Rapid activation of lymph nodes and mononuclear cell HIV expression upon interrupting highly active antiretroviral therapy in patients after prolonged viral suppression

MRP8/14 Is a Molecular Signature Triggered by Dopamine in HIV Latent Myeloid Targets That Increases HIV Transcription and Distinguishes HIV+ Methamphetamine Users with Detectable CSF Viral Load and Brain Pathology

There is a significant overlap between HIV infection and substance-use disorders. Dopamine (DA) is the most abundantly upregulated neurotransmitter in methamphetamine abuse, with receptors (DRD1-5) that are expressed by neurons as well as by a large diversity of cell types, including innate immune cells that are the targets of HIV infection, making them responsive to the hyperdopaminergic environment that is characteristic of stimulant drugs. Therefore, the presence of high levels of dopamine may affect the pathogenesis of HIV, particularly in the brain. The stimulation of HIV latently infected U1 promonocytes with DA significantly increased viral p24 levels in the supernatant at 24 h, suggesting effects on activation and replication. Using selective agonists to different DRDs, we found that DRD1 played a major role in activating viral transcription, followed by DRD4, which increased p24 with a slower kinetic rate compared to DRD1. Transcriptome and systems biology analyses led to the identification of a cluster of genes responsive to DA, where S100A8 and S100A9 were most significantly correlated with the early increase in p24 levels following DA stimulation. Conversely, DA increased the expression of these genes' transcripts at the protein level, MRP8 and MRP14, respectively, which form a complex also known as calprotectin. Interestingly, MRP8/14 was able to stimulate HIV transcription in latent U1 cells, and this occurred via binding of the complex to the receptor for an advanced glycosylation end-product (RAGE). Using selective agonists, both DRD1 and DRD4 increased MRP8/14 on the surface, in the cytoplasm, as well as secreted in the supernatants. On the other hand, while DRD1/5 did not affect the expression of RAGE, DRD4 stimulation caused its downregulation, offering a mechanism for the delayed effect via DRD4 on the p24 increase. To cross-validate MRP8/14 as a DA signature with a biomarker value, we tested its expression in HIV+ Meth users' postmortem brain specimens and peripheral cells. MRP8/14+ cells were more frequently identified in mesolimbic areas such as the basal ganglia of HIV+ Meth+ cases compared to HIV+ non-Meth users or to controls. Likewise, MRP8/14+ CD11b+ monocytes were more frequent in HIV+ Meth users, particularly in specimens from participants with a detectable viral load in the CSF. Overall, our results suggest that the MRP8 and MRP14 complex may serve as a signature to distinguish subjects using addictive substances in the context of HIV, and that this may play a role in aggravating HIV pathology by promoting viral replication in people with HIV who use Meth.

Clinical trials of antiretroviral treatment interruption in HIV-infected individuals

: Despite the benefits of antiretroviral therapy (ART) for people living with HIV, there has been a long-standing research interest in interrupting ART as a strategy to minimize adverse effects of ART as well as to test interventions aiming to achieve a degree of virological control without ART. We performed a systematic review of HIV clinical studies involving treatment interruption from 2000 to 2017 to describe the differences between treatment interruption in studies that contained and didn't contain an intervention. We assessed differences in monitoring strategies, threshold to restart ART, duration and adverse outcomes of treatment interruption, and factors aimed at minimizing transmission. We found that treatment interruption has been incorporated into 159 clinical studies since 2000 and is increasingly being included in trials to assess the efficacy of interventions to achieve sustained virological remission off ART. Great heterogeneity was noted in immunological, virological and clinical monitoring strategies, as well as in thresholds to recommence ART. Treatment interruption in recent intervention studies were more closely monitored, had more conservative thresholds to restart ART and had a shorter treatment interruption duration, compared with older treatment interruption studies that didn't include an intervention.

CD38 Expression in a Subset of Memory T Cells Is Independent of Cell Cycling as a Correlate of HIV Disease Progression

In order to determine if the expression of the activation marker CD38 can correlate with HIV disease progression independently of cycling, we performed a cluster-based multivariate correlation analysis of total circulating CD4⁺ T cell counts and viral loads with frequencies of CD38 and Ki67 expression on CD4⁺ lymphocytes from patients with untreated HIV infection, stratified in maturation subpopulations, and subpopulation subsets defined by the expression of CXCR5, CXCR3, and CCR4. The frequencies of the activated phenotypes %CD38⁺ Ki67⁻ and %CD38⁺ Ki67⁺ of the CXCR5⁻ CXCR3⁻ CCR4⁺ (“pre-Th2”) central memory (T_CM) cell subset clustered together, comprising a significant negative correlate of total circulating CD4⁺ T cell counts and a positive correlate of viral load in multivariate analysis. Frequency of cycling-uncoupled CD38 expression in “pre-Th2” T_CM cells was a negative correlate of total circulating CD4⁺ T cell counts in univariate analysis, which was not the case of their %CD38⁺ Ki67⁺. CXCR5⁺ CXCR3⁻ CCR4⁻T_CM cells were underrepresented in patients, and their absolute counts correlated negatively with their %CD38⁺ Ki67⁻ but not with their % CD38⁺ Ki67⁺. Our results may imply that CD38 expression either reflects or participates in pathogenic mechanisms of HIV disease independently of cell cycling.

Is the central nervous system a reservoir of HIV-1?

PURPOSE OF REVIEW

To summarize the evidence in the literature that supports the central nervous system (CNS) as a viral reservoir for HIV-1 and to prioritize future research efforts.

RECENT FINDINGS

HIV-1 DNA has been detected in brain tissue of patients with undetectable viral load or neurocognitive disorders, and is associated with long-lived cells such as astrocytes and microglia. In neurocognitively normal patients, HIV-1 can be found at high frequency in these cells (4% of astrocytes and 20% of macrophages). CNS cells have unique molecular mechanisms to suppress viral replication and induce latency, which include increased expression of dominant negative transcription factors and suppressive epigenetic factors. There is also evidence of continued inflammation in patients lacking a CNS viral load, suggesting the production and activity of viral neurotoxins (for example, Tat).

SUMMARY

Together, these findings provide evidence that the CNS can potentially act as a viral reservoir of HIV-1. However, the majority of these studies were performed in historical cohorts (absence of combination antiretroviral therapy or presence of viral load), which do not reflect modern day patients (combination antiretroviral therapy-treated and undetectable viral load). Future studies will need to examine patient samples with these characteristics to conclusively determine whether the CNS represents a relevant and important viral reservoir.

Macrophages and their relevance in Human Immunodeficiency Virus Type I infection

Macrophages are important target cells for the Human Immunodeficiency Virus Type I (HIV-1) in vivo. Several studies have assessed the molecular biology of the virus in this cell type, and a number of differences towards HIV-1 infection of CD4+ T cells have been described. There is a broad consensus that macrophages resist HIV-1 infection much better than CD4+ T cells. Among other reasons, this is due to the presence of the recently identified host cell restriction factor SamHD1, which is strongly expressed in cells of the myeloid lineage. Furthermore, macrophages produce and release relatively low amounts of infectious HIV-1 and are less sensitive to viral cytotoxicity in comparison to CD4+ T cells. Nevertheless, macrophages play a crucial role in the different phases of HIV-1 infection. In this review, we summarize and discuss the significance of macrophages for HIV-1 transmission, the acute and chronic phases of HIV-1 infection, the development of acquired immunodeficiency syndrome (AIDS) and HIV-associated diseases, including neurocognitive disorders. We propose that interaction of HIV-1 with macrophages is crucial during all stages of HIV-1 infection. Thus, long-term successful treatment of HIV-1 infected individuals requires potent strategies to prevent HIV-1 from entering and persisting in these cells.

Identifying HIV infection in diagnostic histopathology tissue samples--the role of HIV-1 p24 immunohistochemistry in identifying clinically unsuspected HIV infection: a 3-year analysis

AIMS

Because of the clinical difficulty in identifying the early stages of human immunodeficiency virus (HIV) infection, the histopathologist often has to consider the diagnosis of HIV in tissue samples from patients with no previous suspicion of HIV infection. The aim was to investigate the practicality and utility of routine HIV-1 p24 immunohistochemistry on tissue samples received at a London histopathology laboratory.

METHODS AND RESULTS

Over a 3-year period, HIV-1 p24 was evaluated immunohistochemically on 123 cases. Of these, 37 (30%) showed positive expression of p24 in lesional follicular dendritic cells (FDCs). Of these 37 cases, 11 were not clinically suspected to be HIV+ and had no prior serological evidence of HIV infection. These cases represented lymph node biopsies, tonsillar and nasopharyngeal biopsies and a parotid excision. In addition to expression on FDCs, in 22 cases (60%), p24 also highlighted mononuclear cells and macrophages. p24 was also useful in confirming the presence of HIV in lymphoid tissue in non-lymphoid organs such as the lung, anus, salivary gland and brain. Immunonegativity occurred in occasional known HIV+ cases, probably related to treatment or tissue processing.

CONCLUSIONS

This study confirms the usefulness of this technique in detecting unsuspected HIV infection in lymphoid and non-lymphoid organs on histopathological material and should be part of routine evaluation of lymph nodes and lymphoid tissue in other organs if morphological or clinical features suggest HIV infection.

Evaluation of the pathogenesis of decreasing CD4(+) T cell counts in human immunodeficiency virus type 1-infected patients receiving successfully suppressive antiretroviral therapy

Most human immunodeficiency virus (HIV)-infected individuals experience increases in peripheral CD4(+) T cell counts with suppressive antiretroviral therapy (ART) that achieves plasma HIV RNA levels that are less than the limit of detection. However, some individuals experience decreasing CD4(+) T cell counts despite suppression of plasma viremia. We evaluated 4 patients with a history of CD4(+) T cell decline despite successfully suppressive ART, from a median of 719 cells/mm(3) (range, 360-1141 cells/mm(3)) to 227 cells/mm(3) (range, 174-311 cells/mm(3)) over a period of 18-24 months; 3 of the patients were receiving tenofovir and didanosine, which may have contributed to this decrease. There was no evidence of HIV replication, nor of antiretroviral drug resistance in the blood or lymphoid tissue, or increased proliferation or decreased thymic production of naive CD4(+) T cells. All 4 patients had significant fibrosis of the T cell zone of lymphoid tissue, which appeared to be an important factor in the failure to reconstitute T cells.

Prognostic factors of long-term CD4+count-guided interruption of antiretroviral treatment

Aim of the study was to determine predictors of the duration of antiretroviral treatment interruption in patients infected with HIV. This pilot prospective, open-label, multicenter trial comprised 62 HIV-seropositive subjects who decided voluntarily to interrupt therapy after two or more years of successful HAART. The primary end-point was the time to patients being free of therapy before reaching a CD4+ cell count < or =350/microl. Fifteen of 62 patients remained in treatment interruption for more than 180 days. Patients restarting therapy had higher HIV-DNA levels (P = 0.05), were treated more frequently with NNRTI-drugs (P = 0.02), had a shorter period of HAART (P = 0.046), and lower CD4+ cell counts after day 14 of interruption of treatment (P = 0.04). Multivariate regression analysis showed that less than 323 baseline proviral HIV-DNA cp/10(6) PBMCs and more than 564 CD4 cells/microl at day 14 after interruption were associated independently with a reduced risk of restarting treatment (P = 0.041 and P = 0.012, respectively). A score based on CD4+ cell counts at nadir, at baseline, at week 2 of treatment interruption, and on baseline HIV-DNA values can identify patients with a prolonged period free safely of treatment.

Biphasic decay kinetics suggest progressive slowing in turnover of latently HIV-1 infected cells during antiretroviral therapy

Background

Mathematical models based on kinetics of HIV-1 plasma viremia after initiation of combination antiretroviral therapy (cART) inferred HIV-infected cells to decay exponentially with constant rates correlated to their strength of virus production. To further define in vivo decay kinetics of HIV-1 infected cells experimentally, we assessed infected cell-classes of distinct viral transcriptional activity in peripheral blood mononuclear cells (PBMC) of five patients during 1 year after initiation of cART

Results

In a novel analytical approach patient-matched PCR for unspliced and multiply spliced viral RNAs was combined with limiting dilution analysis at the single cell level. This revealed that HIV-RNA⁺ PBMC can be stratified into four distinct viral transcriptional classes. Two overlapping cell-classes of high viral transcriptional activity, suggestive of a virion producing phenotype, rapidly declined to undetectable levels. Two cell classes expressing HIV-RNA at low and intermediate levels, presumably insufficient for virus production and occurring at frequencies exceeding those of productively infected cells matched definitions of HIV-latency. These cells persisted during cART. Nevertheless, during the first four weeks of therapy their kinetics resembled that of productively infected cells.

Conclusion

We have observed biphasic decays of latently HIV-infected cells of low and intermediate viral transcriptional activity with marked decreases in cell numbers shortly after initiation of therapy and complete persistence in later phases. A similar decay pattern was shared by cells with greatly enhanced viral transcriptional activity which showed a certain grade of levelling off before their disappearance. Thus it is conceivable that turnover/decay rates of HIV-infected PBMC may be intrinsically variable. In particular they might be accelerated by HIV-induced activation and reactivation of the viral life cycle and slowed down by the disappearance of such feedback-loops after initiation of cART.

Lymph node architecture collapse and consequent modulation of FOXO3a pathway on memory T- and B-cells during HIV infection

Lymph nodes (LNs) represent the principal site where antigen-specific memory T- and B-cell responses are primed and differentiated into memory and effector cells. During chronic viral infections such as HIV, these lymphoid tissues undergo substantial structural changes. These changes are mostly caused by an imbalanced cytokine milieu, hyper-immune activation and collagen deposition leading to fibrotic LNs. The structural integrity of the LNs is essential to prime and maintain memory responses. Because cellular signalling events both up- and down-stream of FOXO3a are critical to the generation and the maintenance of lymphocyte memory, this review will focus on the interplay between the deregulation of the immune system caused by the virus and its impact on FOXO3a.

The potential of topical DNA vaccines adjuvanted by cytokines

To improve the efficacy of DNA immunization epidermal Langerhans cells are attractive targets to deliver antigen-encoding plasmid DNA. Topical vaccination with naked plasmid DNA has been shown to induce immune responses, and their potency might be improved by chemical and physical methods aimed to enhance the efficiency of plasmid DNA delivery into the skin. Cytokines have also been evaluated as adjuvants for DNA vaccines because they influence the host immune response. This review focuses on the action of several cytokines tested as molecular adjuvants for DNA vaccines and the combination of them with the DermaVir Patch vaccine. DermaVir vaccine, topically administered under a patch, consists of a plasmid DNA that is chemically formulated into a nanoparticle to support vaccine delivery into epidermal Langerhans cells and to induce antigen-specific memory T cells.

Discovery of Human Immunodeficiency Virus Infection by Immunohistochemistry on Lymph Node Biopsies From Patients With Unexplained Follicular Hyperplasia

Over the last 10 years, 240 cases of hyperplasic lymphadenitis have been systematically tested in our institution for the presence of the human immunodeficiency virus (HIV). This series comprised patients between 15 and 90 years (median of age: 38.51) without a past history of HIV infection. The technical approach consisted in an immunohistochemical procedure with a monoclonal antibody against the p24-gag protein of HIV. Among the 240 cases, 105 had a true follicular hyperplasia. Overall, this survey found that 4 cases (3 males and 1 female) were positive for p24-gag without previous knowledge of HIV infection (4/240=1.66%). HIV infection was further confirmed by serologic and molecular investigations in all cases. These results were seen exclusively in those cases with prominent follicular hyperplasia (4/105=3.80%). Staining with the anti-p24 antibody was intense and restricted to the follicular dendritic cell networks. In one case, beside hyperplasic germinal centers, one could see a regressed onion bulblike structure. One important conclusion can be drawn from this study. A systematic research of HIV proteins should be performed in all lymph node biopsies with marked follicular hyperplasia, in a context of polyadenopathy, fever, and general status alteration. Besides giving an accurate diagnosis, this approach may be helpful in cases of recent infection in which anti-p24 antibodies are not yet detectable in the serum.

Fluorodeoxyglucose imaging in healthy subjects with HIV infection: impact of disease stage and therapy on pattern of nodal activation

OBJECTIVES

Nodal uptake in areas of lymphocyte activation can be visualized using fluorodeoxyglucose. Various patterns of fluorodeoxyglucose accumulation in HIV-positive patients have been described previously and hypothesized potentially to represent regions of active HIV replication or nodal activation. We evaluated the utility of fluorodeoxyglucose scanning as a tool to study HIV pathogenesis.

DESIGN

We evaluated fluorodeoxyglucose biodistribution visually and quantitatively in HIV-negative individuals and various groups of HIV-infected patients to determine the impact on the pattern of nodal activation of HIV infection, the stage of HIV infection and degree of viremia, and HAART. In addition, we attempted to image anatomical site(s) of ongoing HIV replication in patients with suppressed HIV viremia on HAART, but subsequently discontinued HAART.

METHOD

We performed fluorodeoxyglucose imaging on five groups: HIV-negative, HIV-positive individuals with early infection, HIV-positive patients with advanced disease, HIV-positive patients with suppressed viral loads, and HIV-positive patients who stopped HAART.

RESULTS

Healthy HIV patients with suppressed viral loads and HIV-negative individuals had no or little fluorodeoxyglucose nodal accumulation or any other hypermetabolic areas, whereas viremic individuals with early and advanced HIV had increased fluorodeoxyglucose in the peripheral nodes, indicating that fluorodeoxyglucose potentially identifies areas of HIV replication. Fluorodeoxyglucose biodistribution was similar between early and advanced-stage disease. Four of five patients taken off HAART had negative baseline scans but developed nodal uptake and increases in viral loads.

CONCLUSION

Abnormal fluorodeoxyglucose accumulation occurs in the nodes of individuals with detectable viral loads. Interruption of effective HAART results in the activation of previously quiescent nodal areas.

Fluorodeoxyglucose imaging in healthy subjects with HIV infection: impact of disease stage and therapy on pattern of nodal activation

OBJECTIVES

Nodal uptake in areas of lymphocyte activation can be visualized using fluorodeoxyglucose (FDG). Various patterns of FDG accumulation in HIV-positive subjects have been described previously and hypothesized to potentially represent regions of active HIV replication and or nodal activation. We evaluated the utility of FDG scanning as a tool to study HIV pathogenesis.

DESIGN

We evaluated FDG biodistribution visually and quantitatively in HIV-negative individuals and various groups of HIV-infected subjects to determine the impact on pattern of nodal activation of: HIV infection; stage of HIV infection and degree of viremia; and HAART. In addition, we attempted to image anatomical site(s) of on-going HIV replication in subjects with suppressed HIV viremia on ART, but who subsequently discontinued ART.

METHOD

We performed FDG imaging on five groups: HIV-negative, HIV-positive with early infection, HIV-positive with advanced disease, HIV-positive with suppressed viral loads, and HIV-positive who stopped ART.

RESULTS

Healthy HIV subjects with suppressed viral loads and HIV-negative individuals had no or little FDG nodal accumulation or any other hypermetabolic areas, whereas viremic subjects with early and advanced HIV had increased FDG in peripheral nodes, indicating that FDG potentially identifies areas of HIV replication. FDG biodistribution was similar between early and advanced-stage. Four of five subjects taken off ART had negative baseline scans but developed nodal uptake and increases in viral load.

CONCLUSIONS

Abnormal FDG accumulation occurs in nodes of subjects with detectable viral loads. Interruption of effective ART results in activation of previously quiescent nodal areas.

Cell cycle kinetic dysregulation in HIV-infected normal lymphocytes

BACKGROUND

Viruses alter cellular gene transcription and protein binding at many steps critical for cell cycle regulation to optimize the milieu for productive infection. Reasoning that virus-host cell interactions would result in perturbations of cell cycle kinetics, measurement of the duration of the phases of the cell cycle in normal T lymphocytes infected with human immunodeficiency virus (HIV) was undertaken.

METHODS

Flow cytometric measurement of bromodeoxyuridine-labeled and DNA content-stained cells at multiple points through the cell cycle allowed estimation of the fraction of cells in each phase, the potential doubling-time, and the durations of S and G(2)/M phases. Separate analysis of the HIV(+) and HIV(-) populations within the infected cultures was performed based on intracellular, anti-HIV core p24 antibody labeling. A novel mathematical model, which accounted for cell loss, was developed to estimate cell cycle phases.

RESULTS

(a) S phase was prolonged in the HIV-1(SF2)-infected cells compared with control. (b) This delay in S phase was due to delay in the population of cells not expressing HIV-1 antigens (p24 negative). (c) Accumulation of cells in G(2)/M phase was confirmed in HIV-1-infected cultures and was proportional to the level of infection as measured by p24 fluorescent intensity. However, all mock and HIV-1-infected populations predicted to proceed through cell division demonstrated similar G(2)/M-phase durations. (c) Potential doubling times were longer in the infected cultures; in contrast, the p24(+) subpopulations accounted for this delay. This suggests an isolated delay in the G(0)/G(1) phase for that population of cells.

CONCLUSIONS

Multiple phases of host cell cycle durations were affected by HIV-1(SF2) infection in this in vitro model, suggesting novel HIV-1 pathogenesis mechanisms. Prolonged S-phase durations in HIV-1 infected/p24(-) and G(0)/G(1)-phase durations in HIV-1 infected/p24(+) subpopulations require further study to identify mechanistic pathways.

Current status of gene therapy strategies to treat HIV/AIDS

Progress in developing effective gene transfer approaches to treat HIV-1 infection has been steady. Many different transgenes have been reported to inhibit HIV-1 in vitro. However, effective translation of such results to clinical practice, or even to animal models of AIDS, has been challenging. Among the reasons for this failure are uncertainty as to the most effective cell population(s) to target, the diffuseness of these target cells in the body, and ineffective or insufficiently durable gene delivery. Better understanding of the HIV-1 replicative cycle, host factors involved in HIV-1 infection, vector biology and application, transgene technology, animal models, and clinical study design have all contributed vastly to planning current and future strategies for application of gene therapeutic approaches to the treatment of AIDS. This review focuses on the newest developments in these areas and provides a strong basis for renewed optimism that gene therapy will have an important role to play in treating people infected with HIV-1.

Biphasic decline of CD4 cell count during scheduled treatment interruptions

In 115 patients whose scheduled treatment interruptions (STI) lasted 24 weeks, the CD4 cell count declined by a median of 30 cells/ml/week during the first 4 weeks, compared with 3 cells/ml/week during the next 20 weeks. In multivariate regression, a pronounced early fall in CD4 cells correlated with a higher CD4 cell count at the start of STI, with more gain in CD4 cells during antiretroviral treatment preceding STI, and with a higher viral load at week 4.

Changes in CD4+ T-cell differentiation phenotype during structured treatment interruption in patients with chronic HIV-1 infection

Markers of maturation and activation were measured on peripheral CD4+ T cells in chronically HIV-1-infected patients in a randomized, controlled pilot study of structured treatment interruption (STI). Eight subjects underwent 2 cycles of 1 month off and 1 month on highly active antiretroviral therapy (HAART), followed by a final 3-month interruption. During STI, CD4+ T-cell percentage remained relatively stable in 4 of 8 subjects. The remaining 4 STI subjects had significant rapid decline in CD4+ T-cell percentage during STI, followed by return to pre-STI baseline while on HAART. Changes in overall CD4+ T-cell percentage corresponded with fluctuations in the CD45RA+CCR7+ naive and CD45RA-CCR7+ central memory subsets. Subjects with variable CD4+ T-cell percentages tended to have higher pre-HAART plasma HIV-1 RNA set-points and experienced higher levels of plasma HIV-1 RNA rebound during STI. These results suggest that interruptions should be avoided whenever possible in patients on HAART with high plasma HIV-1 RNA set-points.

Dissociation of CD4+ cell counts from viral load and association with immune complexes in HIV+ hemophilia patients

OBJECTIVE

We have postulated that the host autoimmune response regulates and mediates CD4 depletion during HIV infection by opsonization of circulating CD4(+) lymphocytes carrying autoreactive immune complexes (IC) consisting of complement-fixing IgM and IgG, and during advanced stages of HIV disease of IgM/ IgG/gp120 complexes. In this retrospective study, we investigated whether HIV causes CD4 depletion by direct cytotoxicity or indirectly by induction of a host autoimmune response.

PATIENTS AND METHODS

In 1996, 12 HIV(+) hemophilia patients were converted to highly active antiretroviral therapy (HAART), while 10 other patients were maintained on conventional antiretroviral treatment and another 11 patients refused to be treated with antiretroviral drugs. The host immune response of these 33 HIV(+) patients was studied during the periods of minimum viral replication (Interval 1), subsequent rise in viral replication with strong replication dynamic (Interval 2), and maximum viral replication (Interval 3). The patients were categorized into three groups according to viral load (VL). Group A: patients with low level VL (n=10) showed a modest increase from <80 to <4 log 10 HIV-1 RNA copies per milliliter plasma during the observation period; Group B: patients with medium level VL (n=12) showed a stronger increase from <80 to >4 log 10 copies per milliliter plasma; and Group C: patients with high level VL (n=11) consistently had a median of >4 log 10 copies per milliliter plasma, during Intervals 1-3, with the exception of one patient who during Interval 2 had 4800 copies per milliliter. Blood lymphocyte subpopulations, proportions of CD4(+) blood lymphocytes coated with IgM, IgG, C3d and/or gp120, in vitro responses to mitogens and pooled allogeneic stimulator cells, as well as numbers of HIV-1 RNA copies per milliliter plasma were measured.

RESULTS

Sequential analysis of VL, IC load on CD4(+) blood lymphocytes and CD4 counts showed that an increasing VL was not associated with CD4 depletion, when the proportion of IC-coated circulating CD4(+) blood lymphocytes remained stable. When, CD4 counts and IC load were analyzed during corresponding intervals of retroviral replication in the three patient groups, a higher VL was associated with lower CD4 counts only when the IC load (IgG or gp120/IgG) on CD4(+) lymphocytes was higher as well.

CONCLUSION

These data suggest that HIV regulates and mediates CD4 depletion in part by the induction of autoreactive ICs against CD4(+) lymphocytes, especially complement-fixing autoreactive IgG and gp120/IgG complexes.

Phase I trial of a therapeutic HIV type 1 vaccine, Vacc-4x, in HIV type 1-infected individuals with or without antiretroviral therapy

Highly active antiretroviral therapy (HAART) can effectively suppress HIV-1 replication but, as soon as the drugs are withdrawn, there is a rapid rebound of replicating virus. Severe metabolic toxicities and therapy failures due to the appearance of resistant virus are becoming an increasing problem that precludes long-term continuous medication. Therapeutic immunizations represent a feasible and attractive means of supplementing or, alternatively, replacing current therapies, thereby reducing the potential for emergence of drug-resistant HIV-1 strains. We have performed an open, single-center, phase I safety study of a candidate therapeutic HIV-1 vaccine, Vacc-4x, given to 11 HIV-1-infected individuals with or without antiretroviral therapy. The immunogen consists of four synthetic peptides based on the major core protein p24. To ensure optimal exposure of the immunogen to the antigen-presenting cells (APCs), the vaccine was given intradermally together with granulocyte-macrophage colony-stimulating factor (GM-CSF). Responses to the immunization protocol were determined by delayed-type hypersensitivity (DTH) reaction, interferon gamma-secreting cells in the enzyme-linked immunospot (ELISpot) assay, and antibody production to the p24 protein and the peptides. The vaccine was safe and in general well tolerated. Plasma HIV RNA levels and CD4(+) cell counts did not change appreciably during the study. All patients showed a positive DTH response. For two of the patients, the immunization protocol induced responses to one or two of the tested peptides whereas a third patient showed reactivity to one of the peptides before immunization. A weak antibody response in the peptide-specific enzyme-linked immunosorbent assay could be seen in seven patients.

Matrix fibronectin increases HIV stability and infectivity

HIV particles are detected extracellularly in lymphoid tissues, a major reservoir of the virus. We previously reported that a polymerized form of fibronectin (FN), superfibronectin (sFN), as well as a fragment of FN, III1-C, enhanced infection of primary CD4(+) T cells by HIV-1IIIB. We now show that sFN enhances infection of primary CD4(+) T cells by both R5 and X4 strains of HIV-1. Using HIV pseudotyped with different envelope glycoproteins (gp120) and HOS cells transfected with various chemokine receptors alone or in combination with the CD4 molecule, we show that sFN-mediated enhancement requires the CD4 receptor and does not alter the specificity of gp120 for different chemokine receptors. Because the III1-C fragment also resulted in enhancement, we asked whether proteolysis of FN generated fragments capable of enhancing HIV infection. We found that progressive proteolysis of FN by chymotrypsin correlates with an enhancement of HIV infection in both primary CD4(+) T cells and the IG5 reporter cell line. Furthermore, incubation of HIV with sFN significantly prolonged infectivity at 37 degrees C compared with dimeric FN or BSA. In conclusion, these results indicate that polymerized (matrix) or degraded (inflammation-associated), but not dimeric (plasma), FN are capable of enhancing infection by HIV-1, independent of the coreceptor specificity of the strains. Moreover, virions bound to matrix FN maintain infectivity for longer periods of time than do virions in suspension. This study suggests that matrix proteins and their conformational status may play a role in the pathogenesis of HIV.

Recovery of replication-competent HIV type 1-infected circulating monocytes from individuals receiving antiretroviral therapy

The affect of antiretroviral therapy (ART) on HIV-1 recovery from blood monocytes was determined in purified peripheral blood monocyte-derived macrophage (MDM) cultures from HIV-1-infected subjects with undetectable plasma viremia or active viral replication. Additionally, the association between replication-competent HIV-1-infected MDM and neurocognitive status was examined. Fifty-two individual with previous AIDS-defining illnesses receiving nucleoside analogues with and without protease inhibitors or no ART were followed for up to 1.5 years. Detection of plasma viremia significantly correlated with the occurrence of infected monocytes. Viral replication was detected in less than 10% of the MDM cultures from 23 individuals receiving effective antiretroviral therapy. In contrast, approximately 50% of the MDM cultures from 29 individuals with active viral replication and evidence of decreased immune function, including all individuals with neurocognitive impairment, produced detectable virus indicating that a lack of adequate ART results in increased abundance of replication-competent blood monocytes. Proviral DNA levels were a minimum of 13-fold higher in MDM from subjects with active viral replication. The infrequent detection of viral DNA in cultures from individuals receiving effective ART suggested low levels of circulating monocytes harboring replication-incompetent virus. These studies demonstrate that HIV-infected individuals on ART with breakthrough viremia have significantly higher levels of circulating infected monocytes, the precursors of tissue macrophages.

Plasma levels of soluble CD27: a simple marker to monitor immune activation during potent antiretroviral therapy in HIV-1-infected subjects

Plasma levels of soluble CD27 (sCD27) are elevated in diseases characterized by T cell activation and are used as a marker of immune activation. We assessed the usefulness of determining plasma sCD27 as a marker for monitoring immune activation in HIV-1-infected patients treated with highly active antiretroviral therapy (HAART). A first cross-sectional examination of 68 HIV-1-infected and 18 normal subjects showed high levels of sCD27 in HIV-1 infection; plasma sCD27 was correlated to HIV-1 viraemia and inversely correlated to CD4+ T cell count. Twenty-six HIV-1-infected patients undergoing HAART were studied at baseline and after 6, 12, 18 and 24 months of therapy. Seven additional patients under HAART were analysed at baseline, during and after interruption of therapy. In the total population, HAART induced a significant and progressive reduction, but not a normalization, of plasma levels of sCD27 after 24 months. A full normalization of plasma sCD27 was observed in the virological responders (undetectable HIV-1 RNA at months 18 and 24) and also in patients with moderate immunodeficiency at baseline (CD4+ T cell count >200 cells/mm3). Changes in plasma neopterin paralleled the changes in sCD27 but only baseline sCD27 levels were predictive of a greater increase in CD4+ T cell count during the follow-up. Discontinuation of therapy resulted in a rapid increase of sCD27 plasma levels associated with viraemia rebound and drop in CD4+ T cell count. Our findings suggest that plasma sCD27 may represent an alternative and simple marker to monitor immune activation during potent antiretroviral therapy. HIV-1-induced immune activation can be normalized by HAART in successfully treated patients where the disease is not advanced.

Structured treatment interruptions in HIV/AIDS therapy

Structured treatment interruption (STI) has been investigated for three distinct clinical scenarios: during acute infection with the goal of immune reconstitution and auto immunization; during chronic infection, to decrease the amount and toxicity of antiretroviral drugs; and during virologic failure to restore response to subsequent antiretroviral therapy. The potential costs and benefits of STI should be determined.

Cerebrospinal fluid response to structured treatment interruption after virological failure

OBJECTIVE

Structured antiretroviral treatment interruption (STI) has been advocated as a therapeutic strategy for HIV-1 infection. We report initial observations of cerebrospinal fluid (CSF) HIV-1 infection in five patients undergoing serial lumbar punctures (LPs) during STI undertaken following virological failure.

DESIGN AND METHODS

In this prospective observational study we quantified HIV-1 RNA concentrations and assessed both phenotypic drug susceptibility profiles and genotypic antiviral drug resistance mutations in CSF and plasma during the period of treatment interruption. CSF white blood cells were also counted, and patients' neurological status monitored.

RESULTS

In four of the patients, CSF HIV-1 concentration increased more rapidly than that of the plasma, with consequent reduction in the ratio between plasma and CSF viral loads (pVL : cVL). Three individuals developed robust, though asymptomatic CSF lymphocytic pleocytosis. In all patients the predominant HIV-1 quasispecies shifted simultaneously in CSF and plasma from a drug-resistant to a more drug-susceptible phenotype with identical and simultaneous changes in genotypes associated with drug resistance.

CONCLUSIONS

STI may be accompanied by previously unrecognized changes in tissue viral exposures and lymphocyte traffic. Hence, despite 'virological failure' as evidenced by persistent plasma viremia, ongoing antiretroviral treatment prior to its interruption appeared to suppress CSF HIV-1 infection (indeed more effectively than that of plasma) and restrain lymphocyte traffic into the CSF. Simultaneous change of resistance mutations in CSF and plasma was likely due to re-emergence and overgrowth of pre-existing strains with ready exchange of virus between these two compartments, either facilitated by or provoking a local CSF lymphocytosis.

The failure of HAART to cure the HIV-1/AIDS complex. Suggestions to add integrase inhibitors as complementary virostatics, and to replace their continuous long combination applications by short sequences differing by drug rotations

While the intensive virostatic combinations applied according to the conventional models (such as HAART), based only on the attacks of two HIV-1 targets, retrotranscriptase and protease, and applied in a long and continuous fashion, a) are notably toxic, b) do not correct completely the abnormal immunologic parameters, and c) are followed by particularly severe and poorly sensitive relapses in case of discontinuation, we propose to the 'AIDS treatment headquarters' to include in their failing strategy the two original features which we have included in the treatment of a cohort of a dozen patients, treatment applied at all but one AIDS stage. We attack one more HIV-1 target than the conventional protocols do, by adding inhibitors of integrase; we apply the combinations of virostatics, comprising inhibitors of the three targets, in short sequences (of 3 weeks), between which the analogues are changed inside each series. The first patient of the cohort started his treatment 8.5 years ago, and the entries of the others into it have been at random and not randomized. All patients are alive today and in excellent condition.

Current review and clinical management of patients with primary HIV-1 infection: limits and perspectives

Acute primary HIV-1 infection (PHI) remains underestimated or misdiagnosed in clinical practice. Meanwhile, it has been demonstrated that early therapeutic interventions with highly active antiretroviral therapy (HAART) may delay disease progression and possibly preserve and expand the most effective immune effector T-cells against HIV together with the humoral immune responses. Since long-life HAART is an unachievable goal due to long-term toxicity and risk of occurrence of resistant strains due to a decreased compliance or other still undefined host factors, preliminary data of programmed treatment interruption in patients treated for PHI suggest that a significant number (30-50%) could benefit from long periods off therapy. However, in more than half of them, the viral load will rebound, justifying that treatment be reinitiated. In order to reduce this proportion, new options are currently being investigated, including adjunctive immune therapy to HAART such as cytokines or vaccines, which could tackle the viral rebounds by increasing HIV-specific cellular responses. An update on the management of patients with PHI is reviewed and the limits of the current standard of care are discussed.

Structured treatment interruptions in antiretroviral management of HIV-1

The consequences of treatment interruptions have been investigated in various patient populations. For patients with controlled viraemia, treatment interruption allowing viral rebound may boost HIV-1-specific immunity. The hypothesis that this will be sufficient to control HIV replication in the absence of treatment has received support in studies of patients initiating treatment during primary infections. In patients with chronic infection, treatment interruption has been shown to boost HIV-1-specific immunity in some cases. In patients with virological failure, despite drug-resistant virus, treatment appears to provide benefit, in that interruption results in a decrease in the CD4 cell count and increases in plasma HIV-1-RNA levels. The removal of drug pressure allows the rapid shift to wild-type virus. Whether this will be of benefit to the patient is not clear. Treatment interruption may help reduce the accumulation of long-term toxicities.

Structured treatment interruptions to control HIV-1 and limit drug exposure

Although therapy-mediated suppression of HIV-1 is effective and results in a degree of immune reconstitution, the complications resulting from life-long treatment emphasize the need for alternatives. This review discusses the use of structured interruptions in antiviral therapy to induce drug-free periods of immune-mediated control of HIV-1. Such an approach has the ultimate objective of harnessing anti-viral immune responses, reducing drug exposure (toxicity and cost) and potentially extending the clinical benefits of a suppressive treatment regimen.