T cell activation but not polyfunctionality after primary HIV infection predicts control of viral load and length of the time without therapy

Highly dampened HIV-specific cytolytic effector T cell responses define viremic non-progression

This study reports on HIV-specific T cell responses in HIV-1 infected Viremic Non-Progressors (VNPs), a rare group of people living with HIV that exhibit asymptomatic infection over several years accompanied by stable CD4+ T cell counts in spite of ongoing viral replication. We attempted to identify key virus-specific functional attributes that could underlie the apparently paradoxical virus-host equilibrium observed in VNPs. Our results revealed modulation of HIV-specific CD4+ and CD8+ effector T cell responses in VNPs towards a dominant non-cytolytic profile with concomitantly diminished degranulation (CD107a+) ability. Further, the HIV specific CD8+ effector T cell response was primarily enriched for MIP-1β producing cells. As expected, concordant with better viral suppression, VCs exhibit a robust cytolytic T cell response. Interestingly, PuPs shared features common to both these responses but did not exhibit a CD4+ central memory IFN-γ producing Gag-specific response that was shared by both non-progressor (VC and VNP) groups, suggesting CD4 helper response is critical for non-progression. Our study also revealed that cytolytic response in VNPs is primarily limited to polyfunctional cells while both monofunctional and polyfunctional cells significantly contribute to cytolytic responses in VCs. To further understand mechanisms underlying the unique HIV-specific effector T cell response described here in VNPs we also evaluated and demonstrated a possible role for altered gut homing in these individuals. Our findings inform immunotherapeutic interventions to achieve functional cures in the context of ART resistance and serious non AIDS events.

The importance of advanced cytometry in defining new immune cell types and functions relevant for the immunopathogenesis of HIV infection

: In the last years, novel, exciting immunological findings of interest for HIV research and treatment were identified thanks to different cytometric approaches. The analysis of the phenotypes and functionality of cells belonging to the immune system could clarify their role in the immunopathogenesis of HIV infection, and to elaborate key concepts, relevant in the treatment of this disease. Important discoveries have been made concerning cells that are important for protective immunity like lymphocytes that display polyfunctionality, resident memory T cells, innate lymphoid cells, to mention a few. The complex phenotype of myeloid-derived suppressor cells has been investigated, and relevant changes have been reported during chronic and primary HIV infection, in correlation with changes in CD4 T-cell number, T-cell activation, and with advanced disease stage. The search for markers of HIV persistence present in latently infected cells, namely those molecules that are important for a functional or sterilizing cure, evidenced the role of follicular helper T cells, and opened a discussion on the meaning and use of different surface molecules not only in identifying such cells, but also in designing new strategies. Finally, advanced technologies based upon the simultaneous detection of HIV-RNA and proteins at the single cell level, as well as those based upon spectral cytometry or mass cytometry are now finding new actors and depicting a new scenario in the immunopathogenesis of the infection, that will allow to better design innovative therapies based upon novel drugs and vaccines.

Short Communication: Circulating Mitochondrial DNA and Lipopolysaccharide-Binding Protein but Not Bacterial DNA Are Increased in Acute Human Immunodeficiency Virus Infection

Microbial translocation has been suggested as a major driver of chronic immune activation HIV infection. Thus, we compared the extent of microbial translocation in patients with acute HIV infection and patients followed after CD4-guided structured treatment interruption (STI) by measuring different circulating markers: (1) lipopolysaccharide (LPS)-binding protein (LBP), (2) bacterial DNA, (3) soluble CD14 (sCD14), and (4) mitochondrial DNA (mtDNA). Bacterial DNA and sCD14 levels were similar in all groups. Patients in acute phase showed higher levels of LBP and mtDNA. In STI, we found a positive correlation between the percentage of CD8+ T cells and bacterial DNA levels. Considering all patients, LBP was positively correlated with the percentage and the absolute count of CD8+ T cells, and with mtDNA stressing the importance of mitochondrial products in sustaining chronic immune activation.

Efficient T-Cell Compartment in HIV-Positive Patients Receiving Orthotopic Liver Transplant and Immunosuppressive Therapy

BACKGROUND

In patients undergoing orthotopic liver transplant (OLT), immunosuppressive treatment is mandatory and infections are leading causes of morbidity/mortality. Thus, it is essential to understand the functionality of cell-mediated immunity after OLT. The aim of the study was to identify changes in T-cell phenotype and polyfunctionality in human immunodeficiency virus-positive (HIV+) and -negative (HIV-) patients undergoing immunosuppressive treatment after OLT.

METHODS

We studied peripheral blood mononuclear cells from 108 subjects divided into 4 groups of 27: HIV+ transplanted patients, HIV- transplanted patients, HIV+ nontransplanted patients, and healthy subjects. T-cell activation, differentiation, and cytokine production were analyzed by flow cytometry.

RESULTS

Median age was 55 years (interquartile range, 52-59 years); the median CD4 count in HIV+ patients was 567 cells/mL, and all had undetectable viral load. CD4+ and CD8+ T-cell subpopulations showed different distributions between HIV+ and HIV- OLT patients. A cluster representing effector cells expressing PD1 was abundant in HIV- transplanted patients and they were characterized by higher levels of CD4+ T cells able to produce interferon-γ and tumor necrosis factor-α.

CONCLUSIONS

HIV- transplanted patients have more exhausted or inflammatory T cells compared to HIV+ transplanted patients, suggesting that patients who have already experienced a form of immunosuppression due to HIV infection respond differently to anti-rejection therapy.

Handling and Processing of Blood Specimens from Patients with COVID-19 for Safe Studies on Cell Phenotype and Cytokine Storm

The pandemic caused by severe acute respiratory syndrome coronavirus 2 heavily involves all those working in a laboratory. Samples from known infected patients or donors who are considered healthy can arrive, and a colleague might be asymptomatic but able to transmit the virus. Working in a clinical laboratory is posing several safety challenges. Few years ago, International Society for Advancement of Cytometry published guidelines to safely analyze and sort human samples that were revised in these days. We describe the procedures that we have been following since the first patient appeared in Italy, which have only slightly modified our standard one, being all human samples associated with risks. © 2020 International Society for Advancement of Cytometry.

Rapid CD4+ T-cell decline is associated with coreceptor switch among MSM primarily infected with HIV-1 CRF01_AE in Northeast China

OBJECTIVE

CRF01_AE is the most prevalent HIV-1 subtype among MSM in China. However, the characteristics and underlying mechanism of the accelerated CD4 T-cell decline in CRF01_AE-infected MSM remain incompletely understood.

DESIGN

A long-term prospective follow-up study was conducted with 1388 MSM at risk of HIV-1 infection in Northeast China. MSM with primary HIV-1 CRF01_AE infection were identified and followed for 3-6 years to explore the determinants of rapid CD4 T-cell decline.

METHODS

Tropism was determined in primary infection by both single genome amplification-based genotypic prediction using four different algorithms and phenotypic determination using clinical isolates. Serial isolates were used to determine phenotype of coreceptor switch. Human leukocyte antigen genotypes and T-cell activation markers were determined.

RESULTS

Fifty-nine MSM primarily infected with HIV-1 CRF01_AE were discovered and recruited for the follow-up study. CCR5-utilizing (R5) viruses accounted for up to 98% of HIV-1 CRF01_AE infections in Northeast China. Survival analysis indicated 39.5% of the patients underwent coreceptor switch within 3 years after infection. After adjustment for other potential risk factors, linear mixed-effect models demonstrated patients experienced R5 to CXCR4-utilizing/dual-tropic (X4/DM) coreceptor switch within 3 years after infection underwent a faster CD4 T-cell decline compared to those without coreceptor switch.

CONCLUSIONS

Primary HIV-1 CRF01_AE infection among MSM in Northeast China is characterized by R5 viral infection and early R5 to X4/DM coreceptor switch, which is associated with rapid CD4 T-cell decline. The findings highlight the importance of immediate treatment among the CRF01_AE-infected MSM.

Anti-TNF-α Drugs Differently Affect the TNFα-sTNFR System and Monocyte Subsets in Patients with Psoriasis

TNF-α has a central role in the development and maintenance of psoriatic plaques, and its serum levels correlate with disease activity. Anti-TNF-α drugs are, however, ineffective in a relevant percentage of patients for reasons that are currently unknown. To understand whether the response to anti-TNF-α drugs is influenced by the production of anti-drug antibodies or by the modulation of the TNFα-TNFα receptor system, and to identify changes in monocyte phenotype and activity, we analysed 119 psoriatic patients who either responded or did not respond to different anti-TNF-α therapies (adalimumab, etanercept or infliximab), and measured plasma levels of TNF-α, TNF-α soluble receptors, drug and anti-drug antibodies. Moreover, we analyzed the production of TNF-α and TNF-α soluble receptors by peripheral blood mononuclear cells (PBMCs), and characterized different monocyte populations. We found that: i) the drug levels varied between responders and non-responders; ii) anti-infliximab antibodies were present in 15% of infliximab-treated patients, while anti-etanercept or anti-adalimumab antibodies were never detected; iii) plasma TNF-α levels were higher in patients treated with etanercept compared to patients treated with adalimumab or infliximab; iv) PBMCs from patients responding to adalimumab and etanercept produced more TNF-α and sTNFRII in vitro than patients responding to infliximab; v) PBMCs from patients not responding to infliximab produce higher levels of TNF-α and sTNFRII than patients responding to infliximab; vi) anti- TNF-α drugs significantly altered monocyte subsets. A complex remodelling of the TNFα-TNFα receptor system thus takes place in patients treated with anti-TNF-α drugs, that involves either the production of anti-drug antibodies or the modulation of monocyte phenotype or inflammatory activity.

Th1 and Th17 proinflammatory profile characterizes invariant natural killer T cells in virologically suppressed HIV+ patients with low CD4+/CD8+ ratio

INTRODUCTION

Scanty data exist on the phenotype and functionality of invariant natural killer T (iNKT) cells in HIV-infected (HIV+) patients.

METHODS

By flow cytometry, we studied iNKT cells from 54 HIV+ patients who started combined antiretroviral therapy and had undetectable viral load for more than 1 year. Twenty-five maintained a CD4/CD8 ratio less than 0.4, whereas 29 reached a ratio more than 1.1; 32 age-matched and sex-matched patients were healthy controls (CTR).

RESULTS

Patients with low ratio had lower percentage of CD4 iNKT cells compared with patients with high ratio and higher CD8 iNKT cell percentage; double-negative iNKT cells were lower in HIV+ patients compared with CTR. Patients with low ratio had higher percentage of CD4 and double-negative iNKT cells expressing CD38 and HLA-DR compared with patients with high ratio. CD4 iNKT cells expressing PD-1 were higher in patients with CD4/CD8 ratio less than 0.4, whereas double-negative iNKT cells expressing PD-1 were lower compared with patients with ratio more than 1.1. Patients with low ratio had higher CD4 iNKT cells producing IL-17, CD8 iNKT cells producing IFN-γ, TNF-α or IFN-γ and TNF-α, and double-negative iNKT cells producing IL-17 or IL-17 and IFN-γ compared with CTR. Activated CD4 (or CD8) T cells correlated with activated CD4 (or CD8) iNKT cells, as well as the percentages of CD4 (or CD8) T cells expressing PD-1 was correlated to that of CD4 (or CD8) iNKT cells expressing PD-1.

CONCLUSION

Low CD4/CD8 ratio despite effective combined antiretroviral therapy is associated with altered iNKT cell subsets, enhanced activation, and prominent Th1/Th17 proinflammatory profile.

Innovative Flow Cytometry Allows Accurate Identification of Rare Circulating Cells Involved in Endothelial Dysfunction

Introduction

Although rare, circulating endothelial and progenitor cells could be considered as markers of endothelial damage and repair potential, possibly predicting the severity of cardiovascular manifestations. A number of studies highlighted the role of these cells in age-related diseases, including those characterized by ectopic calcification. Nevertheless, their use in clinical practice is still controversial, mainly due to difficulties in finding reproducible and accurate methods for their determination.

Methods

Circulating mature cells (CMC, CD45^-, CD34⁺, CD133^-) and circulating progenitor cells (CPC, CD45^dim, CD34^bright, CD133⁺) were investigated by polychromatic high-speed flow cytometry to detect the expression of endothelial (CD309⁺) or osteogenic (BAP⁺) differentiation markers in healthy subjects and in patients affected by peripheral vascular manifestations associated with ectopic calcification.

Results

This study shows that: 1) polychromatic flow cytometry represents a valuable tool to accurately identify rare cells; 2) the balance of CD309⁺ on CMC/CD309⁺ on CPC is altered in patients affected by peripheral vascular manifestations, suggesting the occurrence of vascular damage and low repair potential; 3) the increase of circulating cells exhibiting a shift towards an osteoblast-like phenotype (BAP⁺) is observed in the presence of ectopic calcification.

Conclusion

Differences between healthy subjects and patients with ectopic calcification indicate that this approach may be useful to better evaluate endothelial dysfunction in a clinical context.

Levels of circulating endothelial cells are low in idiopathic pulmonary fibrosis and are further reduced by anti-fibrotic treatments

BACKGROUND

It has been suggested that circulating fibrocytes and endothelial cells actively participate in the intense remodelling of the pulmonary vasculature in patients with idiopathic pulmonary fibrosis (IPF). Indeed, fibrotic areas exist that have fewer blood vessels, whereas adjacent non-fibrotic tissue is highly vascularized. The number of circulating endothelial cells (CEC) and endothelial progenitor cells (EPC) might reflect the balance between vascular injury and repair. Thus, fibrocytes as well as endothelial cells could potentially be used as biomarkers of disease progression and treatment outcome.

METHODS

Peripheral blood samples were collected from 67 patients with a multidisciplinary diagnosis of IPF and from 45 age-matched and sex-matched healthy volunteers. Buffy coat was isolated according to standard procedures and at least 20 million cells were stained with different monoclonal antibodies for the detection of CEC, EPC and circulating fibrocytes. For the detection of CEC and EPC, cells were stained with anti-CD45, anti-CD34, anti-CD133, anti-CD14, anti-CD309 and with the viability probe Far-Red LIVE/DEAD. For the detection of circulating fibrocytes, cells were first stained with LIVE/DEAD and the following monoclonal antibodies: anti-CD3, anti-CD19, anti-CD45, anti-CD34 and anti-CD14, then cells were fixed, permeabilized and stained with fluorochrome-conjugated anti-collagen I monoclonal antibodies.

RESULTS

Patients with IPF displayed almost undetectable levels of circulating fibrocytes, low levels of CEC, and normal levels of EPC. Patients treated with nintedanib displayed higher levels of CEC, but lower levels of endothelial cells expressing CD309 (the type II receptor for vascular endothelial growth factor). Treatment with both nintedanib and pirfenidone reduced the percentage of CEC and circulating fibrocytes.

CONCLUSIONS

Levels of CEC were reduced in patients with IPF as compared to healthy individuals. The anti-fibrotic treatments nintedanib and pirfenidone further reduced CEC levels. These findings might help explain the mechanism of action of these drugs and should be explored as predictive biomarkers in IPF.

Magnitude and Kinetics of CD8+ T Cell Activation during Hyperacute HIV Infection Impact Viral Set Point

CD8(+) T cells contribute to the control of HIV, but it is not clear whether initial immune responses modulate the viral set point. We screened high-risk uninfected women twice a week for plasma HIV RNA and identified 12 hyperacute infections. Onset of viremia elicited a massive HIV-specific CD8(+) T cell response, with limited bystander activation of non-HIV memory CD8(+) T cells. HIV-specific CD8(+) T cells secreted little interferon-γ, underwent rapid apoptosis, and failed to upregulate the interleukin-7 receptor, known to be important for T cell survival. The rapidity to peak CD8(+) T cell activation and the absolute magnitude of activation induced by the exponential rise in viremia were inversely correlated with set point viremia. These data indicate that rapid, high magnitude HIV-induced CD8(+) T cell responses are crucial for subsequent immune control of acute infection, which has important implications for HIV vaccine design.

Reliable and accurate CD4+ T cell count and percent by the portable flow cytometer CyFlow MiniPOC and "CD4 Easy Count Kit-Dry", as revealed by the comparison with the gold standard dual platform technology

Background

An accurate and affordable CD4+ T cells count is an essential tool in the fight against HIV/AIDS. Flow cytometry (FCM) is the “gold standard” for counting such cells, but this technique is expensive and requires sophisticated equipment, temperature-sensitive monoclonal antibodies (mAbs) and trained personnel. The lack of access to technical support and quality assurance programs thus limits the use of FCM in resource-constrained countries. We have tested the accuracy, the precision and the carry-over contamination of Partec CyFlow MiniPOC, a portable and economically affordable flow cytometer designed for CD4+ count and percentage, used along with the “CD4% Count Kit-Dry”.

Materials and Methods

Venous blood from 59 adult HIV+ patients (age: 25–58 years; 43 males and 16 females) was collected and stained with the “MiniPOC CD4% Count Kit-Dry”. CD4+ count and percentage were then determined in triplicate by the CyFlow MiniPOC. In parallel, CD4 count was performed using mAbs and a CyFlow Counter, or by a dual platform system (from Beckman Coulter) based upon Cytomic FC500 (“Cytostat tetrachrome kit” for mAbs) and Coulter HmX Hematology Analyzer (for absolute cell count).

Results

The accuracy of CyFlow MiniPOC against Cytomic FC500 showed a correlation coefficient (CC) of 0.98 and 0.97 for CD4+ count and percentage, respectively. The accuracy of CyFlow MiniPOC against CyFlow Counter showed a CC of 0.99 and 0.99 for CD4 T cell count and percentage, respectively. CyFlow MiniPOC showed an excellent repeatability: CD4+ cell count and percentage were analyzed on two instruments, with an intra-assay precision below ±5% deviation. Finally, there was no carry-over contamination for samples at all CD4 values, regardless of their position in the sequence of analysis.

Conclusion

The cost-effective CyFlow MiniPOC produces rapid, reliable and accurate results that are fully comparable with those from highly expensive dual platform systems.

Successful treatment of HIV-1 infection increases the expression of a novel, short transcript for IL-18 receptor α chain

: The importance of interleukin (IL)-18 in mediating immune activation during HIV infection has recently emerged. IL-18 activity is regulated by its receptor (IL-18R), formed by an α and a β chain, the IL-18-binding protein, and the newly identified shorter isoforms of both IL-18R chains. We evaluated gene expression of the IL-18/IL-18R system in peripheral blood mononuclear cells from HIV+ patients. Compared with healthy donors, IL-18 expression decreased in patients with primary infection. The IL-18Rα short transcript expression was strongly upregulated by successful highly active antiretroviral therapy. HIV progression and its treatment can influence the expression of different components of the complex IL-18/IL-18R system.

Age-related differences in polyfunctional T cell responses

Background

A reduced number of naïve T cells along with an accumulation of differentiated cell types in aging have been described but little is known about the polyfunctionality of the T cell responses. In this study we compared the individual and polyfunctional expression of IFN-γ, MIP-1α, TNF-α, perforin, and IL-2 by T cell subsets, including the newly described stem cell like memory T cells (T_SCM), in response to stimulation with superantigen staphylococcal enterotoxin B (SEB) in older (median age 80, n = 23) versus younger (median age 27; n = 23) adults.

Results

Older age was associated with a markedly lower frequency of CD8+ naïve T cells (11% vs. 47%; p < 0.0001) and an expansion in memory T cell subsets including central memory (p < 0.05), effector memory and effector T cells (p < 0.001 for both). There was also a decline in CD4+ naïve T cells in older subjects (33% vs. 45%; p = 0.02). There were no differences in frequencies or polyfunctional profiles of T_SCM between groups. CD8+ naïve cells in the older group had increased expression of all functional parameters measured compared to the younger subjects and exhibited greater polyfunctionality (p = 0.04). CD4+ naïve T cells in the older group also showed greater polyfunctionality with a TNF-α and IL-2 predominance (p = 0.005). CD8+ effector memory and effector T cells exhibited increased polyfunctionality in the older group compared with younger (p = 0.01 and p = 0.003).

Conclusions

These data suggest that aging does not have a negative effect on polyfunctionality and therefore this is likely not a major contributor to the immunesenescence described with aging.

WITHDRAWN: Systems Biology and Immune Aging

The Publisher regrets that this article is an accidental duplication of anarticle that has already been published, http://dx.doi.org/10.1016/j.imlet.2014.09.009. The duplicate article has therefore been withdrawn.

HIV-1-specific CD4(+) responses in primary HIV-1 infection predict disease progression

OBJECTIVES

Immune factors determining clinical progression following HIV-1 infection remain unclear. The SPARTAC trial randomized 366 participants in primary HIV infection (PHI) to different short-course therapies. The aim of this study was to investigate how early immune responses in PHI impacted clinical progression in SPARTAC.

DESIGN AND METHODS

Participants with PHI recruited to the SPARTAC trial were sampled at enrolment, prior to commencing any therapy. HIV-1-specific CD4(+) and CD8(+) ELISpot responses were measured by gamma interferon ELISPOT. Immunological data were associated with baseline covariates and times to clinical progression using logistic regression, Kaplan-Meier plots, and Cox models.

RESULTS

Making a CD4(+) T-cell ELISpot response (n = 119) at enrolment was associated with higher CD4(+) cell counts (P = 0.02) and to some extent lower plasma HIV RNA (P = 0.07). There was no correlation between the number of overlapping Gag CD8(+) T-cell ELISpot responses (n = 138) and plasma HIV-1 RNA viral load. Over a median follow-up of 2.9 years, baseline CD4(+) cell ELISpot responses (n = 119) were associated with slower clinical progression (P = 0.01; log-rank). Over a median of 3.1 years, there was no evidence for a survival advantage imposed by CD8(+) T-cell immunity (P = 0.82).

CONCLUSION

These data support a dominant protective role for CD4(+) T-cell immunity in PHI compared with CD8(+) T-cell responses, and are highly pertinent to HIV pathogenesis and vaccines, indicating that vaccine-induced CD4(+) responses may confer sustained benefit.

Bicistronic DNA vaccines simultaneously encoding HIV, HSV and HPV antigens promote CD8⁺ T cell responses and protective immunity

Millions of people worldwide are currently infected with human papillomavirus (HPV), herpes simplex virus (HSV) or human immunodeficiency virus (HIV). For this enormous contingent of people, the search for preventive and therapeutic immunological approaches represents a hope for the eradication of latent infection and/or virus-associated cancer. To date, attempts to develop vaccines against these viruses have been mainly based on a monovalent concept, in which one or more antigens of a virus are incorporated into a vaccine formulation. In the present report, we designed and tested an immunization strategy based on DNA vaccines that simultaneously encode antigens for HIV, HSV and HPV. With this purpose in mind, we tested two bicistronic DNA vaccines (pIRES I and pIRES II) that encode the HPV-16 oncoprotein E7 and the HIV protein p24 both genetically fused to the HSV-1 gD envelope protein. Mice i.m. immunized with the DNA vaccines mounted antigen-specific CD8⁺ T cell responses, including in vivo cytotoxic responses, against the three antigens. Under experimental conditions, the vaccines conferred protective immunity against challenges with a vaccinia virus expressing the HIV-derived protein Gag, an HSV-1 virus strain and implantation of tumor cells expressing the HPV-16 oncoproteins. Altogether, our results show that the concept of a trivalent HIV, HSV, and HPV vaccine capable to induce CD8⁺ T cell-dependent responses is feasible and may aid in the development of preventive and/or therapeutic approaches for the control of diseases associated with these viruses.

Cytometry, immunology, and HIV infection: three decades of strong interactions

Flow cytometry (FCM) has been extensively used to investigate immunological changes that occur from infection with the human immunodeficiency virus (HIV). This review describes some of the most relevant cellular and molecular changes in the immune system that can be detected by FCM during HIV infection. Finally, it will be discussed how this technology has facilitated the understanding not only of the biology of the virus but also of the mechanisms that the immune system activates to fight HIV and is allowing to monitor the efficacy of antiretroviral therapy.