Search

Acquired immune function shows recognizable changes over time with organismal aging. These changes include T-cell dysfunction, which may underlie diminished resistance to infection and possibly various chronic age-associated diseases in the elderly. T-cell dysfunction may occur at distinct stages, from naive cells to the end stages of differentiation during immune responses. The thymus, which generates naive T cells, shows unusually early involution resulting in progressive reduction of T-cell output after adolescence, but peripheral T-cell numbers are maintained through antigen-independent homeostatic proliferation of naive T cells driven by the major histocompatibility complex associated with self-peptides and homeostatic cytokines, retaining the diverse repertoire. However, extensive homeostatic proliferation may lead to the emergence of dysfunctional CD4+ T cells with features resembling senescent cells, termed senescence-associated T (SA-T) cells, which increase and accumulate with age. In situations such as chronic viral infection, T-cell dysfunction may also develop via persistent antigen stimulation, termed exhaustion, preventing possible immunopathology due to excessive immune responses. Exhausted T cells are developed through the effects of checkpoint receptors such as PD-1 and may be reversed with the receptor blockade. Of note, although defective in their regular T-cell antigen-receptor-mediated proliferation, SA-T cells secrete abundant pro-inflammatory factors such as osteopontin, reminiscent of an SA-secretory phenotype. A series of experiments in mouse models indicated that SA-T cells are involved in systemic autoimmunity as well as chronic tissue inflammation following tissue stresses. In this review, we discuss the physiological aspects of T-cell dysfunction associated with aging and its potential pathological involvement in age-associated diseases and possibly cancer. [ABSTRACT FROM AUTHOR]

Interleukin-17-expressing CD4+ T helper 17 (Th17) cells are considered as critical regulators of multiple sclerosis disease activity. However, depending on the species and pro-inflammatory milieu, Th17 cells are functionally heterogeneous, consisting of subpopulations that differentially produce interleukin-17, interferon-gamma and granulocyte macrophage colony-stimulating factor. In the current study, we studied distinct effector phenotypes of human Th17 cells and their correlation with disease activity in multiple sclerosis patients. T helper memory populations single- and double-positive for C-C chemokine receptor 6 (CCR6) and CXC chemokine receptor 3 (CXCR3) were functionally assessed in blood and/or cerebrospinal fluid from a total of 59 patients with clinically isolated syndrome, 35 untreated patients and 24 natalizumab-treated patients with relapsing-remitting multiple sclerosis, and nine patients with end-stage multiple sclerosis. Within the clinically isolated syndrome group, 23 patients had a second attack within 1 year and 26 patients did not experience subsequent attacks during a follow-up of >5 years. Low frequencies of T helper 1 (Th1)-like Th17 (CCR6+CXCR3+), and not Th17 (CCR6+CXCR3-) effector memory populations in blood strongly associated with a rapid diagnosis of clinically definite multiple sclerosis. In cerebrospinal fluid of clinically isolated syndrome and relapsing-remitting multiple sclerosis patients, Th1-like Th17 effector memory cells were abundant and showed increased production of interferon-gamma and granulocyte macrophage colony-stimulating factor compared to paired CCR6+ and CCR6-CD8+ T cell populations and their blood equivalents after short-term culturing. Their local enrichment was confirmed ex vivo using cerebrospinal fluid and brain single-cell suspensions. Across all pro-inflammatory T helper cells analysed in relapsing-remitting multiple sclerosis blood, Th1-like Th17 subpopulation T helper 17.1 (Th17.1; CCR6+CXCR3+CCR4-) expressed the highest very late antigen-4 levels and selectively accumulated in natalizumab-treated patients who remained free of clinical relapses. This was not found in patients who experienced relapses during natalizumab treatment. The enhanced potential of Th17.1 cells to infiltrate the central nervous system was supported by their predominance in cerebrospinal fluid of early multiple sclerosis patients and their preferential transmigration across human brain endothelial layers. These findings reveal a dominant contribution of Th1-like Th17 subpopulations, in particular Th17.1 cells, to clinical disease activity and provide a strong rationale for more specific and earlier use of T cell-targeted therapy in multiple sclerosis. [ABSTRACT FROM AUTHOR]

The incidence of allergic diseases, which increased to epidemic proportions in developed countries over the last few decades, has been correlated with altered gut microbiota colonization. Although probiotics may play a critical role in the restoration of gut homeostasis, their efficiency in the control of allergy is controversial. Here, we aimed to investigate the effects of probiotic treatment initiated at neonatal or adult ages on the suppression of experimental ovalbumin (OVA)-induced asthma. Neonatal or adult mice were orally treated with probiotic bacteria and subjected to OVAinduced allergy. Asthma-like symptoms, microbiota composition and frequencies of the total CD4+ T lymphocytes and CD4+Foxp3+ regulatory T (Treg) cells were evaluated in both groups. Probiotic administration to neonates, but not to adults, was necessary and sufficient for the absolute prevention of experimental allergen-induced sensitization. The neonatally acquired tolerance, transferrable to probiotic-untreated adult recipients by splenic cells from tolerant donors, was associated with modulation of gut bacterial composition, augmented levels of cecum butyrate and selective accumulation of Treg cells in the airways. Our findings reveal that a cross-talk between a healthy microbiota and qualitative features inherent to neonatal T cells, especially in the Treg cell subset, might support the beneficial effect of perinatal exposure to probiotic bacteria on the development of long-term tolerance to allergens. [ABSTRACT FROM AUTHOR]

It is well-established that CD28 co-stimulation is required for the development and the proliferation of thymus-derived regulatory T cells (tTregs). Meanwhile, the role of CD28 co-stimulation in the homeostasis of peripherally derived Tregs (pTregs) remains unclear. To clarify this issue, we analyzed Tregs in small and large intestines (SI and LI), the principle sites of pTreg development. Interestingly, and different from in the thymus, Tregs were abundant in the intestines of CD28-/- mice, and most of them were phenotypically pTregs. We showed that CD28-/- naive T cells differentiated into pTregs in the LI after oral exposure to antigens and that CD28-/- pTregs in the LI had the same highly proliferative activity as CD28+/- cells. CD28-/- pTregs acquired these Treg-specific features at transcriptional and epigenetics levels. On the other hand, some immune suppressive molecules were down-regulated in CD28-/- pTregs. Correspondingly, the suppressive activity of CD28-/- pTregs was weaker than CD28+/+ cells. These results indicate that the homeostasis of pTregs in the intestines is maintained even in the absence of CD28, whereas CD28 is required for the maximal suppressive activity of intestinal pTregs. [ABSTRACT FROM AUTHOR]

Motivation: The identification of T-cell epitopes has many profound translational applications in the areas of transplantation, disease diagnosis, vaccine/therapeutic protein development and personalized immunotherapy. While data-driven methods have been widely used for the prediction of peptide binders with notable successes, the structural modeling of peptide binding to MHC molecules is crucial for understanding the underlying molecular mechanism of the immunological processes. Results: We developed GradDock, a structure-based method for the rapid and accurate modeling of peptide binding to MHC Class I (pMHC-I). GradDock explicitly models diverse unbound peptides in vacuo and inserts them into the MHC-I groove through a steered gradient descent with a topological correction process. The simulation process yields diverse structural conformations including native-like peptides. We completely revised the Rosetta score terms and developed a new ranking function specifically for pMHC-I. Using the diverse peptides, a linear programming approach is applied to find the optimal weights for the individual Rosetta score terms. Our examination revealed that a refinement of the dihedral angles and a modification of the repulsion can dramatically improve the modeling quality. GradDock is five-times faster than a Rosetta-based docking approach for pMHC-I. We also demonstrate that the predictive capability of GradDock with the reweighted Rosetta ranking function is consistently more accurate than the Rosetta-based method with the standard Rosetta score (approximately three-times better for a cross-docking set). [ABSTRACT FROM AUTHOR]

Motivation: Unlike conventional microscopy which produces pixelated images, SMLM produces data in the form of a list of localization coordinates—a spatial point pattern (SPP). Often, such SPPs are analyzed using cluster analysis algorithms to quantify molecular clustering within, for example, the plasma membrane. While SMLM cluster analysis is now well developed, techniques for analyzing fibrous structures remain poorly explored. Results: Here, we demonstrate a statistical methodology, based on Ripley’s K-function to quantitatively assess fibrous structures in 2D SMLM datasets. Using simulated data, we present the underlying theory to describe fiber spatial arrangements and show how these descriptions can be quantitatively derived from pointillist datasets. We also demonstrate the techniques on experimental data acquired using the image reconstruction by integrating exchangeable single-molecule localization (IRIS) approach to SMLM, in the context of the fibrous actin meshwork at the T cell immunological synapse, whose structure has been shown to be important for T cell activation. [ABSTRACT FROM AUTHOR]

The lack of persistence of infused T cells is a principal limitation of adoptive immunotherapy in man. Interleukin (IL)-15 can sustain memory T cell expansion when presented in complex with IL-15Rα (15Rα/15). We developed a novel in-vitro system for generation of stable 15Rα/15 complexes. Immunologically quantifiable amounts of IL-15 were obtained when both IL-15Rα and IL-15 genes were co-transduced in NIH 3T3 fibroblast-based artificial antigen-presenting cells expressing human leucocyte antigen (HLA) A:0201, β2 microglobulin, CD80, CD58 and CD54 [A2-artificial antigen presenting cell (AAPC)] and a murine pro-B cell line (Baf-3) (A2-AAPC15Rα/15and Baf-315Rα/15). Transduction of cells with IL-15 alone resulted in only transient expression of IL-15, with minimal amounts of immunologically detectable IL-15. In comparison, cells transduced with IL-15Rα alone (A2-AAPCRα) demonstrated stable expression of IL-15Rα; however, when loaded with soluble IL-15 (sIL-15), these cells sequestered 15Rα/15 intracellularly and also demonstrated minimal amounts of IL-15. Human T cells stimulated in vitro against a viral antigen (CMVpp65) in the presence of 15Rα/15 generated superior yields of high-avidity CMVpp65 epitope-specific T cells [cytomegalovirus-cytotoxic T lymphocytes (CMV-CTLs)] responding to ≤ 10− 13 M peptide concentrations, and lysing targets cells at lower effector : target ratios (1 : 10 and 1 : 100), where sIL-15, sIL-2 or sIL-7 CMV-CTLs demonstrated minimal or no activity. Both soluble and surface presented 15Rα/15, but not sIL-15, sustained in-vitro expansion of CD62L+ and CCR7+ central memory phenotype CMV-CTLs (TCM). 15Rα/15 complexes represent a potent adjuvant for augmenting the efficacy of adoptive immunotherapy. Such cell-bound or soluble 15Rα/15 complexes could be developed for use in combination immunotherapy approaches. [ABSTRACT FROM AUTHOR]

Immune senescence as well as disturbed CD8+ T cell differentiation are a hallmark of chronic HIV infection. Here, we investigated to what extent immune senescence is reversible after initiation of anti-retroviral treatment (ART). Peripheral blood mononuclear cells (PBMCs) from a cohort of HIV patients with different disease courses, including untreated viral controllers ( n = 10), viral non-controllers ( n = 16) and patients on ART ( n = 20), were analysed and compared to uninfected controls ( n = 25) by flow cytometry on bulk and HIV-specific major histocompatibility complex (MHC) class I tetramer+ CD8+ T cells for expression of the memory markers CCR7 and CD45RO, as well as the senescence marker CD57 and the differentiation and survival marker CD127. Furthermore, a subset of patients was analysed longitudinally before and after initiation of ART. Frequencies of CD57+CD8+ T cells decreased after initiation of ART in central memory (Tcm) but not in effector memory T cell populations (TemRO and TemRA). The frequency of CD127+CD8+ cells increased in Tcm and TemRO. We observed a reduction of CD127- T cells in Tcm, TemRO and partially in TemRA subsets after initiation of ART. Importantly, HIV-specific CD8+ TemRO cells predominantly displayed a CD127-CD57+ phenotype in untreated HIV-patients, whereas the CD127+CD57- phenotype was under-represented in these patients. The frequency of the CD127+CD57-CD8+ T cell subpopulation correlated strongly with absolute CD4+ counts in HIV-infected patients before and after initiation of ART. These findings can be interpreted as a phenotypical correlate of CD8+ memory T cell differentiation and the premature 'ageing' of the immune system, which was even observed in successfully virally suppressed HIV patients. [ABSTRACT FROM AUTHOR]

The number of elderly patients with end-stage renal disease (ESRD) has increased significantly during the last decade. Elderly ESRD patients are vulnerable to infectious complications because of an aged immune system. Additional immunological ageing effects may be derived from the uraemic environment and cytomegalovirus (CMV) latency. Elderly patients may be affected by these factors in particular, but data in this age group are limited. To assess the degree of immunological ageing and proliferative capacity of T lymphocytes, 49 elderly ESRD patients (defined as aged ≥ 65 years) on the renal transplantation waiting list were recruited and compared to 44 elderly healthy individuals (HI), matched for age and CMV serostatus. CMV latency was associated with more highly differentiated CD4+ and CD8+ T cells in both elderly HI and patients. Elderly CMV seropositive ESRD patients showed a substantial reduction in the number of naive CD4+ and CD8+ T cells compared with age- and CMV serostatus-matched HI. Elderly ESRD patients also showed significantly decreased numbers of central memory CD4+ and CD8+ T cells compared with HI, independently of CMV serostatus. In addition, thymic output and relative telomere length of both CD4+ and CD8+ T cells were decreased in CMV seropositive ESRD patients compared with HI. The proliferative capacity of T cells was similar for patients and HI. Elderly ESRD patients have an advanced aged T cell compartment when compared to age-matched healthy controls, which is driven mainly by CMV latency. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Tregs) constitute a fascinating subpopulation of CD4+ T cells due to their ability to limit the immune response against self and non-self antigens. Murine models and antibodies directed against surface and intracellular molecules have allowed elucidation of the mechanisms that govern their development and function. However, these markers used to their classification lack of specificity, as they can be expressed by activated T cells. Similarly, there are slight differences between animal models, in steady state and pathological conditions, anatomical localization and strategy of analysis by flow cytometry. Here, we revised the most common markers utilized for Treg typification by flow cytometry such as CD25, forkhead box protein 3 (FoxP3) and CD127, along with our data obtained in different body compartments of humans, mice and rats. Furthermore, we revised and determined the expression of other molecules important for the phenotypical characterization of Treg cells. We draw attention to the drawbacks of those markers used in chronic states of inflammation. However, until a specific marker for the identification of Tregs is discovered, the best combination of markers will depend upon the tissue or the degree of inflammation from which Tregs derive. [ABSTRACT FROM AUTHOR]

Chromogranin A (ChgA) is an antigenic target of pathogenic CD4+ T cells in a non-obese diabetic (NOD) mouse model of type 1 diabetes (T1D). Vasostatin-1 is a naturally processed fragment of ChgA. We have now identified a novel H2-Kd-restricted epitope of vasostatin-1, ChgA 36-44, which elicits CD8+ T cell responses in NOD mice. By using ChgA 36-44/Kd tetramers we have determined the frequency of vasostatin-1-specific CD8+ T cells in pancreatic islets and draining lymph nodes of NOD mice. We also demonstrate that vasostatin-1-specific CD4+ and CD8+ T cells constitute a significant fraction of islet-infiltrating T cells in diabetic NOD mice. Adoptive transfer of T cells from ChgA 36-44 peptide-primed NOD mice into NOD/severe combined immunodeficiency (SCID) mice led to T1D development. These findings indicate that vasostatin-1-specific CD8+ T cells contribute to the pathogenesis of type 1 diabetes in NOD mice. [ABSTRACT FROM AUTHOR]

Recent studies highlight the implication of innate and adaptive immunity in the pathophysiology of Alzheimer's disease, and foster immunotherapy as a promising strategy for its treatment. Vaccines targeting amyloid-β peptide provided encouraging results in mouse models, but severe side effects attributed to T cell responses in the first clinical trial AN1792 underlined the need for better understanding adaptive immunity in Alzheimer's disease. We previously showed that regulatory T cells critically control amyloid-β-specific CD4(+) T cell responses in both physiological and pathological settings. Here, we analysed the impact of regulatory T cells on spontaneous disease progression in a murine model of Alzheimer's disease. Early transient depletion of regulatory T cells accelerated the onset of cognitive deficits in APPPS1 mice, without altering amyloid-β deposition. Earlier cognitive impairment correlated with reduced recruitment of microglia towards amyloid deposits and altered disease-related gene expression profile. Conversely, amplification of regulatory T cells through peripheral low-dose IL-2 treatment increased numbers of plaque-associated microglia, and restored cognitive functions in APPPS1 mice. These data suggest that regulatory T cells play a beneficial role in the pathophysiology of Alzheimer's disease, by slowing disease progression and modulating microglial response to amyloid-β deposition. Our study highlights the therapeutic potential of repurposed IL-2 for innovative immunotherapy based on modulation of regulatory T cells in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Several studies have analyzed the potential of T regulatory cells (Treg cells) as biomarkers of acute rejection (AR). The aim of the present multicenter study was to correlate the percentage of peripheral Treg cells in liver graft recipients drawn at baseline up to 12 months after transplantation with the presence of AR. The percentage of central memory (cm) Treg cells (CD4+CD25highCD45RO+CD62L+) was monitored at pre-transplant and at 1 and 2 weeks, and 1, 2, 3 and 6 months and 1 year posttransplantation. The same validation standard operating procedures were used in all participating centers. Fifteen patients developed AR (23.4%). Hepatitis C virus recurrence was observed in 16 recipients, who displayed low peripheral blood cmTreg levels compared with patients who did not. A steady increase of cmTregs was observed during the first month after transplantation with statistically significant differences between AR and non-AR patients. The high frequency of memory Treg cells allowed us to monitor rejection episodes during the first month post-transplantation. On the basis of these data, we developed a prediction model for assessing risk of AR that can provide clinicians with useful information for managing patients individually and customizing immunosuppressive therapies. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Tregs), which could be down-regulated by IL-28B, were reported to suppress T-cell-mediated immunity. The aim of this study was to investigate the role of IL-28B on the immune responses and protective efficacy of a tuberculosis (TB) subunit vaccine. First, a recombinant adenoviral vector expressing mouse IL-28B (rAd-mIL-28B) was constructed; then C57BL/6 mice were immunized with subunit vaccine ESAT6-Ag85B-Mpt64(190-198)-Mtb8.4-HspX (EAMMH) and rAd-mIL-28B together thrice or primed with Mycobacterium bovis bacillus Calmette-Guérin (BCG) and boosted by EAMMH and rAd-mIL-28B twice. At last the immune responses were evaluated, and the mice primed with BCG and boosted by subunit vaccines were challenged with virulent Mycobacterium tuberculosis H37Rv to evaluate the protective efficacy. The results showed that rAd-mIL-28B treatment significantly down-regulated the frequency of Tregs at 4 weeks after the last immunization but did not increase the Th1-type immune responses. Moreover, in the regimen of BCG priming and EAMMH boosting, rAd-mIL-28B treatment did not increase the antigen-specific cellular and humoral immune responses, and consequently did not reduce the bacteria load following H37Rv challenge. Instead, it induced more serious pathology reaction. In conclusion, IL-28B down-regulates Tregs following EAMMH vaccination but does not improve the protective immune responses. [ABSTRACT FROM AUTHOR]

With the Food and Drug Administration and other worldwide regulatory authorities' approval of ipilimumab (Yervoy), sipuleucel-T (Provenge), nivolumab (Opdivo), and pembrolizumab (Keytruda), oncologic therapy has now moved into noncancer cell targets within the immune system. For many nonimmunologists, understanding how these vastly different therapies work to improve survival, like no other therapies have in the past, is a challenge. The present report reviews the normal function of the immune system, how cancers escape the normal immune system, and how these new therapies improve immune system reactions against cancers. [ABSTRACT FROM AUTHOR]

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-α 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. [ABSTRACT FROM AUTHOR]

Chronic inflammation contributes to cancer development via multiple mechanisms. One potential mechanism is that chronic inflammation can generate an immunosuppressive microenvironment that allows advantages for tumor formation and progression. The immunosuppressive environment in certain chronic inflammatory diseases and solid cancers is characterized by accumulation of proinflammatory mediators, infiltration of immune suppressor cells and activation of immune checkpoint pathways in effector T cells. In this review, we highlight recent advances in our understanding of how immunosuppression contributes to cancer and how proinflammatory mediators induce the immunosuppressive microenvironment via induction of immunosuppressive cells and activation of immune checkpoint pathways. [ABSTRACT FROM AUTHOR]

Objective. IL-35 is the most recently identified member of the IL-12 family. It consists of EBV-induced gene 3 (EBI3) and IL-12α chain p35. We investigated whether IL-35 enhances the in vitro immunosup-pressive function of peripheral blood isolated from patients with RA. Methods. Peripheral blood was harvested from 17 active and 10 inactive RA patients and IL-35 concentrations were quantified using an ELISA. An expression vector containing IL-35 with a FLAG tag at the carboxyl-terminus was constructed by covalently linking EBI3 and IL-12α (p35). The function of IL-35 was then evaluated in a suppression assay using T cells isolated from human RA patients with CD2, CD3 and CD28 antibodies. Results. Serum IL-35 levels and the number of Treg were decreased significantly in patients with active RA. There was a significant correlation between serum IL-35 and the 28-joint DAS with ESR (DAS28-ESR) in patients with active RA. IL-35 treatment enhanced the regulatory function, suppressing the levels of inflammatory cytokines such as IL-17 and IFN-γ and the cellular growth of effector T cells stimulated by conjugation with CD2, CD3 and CD28. Conclusion. These data revealed that IL-35 might suppress T cell activation during the peripheral immune responses of RA. Therefore our data suggest that IL-35 might have multiple therapeutic targets. [ABSTRACT FROM AUTHOR]

Objective. Many cytokines involved in RA activate the Janus kinase–signal transducer and activator of transcription (JAK-STAT) pathways. Therapeutic drugs that inhibit these pathways are being developed for RA. To investigate disease-related alterations in the activity of JAK-STAT pathways in RA, we studied the expression and activation of STAT1 and STAT3 in unstimulated and cytokine-stimulated cells and determined the levels of circulating cytokines. Methods. The expression of STAT1 and STAT3 mRNA in peripheral blood (PB) and SF T cells and monocytes was studied in RA patients and healthy volunteers by RT-PCR. Basal and cytokine (IFN-γ, IL-6, IL-10)-induced STAT phosphorylation was analysed in PB T cells and monocytes using multicolour flow cytometric analysis. Results. STAT3 mRNA levels were up-regulated in both PB and SF T cells and monocytes from RA patients. STAT1 expression was elevated in SF monocytes. The levels of phospho-STAT3 in resting PB T cells and monocytes were significantly higher in patients with RA than in healthy volunteers. IL-6 levels were elevated in RA plasma and correlated with the level of STAT3 phosphorylation in CD4+ T cells and monocytes. IL-6-mediated STAT3 activation was deregulated in T cells from RA patients. IL-6-induced phosphorylation of STAT3 was decreased in CD4+ T cells from patients with high plasma IL-6 levels and constitutive STAT3 phosphorylation. Conclusion. The results suggest that IL-6 induces hyperactivation of STAT3 in circulating immune cells in active RA, and this subsequently desensitizes the IL-6 response in T cells. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Treg) are functionally defective in patients with RA. Restoring their function may not only control inflammation but also restore tolerance in these patients. Biologic therapies have been tremendously successful in treating RA. Here we review numerous reports suggesting that these immunomodulatory therapies have an impact on Treg and that this may contribute to their beneficial effects. Better understanding of their mode of action may not only lead to improvements in therapies and sustained remission but also enable the development of biomarkers of response, which would be the first steps towards personalized medicine. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to investigate the turnover of Treg cells in the SF of RA patients. Methods. Treg cells were enumerated in peripheral blood and SF of RA patients and analysed by flow cytometry for expression of the proliferation marker Ki-67 and binding of the apoptosis marker annexin V. Sorted Treg cells of RA patients were analysed for expression of anti-apoptotic regulators Bcl-2 and microRNA-21 (miR-21) by RT-PCR. Results. Treg cells displaying a memory phenotype were abundant in the SF of RA patients. SF Treg cells more frequently expressed the proliferation marker Ki-67 than conventional T cells. Only few SF Treg cells were apoptotic, as indicated by limited annexin V staining of these cells. SF Treg cells displayed high transcription levels of Bcl-2 and miR-21 in comparison with SF conventional T cells and peripheral blood Treg cells. Conclusion. Treg cells with a memory phenotype accumulate in the SF of RA patients. These Treg cells have a high proliferative activity and demonstrate little apoptosis. The latter finding could be explained by high transcription of Bcl-2 and miR-21 in SF Treg cells. [ABSTRACT FROM AUTHOR]

Objective. Increased numbers of IL-17-producing CD4+ T cells have been observed in AS. However, it is not known whether these CD4+ T cells are already present in early disease or if this is a late disease phenomenon only. Therefore we aimed to investigate whether IL-17-producing CD4+ T cells are involved in early active axial SpA, including patients without imaging abnormalities, by determining the frequency and phenotype of IL-17-producing CD4+ T cells in these patients. Methods. Flow cytometry was used to analyse cytokine production and surface marker expression of peripheral blood mononuclear cells from 31 patients suffering from early active HLA-B27-positive axial SpA fulfilling the Assessment of SpondyloArthritis International Society criteria with or without MRI abnormalities and 21 healthy controls. Results. Patients with early active axial SpA showed an increased percentage of IL-17-producing CD4+ T cells compared with healthy controls (mean 1.1% vs 0.4%, respectively; P = 0.013). The percentage of IL-17-producing CD4+ T cells was equally increased in patients with and without MRI abnormalities (1.2% vs 1.1%, respectively; P = 0.81). These IL-17-producing CD4+T cells expressed the αβT cell receptor but not the γδ T cell receptor, exhibited a memory phenotype and expressed CD161, but only sporadically expressed killer cell immunoglobulin-like receptor 3DL2 (KIR3DL2). Conclusion. IL-17-producing CD4+ T cells are increased in patients with early active axial SpA both with and without MRI abnormalities. This finding shows that the frequency of IL-17-producing CD4+ T cells is enhanced in the early stages of disease. [ABSTRACT FROM AUTHOR]

Objectives. We aimed to assess the effect of tocilizumab (TCZ), an IL-6 receptor inhibitor, on B, T, NK and NKT cells in patients with RA and to study the cell type predictors of remission. We also compared NK cells in patients with RA and in controls. Methods. RA patients included in the study met the 2010 ACR/European League Against Rheumatism (EULAR) criteria, were receiving stable doses of steroids and had not received rituximab in the previous year. Different B and T cell subsets, NK cells and NKT cells were assessed by flow cytometry along with perforin A and granzyme B to estimate NK cell cytotoxicity. Results. We included 92 RA patients, including 20 requiring TCZ treatment and 15 requiring anti-TNF drugs, and 25 controls. At baseline, the proportion of CD56dimCD16+CD3- NK cells was inversely correlated with the 28-joint DAS (DAS28). In TCZ-treated patients, the baseline proportion of CD3_CD56+ NK cells was inversely correlated with the change in DAS28 at 3 months and the proportion was 3-fold greater for patients with DAS28 remission at 3 months than other patients. Change in the proportion of CD56briCD16- NK cells was linearly correlated with change in the DAS28 at 3 months. The baseline proportion of NK cells did not predict change in disease activity at 3 months with anti-TNF therapy. The perforin content in NK cells increased with TCZ treatment. Conclusion. This study supports NK cell involvement in RA and in the TCZ mechanism of action. NK cells at baseline could be a predictive factor of TCZ response if results are confirmed. [ABSTRACT FROM AUTHOR]

Objective. CD200/CD200R1 signalling has an immunoregulatory effect on the activation threshold of the inflammatory immune response and maintains immune homeostasis. In this study we evaluated the status of CD200/CD200R1 interaction in patients with RA. Methods. The expression of CD200 and CD200R1 was examined by immunohistochemistry and flow cytometry and was compared between RA patients and healthy controls (HCs). Sorted CD4+ T cells were stained with carboxyfluorescein succinimidyl ester (CFSE) and annexin V-propidium iodide to evaluate the effect of CD200 on cell proliferation and apoptosis. The effect of CD200 on Th17 differentiation, function and osteoclastogenesis was determined by flow cytometry, transwell migration assay and immunocytochemistry, respectively. Results. The proportion of CD200+ cells and CD200R1+ cells in peripheral blood mononuclear cells, peripheral CD14+ cells and CD4+ T cells was significantly lower in the RA patients than in HCs, whereas the number of CD200+ cells was higher in synovium from RA patients than in that from HCs. After treatment with infliximab and MTX we found increased expression of peripheral CD200/CD200R1 that correlated with a decrease in the 28-joint DAS. CD200Fc in vitro partially inhibited CD4+ T cell proliferation, promoted CD4+ T cell apoptosis, reduced CD4+ T cell differentiation into Th17 cells and down-regulated CCR6-mediated Th17 chemotaxis in cells from RA patients. In addition, the engagement of the CD200 receptors on CD14+ cells with CD200Fc in vitro reduced osteoclastogenesis and inhibited CD14+ celldriven Th17 differentiation. Conclusion. Abnormal CD200/CD200R1 expression in RA may contribute to abnormal Th17 cell differentiation, chemotaxis and osteoclastogenesis. [ABSTRACT FROM AUTHOR]

Over the last four decades, increases in the incidence of immune-mediated diseases in the Western world have been linked to changes in microbial exposure. It is becoming increasingly clear that the normal microbiota in the gut can profoundly alter susceptibility to a wide range of diseases, such as asthma, in which immune homeostasis is disrupted, yet the mechanisms governing this microbial influence remains poorly defined. In this study, we showthat gastrointestinal exposure to PSA, a capsular polysaccharide derived from the commensal bacterium Bacteroides fragilis, significantly limits susceptibility to the induction of experimental asthma. We report that direct treatment of mice with PSA generates protection from asthma, and this effect can be given to a naïve recipient by adoptive transfer of CD4+ T cells from PSA-exposed mice. Remarkably, we found that these PSA-induced T cells are not canonical FoxP3+ regulatory T cells, but that they potently inhibit both Th1 and Th2 models of asthma in an IL-10-dependent fashion. These findings reveal that bacterial polysacchar-ides link the microbiota with the peripheral immune system by activating CD4+Foxp3- T cells upon exposure in the gut, and they facilitate resistance to unnecessary inflammatory responses via the production of IL-10. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify the proportion of regulatory T cells ( Treg) and cytokine expression by peripheral blood mononuclear cells ( PBMCs) in patients with active non-infectious uveitis, and to evaluate the effect of in-vitro treatment with infliximab, dexamethasone and cyclosporin A on Treg levels and cytokine production in PBMCs from uveitis patients and healthy subjects. We included a group of 21 patients with active non-infectious uveitis and 18 age-matched healthy subjects. The proportion of forkhead box protein 3 ( Fox P3)+ Treg cells and intracellular tumour necrosis factor ( TNF)-α expression in CD4+ T cells was determined by flow cytometry. PBMCs were also either rested or activated with anti- CD3/anti- CD28 and cultured in the presence or absence of dexamethasone, cyclosporin A and infliximab. Supernatants of cultured PBMCs were collected and TNF-α, interleukin ( IL)-10, IL-17 and interferon ( IFN)-γ levels were measured by enzyme-linked immunosorbent assay ( ELISA). No significant differences were observed in n Treg levels between uveitis patients and healthy subjects. However, PBMCs from uveitis patients produced significantly higher amounts of TNF-α and lower amounts of IL-10. Dexamethasone treatment in vitro significantly reduced Fox P3+ Treg levels in PBMCs from both healthy subjects and uveitis patients, and all tested drugs significantly reduced TNF-α production in PBMCs. Dexamethasone and cyclosporin A significantly reduced IL-17 and IFN-γ production in PBMCs and dexamethasone up-regulated IL-10 production in activated PBMCs from healthy subjects. Our results suggest that PBMCs from patients with uveitis express more TNF-α and less IL-10 than healthy subjects, and this is independent of Fox P3+ Treg levels. Treatment with infliximab, dexamethasone and cyclosporin A in vitro modulates cytokine production, but does not increase the proportion of Fox P3+ Treg cells. [ABSTRACT FROM AUTHOR]

The role of T cells in idiopathic inflammatory myopathies ( IIM) is not yet clear. Some alterations in certain subsets have been reported in inflamed muscle cells. However, a broad quantitative assessment of peripheral T cell subsets has not been evaluated. The aim of this study was to address the quantitative profile of potential pathogenic T cell subsets, namely follicular helper T cells ( Tfh), T helper type 17 ( Th17), CD28null and regulatory T cells ( Tregs) in peripheral blood from IIM patients. Thirty IIM patients and 30 age- and gender-matched healthy donors were included. Peripheral blood mononuclear cells were isolated. T cell subsets were evaluated by flow cytometry, as follows: Tfh ( CD4+ CXCR5+) and its subsets Tfh1 ( CXCR3+ CCR6−), Tfh2 ( CXCR3− CCR6−), Tfh17 ( CXCR3− CCR6+), Th17 ( CD4+ IL17 A+), CD28null ( CD4+ CD28− CD244+) and Tregs ( CD4+ CD25high forkhead box protein 3 (FoxP3+); CD8+ CD25high FoxP3+). Percentage, absolute numbers and mean fluorescence intensity were analysed. We found increased numbers of total Tfh cells (28 ± 8·16 versus 6·64 ± 1·29, P = 0·031) in IIM patients when compared to healthy controls. Moreover, this increment was dependent upon Tfh2 and Tfh17 ( Tfh2:9·49 ± 2·19 versus 1·66 ± 0·46, P = 0·005; Tfh17 9·48 ± 2·83 versus 1·18 ± 0·21, P = 0·014). Also, IIM patients showed higher numbers of Th17 cells (30·25 ± 6·49 versus 13·46 ± 2·95, P = 0·031) as well as decreased number of Tregs (5·98 ± 1·61 versus 30·82 ± 8·38, P = 0·009). We also found an expansion of CD28null cells (162·88 ± 32·29 versus 64 ± 17·35, P = 0·015). Our data suggest that IIM patients are characterized by an expansion of peripheral proinflammatory T cells, such as Tfh and Th17, as well as pro-apoptotic CD28 null cells and a deficiency of suppressor populations of Tregs ( CD4+ and CD8+). [ABSTRACT FROM AUTHOR]

Heme oxygenase ( HO)-1, the inducible isoform of HO, has immunomodulatory functions and is considered a target for therapeutic interventions. In the present study, we investigated whether modulation of HO-1 might have regulatory effects on in-vitro T cell activation. The study examined whether: (i) HO-1 induction by cobalt-protoporphyrin ( CoPP) or inhibition by tin-mesoporphyrin ( SnMP) can affect expansion and function of virus-specific T cells, (ii) HO-1 modulation might have a functional effect on other cell populations mediating effects on proliferating T cells [e.g. dendritic cells ( DCs), regulatory T cells ( Tregs) and natural killer cells] and (iii) HO-1-modulated anti-viral T cells might be suitable for adoptive immunotherapy. Inhibition of HO-1 via SnMP in cytomegalovirus ( CMV)pp65-peptide-pulsed peripheral blood mononuclear cells ( PBMCs) led to increased anti-viral T cell activation and the generation of a higher proportion of effector memory T cells ( CD45 RA− CD62 L−) with increased capability to secrete interferon ( IFN)-γ and granzyme B. Treg depletion and SnMP exposure increased the number of anti-viral T cells 15-fold. To test the possibility that HO-1 modulation might be clinically applicable in conformity with good manufacturing practice ( GMP), SnMP was tested in isolated anti-viral T cells using the cytokine secretion assay. Compared to control, SnMP treatment resulted in higher cell counts and purity without negative impact on quality and effector function [ CD107a, IFN-γ and tumour necrosis factor ( TNF)-α levels were stable]. These results suggest an important role of HO-1 in the modulation of adaptive immune responses. HO-1 inhibition resulted in markedly more effective generation of functionally active T cells suitable for adoptive T cell therapy. [ABSTRACT FROM AUTHOR]

Far from being merely a passive cholesterol accumulation within the arterial wall, the development of atherosclerosis is currently known to imply both inflammation and immune effector mechanisms. Adaptive immunity has been implicated in the process of disease initiation and progression interwined with traditional cardiovascular risk factors. Although the body of knowledge regarding the correlation between atherosclerosis and immunity in humans is growing rapidly, a relevant proportion of it derives from studies carried out in animal models of cardiovascular disease ( CVD). However, while the mouse is a well-suited model, the results obtained therein are not fully transferrable to the human setting due to intrinsic genomic and environmental differences. In the present review, we will discuss mainly human findings, obtained either by examination of post-mortem and surgical atherosclerotic material or through the analysis of the immunological profile of peripheral blood cells. In particular, we will discuss the findings supporting a pro-atherogenic role of T cell subsets, such as effector memory T cells or the potential protective function of regulatory T cells. Recent studies suggest that traditional T cell-driven B2 cell responses appear to be atherogenic, while innate B1 cells appear to exert a protective action through the secretion of naturally occurring antibodies. The insights into the immune pathogenesis of atherosclerosis can provide new targets in the quest for novel therapeutic targets to abate CVD morbidity and mortality. [ABSTRACT FROM AUTHOR]

SS is a chronic systemic autoimmune disease characterized by decreased exocrine gland function. A variety of other disease manifestations may also be present, including general constitutional symptoms and extraglandular features. A multidisciplinary approach focused on both local and systemic medical therapies is needed as the disease has a wide clinical spectrum. The current treatment for SS is mainly symptomatic. However, there is evidence that systemic drugs are effective in controlling extraglandular manifestations of the disease. Overall evidence for the role of conventional immunosuppressive therapy is limited. A number of attempts to use biologic therapies have led to variable results. Biologic agents targeting B cells, such as rituximab, epratuzumab and belimumab, have shown promising results, but further studies are needed to validate the findings. Early-phase studies with abatacept and alefacept proved that T cell stimulation inhibition is another potentially effective target for SS treatment. Modulation or inhibition of other targets such as IFN, IL-6 and Toll-like receptor are also currently being investigated. We have summarized the available evidence regarding the efficacy of biologic treatments and discuss other potential therapies targeting pathways or molecules recognized as being involved in the pathogenesis of SS. [ABSTRACT FROM PUBLISHER]

Objective. The aim of this study was to investigate the effect of umbilical cord mesenchymal stem cells (UC-MSCs) on circulating T follicular helper (cTfh) cells in primary SS (pSS) patients.Methods. The percentage of CXCR5+PD-1+CD4+ T cells in peripheral blood mononuclear cells (PBMCs) was analysed by flow cytometry. PBMCs were co-cultured with UC-MSCs by cell-to-cell contact or in a trans-well system. Naive CD4+ T cells were isolated from PBMCs and then co-cultured with UC-MSCs under Tfh cell-polarizing conditions. The percentage of CXCR5+PD-1+CD4+ T cells, carboxyfluorescein succinimidyl ester (CFSE) fluorescence intensity and annexin V were determined by flow cytometric analysis. Real-time PCR and Luminex cytokine assay were performed to detect mRNA expression and supernatant protein levels. The activity of indoleamine 2,3-dioxygenase (IDO) was measured by HPLC.Results. Increased frequency of cTfh cells was found in pSS patients and was positively correlated with serum anti-La/SSB levels and the European League Against Rheumatism SS Disease Activity Index score. In vitro, UC-MSCs suppressed the differentiation and proliferation of cTfh cells. Real-time PCR analysis showed significantly higher IDO mRNA expression on UC-MSCs when co-cultured with naive CD4+ T cells under Tfh cell-polarizing conditions in pSS patients. However, IDO mRNA expression on UC-MSCs was only a little higher when UC-MSCs were co-cultured with naive CD4+ T cells in a trans-well system. In addition, HPLC showed increased IDO enzymic activity in the supernatant of UC-MSCs co-cultured with naive CD4+ T cells under Tfh cell-polarizing conditions in pSS. The addition of the IDO inhibitor 1-MT partly reversed the suppressive effect of UC-MSCs on the differentiation of cTfh cells.Conclusion. These results suggest an inhibitory effect of UC-MSCs on the differentiation of cTfh cells via the secretion of IDO, and soluble factors secreted by activated CD4+ T cells might contribute to IDO secretion by UC-MSCs. [ABSTRACT FROM PUBLISHER]

Objectives. Spleen tyrosine kinase (SYK) is a core signalling protein that drives inflammatory responses and is fundamental to the propagation of signals via numerous immune receptors, including the B cell receptor and Fc receptors (FcRs). Fostamatinib, a small molecule SYK inhibitor, has shown evidence of ameliorating inflammation in RA patients. We sought to understand how the active metabolite of fostamatinib, R406, affects the inflammatory response at the cellular level.Methods. Antigen-specific in vivo systems and in vitro fluorescence microscopy were combined to investigate the effects of fostamatinib on antigen-specific interactions between dendritic cells (DCs) and CD4+ T cells.Results. Although it has previously been shown that R406 reduces the response of DCs to immune complexes (ICs), we found that fostamatinib failed to reduce specific CD4+ T cell proliferation in mice after immunization with ICs. However, we observed in vitro that R406 reduces both the area and duration of cellular interactions between IC-activated DCs and specific CD4+ T cells during the initial phase of cellular crosstalk. This led to diminished proliferation of antigen-specific CD4+ T cells after R406 treatment compared with vehicle controls. This decreased proliferative capacity of CD4+ T cells was accompanied by reduced expression of the co-stimulatory molecules, inducible T cell co-stimulator (ICOS) and PD-1, and abrogation of the production of inflammatory cytokines such as IFN-γ and IL-17.Conclusion. Our findings indicate a potential mechanism by which this compound may be effective in inhibiting FcR-driven CD4+ T cell responses. [ABSTRACT FROM PUBLISHER]

Objective. Human umbilical cord Wharton jelly-derived mesenchymal stem cells (hUCMS) are easy to retrieve in bulk. They may interact with immune cells by either cell contact or soluble factors. Little evidence is currently available on potential therapeutic application of hUCMS to systemic autoimmune disorders such as primary SS (pSS). We have recently developed an endotoxin-free alginate gel that can be used to microencapsulate different cell types for graft into non-immunosuppressed hosts. We aimed to assess the in vitro effects of IFN-γ-pretreated microencapsulated (CpS)-hUCMS on T cells of pSS.Methods. Ten pSS patients and 10 healthy donors were selected. Peripheral blood mononuclear cells (PBMCs) were obtained from venous blood to establish co-cultures with CpS-hUCMS. Lymphocyte proliferation and phenotypic analysis was performed by flow cytometry and real-time PCR on IFN-γ-pretreated hUCMS was performed before PBMCs co-culture.Results. We found that CpS-hUCMS suppress pSS T cell proliferation and restore the Treg/Th17 ratio, thereby possibly positively impacting the pSS disease process.Conclusion. We have developed a new biohybrid drug delivery system that now waits for clinical application in autoimmune diseases, including pSS. [ABSTRACT FROM PUBLISHER]

Objectives. Nuclear factor κB (NF-κB) is a critical activator of inflammatory processes and MTX is one of the most commonly prescribed DMARDs for treatment of RA. We sought to determine whether MTX inhibited NF-κB activity in RA and in lymphocytes and fibroblast-like synoviocytes (FLSs) and to define underlying mechanisms of action.Methods. An NF-κB luciferase reporter plasmid was used to measure NF-κB activation across experimental stimuli. Flow cytometry was used to quantify changes in intracellular protein levels, measure levels of reactive oxygen species and determine apoptosis. Quantitative RT-PCR was used to identify changes in MTX target genes.Results. In T cell lines, MTX (0.1 μM) inhibited activation of NF-κB via depletion of tetrahydrobiopterin (BH4) and increased Jun-N-terminal kinase (JNK)-dependent p53 activity. Inhibitors of BH4 activity or synthesis also inhibited NF-κB activation and, similar to MTX, increased JNK, p53, p21 and JUN activity. Patients with RA expressed increased levels of phosphorylated or active RelA (p65) compared with controls. Levels of phosphorylated RelA were reduced in patients receiving low-dose MTX therapy. In contrast, inhibition of NF-κB activation by MTX was not mediated via BH4 depletion and JNK activation in FLSs, but rather was completely prevented by adenosine receptor antagonists.Conclusion. Our findings support a model whereby distinct pathways are activated by MTX in T cells and FLSs to inhibit NF-κB activation. [ABSTRACT FROM PUBLISHER]

Objective. Interstitial pneumonia (IP) is a chronic progressive interstitial lung disease associated with high mortality and poor prognosis. However, the pathogenesis of IP remains to be elucidated. The aim of this study was to clarify the role of CD161+ Vδ1+ γδ T cells in SSc patients with IP.Methods. The proportion of CD161+ Vδ1+ γδ T cells in peripheral blood mononuclear cells (PBMCs) and serum sialylated carbohydrate antigen (KL-6) levels were determined. GeneChip analysis was performed with CD161− and CD161+ Vδ1+ γδ T cells. Cytokine and chemokine expression from CD161+ Vδ1+ γδ T cells was measured and used to evaluate the effect of culture supernatant on fibroblast proliferation.Results. The proportion of CD161+ Vδ1+ γδ T cells was significantly higher in SSc than healthy controls (HCs) and correlated negatively with serum KL-6 levels in IP-positive SSc patients. The gene and mRNA expression level of chemokine ligand 3 (CCL3) was markedly higher in CD161+ Vδ1+ γδ T cells than in CD161− Vδ1+ γδ T cells. CD161+ Vδ1+ γδ T cells in IP-positive SSc patients showed higher production of CCL3 and lower production of IFN-γ than in HCs. Culture supernatant derived from IP-negative and IP-positive SSc patients promoted fibroblast proliferation, whereas that from HCs did not.Conclusion. The small proportion and the altered cell functions of CD161+ Vδ1+ γδ T cells among PBMCs in SSc patients play a role in the pathogenesis of IP. These findings suggest that CD161+ Vδ1+ γδ T cells may play a regulatory role in the pathogenesis of IP in SSc patients via IFN-γ production. [ABSTRACT FROM PUBLISHER]

Functional analysis of single Toll-like receptors ( TLRs) in vivo is necessary to understand how they shape the ocular inflammation involved in uveitis. In this study we explored the role and mechanisms of TLR-2 agonists on the autoreactive T helper type 17 ( Th17) response in experimental autoimmune uveitis ( EAU). Treatment by peptidoglycan ( PGN), a specific TLR-2 agonist, remarkably increased mRNA levels of Th17-lineage genes interleukin ( IL)-17 A, IL-21 and RAR-related orphan receptor (RO R)γt and promoted antigen-specific Th17 response in EAU mice. A mixture of PGN and interphotoreceptor retinoid-binding protein peptide ( IRBP161-180) could effectively induce EAU in the absence of complete Freund's adjuvant ( CFA). PGN treatment also enhanced the pathogenic activities of activated antigen-specific Th17 cells in vivo. PGN significantly increased the production of IL-1β, IL-6 and IL-23 of dendritic cells ( DCs) and enhanced their ability to promote IL-17+ uveitogenic T cells. Enhanced immunostimulatory activities of PGN- DCs depend upon p38 activation. Inhibition of p38 mitogen-activated protein kinase ( MAPK) activity dramatically decreased IL-17 gene expression and antigen-specific Th17 responses stimulated by PGN- DCs. Our findings suggest that PGN treatment dramatically promotes the IL-17+ uveitogenic T cell responses via enhancing the immunostimulatory activities of DCs. This effect may be mediated, at least in part, by activation of the p38 signalling pathway in DCs. [ABSTRACT FROM AUTHOR]

The biologically active form of vitamin D3, 1, 25-dihydroxyvitamin D3 (calcitriol), is a potent modulator of the immune response. We have shown previously that calcitriol modulates the immunoglobulin response in vitro and in vivo in mice and humans. To analyse the underlying molecular mechanisms we studied whether calcitriol-primed B cells modulate T cell activation and function. Human B cells were stimulated with anti- CD40 and interleukin ( IL)-4 in the presence of increasing concentrations of calcitriol. After removal of calcitriol, primed B cells were co-cultured with autologous CD4+ T cells; the B cell phenotype T cell activation and their consecutive cytokine production were also assessed. Naive T cells co-cultured with calcitriol-primed naive B cells showed a reduced expansion, nuclear factor of activated T cells, cytoplasmic 2 ( NFATc2) expression and cytokine production upon restimulation. CD86 expression on B cells after calcitriol priming was identified as an underlying mechanism, as T cell activation and expansion was rescued by activating anti- CD28 antibodies. Our data indicate that calcitriol-primed B cells display an impaired capacity to activate T cells. Taken together, we identified a novel B cell-dependent vitamin D immune regulatory mechanism, namely by decreased co-stimulation of calcitriol-primed B cells. [ABSTRACT FROM AUTHOR]

The objective of this study is to evaluate urinary high mobility group box 1 ( HMGB1) levels as markers for active nephritis in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis ( AAV) in comparison with urinary CD4+ effector memory T cells and urinary monocyte chemoattractant protein-1 ( MCP-1). Twenty-four AAV patients with active nephritis and 12 healthy controls ( HC) were evaluated. In nine patients, samples were also obtained during remission. Urinary levels of HMGB1 were measured by Western blot. CD4+ T cells and CD4+ effector memory T cells ( CD4+ CD45 RO+ CCR7-) were determined in urine and whole blood by flow cytometry. Measurement of urinary levels of MCP-1 and serum HMGB1 levels were performed by enzyme-linked immunosorbent assay ( ELISA). AAV patients with active nephritis had higher median intensity of HMGB1 in urine than HC [10·3 (7·05-18·50) versus 5·8 (4·48-7·01); P = 0·004]. Both urinary HMGB1 and MCP-1 levels decreased significantly from active nephritis to remission. The urinary MCP-1/creatinine ratio correlated with Birmingham Vasculitis Activity Score ( BVAS) ( P = 0·042). No correlation was found between the HMGB1/creatinine ratio and 24-h proteinuria, estimated glomerular filtration rate (eGFR), MCP-1/creatinine ratio, BVAS and serum HMGB1. A positive correlation was found between urinary HMGB1/creatinine ratio and CD4+ T cells/creatinine ratio ( P = 0·028) and effector memory T cells/creatinine ratio ( P = 0·039) in urine. Urinary HMGB1 levels are increased in AAV patients with active nephritis when compared with HC and patients in remission, and urinary HMGB1 levels are associated with CD4+ T cells and CD4+ effector memory T cells in urine. Measurement of urinary HMGB1 may be of additional value in identifying active glomerulonephritis in AAV patients. [ABSTRACT FROM AUTHOR]

Treatment of primary biliary cirrhosis ( PBC) has lagged behind that of other autoimmune diseases. In this study we have addressed the potential utility of immunotherapy using regulatory T cells ( Treg) to treat murine autoimmune cholangitis. In particular, we have taken advantage of our ability to produce portal inflammation and bile duct cell loss by transfer of CD8+ T cells from the dominant negative form of transforming growth factor beta receptor type II ( dnTGF-β RII) mice to recombination-activating gene ( Rag)1-/- recipients. We then used this robust established adoptive transfer system and co-transferred CD8+ T cells from dnTGF-β RII mice with either C57 BL/6 or dnTGF-β RII forkhead box protein 3 ( FoxP3+) T cells. Recipient mice were monitored for histology, including portal inflammation and intralobular biliary cell damage, and also included a study of the phenotypical changes in recipient lymphoid populations and local and systemic cytokine production. Importantly, we report herein that adoptive transfer of Treg from C57 BL/6 but not dnTGF-β RII mice significantly reduced the pathology of autoimmune cholangitis, including decreased portal inflammation and bile duct damage as well as down-regulation of the secondary inflammatory response. Further, to define the mechanism of action that explains the differential ability of C57 BL/6 Treg versus dnTGF-β RII Treg on the ability to down-regulate autoimmune cholangitis, we noted significant differential expression of glycoprotein A repetitions predominant (GA RP), CD73, CD101 and CD103 and a functionally significant increase in interleukin ( IL)-10 in Treg from C57 BL/6 compared to dnTGF-β RII mice. Our data reflect the therapeutic potential of wild-type CD4+ FoxP3+ Treg in reducing the excessive T cell responses of autoimmune cholangitis, which has significance for the potential immunotherapy of PBC. [ABSTRACT FROM AUTHOR]

Background and Aim: The purpose of this study was to assess the relationship of pleural adenosine deaminase (P-ADA) and non-Hodgkin’s lymphoma (NHL).Design and Methods: We retrospectively analysed 63 NHL patients with pleural effusions who accepted a diagnostic thoracentesis and who had P-ADA available at the China Medical University Hospital (Taichung, Taiwan) between January 2003 and April 2012.Results: There were 46 exudates [40 malignant pleural effusions (MPE), 5 complicated para-pneumonic effusions and 1 undiagnosed effusion] and 17 transudates. The P-ADA activity was significantly different between the two groups (P < 0.005). Among 40 MPE cases, 29 were due to B-cell and 11 due to T-cell NHL. There was no pleural transudative effusion with P-ADA value higher than 26 U/l in our study, but simultaneously 48% (22/46) of exudative pleural effusions showed a P-ADA value under that cut-off point. The P-ADA level reached the diagnostic cut-off for tuberculosis (40 IU/l) in 11 cases of MPE (11/40 = 27.5%): 9 B-cell NHL (9/29 = 31%) and 2 T-cell NHL (2/11 = 18%). The median levels (25th, 75th percentiles) of P-ADA were 28 IU/l (14–50) in the MPE of B-cell NHL and 26 IU/l (14–28) in the T-cell NHL (P = 0.693).Conclusions: The use of P-ADA in NHL effusion could aid the separation of transudates from exudates. Around one-quarter MPE of NHL had abnormal P-ADA ( > 40 IU/l). There was no difference in the P-ADA activity in T-cell and B-cell NHL. [ABSTRACT FROM AUTHOR]

Objective. CD70-expressing CD4 T cells are enriched in RA and promote autoimmunity via co-stimulatory CD70-CD27 interaction. This study aimed to explore the phenotype and cytokine production of CD70+ CD4 T cells in RA.Methods. Peripheral blood mononuclear cells from 32 RA patients were isolated and frequencies of CD70+ cells within different CD4 T subsets were analysed using flow cytometry. IFN-γ and IL-17 production were compared between the CD70+ and CD70− cells. Expression of master transcription factors T-bet, GATA3 and retinoic acid–related orphan receptor gamma t (RORγt) were examined by real-time PCR. Results are presented as mean (s.e.m.).Results. CD4 T cells of healthy controls rarely expressed CD70 as compared with CD4 T cells of RA patients [mean 0.9% (s.e.m. 0.3%) vs 7.6 (0.6), P < 0.001]. In RA, CD70+ cells were present within all CD4 T cell subsets, i.e. CD45RA+CCR7+ naive, CD45RA−CCR7+ central memory, CD45RA−CCR7− effector memory and CD45RA+CCR7− terminally differentiated effector memory T cells with a mean frequency of 3.9% (s.e.m. 1.1%), 4.0 (0.5), 4.2 (0.7) and 9.4 (4.3), respectively. As compared to CD70− CD4 T cells, CD70+ CD4 T cells produced significantly more IFN-γ and IL-17 after short activation. CD70+ CD4 T cells preferentially expressed transcription factor RORγt.Conclusion. CD70+ CD4 T cells are enriched in RA and may directly contribute to RA pathogenesis by producing IFN-γ and IL-17. Targeting CD70+ CD4 T cells might offer new therapeutic opportunities in RA. [ABSTRACT FROM PUBLISHER]

Biologic therapies that target pathogenic cytokines such as TNF, IL-1β or IL-6 have greatly improved the treatment of RA. Unfortunately, not all RA patients respond to current biologic therapies and responses are not always maintained, suggesting that there are alternative drivers of RA pathogenesis that might serve as promising therapeutic targets. Discovery of the new Th17 subset of Th cells, and their role in autoimmune disease development, has implicated the proinflammatory IL-12 and IL-17 families of cytokines in RA disease pathogenesis. Members of these cytokine families are elevated in the blood and joints of RA patients and have been shown to remain elevated in patients who do not respond to current biologics. In addition, these cytokines have been shown to play roles in joint destruction and erosion. A new subclass of biologics that target the IL-12 and/or IL-17 signalling pathways are under development. Here we review evidence for a role of Th17 cells as well as IL-12 and IL-17 cytokines in RA pathogenesis as the rationale for a subsequent discussion of the ongoing and completed clinical trials of newly emerging biologic therapies directed at IL-12 or IL-17 pathway inhibition. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to evaluate the role of rituximab (RTX) in modulating the expression of the IL-17/IL-23 pathway in the salivary glands (SGs) of patients with primary SS (pSS).Methods. Consecutive SG biopsies were obtained from 15 patients with pSS before and after 1 year of RTX therapy. The SG expression of IL-17, IL-23p19 and p-STAT3 was evaluated by immunohistochemistry at baseline and after RTX therapy. The role of mast cells in pSS patients in modulating the Th17 response and the immunologic effect of RTX on mast cells were also studied in in vitro experiments.Results. IL-17 was overexpressed in the SGs of patients with pSS mainly by infiltrating T cells and mast cells. After RTX therapy, the SG expression of IL-17, but not of IL-23p19 and p-STAT3, was significantly reduced and was accompanied by the depletion of tissue mast cells. In in vitro experiments with heterologous peripheral lymphocytes RTX significantly induced the apoptosis of isolated mast cells. Finally, mast cells isolated from peripheral blood mononuclear cells of pSS patients in vitro significantly increased Th17 lymphocytes.Conclusion. RTX acts on pSS patients by globally reducing the expression of IL-17 and specifically inducing a pronounced apoptotic depletion of mast cells. [ABSTRACT FROM PUBLISHER]

Aims Although recent animal studies have investigated the cellular and molecular mechanisms underlying the process of atherosclerosis regression, it remains unknown whether adaptive immune responses including T cells are involved in this process. We investigated the role of T cells in atherosclerosis regression. Methods and results LDL receptor-deficient mice were fed a high-cholesterol diet for 8 weeks to form atherosclerotic lesions and were then changed to a standard diet, and atherosclerosis was assessed 4 weeks later. Just before changing the diet, the mice received an iv injection of anti-CD3 antibody (CD3-Ab) or control immunoglobulin G for 5 consecutive days. CD3-Ab treatment regressed atherosclerosis and decreased the accumulation of macrophages and CD4+ T cells in the plaques. CD3-Ab treatment also dramatically reduced CD4+ T cells and increased the proportion of regulatory T cells (Tregs). Depletion of Tregs by anti-CD25 antibody injection abolished the regression of atherosclerosis seen in CD3-Ab-treated mice, indicating the essential role for Tregs in this process. Conclusion CD3-Ab treatment induced rapid regression of established atherosclerosis via reducing CD4+ T cells and increasing the proportion of Tregs. These findings suggest that therapeutic intervention for T-cell-mediated immune responses may represent a novel strategy to induce atherosclerosis regression in combination with lipid-lowering therapy. [ABSTRACT FROM PUBLISHER]

Objective. Granulomatosis with polyangiitis (GPA) is a rare and sometimes fatal systemic autoimmune disease. ANCAs specific for PR3 are associated with GPA. Remission in GPA can be achieved through B cell depletion (BCD) therapy. Our aim was to understand whether the frequencies of T cell subsets are influenced by BCD.Methods. The frequencies of circulating T follicular helper cells (cTFHs) and regulatory T cells (Tregs) from 36 GPA patients including 11 rituximab-treated patients and 10 healthy controls were studied by flow cytometry. The functional capacity of Tregs was assessed by in vitro co-culture assays.Results. We observed an increased frequency of cTFHs and a reduced frequency of antigen-experienced Tregs in peripheral blood from GPA patients on conventional therapies but not in those treated with rituximab compared with healthy controls. Furthermore, the ratio of cTFHs to Tregs was significantly higher in GPA patients on conventional therapies than in GPA patients treated with rituximab who were clinically improved or controls. Whereas Tregs were numerically reduced in GPA patients on conventional therapy, the suppressive capacity of Tregs on a per cell basis was not significantly altered in these individuals.Conclusion. Our study illustrated increased cTFHs with decreased antigen-experienced Tregs in GPA patients on conventional therapies, but in B cell-depleted patients the levels of cTFHs and Tregs were similar to healthy controls. The negative correlation between cTFHs and Tregs implies the balance between T cell subsets and its B cell dependence impact on disease activity in GPA. [ABSTRACT FROM PUBLISHER]

Objective. The aim of this study was to identify serum markers that are modulated by an investigational anti-IFN-α mAb, sifalimumab, in adult DM or PM patients.Methods. In a phase 1b clinical trial, sera were collected from a total of 48 DM or PM adult patients receiving either placebo for 3 months or sifalimumab for 6 months. Samples were tested for 128 selected proteins using a multiplex luminex immunoassay. Muscle biopsies from selected patients were stained for T cell infiltration using an anti-CD3 antibody.Results. A robust overexpression of multiple serum proteins in DM or PM patients was observed, particularly in patients with an elevated baseline type I IFN gene signature in the blood or muscle. Neutralization of the type I IFN gene signature by sifalimumab resulted in coordinated suppression of T cell-related proteins such as soluble IL-2RA, TNF receptor 2 (TNFR2) and IL-18. Muscle biopsies from two patients with the highest serum protein suppression were selected and found to have a pronounced reduction of muscle T cell infiltration. Down-regulation of IL-2RA correlated with favourable manual muscle test 8 (MMT-8) alterations in sifalimumab-dosed patients.Conclusion. A reduced level of multiple T cell-associated proteins after sifalimumab but not placebo administration suggests a suppressive effect of blocking type I IFN signalling on T cell activation and chemoattraction that may lead to a reduction of T cell infiltration in the muscle of myositis patients. Further, soluble IL-2RA changes from baseline may serve as a responsive and/or predictive marker for type I IFN-targeted therapy in adult DM or PM patients. [ABSTRACT FROM PUBLISHER]

PM and DM are characterized clinically by weakness and low endurance of skeletal muscle. Other organs are frequently involved, suggesting that idiopathic inflammatory myopathies (IIMs) are systemic inflammatory diseases. Involvement of immune mechanisms in IIMs is supported by the presence of T cells, macrophages and dendritic cells in muscle tissue, by the presence of autoantibodies and by HLA-DR being a strong genetic risk factor. T cells may have direct and indirect toxic effects on muscle fibres, causing muscle fibre necrosis and muscle weakness, but the target of the immune reaction is not known. A newly identified T cell subset, CD28null T cells, may have cytotoxic effects in the CD4+ and CD8+ T cell phenotype. These cells are apoptosis resistant and may contribute to treatment resistance. Several myositis-specific autoantibodies have been identified, but they are all directed against ubiquitously expressed autoantigens and the specificity of the T cell reactivity is not known. These autoantibodies are associated with distinct clinical phenotypes and some with distinct molecular pathways; e.g. sera from patients with anti-Jo-1 autoantibodies may activate the type I IFN system and these sera also contain high levels of B cell activating factor compared with other IIM subsets. The characterization of patients into subgroups based on autoantibody profiles seems to be a promising way to learn more about the specificities of the immune reactions. Careful phenotyping of infiltrating immune cells in muscle tissue before and after specific therapies and relating the molecular findings to clinical outcome measures may be another way to improve knowledge on specific immune mechanism in IIMs. Such information will be important for the development of new therapies. [ABSTRACT FROM AUTHOR]

The novel immunosuppressant sotrastaurin is a selective inhibitor of protein kinase C isoforms that are critical in signalling pathways downstream of the T cell receptor. Sotrastaurin inhibits nuclear factor ( NF)-κB, which directly promotes the transcription of forkhead box protein 3 ( Fox P3), the key regulator for the development and function of regulatory T cells (Tregs). Our center participated in a randomized trial comparing sotrastaurin ( n = 14) and the calcineurin inhibitor Neoral ( n = 7) in renal transplant recipients. We conducted ex vivo mixed lymphocyte reaction (MLR) and flow cytometry studies on these patient samples, as well as in vitro studies on samples of blood bank volunteers ( n = 38). Treg numbers remained stable after transplantation and correlated with higher trough levels of sotrastaurin ( r = 0·68, P = 0·03). A dose-dependent effect of sotrastaurin on alloresponsiveness was observed: the half maximal inhibitory concentration ( IC50) to inhibit alloactivated T cell proliferation was 45 ng/ml (90 nM). In contrast, Treg function was not affected by sotrastaurin: in the presence of in vitro-added sotrastaurin (50 ng/ml) Tregs suppressed the proliferation of alloactivated T effector cells at a 1:5 ratio by 35 versus 47% in the absence of the drug ( P = 0·33). Signal transducer and activator of transcription 5 ( STAT)-5 phosphorylation in Tregs remained intact after incubation with sotrastaurin. This potent Treg function was also found in cells of patients treated with sotrastaurin: Tregs inhibited the anti-donor response in MLR by 67% at month 6, which was comparable to pretransplantation (82%). Sotrastaurin is a potent inhibitor of alloreactivity in vitro, while it did not affect Treg function in patients after kidney transplantation. [ABSTRACT FROM AUTHOR]

Regulatory T cells [ Tregs; CD4+ CD25+ forkhead box protein 3 ( FoxP3+)] are subsets of T cells involved in the maintenance of peripheral self-tolerance by actively suppressing the activation and expansion of autoreactive T cells. Signalling through the interleukin-2 receptor ( IL-2 R) contributes to T cell tolerance by controlling three important aspects of regulatory T cell ( Treg) biology. CD25 is the α-chain of the IL-2 R that, in concert with the β-chain and γ-chain, constitutes the complete IL-2 R. CD25 contributes only to IL-2 binding affinity but not to the recruitment of signalling molecules. However, its importance in the development of a normal immune response is emphasized by the finding that a truncation mutant of CD25 results in an immunodeficiency in humans characterized by an increased susceptibility to viral, bacterial and fungal infections. In 1997, Sharfe et al. described an infant with severe bacterial, viral and fungal infections. Counts of autologous T lymphocytes were moderately low, T cells displayed a weak proliferative response to mitogens in vitro and the patient displayed no rejection of an allogeneic skin graft. However, unlike children with severe combined immunodeficiency ( SCID), besides not having circulating T cells, the patient also developed peripheral lymphocytic proliferation and autoimmune primary biliary cirrhosis. We present the first female Argentine patient with mutation in CD25 associated with chronic and severe inflammatory lung disease (follicular bronchiolitis with lymphocyte hyperplasia), eczema and infections. She has no expression of CD25 on CD4+ T cells and an extremely low amount of Tregs. The molecular study confirmed homozygous missense mutation in the alpha subunit of the IL-2 receptor ( CD25α R) (c. 122 a > c; p. Y41 S). [ABSTRACT FROM AUTHOR]

SLE is associated with a deficiency in cluster of differentiation 247 (CD247, also known as CD3 zeta chain), a component of the T-cell receptor (TCR)–CD3 complex. A comprehensive analysis showed that in more than half of SLE patients tested CD247 expression was either attenuated or absent. Recent evidence suggests that these variations in expression profiles may be due, at least in part, to polymorphisms in the CD247 gene. Aberrant CD247 transcript variants displaying either spliced exon 7 or short 3′-untranslated region have been detected in SLE T cells, and a recent genome-wide association study reported the existence of new CD247 single-nucleotide polymorphisms in SLE patients. Here, we review these unique and significant features of defective CD247 observed in SLE. [ABSTRACT FROM AUTHOR]