in integrated HIV DNA per 1-unit increase in CD38+HLA-DR+ CD8+ T cells; 95% CI = 1.05-1.86; P = .02). Both associations were independent of current and nadir CD4+ T-cell counts.

Conclusions

During ART, rectal tissue is an important reservoir for HIV persistence with a high frequency of activated CD4+ and CD8+ T cells. PD-1 may represent a marker of HIV persistence in rectal tissue.

Total HIV-1 DNA, a Marker of Viral Reservoir Dynamics with Clinical Implications

HIV-1 DNA persists in infected cells despite combined antiretroviral therapy (cART), forming viral reservoirs. Recent trials of strategies targeting latent HIV reservoirs have rekindled hopes of curing HIV infection, and reliable markers are thus needed to evaluate viral reservoirs. Total HIV DNA quantification is simple, standardized, sensitive, and reproducible. Total HIV DNA load influences the course of the infection and is therefore clinically relevant. In particular, it is predictive of progression to AIDS and death, independently of HIV RNA load and the CD4 cell count. Baseline total HIV DNA load is predictive of the response to cART. It declines during cART but remains quantifiable, at a level that reflects both the history of infection (HIV RNA zenith, CD4 cell count nadir) and treatment efficacy (residual viremia, cumulative viremia, immune restoration, immune cell activation). Total HIV DNA load in blood is also predictive of the presence and severity of some HIV-1-associated end-organ disorders. It can be useful to guide individual treatment, notably, therapeutic de-escalation. Although it does not distinguish between replication-competent and -defective latent viruses, the total HIV DNA load in blood, tissues, and cells provides insights into HIV pathogenesis, probably because all viral forms participate in host cell activation and HIV pathogenesis. Total HIV DNA is thus a biomarker of HIV reservoirs, which can be defined as all infected cells and tissues containing all forms of HIV persistence that participate in pathogenesis. This participation may occur through the production of new virions, creating new cycles of infection and disseminating infected cells; maintenance or amplification of reservoirs by homeostatic cell proliferation; and viral transcription and synthesis of viral proteins without new virion production. These proteins can induce immune activation, thus participating in the vicious circle of HIV pathogenesis.

Immune activation during acute HIV infection and the impact of early antiretroviral therapy

PURPOSE OF REVIEW

The purpose of this review is to outline recent data pertaining to mechanisms of immune activation in acute infection and describe new developments that seek to determine if early antiretroviral treatment can mitigate chronic immune activation.

RECENT FINDINGS

Following the detection of HIV RNA, highly activated CD8 T cells expand and peak approximately 2 weeks following peak viral load whereas levels of proinflammatory soluble markers coincide with a rise in viral load. Immune activation during acute infection is driven by many factors including pyroptosis, replicative capacity of the infecting virus, and loss of Th17 cells within the gut. Early antiretroviral therapy (ART), particularly if initiated in Fiebig I (HIV IgM-), preserved mucosal CD4 T cells, possibly preventing the release of microbial products associated with immune activation. Viral reservoirs were restricted by the early initiation of ART, and heightened systemic immune activation was partially prevented compared with chronic HIV infection. A strong correlation was found between the size of the viral reservoir and cellular immune activation.

SUMMARY

The timing of immune activation during acute infection occurs shortly after exposure. Recent studies demonstrated that ART mitigates inflammatory responses, preserves CD4 T cells, and limits reservoir seeding if provided early in acute HIV infection.

CD4 T-Cell Responses in Primary HIV Infection: Interrelationship with Immune Activation and Virus Burden

Early events during primary HIV infection (PHI) are thought to influence disease outcome. Although a growing body of evidence suggests a beneficial role of HIV-specific CD4 help in HIV infection, it is unclear how early viral replication, systemic immune activation, and antiretroviral therapy (ART) may shape CD4 T-cell responses during PHI, and whether HIV-specific CD4 responses contribute to the high immune activation observed in PHI. Twenty-seven patients with early PHI were included in a prospective longitudinal study and 12 of them received ART after enrollment. Fresh peripheral blood mononuclear cells were used for measurement of ex vivo T-cell activation and of cytokine-producing CD4 T-cells following stimulation with PMA/ionomycin or HIV-1-gag-p24 antigen. Patients were segregated based on CD8 T-cell activation level (i.e., % HLA-DR⁺CD38⁺ CD8 T-cells) at baseline (BL). Patients with lower immune activation exhibited higher frequency of bulk CD4 T-cells producing IFN-γ or IL-17 and higher effector-to-regulatory cell ratios. No differences were found in HIV-specific CD4 T-cell frequencies. In contrast, segregation of patients based on plasma viral load (pVL) revealed that patients with higher pVL showed higher cytokine-producing HIV-specific CD4 responses. Of note, the frequency of IFN-γ⁺ HIV-specific CD4 T cells significantly diminished between BL and month 6 only in ART-treated patients. However, early treatment initiation was associated with better maintenance of HIV-specific IFN-γ⁺ CD4 T-cells. These data suggest that HIV-specific CD4 responses do not fuel systemic T-cell activation and are driven by viral replication but not able to contribute to its control in the early phase of infection. Moreover, our data also suggest a benefit of early treatment for the maintenance of HIV-specific CD4 T-cell help.

Immunity, inflammation and reservoir in patients at an early stage of HIV infection on intermittent ART (ANRS 141 TIPI Trial)

OBJECTIVES

The objective of this study was to assess clinical and biological changes during intermittent ART (I-ART) started early, with significant time spent on versus off ART, which has never before been studied in ART-naive patients with high nadir and current CD4 cell count.

PATIENTS AND METHODS

ART-naive HIV-1-infected patients with baseline CD4 ≥ 500/mm(3) and nadir CD4 ≥ 400/mm(3) received 2 years of I-ART (6 month periods on once-daily boosted-PI-based ART, alternating with 6 month periods without ART) in a 2 year, Phase II, non-comparative multicentre trial. The trial is registered with ClinicalTrials.gov, number NCT 00820118.

RESULTS

The CD4 cell count remained ≥ 500/mm(3) at 2 years in all 44 patients included in the study. The mean 2 year count was higher than the mean count at baseline in 24 patients overall (55%; 95% CI 40%-69%) and in 20 (65%; 95% CI 48%-81%) of the 31 patients who fully adhered to the trial strategy. All but three of these latter patients had HIV-1 RNA concentrations below 50 copies/mL after each 6 month 'on' period. Only one strategy-related genotypic mutation (M184I) was detected. The HIV-1 DNA median load fluctuated, but it did not differ between month 0 and month 24 (2.8 versus 2.6 log10 copies/10(6) leucocytes, P = 0.29). Biomarkers of inflammation and endothelial activation remained stable between month 0 and month 24. Naive CD4, CD8+CCR5+ and CD8+CD38+ T cell numbers tended to decline. One patient developed Burkitt's lymphoma and 12 patients reported sexually transmitted infections.

CONCLUSIONS

In patients with high nadir and current CD4 cell counts, 2 year I-ART maintained the CD4 cell count above 500/mm(3), with no increase in the viral reservoir. Immune activation seems related to HIV replication, while inflammation seems to evolve independently and require specific attention.

Association of microbial translocation biomarkers with clinical outcome in controllers HIV-infected patients

BACKGROUND

A proportion of patients who spontaneously control viral load (controllers) experienced clinical progression. We hypothesized that microbial translocation would independently determine the rate of disease progression in controllers.

METHODS

sCD14, lipopolysaccharide-binding protein (LBP) and EndoCab levels were assessed in 114 antiretroviral-naive patients with CD4(+) T cells above 500 cells/μl (including 63 controllers and 51 noncontrollers). The independent predictive value of these markers on time to progression to the combined endpoint of AIDS, non-AIDS event, initiation of combination antiretroviral therapy (cART) or CD4(+) cell count less than 500 cells/μl was assessed using a Cox regression model.

RESULTS

Most of the patients progressed to a combined endpoint (60%). Clinical progression in controllers was significantly lower than in noncontrollers (P = 0.02). Controllers with lower than the median baseline CD4(+) T-cell count and higher than the median baseline viral load, sCD14 and EndoCab levels had a worse prognosis (P < 0.0001, P = 0.007, P = 0.05 and P = 0.012), while noncontrollers with higher than the median baseline LBP level also had a worse prognosis (P = 0.019). sCD14 and LBP increased and EndoCab decreased over time [from baseline (median values: 1486, 17604 ng/ml and 68 MMU/ml, respectively, to the date of event or the last determination (median values: 1663, 20230 ng/ml and 49 MMU/ml), respectively] in controllers (P = 0.04, 0.08 and 0.0006, respectively).

CONCLUSION

Microbial translocation seems to be an important determinant of clinical progression in HIV-infected controllers independently of viremia. Measures to improve the intestinal mucosa damage or decrease translocation could influence the outcome in these patients.

Phenotype alterations in regulatory T-cell subsets in primary HIV infection and identification of Tr1-like cells as the main interleukin 10-producing CD4+ T cells

BACKGROUND

Conventional regulatory T cells (Tregs) can suppress human immunodeficiency virus type 1 (HIV-1)-specific immune responses but cannot control immune activation in primary HIV infection. Here, we characterized Treg subsets, using recently defined phenotypic delineation, and analyzed the relative contribution of cell subsets to the production of immunosuppressive cytokines in primary HIV infection.

METHODS

In a longitudinal prospective study, ex vivo phenotyping of fresh peripheral blood mononuclear cells from patients with primary HIV infection was performed at baseline and month 6 of follow-up to characterize Treg subsets, immune activation, and cytokine production in isolated CD4(+) T cells.

RESULTS

The frequency of CD4(+)CD25(+)CD127(low) Tregs and the distribution between the naive, memory, and activated/memory Treg subsets was similar in patients and healthy donors. However, Tregs from patients with primary HIV infection showed peculiar phenotypic profiles, such as elevated FoxP3, ICOS, and CTLA-4 expression, with CTLA-4 expression strikingly increased in all Treg subsets both at baseline and month 6 of follow-up. The great majority of interleukin 10 (IL-10)-producing CD4(+) T cells were FoxP3(neg) (ie, Tr1-like cells). In contrast to conventional Tregs, Tr1-like cells were inversely correlated with immune activation and not associated with lower effector T-cell responses.

CONCLUSION

FoxP3(neg) Tr1-like cells-major contributors to IL-10 production-may have a beneficial role by controlling immune activation in early HIV infection.