CD38 expression in CD8+ T cells predicts virological failure in HIV type 1-infected children receiving antiretroviral therapy

Dual impact: CD38 inhibition in glycolysis and oxidative phosphorylation

CD38 negatively impacts T-cell metabolic phenotypes

CD38: An important regulator of T cell function

Cluster of differentiation 38 (CD38) is a multifunctional extracellular enzyme on the cell surface with NADase and cyclase activities. CD38 is not only expressed in human immune cells, such as lymphocytes and plasma cells, but also is abnormally expressed in a variety of tumor cells, which is closely related to the occurrence and development of tumors. T cells are one of the important immune cells in the body. As NAD consuming enzymes, CD38, ART2, SIRT1 and PARP1 are closely related to the number and function of T cells. CD38 may also influence the activity of ART2, SIRT1 and PARP1 through the CD38-NAD⁺ axis to indirectly affect the number and function of T cells. Thus, CD38-NAD⁺ axis has a profound effect on T cell activity. In this paper, we reviewed the role and mechanism of CD38⁺ CD4⁺ T cells / CD38⁺ CD8⁺ T cells in cellular immunity and the effects of the CD38-NAD⁺ axis on T cell activity. We also summarized the relationship between the CD38 expression level on T cell surface and disease prediction and prognosis, the effects of anti-CD38 monoclonal antibodies on T cell activity and function, and the role of anti-CD38 chimeric antigen receptor (CAR) T cell therapy in tumor immunity. This will provide an important theoretical basis for a comprehensive understanding of the relationship between CD38 and T cells.

Multi-Omics Profiling Identifies Pathways Associated With CD8+ T-Cell Activation in Severe Aplastic Anemia

Severe aplastic anemia (SAA) is an autoimmune disease characterized by immune-mediated destruction of hematopoietic stem and progenitor cells. Autoreactive CD8⁺ T cells have been reported as the effector cells; however, the mechanisms regulating their cell activation in SAA remain largely unknown. Here, we performed proteomics and metabolomics analyses of plasma and bone marrow supernatant, together with transcriptional analysis of CD8⁺ T cells from SAA patients and healthy donors, to find key pathways that are involved in pathogenic CD8⁺ T-cell activation. We identified 21 differential proteins and 50 differential metabolites in SAA patients that were mainly involved in energy metabolism, complement and coagulation cascades, and HIF-1α signaling pathways. Interestingly, we found that these pathways are also enriched in T cells from SAA patients by analyzing available single-cell RNA sequencing data. Moreover, CD8⁺ T cells from SAA patients contain a highly activated CD38⁺ subset, which was increased in the bone marrow of SAA patients and a murine model of SAA. This subset presented enriched genes associated with the glycolysis or gluconeogenesis pathway, HIF-1α signaling pathway, and complement associated pathways, all of which were of importance in T-cell activation. In conclusion, our study reveals new pathways that may regulate CD8⁺ T-cell activation in SAA patients and provides potential therapeutic targets for SAA treatment.

Myeloid-derived suppressor cells and the pathogenesis of human immunodeficiency virus infection

There are several mechanisms by which human immunodeficiency virus (HIV) can mediate immune dysfunction and exhaustion during the course of infection. Chronic immune activation, after HIV infection, seems to be a key driving force of such unwanted consequences, which in turn worsens the pathological status. In such cases, the immune system is programmed to initiate responses that counteract unwanted immune activation, for example through the expansion of myeloid-derived suppressor cells (MDSCs). Although the expansion of immune suppressor cells in the setting of systemic chronic immune activation, in theory, is expected to contain immune activation, HIV infection is still associated with a remarkably high level of biomarkers of immune activation. Paradoxically, the expansion of immune suppressor cells during HIV infection can suppress potent anti-viral immune responses, which in turn contribute to viral persistence and disease progression. This indicates that HIV hijacks not only immune activation but also the immune regulatory responses to its advantage. In this work, we aim to pave the way to comprehend how such unwanted expansion of MDSCs could participate in the pathology of acute/primary and chronic HIV infection in humans, as well as simian immunodeficiency virus infection in rhesus macaques, according to the available literature.

Virological failure and associated factors among children receiving anti-retroviral therapy, Northwest Ethiopia

BACKGROUND

Virological failure is under-recognized issue among children living with human immunodeficiency virus in developing countries. This partly may lead to failure to achieve the global goal of 90-90-90 targets in most developing countries including Ethiopia.

OBJECTIVES

This study aimed to assess the virological failure and its predictors among children receiving antiretroviral therapy at the University of Gondar comprehensive specialized hospital, Northwest Ethiopia.

METHODS

An institutional based cross-sectional study was conducted among 253 study cohorts from January 2020-April 2021. Socio-demographic characteristics were collected using a structured questionnaire via a face-to-face interview, while detailed clinical data of the children were collected by reviewing the medical record. About 5 ml of blood were collected for the analysis of complete blood count and viral load quantification. Data were analyzed using SPSS version 20 and variables at p-value < 0.05 in the multivariable analysis were considered as statistically significant.

RESULTS

In this study, the viral load suppression rate among antiretroviral therapy experienced children was 68.8%. Meanwhile, the overall virological failure among study participants was 19.4%. Children living without family (AOR = 3.63; 95%CI: 1.27-10.24), children with unemployed family (AOR = 4.95; 95%CI: 1.74-14.12), being wasted (AOR = 3.02; 95%CI: 1.19-7.67) being stunted (AOR = 2.38;95%CI:1.03-5.46), anemia (AOR = 5.50:95%CI;1.37-22.04) and being lymphopenic (AOR = 2.69:95%CI;1.04-7.75) were significantly associated with virological failure among children under treatment.

CONCLUSION

Higher virological failure among children was noteworthy in the present study. Caretakers other than immediate family, unemployed family, wasted, stunted, anemia, and lymphopenia were significant independent predictors of virological failure. Hence, standard, and optimal management of children under treatment should be warranted.

A Therapeutic Strategy to Combat HIV-1 Latently Infected Cells With a Combination of Latency-Reversing Agents Containing DAG-Lactone PKC Activators

Advances in antiviral therapy have dramatically improved the therapeutic effects on HIV type 1 (HIV-1) infection. However, even with potent combined antiretroviral therapy, HIV-1 latently infected cells cannot be fully eradicated. Latency-reversing agents (LRAs) are considered a potential tool for eliminating such cells; however, recent in vitro and in vivo studies have raised serious concerns regarding the efficacy and safety of the "shock and kill" strategy using LRAs. In the present study, we examined the activity and safety of a panel of protein kinase C (PKC) activators with a diacylglycerol (DAG)-lactone structure that mimics DAG, an endogenous ligand for PKC isozymes. YSE028, a DAG-lactone derivative, reversed HIV-1 latency in vitro when tested using HIV-1 latently infected cells (e.g., ACH2 and J-Lat cells) and primary cells from HIV-1-infected individuals. The activity of YSE028 in reversing HIV-1 latency was synergistically enhanced when combined with JQ1, a bromodomain and extra-terminal inhibitor LRA. DAG-lactone PKC activators also induced caspase-mediated apoptosis, specifically in HIV-1 latently infected cells. In addition, these DAG-lactone PKC activators showed minimal toxicity in vitro and in vivo. These data suggest that DAG-lactone PKC activators may serve as potential candidates for combination therapy against HIV-1 latently infected cells, especially when combined with other LRAs with a different mechanism, to minimize side effects and achieve maximum efficacy in various reservoir cells of the whole body.

Effect of chemoradiotherapy on the proportion of circulating lymphocyte subsets in patients with limited-stage small cell lung cancer

OBJECTIVE

Chemoradiotherapy (CRT) is the standard treatment for limited-stage small cell lung cancer (LS-SCLC), which can exert anti-tumor effects by regulating immune cells. Different immune cell subsets are associated with a specific sensitivity to CRT. The purpose of this study was to characterize the proportion or composition of peripheral lymphocytes in patients with LS-SCLC before and after CRT, and evaluate their prognostic value.

METHODS

A total of 98 patients with LS-SCLC were enrolled. The expression of CD3, CD4, CD8, CD45RA, CD45RO, CD38, CD56, and CD19 on the surface of peripheral blood cells was detected by flow cytometry and retrospectively analyzed. The relationship between the proportion of lymphocyte subsets, progression-free survival (PFS), and overall survival (OS) was evaluated using a log-rank test and Cox regression model.

RESULTS

The median PFS was 12.3 months and the median OS was 21.7 months. Compared with the pre-treatment specimens, post-treatment lymphocytes had increased proportions of CD3⁺, CD3⁺CD8⁺, CD8⁺CD38⁺ T cells, and NKT cells, and a decreased proportion of CD3⁺CD4⁺ T cells, CD4⁺CD45RA⁺ T cells, B cells, NK cells, and CD4/CD8 ratio. Univariate and multivariate analyses showed that prophylactic cranial irradiation, high percentages of CD4⁺CD45RA⁺, CD8⁺CD38⁺ T cells after CRT independently predicted superior PFS. Male patients with a high baseline CD4⁺CD45RO⁺ T cell ratio predicted a poor OS.

CONCLUSIONS

CRT induced changes in the proportion of circulating lymphocyte subsets in LS-SCLC, which is helpful for designing a regimen of immune drugs to be combined with CRT. The prognostic value of the proportion of lymphocytes aids in understanding the role of peripheral immune profiles in LS-SCLC.

Association of intestinal and systemic inflammatory biomarkers with immune reconstitution in HIV+ patients on ART

Background

HIV infection is characterized by CD4⁺ T-cells depletion related to gut damage, microbial translocation, immune activation and intestinal and systemic low-grade inflammation. With the use of antiretroviral treatment, these alterations in HIV+ patients reach similar levels to HIV- controls. However, almost 20% patients have deficient immune reconstitution of CD4⁺ T-cells, which make them more susceptible to develop non-AIDS and AIDS comorbidities.

Methods

HIV+ patients on ART, with sustained virologic control were grouped according to their immune reconstitution as: immunological responders (n = 18) and immunological non-responders (n = 18); also, HIV- controls were enrolled (n = 14). CD4⁺ and CD8⁺ T-cell activation (HLA-DR⁺ and CD38⁺ single and co-expression) were measured by flow cytometry. Serum levels of sCD14, sCD163, lipopolysaccharide, I-FABP, sST2, as well as fecal levels of calprotectin, lactoferrin and secretory IgA were evaluated by ELISA. Levels of C-reactive protein were determined by a high sensibility singleplex bead-based immunoassay. Serum and fecal concentrations of proinflammatory cytokines were quantified by multiplex bead-based immunoassay.

Results

HLA-DR⁺ and CD38⁺ co-expression, as well as median fluorescence intensity in CD4⁺ and CD8⁺ T-cells subpopulations was greater in immunological non-responders group, after normalization and fold change calculation. Similarly, this group presented higher levels of sCD14, C-reactive protein, as well as fecal calprotectin and lactoferrin. Furthermore, both HIV+ groups showed elevated levels of proinflammatory cytokines in stool.

Conclusions

Our data suggests that despite the virologic control, HIV+ patients under treatment with deficient immune reconstitution showed elevation of both innate and T-cells immune activation, as well as intestinal and systemic inflammation. However, some patients with CD4⁺ T-cells count above 350 cells/μL also presented these alterations. Future studies are necessary to evaluate the dynamics of multiple systemic and intestinal biomarkers in diverse types of HIV+ patients, as such as their clinical impact.

Mitigating Coronavirus Induced Dysfunctional Immunity for At-Risk Populations in COVID-19: Trained Immunity, BCG and "New Old Friends"

The novel, highly contagious coronavirus SARS-CoV-2 spreads rapidly throughout the world, leading to a deadly pandemic of a predominantly respiratory illness called COVID-19. Safe and effective anti-SARS-CoV-2 vaccines are urgently needed. However, emerging immunological observations show hallmarks of significant immunopathological characteristics and dysfunctional immune responses in patients with COVID-19. Combined with existing knowledge about immune responses to other closely related and highly pathogenic coronaviruses, this could forebode significant challenges for vaccine development, including the risk of vaccine failure. Animal data from earlier coronavirus vaccine efforts indicate that elderly people, most at risk from severe COVID-19 disease, could be especially at risk from immunopathologic responses to novel coronavirus vaccines. Bacterial "new old friends" such as Bacille Calmette-Guérin (BCG) or Mycobacterium obuense have the ability to elevate basal systemic levels of type 1 cytokines and immune cells, correlating with increased protection against diverse and unrelated infectious agents, called "trained immunity." Here we describe dysfunctional immune responses induced by coronaviruses, representing potentially difficult to overcome obstacles to safe, effective vaccine development for COVID-19, and outline how trained immunity could help protect high risk populations through immunomodulation with BCG and other "new old friends."

Persistent high levels of immune activation and their correlation with the HIV-1 proviral DNA and 2-LTR circles loads, in a cohort of Mexican individuals following long-term and fully suppressive treatment

OBJECTIVES

The aim of this study was to investigate the correlation between the HIV-1 reservoir and the levels of immune activation in chronic patients under fully suppressive cART.

METHODS

We quantified the HIV proviral DNA and 2-LTR circles loads from PBMCs, the levels of CD38+ and Ki-67+ T-cells, and the levels of IL-7 in a cohort of patients with more than 5 years of ART at enrollment and after 1 year.

RESULTS

In 29 participants with a median of 8 years (IQR, 6.9-9.4) under suppressive cART we found higher levels of CD8+ CD38+ T-cells after 1-year (P = .000). There was a non-statistically significant poor correlation between the levels of immune activation and the proviral DNA of CD4+ and CD8+ T-cells. Ki-67+ T-cells declined without significant differences, and there was no significant correlation with the proportion of CD38+. IL-7 decreased at the follow-up observation (P = .094), but there was no correlation with the levels of CD38+ and Ki-67+ T-cells.

CONCLUSIONS

We found a weak but non-statistically significant correlation of the levels of T-cell activation with the proviral DNA and 2-LTR circles. This suggests the likely occurrence of further mechanisms driving chronic versus early immune activation other than viral replication by itself in chronic patients.

CD8 T cells targeting adapted epitopes in chronic HIV infection promote dendritic cell maturation and CD4 T cell trans-infection

HIV-1 frequently escapes from CD8 T cell responses via HLA-I restricted adaptation, leading to the accumulation of adapted epitopes (AE). We previously demonstrated that AE compromise CD8 T cell responses during acute infection and are associated with poor clinical outcomes. Here, we examined the impact of AE on CD8 T cell responses and their biological relevance in chronic HIV infection (CHI). In contrast to acute infection, the majority of AE are immunogenic in CHI. Longitudinal analyses from acute to CHI showed an increased frequency and magnitude of AE-specific IFNγ responses compared to NAE-specific ones. These AE-specific CD8 T cells also were more cytotoxic to CD4 T cells. In addition, AE-specific CD8 T cells expressed lower levels of PD1 and CD57, as well as higher levels of CD28, suggesting a more activated and less exhausted phenotype. During CHI, viral sequencing identified AE-encoding strains as the dominant quasispecies. Despite increased CD4 T cell cytotoxicity, CD8 T cells responding to AE promoted dendritic cell (DC) maturation and CD4 T cell trans-infection perhaps explaining why AE are predominant in CHI. Taken together, our data suggests that the emergence of AE-specific CD8 T cell responses in CHI confers a selective advantage to the virus by promoting DC-mediated CD4 T cell trans-infection.

HIV-1 infection remains a critical public health threat across the world. Over the past two decades, CD8 T cells have been clearly shown to exert immune pressure on HIV and drive viral adaptation. Previously, our group reported that such HLA-I associated adaptations can predict clinical outcomes and are beneficial to HIV-1 as CD8 T cells are unable to recognize epitopes with adaptation in acute HIV infection. However, it is still unclear how HIV-1 adaptation impacts CD8 T cells during chronic HIV infection. In this study, we observed an enhancement of CD8 T cell responses targeting adapted epitopes in chronic infection. Although these responses were cytotoxic, they also exhibited a “helper” effect by promoting viral infection of CD4 T cells via interaction with dendritic cells. This phenomenon may contribute to the persistence of adapted viruses. In summary, these findings present a novel mechanism of CD8 T cell driven HIV-1 adaptation.

An altered cytotoxic program of CD8+ T-cells in HIV-infected patients despite HAART-induced viral suppression

Despite the suppression of viral replication induced by the highly active anti-retroviral therapy (HAART), an increased immune activation and inflammatory state persists in HIV-infected patients, contributing to lower treatment response and immune reconstitution, and development of non-AIDS conditions. The chronic activation and inflammation affect the functionality and differentiation of CD8+ T-cells, particularly reducing their cytotoxic capacity, which is critical in the control of HIV replication. Although previous studies have shown that HAART induce a partial immune reconstitution, its effect on CD8+ T-cells cytotoxic function, as well as its relationship with the inflammatory state, is yet to be defined. Here, we characterized the functional profile of polyclonal and HIV-specific CD8+ T cells, based on the expression of cell activation and differentiation markers, in individuals chronically infected with HIV, under HAART. Compared with seronegative controls, CD8+ T-cells from patients on HAART exhibited a low degranulation capacity (surface expression of CD107a), with consequent low secreted levels and high intracellular expression of granzyme B and perforin. This degranulation defect was particularly observed in those cells expressing the activation marker HLA-DR, which were further characterized as effector memory cells with high expression of CD57. The expression of CD107a, but not of granzyme B and perforin, in CD8+ T-cells from HIV-infected patients on HAART reached levels similar to those in seronegative controls when the treatment duration was higher than 25 months. In addition, the expression of CD107a was negatively correlated with the expression of exhaustion markers on CD8+ T-cells and the plasma inflammatory molecule sCD14. Thus, despite HAART-induced viral suppression, CD8+ T-cells from HIV-infected patients have an alteration in their cytotoxic program. This defect is associated with the cellular activation, differentiation and exhaustion state, as well as with the inflammation levels, and can be partially recovered with a long and continuous treatment.

Clinical characteristics of pediatric HIV-1 patients treated with first-line antiretroviral therapy in Vietnam: a nested case-control study

OBJECTIVES

Over the past decades, Vietnam has made great strides in reducing the rate of mortality in HIV-related deaths, due to increased access of antiretroviral therapy (ART); however, given the significantly high level of treatment failure (TF), it is essential to identify markers that describe the failure of ART in HIV-1 infected children.

METHODS

A nested case-control study was conducted with clinical data collected from 101 HIV-infected children [26 TF and 75 treatment success (TS)] at National Hospital of Pediatrics, Vietnam (2008-2012).

RESULTS

The results showed that certain factors including height, weight, vaccination with Hepatitis B, and platelet were significantly different between TF and TS before starting the treatment. In addition, age to start the treatment, CD4 percentage, and opportunistic infection were found to significantly predict treatment outcome most frequently, implying the importance of clinical markers in the treatment response by Cox regression analysis.

CONCLUSIONS

There is an inherent complexity within clinical markers that is challenging to determine HIV-pediatric failure and further research is needed to build a complete picture to guide clinical, evidence-based practice.

Effect of antiviral treatment of chronic hepatitis C on the frequency of regulatory T cells, T-cell activation, and serum levels of TGF-beta

The aim was to analyze T-regulatory cells (Tregs), activated CD8(+) T cells, and transforming growth factor-beta (TGF)-β in hepatitis C patients. We enrolled 31 patients with chronic genotype 1 hepatitis C virus (HCV) infection, 30 seropositive persons with spontaneous HCV elimination, and 23 healthy volunteers. The patients were examined at the beginning of the interferon-alpha (IFN-α)-based therapy (baseline) and at weeks 4 (W4) and 12 (W12) of the therapy. The percentage of Tregs and the expression of activation markers CD38 and HLA-DR on CD8(+) T cells were analyzed in the peripheral blood by flow cytometry. Serum levels of TGF-β were measured in a multiplex assay using flow cytometry. The percentage of Tregs in patients was higher than in controls and seropositive persons. Similarly, the percentage of CD8(+) T cells expressing CD38 and HLA-DR was higher in patients compared with controls and seropositive persons. Chronic HCV infection is associated with elevated circulating Tregs and activated CD8(+) T cells. During IFN-α-based therapy these cells gradually increase, whereas TGF-β serum levels decrease.

CD38+CD8+ and CD38+CD4+ T Cells and IFN Gamma (+874) Polymorphism Are Associated with a Poor Virological Outcome

The main objective of the work was to evaluate the use of CD38 on T lymphocytes, IFNγ (+874 A/T), and IL-10 (-1082 A/G) polymorphisms in HIV-infected patients under antiretroviral (ARV) therapy. Sixty-one patients were selected at the outpatient clinic for HIV infection at the Hospital São José de Doenças Infecciosas, Fortaleza, Ceará, Brazil. The patients were classified into two groups, according to viral load after one year of ARV therapy. In the aviremic group (group I), a reduction of 35.5% of CD38+CD4+ T cells was observed (p = 0.02) and 49.3% of CD38+CD8+ T cells (p = 0.001). In the viremic group (group II), a reduction of 37.2% of CD38+CD4+ T cells (p = 0.067), and 21.4% of CD38+CD8+ T cells (p = 0.60) occurred. No association was found between IL-10 (-1082) polymorphism and the type of response to ARV therapy. Regarding the gene polymorphism on IFNγ (+874 T/A), 73.34% of group I and 33.3% of group II presented the AA genotype. The relative risk of the individuals carrying AA genotype or the A allele and not being able to suppress the viral load level after one year of ARV therapy was 3.44 (1.25-9.45; p = 0.014) or 2.35 (1.05-5.26; p = 0.027), respectively. Our data suggested that an augmented frequency of activated CD38+CD8+ T cells as well as the presence of the A allele of IFNγ polymorphism could contribute to a reduced virological suppression in patients under antiretroviral therapy.

Long-term effect of highly active antiretroviral therapy on immunologic features in children

BACKGROUND

Highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus infection (HIV) into a chronic condition. The effects of long-term HAART on the immune system activity of early infected children are not fully understood. Hence, the aim of this review is to investigate immune system recovery and residual alteration in HIV-infected children receiving HAART in high-income countries.

METHODS

A systematic review was performed by searches of PubMed and references of the relevant articles. Studies published between January 1, 2000 and April 1, 2014 and conducted in high-income countries reporting data on immunological features in HIV-infected children receiving HAART were included in this review.

RESULTS

Fifty-three articles were included in this review. Present knowledge on B-cell and T-cell function, immunoglobulin production, response to vaccine and innate immune system activity in HIV-infected children receiving HAART is discussed.

CONCLUSION

Starting therapy as soon as diagnosis is ascertained and monitoring vaccine response in children under HAART are the most important tools to safeguard immunological function in HIV-infected children.

Age-related expansion of Tim-3 expressing T cells in vertically HIV-1 infected children

As perinatally HIV-1-infected children grow into adolescents and young adults, they are increasingly burdened with the long-term consequences of chronic HIV-1 infection, with long-term morbidity due to inadequate immunity. In progressive HIV-1 infection in horizontally infected adults, inflammation, T cell activation, and perturbed T cell differentiation lead to an "immune exhaustion", with decline in T cell effector functions. T effector cells develop an increased expression of CD57 and loss of CD28, with an increase in co-inhibitory receptors such as PD-1 and Tim-3. Very little is known about HIV-1 induced T cell dysfunction in vertical infection. In two perinatally antiretroviral drug treated HIV-1-infected groups with median ages of 11.2 yr and 18.5 yr, matched for viral load, we found no difference in the proportion of senescent CD28(-)CD57(+)CD8(+) T cells between the groups. However, the frequency of Tim-3(+)CD8(+) and Tim-3(+)CD4(+) exhausted T cells, but not PD-1(+) T cells, was significantly increased in the adolescents with longer duration of infection compared to the children with shorter duration of HIV-1 infection. PD-1(+)CD8(+) T cells were directly associated with T cell immune activation in children. The frequency of Tim-3(+)CD8(+) T cells positively correlated with HIV-1 plasma viral load in the adolescents but not in the children. These data suggest that Tim-3 upregulation was driven by both HIV-1 viral replication and increased age, whereas PD-1 expression is associated with immune activation. These findings also suggest that the Tim-3 immune exhaustion phenotype rather than PD-1 or senescent cells plays an important role in age-related T cell dysfunction in perinatal HIV-1 infection. Targeting Tim-3 may serve as a novel therapeutic approach to improve immune control of virus replication and mitigate age related T cell exhaustion.

Acute cytomegalovirus infection is associated with increased frequencies of activated and apoptosis-vulnerable T cells in HIV-1-infected infants

Cytomegalovirus (CMV) coinfection is associated with infant HIV-1 disease progression and mortality. In a cohort of Kenyan HIV-infected infants, the frequencies of activated (CD38(+) HLA-DR(+)) and apoptosis-vulnerable (CD95(+) Bcl-2(-)) CD4(+) and CD8(+) T cells increased substantially during acute CMV infection. The frequency of activated CD4(+) T cells was strongly associated with both concurrent CMV coinfection (P = 0.001) and HIV-1 viral load (P = 0.05). The frequency of apoptosis-vulnerable cells was also associated with CMV coinfection in the CD4 (P = 0.02) and CD8 (P < 0.001) T cell subsets. Similar observations were made in HIV-exposed uninfected infants. CMV-induced increases in T cell activation and apoptosis may contribute to the rapid disease progression in coinfected infants.

Expression of interleukin-15 and interleukin-15Rα in monocytes of HIV type 1-infected patients with different courses of disease progression

Interleukin-15 (IL-15) enhances the effector mechanisms of anti-HIV immune responses and thus is considered a potential adjuvant of HIV-1 vaccine. However, there are a lack of data concerning the relationships between IL-15 expression and regulation in HIV-1-infected patients and the course of disease progression. We found that IL-15, but not IL-15Rα, is expressed at significantly higher levels in the CD14(+) monocytes [stimulated or not with interferon (IFN)-γ] of long-term nonprogressors (LTNP) than in those of HIV-1 progressors or healthy controls. There was no between-group difference in the amounts of soluble IL-15 released from the cells. We also found that like the healthy controls, the LTNP expressed the IL-15 and IL-15Rα genes in a more coordinated manner than the progressors. Our findings show that there are significant differences in IL-15 expression between patients with different courses of HIV infection, and that the coordinated expression of the IL-15 and IL-15Rα genes is dysregulated in patients with progressive disease. They also provide important information concerning the mechanisms of infection and the potential use of IL-15 as a therapeutic agent.

Further evidence that the expression of CD38 and HLA-DR(+) in CD8(+) lymphocytes does not correlate to disease progression in HIV-1 vertically infected children

BACKGROUND

In adults, an increase in CD8(+)CD38(+) T cell levels is a strong indicator of disease progression in HIV infection. However, in children, data are conflicting. Slow-progressing children (SPC) provide an exceptional resource for the investigation and clarification of the immunological and virological mechanisms of natural control of HIV infection and can be used to investigate prognostic indicators of disease progression.

OBJECTIVES

To investigate the immune activation status and T regulatory (Treg) cell levels in SPC.

STUDY DESIGN

A cross-sectional study was carried out on 28 children 8 years old and older who were vertically infected with HIV. The children were stratified into 3 groups according to their clinical outcome: SPC (anti-retroviral-therapy-naïve; ≥8 years-old; CD4 ≥20%; viral load <25,000 copies), IF/VF (anti-retroviral-therapy but with no therapeutic response), and IS/VS (anti-retroviral therapy with good therapeutic response). Uninfected children (NI) were assessed as healthy control group.

RESULTS

A higher percentage of activated CD8(+) T cells were found in all HIV infected children, regardless of the evolution of disease. The activation of CD8(+) T cells was not associated with either viral load or the percentage of CD4(+) T cells. In addition, Treg cell levels did not show any correlation with the clinical outcome or the activation status of CD8(+) T cells.

CONCLUSIONS

HIV-1-infected children presented an increased percentage of activated CD8(+) T cells and an unaltered percentage of Treg cells, regardless of their clinical evolution. Thus, these immunological parameters should not be used for prognostic evaluation.

Identification of three immunologic correlates for HIV type 1 pathogenesis in youth

To evaluate the stability and heterogeneity of cytokine and chemokine profiles in 80 youth with and without HIV-1 infection, we tested plasma samples at repeated visits without antiretroviral therapy. Among nine analytes that were quantified using multiplexing assays, interleukin 10 (IL-10), IL-18, and soluble CD30 persistently showed a positive correlation with HIV-1 viral load (Spearman ρ = 0.40-0.59, p < 0.01 for all). A negative correlation with CD4(+) T cell counts (ρ = -0.40 to -0.60, p < 0.01 for all) was also persistent for the three analytes. Analyses restricted to 48 AIDS-free youth (96 visits) yielded similar findings, as did multivariable models in which race, sex, age, body mass index, and time interval between visits were treated as covariates. These relationships reflected two novel features observed for all three analytes. First, their presence in plasma was relatively stable between visits (ρ = 0.50-0.90, p < 0.03), regardless of HIV-1 infection status. Second, pairwise correlation was strong and persistent in HIV-1-seropositive youth (ρ = 0.40-0.59, p < 0.01), but not in HIV-1, seronegatives (p > 0.13). Additional analytes, especially eotaxin/CCL11 and SDF-1β/CXCL12, had no correlation with HIV-1-related outcomes despite their stability between visits. Overall, circulating IL-10, IL-18, and soluble CD30 could partially track unfavorable responses to HIV-1 infection in youth. These markers of persistent immune activation are individually and collectively indicative of HIV-1 pathogenesis.

Impact of changes in antigen level on CD38/PD-1 co-expression on HIV-specific CD8 T cells in chronic, untreated HIV-1 infection

Excessive immune activation is a hallmark of chronic uncontrolled HIV infection. During the past years, growing evidence suggests that immune inhibitory signals also play an important role in progressive disease. However, the relationship between positive and negative immune signals on HIV-specific CD8 T cells has not been studied in detail so far in chronic HIV-1 infection. In this study, the expression of markers of positive (CD38) and negative (PD-1) immune signals on virus-specific CD8 T cells in chronic, untreated HIV-1 infection was evaluated using intracellular cytokine staining. Viral escape mutations were assessed by autologous virus sequence analysis and subsequent peptide titration assays. Single-epitope CD8 T-cell responses toward Gag, Pol, and Nef were compared in 12 HIV-1 controllers (viral load <5,000 cp/ml) and 12 HIV-1 progressors (viral load >50,000 cp/ml) and a highly significant increase of CD38/PD-1 co-expression on virus-specific CD8 T cells in progressors was found (P < 0.0001). The level of CD38/PD-1 co-expression was independent of epitope specificity. Longitudinal follow-up revealed a clear drop in CD38/PD-1 co-expression on virus-specific CD8 T cells after the suppression of antigen following either viral escape mutation or the initiation of HAART (P = 0.004). Antigen persistence with a fluctuating viral load revealed stable levels of CD38/PD-1 co-expression whereas significant rises in viral load were accompanied or even preceded by substantial increases in CD38/PD-1 co-expression. The CD38/PD-1 phenotype clearly distinguishes HIV-specific CD8 T-cell responses between controllers and progressors. Whether it plays a causative role in disease progression remains debatable. J. Med. Virol. 82:358-370, 2010. (c) 2010 Wiley-Liss, Inc.

Relevance of CD38 expression on CD8 T cells to evaluate antiretroviral therapy response in HIV-1-infected youths

Surrogate markers for monitoring immuno-virological discordant responders, in addition to plasma viral load and CD4 cells, are still lacking. We assessed the diagnostic utility of CD38 expression on CD8 T cell assay, alone or in association with lymphocyte proliferation to mycotic antigens, in evaluating antiretroviral response. 28 vertically HIV-infected youths, 21 HAART- and seven 2 nucleotide reverse transcriptase inhibitors-treated, were enrolled in a retrospective study. Responders (57.1%) and non-responders (42.9%) to stable antiretroviral therapy for a minimum of 6 months, on the basis of viral load and CD4 T cells, comprehensively evaluated by CD38 expression on CD8 T lymphocytes [measured as CD38 antibody bound per CD8 T cell (CD38 ABC) and %CD38+ of total CD8 T cells (%CD38/CD8)] and lymphocyte proliferation to P. jiroveci, C. albicans, C. neoformans, A. fumigatus at a single time point after treatment, were selected. CD38 expression > or =2401 CD38 ABC and > or =85% CD38/CD8 cut-off points, accurately discriminates responders versus non-responders, both measures resulting in 75.0% (CI 42.8-94.5) sensitivity (identification of non-responder) and 93.8% (CI 69.8-99.8) specificity (identification of responder), when considered as single assays. The association '> or =2401 CD38 ABC or > or =85% CD38/CD8' improved sensitivity to 83.3% (CI 51.6-97.9), while the association '<2401 CD38ABC (or <85% CD38/CD8) and lymphoproliferative response positive to > or =2 tested organisms' improved specificity to 100% (CI 79.4-100). In conclusions, CD38 expression and mycotic antigen-specific T-cell proliferation may be used as additional parameters to existing criteria to evaluate antiretroviral response in immuno-virological discordant patients.

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.

Close association of CD8+/CD38 bright with HIV-1 replication and complex relationship with CD4+ T-cell count

BACKGROUND

Measuring lymphocyte activation provides information in addition to CD4(+) T-cell count for immune monitoring of HIV-1 infected patients. CD38 is a well-established activation marker that is generally analyzed on the whole population of CD8(+) T-cells. Focusing specifically on CD38 high expression (CD8(+)/CD38(bright)) may be an interesting surrogate gating strategy because CD38(bright) characterizes principally activated memory cells.

METHODS

CD8(+)/CD38(bright) was investigated in 1,353 HIV-1 infected patients over a one-year period to establish relevant cutoff values and clarify the relationships of this marker with HIV-1 RNA viral load (VL) and CD4(+) T-cell count.

RESULTS

The CD8(+)/CD38(bright) (>8,500 CD38 binding site per cells) is well correlated with HIV-1 VL (r = 0.87, P < 0.001) in this longitudinal follow-up of nonimmunodepressed patients that initiated antiviral therapy (ART). In aviremic patients on ART, the marker was highly predictive of VL rebound (sensitivity 93%, specificity 64% for a VL level of detection >200 copies/ml). While the CD8(+)/CD38(bright) moderately correlated with CD4(+) T-cell count independently of the VL (r = -0.37, P < 0.001), it increased dramatically in aviremic patient groups that exhibited profound CD4(+) T-cell depletion (median 39% for CD4(+) T-cell counts <50/mm(3)). This result indicates that other additional immunological and/or viral factors than readily detectable HIV-1 replication appears to be involved in T-cell activation of immunodepressed individuals.

CONCLUSIONS

CD8(+)/CD38(bright) is an effective marker for monitoring T-cell activation, which is a central factor of HIV-1 pathogenesis. This gating strategy requires only a single additional staining in conventional four color CD4 protocols.

Immunological recovery and metabolic disorders in severe immunodeficiency HIV type 1-infected children on highly active antiretroviral therapy

Little is known about immunologic reconstitution in children on highly active antiretroviral treatment (HAART) during very long-term periods. A retrospective study was carried out to assess the effectiveness and development of metabolic disorders after very long-term periods on HAART in HIV-infected children with severe immunodeficiency. We included 55 children who were stratified into three groups according to %CD4(+) pre-HAART and rate of immunologic recovery: (1) S1-Rec: CD4(+) < or =5% at baseline and slow immunologic recovery; (2) S2-Rec: CD4(+) 5-15% at baseline and slow immunologic recovery; (3) R-Rec: CD4(+) < or =15% at baseline and rapid immunologic recovery (reference group). An adequate immune recovery after 8 years on HAART was achieved by only 25% of children. S1-Rec never achieved a mean of CD4(+) > or =25% after 8 years on HAART. All children had a significant increase in plasma cholesterol levels during the first 2 years. Afterward, cholesterol levels reached a plateau and remained stable until year 8 of follow-up. Higher rates of lipodystrophy were found in the R-Rec group [14 (100%)] than in the S1-Rec group [9/19 (47.4%)] or the S2-Rec group [13/20 (65%)] at the end of the study (p = 0.006). Overall, having a low nadir of CD4(+) hindered immune reconstitution; however, children with rapid immunologic recovery showed a higher prevalence of the lipodystrophy syndrome.

Early changes in T-cell activation predict antiretroviral success in salvage therapy of HIV infection

OBJECTIVE

Because effective antiretroviral therapy (ART) reduces immune activation, we hypothesize that early changes in immune activation are associated with subsequent virologic response to therapy.

DESIGN

Observational cohort study.

SETTING

Institutional HIV clinic.

SUBJECTS

Thirty-four adult HIV patients with virologic failure on their current antiretroviral regimen.

INTERVENTION

Change to salvage regimen selected by patient's physician.

MAIN OUTCOME MEASURES

Measures of immune activation at baseline and at 2, 4, 8, and 24 weeks after enrollment. Data were analyzed by proportional hazards (PH) models.

RESULTS

PH models showed that reductions between baseline and week 2 in expression of CD38 (P = 0.02) or CD95 (P = 0.02) on CD4 T cells were associated with increased likelihood of achieving virologic suppression. Kaplan-Meier analysis demonstrated that patients who had reductions within the first 2 weeks of therapy in CD4 T-cell expression of CD38 (P = 0.003) or CD95 (P = 0.08) were more likely to achieve viral suppression than those who did not.

CONCLUSIONS

Reduced CD4 T-cell expression of CD38 and CD95 occurring within 2 weeks of salvage therapy is associated with subsequent viral suppression. Monitoring CD38 and CD95 may allow earlier assessment of the response to ART.

Treatment of pediatric HIV infection

HIV-infected children require a peculiar management when compared to infected adults. Antiretroviral therapy has been quite well adapted to children, but new studies are needed to answer many unsolved questions, such as when to start therapy in asymptomatic infected children. Recently, several guidelines have been updated. In this review, we compare these recommendations together with the latest studies concerning the treatment of HIV in children. A triple-drug combination therapy based either on nonnucleoside reverse transcriptase inhibitors or protease inhibitors is the recommended initial therapy. After treatment failure, a second-line therapy should be based on switching between these two regimens. Antiretroviral therapy should be managed by an expert in pediatric and adolescent HIV infection. The importance of children's adherence to therapy is a crucial point, particularly in adolescents.

[Viral load in HIV-infected children on high activity antiretroviral therapy]

BACKGROUND AND OBJECTIVE

To determine whether viral load (VL) prior to undetectable VL has predictive value on the re-emergence of VL (> 400 copies/ml, > 5,000 copies/ml and > 30,000 copies/ml).

PATIENTS AND METHOD

Retrospective study carried out on 81 vertically human immunodeficiency virus (HIV)-infected children on antiretroviral therapy who were distributed in 3 groups according to their median value of VL one year before reaching undetectable VL: A-group: VL < 5,000 copies/ml; B-group: VL between 5,000 and 30,000 copies/ml, and C-group: VL > 30,000 copies/ml.

RESULTS

During the whole follow-up period, 63 (77.8%) children had a rebound of VL > 400 copies/ml. Forty-two (51.8%) children had a rebound of VL > 5,000 copies/ml. Twenty-seven (33.3%) children had a rebound of VL > 30,000 copies/ml. HIV-children of B-group had values of hazard ratio (HR) statistically significant for a rebound of VL > 5,000 copies/ml. Moreover, HIV-children of C-group had values of HR greater and statistically significant for a rebound of VL > 500, > 5,000 and > 30,000 copies/ml. For a rebound of VL > 30,000 copies/ml, the C-group had values of RR > 12.

CONCLUSIONS

High VL levels prior to undetectable VL can be a useful prognostic marker of virological failure in HIV-infected children.

CD4(+) T-cell immunodeficiency is more dependent on immune activation than viral load in HIV-infected children on highly active antiretroviral therapy

OBJECTIVE

The aim of this study was to analyze the association between CD4(+) depletion and immune activation in HIV-1-infected children on highly active antiretroviral therapy (HAART).

DESIGN AND SETTING

We carried out a cross-sectional study to determine the profile of several immunologic parameters in 143 children on HAART for more than 24 weeks. Children were stratified according to current immunologic status (CD4 < or =15%, 15%-25%, and > or =25%) and viral load (VL) levels (<400 copies/mL; 400-10,000 copies/mL; and >10,000 copies/mL). We also studied 23 uninfected children as healthy controls.

METHODS

Viral load (HIV-RNA copies per milliliter) was quantified using reverse transcriptase polymerase chain reaction molecular assay. T-cell subsets were determined by multiparametric flow cytometry.

RESULTS

HIV-infected children with low percentage of CD4(+) had high memory (CD45RO(+)) and low naive (CD45RA(+)) CD4(+) and CD8(+) T-cell values. Furthermore, children with CD4(+) >25% had similar memory and naive CD4(+) values as the healthy control group, whereas memory and naive CD8(+) subsets were different from the healthy control values. In these HIV-infected children, when CD4(+) was depleted, the amount of naive plus central memory CD8(+) (CD28(+)CD57(-)) cells was decreased, whereas effector CD8(+) (CD28(-)CD57(+)) cells were upregulated, and these values were always higher than healthy control values. Furthermore, children with low percentage of CD4(+) showed significant upregulation of HLA-DR(+)CD38(+) and HLA-DR(+) in both CD4(+) and CD8(+) T-cells independent of VL levels.

CONCLUSIONS

Our data suggest that elevated immune activation could be responsible for CD4(+) depletion rather than HIV replication because immunologic status is associated directly to immune activation and not to VL levels in HIV-infected children on HAART.

Evaluation of HIV-1 p24 Antigenemia and Level of CD8+CD38+ T cells as Surrogate Markers of HIV-1 RNA Viral Load in HIV-1-Infected Patients in Dakar, Senegal

Alternative, affordable, and simple assays to monitor antiretroviral therapy (ART) in resource-poor settings are needed. We have evaluated and compared a heat-denatured (HD) HIV p24 amplified enzyme-linked immunosorbent assay from Perkin-Elmer and CD38CD8 T-cell levels, determined by flow cytometry, for their capacity to predict viral load (VL) in HIV-1-infected patients from Senegal. Median fluorescence intensity (MFI) of CD38 expression on memory (CD45RO) CD8 T cells correlated better with RNA VL than HD p24 antigenemia (R = 0.576, P < 0.0001 vs R = 0.548, P < 0.0001). MFI of CD38 expression on memory CD8 T cells could predict detectable RNA VL (VL = 2.6 log10) with a sensitivity of 87% and a specificity of 74%. A comparable sensitivity (89%) could be reached for HD p24 assay, but only to predict RNA VL of more than 5 logs, which might lead to unacceptable delays in clinical decision making. The clinical use of the HD p24 assay to monitor ART in Senegal would require more comparative data about the kinetics of p24 antigen and HIV RNA in peripheral blood as well as further evaluation regarding its sensitivity toward subtype A and CRF02. MFI of CD38 expression on memory CD8 T cells appeared to be a better alternative to monitor ART in HIV-infected patients from Senegal.

Long-Term Effects of Highly Active Antiretroviral Therapy in Pretreated, Vertically HIV Type 1-Infected Children: 6 Years of Follow-Up

BACKGROUND

Several studies of children with human immunodeficiency virus (HIV) type 1 infection have demonstrated sustained increases in CD4+ cell count, even when virological failure has occurred after receipt of highly active antiretroviral therapy (HAART), but these studies were of limited duration. Moreover, the CD4+ cell count threshold at which antiretroviral treatment should be initiated is still unsettled. The aim of this study was to define the long-term impact of HAART on CD4+ cell percentage and viral load according to CD4+ cell percentages before HAART was initiated.

METHODS

We conducted a retrospective study of 113 pretreated HIV-1-infected children stratified by pre-HAART CD4+ cell percentage (<5%, 5%-15%, 15%-25%, and >25%). The inclusion criteria were as follows: initiating HAART with a protease inhibitor, having 6 years of follow-up after starting HAART, having a CD4+ cell count or viral load recorded before initiation of HAART, and having received mono- or dual-nucleoside therapy before starting HAART.

RESULTS

During the first 2 years of HAART, HIV-1-infected children experienced a significant increase in CD4+ cell percentage and a decrease in viral load (P<.05). During their last 4 years of receiving HAART, we found a significant decrease in viral load but not an increase in CD4+ cell percentage, because the CD4+ cell percentage reached a plateau after the second year of HAART. Moreover, children with CD4+ cell percentages of <5% at baseline did not achieve CD4+ cell percentages of >25% after 6 years of HAART. Children with CD4+ cell percentages of 5%-25% at baseline had a strong negative association with achieving CD4+ cell percentages of >30% for at least 6 and 12 months but not with achieving CD4+ cell percentages of >30% for at least 24 months.

CONCLUSIONS

Long-term HAART allowed for restoration of CD4+ cell counts and control of viral loads in HIV-1-infected children. However, initiating HAART after severe immunosuppression has occurred is detrimental for the restoration of the CD4+ cell count.

Immune reconstitution and predictors of virologic failure in adolescents infected through risk behaviors and initiating HAART: week 60 results from the PACTG 381 cohort

The responses to HAART in HIV-infected adolescents infected through risk behaviors are not well defined. PACTG 381 collected intensive immunologic and virologic data on youth naive to or with minimal exposure to antiretroviral therapy who began HAART. Subjects were evaluated according to their weeks 16-24 virologic response. Comparisons with a cohort of HIV-uninfected adolescents from the REACH cohort were performed. Cox proportional hazards models were used to identify baseline and week 24 predictors of virologic failure. Only 69 of 120 subjects (58%) achieved virologic suppression by weeks 16-24, whereas 55 of 69 (80%) demonstrated control to week 60. Higher CD4+ naive T cells (CD4+/62L+/RA+: hazard ratio [HR], 2.13; p = 0.018), higher CD8+ activated T cells (CD8+/CD38+/DR+: HR, 1.40, p = 0.028 per 100 cells/mm3) and higher CD8+ naive T cells (CD8+/62L+/RA+: HR, 1.72; p = 0.005) at weeks 16-24 in subjects with early viral success were predictive of subsequent failure. By week 60, total CD4+ T cells remained significantly lower than in uninfected controls. Adolescents beginning HAART achieve moderate rates of viral suppression by weeks 16-24. In those who do achieve early virologic control, suppression to week 60 is high although total CD4+ T cells remain significantly lower than in uninfected controls. Several T cell markers were predictive of subsequent virologic failure in subjects achieving short-term success. Further study is warranted to determine whether these predictors provide any benefit to clinical management.

Correlation of T-lymphocyte subpopulations with immunological markers in HIV-1-infected Indian patients

Progressive HIV disease is characterized by CD4 T cell decline and activation of the immune system. We aimed to study the quantitative alterations in the naive (CD45RA+CD62L+), memory/effector (CD45RO+) and activated (HLA-DR+CD38+) T-lymphocyte subpopulations in antiretroviral treatment naive, HIV-1 infected Indian patients by three-color multi-parametric flow cytometry. The association of different CD4+ and CD8+ T cell subsets with the immunological markers- CD4+ and CD8+ T cell percentages was examined by calculating the partial correlation coefficients. We also observed significant differences in the expression of different CD4+ and CD8+ T-cell subsets among the two groups of patients formed using the median CD4+ T cell percentage value (15%) of the study population. The correlations of different CD4+ and CD8+ T cell subsets reflected the quantitative alterations in the T-lymphocyte subpopulations and activation of the immune system during HIV-infection. The study outcome also emphasizes the significance of the CD38+CD8+ T-lymphocyte subset as a prognostic marker for HIV management and ART monitoring in resource-limited settings of developing countries like India.

Studies on the potential use of CD38 expression as a marker for the efficacy of anti-retroviral therapy in HIV-1-infected patients in Thailand

The monitoring of the efficacy of anti-retroviral therapy (ART) is becoming an important issue in the developing world. The current use of CD4 counts, plasma viral loads, and monitoring of drug-resistant viruses are at present either uninformative or costly. Thus, more new cost-effective and practical techniques need to be established and implemented. Towards this goal, our lab has carried out studies on the potential use of CD38 frequency and density expression by flow analysis as a means to assess the efficacy of ART. Results of our studies using whole blood sample from normal healthy donors indicate that CD38 is expressed by a high frequency of not only CD4+ and CD8+ T cells but also most hematopoietic cell lineages analyzed. Detailed studies of CD38 expression along with other cell surface markers using whole blood sample from HIV-1-infected patients showed that the most discriminating change was the increased frequency and density of CD38 expression by CD3+CD8+ T cells. Of importance was our preliminary finding that a reversal of the increased frequency and density of CD38 expression by CD8+ T cells only appeared in the whole blood sample from patients who were responders to ART but not those who were drug failures. These initial data provide a platform and incentive for larger cohort studies including prospective pre- and post-ART for the institution of such monitoring techniques in resource limited settings.

Immunological changes after highly active antiretroviral therapy with lopinavir-ritonavir in heavily pretreated HIV-infected children

We evaluated the effect of salvage antiretroviral therapy with lopinavir/ritonavir (LPV/r) on the immune system of heavily antiretroviral pretreated HIV-infected children. We carried out a longitudinal study in 20 antiretroviral experienced HIV-infected children to determine the changes in several immunological parameters (T cell subsets, thymic function) every 3 months during 18 months of follow-up on salvage therapy with LPV/r. Statistical analyses were performed with the Wilcoxon test, taking as a reference the basal value at the entry in the study. HIV-infected children showed an increase of CD4+ T cells, a decrease in CD8+ T cells, and an increase in T cell rearrangement excision circle (TRECs) levels. The percentage of HIV children with undetectable viral load (VL < or = 400 copies/ml) increased significantly (p = 0.007) and the percentage with SI viral phenotype decreased significantly (p = 0.002) at the end of the study. Thus, the viral phenotype changed to NSI/R5 after salvage therapy with LPV/r. Interestingly, we observed a significant decrease of memory (CD4+ CD45RO+) and a moderate decrease of activated (CD4+ HLA-DR+, CD4+ HLA-DR+CD38, CD4+, CD45RO+HLA-DR+) CD4+ T cells during the follow-up. On the other hand, memory (CD8+ CD45RO+ and CD8+ CD45RO+CD38+), activated (CD8+ HLA-DR+CD38+, CD8+ HLA-DR+, CD8+ CD38+), and effector (CD8+ CD57+, CD8+ CD28(-)CD57+) CD8+ T cells had a very significant decrease during follow-up. Our data indicate an immune system reconstitution in heavily pretreated HIV-infected children in response to salvage therapy with LPV/r as a consequence of a decrease in immune system activation and an increase in thymic function.

Assessment of CD8 T cell immune activation markers to monitor response to antiretroviral therapy among HIV-1 infected patients in Côte d'Ivoire

Because of the paucity of plasma HIV RNA viral load (VL) tests in resource-poor settings, the CD4(+) T cell count is often used as the sole laboratory marker to evaluate the effectiveness of antiretroviral therapy (ART) in HIV-infected patients. In untreated patients, the level of activated T cells is positively correlated with VL and represents a prognostic marker of HIV infection. However, little is known about its value to predict early drug failure, taking into account the relatively high non-specific immune activation background observed in many resource-limited tropical countries. We assessed the use of immune activation markers (expression of CD38 and/or human leucocyte antigen-DR on CD8(+) lymphocytes) to predict virological response to ART in a cohort of HIV-1 infected patients in Abidjan, Côte d'Ivoire. Correlations between VL, absolute CD4(+) T cell counts and immune activation levels were examined in 111 HIV patient samples at baseline and after 6 and 12 months of therapy. The percentage of CD38(+) CD8(+) T cells appeared to be the best correlate of VL. In contrast, changes in CD4(+) T cell counts provided a poor correlate of virological response to ART. Unfortunately, CD38(+) CD8(+) percentages lacked specificity for the determination of early virological drug failure and did not appear to be reliable surrogates of RNA viral load. CD38(+) CD8(+) T cell percentages may, rather, provide a sensitive estimate of the overall immune recovery, and be a useful extra laboratory parameter to CD4 counts that would contribute to improve the clinical management of HIV-infected people when VL testing facilities are lacking.

Positive virological outcome after lopinavir/ritonavir salvage therapy in protease inhibitor-experienced HIV-1-infected children: a prospective cohort study

BACKGROUND

Lopinavir/ritonavir has demonstrated antiviral activity in the HIV-infected patient.

OBJECTIVE

To analyse virological response to lopinavir/ritonavir therapy in previously protease inhibitor (PI)-experienced HIV-1-infected children.

MATERIALS AND METHODS

Sixty-seven HIV-1-children on lopinavir/ritonavir were studied in a multicentre prospective cohort observational study. The outcome variables were undetectable viral load (uVL; VL < or =400 copies/mL) and virological failure after uVL with a rebound of VL >400 copies/mL. VL and genotype of HIV-1-isolates were measured using standard assays.

RESULTS

83.5% of children had a 1 log10 VL decrease including 65.6% who reached uVL. Children with >2 changes of antiretroviral therapy (ART) or >5 drugs needed a median time of 3-4 months higher than children with < or =2 changes of ART or < or =5 drugs previous to lopinavir/ritonavir, to reach those values, and the relative proportions (RP) were 2.2 (P =0.038) and 1.9 (P=0.050), respectively. Children with CD4+>15% (P=0.122), VL < or =30,000 (P < 0.001) copies/mL, and age >12 years (P=0.096) achieved an earlier control of VL during the follow-up. The children with virological failure or rebound of VL had higher baseline VL and lower CD4+ T-lymphocytes/mm3 and had taken a greater number of drugs previous to lopinavir/ritonavir. HIV-children with a new nucleoside reverse transcriptase inhibitor (NRTI), or protease inhibitor (PI) or PI plus non-nucleoside reverse transcriptase inhibitors (NNRTI) in the current regimen had a better virological response than children without these new drugs. Also, children with <6 protease mutations had an RP of 2.31 of achieving uVL.

CONCLUSIONS

Highly active antiretroviral therapy (HAART) including lopinavir/ritonavir induces beneficial effects in terms of virological outcome responses, and it is an effective option for salvage therapy in PI-experienced HIV-1-infected children.

[Changes in CD4+ and CD8+ T-cell subsets in HIV-infected children differently correlate with viral replication and thymic function]

BACKGROUND AND OBJECTIVE

We intended to study the relationship between T-cell subsets with plasmatic detectable viral load (VL) and T-receptor excision circles (TREC).

PATIENTS AND METHOD

Twenty HIV-infected children on highly active antiretroviral therapy (HAART) were recruited in a 1-year longitudinal retrospective study. We analyzed the relationship between changes in peripheral blood T-cell subsets, VL and TREC markers by lineal regression.

RESULTS

Memory and activated CD4+ T-cells increases had a negative association with log10 TRECs increases. However, naive CD4+ T-cells increases had a positive association with log10 TRECs increases. In contrast, memory, activated and effector CD8+ T-cells increases positively correlated with log10 VL increases. On the other hand, naive CD8+ T-cells increases had a negative association with log10 VL increases.

CONCLUSIONS

CD4+ and CD8+ T-cells subsets change in a different way as a response to the changes produced by HAART in HIV vertically infected children. CD4+ T-cells are more dependent on thymic function and CD8+ T-cells are more dependent on viral replication. Thus, the decline in cellular activation would allow the production of more naive T-cells by the thymus.

Impact of highly active antiretroviral therapy on CD4+ T cells and viral load of children with AIDS: a population-based study

In this study, we sought to characterize the changes over time at the population level on CD4(+) T cells and plasma viral load (VL) levels of HIV-1-infected children with or without AIDS. We carried out a retrospective study in 114 HIV-infected children during the calendar period that a highly active antiretroviral therapy (HAART) protocol was used. The HAART protocol consisted of three drugs: nucleoside analogue HIV-1 reverse transcriptase inhibitors, and/or HIV protease inhibitors, and/or nonnucleoside analogue HIV-1 reverse transcriptase inhibitors. The mean of CD4(+) T cells percentage and log(10) VL per calendar year were stratified by AIDS diagnostic. As new HAART strategies become available, an increase of CD4(+) T cells and a decrease of VL were observed over time, in children with and without AIDS. In 2001, children with AIDS reached values of CD4(+) T cells and VL similar to children without AIDS. In conclusion, our study shows that the generalized use of HAART has permitted improvement in immunological and virological status of HIV-infected children without AIDS, and more importantly in children with AIDS.