Eugenio Nelson Cavallari

Reconstitution of Intestinal CD4 and Th17 T Cells in Antiretroviral Therapy Suppressed HIV-Infected Subjects: Implication for Residual Immune Activation from the Results of a Clinical Trial

Introduction During HIV infection the severe depletion of intestinal CD4+ T-cells is associated with microbial translocation, systemic immune activation, and disease progression. This study examined intestinal and peripheral CD4+ T-cell subsets reconstitution under combined antiretroviral therapy (cART), and systemic immune activation markers. Methods This longitudinal single-arm pilot study evaluates CD4+ T cells, including Th1 and Th17, in gut and blood and soluble markers for inflammation in HIV-infected individuals before (M0) and after eight (M8) months of cART. From January 2010 to December 2011, 10 HIV-1 naïve patients were screened and 9 enrolled. Blood and gut CD4+ T-cells subsets and cellular immune activation were determined by flow-cytometry and plasma soluble CD14 by ELISA. CD4+ Th17 cells were detected in gut biopsies by immunohistochemistry. Microbial translocation was measured by limulus-amebocyte-lysate assay to detect bacterial lipopolysaccharide (LPS) and PCR Real Time to detect plasma bacterial 16S rDNA. Results Eight months of cART increased intestinal CD4+ and Th17 cells and reduced levels of T-cell activation and proliferation. The magnitude of intestinal CD4+ T-cell reconstitution correlated with the reduction of plasma LPS. Importantly, the magnitude of Th17 cells reconstitution correlated directly with blood CD4+ T-cell recovery. Conclusion Short-term antiretroviral therapy resulted in a significant increase in the levels of total and Th17 CD4+ T-cells in the gut mucosa and in decline of T-cell activation. The observation that pre-treatment levels of CD4+ and of CD8+ T-cell activation are predictors of the magnitude of Th17 cell reconstitution following cART provides further rationale for an early initiation of cART in HIV-infected individuals. Trial Registration ClinicalTrials.gov NCT02097381

Apoptotic epitope-specific CD8+ T cells and interferon signaling intersect in chronic hepatitis C virus infection

CD8(+) T cells specific to caspase-cleaved antigens derived from apoptotic T cells represent a principal player in chronic immune activation. Here, we found that both apoptotic epitope-specific and hepatitis C virus (HCV)-specific CD8(+) T cells were mostly confined within the effector memory (EM) or terminally differentiated EM CD45RA(+) cell subsets expressing a dysfunctional T-helper 1-like signature program in chronic HCV infection. However, apoptotic epitope-specific CD8(+) T cells produced tumor necrosis factor α and interleukin 2 at the intrahepatic level significantly more than HCV-specific CD8(+) T cells, despite both populations expressing high levels of programmed death 1 receptor. Contextually, only apoptotic epitope-specific CD8(+) T cells correlated with both interferon-stimulated gene levels in T cells and hepatic fibrosis score. Together, these data suggest that, compared with HCV-specific CD8(+) T cells, apoptotic epitope-specific CD8(+) T cells can better sustain chronic immune activation, owing to their capacity to produce tumor necrosis factor α, and exhibit greater resistance to inhibitory signals during chronic HCV infection.

Dominant enrichment of phenotypically activated CD38+HLA‐DR+CD8+ T cells, rather than CD38+HLA‐DR+CD4+ T cells, in HIV/HCV coinfected patients on antiretroviral therapy

HIV infection may enhance immune‐activation, while little is known regarding the role of HCV infection. This study investigates the impact of HCV in HIV coinfected patients with undetectable viraemia under HAART on the levels of peripheral T cells immune‐activation. We determined T lymphocytes subsets to characterize immune‐activation defined as CD38 and/or HLA‐DR expression in chronic monoinfected HCV, HIV, and HIV/HCV coinfected subjects. One hundred and fifty six patients were divided into three groups: (i) 77 HIV+ patients; (ii) 50 HCV+ patients; and (iii) 29 coinfected HIV/HCV patients. The level of CD4+ was significantly higher in HCV+ than in HIV+ or in coinfected HIV/HCV subjects. The frequencies of CD4+CD38+/HLA‐DR‐, CD4+CD38‐/HLA‐DR+ and CD4+CD38+/HLA‐DR+ in HIV+ patients were comparable to those measured in coinfected patients, but statistically higher than those observed in HCV+ subjects. The percentage of CD8+ was comparable in HIV‐1+ patients and coinfected HIV/HCV but the results obtained in both groups were significantly higher compared to the results obtained in HCV patients. The level of CD8+CD38+/HLA‐DR‐ showed values lower in HIV+ patients than in that monoinfected HCV and coinfected HIV/HCV patients. The frequencies of CD8+CD38‐/HLA‐DR+ were higher in HIV+ patients compared to HCV+ and coinfected HIV/HCV patients. HIV/HCV coinfected group showed highest levels of CD8+CD38+/HLA‐DR+. HIV plays a pivotal role to determine the immune activation in the host. The role of HCV needs of further investigations but our data show that HCV mainly influences the immune‐activation of the pool of CD8, but also probably plays a supporting additive effect on CD4 immune‐activation. J. Med. Virol. 88:1347–1356, 2016.

Impact of High-Dose Multi-Strain Probiotic Supplementation on Neurocognitive Performance and Central Nervous System Immune Activation of HIV-1 Infected Individuals

Background: Gut microbiota has metabolic activity which influences mucosal homeostasis, local and systemic immune responses, and other anatomical systems (i.e., brain). The effects of dysbiosis are still poorly studied in Human Immunodeficiency Virus-1 (HIV-1) positive subjects and insufficient data are available on the impairment of the gut-brain axis, despite neurocognitive disorders being commonly diagnosed in these patients. This study evaluated the impact of a probiotic supplementation strategy on intrathecal immune activation and cognitive performance in combined antiretroviral therapy (cART) treated HIV-1 infected subjects. Methods: Thirty-five HIV-1 infected individuals were included in this study. At baseline (T0) a battery of tests was administered, to evaluate neurocognitive function and a lumbar puncture was performed to determine neopterin concentration in cerebrospinal fluid (CSF), as a marker of Central Nervous System (CNS) immune activation. Subsequently, a subgroup of participants underwent a 6-month course of multi-strain probiotics supplementation; this intervention group was evaluated, after probiotic treatment, with a second lumbar puncture and with repeated neurocognitive tests. Results: At T0, all participants showed impaired results in at least one neurocognitive test and elevated neopterin concentrations in CSF. After supplementation with probiotics (T6), the interventional group presented a significant decrease in neopterin concentration and a significant improvement in several neurocognitive tests. In contrast, no significant modifications were observed in the neurocognitive performance of controls between T0 and T6. The CNS Penetration Effectiveness Score of antiretroviral therapy did not show an influence from any of the investigated variables. Conclusions: Multi-strain probiotic supplementation seems to exert a positive effect on neuroinflammation and neurocognitive impairment in HIV-1 infected subjects, but large trials are needed to support the concept that modulation of the gut microbiota can provide specific neurological benefits in these patients.

Direct-acting antiviral therapy enhances total CD4+ and CD8+ T-cells responses, but does not alter T-cells activation among HCV mono-infected, and HCV/HIV-1 co-infected patients

AIM Chronic immune activation and poor T-cell immune response are strongly associated with disease progression and pathogenesis of both hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-1 infections. Little is known about the impact of anti-HCV Interferon (IFN)-free direct-acting antiviral (DAA) therapy on the systemic T-cells activation and patterns of peripheral T-cells producing pro-inflammatory cytokines. PATIENTS AND METHODS Forty-five subjects including 18 HCV mono-infected, 17 HCV/HIV-1 co-infected patients under antiretroviral therapy (ART), and 10 healthy controls (HCs) were recruited. Blood samples were collected at baseline (T0) and 12 weeks after the end of DAA therapy (T1). Cell phenotypes (CD3, CD4, CD8), activation markers (CD38 and HLA-DR), and frequency of IFN-γ, interleukin (IL)-17, and IL-22 producing CD4+ and CD8+ T-cells were measured by flow cytometry. Plasma levels of related cytokines were also measured by enzyme-linked immunosorbent assay (ELISA). RESULTS Both HCV, and HCV/HIV-1 patients before and after therapy, showed significant higher percentages of any T-cell subset expressing CD38 and/or HLA-DR compared to HCs. No differences were observed in T-cells activation at T1 compared to T0 in patient groups, and when HCV patients were compared to HCV/HIV-1 group (P>0.05). After therapy, the potential of total circulating T helper (Th) and T cytotoxic (Tc) cells producing IFN-γ, IL-17, and IL-22 were increased. Plasma level of IFN-γ at baseline was showed difference compared to HCs, and significantly reduced after therapy (P<0.05). CONCLUSION Total T-cells immune response enhances after therapy, however, the state of immune activation may remain elevated for a longtime after the end of treatment and contribute to post-Sustained Virologic Response (SVR) consequences.

IFN-α promotes rapid human Treg contraction and late Th1-like Treg decrease

Type I IFNs are pleiotropic cytokines that exert concerted activities in the development of antiviral responses. Regulatory T cells represent a physiologic checkpoint in the balance between immunity and tolerance, requiring fine and rapid controls. Here, we show that human regulatory T cells are particularly sensitive to the sequential effects of IFN‐α. First, IFN‐α exerts a rapid, antiproliferative and proapoptotic effect in vitro and in vivo, as early as after 2 d of pegylated IFN/ribavirin therapy in patients with chronic hepatitis C. Such activities result in the decline, at d 2, in circulating regulatory T cell frequency and specifically of the activated regulatory T cell subset. Later, IFN‐based therapy restrains the fraction of regulatory T cells that can be polarized into IFN‐γ‐producing Th1‐like regulatory T cells known to contribute to chronic immune activation in type 1 inflammation. Indeed, Th1‐like regulatory T cell frequency significantly declines after 30 d of therapy in vivo in relation to the persistent decline of relevant IL‐12 sources, namely, myeloid and 6‐sulfo LacNAc‐expressing dendritic cells. This event is recapitulated by experiments in vitro, providing evidence that it may be attributable to the inhibitory effect of IFN‐α on IL‐12‐induced, Th1‐like regulatory T cell polarization. In summary, our results suggest that IFN‐α‐driven, early regulatory T cell depletion contributes to the development of antiviral immunity, ultimately resulting in the resolution of type 1 inflammation.

An epidemiological investigation to reconstruct a probable human immunodeficiency virus -1 transmission network: a case report

BackgroundRecently published studies have highlighted the importance of phylogenetic and phylodynamic analyses in supporting epidemiological investigations to reconstruct the transmission network of human immunodeficiency virus. Here, we report a case of sexual transmission of human immunodeficiency virus type 1 between a man and a woman that marks once more the importance of a tightened collaboration between phylogeny and epidemiology.Case presentationWe describe a case of human immunodeficiency virus type 1 subtype B transmission in a stable Caucasian heterosexual couple. The man was 30 years old and the woman was 21 years old at the time of their presentation to the Department of Public Health and Infectious Diseases of the University of Rome “Sapienza”. The couple reported a history of drug abuse.ConclusionPhylogenetic analysis is a powerful technique that if properly used can prove valuable in research investigations. In the case presented here, a phylogenetic analysis alongside epidemiological evidence allowed us to determine the most probable source of the human immunodeficiency virus infection. The dated tree allowed us to date the transmission event, the time point, and the direction of transmission based on the phylogeny, which agreed with the presumptive time of infection determined from clinical history-taking.