CD8+CD28-CD127loCD39+ regulatory T-cell expansion: A new possible pathogenic mechanism for HIV infection?

BACKGROUND: HIV-associated immunodeficiency is related to loss of CD4+ T cells. This mechanism does not explain certain manifestations of HIV disease, such as immunodeficiency events in patients with greater than 500 CD4+ T cells/µL. CD8+CD28-CD127loCD39+ T cells are regulatory T (Treg) lymphocytes that are highly concentrated within the tumor microenvironment and never analyzed in the circulation of HIV-infected patients. OBJECTIVES: We sought to analyze the frequency of CD8+CD28-CD127loCD39+ Treg cells in the circulation of HIV-infected patients. METHODS: The frequency of circulating CD8+CD28-CD127loCD39+ Treg cells was analyzed and correlated with viral load and CD4+ T-cell counts/percentages in 93 HIV-1-infected patients subdivided as follows: naive (n = 63), elite controllers (n = 19), long-term nonprogressors (n = 7), and HIV-infected patients affected by tumor (n = 4). The same analyses were performed in HIV-negative patients with cancer (n = 53), hepatitis C virus-infected patients (n = 17), and healthy donors (n = 173). RESULTS: HIV-infected patients had increased circulating levels of functional CD8+CD28-CD127loCD39+ Treg cells. These cells showed antigen specificity against HIV proteins. Their frequency after antiretroviral therapy (ART) correlated with HIV viremia, CD4+ T-cell counts, and immune activation markers, suggesting their pathogenic involvement in AIDS- or non-AIDS-related complications. Their increase after initiation of ART heralded a lack of virologic or clinical response, and hence their monitoring is clinically relevant. CONCLUSION: HIV infection induces remarkable expansion of CD8+CD28-CD127loCD39+ Treg cells, the frequency of which correlates with both clinical disease and signs of chronic immune cell activation. Monitoring their frequency in the circulation is a new marker of response to ART when effects on viremia and clinical response are not met.

Natural killer cells in HIV controller patients express an activated effector phenotype and do not up-regulate NKp44 on IL-2 stimulation.

Control of HIV replication in elite controller (EC) and long-term nonprogressor (LTNP) patients has been associated with efficient CD8(+)cytotoxic T-lymphocyte function. However, innate immunity may play a role in HIV control. We studied the expression of natural cytotoxicity receptors (NKp46, NKp30, and NKp44) and their induction over a short time frame (2-4 d) on activation of natural killer (NK) cells in 31 HIV controller patients (15 ECs, 16 LTNPs). In EC/LTNP, induction of NKp46 expression was normal but short (2 d), and NKp30 was induced to lower levels vs. healthy donors. Notably, in antiretroviral-treated aviremic progressor patients (TAPPs), no induction of NKp46 or NKp30 expression occurred. More importantly, EC/LTNP failed to induce expression of NKp44, a receptor efficiently induced in activated NK cells in TAPPs. The specific lack of NKp44 expression resulted in sharply decreased capability of killing target cells by NKp44, whereas TAPPs had conserved NKp44-mediated lysis. Importantly, conserved NK cell responses, accompanied by a selective defect in the NKp44-activating pathway, may result in lack of killing of uninfected CD4(+)NKp44Ligand(+) cells when induced by HIVgp41 peptide-S3, representing a relevant mechanism of CD4(+) depletion. In addition, peripheral NK cells from EC/LTNP had increased NKG2D expression, significant HLA-DR up-regulation, and a mature (NKG2A-CD57(+)killer cell Ig-like receptor(+)CD85j(+)) phenotype, with cytolytic function also against immature dendritic cells. Thus, NK cells in EC/LTNP can maintain substantially unchanged functional capabilities, whereas the lack of NKp44 induction may be related to CD4 maintenance, representing a hallmark of these patients.

'Emergency exit' of bone-marrow-resident CD34(+)DNAM-1(bright)CXCR4(+)-committed lymphoid precursors during chronic infection and inflammation.

During chronic inflammatory disorders, a persistent natural killer (NK) cell derangement is observed. While increased cell turnover is expected, little is known about whether and how NK-cell homeostatic balance is maintained. Here, flow cytometric analysis of peripheral blood mononuclear cells in chronic inflammatory disorders, both infectious and non-infectious, reveals the presence of a CD34(+)CD226(DNAM-1)(bright)CXCR4(+) cell population displaying transcriptional signatures typical of common lymphocyte precursors and giving rise to NK-cell progenies with high expression of activating receptors and mature function and even to α/ß T lymphocytes. CD34(+)CD226(bright)CXCR4(+) cells reside in bone marrow, hardly circulate in healthy donors and are absent in cord blood. Their proportion correlates with the degree of inflammation, reflecting lymphoid cell turnover/reconstitution during chronic inflammation. These findings provide insight on intermediate stages of NK-cell development, a view of emergency recruitment of cell precursors, and upgrade our understanding and monitoring of chronic inflammatory conditions.

Innate immunity cell activation in virologically suppressed HIV-infected maraviroc-treated patients.

This is a cross-sectional, case-control study analyzing the effect of antiretroviral therapy (ART) including or not maraviroc, on circulating monocytes and natural killer cells. Sixty-eight HIV-positive patients virologically suppressed receiving ART at least 6 months were subdivided as receiving (group 1) or not (group 2) maraviroc in their ART. Frequency of monocytes and natural killer cells, as well as their activation markers, were studied. Modulation of innate immune cells may be differently affected by combined ART.

Relationship between innate immunity, soluble markers and metabolic-clinical parameters in HIV+ patients ART treated with HIV-RNA<50 cp/mL.

INTRODUCTION: The persistence of immune activation and inflammation in HIV patients with HIV-RNA (VL) undetectable causes many co-morbidities [1-3]. The aim of this study is to correlate monocytes (m) and NK cell activation levels, soluble markers and oxidative stress with clinical, biochemical and metabolic data in HIV-1 infected patients with VL≤50 copies (cp)/mL on antiretroviral therapy. MATERIALS AND METHODS: Multicentre, cross-sectional study in patients with VL≤50 cp/mL and on antiretroviral therapy by at least six months. We studied: activation/homing markers (CD38, HLA-DR, CCR-2, PDL-1) on inflammatory, intermediate, proinflammatory m; activatory receptors NKp30, NKp46 and HLA-DR on NK cells; soluble inflammatory (sCD14, adiponectina, MCP-1) and stress oxidative markers (dRoms, antiRoms). Univariate analyses are performed with non-parametric and Pearson tests. The significant correlations were adjusted for possible known confounding factors (smoking, Cytomegalovirus IgG serology, Raltegravir, Protease Inhibitor [PI] therapy and HCV-RNA) with multivariate analysis. RESULTS: In the 68 patients the positive correlation between age and antiRoms was significant also after adjustment for PI use (p=0.05). The% CD8+T was associated with% proinflammatory m (p=0.043) and with their expression of CCR2 mean fluorescence intensity (MFI) (p=0.012). The% NKp46+ was positively correlated with CD4+T count (p=0.001). The fibrinogen was positively associated with dRoms (p=0.052) and the positive correlation between triglycerides and antiRoms has been confirmed (p<0.001); the impact of antiRoms on HDL/triglycerides ratio (p=0.006) was observed after adjustment for PI use. The BMI was associated with smoking (p=0.011). Only the maraviroc-treated patients showed minimal arterial pressure, fibrinogen and antiRoms lower (p=0.001, 0.004 e 0.006) and sCD14 values higher (p=0.029). CONCLUSIONS: Patients with long history of HIV infection and stable immunological and virological status showed interactions between acquired and innate immunity activation; moreover, the levels of some metabolic and inflammatory parameters correlate with oxidative stress values and innate immunity activation. The age, BMI and smoking impact metabolic and immunological parameters. The correlations between antiretroviral drugs and clinical-immunological parameters need further confirmations.

The ligurian human immunodeficiency virus clinical network: a web tool to manage patients with human immunodeficiency virus in primary care and multicenter clinical trials.

BACKGROUND: In recent years, Highly-Active Anti-Retroviral Therapies (HAARTs) have modified the Human Immunodeficiency Virus (HIV) life-cycle and the disease is now considered chronic. Consequently, a longitudinal and complex follow-up is now required for HIV positive patients during their lifetime. Moreover, patients often encounter various complications due to comorbidities, related to the immunodeficiency state and HAARTs' side effects. Thus, HIV positive patients are involved in multicenter clinical trials (MCTs) to improve treatments and discover a preventive vaccine. Therefore, physicians require proper instruments to access comprehensive patient data for managing patients during follow-ups, and tools for data collection and analysis in MCTs. OBJECTIVE: The Ligurian HIV Clinical Network aims to provide physicians with a Web-tool to administrate HIV positive patients' data within primary-care and to reuse the collected clinical information to perform MCTs in Northern Italy. METHODS: The key aspect of the system is a relational database which allows the storage of various types of clinical information (eg, related to HIV, cardiovascular, or hepatic diseases) in multiple formats. The modular design of the database permits a rapid insertion of new parameters without requiring any changes in the database structure. Furthermore, codes from biomedical ontologies controlled vocabularies ("Logical Observation Identifier Names and Codes", and "International Classification of Diseases 9") and ontologies ("Systematized Nomenclature of Medicine Clinical Terms"), units and normality ranges used by all partners participating in the project were collected to achieve a complete semantic interoperability. Accordingly, data can be automatically normalized through the z score formula and physicians can extract and correctly compare information with external statistical tools. Moreover, to respect patients' privacy and legal issues, a local identifier, determined through an HASH cryptography algorithm, is assigned to each patient during the registration process. The database is managed by a user-friendly Web-platform which allows quick access to information during medical examinations and the reusing of the collected data for present and future MCTs. Furthermore, a bidirectional middleware was created in order to import/export information through HL7 messaging. Hence, data can be manually entered by physicians or automatically collected within HL7-compliant Hospital Information systems. RESULTS: Presently, the direct storage of patients' information from the San Paolo Hospital (Savona, Italy), and San Martino and Galliera hospitals in Genoa is in a test phase. Currently, 8 centers of Infectious Diseases (located in Liguria and Piedmont) are participating in the project and almost 400 HIV positive patients have been recorded in the system. Patient data has been used for primary care and research purposes. Currently, there are 4 on-going MCTs and preliminary results have already been presented at International HIV congresses. CONCLUSIONS: The Web-platform allows effective management, sharing and reuse of information within primary care and clinical research. In the future it is planned to share the clinical information from this network with other HL7-compliant workgroups and to extend the platform to other infective diseases (eg, hepatitis).