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Multiple sclerosis (MS) is a neurodegenerative inflammatory condition mediated by autoreactive immune processes. Due to its potential to influence host immunity and gut-brain communication, the gut microbiota has been suggested to be involved in the onset and progression of MS. To date, there is no definitive cure for MS, and rehabilitation programs are of the utmost importance, especially in the later stages. However, only a few people generally participate due to poor support, knowledge, and motivation, and no information is available on gut microbiota changes. Herein we evaluated the potential of a brief high-impact multidimensional rehabilitation program (B-HIPE) in a leisure environment to affect the gut microbiota, mitigate MS symptoms and improve quality of life. B-HIPE resulted in modulation of the MS-typical dysbiosis, with reduced levels of pathobionts and the replenishment of beneficial short-chain fatty acid producers. This partial recovery of a eubiotic profile could help counteract the inflammatory tone typically observed in MS, as supported by reduced circulating lipopolysaccharide levels and decreased populations of pro-inflammatory lymphocytes. Improved physical performance and fatigue relief were also found. Our findings pave the way for integrating clinical practice with holistic approaches to mitigate MS symptoms and improve patients’ quality of life.

[Background] High-grade sarcomas are a heterogeneous group of aggressive tumors arising in bone and soft tissues. After relapse, treatment options are limited. The multi-targeted receptor tyrosine kinase inhibitors (TKIs) sunitinib and inhibitor of PD-1 (anti-PD-1) nivolumab have shown antitumor activity in selected subtypes. In this study, we examine the role of TKIs and PD-1 based therapy in in vitro cocultures of sarcoma., [Methods] The human osteosarcoma (SaOS-2) and synovial sarcoma (SYO-1) cell lines were treated with sunitinib. After cell death and proliferation assessment, expression of PD-L1 was analyzed by flow cytometry. Sunitinib-treated sarcoma cells were cocultured with dendritic cells (DCs), and the phenotype of mature DCs was determined by flow cytometry. Mature DCs were cultured with autologous T cells. PD-1 expression on T cells, their proliferation, T regulatory cell (Tregs) induction and IFN-γ production, before and after nivolumab exposure, were analyzed., [Results] Along with its anti-proliferative and direct pro-apoptotic effect on sarcoma cell lines, sunitinib prompted PD-L1 upregulation on sarcoma cells. Interestingly, sunitinib-treated sarcoma cells drive DCs to full maturation and increase their capacity to induce sarcoma-reactive T cells to produce IFN-γ. Conversely, no effect on T cell proliferation and T cell subpopulation composition was observed. Moreover, both bone and synovial sarcoma cell lines induced Tregs through DCs but sunitinib treatment completely abrogated Treg induction. Finally, sarcoma cell lines induced PD-1 upregulation on both effector T cells and Tregs when loaded into DCs, providing a rationale for using PD-1 blockade. Indeed, PD-1 blockade by nivolumab synergized with sunitinib in inducing IFN-γ-producing effector T cells., [Conclusions] Taken together, our in vitro data indicate that the treatment of sarcoma cells with sunitinib can exert significant changes on immune cell subsets toward immune activation, leading to DC-based cross-priming of IFN-γ-producing effector T cells and reduced Treg induction. PD-1 blockade with nivolumab has a synergistic effect with sunitinib, supporting the use of TKI and anti-PD-1 approach in sarcomas, and perhaps in other cancers. DC-targeted drugs, including toll-like receptor 3 inhibitors and CD47 inhibitors, are under development and our preclinical model might help to better design their clinical application., This study was supported by the Associazione Onlus ‘il Pensatore: Matteo Amitrano’, by Bologna AIL (Associazione Italiana contro le Leucemie), Section of Bologna; FATRO, Foundation Corrado and Bruno Maria Zaini-Bologna.

To understand how a protective immune response against SARS-CoV-2 develops over time, we integrated phenotypic, transcriptional and repertoire analyses on PBMCs from mild and severe COVID-19 patients during and after infection, and compared them to healthy donors (HD). A type I IFN-response signature marked all the immune populations from severe patients during the infection. Humoral immunity was dominated by IgG production primarily against the RBD and N proteins, with neutralizing antibody titers increasing post infection and with disease severity. Memory B cells, including an atypical FCRL5+ T-BET+ memory subset, increased during the infection, especially in patients with mild disease. A significant reduction of effector memory, CD8+T cells frequency characterized patients with severe disease. Despite such impairment, we observed robust clonal expansion of CD8+T lymphocytes, while CD4+T cells were less expanded and skewed toward TCMand TH2-like phenotypes. MAIT cells were also expanded, but only in patients with mild disease. Terminally differentiated CD8+GZMB+effector cells were clonally expanded both during the infection and post-infection, while CD8+GZMK+lymphocytes were more expanded post-infection and represented bona fide memory precursor effector cells. TCR repertoire analysis revealed that only highly proliferating T cell clonotypes, which included SARS-CoV-2-specific cells, were maintained post-infection and shared between the CD8+GZMB+and GZMK+subsets. Overall, this study describes the development of immunity against SARS-CoV-2 and identifies an effector CD8+T cell population with memory precursor-like features.

Background Human Immunodeficiency Virus (HIV) infection is a risk factor for tuberculosis (TB). Antiretroviral therapy (ART) changed HIV clinical management but it is still unclear how pre-existing HIV/Mycobacterium tuberculosis (Mtb)-specific CD4+ and CD8+ T-cells are restored. Aim to evaluate the impact of ART and TB therapies on the functional and phenotypic profile of Mtb-specific antigen-response of CD4+ and CD8+ T-cells in prospectively enrolled HIV-TB co-infected patients. Methods ART-naive HIV-infected patients, with or without active TB or latent TB infection (LTBI), were enrolled before and after starting ART and TB therapies. Peripheral blood mononuclear cells (PBMC) were stimulated overnight with Mtb and HIV antigens (GAG). Cytokine expression and phenotype profile were evaluated by flow cytometry. Cytomegalovirus (CMV) and staphylococcal enterotoxin B (SEB) were also used. Results The median of absolute number of CD4+ T-cells increased after ART and TB therapies in all groups analyzed, while the median of absolute number of CD8+ T-cells decreases in HIV and HIV-LTBI groups. Treatments significantly increased the frequency of Mtb-specific CD4+ T-cells in the HIV-LTBI (p = 0.015) with a rise of the central memory compartment. The magnitude of the CD4+ T-cell response to HIV-GAG significantly increased in active TB (p = 0.03), whereas the magnitude of CMV-specific CD4+ T-cell response decreased in all the groups. Similarly, the treatments increased the number of Mtb-specific CD8+ responders in both HIV-LTBI and HIV-TB groups, whereas the phenotype distribution was dependent on the antigens used and on the stage of infection/disease. Conclusions After therapies the median of absolute number and the proportion of CD4+ T-cells increased in all groups whereas the median of absolute count and proportion of CD8+ T-cells decreased in the HIV and HIV-LTBI subjects. Interestingly, an increased frequency of CD4+ T-cell response to RD1 proteins in HIV-LTBI subjects was found. These results contribute to a better understanding of the effect of ART and TB therapies on the modulation of Mtb-specific CD4+ and CD8+ T-cells subsets.

目的 探讨脑源性神经营养因子（BDNF）增强间充质干细胞（MSC）抑制滤泡辅助性T细胞（Tfh细胞）的作用及机制。 方法 ELISA法检测MSC培养上清中吲哚胺2,3-二加氧酶（IDO）、IL-10、TGF-β和IL-21的含量；采集健康志愿者的外周血标本，采用人淋巴细胞分离液分离外周血中的淋巴细胞；采用Transwell小室进行MSC和淋巴细胞共培养，流式细胞术检测CD4+CXCR5+ Tfh细胞及其亚群的比例。 结果 ①BDNF组（BDNF刺激的MSC）培养上清IL-10、TGF-β、IDO浓度均高于对照组（加入等体积磷酸盐缓冲液）[IL-10：（42.1±4.4）ng/ml对（19.3±2.1）ng/ml，t=4.761，P=0.009；TGF-β：（13.9±1.7）ng/ml对（5.3±0.6）ng/ml，t=5.129，P=0.008；IDO：（441.3±56.9）ng/ml对（226.7±37.6）ng/ml，t=3.130，P=0.035]；②BDNF组（淋巴细胞与BDNF刺激的MSC共培养）与MSC组（淋巴细胞与MSC共培养）比较：CD4+CXCR5+Tfh细胞比例降低[（3.37±0.21）%对（6.51±0.27）%，t=9.353，P

Innate lymphoid cells (ILCs) are the latest identified innate immune cell family. Given their similarity in transcription factor expression and cytokine secretion profiles, ILCs have been considered as the innate phenocopy of CD4 Th cells. Here, we explored the transcriptome of circulating human ILC subsets as opposed to CD4 Th cell subsets. We describe transcriptomic differences between total ILCs and total CD4 Th cells, as well as between paired innate and adaptive cell subsets (ILC1 vs. Th1; ILC2 vs. Th2; and ILC3 vs. Th17 cells). In particular, we observed differences in expression of genes involved in cell trafficking such as CCR1, CCR6 and CXCR3, innate activation and inhibitory functions, including CD119, 2B4, TIGIT, and CTLA‐4, and neuropeptide receptors, such as VIPR2. Moreover, we report for the first time on distinct expression of long noncoding RNAs (lncRNAs) in innate vs. adaptive cells, arguing for a potential role of lncRNA in shaping human ILC biology. Altogether, our results point for unique, rather than redundant gene organization in ILCs compared to CD4 Th cells, in regard to kinetics, fine‐tuning and spatial organization of the immune response., Human ILCs and CD4 Th cells show shared, but also distinct transcriptomic profiles, including in lncRNAs, supporting their distinct temporal and spatial activation during immune responses.

In their recent paper, Weili Xu et al. [1] described the different behaviors of Vδ1pos and Vδ2pos T cell subsets in response to lifelong stress and claimed that Vδ2pos T cells are not affected by aging and Human Cytomegalovirus (HCMV) infection. While we agree that these two γδ T cell subsets diverge both in phenotype/function and in tissue distribution, we are somewhat surprised that authors did not take into account the several previously published and contradictory experimental evidence in regards to senescence of Vδ2pos T cells [2,3]. These latter studies reported that HCMV infection not only induces a clonal expansion of a distinct Vγ9neg/Vδ2pos T cell subset, but also determines a concomitant adaptive differentiation from CD27high naïve cells to CD27low/neg terminal-effectors. However, Weili Xu et al. argued that the expression and kinetics of both CD27 and CD45RA surface markers do not change and follow the homeostatic changes of Vδ2pos T cells. This statement goes in the opposite direction to previously reported findings as the CD27/CD45RA phenotype has been shown to mark the maturation and differentiation (TNaïve, TCentral-Memory, Teffector-Memory and TEffectory-Memory RA) of Vδ2pos T cells. Indeed, the different surface expression of both CD27 and CD45 parallel the progressive decrease of telomere length, the proliferative capacity as well as the different effector-functions and resistance to death of Vδ2+ T cells in response to antigens and homeostatic cytokines [4,5]. Hence, we believe that these controversial issues require further discussion beyond the unilateral conclusion given by the study of Weili Xu et al.

Hepatitis B virus (HBV) is a noncytopathic, hepatotropic, double-stranded DNA virus that causes acute and chronic hepatitis. Although HBV does not induce a measurable innate immune response in the infected liver, the outcome of infection is determined by the kinetics, breadth, vigor, trafficking, and effector functions of HBV-specific adaptive T cell responses, and the development of neutralizing antibodies. Dysregulation of one or more of these events leads to persistent HBV infection and a variably severe chronic necroinflammatory liver disease that fosters the development of hepatocellular carcinoma. Deeper understanding of the mechanisms responsible for immunological tolerance to HBV is needed in order to devise immunotherapeutic strategies to cure chronic HBV infection and prevent its life-threatening sequellae.

During the last few years, the gut microbiota has gained increasing attention as a consequence of its emerging role as a modulator of the immune system. With the advent of the era of checkpoint inhibitors immunotherapy and adoptive cell transfer (ACT) in oncology, these findings became of primary relevance in light of experimental data that suggested the microbiota involvement as a plausible predictor of a good or poor response. These remarks justify the efforts to pinpoint the specific actions of the microbiota and to identify new strategies to favorably edit its composition.

Prevention of graft-versus-host disease (GVHD) is paramount for allogeneic hematopoietic stem cell transplantation (HSCT) to treat nonmalignant diseases. We previously reported that allogeneic HSCT for severe aplastic anemia (SAA) using the fludarabine, cyclophosphamide, and alemtuzumab (Campath-1H) (FCC) regimen is associated with a very low risk of GVHD and excellent clinical outcomes. We now report a single-center study of 45 patients with longer follow-up and investigation of lymphocyte recovery. Overall survival (OS) was 93%, and event-free survival (EFS) was 90.7%. Acute and chronic GVHD each occurred in 6 patients (13.3%), and only 1 case was severe. Mixed T cell chimerism was frequent and persisted after cessation of immunosuppression. T cells were extensively depleted, representing only 11.3% of lymphocytes at day 30 and rising to 43.8% by 1 year, but still significantly below normal levels (67.2%; P = .018), and deficiency persisted after immunosuppressive therapy (IST) withdrawal. Depletion of CD4 T cells was particularly profound, causing inversion of the normal CD4:CD8 T cell ratio. T cell subset composition was also abnormal, with memory and effector T cells predominating for at least 6 months after FCC HSCT. Analysis of T cell subset chimerism showed that CD4 T cells were predominantly donor-derived at 1 year, whereas recipient-derived CD8 T cells shaped mixed chimerism with a notable contribution of recipient effector CD8 T cells. The prolonged mixed T cell chimerism after IST withdrawal and low incidence of GVHD indicates the establishment of mutual tolerance, but the low incidence of viral disease suggests maintenance of antiviral immunity. Our study shows that despite the abnormal T cell profile after allogeneic HSCT for SAA using the FCC regimen, this regimen is conducive to an excellent clinical outcome.

Upon T cell receptor stimulation, CD4(+) T helper (Th) lymphocytes release extracellular vesicles (EVs) containing microRNAs. However, no data are available on whether human CD4(+) T cell subsets release EVs containing different pattern of microRNAs. The present work aimed at filling this gap by assessing the microRNA content in EVs released upon in vitro T cell receptor stimulation of Th1, Th17, and T regulatory (Treg) cells. Our results indicate that EVs released by Treg cells are significantly different compared with those released by the other subsets. In particular, miR-146a-5p, miR-150-5p, and miR-21-5p are enriched, whereas miR-106a-5p, miR-155-5p, and miR-19a-3p are depleted in Treg-derived EVs. The in vitro identified EV-associated microRNA signature was increased in serum of autoimmune patients with psoriasis and returned to healthy levels upon effective treatment with etanercept, a biological drug targeting the TNF pathway and suppressing inflammation. Moreover, Gene Set Enrichment Analysis showed an over-representation of genes relevant for T cell activation, such as CD40L, IRAK1, IRAK2, STAT1, and c-Myb in the list of validated targets of Treg-derived EV miRNAs. At functional level, Treg-derived (but not Th1/Th17-derived) EVs inhibited CD4(+) T cell proliferation and suppressed two relevant targets of miR-146a-5p: STAT1 and IRAK2. In conclusion, our work identified the miRNAs specifically released by different human CD4(+) T cell subsets and started to unveil the potential use of their quantity in human serum to mark the pathological elicitation of these cells in vivo and their biological effect in cell to cell communication during the adaptive immune response.

Purpose The aim of our study was to prospectively evaluate the distribution of gamma-delta (γδ)1 and γδ2 T cells and their phenotypes in peripheral blood and prostate samples of patients diagnosed with or without prostate cancer (PCa) at prostate biopsy. Materials and methods A consecutive series of 43 outpatients underwent trans-rectal echo-guided prostate biopsy for suspected PCa. Flow cytometry analysis was used to identify and characterize the γδ T cells populations in peripheral blood and tissue samples. Patients were stratified according to the presence or not of PCa, and its International Society of Urological Pathology (ISUP) grade (1 vs. ≥2). Results The distribution of γδ T cells in peripheral blood and prostate tissue showed wide variability and non-significant differences. A slightly higher percentage of δ2 T cells and a slightly lower percentage of δ1 T cells were found in peripheral blood of cancer patients. A non-significantly higher percentage of both Vδ1 and Vδ2 was expressed in cancer tissues, but a trend for lower distribution of δ1 and δ2 T cells was observed in ISUP grade ≥2. The "central memory" and "effector memory" were the most expressed T cells phenotype in peripheral blood and tissue samples. However no substantial differences in T cells subtypes distribution between cancer and healthy tissue were observed. Conclusions No substantially different percentages of γδ T cells were found in peripheral blood and biopsy samples of healthy and PCa patients. However a non-significant trend for lower infiltrate in higher ISUP grade cancer tissue was observed, suggesting a possible role for the immunosurveillance of PCa.

Asthma is a high-prevalence disease, still accounting for mortality and high direct and indirect costs. It is now recognized that, despite the implementation of guidelines, a large proportion of cases remain not controlled. Certainly, adherence to therapy and the education of patients remain the primary objective, but the increasingly detailed knowledge about the pathogenic mechanisms and new biotechnologies offer the opportunity to better address and treat the disease. Interleukin (IL)-13 and IL-4 appear as the most suitable targets to treat the T helper 2 (TH2)-mediated forms (endotypes) of asthma. IL-13 and IL-4 partly share the same receptor and signaling pathways and both are deeply involved in immunoglobulin E (IgE) synthesis, eosinophil activation, mucus secretion and airways remodeling. Several anti-IL-13 strategies have been proposed (anrukinzumab, lebrikizunab and tralokinumab), with relevant clinical results reported with lebrikizumab. Such studies facilitate better definition of the possible predictive markers of response to a specific treatment (e.g. eosinophils, total IgE, fraction of exhaled nitric oxide and periostin). In parallel, anti-IL-4 strategies have been attempted (pascolizumab, pitakinra and dupilumab). So far, dupilumab was reported capable of reducing the severity of asthma and the rate of exacerbations. IL-13 and IL-4 are crucial in TH2-mediated inflammation in asthma, but it remains clear that only specific endotypes respond to these treatments. Although the use of anti-IL-14 and anti-IL-13 strategies is promising, the search for appropriate predictive biomarkers is urgently needed to better apply biological treatments.

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 AŽÂ± 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 AŽÂ±, and exhibit greater resistance to inhibitory signals during chronic HCV infection.

Background: Several studies have been conducted in China in order to investigate the potential predictors of serofast state after treatment among syphilitic patients. However, there is a remarkable diversity among the results. This meta-analysis was conducted to assess potential predictors of serofast among syphilitic patients in China. Methods: International and national electronic databases were searched up to September 2013. Reference lists of retrieved articles were also reviewed. Cohort or case-control studies addressing risk factors of serofast among syphilitic patients were included in this study. Results: We assessed 27 separate studies involving overall 6682 HIV-negative participants with syphilis of which 1962 remained in the serofast state. The serofast was positively associated with older age(Ptrend=0.001), female(summary risk ratio[sRR]=1.50, 95%CI:1.34–;1.68), latent syphilis(sRRlatent vs primary=3.17, 95%CI: 2.66–;3.77; sRRlatent vs secondary=2.00, 95%CI: 1.48–;2.69) as well as non-penicillin treatment(sRR =2.99, 95%CI:2.45–;3.67), but negatively associated with higher baseline titers(sRR>1:32 vs ≤1:32=0.63, 95%CI: 0.54–;0.75). Compared with healthy group and serological cure group, respectively, the levels of CD4 (+), IL-2, and IL-6 among serofast patients were decreased (standardized mean difference[SMD]0, P

The cytokine IL-21 is closely related to IL-2 and IL-15, a cytokine family that uses the common γ-chain for signaling. IL-21 is expressed by activated CD4+ T cells. We examined the role of IL-21 in the autoimmune disease experimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis. IL-21 administration before induction of EAE with a neuroantigen, myelin oligodendrocyte glycoprotein peptide 35-55, and adjuvant enhanced the inflammatory influx into the CNS, as well as the severity of EAE. Autoreactive T cells purified from IL-21-treated mice transferred more severe EAE than did the control encephalitogenic T cells. No such effects were observed when IL-21 was administered after EAE progressed. Additional studies demonstrated that IL-21 given before the induction of EAE boosted NK cell function, including secretion of IFN-γ. Depletion of NK cells abrogated the effect of IL-21. Therefore, IL-21, by affecting NK cells, has differential effects during the initiation and progression of autoimmune responses against neuroantigens.

In the last years, dendritic cells (DC) have been evaluated for antitumor vaccination. Although DC-based vaccines have raised great expectations, their clinical translation has been largely disappointing. For these results, several explanations have been proposed. In particular, the concomitant expression by DCs of tolerogenic pathways, such as the immunosuppressive agent indoleamine 2,3-dioxygenase-1 (IDO1), has been demonstrated. The aim of this study is to evaluate both the stimulatory and the tolerogenic feature of monocyte-derived DCs (Mo-DCs) after maturation with PGE2. In particular, the role of IDO1 expression in PGE2-matured Mo-DCs has been addressed. Here we show that PGE2, which is required for full maturation of DCs, is one mediator of DC tolerance by enhancing IDO1. PGE2-mediated expression of IDO1 results in the production of kynurenine, in the generation of Tregs, and in the inhibition of either the allogeneic or the autologous antigen-specific stimulatory capacity of DCs. When pulsed with leukemic lysates and matured with PGE2, DCs are impaired in the induction of IFN-γsecreting CD4+and CD8+T cells due to IDO1 upregulation. Moreover, the inhibition of IDO1 enhances the antileukemic response. Overall, these results point toward the use of IDO1 inhibitors to enhance the vaccination capacity of DCs, matured with PGE2.

Objective IL-9 has been shown to be upregulated before the clinical onset of articular disease in RA. The exact role of IL-9 and Th9 cells in RA, however, has not yet been adequately studied. The aim of this study was to evaluate the expression of IL-9 and IL-9-expressing cells in RA patients. Methods IL-9, IL-9R, PU.1, IL-9, thymic stromal lymphopoietin (TSLP), IL-4 and TGF-β expression was assessed by real-time-PCR in the synovial tissues of RA and OA patients. IL-9, IL-9R, IL-4, TSLP and TGF-β were also investigated by immunohistochemistry. Peripheral CD4(+) T cell subsets were studied by flow cytometry analysis before and after incubation with citrullinated peptides. Results IL-9 was overexpressed in RA synovial tissues and correlated with the degree of histological organization of B and T cells in ectopic lymphoid structures. The majority of IL-9-producing cells were identified as CD3(+) cells. Increased mRNA and protein expression of IL-9R, IL-4, TSLP and TGF-β was also observed in RA synovial tissue. Blood peripheral Th9 cells were expanded by citrullinated peptides. Conclusion These results indicate that Th9 cells and IL-9 were frequently detected in peripheral blood mononuclear cells and synovia of RA patients. A possible pathogenic role for Th9 in RA is discussed.

In this issue of the journal, we host a topic focused on the roles of human Forkhead-box (FOX) gene family members, including FOXN1, FOXP genes, and FOXO1, in the immune system. In the first review of the issue, Palamaro et al. focused their attention on the pivotal role of FOXN1 in T-cell development and the clinical implications of its mutation in humans. Dr Fleskens and Dr van Boxtel detailed the role of FOXP members in immune regulation. Concerning the roles of FOXP members in immune response, Vent-Schmidt et al. focused the attention on FOXP3. Passerini et al. highlighted the current knowledge on the involvement of FOXP3 in the development and function of Treg cells. Eventually, in the last review of this special issue, Szydłowski et al. focused on the role of FOXO1 in B-cell development and differentiation, paying particular attention to the role of PI3K-AKT signaling activation in development, differentiation, function, and homeostasis of B cells. Notably, studies on the role of FOX family members in immune response could be helpful to further investigate pathogenesis of immunological disease and to develop a novel therapeutics approach for human diseases.

The interplay of the immune system with other aspects of physiology is one of the hottest topics of the recent literature. A crucial example is the influence of metabolic cues on immune responses. It is now well accepted that upon activation, T lymphocytes take on a metabolic profile profoundly distinct from that of their quiescent and anergic counterparts; in these sense, T cell metabolism is highly dynamic and has a serious impact on the ability of T cell to grow, activate and differentiate. Specific metabolic pathways provide energy and biosynthetic precursors able to support specific T cell functions, such as effector, regulatory and memory. Here, we review the main signaling pathways that control metabolism and how the metabolic phenotypes of T cell subtypes integrate with their specific function. (C) 2013 Elsevier B.V. All rights reserved.

Establishment and maintenance of pregnancy represents a challenge for the maternal immune system since it has to defend against pathogens and tolerate paternal alloantigens expressed in fetal tissues. Regulatory T (Treg) cells, a subset of suppressor CD4(+) T cells, play a dominant role in the maintenance of immunological self-tolerance by preventing immune and autoimmune responses against self-antigens. Although localized mechanisms contribute to fetal evasion from immune attack, in the last few years it has been observed that Treg cells are essential in promoting fetal survival avoiding the recognition of paternal semi-allogeneic tissues by maternal immune system. Several functional studies have shown that unexplained infertility, miscarriage and pre-clampsia are often associated with deficit in Treg cell number and function while normal pregnancy selectively stimulates the accumulation of maternal forkhead-box-P3(+) (FoxP3(+)) CD4(+) Treg cells with fetal specificity. Some papers have been reported that the number of Treg cells persists at elevated levels long after delivery developing an immune regulatory memory against father's antigens, moreover these memory Treg cells rapidly proliferate during subsequent pregnancies, however, on the other hand, there are several evidence suggesting a clear decline of Treg cells number after delivery. Different factors such as cytokines, adipokines, pregnancy hormones and seminal fluid have immunoregulatory activity and influence the success of pregnancy by increasing Treg cell number and activity. The development of strategies capable of modulating immune responses toward fetal antigens through Treg cell manipulation, could have an impact on the induction of tolerance against fetal antigens during immune-mediated recurrent abortion.

Celiac disease (CD)-associated inflammation is characterized by high interleukin- 21 (IL-21), but the mechanisms that control IL-21 production are not fully understood. Here we analyzed IL-21 cell sources and examined how IL-21 production is regulated in CD. Intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs), isolated from CD patients and non-CD controls, were analyzed for cell markers, cytokines, and transcription factors by flow cytometry. IL-21 was highly produced by CD4+ and CD4+/CD8+ IELs and LPLs in active CD. IL-21-producing cells coexpressed interferon-γ (IFN-γ) and to a lesser extent T helper type 17 (Th17) cytokines. Treatment of control LPLs with IL-15, a cytokine overproduced in CD, activated Akt and STAT3 (signal transducer and activator of transcription 3), thus enhancing IL-21 synthesis. Active CD biopsies contained elevated levels of Akt, and blockade of IL-15 in those samples reduced IL-21. Similarly, neutralization of IL-15 in biopsies of inactive CD patients inhibited peptic-tryptic digest of gliadin-induced IL-21 expression. These findings indicate that in CD, IL-15 positively regulates IL-21 production.

The mechanisms that induce T cell tolerance to circulating self-proteins are still controversial, and both the deletion and selection of autoreactive T cells have been observed in the thymus of transgenic mouse models. To address the question of the induction of tolerance to circulating self-constituents, a T cell receptor-transgenic mouse specific for the serum protein immunoglobulin (Ig) gamma and (IgG2ab) was generated. The choice of an allotype-specific T cell also allowed the generation of transgenic control mice not expressing the self-antigen. It was found that the transgenic T cells were not deleted in the thymus, did not become tolerant in the periphery, and regulated the function of gamma 2ab-positive B cells as shown by the lack of IgG2ab protein in the serum of the transgenic mice. In spite of this activity in vivo, the transgenic T cells did not proliferate in vitro in response to the allotype-specific peptide. Interestingly, antigen-specific T cell proliferation could be restored if the transgenic mice were previously challenged to induce IgG2ab responses. After this challenge, IgG2ab protein in the serum of the transgenic mice could be partially restored, although still remaining much lower than in control mice. In addition, there was a dramatic increase in serum IgE levels, suggesting that newly generated gamma 2ab-secreting B cells can be induced to switch to IgE in the presence of allotype-specific T cells. These results indicate that Ig-specific T cells may represent a late-acting form of T cell help for the regulation of the IgG2a-to-IgE class switch.

Along with their immunogenic role, dendritic cells (DCs) are also critical in maintaining tolerance to self-antigens by inducing regulatory T cells (Tregs) via the expression of the immunomodulatory enzyme indoleamine 2,3-dioxygenase 1 (IDO1). In turn, Tregs modulate the maturation and/or function of DCs. In immune thrombocytopenia (ITP), the interaction between DCs and Tregs has never been investigated although decreased number/function of Tregs as well as altered DCs have been described. Here, we ask whether, in ITP: (1) IDO1 expression/activity is decreased in mature DCs; (2) IDO1-mediated Treg generation is impaired; and (3) DC maturation is abnormally modulated by Tregs. We found that in ITP, DCs show reduced capability of upregulating the expression/activity of IDO1. This finding results in the reduced ability of mature DCs of converting T cells into Tregs. In turn, Tregs are characterized by decreased interleukin-10 production and show lower ability of inhibiting DC maturation. In conclusion, these data point out the role of IDO1 in the impaired regulatory T cell development of ITP patients and suggest that the cross-talk between Tregs and DCs is hampered and plays a pathogenetic role.

Background & Aims An increased number of macrophages in adipose tissue is associated with insulin resistance and metabolic dysfunction in obese people. However, little is known about other immune cells in adipose tissue from obese people, and whether they contribute to insulin resistance. We investigated the characteristics of T cells in adipose tissue from metabolically abnormal insulin-resistant obese (MAO) subjects, metabolically normal insulin-sensitive obese (MNO) subjects, and lean subjects. Insulin sensitivity was determined by using the hyperinsulinemic euglycemic clamp procedure. Methods We assessed plasma cytokine concentrations and subcutaneous adipose tissue CD4 + T-cell populations in 9 lean, 12 MNO, and 13 MAO subjects. Skeletal muscle and liver samples were collected from 19 additional obese patients undergoing bariatric surgery to determine the presence of selected cytokine receptors. Results Adipose tissue from MAO subjects had 3- to 10-fold increases in numbers of CD4 + T cells that produce interleukin (IL)-22 and IL-17 (a T-helper [Th] 17 and Th22 phenotype) compared with MNO and lean subjects. MAO subjects also had increased plasma concentrations of IL-22 and IL-6. Receptors for IL-17 and IL-22 were expressed in human liver and skeletal muscle samples. IL-17 and IL-22 inhibited uptake of glucose in skeletal muscle isolated from rats and reduced insulin sensitivity in cultured human hepatocytes. Conclusions Adipose tissue from MAO individuals contains increased numbers of Th17 and Th22 cells, which produce cytokines that cause metabolic dysfunction in liver and muscle in vitro. Additional studies are needed to determine whether these alterations in adipose tissue T cells contribute to the pathogenesis of insulin resistance in obese people.

Adaptive type I regulatory T (Tr1) cells are suppressor cells characterized by the production of interleukin (IL)-10 in the absence of IL-4. IL-10 is essential not only for suppression of effector cells by Tr1 cells, but also for their differentiation in vitro and in vivo. However, little is known on the molecular mechanisms underneath the IL-10-mediated induction of Tr1 cells. Human Leukocyte Antigen (HLA)-G, a non-classical HLA class I molecule, has both direct inhibitory effects on natural killer cells, dendritic cells (DC), and T cells and long-term tolerogenic indirect effects by inducing regulatory T (Tr) cells. in the present review, we discuss current findings on Tr-cell induction by the different isoforms of HLA-G, focusing on the relationship among HLA-G, its ligands, and IL-10. We recently described a subset of human DC, termed DC-10, that express high levels of HLA-G and ILT4, secrete high amounts of IL-10, and induce allospecific Tr1 cells in vitro via an IL-10-dependent ILT4/HLA-G pathway. IL-10, HLA-G, and ILT4 may also be involved in Tr1-cell induction in vivo. Overall, these data demonstrate that cross-regulation between IL-10 and HLA-G may be instrumental for Tr1-cell induction and tolerance. (C) 2009 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

Actively induced Lewis rat Experimental Autoimmune Encephalomyelitis (EAE) is a highly reproducible model for portraying the acute phase of multiple sclerosis. Our aim was to get more information about this model by means of flow cytometry looking at potential markers for tracing new treatments' efficacy. Thus we characterized the changes occurring in encephalitogenic TCR Vbeta8.2(+) frequency and the adhesion molecule alpha4 integrin expression in both spleen and spinal cord T cells. The increase in both these parameters was observed only in spinal cord infiltrating T cells while relevant changes in spleen cell composition were observed as early as disease onset.

Immunotherapy may provide valid alternative therapy for patients with hormone-refractory metastatic prostate cancer. However, if the tumor environment exerts a suppressive action on antigen-specific tumor-infiltrating lymphocytes (TIL), immunotherapy will achieve little, if any, success. In this study, we analyzed the modulation of TIL responses by the tumor environment using collagen gel matrix–supported organ cultures of human prostate carcinomas. Our results indicate that human prostatic adenocarcinomas are infiltrated by terminally differentiated cytotoxic T lymphocytes that are, however, in an unresponsive status. We demonstrate the presence of high levels of nitrotyrosines in prostatic TIL, suggesting a local production of peroxynitrites. By inhibiting the activity of arginase and nitric oxide synthase, key enzymes of L-arginine metabolism that are highly expressed in malignant but not in normal prostates, reduced tyrosine nitration and restoration of TIL responsiveness to tumor were achieved. The metabolic control exerted by the tumor on TIL function was confirmed in a transgenic mouse prostate model, which exhibits similarities with human prostate cancer. These results identify a novel and dominant mechanism by which cancers induce immunosuppression in situ and suggest novel strategies for tumor immunotherapy.

Lymphocytes isolated from human immunodeficiency virus (HIV)-infected patients have dysregulated cell-cycle control, consisting of increased activation of the cyclin B1/p34 cdc2 complex and abnormal nucleolar structure. To better characterize the molecular features of the HIV-associated cell-cycle perturbations, we performed a detailed analysis of the posttranslational regulation of nucleolin, a key structural protein in the nucleolus. We found that, in concanavalin A-stimulated lymphocytes from HIV-infected patients, the inappropriate activation of the cyclin B1/p34 cdc2 kinase complex is temporally associated with increased threonine phosphorylation, augmented fragmentation, and prominent extranuclear and cell-surface localization of nucleolin. Importantly, increased lymphocyte apoptosis is observed at the time of cell-surface localization of nucleolin. These results may delineate a direct molecular link between abnormal activation of cyclin B1/p34 cdc2 and the changes in the nucleolar structure, thus providing a better molecular definition of HIV-associated cell-cycle dysregulation.