Imbalanced IL10/TGF-ß production by regulatory T-lymphocytes in patients with HTLV-1-associated myelopathy/ tropical spastic paraparesis.

BACKGROUND: Human T-cell lymphotropic virus type 1 (HTLV-1), also denominated Human T-cell leukemia virus-1, induces immune activation and secretion of proinflammatory cytokines, especially in individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Regulatory T lymphocytes (Tregs) may control of inflammation through the production of regulatory cytokines, including IL10 and TGF-ß. In this study we determined the frequencies of CD4 + and CD8 + Tregs in a HAM/TSP population, compared to asymptomatic carriers and uninfected individuals, as well as investigated the profiles of regulatory and inflammatory cytokines. METHODS: Asymptomatic HTLV-1 carriers and HAM/TSP patients were matched by sex and age. The frequencies of IL10- and/or TGF-ß-producing Tregs were quantified by flow cytometry. Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to quantify HTLV-1 proviral load and the mRNA expression of cytokines and cellular receptors in peripheral blood mononuclear cells. RESULTS: Total frequencies of CD4 + Tregs, as well as the IL10-producing CD4 + and CD8 + Treg subsets, were statistically higher in patients with HAM/TSP compared to asymptomatic HTLV-1-infected individuals. In addition, a positive correlation was found between the frequency of CD4 + IL10 + Tregs and proviral load in the HAM/TSP patients evaluated. A positive correlation was also observed between gene expression of proinflammatory versus regulatory cytokines only in HAM / TSP group. CONCLUSIONS: A higher frequencies of IL10-producing Tregs were identified in patients with HAM/TSP. Imbalanced production of IL10 in relation to TGF-ß may contribute to the increased inflammatory response characteristically seen in HAM/TSP patients.

[The role of microbiota and flavonoids in maintaining the balance of helper and regulatory T-lymphocytes associated with the intestinal immune barrier].

The gastrointestinal tract is a barrier, represented by dynamic and mutually regulating components (microbial, chemical, physical and immune) for the selective penetration of luminal contents into the internal environment. From the point of view of immunologists, even in a physiological condition, the epithelium of the intestinal wall is in a state of mild inflammation, which is explained by the constant invasion of antigens (food, microbial) and, in turn, the constant readiness of the immune system to respond. The purpose of this review was to analyze information about the formation of microbial and immunological barriers, immunological tolerance to microbiota and the possible role of flavonoids in this. Material and methods. The literature search was carried out using PubMed, ResearchGate, Elibrary databases mainly for the last 10 years, using the following keywords: flavonoid, gut microbiome/microbiota, Th17, Treg, RORγt, immunity, segmented filamentous bacteria. Results. During the immune response, a significant role in maintaining the intestinal barrier function is assigned to helper T lymphocytes type 17 (Th17). The intestinal microbiome is a key element in the formation of the immune barrier. Th17 differentiation in the intestine is fully triggered by commensals (apparently, the main role belongs to segmented filamentous bacteria) after weaning and the start of complementary feeding. Pro-inflammatory Th17 effectors in the gut are controlled by anti-inflammatory regulatory T-cells (Treg). In recent years, it has been established that despite the opposing functions of regulatory cells and effector Th17 cells, their differentiation is similar and is characterized by the expression of the common transcription factor RORγt. The main part of the peripheral regulatory lymphocytes of the intestine is a population that stably expresses not only FOXP3, but also RORγt. Flavonoids, which are plant secondary metabolites of the polyphenolic structure, are able to inhibit intracellular kinases and, as a result, influence the activation and implementation of effector functions of immunocompetent cells. Some flavonoids promote RORγt expression and appear to be able to reprogram the effector phenotype of Th17 cells, reducing their pathogenicity. Conclusion. Understanding the interactions between the microbiota, immune cells, and factors involved in their regulation, which are critical for the maintenance of tolerance, may facilitate progress in the prevention and therapeutic approaches to treat immunoinflammatory and autoimmune diseases.

Does molecular scarring in psoriasis exist? A review of the literature.

Plaque psoriasis is a chronic inflammatory dermatosis characterized by a tendency to recur in the same locations after discontinuation of treatment. The implementation of therapy with drugs targeting cytokines like interleukin (IL) 17A (IL-17A) and IL-23 has revolutionized the treatment of psoriasis and enabled the achievement of skin without lesions. However, despite the clinical resolution of psoriatic eruptions, cells that maintain the local memory of the disease remain in the dermis and epidermis, constituting a kind of molecular scar. The cells responsible for maintaining memory in the skin of patients and influencing the rapid relapse of the disease after the triggering factor are primarily tissue resident memory T cells (TRM), but it seems that regulatory T lymphocytes (Treg), dendritic cells (DC), and Langerhans cells (LC) may also play an important role in this process. We reviewed the literature to explain the concept of molecular scarring in psoriasis, and to assess the effect of various therapies on immune memory.

Local assessment of the immunohistochemical expression of Foxp3+ regulatory T lymphocytes in the different pathological forms associated with bovine paratuberculosis.

BACKGROUND: Mycobacterium avium subsp. paratuberculosis infected animals show a variety of granulomatous lesions, from focal forms with well-demarcated granulomas restricted to the gut-associated lymphoid tissue (GALT), that are seen in the initial phases or latency stages, to a diffuse granulomatous enteritis, with abundant (multibacillary) or scant (paucibacillary) bacteria, seen in clinical stages. Factors that determine the response to the infection, responsible for the occurrence of the different types of lesion, are still not fully determined. It has been seen that regulatory T cells (Treg) play an important role in various diseases where they act on the limitation of the immunopathology associated with the immune response. In the case of paratuberculosis (PTB) the role of Treg lymphocytes in the immunity against Map is far away to be completely understood; therefore, several studies addressing this subject have appeared recently. The aim of this work was to assess, by immunohistochemical methods, the presence of Foxp3+ T lymphocytes in intestinal samples with different types of lesions seen in cows with PTB. METHODS: Intestinal samples of twenty cows showing the different pathological forms of PTB were evaluated: uninfected controls (n = 5), focal lesions (n = 5), diffuse paucibacillary (n = 5) and diffuse multibacillary (n = 5) forms. Foxp3+ lymphocyte distribution was assessed by differential cell count in intestinal lamina propria (LP), gut-associated lymphoid tissue (GALT) and mesenteric lymph node (MLN). RESULTS: A significant increase in the number of Foxp3+ T cells was observed in infected animals with respect to control group, regardless of the type of lesion. However, when the different categories of lesion were analyzed independently, all individuals with PTB lesions showed an increase in the amount of Foxp3+ T lymphocytes compared to the control group but this increase was only significant in cows with focal lesions and, to a lesser extent, in animals with diffuse paucibacillary forms. The former showed the highest numbers, significantly different from those found in cows with diffuse lesions, where no differences were noted between the two forms. No specific distribution pattern was observed within the granulomatous lesions in any of the groups. CONCLUSIONS: The increase of Foxp3+ T cells in focal forms, that have been associated with latency or resistance to infection, suggest an anti-inflammatory action of these cells at these stages, helping to prevent exacerbation of the inflammatory response, as occurs in diffuse forms, responsible for the appearance of clinical signs.

Tag7-Mts1 Complex Activates Chemotaxis of Regulatory T Cells.

One of the basic features of immune system is the ability to sustain balance between activation and suppression of effector lymphocytes. In this process a key role belongs to the subpopulation of cells called regulatory T cells (Treg). Many cancer and autoimmune diseases are caused by malfunctions of Treg, and investigation of this subpopulation is important for development of new therapeutic approaches. In this study, we demonstrate that regulatory T cells can migrate along the concentration gradient of Tag7-Mts1 complex, and also they produce agents that induce blood cells migration.

Regulatory T lymphocyte infiltration in metastatic breast cancer-an independent prognostic factor that changes with tumor progression.

BACKGROUND: Patients diagnosed with metastatic breast cancer have poor outcome with a median survival of approximately 2 years. While novel therapeutic options are urgently needed, the great majority of breast cancer research has focused on the primary tumor and less is known about metastatic breast cancer and the prognostic impact of the metastatic tumor microenvironment. Here we investigate the immune landscape in unique clinical material. We explore how the immune landscape changes with metastatic progression and elucidate the prognostic role of immune cells infiltrating primary tumors and corresponding lymph node and more importantly distant metastases. METHODS: Immunohistochemical staining was performed on human breast cancer tissue microarrays from primary tumors (n = 231), lymph node metastases (n = 129), and distant metastases (n = 43). Infiltration levels of T lymphocytes (CD3+), regulatory T lymphocytes (Tregs, FOXP3+), macrophages (CD68+), and neutrophils (NE+) were assessed in primary tumors. T lymphocytes and Tregs were further investigated in lymph node and distant metastases. RESULTS: T lymphocyte and Treg infiltration were the most clinically important immune cell populations in primary tumors. Infiltration of T lymphocytes and Tregs in primary tumors correlated with proliferation (P = 0.007, P = 0.000) and estrogen receptor negativity (P = 0.046, P = 0.026). While both T lymphocyte and Treg infiltration had a negative correlation to luminal A subtype (P = 0.031, P = 0.000), only Treg infiltration correlated to luminal B (P = 0.034) and triple-negative subtype (P = 0.019). In primary tumors, infiltration of T lymphocytes was an independent prognostic factor for recurrence-free survival (HR = 1.77, CI = 1.01-3.13, P = 0.048), while Treg infiltration was an independent prognostic factor for breast cancer-specific survival (HR = 1.72, CI = 1.14-2.59, P = 0.01). Moreover, breast cancer patients with Treg infiltration in their distant metastases had poor post-recurrence survival (P = 0.039). Treg infiltration levels changed with metastatic tumor progression in 50% of the patients, but there was no significant trend toward neither lower nor higher infiltration. CONCLUSION: Treg infiltration could have clinical applicability as a prognostic biomarker, deciphering metastatic breast cancer patients with worse prognosis, and accordingly, could be a suitable immunotherapeutic target for patients with metastatic breast cancer. Importantly, half of the patients had changes in Treg infiltration during the course of metastatic progression emphasizing the need to characterize the metastatic immune landscape.

Humanized NOD/SCID/IL2rγnull mice exhibit functionally augmented human regulatory T cells associated with enzymatic up-regulation of H3K27me3 in comparison with humans.

Humanized non-obese diabetic/severe combined immunodeficiency/interleukin-2 receptor-γ-null (NOD/SCID/IL2rγnull ) [humanized (huNSG)] mice engrafted with human hematopoietic cells have been used for investigations of the human immune system. However, the epigenetic features of the human regulatory T (Treg ) cells of huNSG mice have not been studied. The objective of this study was to clarify the characteristics of human Treg cells in huNSG mice, especially in terms of the epigenetic aspects. We compared the populations, inhibitory molecule expression and suppressive capacity of human Treg cells in spleens harvested from the huNSG mice 120 days after the engraftment of human umbilical cord blood CD34+ cells with human peripheral blood mononuclear cells (PBMCs). Histone modifications and enhancer of zeste homolog 2 (Ezh2), an H3K27 methyltransferase, of human Treg cells were quantified in huNSG mice and human PBMCs. The effect of Ezh2 inhibitor on human Treg cells exposed to interleukin (IL)-6 was also compared between them. Human Treg cells in the spleens of huNSG mice showed an increased proportion among CD4+ T cells, higher expressions of forkhead box protein 3 (FoxP3), cytotoxic T lymphocyte antigen 4 (CTLA-4) and glucocorticoid-induced tumor necrosis factor-related protein (GITR), a higher production of IL-10 and enhanced suppressive capacity when compared with those in human PBMCs. H3K27me3 and Ezh2 were specifically up-regulated in human Treg cells of huNSG mice in comparison with those of human PBMCs. The decrease in Treg cells induced by IL-6 exposure was attenuated in huNSG mice when compared with human PBMCs, while the difference between them was cancelled by addition of Ezh2 inhibitor. In conclusion, huNSG mice exhibit functionally augmented human Treg cells owing to enzymatic up-regulation of H3K27me3.

Mesenchymal stromal cells induce regulatory T cells via epigenetic conversion of human conventional CD4 T cells in vitro.

Regulatory T cells (Treg) play a critical role in immune tolerance. The scarcity of Treg therapy clinical trials in humans has been largely due to the difficulty in obtaining sufficient Treg numbers. We performed a preclinical investigation on the potential of mesenchymal stromal cells (MSCs) to expand Treg in vitro to support future clinical trials. Human peripheral blood mononuclear cells from healthy donors were cocultured with allogeneic bone marrow-derived MSCs expanded under xenogeneic-free conditions. Our data show an increase in the counts and frequency of CD4+ CD25high Foxp3+ CD127low Treg cells (4- and 6-fold, respectively) after a 14-day coculture. However, natural Treg do not proliferate in coculture with MSCs. When purified conventional CD4 T cells (Tcon) are cocultured with MSCs, only cells that acquire a Treg-like phenotype proliferate. These MSC-induced Treg-like cells also resemble Treg functionally, since they suppress autologous Tcon proliferation. Importantly, the DNA methylation profile of MSC-induced Treg-like cells more closely resembles that of natural Treg than of Tcon, indicating that this population is stable. The expression of PD-1 is higher in Treg-like cells than in Tcon, whereas the frequency of PDL-1 increases in MSCs after coculture. TGF-ß levels are also significantly increased MSC cocultures. Overall, our data suggest that Treg enrichment by MSCs results from Tcon conversion into Treg-like cells, rather than to expansion of natural Treg, possibly through mechanisms involving TGF-ß and/or PD-1/PDL-1 expression. This MSC-induced Treg population closely resembles natural Treg in terms of phenotype, suppressive ability, and methylation profile.

Are chimeric antigen receptor T cells (CAR-T cells) the future in immunotherapy for autoimmune diseases?

OBJECTIVE: CAR-T cell therapy has revolutionized the treatment of oncological diseases, and potential uses in autoimmune diseases have recently been described. The review aims to integrate the available data on treatment with CAR-T cells, emphasizing autoimmune diseases, to determine therapeutic advances and their possible future clinical applicability in autoimmunity. MATERIALS AND METHODS: A search was performed in PubMed with the keywords "Chimeric Antigen Receptor" and "CART cell". The documents of interest were selected, and a critical review of the information was carried out. RESULTS: In the treatment of autoimmune diseases, in preclinical models, three different cellular strategies have been used, which include Chimeric antigen receptor T cells, Chimeric autoantibody receptor T cells, and Chimeric antigen receptor in regulatory T lymphocytes. All three types of therapy have been effective. The potential adverse effects within them, cytokine release syndrome, cellular toxicity and neurotoxicity must always be kept in mind. CONCLUSIONS: Although information in humans is not yet available, preclinical models of CAR-T cells in the treatment of autoimmune diseases show promising results, so that in the future, they may become a useful and effective therapy in the treatment of these pathologies.

Coaggregation of Asthma and Type 1 Diabetes in Children: A Narrative Review.

Asthma and type 1 diabetes mellitus (T1DM) are two of the most frequent chronic diseases in children, representing a model of the atopic and autoimmune diseases respectively. These two groups of disorders are mediated by different immunological pathways, T helper (Th)1 for diabetes and Th2 for asthma. For many years, these two groups were thought to be mutually exclusive according to the Th1/Th2 paradigm. In children, the incidence of both diseases is steadily increasing worldwide. In this narrative review, we report the evidence of the potential link between asthma and T1DM in childhood. We discuss which molecular mechanisms could be involved in the link between asthma and T1DM, such as genetic predisposition, cytokine patterns, and environmental influences. Cytokine profile of children with asthma and T1DM shows an activation of both Th1 and Th2 pathways, suggesting a complex genetic-epigenetic interaction. In conclusion, in children, the potential link between asthma and T1DM needs further investigation to improve the diagnostic and therapeutic approach to these patients. The aim of this review is to invite the pediatricians to consider the potential copresence of these two disorders in clinical practice.

Oxidized Low-Density Lipoprotein Receptor in Lymphocytes Prevents Atherosclerosis and Predicts Subclinical Disease.

BACKGROUND: Although the role of Th17 and regulatory T cells in the progression of atherosclerosis has been highlighted in recent years, their molecular mediators remain elusive. We aimed to evaluate the association between the CD69 receptor, a regulator of Th17/regulatory T cell immunity, and atherosclerosis development in animal models and in patients with subclinical disease. METHODS: Low-density lipoprotein receptor-deficient chimeric mice expressing or not expressing CD69 on either myeloid or lymphoid cells were subjected to a high fat diet. In vitro functional assays with human T cells were performed to decipher the mechanism of the observed phenotypes. Expression of CD69 and NR4A nuclear receptors was evaluated by reverse transcription-polymerase chain reaction in 305 male participants of the PESA study (Progression of Early Subclinical Atherosclerosis) with extensive (n=128) or focal (n=55) subclinical atherosclerosis and without disease (n=122). RESULTS: After a high fat diet, mice lacking CD69 on lymphoid cells developed large atheroma plaque along with an increased Th17/regulatory T cell ratio in blood. Oxidized low-density lipoprotein was shown to bind specifically and functionally to CD69 on human T lymphocytes, inhibiting the development of Th17 cells through the activation of NR4A nuclear receptors. Participants of the PESA study with evidence of subclinical atherosclerosis displayed a significant CD69 and NR4A1 mRNA downregulation in peripheral blood leukocytes compared with participants without disease. The expression of CD69 remained associated with the risk of subclinical atherosclerosis in an adjusted multivariable logistic regression model (odds ratio, 0.62; 95% CI, 0.40-0.94; P=0.006) after adjustment for traditional risk factors, the expression of NR4A1, the level of oxidized low-density lipoprotein, and the counts of different leucocyte subsets. CONCLUSIONS: CD69 depletion from the lymphoid compartment promotes a Th17/regulatory T cell imbalance and exacerbates the development of atherosclerosis. CD69 binding to oxidized low-density lipoprotein on T cells induces the expression of anti-inflammatory transcription factors. Data from a cohort of the PESA study with subclinical atherosclerosis indicate that CD69 expression in PBLs inversely correlates with the presence of disease. The expression of CD69 remained an independent predictor of subclinical atherosclerosis after adjustment for traditional risk factors.

Current advances and outlooks in immunotherapy for pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is an incurable cancer resistant to traditional treatments, although a limited number of early-stage patients can undergo radical resection. Immunotherapies for the treatment of haematological malignancies as well as solid tumours have been substantially improved over the past decades, and impressive results have been obtained in recent preclinical and clinical trials. However, PDAC is likely the exception because of its unique tumour microenvironment (TME). In this review, we summarize the characteristics of the PDAC TME and focus on the network of various tumour-infiltrating immune cells, outlining the current advances in PDAC immunotherapy and addressing the effect of the PDAC TME on immunotherapy. This review further explores the combinations of different therapies used to enhance antitumour efficacy or reverse immunodeficiencies and describes optimizable immunotherapeutic strategies for PDAC. The concordant combination of various treatments, such as targeting cancer cells and the stroma, reversing suppressive immune reactions and enhancing antitumour reactivity, may be the most promising approach for the treatment of PDAC. Traditional treatments, especially chemotherapy, may also be optimized for individual patients to remodel the immunosuppressive microenvironment for enhanced therapy.

Cancer immunotherapy-related adverse events: causes and challenges.

Despite the success and ongoing promise of monoclonal antibody-targeted immune checkpoint inhibitor immunotherapy of advanced malignancies, in particular, antibodies directed against CTLA-4 and PD-1/PD-L1, the development of immune-related adverse events (irAEs) remains a constraint of this type of therapy. Although rarely fatal, the occurrence of irAEs may necessitate discontinuation of immunotherapy, as well as administration of corticosteroids or other immunosuppressive therapies that may not only compromise efficacy but also predispose for development of opportunistic infection. Clearly, retention of efficacy of immune checkpoint-targeted therapies with concurrent attenuation of immune-mediated toxicity represents a formidable challenge. In this context, the current brief review examines mechanistic relationships between these events, as well as recent insights into immunopathogenesis, and strategies which may contribute to resolving this issue. These sections are preceded by brief overviews of the discovery and functions of CTLA-4 and PD-1, as well as the chronology of the development of immunotherapeutic monoclonal antibodies which target these immune checkpoint inhibitors.

Foxp3+ Regulatory T Cells Associated With CCL17/CCR4 Expression in Carcinomas of Dogs.

Regulatory T cells (Tregs) can be targeted in cancer immunotherapy. A previous study has shown that the chemokine CCL17 and the receptor CCR4 play a role in Treg recruitment in canine urothelial carcinoma. Here, we describe the association of tumor-infiltrating Tregs with CCL17/CCR4 expression in dogs with other carcinomas. In this study, we investigated 23 dogs with mammary carcinoma, 14 dogs with oral squamous cell carcinoma, 16 dogs with pulmonary adenocarcinoma, and 8 healthy control dogs. Immunohistochemistry showed that Foxp3+ Tregs and CCR4+ cells were increased in the tumor tissues of mammary carcinoma, squamous cell carcinoma, and pulmonary adenocarcinoma, when compared with the healthy tissues. The number of CCR4+ cells was associated with that of Foxp3+ Tregs. Double immunofluorescence labeling confirmed that most tumor-infiltrating Foxp3+ Tregs expressed CCR4. In vitro, canine carcinoma cell lines expressed CCL17 mRNA. Quantitative RT-PCR (reverse transcriptase-polymerase chain reaction) showed that CCL17 mRNA expression in canine carcinomas was increased approximately 10- to 25-fold relative to that of healthy tissues. These results suggest that the CCL17/CCR4 axis may drive Treg recruitment in a variety of canine carcinomas. CCR4 blockade may be a potential therapeutic option for tumor eradication through Treg depletion.

[Allergo-oncology: what allergologists and oncologists can learn from each other : Regulatory T cells in allergy and cancer]. / Allergoonkologie: was Allergologen und Onkologen voneinander lernen können : Regulatorische T­Zellen bei Allergie und Krebserkrankungen.

BACKGROUND: The immune system has substantial involvement in the pathophysiology of allergies and cancer. The complexity of the immune system is well balanced in health, in so-called immune homeostasis. In many diseases, as in allergies and cancer, this balance is disturbed. The tolerance to foreign but harmless substances, such as tree or grass pollen, is no longer sufficiently given in allergic patients. In cancer patients, the immune system is tolerant to harmful tumor cells. Thus, allergies and cancer show an opposing pattern in terms of immune tolerance. The group of regulatory T cells occupies a central position here. OBJECTIVE: This article deals with the function of regulatory T cells in detail. This group of immune cells and its interaction with other involved immune cells and messenger signals in the pathophysiology and treatment of allergies and cancer are presented. METHODS: A review article was compiled based on the pertinent literature. RESULTS: The regulatory T cells of cancer patients are a mechanism of the so-called tumor escape phenomenon to hide from the immune system. The tumor uses danger signals, e.g., the HMGB1 protein, to mediate tolerance to the immune system through these cells and thus avoid elimination. In allergic patients, these cells are underrepresented and can be induced by a specific immunotherapy, in order to achieve tolerance to the allergens and thus a causal treatment. CONCLUSION: Regulatory T cells play an important role in the pathogenesis of cancer and allergies, and thus represent a therapeutic target.

The role of regulatory T lymphocytes in immune control of MC-2 fibrosarcoma.

The role of T regulatory lymphocytes (Treg) particularly in cancer is well known. The goal of the present study was to determine the contribution of these lymphocytes in the regulation of anti-tumor immunity of CBA/HZgr mice against MC-2 fibrosarcoma (4th generation of methylcholanthrene induced tumor). The levels of T lymphocytes (CD4+, CD8+ and CD4+CD25+) were determined 8 and 20 days after tumor transplantation. Further, the role of CD4+CD25+ (Tregs) in tumor-host interaction was evaluated in vitro and in vivo by using specific monoclonal antibodies. We found that splenocytes of both control and Treg depleted tumor bearing mice strongly but differently inhibited growth of tumor cells in vitro. While splenocytes of untreated mice exhibited significant decrease of this activity (from 74.4% to 62.6% and 32.95%), the splenocytes of Treg depleted mice showed increase of this activity (from 79.5% to 84.3% and 86.2%) from day 6 to day 13 and day 21 after tumor grafting, respectively. Further, upon i.v. injecting specific monoclonal anti-Treg antibody tumor immediately prior to tumor cell intracutaneous transplantation, the tumor was rejected after initial growth. In treated mice, the incidence of Treg cells was very low initially, reaching normal values two weeks later. These animals were shown to be resistant to tumor transplantation four months later.

BAMBI regulates macrophages inducing the differentiation of Treg through the TGF-ß pathway in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by continuous flow limitation and the immune system including macrophages and regulatory T lymphocytes (Tregs) is involved in COPD pathogenesis. In our previous study, we investigated that TGF-ß/BAMBI pathway was associated with COPD by regulating the balance of Th17/Treg. However, the role of bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI), a pseudoreceptor of TGF-ß signalling pathway, in regulating the immune system of COPD patients has not been fully studied. Hence, we speculate that the pseudoreceptor BAMBI may play roles in the regulation of M2 macrophages to induce the differentiation of CD4+ naïve T cells into Tregs and influence the immune response in COPD. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy nonsmokers (n = 12), healthy smokers (n = 10) and COPD patients (n = 20). Naïve CD4+ T cells and monocytes-induced macrophages were used for coculture assays. The phenotypic characteristics of macrophages and Tregs were determined by flow cytometry. The expression levels of BAMBI and the TGF-ß/Smad pathway members in M2 macrophages were measured by a Western blot analysis. The monocyte-derived macrophages were stimulated with cigarette smoke extract (CSE, concentration of 0.02%) to simulate the smoking process in humans. pCMV-BAMBI was transfected into monocyte-derived M2 macrophages for subsequent co-culture assays and signalling pathway analysis. RESULTS: Our results showed that M2 macrophages could induce the differentiation of Tregs through the TGF-ß/Smad signalling pathway. In addition, monocyte-derived macrophages from COPD patients highly expressed BAMBI, and had a low capacity to induce Tregs differentiation. The expression of BAMBI and the forced expiratory volume in 1 second (FEV1%) were negatively correlated in COPD. Furthermore, overexpression of BAMBI promoted the conversion of M2 macrophages to M1 macrophages via the TGF-ß/Smad pathway. CONCLUSIONS: We demonstrated that BAMBI could promote the polarization process of M2 macrophages to M1 macrophages via the TGF-ß/Smad signalling pathway and that overexpression of BAMBI could decrease the ability of M2 macrophages to induce Treg differentiation. These findings may provide a potential mechanism by which blocking BAMBI could improve immune function to regulate COPD inflammatory conditions.

Chimeric antigen receptor-engineered regulatory T lymphocytes: promise for immunotherapy of autoimmune disease.

Regulatory T lymphocytes (Tregs) exist as natural ideal immunosuppressors in the immune system. Autologous or allogeneic Treg transfusion therapy has been carried out in animal models and humans as a new strategy for treating autoimmune disease. Recent studies have shown that Tregs can be engineered with chimeric antigen receptors to be antigen-specific, which are more effective than polyclonal Tregs with fewer target limitations and a lack of major histocompatibility complex restriction. This review describes the potential for applying chimeric antigen receptor-engineered regulatory T cells in autoimmune diseases.

The therapeutic potential of regulatory T lymphocytes in periodontitis: A systematic review.

This systematic review aimed to: (a) generate a descriptive synthesis of preclinical studies assessing the therapeutic potential of regulatory T lymphocytes (Tregs) to arrest periodontitis, (b) evaluate the methodological heterogeneity of the reviewed animal studies and (c) assess the risk of bias (RoB) of the included studies. The electronic search for animal studies included the MEDLINE, EMBASE, Web of Science and LILACS databases. In addition, a manual search assessed the high-ranked scientific journals in "periodontics/immunology" and the references listed in the included studies. There were no language, year or publication status restrictions. Two independent reviewers selected and extracted the data, and Cohen's Kappa coefficient was calculated to determine the inter-examiner agreement. The Systematic Review Center for Laboratory Animal Experimentation's (SYRCLE) tool was used to assess the RoB. A total of 21 of the 425 studies obtained from the database search were included. Treg function was mainly described in Porphyromonas gingivalis-induced periodontitis (57.1%) in mice (76.2%), where Treg suppression was strongly related to disease progression and Treg induction was strongly related to immuno-inflammatory response reduction. Of those 21 studies, eight included eight animal experiments using three distinct therapeutic approaches, including: P. gingivalis-driven immunization (n = 3), retinoic acid inoculation (n = 2) and anti-inflammatory molecules in polymeric carriers (n = 3), which could modulate the Treg activity through cytokine production (interleukin-10 and transforming growth factor-ß1), CC-chemokine- and CC-chemokine receptor-mediated chemoattraction (CCL22 and CCR4) or Th17-associated receptor activator of nuclear factor κB ligand (RANKL) downregulation. However, the studies with animal experiments did not specify the randomization sequences and housing conditions that were used, and therefore, 42.11% of the entries were rated as unclear RoB. Distinct therapeutic strategies involving Tregs could potentially suppress the immuno-inflammatory response and restore alveolar bone homeostasis during periodontitis. Nevertheless, important methodological variability, poor reporting of treatment effect estimates and unclear RoB suggest using caution when assessing the results of these studies.

Multifunctional nanocarriers for the treatment of periodontitis: Immunomodulatory, antimicrobial, and regenerative strategies.

Periodontitis is an inflammatory disease, in which the host immuno-inflammatory response against the dysbiotic subgingival biofilm leads to the breakdown of periodontal tissues. Most of the available treatments seem to be effective in the short-term; nevertheless, permanent periodical controls and patient compliance compromise long-term success. Different strategies have been proposed for the modulation of the host immune response as potential therapeutic tools to take a better care of most susceptible periodontitis patients, such as drug local delivery approaches. Though, maintaining an effective drug concentration for a prolonged period of time has not been achieved yet. In this context, advanced drug delivery strategies using biodegradable nanocarriers have been proposed to avoid toxicity and frequency-related problems of treatment. The versatility of distinct nanocarriers allows the improvement of their loading and release capabilities and could be potentially used for microbiological control, periodontal regeneration, and/or immunomodulation. In the present review, we revise and discuss the most frequent biodegradable nanocarrier strategies proposed for the treatment of periodontitis, including polylactic-co-glycolic acid (PLGA), chitosan, and silica-derived nanoparticles, and further suggest novel therapeutic strategies.