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

Efficacy of Bortezomib for Treating Anti-Interferon-Gamma Autoantibody-Associated Adult-Onset Immunodeficiency Syndrome

BACKGROUND

Currently, there is no effective treatment for adult-onset immunodeficiency (AOID) syndrome with anti-interferon-gamma autoantibodies (anti-IFN-γ-auto-Abs). This study aimed to investigate the effectiveness of bortezomib (BTZ) for decreasing anti-IFN-γ-auto-Abs.

METHODS

A pre- and post-intervention study was conducted from February 2017 through June 2019 at Siriraj Hospital (Bangkok, Thailand). Five patients were invited to receive once-weekly BTZ (1.3 mg/m2 body surface area) subcutaneously for 8 weeks followed by oral cyclophosphamide (1 mg/kg/d) for 4 months. The primary outcomes were the difference in antibody level at 8 and 48 weeks compared with baseline and the incidence of serious adverse events (AEs). The secondary outcome was the occurrence of opportunistic infections (OIs) during the 72 weeks after starting BTZ.

RESULTS

The median patient age was 46 years (range, 34-53). All patients had 3-5 OIs prior to enrollment. All patients were receiving antimycobacterial agents for treatment of nontuberculous mycobacterial infection at enrollment. There was no significant difference in the mean optical density of auto-Abs at 8 weeks (3.73 ± 0.72) or 48 weeks (3.74 ± 0.53) compared with baseline (3.84 ± 0.49; P = .336 and P = .555, respectively). However, after serum dilution, the antibody titer nonsignificantly decreased 8-16 weeks after BTZ initiation (P = .345). Ten OIs were observed 24-72 weeks after BTZ initiation.

CONCLUSIONS

Treatment with BTZ followed by cyclophosphamide yielded no significant decrease in antibody titer levels, and 10 OIs were observed during 24-72 weeks of BTZ treatment. No serious AEs were observed. Combining rituximab with BTZ is likely necessary to prevent generation of new autoantibody-producing plasma cells. Clinical Trials Registration. NCT03103555.

Circulating activated immune cells as a potential blood biomarkers of non-small cell lung cancer occurrence and progression

BACKGROUND

Treatment for non-small cell lung cancer (NSCLC) has greatly improved in recent years. However, noninvasive early screening for carcinogenesis and progression unclear. The aim of this study was to explore the predictive value of peripheral blood immune cells in untreated NSCLC patients.

METHODS

We retrospectively enrolled 305 untreated NSCLC patients and 132 healthy participants from February 2016 to August 2019 in Peking Union Medical College Hospital. Immune cell levels were determined by flow cytometry and routine blood tests.

RESULTS

NSCLC patients had lower levels of T lymphocytes, NK cells, CD8+ T cells, naïve CD4+/CD4+, naïve CD4+ T cells and higher levels of CD4+ T cells, memory CD4+/CD4+ T cells, memory CD4+ T cells, CD4+CD28+/CD4+ T cells, CD4+CD28+ T cells, CD8+CD28+/CD8+ T cells, CD8+HLA-DR+/CD8+ T cells, CD8+HLA-DR+ T cells T cells, CD8+CD38+/CD8+ T cells, CD8+CD38+ T cells and CD4+/CD8+ T cells than those in controls. The percentages of specific lymphocyte subtypes were significantly different in cancer patients versus healthy individuals. For instance, cancer patients had lower levels of B cells, CD4+ T cells, naïve CD4+/CD4+ T cells, naïve CD4+ T cells, CD4+CD28+ T cells, CD8+CD28+ T cells and higher levels of NK cells, white blood cells (WBC), monocytes, neutrophils, eosinophils, basophils, monocytes to lymphocyte ratio (MLR), neutrophils to lymphocyte ratio (NLR), eosinophil to lymphocyte ratio (ELR), basophil to lymphocyte ratio (BLR), and blood platelet to lymphocyte ratio (PLR).

CONCLUSIONS

Abnormal T cell levels can be used as an independent predictive biomarker for noninvasive early screening in NSCLC occurrence and progression.

Immune activation markers in individuals with HIV-1 disease and their correlation with HIV-1 RNA levels in individuals on antiretroviral therapy

Background

Currently CD4+ T lymphocyte counts and HIV-1 RNA levels are being utilized to predict outcome of human immunodeficiency virus (HIV) disease. Recently, the role of immune activation in HIV disease progression and response to treatment is being investigated. This study focused on the expression of CD38 and HLA-DR on lymphocyte subsets in various groups of HIV-infected individuals and to determine their association with HIV-1 disease progression.

Methods

Ninety-eight cases of patients with HIV/AIDS in different disease stages and twenty-four healthy HIV-negative individuals were included in the cross-sectional study. Their immune function and abnormal immune activation markers (CD38 & HLA-DR) were detected using a flowcytometer, and HIV-1 RNA levels in individuals receiving antiretroviral drugs were estimated.

Results

The immune activation marker levels were significantly different between patients with different disease stages (P < 0.001). A significant negative correlation was observed between peripheral blood CD4+ T cell counts and immune activation markers. Also, a significant positive correlation was observed between HIV-1 RNA levels and CD38+CD8+ T lymphocyte.

Conclusion

Immune activation markers (CD38 & HLA-DR) increase with disease progression. CD38+ on CD8+ T lymphocyte correlates well with HIV1 RNA levels in individuals failing on antiretroviral therapy.

Circulating activated lymphocyte subsets as potential blood biomarkers of cancer progression

The objective of this study was to predict the value of lymphocyte subsets in cancer progression. Peripheral blood was obtained from 327 untreated patients with cancer and 158 healthy volunteers. Levels of lymphocyte subsets were determined by flow cytometry. There were decreased levels of natural killer (NK) cells, CD8⁺ T cells, and naïve CD4⁺/CD4⁺ T cells in untreated patients with cancer compared to those in healthy controls. Inversely, there were elevated levels of the following T‐cell percentages in cancer patients compared to those in healthy controls: memory CD4⁺/CD4⁺, CD8⁺ T cells, HLA‐DR/CD8⁺, CD8⁺ CD38⁺/CD8⁺, and CD4⁺/CD8⁺. In addition, there are a decreasing trend in terms of CD4⁺ T‐cell counts and an increase CD8⁺ HLA‐DR/CD8⁺ T‐cell and CD8⁺ CD38⁺/CD8⁺ T‐cell percentages in the advanced stage. An increasing trend with advanced tumor stage and the percentages of CD8⁺ HLA‐DR/CD8⁺ T cells and CD8⁺ CD38⁺/CD8⁺ T cells was shown in this study. There are a negative correlation for CD4⁺ T‐cell counts and positive correlation for percentages of CD8⁺ HLA‐DR/CD8⁺ T cell and CD8⁺ CD38⁺/CD8⁺ T cells with the lymph node metastasis. In the presence of distant metastatic spread, we observed higher NK‐cell counts, CD8⁺ HLA‐DR/CD8⁺ T‐cell percentages, CD8⁺ CD38⁺/CD8⁺ T‐cell percentages, as well as lower CD4⁺ T‐cell counts than those in the absence of distant metastases spread. Abnormal levels of NK cell, CD8⁺ T cells, memory CD4⁺/CD4⁺, naïve CD4⁺/ CD4⁺, CD8⁺ HLA‐DR/CD8⁺, CD8⁺ CD38⁺/CD8⁺, and CD4⁺/CD8⁺ can be a potential blood biomarkers of cancer development. CD4+ T‐cell counts and percentages of CD8⁺ HLA‐DR/ CD8⁺ and CD8⁺ CD38⁺/ CD8⁺ can predict the cancer progression.

Recent Insights into the HIV/AIDS Pandemic

Etiology, transmission and protection: Transmission of HIV, the causative agent of AIDS, occurs predominantly through bodily fluids. Factors that significantly alter the risk of HIV transmission include male circumcision, condom use, high viral load, and the presence of other sexually transmitted diseases. Pathology/Symptomatology: HIV infects preferentially CD4+ T lymphocytes, and Monocytes. Because of their central role in regulating the immune response, depletion of CD4+ T cells renders the infected individual incapable of adequately responding to microorganisms otherwise inconsequential. Epidemiology, incidence and prevalence: New HIV infections affect predominantly young heterosexual women and homosexual men. While the mortality rates of AIDS related causes have decreased globally in recent years due to the use of highly active antiretroviral therapy (HAART) treatment, a vaccine remains an elusive goal. Treatment and curability: For those afflicted HIV infection remains a serious illness. Nonetheless, the use of advanced therapeutics have transformed a dire scenario into a chronic condition with near average life spans. When to apply those remedies appears to be as important as the remedies themselves. The high rate of HIV replication and the ability to generate variants are central to the viral survival strategy and major barriers to be overcome. Molecular mechanisms of infection: In this review, we assemble new details on the molecular events from the attachment of the virus, to the assembly and release of the viral progeny. Yet, much remains to be learned as understanding of the molecular mechanisms used in viral replication and the measures engaged in the evasion of immune surveillance will be important to develop effective interventions to address the global HIV pandemic.

Flow cytometric characterizations of leukocyte subpopulations in the peripheral blood of northern pig-tailed macaques (Macaca leonina)

Pig-tailed macaques (Macaca nemistrina group) have been extensively used as non-human primate animal models for various human diseases in recent years, notably for AIDS research due to their sensitivity to HIV-1. Northern pig-tailed macaques (M. leonina) are distributed in China and other surrounding Southeast Asia countries. Although northern pig-tailed macaques have been bred on a large scale as experimental animals since 2012, the reference value of normal levels of leukocytes is not available. To obtain such information, 62 blood samples from male and female healthy northern pig-tailed macaques at different ages were collected. The normal range of major leukocyte subpopulations, such as T lymphocytes, B lymphocytes, natural killer (NK) cells, monocytes, and the expression levels of activation or differentiation related molecules (CD38, HLA-DR, CCR5, CD21, IgD, CD80 and CD86) on lymphocytes were analyzed by flow cytometry. The counts of B cells decreased with age, but those of CD8(+) T cells and NK cells and the frequency of CD38(+)HLA-DR(+)CD4(+) T cells were positively correlated with age. The counts of leukocyte subpopulations were higher in males than those in females except for CD4(+) T cells. Males also showed higher expression levels of IgD and CD21 within B cells. This study provides basic data about the leukocyte subpopulations of northern pig-tailed macaques and compares this species with commonly used Chinese rhesus macaques (M. mulatta), which is meaningful for the biomedical application of northern pig-tailed macaques.

Immune activation and viral replication after vaccination with an influenza A H1N1 2009 vaccine in HIV-infected children receiving antiretroviral therapy

Immunization with a pandemic influenza A H1N1 2009 was recommended for HIV-infected patients. However, there is limited information concerning the impact of immunization with this vaccine on immune activation and HIV viral replication. In this study, 45 HIV-infected children and adolescents receiving antiretroviral therapy were immunized with a 2-dose series of nonadjuvated monovalent influenza A H1N1 2009 vaccine upon enrollment and approximately 1 month later. Immunogenicity was determined by haemagglutination inhibition assay. The level of immune activation was determined by identification of CD38 and HLA-DR on CD8+ T cells. Patients were divided into 2 groups which include patients who had an undetectable HIV viral load (HIV detectable group) and patients who show virological failure (HIV nondetectable group). The results showed seroconversion rate of 55.2% in HIV nondetectable group, whereas 31.3% was found in HIV detectable group. Both groups of patients showed no major increase in immune activation after immunization. Interestingly, a decrease in the frequency of CD8+ T cells that coexpressed CD38 and HLA-DR was observed after immunization in both groups of patients. We suggested that immunization with influenza A H1N1 2009 vaccine can induce immune response to the pandemic virus without major impact on HIV viral replication and immune activation.

HIV-1 replication in HIV-infected individuals is significantly reduced when peripheral blood mononuclear cells are superinfected with HSV-1

Herpes simplex virus (HSV) can cause generalized infection in human immunodeficiency virus- (HIV-) infected patients leading to death. This study investigated HSV-1 replication in PBMCs from 25 HIV-infected individuals and 15 healthy donors and the effects of HSV-1 superinfection on HIV-1 production. Herpes viral entry mediator (HVEM) receptor on T lymphocytes was also evaluated. Our results confirmed that the number of activated (CD3+ and CD38+) T lymphocytes in HIV-infected individuals (46.51 ± 17.54%) was significantly higher than in healthy donors (27.54 ± 14.12%, P value = 0.001) without any significant differences in HVEM expression. Even though the percentages of HSV-1 infected T lymphocytes between HIV-infected individuals (79.25 ± 14.63%) and healthy donors (80.76 ± 7.13%) were not different (P value = 0.922), yet HSV-1 production in HIV-infected individuals (47.34 ± 11.14 × 10³ PFU/ml) was significantly greater than that of healthy donors (34.17 ± 8.48 × 10³ PFU/ml, P value = 0.001). Moreover, HSV-1 virions were released extracellularly rather than being associated with the cells, and superinfection of HSV-1 at a multiplicity of infection (MOI) of 5 significantly decreased HIV production (P value < 0.001).

A novel 8-color flow cytometry panel to study activation, maturation and senescence of CD4 and CD8 T lymphocytes in HIV-infected individuals at different stages of disease

Multicolor flow cytometry allows to study the markers differentially expressed during maturation, activation, function and senescence on immune cells. Despite the availability of reagents and technology, scarce agreement has been gained regarding phenotypic markers of HIV disease progression other than CD4 T-cell count. In this work, we present a novel high-throughput global analysis of CD4 and CD8 T-lymphocyte profiles by standardized 8-color combinations of antibodies aimed at analyzing HIV disease course progression. For this purpose, two tubes with lyophilized reagent cocktails (CD4- and CD8-specific tubes) were designed to compare the immunological characteristics of HIV-infected persons (37 "high CD4" HAART-treated and 32 "low CD4" naïve or failed-treatment patients) with healthy donors (HD). In particular, T-cell activation (CD25, CD38, CD69), differentiation (CD45RA, CCR7), apoptosis (CD95) and immune suppression profiles (CD25(high)CD127-) in HIV+ patients were compared with HD. Statistical analysis was performed by identifying the parameters associated with disease progression, namely markers that were found to be significantly different between groups with high CD4 counts (including HD) and low CD4 counts (restricted to HIV patients) but not between the HD and the "high CD4" group. This set of markers, including those identifying different maturation and senescence subtypes of CD4 and CD8 T cells, was found to be associated with therapy failure, and it is in fact evaluated in an ongoing study aimed to verify its prognostic value. This robust assay was found feasible on a semi-routine scale for HIV-infected persons, and allows for broader clinical studies aimed at defining markers associated with treatment outcome, possibly having a high impact on the clinical management of HIV disease.

Constitutive activation and accelerated maturation of peripheral blood T cells in healthy adults in Burkina Faso compared to Germany: the case of malaria?

OBJECTIVE

It is not exactly known how frequent exposure to Plasmodium falciparum shapes the peripheral blood T-cell population in healthy West Africans.

METHODS

The frequency of peripheral blood CD4(+) lymphocytes responding to Plasmodium falciparum merozoite surface protein 1 (PfMSP-1) by production of interferon-gamma (IFN-γ), interleukin-2 (IL-2) or tumor necrosis factor-alpha (TNF-α) was determined using a commercially available flow cytometric activation assay (FastImmune) in 17 healthy adults in Nouna, Burkina Faso. T-cell activation and maturation in peripheral blood of healthy adults in Burkina Faso (n=40) and Germany (n=20) were compared using immunophenotyping and three-colour flow cytometry.

RESULTS

Significant numbers of PfMSP-1 -specific CD4(+) lymphocytes producing IFN-γ, IL-2 and/or TNF-α were detected in 14 healthy adults in Nouna. Cytokine profiles showed predominant production of IFN-γ and TNF-α. Compared to Germans, Burkinabé showed markedly lower proportions of CCR7+ CD45RA+ naive CD4(+) cells and slightly higher frequencies of CD95(+)CD4(+) T-cells and of CD38(+) CD8(+) T-cells. The median antibody-binding capacity of CD95(dim) CD4(+) T-cells in Burkinabé was more than twice the value observed in Germans (263 vs. 108 binding sites per cell, p<0.0001).

CONCLUSIONS

We hypothesize that an IFN-γ-induced increase in the expression level of CD95 on CD4(+) lymphocytes may lower the activation threshold of resting naive CD4(+) T-cells in healthy adults living in Burkina Faso. Bystander activation of these cells deserves further study as a molecular mechanism linking strong IFN-γ responses against Plasmodium falciparum to decreased susceptibility to parasitemia observed in specific ethnic groups in West Africa.

Decentralised CD38 activation monitoring: aspects of practical implementation and standardisation

BACKGROUND

In light of the HIV pandemic, significant strides have been made in improving treatment options for patients. Technologies to monitor the progress of a patient on such treatment have therefore also been scaled up. Immune activation as measured by CD38 mean fluorescence intensity (MFI) on CD8 T cells has been successfully shown in a clinical trial to predict response to antiretroviral therapy (ART) and reported as a cost effective real time test to supplement more costly VL testing. In this study we report transfer of this technology from the research into the routine environment.

METHODS

This study was conducted in 2 parts: Firstly, fresh random samples (n=75) were tested at four time intervals (0, 24, 36 and 48 h) post-venesection to review reproducibility of CD38 MFI expression. Secondly, the CD38 MFI assay was introduced into a pilot regional testing facility and random samples (n=40) were validated against values obtained on matched samples tested at the reference laboratory.

RESULTS

The CD38 assay showed acceptable accuracy and reproducibility up to 36 h (98% similarity) after venesection with some reduction in CD38 MFI to 94% at 48 h (bias<0.2MFI, %CV<5). Implementation at the secondary testing site was successful with 98% similarity (% SIM CV<5%) compared to the reference laboratory.

CONCLUSION

The assay proved stable over time and could be tested until 48 h after venesection with no loss of CD38 MFI. Off-site implementation also proved successful, as such, the CD38 assay offers a reliable real time supplementary test to long-term VL monitoring of HIV infected patients on the national ART programme.

Immune Reconstitution During the First Year of Antiretroviral Therapy of HIV-1-Infected Adults in Rural Burkina Faso

There are no data on the outcome of highly active antiretroviral therapy (HAART) in HIV-infected adults in rural Burkina Faso. We therefore assessed CD4⁺ T-cell counts and HIV-1 plasma viral load (VL), the proportion of naive T-cells (co-expressing CCR7 and CD45RA) and T-cell activation (expression of CD95 or CD38) in 61 previously untreated adult patients from Nouna, Burkina Faso, at baseline and 2 weeks, 1, 3, 6, 9 and 12 months after starting therapy. Median CD4⁺ T-cell counts increased from 174 (10^th-90^th percentile: 33-314) cells/µl at baseline to 300 (114- 505) cells/µl after 3 months and 360 (169-562) cells/µl after 12 months of HAART. Median VL decreased from 5.8 (4.6- 6.6) log10 copies/ml at baseline to 1.6 (1.6-2.3) log10 copies/ml after 12 months. Early CD4⁺ T-cell recovery was accompanied by a reduction of the expression levels of CD95 and CD38 on T-cells. Out of 42 patients with complete virological follow-up under HAART, 19 (45%) achieved concordant good immunological (gain of ≥100 CD4⁺ T-cells/µl above baseline) and virological (undetectable VL) responses after 12 months of treatment (intention-to-treat analysis). Neither a decreased expression of the T-cell activation markers CD38 and CD95, nor an increase in the percentage of naive T-cells reliably predicted good virological treatment responses in patients with good CD4⁺ T-cell reconstitution. Repeated measurement of CD4⁺ T-cell counts during HAART remains the most important parameter for immunologic monitoring. Substitution of repeated VL testing by determination of T-cell activation levels (e.g., CD38 expression on CD8⁺ T-cells) should be applied with caution.

Activation and maturation of peripheral blood T cells in HIV-1-infected and HIV-1-uninfected adults in Burkina Faso: a cross-sectional study

Background

We wanted to explore to what extent environmental exposure to immune stimulants, which is expected to be more present in rural than in urban settings, influences T cell activation and maturation in healthy and in HIV-1-infected individuals in Burkina Faso in west Africa.

Methods

The proportion of circulating naïve T cells and the expression of the T cell activation markers, CD95 and CD38, were analyzed by immunophenotyping and three-colour flow cytometry in 63 healthy individuals and 137 treatment-naïve HIV-1-infected subjects from Ouagadougou (urban setting) and 26 healthy adults and 61 treatment-naïve patients from Nouna (rural).

Results

A slightly higher activation level of CD4⁺ and CD8⁺ peripheral blood T cells was seen in healthy adults living in Nouna than in those living in Ouagadougou. The percentages of naïve CD45RA^bright CCR7⁺ T cells were not significantly different between both study sites. Taking into consideration that relatively more HIV-1-infected patients in Nouna were in an advanced disease stage, no relevant differences were seen in T cell activation and maturation between patients at both study sites. As expected, the percentage of CD95⁺ CD4⁺ and CD38⁺ CD8⁺ T cells and the respective antigen density on these cells was significantly higher in patients than in controls in both settings. The percentage of naïve CD8⁺ T cells was lower in HIV-1-infected subjects than in healthy controls irrespective of the study site, while a lower proportion of naïve CD4⁺ T cells in patients compared with controls was seen only in Nouna.

Conclusions

Environmentally triggered immune activation may contribute to the increased expression of the activation markers CD95 and CD38 on peripheral blood T cells from healthy adults living in rural versus urban settings in Burkina Faso. T cell activation is further increased in HIV-1-infected individuals due to T cell loss and high plasma viral load levels. The observed variations in T cell activation levels or the proportion of naïve T cells in our study patients, however, are not explained by differences in CD4⁺ T cell counts or HIV-1 plasma viral load levels alone.

Elevated CD8 counts during HAART are associated with HIV virologic treatment failure

OBJECTIVE

To evaluate whether elevated CD8 counts are associated with increased risk of virologic treatment failure in HIV-infected individuals.

DESIGN

Retrospective cohort study.

METHODS

US Military HIV Natural History Study participants who initiated highly active antiretroviral therapy (HAART) in 1996-2008 had 6- and 12-month post-HAART HIV RNA <400 copies per milliliter, ≥ 2 subsequent HIV viral loads and a baseline CD8 count were eligible (n = 817). Baseline was 12 months after the start of HAART, virologic failure (VF) was defined as confirmed HIV RNA ≥ 400 copies per milliliter, and CD8 counts ≥ 1200 cells per cubic millimeter were considered elevated. Cox models were used to examine the effect of baseline and time-updated CD8 counts on VF.

RESULTS

There were 216 failures for a rate of 5.6 per 100 person-years [95% confidence interval (CI): 4.9 to 6.4]. Among those initiating HAART in 2000-2008, the participants with elevated baseline CD8 counts had significantly greater risk of VF compared with those with baseline CD8 counts ≤ 600 cells per cubic millimeter [hazard ratio (HR) = 2.68, 95% CI: 1.13 to 6.35]. The participants with elevated CD8 counts at >20% of previous 6-month follow-up visits had a greater risk of failure at the current visit than those who did not (HR = 1.53, 95% CI: 1.14 to 2.06). Those with CD8 counts that increased after the start of HAART had a greater risk of failure than those with CD8 counts that decreased or remained the same (HR = 1.59, 95% CI: 1.19 to 2.13).

CONCLUSIONS

Initial or serial elevated CD8 counts while on HAART or an increase in CD8 counts from HAART initiation may be early warnings for future treatment failure.

Comparative transcriptomics of extreme phenotypes of human HIV-1 infection and SIV infection in sooty mangabey and rhesus macaque

High levels of HIV-1 replication during the chronic phase of infection usually correlate with rapid progression to severe immunodeficiency. However, a minority of highly viremic individuals remains asymptomatic and maintains high CD4⁺ T cell counts. This tolerant profile is poorly understood and reminiscent of the widely studied nonprogressive disease model of SIV infection in natural hosts. Here, we identify transcriptome differences between rapid progressors (RPs) and viremic nonprogressors (VNPs) and highlight several genes relevant for the understanding of HIV-1-induced immunosuppression. RPs were characterized by a specific transcriptome profile of CD4⁺ and CD8⁺ T cells similar to that observed in pathogenic SIV-infected rhesus macaques. In contrast, VNPs exhibited lower expression of interferon-stimulated genes and shared a common gene regulation profile with nonpathogenic SIV-infected sooty mangabeys. A short list of genes associated with VNP, including CASP1, CD38, LAG3, TNFSF13B, SOCS1, and EEF1D, showed significant correlation with time to disease progression when evaluated in an independent set of CD4⁺ T cell expression data. This work characterizes 2 minimally studied clinical patterns of progression to AIDS, whose analysis may inform our understanding of HIV pathogenesis.

Good cell, bad cell: flow cytometry reveals T-cell subsets important in HIV disease

Flow cytometry is a key technology in the study of HIV disease. In this article, we review various cellular markers that can be measured in the setting of pathogenesis or vaccination studies, including markers of activation, differentiation, senescence, immune suppression, and function. In addition, we discuss important considerations for making these measurements. Finally, we examine how flow cytometry studies have taught researchers about the disease process, and the potential for flow cytometry technology to guide treatment decisions and evaluate vaccine candidates in the future.

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.

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.

Microarray analysis of lymphatic tissue reveals stage-specific, gene expression signatures in HIV-1 infection

Untreated HIV-1 infection progresses through acute and asymptomatic stages to AIDS. Although each of the three stages has well-known clinical, virologic, and immunologic characteristics, much less is known of the molecular mechanisms underlying each stage. In this study, we report lymphatic tissue microarray analyses, revealing for the first time stage-specific patterns of gene expression during HIV-1 infection. We show that although there is a common set of key genes with altered expression throughout all stages, each stage has a unique gene expression signature. The acute stage is most notably characterized by increased expression of hundreds of genes involved in immune activation, innate immune defenses (e.g., RIG-1, MDA-5, TLR7 and TLR8, PKR, APOBEC3B, 3F, 3G), adaptive immunity, and in the proapoptotic Fas-Fas ligand pathway. Yet, quite strikingly, the expression of nearly all acute stage genes return to baseline levels in the asymptomatic stage, accompanying partial control of infection. This transition from acute to asymptomatic stage is tied to increased expression of a diverse array of immunosuppressive genes (e.g., CLEC12B, ILT4, galectin-3, CD160, BCMA, FGL2, LAG3, GPNMB). In the AIDS stage, decreased expression of numerous genes involved in T cell signaling identifies genes contributing to T cell dysfunction. These common and stage-specific gene expression signatures identify potential molecular mechanisms underlying the host response and the slow, natural course of HIV-1 infection.

CD38 expression on CD8 T cells has a weak association with CD4 T-cell recovery and is a poor marker of viral replication in HIV-1-infected patients on antiretroviral therapy

OBJECTIVE

The aim of the study was to determine whether the expression of CD38 on CD8 T cells can identify patients with virological failure on antiretroviral therapy (ART).

DESIGN

This was a cross-sectional study of patients attending a single HIV clinic in London.

METHODS

The expression of CD38 on CD8 T cells was assessed using a biologically calibrated flow cytometry protocol. Patients were characterized by lymphocyte subset and viral load measurements. Characteristics including historical CD4 T cell counts, therapeutic history, co-infections and demographics were obtained from medical records.

RESULTS

Elevated levels of CD8 CD38(high) T cells were found in HIV-1-infected patients who failed to suppress viral replication with ART; however, this parameter lacked sufficient sensitivity and specificity to replace viral load testing in assessing the efficacy of ART. Increased levels of CD8 CD38(high) cells were associated with reduced CD4 T cell counts in HIV-1-infected patients on ART after correcting for known determinants of CD4 T-cell recovery.

CONCLUSIONS

The expression of CD38 on CD8 T cells lacks sufficient sensitivity and specificity to be used as a surrogate marker for viral load to monitor HIV-1 infection. T-cell activation is associated with reduced CD4 T-cell reconstitution in patients receiving ART.

Immunophenotypic alterations in acute and early HIV infection

To understand the extent of immune dysregulation in primary HIV infection (PHI) and the impact of antiretroviral therapy (ART) on restoring these abnormalities, we longitudinally evaluated 52 subjects (Acute-Treated (AT); Early-Treated (ET); Early Untreated (EU)) for markers of activation, proliferation, and function on T cells. ET and AT patients differed by 0.54 log viral load (VL) at baseline but did not differ thereafter by more than 0.34 log10 VL. AT subjects had higher CD8(+) T cell counts and expression of markers indicative of CD8(+) T cell activation (CD38), and proliferation (Ki67), at baseline, than ET subjects but were not different 48 weeks post-ART. Although acute PHI is marked by higher level of immune activation than early PHI, virologic and immunologic responses were similar post-ART, suggesting that the extent of immunologic recovery is not negatively impacted by a delay of treatment beyond the acute stage of disease.

Structure and functional regulation of the CD38 promoter

CD38 has multiple roles in biology, including T lymphocyte signaling, neutrophil migration, neurotransmission, cell proliferation, apoptosis, and bone remodeling. To study the transcriptional control of the CD38 gene, we cloned a putative 1.8 kb promoter fragment from a rabbit genomic DNA library. Primer extension analysis indicated two transcription start sites consistent with the absence of a TATA box. Sequence analysis revealed several AP-1, AP-4, myo-D, GATA, and SP-1 sequences. MC3T3.E1 (osteoblast) or RAW-C3 (osteoclast precursor macrophage) cells were then transfected with the CD38 promoter or its deletion fragments ligated to the luciferase reporter gene. Except for the shortest 41 bp fragment, all fragments showed significant luciferase activity. There was a marked stimulation of basal activity in the 93 bp fragment that contained a GC box and SP-1 site. Furthermore, there were significant differences in the activity of the fragments in MC3T3.E1 and RAW-C3 cells. Intracellular Ca(2+) elevations by ionomycin (10muM) in MC3T3.E1 cells inhibited promoter activity, except in the short 41 bp. In contrast, cAMP elevation by exposure to forskolin (100 microM) inhibited activation of all fragments, except the 0.6 and 1.2kb fragments. Finally, TNF-alpha stimulated promoter activity in RAW-C3 cells transfected with the 93 bp and 1.0 kb fragments, consistent with the stimulation of CD38 mRNA by TNF-alpha. Physiologically, therefore, modulation of the expression of the NAD(+)-sensing enzyme, CD38, by Ca(2+), cAMP, and cytokines, such as TNF-alpha may contribute to coupling the intense metabolic activity of osteoclasts and osteoblasts to their respective bone-resorbing and bone-forming functions.

Relationship between CD38 expression on peripheral blood T-cells and monocytes, and response to antiretroviral therapy: A one-year longitudinal study of a cohort of chronically infected ART-naive HIV-1+ patients

BACKGROUND

HIV-1 infection has been associated with high expression of CD38 on peripheral blood (PB) CD8+ and CD4+ T-cells, which has been related with poor prognosis in untreated HIV-1+ patients. In turn, CD38 expression on PB monocytes from HIV-1+ individuals and its behavior after starting antiretroviral therapy (ART) have been poorly studied.

METHODS

CD38 expression on PB CD8+ and CD4+ T-lymphocytes and monocytes was prospectively analyzed in 30 ART-naive HIV-1+ patients, using a quantitative multiparameter flow cytometry approach. Patients were tested prior to therapy, and at weeks +2, +4, +8, +12, and +52 after ART.

RESULTS

Prior to ART, CD38 expression was significantly increased on PB CD8+ and CD4+ T-cells and monocytes; despite a significant decrease after ART, CD38 expression remained abnormally high on PB CD8+ T-cells and monocytes, even after one year of therapy, in the absence of detectable plasma viral load. The ART-induced early changes on CD38 expression by PB T-cells and monocytes differed among the cell subsets analyzed and patient groups, probably reflecting an interaction between the direct effects of therapy and a redistribution of the PB compartments of T-cells and monocytes. Hierarchical clustering analysis showed that the overall pattern of changes in CD38 expression observed early after starting ART was predictive of a better response to therapy, not only for PB CD8+ T-cells, but also for CD4+ T-cells and monocytes. Accordingly, those HIV-1+ patients, who experienced a more pronounced increase in CD38 expression on both PB CD4+ T-cells and monocytes after 2 weeks of ART, showed a more rapid viral clearance, which might reflect decreased HIV-1 replication in lymph nodes and other tissues, and a partial restoration of hematopoiesis.

CONCLUSIONS

Combined quantitative measurement of CD38 expression on PB monocytes, and CD8+ and CD4+ T-cells is a more useful tool for monitoring HIV-1+ patients under ART, rather than quantitation of CD38 expression on PB CD8+ T-lymphocytes alone.