Intrahepatic Vγ9Vδ2 T-cells from HCV-infected patients show an exhausted phenotype but can inhibit HCV replication.

Hepatitis C virus (HCV) persistence results from inefficiencies of both innate and adaptive immune responses to eradicate the infection. A functional impairment of circulating Vγ9Vδ2 T-cells was described but few data are available on Vγ9Vδ2 T-cells in the liver that, however, represents the battlefield in the HCV/host interaction. Aim of this work was to compare circulating and intrahepatic Vγ9Vδ2 T-cells in chronic HCV-infected patients (HCVpos) and in HCV-negative (HCVneg) subjects. Phenotypic and functional analysis was performed by flow cytometry. Anti-HCV activity was analyzed by using an in vitro autologous liver culture system. Independently from HCV infection, the liver was enriched of Vγ9Vδ2 T-cells expressing an effector/activated phenotype. In contrast, an enrichment of PD-1 expressing Vγ9Vδ2 T-cells was observed both in the peripheral blood and in the liver of HCVpos patients, probably due to a persistent antigenic stimulation. Moreover, a lower frequency of IFN-γ producing Vγ9Vδ2 T-cells was observed in the liver of HCVpos patients, suggesting a functional impairment in the cytokine production in HCVpos liver. Despite this hypo-responsiveness, intrahepatic Vγ9Vδ2 T-cells are able to exert an anti-HCV activity after specific stimulation. Altogether, our data show that HCV infection induced a dysregulation of intrahepatic Vγ9Vδ2 T cells that maintain their anti-HCV activity after specific stimulation. A study aimed to evaluate the mechanisms of the antiviral activity may be useful to identify new pathways able to improve Vγ9Vδ2 T-cells intrahepatic function during HCV infection.

Longitudinal characterization of dysfunctional T cell-activation during human acute Ebola infection.

Data on immune responses during human Ebola virus disease (EVD) are scanty, due to limitations imposed by biosafety requirements and logistics. A sustained activation of T-cells was recently described but functional studies during the acute phase of human EVD are still missing. Aim of this work was to evaluate the kinetics and functionality of T-cell subsets, as well as the expression of activation, autophagy, apoptosis and exhaustion markers during the acute phase of EVD until recovery. Two EVD patients admitted to the Italian National Institute for Infectious Diseases, Lazzaro Spallanzani, were sampled sequentially from soon after symptom onset until recovery and analyzed by flow cytometry and ELISpot assay. An early and sustained decrease of CD4 T-cells was seen in both patients, with an inversion of the CD4/CD8 ratio that was reverted during the recovery period. In parallel with the CD4 T-cell depletion, a massive T-cell activation occurred and was associated with autophagic/apoptotic phenotype, enhanced expression of the exhaustion marker PD-1 and impaired IFN-gamma production. The immunological impairment was accompanied by EBV reactivation. The association of an early and sustained dysfunctional T-cell activation in parallel to an overall CD4 T-cell decline may represent a previously unknown critical point of Ebola virus (EBOV)-induced immune subversion. The recent observation of late occurrence of EBOV-associated neurological disease highlights the importance to monitor the immuno-competence recovery at discharge as a tool to evaluate the risk of late sequelae associated with resumption of EBOV replication. Further studies are required to define the molecular mechanisms of EVD-driven activation/exhaustion and depletion of T-cells.

Evaluation of collected outcome measures in axial spondyloarthritis in daily-care rheumatology settings: the experience of the RHEVER network.

OBJECTIVES: Nowadays, the recommended measures for optimal monitoring of axial Spondyloarthritis (ax-SpA) disease activity are either BASDAI and CRP, or ASDAS-CRP. However, there could be a gap between recommendations and daily practice. We aimed to determine the measures collected by rheumatologists in an ax-SpA follow-up visit, and to determine the impact of a meeting (where rheumatologists reached a consensus on the measures to be collected) on the collection of such measures. METHODS: A consensual meeting of a local network of 32 rheumatologists proposed, four months later, to report at least the BASDAI score in the medical file of every ax-SpA patient at every follow-up visit. An independent investigator reviewed the medical files of 10 consecutive patients per rheumatologist, seen twice during the year (e.g. before and after the meeting). The most frequently collected measures were assessed, and then, the frequency of collection before and after the meeting was compared. RESULTS: A total of 456 medical files from 228 patients were reviewed. Treatment (>60%), CRP (51.3%) and total BASDAI (28.5%) were the most reported measures in medical files. Before/After the meeting, the frequencies of collected measures in medical files were 28.5%/51.7%, 51.3%/52.2%, 16.7%/31.6% and 0.9%/6.1% for BASDAI, CRP, BASDAI + CRP and ASDAS, respectively reaching a statistically significance for BASDAI, ASDAS and BASDAI+CRP (p<0.05). CONCLUSIONS: This study revealed a low rate of systematic report of the recommended outcome measures in ax-SpA. However, it suggests that a consensual meeting involving practicing rheumatologists might be relevant to improve the implementation of such recommendations.

Modulation of polyfunctional HIV-specific CD8 T cells in patients responding differently to antiretroviral therapy.

Antiretroviral therapy allows a restoration of immune cell homeostasis associated with a normal immune competence. Our goal was to analyze the modulation of polyfunctional HIV-specific CD8+ T-cell responses during antiretroviral therapy. HIV-infected individuals were divided into four groups according to CD4+ cell count and viral load at the moment of recruitment. Whole blood was stimulated with a pool of CD8-specific HIV-antigens to assess cytokine/chemokine production and cytotoxicity activity by using flow cytometry. The groups show different modulation in HIV-specific CD8+ T-cell responses. In particular, immunological failure showed different distributions of polyfunctional HIVspecific CD8+ responses, mainly due to an increase of cells producing CD107alpha/IFNgamma/IL-2/MIP-1beta. Our results indicate that this particular 4+ functional subset is a possible correlate of immunological failure. Considering the complexity of interactions among HAART, immune system and HIV, work is in progress to find correlates of therapy efficacy.

HIV impairs CD34+-derived monocytic precursor differentiation into functional dendritic cells.

Dendritic cells (DCs) perform a basic role in the immune system by allowing the initiation of the primary T-cell-dependent immune response. Given previous indirect evidence that DC maturation and function are impaired by HIV, we have developed an in vitro culture system in order to verify the effect of HIV infection on DC function during the development from hematopoietic progenitors. Considering that monocytic (Mo) differentiating cells efficiently replicate monocytotropic HIV, we examined whether HIV-infected monocytic precursors (MoP) were able to generate functional DCs. CD34+ hematopoietic progenitor cells (HPCs) were induced along Mo differentiative pathway in liquid cultures and at an early stage of culture, MoP were infected with M-tropic BaL HIV strain, and after 2 days they were switched to DC differentiation with GM-CSF and IL-4. Derived DCs were actively infected, as detected by HIV-p24 production. HIV did not significantly affect cell viability, but induced a reduction in cell proliferation and an inefficient functional activity in terms of uptake capability and stimulation of allogenic T cells. These results indicate that HIV-infected MoP lost the capacity to generate functional DCs, and this may represent one of the many mechanisms of immunosuppression exploited by HIV.

Challenges of cardiovascular risk assessment in the routine rheumatology outpatient setting: an observational study of 110 rheumatoid arthritis patients.

OBJECTIVE: An annual assessment of cardiovascular (CV) risk factors in rheumatoid arthritis (RA) is recommended, but its practical modalities have not been determined. The objective was to assess the feasibility and usefulness of a standardized CV risk assessment in RA, performed by rheumatologists during outpatient clinics. METHODS: We used a cross-sectional design within a network of rheumatologists. Each rheumatologist included 5 consecutive unselected patients with definite RA. Data collection included standardized assessment of CV risk factors: blood pressure, interpretation of glycemia and of lipid levels, and calculation of the Framingham CV risk score. Outcome criteria included feasibility (missing data and time taken to assess the patients) and usefulness (the CV risk assessment was considered useful if at least 1 modifiable and previously unknown CV risk factor was evidenced). RESULTS: Twenty-two rheumatologists (77% in office-based practice) assessed 110 RA patients. The mean ± SD age was 57 ± 10 years, and the mean ± SD RA duration was 11 ± 9 years; 50 patients (45%) were treated with biologic agents, and 76% were women. Regarding feasibility, missing data were most frequent for glycemia (27% of patients) and cholesterolemia (14% of patients). The mean ± SD duration of the CV risk assessment was 15 ± 5 minutes. The CV risk assessment was considered useful in 33 patients (30%), evidencing dyslipidemia (15% of patients) or high blood pressure (9% of patients) as the most frequently previously unknown CV risk factor. CONCLUSION: The assessment of CV risk factors is feasible, but labor intensive, during an outpatient rheumatology clinic. This assessment identified modifiable CV risk factors in 30% of the patients. These results suggest that RA patients are not sufficiently assessed and treated for CV risk factors.

Prevalence and molecular characterization of Anaplasmataceae agents in free-ranging Brazilian marsh deer (Blastocerus dichotomus).

Anaplasmataceae organisms comprise a group of obligate intracellular gram-negative, tick-borne bacteria that can infect both animals and humans. In the present work we investigate the presence of Ehrlichia, Anaplasma, and Neorickettsia species in blood samples from Brazilian marsh deer (Blastocerus dichotomus), using both molecular and serologic techniques. Blood was collected from 143 deer captured along floodplains of the Paraná River, near the Porto Primavera hydroelectric power plant. Before and after flooding, marsh deer were captured for a wide range research program under the financial support of São Paulo State Energy Company (CESP), between 1998 and 2001. Samples were divided into four groups according to time and location of capture and named MS01 (n=99), MS02 (n=18) (Mato Grosso do Sul, before and after flooding, respectively), PX (n=9; Peixe River, after flooding), and AGUA (n=17; Aguapeí River, after flooding). The seroprevalences for Ehrlichia chaffeensis and Anaplasma phagocytophilum were 76.76% and 20.2% in MS01, 88.88% and 5.55% in MS02, 88.88% and 22.22% in PX, and 94.12% and 5.88% in AGUA, respectively. Sixty-one animals (42.65% of the total population) were PCR-positive for E. chaffeensis PCR (100.0% identity based on 16S rRNA, dsb, and groESL genes). Seventy deer (48.95% of the total population) were PCR-positive for Anaplasma spp. (99.0% of identity with A. platys, and in the same clade as A. phagocytophilum, A. bovis, and A. platys based on 16S rRNA phylogenetic analysis). Our results demonstrate that Brazilian marsh deer are exposed to E. chaffeensis and Anaplasma spp. and may act as reservoirs for these rickettsial agents, playing a role in disease transmission to humans and other animals.

HIPK2 phosphorylates ΔNp63α and promotes its degradation in response to DNA damage.

Homeodomain-interacting protein kinase 2 (HIPK2) is an emerging player in cell response to genotoxic agents that senses damage intensity and contributes to the cell's choice between cell cycle arrest and apoptosis. Phosphorylation of p53 at S46, an apoptosis-specific p53 posttranslational modification, is the most characterized HIPK2 function in response to lethal doses of ultraviolet (UV), ionizing radiation or different anticancer drugs, such as cisplatin, roscovitine and doxorubicin (DOX). Indeed, like p53, HIPK2 has been shown to contribute to the effectiveness of these treatments. Interestingly, p53-independent mechanisms of HIPK2-induced apoptosis were described for UV and tumor growth factor-ß treatments; however, it is unknown whether these mechanisms are relevant for the responses to anticancer drugs. Because of the importance of the so-called 'p53-independent apoptosis and drug response' in human cancer chemotherapy, we asked whether p53-independent factor(s) might be involved in HIPK2-mediated chemosensitivity. Here, we show that HIPK2 depletion by RNA interference induces resistance to different anticancer drugs even in p53-null cells, suggesting the involvement of HIPK2 targets other than p53 in response to chemotherapy. In particular, we found that HIPK2 phosphorylates and promotes proteasomal degradation of ΔNp63α, a prosurvival ΔN isoform of the p53 family member, p63. Indeed, effective cell response to different genotoxic agents was shown to require phosphorylation-induced proteasomal degradation of ΔNp63α. In DOX-treated cells, we show that HIPK2 depletion interferes with ΔNp63α degradation, and expression of a HIPK2-resistant ΔNp63α-Δ390 mutant induces chemoresistance. We identify T397 as the ΔNp63α residue phosphorylated by HIPK2, and show that the non-phosphorylatable ΔNp63α-T397A mutant is not degraded in the face of either HIPK2 overexpression or DOX treatment. These results indicate ΔNp63α as a novel target of HIPK2 in response to genotoxic drugs.

Zoledronic acid enhances Vδ2 T-lymphocyte antitumor response to human glioma cell lines.

Glioblastoma multiforme (GBM), the most frequent and aggressive primary brain tumor in humans, responds modestly to treatment: most patients survive less than one year after diagnosis, despite both classical and innovative treatment approaches. A recent paper focused on γδ T-cell response in GBM patients, suggesting the application of an immunomodulating strategy based on γδ T-cells which is already in clinical trials for other tumors. Human Vγ2 T-cells recognize changes in the mevalonate metabolic pathway of transformed cells by activating cytotoxic response, and by cytokine and chemokine release. Interestingly, this activation may also be induced in vivo by drugs, such as zoledronic acid, that induce the accumulation of Vγ2 T-cell ligand Isopentenyl-pyrophosphate by blocking the farnesyl pyrophosphate synthase enzyme. The aim of our work is to confirm whether bisphosphonate treatment would make glioma cell lines more susceptible to lysis by in vitro expanded γδ T-cells, improving their antitumor activity. We expanded in vitro human Vγ2 T-cells by phosphoantigen stimulation and tested their activity against glioma cell lines. Co-culture with glioma cells induced Vγ2 T-cell differentiation in effector/memory cells, killing glioma cells by the release of perforin. Interestingly, glioma cells were directly affected by zoledronic acid; moreover, treatment increased their activating ability on Vγ2 T-cells, inducing an effective antitumor cytotoxic response. Taken together, our results show that aminobisphosphonate drugs may play a dual role against GBM, by directly affecting tumor cells, and by enhancing the antitumor response of Vγ2 T-cells. Our results confirm the practicability of this approach as a new immunotherapeutic strategy for GBM treatment.

Transrectal real-time elastography of the prostate: Normal patterns.

INTRODUCTION: Given the growing importance in clinical practice of transrectal real-time sonoelastography of the prostate, it is important to define normal patterns correlated to volume growth and reconsider the technical problems. MATERIALS AND METHODS: We selected a sample of 100 men aged 30 to 87 with prostate volumes ranging from 20 to 100 cc. Strain images were obtained using an end-fire convex probe. The elasticity patterns of the various anatomical zones of the prostate were compared with the volume. RESULTS: The peripheral zone showed intermediate elasticity in 100% of cases regardless of the volume. We found some rare small areas of more limited elasticity in 23% of cases, among patients over 40. The posterior side of the central zone exhibited intermediate elasticity, and relative inelasticity was observed on the lateral side and at the base in 79% of cases. The entire central zone appeared compliant in 15% of cases and inelastic in 6%. The transition zone findings were stratified according to gland volume. When the volume was less than 45 cc, the transition zone was elastic in 67% of cases, inhomogeneously inelastic in 22%, and uniformly inelastic in 11%. In glands larger than 45 cc, the appearance was mainly elastic in 31% of cases, inhomogeneously inelastic in 57%, and uniformly inelastic in 12%. CONCLUSIONS: Real-time elastography can distinguish the elastic properties of the prostate and define the normal patterns associated with increases in gland volume.

Regulation of MDM4 (MDMX) function by p76(MDM2): a new facet in the control of p53 activity.

Under basal growth conditions, p53 function is tightly controlled by the members of MDM family, MDM2 and MDM4. The Mdm2 gene codes, in addition to the full-length p90(MDM2), for a short protein, p76(MDM2) that lacks the p53-binding domain. Despite this property and at variance with p90(MDM2), this protein acts positively toward p53, although the molecular mechanism remains elusive. Here, we report that p76(MDM2) antagonizes MDM4 inhibitory function. We show that p76(MDM2) possesses intrinsic ubiquitinating and degrading activity, and through these activities controls MDM4 levels. Furthermore, the presence of p76(MDM2) decreases the association of MDM4 with p53 and p90(MDM2), and antagonizes p53 degradation by the heterodimer MDM4/p90(MDM2). The p76(MDM2)-mediated regulation of MDM4 occurs in the cytoplasm, under basal growth conditions. Conversely, upon DNA damage, phosphorylation of MDM4Ser403 dissociates p76(MDM2) and prevents MDM4 degradation. The overall negative control of MDM4 by p76(MDM2) reflects on p53 function as p76(MDM2) impairs MDM4-mediated inhibition of p53 activity. In agreement with the positive role of p76(MDM2) toward p53, the p76(MDM2)/p90(MDM2) ratio significantly decreases in a group of thyroid tumor samples compared with normal counterparts. Overall, these findings reveal a new mechanism in the control of p53 basal activity that may account for the distinct sensitivity of tissues to stress signals depending on the balance among MDM proteins. Moreover, these data suggest an oncosuppressive function for a product of the Mdm2 gene.

A restricted signature of miRNAs distinguishes APL blasts from normal promyelocytes.

MicroRNAs (miRNAs) are small non-coding RNAs involved in the regulation of critical cell processes such as apoptosis, cell proliferation and differentiation. A small set of miRNAs is differentially expressed in hematopoietic cells and seemingly has an important role in granulopoiesis and lineage differentiation. In this study, we analysed, using a quantitative real-time PCR approach, the expression of 12 granulocytic differentiation signature miRNAs in a cohort of acute promyelocytic leukemia (APL) patients. We found nine miRNAs overexpressed and three miRNAs (miR-107, -342 and let-7c) downregulated in APL blasts as compared with normal promyelocytes differentiated in vitro from CD34+ progenitors. Patients successfully treated with all-trans-retinoic acid (ATRA) and chemotherapy showed downregulation of miR-181b and upregulation of miR-15b, -16, -107, -223, -342 and let-7c. We further investigated whether the APL-associated oncogene, promyelocytic leukemia gene (PML)/retinoic acid receptor alpha (RARalpha), might be involved in the transcriptional repression of miR-107, -342 and let-7c. We found that PML/RARalpha binds the regulatory sequences of the intragenic miR-342 and let-7c. In addition, we observed, in response to ATRA, the release of PML/RARalpha paralleled by their transcriptional activation, together with their host genes, EVL and C21orf34alpha. In conclusion, we show that a small subset of miRNAs is differentially expressed in APL and modulated by ATRA-based treatment.

Risk of tuberculosis is higher with anti-tumor necrosis factor monoclonal antibody therapy than with soluble tumor necrosis factor receptor therapy: The three-year prospective French Research Axed on Tolerance of Biotherapies registry.

OBJECTIVE: Tuberculosis (TB) is associated with anti-tumor necrosis factor (anti-TNF) monoclonal antibody (mAb) therapy, but whether this association is drug-specific remains a concern. Our objective was to describe cases of TB associated with anti-TNF mAb therapy, identify risk factors, and estimate the incidence. METHODS: We conducted an incidence study and a case-control analysis to investigate the risk of newly diagnosed TB associated with the use of anti-TNF agents. As part of the French Research Axed on Tolerance of Biotherapies (RATIO) registry, for 3 years we collected cases of TB among French patients receiving anti-TNF mAb therapy for any indication; for each case, 2 patients treated with anti-TNF agents served as control subjects. RESULTS: We collected 69 cases of TB in patients treated for rheumatoid arthritis (n = 40), spondylarthritides (n = 18), inflammatory colitis (n = 9), psoriasis (n = 1) and Behçet's disease (n = 1) with infliximab (n = 36), adalimumab (n = 28), and etanercept (n = 5). None of the patients had received correct chemoprophylactic treatment. The sex- and age-adjusted incidence rate of TB was 116.7 per 100,000 patient-years. The standardized incidence ratio (SIR) was 12.2 (95% confidence interval [95% CI] 9.7-15.5) and was higher for therapy with infliximab and adalimumab than for therapy with etanercept (SIR 18.6 [95% CI 13.4-25.8] and SIR 29.3 [95% CI 20.3-42.4] versus SIR 1.8 [95% CI 0.7-4.3], respectively). In the case-control analysis, exposure to infliximab or adalimumab versus etanercept was an independent risk factor for TB (odds ratio [OR] 13.3 [95% CI 2.6-69.0] and OR 17.1 [95% CI 3.6-80.6], respectively). Other risk factors were age, the first year of anti-TNF mAb treatment, and being born in an endemic area. CONCLUSION: The risk of TB is higher for patients receiving anti-TNF mAb therapy than for those receiving soluble TNF receptor therapy. The increased risk with early anti-TNF treatment and the absence of correct chemoprophylactic treatment favor the reactivation of latent TB.

HIPK2 is involved in cell proliferation and its suppression promotes growth arrest independently of DNA damage.

INTRODUCTION/OBJECTIVES: The serine/threonine kinase homeodomain-interacting protein kinase 2 (HIPK2) is a co-regulator of an increasing number of transcription factors and cofactors involved in DNA damage response and development. We and others have cloned HIPK2 as an interactor of the p53 oncosuppressor, and have studied the role of this interaction in cell response to stress. Nevertheless, our original cloning of HIPK2 as a p53-binding protein, was aimed at discovering partners of p53 involved in cell differentiation and development, still controversial p53 functions. To this aim, we used p53 as bait in yeast two-hybrid screening of a cDNA library from mouse embryo (day 11 postcoitus) when p53 is highly expressed. METHODS AND RESULTS: In this study, we directly explored whether HIPK2 and p53 cooperate in cell differentiation. By measuring HIPK2 expression and activity in skeletal muscle and haemopoietic differentiation, we observed inverse behaviour of HIPK2 and p53--excluding cooperation activity of these two factors in this event. However, by HIPK2 depletion experiments, we showed that drastic HIPK2 suppression promotes cell-cycle arrest by induction of the cyclin-dependent kinase inhibitor p21(Waf-1/Cip-1). HIPK2 activity is independent of DNA damage and takes place in cell-cycle-arresting conditions, such as terminal differentiation, growth factor deprivation, and G(0) resting. CONCLUSIONS: HIPK2 was found to be involved in cell-cycle regulation dependent on p21(Waf-1/Cip-1) and independent of DNA damage.

SPEAR indicates pesticide effects in streams--comparative use of species- and family-level biomonitoring data.

To detect effects of pesticides on non-target freshwater organisms the Species at risk (SPEAR(pesticides)) bioindicator based on biological traits was previously developed and successfully validated over different biogeographical regions of Europe using species-level data on stream invertebrates. Since many freshwater biomonitoring programmes have family-level taxonomic resolution we tested the applicability of SPEAR(pesticides) with family-level biomonitoring data to indicate pesticide effects in streams (i.e. insecticide toxicity of pesticides). The study showed that the explanatory power of the family-level SPEAR(fm)(pesticides) is not significantly lower than the species-level index. The results suggest that the family-level SPEAR(fm)(pesticides) is a sensitive, cost-effective, and potentially European-wide bioindicator of pesticide contamination in flowing waters. Class boundaries for SPEAR(pesticides) according to EU Water Framework Directive are defined to contribute to the assessment of ecological status of water bodies.

Activation of interferon response genes and of plasmacytoid dendritic cells in HIV-1 positive subjects with GB virus C co-infection.

GB virus C (GBV-C) coinfection has a protective role in Human Immunodeficiency Virus (HIV) infection, and increases the duration of suppression of HIV-1 viremia in patients under Highly Active Anti-Retroviral Therapy (HAART). Since innate antiviral response may be involved in the protection, we analyzed the possible role of GBV-C as activator of innate immunity. To this aim, we measured the extent of activation of the interferon (IFN) system and of circulating Dendritic Cells (DC) in vivo, and the ability of GBV-C to activate these functions in vitro. Activation of IFN system and of circulating DC was compared in GBV-positive and -negative HIV-1 co-infected patients with HAART-driven suppression of HIV-1 viremia. Endogenous levels of IFN-gamma and RNA-dependent protein kinase (PKR) mRNA were significantly higher in peripheral blood mononuclear cells (PBMC) from GBV-C-positive when compared to GBV-C-negative patients. IFN-gamma expression was correlated with all the Interferon response genes (IRGs) and with GBV-C viremia. The frequency of circulating plasmacytoid DC (pDC) expressing the CD80 activation marker was increased in GBV-C-positive patients, and was correlated with GBV-C viral load. In vitro experiments indicated that GBV-C is able to induce IFN-gamma expression in PBMC. In addition, in PBMC cultures GBV-C induced an increase of CD80 expression by pDC, that was reduced by antibody to IFN-gamma. Our data indicate that in HIV-positive patients GBV-C coinfection promotes the activation of IFN-gamma and downstream IRG expression, as well as with the activation/maturation of circulating pDC. GBV-C-driven IFN-gamma activation is, at least in part, responsible for the increased maturation of pDC. This crosstalk may suggest a role for GBV-C coinfection in boosting the innate antiviral response to HIV infection.

An IL-15 dependent CD8 T cell response to selected HIV epitopes is related to viral control in early-treated HIV-infected subjects.

In some early-treated HIV-positive patients, Structured Treatment Interruption (STI) is associated to spontaneous control of viral rebound. Thus, in this clinical setting, we analyzed the immunological parameters associated to viral control. Two groups of early treated patients who underwent STI were retrospectively defined, according to the ability to spontaneously control HIV replication (Controller and Non-controller). Plasma cytokine levels were analyzed by multiplex analysis. CD8 T cell differentiation was determined by polychromatic flow cytometry. Antigen-specific IFN-gamma production was analyzed by ELISpot and intracellular staining after stimulation with HIV-peptides. Long-term Elispot assays were performed in the presence or absence of IL-15. Plasma IL-15 was found decreased over a period of time in Non-Controller patients, whereas a restricted response to Gag (aa.167-202 and 265-279) and Nef (aa.86-100 and 111-138) immunodominant epitopes was more frequently observed in Controller patients. Interestingly, in two Non-Controller patients the CD8-mediated T cells response to immunodominant epitopes could be restored in vitro by IL-15, suggesting a major role of cytokine homeostasis on the generation of protective immunity. In early-treated HIV+ patients undergoing STI, HIV replication control was associated to CD8 T cell maturation and sustained IL-15 levels, leading to HIV-specific CD8 T cell responses against selected Gag and Nef epitopes.