Increase of Th17 cells in peripheral blood of patients with chronic obstructive pulmonary disease

Granzyme B May Act as an Effector Molecule to Control the Inflammatory Process in COPD

Chronic obstructive pulmonary disease (COPD) is caused by smoking, but only a small proportion of smokers have disease severe enough to develop COPD. COPD is not always progressive. The question then arises as to what explains the different trajectories of COPD. The role of autoimmunity and regulatory T (Treg) cells in the pathogenesis of COPD is increasingly being recognized. Nine published studies on Treg cells in the lung tissue or bronchoalveolar lavage fluid have shown that smokers with COPD have fewer Treg cells than smokers without COPD or nonsmokers. Three studies showed a positive correlation between Treg cell count and FEV1%, suggesting an important role for Treg cells in COPD progression. Treg cells can regulate immunological responses via the granzyme B (GzmB) pathway. Immunohistochemical staining for GzmB in surgically resected lungs with centrilobular emphysema showed that the relationship between the amount of GzmB+ cells and FEV1% was comparable to that between Treg cell count and FEV1% in the COPD lung, suggesting that GzmB could be a functional marker for Treg cells. The volume fraction of GzmB+  cells in the small airways, the number of alveolar GzmB+ cells, and GzmB expression measured by enzyme-linked immunosorbent assay in the lung tissue of smokers were significantly correlated with FEV1%. These results suggest that the GzmB content in lung tissue may determine the progression of COPD by acting as an effector molecule to control inflammatory process. Interventions to augment GzmB-producing immunosuppressive cells in the early stages of COPD could help prevent or delay COPD progression.

Effects of Combustible Cigarettes and Electronic Nicotine Delivery Systems on the Development and Progression of Chronic Lung Inflammation in Mice

INTRODUCTION

Although detrimental effects of combustible cigarettes (CCs) on the progression of lung inflammatory diseases are well known, changes in electronic nicotine delivery systems (ENDS)-exposed lung-infiltrated immune cells are still unrevealed.

AIMS AND METHODS

The analysis of blood gas parameters, descriptive and quantitative histology of lung tissues, determination of serum cytokines, intracellular staining, and flow cytometry analysis of lung-infiltrated immune cells were used to determine the differences in the extent of lung injury and inflammation between mice from experimental (CC and ENDS-exposed animals) and control groups (Air-exposed mice).

RESULTS

Continuous exposition to either CCs or ENDS induced severe systemic inflammatory response, increased activation of NLRP3 inflammasome in neutrophils and macrophages and enhanced dendritic cell-dependent activation of Th1 and Th17 cells in the lungs. ENDS induced less severe immune response than CCs. Serum concentrations of inflammatory cytokines were significantly lower in the samples of ENDS-exposed mice. Compared to CCs, ENDS recruited lower number of circulating leukocytes in injured lungs and had less capacity to induce CD14/TLR2-dependent activation of NLRP3 inflammasome in lung-infiltrated neutrophils and macrophages. ENDS-primed dendritic cells had reduced capacity for the generation of Th1 and Th17 cell-driven lung inflammation. Accordingly, extensive immune cell-driven lung injury resulted in severe respiratory dysfunction in CCs-exposed mice, while ENDS caused moderate respiratory dysfunction in experimental animals.

CONCLUSIONS

Continuous exposition to either CCs or ENDS induced immune cell-driven lung damage in mice. ENDS triggered immune response, which was less potent than inflammatory response elicited by CCs and, therefore, caused less severe lung injury and inflammation.

IMPLICATIONS

This is the first study that compared the effects of CCs and ENDS on lung-infiltrated immune cells. Although both CCs and ENDS elicited systemic inflammatory response, immune cell-driven lung injury and inflammation were less severe in ENDS-exposed than in CC-exposed animals. Continuous exposition to ENDS-sourced aerosols was less harmful for respiratory function of experimental animals than CC-derived smoke.

Alterations in Peripheral Lymphocyte Subsets under Immunochemotherapy in Stage IV SCLC Patients: Th17 Cells as Potential Early Predictive Biomarker for Response

UICC stage IV small-cell lung cancer (SCLC) is a highly aggressive malignancy without curative treatment options. Several randomized trials have demonstrated improved survival rates through the addition of checkpoint inhibitors to first-line platin-based chemotherapy. Consequently, a combination of chemo- and immunotherapy has become standard palliative treatment. However, no reliable predictive biomarkers for treatment response exist. Neither PD-L1 expression nor tumor mutational burden have proven to be effective predictive biomarkers. In this study, we compared the cellular immune statuses of SCLC patients to a healthy control cohort and investigated changes in peripheral blood B, T, and NK lymphocytes, as well as several of their respective subsets, during treatment with immunochemotherapy (ICT) using flow cytometry. Our findings revealed a significant decrease in B cells, while T cells showed a trend to increase throughout ICT. Notably, high levels of exhausted CD4+ and CD8+ cells, alongside NK subsets, increased significantly during treatment. Furthermore, we correlated decreases/increases in subsets after two cycles of ICT with survival. Specifically, a decrease in Th17 cells indicated a better overall survival. Based on these findings, we suggest conducting further investigation into Th17 cells as a potential early predictive biomarkers for response in patients receiving palliative ICT for stage IV SCLC.

Using complete blood count, serum immunoglobulins G/A/M and complement C3/C4 levels to predict the risk of COPD acute exacerbation: 2-year follow-up in a single-center prospective cohort study

Autoimmunity is present in patients with stable chronic obstructive pulmonary disease (COPD), playing a role in indirect and direct ways. We aimed to explore whether autoimmunity could play a role in COPD exacerbations and construct autoimmunity-related prediction models. This prospective, longitudinal, observational cohort study enrolled 155 patients with acute COPD exacerbations (AECOPD) followed for at least two years. The laboratory parameters, including complete blood count, serum immunoglobulins G/A/M and complement C3/C4 levels, were collected at enrollment. We studied the demographic characteristics, clinical characteristics and laboratory parameters to identify independent risk factors and build predictive models. The results showed that lower lymphocyte count was associated with noninvasive ventilation (NIV) in patients with AECOPD (the odds ratio [OR] 0.25, the 95% confidence interval [CI]: 0.08-0.81, P = 0.02). Lymphocyte count performed well with an area under the curves (AUC) of 0.75 (P < 0.0001, sensitivity: 78.1%, specificity: 62.3%, cutoff value [Cov] ≤ 1.1). The C index, calibration plot, decision curve analysis (DCA) and bootstrap repetitions indicated that this clinical prediction model based on lymphocyte count for NIV in patients with AECOPD performed well. Having prior home oxygen therapy (OR: 2.82, 95% CI: 1.25-6.36, P = 0.013) and higher COPD Assessment Test (CAT) scores (OR: 1.14, 95% CI: 1.03-1.25, P = 0.011) were associated with the increased risk for respiratory failure. For predicting respiratory failure, CAT scores and home oxygen therapy combined had an AUC-ROC of 0.73 (P < 0.0001). This clinical prediction model based on lymphocyte count may help to assist in treatment decisions for NIV in patients with AECOPD. Lower complement C3 seems to be associated with worse outcomes in patients with AECOPD.

Astragaloside IV restores Th17/Treg balance via inhibiting CXCR4 to improve chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has a high fatality rate and poses a great threat to human health. Astragaloside IV (AS-IV) is proven to attenuate cigarette smoke (CS)-induced pulmonary inflammation, based on which this research focuses on the mechanism of AS-IV in COPD.

METHODS

To evaluate the effects of AS-IV, CD4+ T cells received different concentrations of AS-IV. CD4+ T cell viability, T helper 17 (Th17)/regulatory T (Treg) markers and CXCR4 expressions in CD4+ T cells or spleen/lung tissues were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay, quantitative real-time polymerase chain reaction and Western blot. The proportions of Treg and Th17 cells were assessed by flow cytometry. Enzyme-linked immune sorbent assay was employed to determine cytokine contents in serum and lung tissues.

RESULTS

AS-IV with concentration exceeding 40 µM inhibited CD4+ T cell viability. In vitro, AS-IV suppressed the expressions of CXCR4, retinoid-related orphan receptor γt (RORγt), and interleukin (IL)-17A as well as Th17 cells but promoted the expressions of forkhead box p3 (Foxp3) and IL-10 as well as Treg cells, while CXCR4 overexpression reversed the effects of AS-IV. In vivo, AS-IV alleviated COPD, and CS-induced Th17/Treg imbalance in mice and reduced CS-induced down-regulation of IL-10 in serum and lung tissues and Foxp3 and up-regulation of IL-1β, tumor necrosis factor alpha (TNF-α), IL-6, and IL-17A in serum and lung tissues and RORγt. AS-IV mitigated CS-induced CXCR4 up-regulation. Above effects of AS-IV on mice were offset by CXCR4 overexpression.

CONCLUSIONS

AS-IV restores Th17/Treg balance via impeding CXCR4 to ameliorate COPD.

DISCERN: deep single-cell expression reconstruction for improved cell clustering and cell subtype and state detection

BACKGROUND

Single-cell sequencing provides detailed insights into biological processes including cell differentiation and identity. While providing deep cell-specific information, the method suffers from technical constraints, most notably a limited number of expressed genes per cell, which leads to suboptimal clustering and cell type identification.

RESULTS

Here, we present DISCERN, a novel deep generative network that precisely reconstructs missing single-cell gene expression using a reference dataset. DISCERN outperforms competing algorithms in expression inference resulting in greatly improved cell clustering, cell type and activity detection, and insights into the cellular regulation of disease. We show that DISCERN is robust against differences between batches and is able to keep biological differences between batches, which is a common problem for imputation and batch correction algorithms. We use DISCERN to detect two unseen COVID-19-associated T cell types, cytotoxic CD4+ and CD8+ Tc2 T helper cells, with a potential role in adverse disease outcome. We utilize T cell fraction information of patient blood to classify mild or severe COVID-19 with an AUROC of 80% that can serve as a biomarker of disease stage. DISCERN can be easily integrated into existing single-cell sequencing workflow.

CONCLUSIONS

Thus, DISCERN is a flexible tool for reconstructing missing single-cell gene expression using a reference dataset and can easily be applied to a variety of data sets yielding novel insights, e.g., into disease mechanisms.

Modifiable risk factors linked to the development of rheumatoid arthritis: evidence, immunological mechanisms and prevention

Rheumatoid Arthritis (RA) is a common autoimmune disease that targets the synovial joints leading to arthritis. Although the etiology of RA remains largely unknown, it is clear that numerous modifiable risk factors confer increased risk to developing RA. Of these risk factors, cigarette smoking, nutrition, obesity, occupational exposures and periodontal disease all incrementally increase RA risk. However, the precise immunological mechanisms by which these risk factors lead to RA are not well understood. Basic and translational studies have provided key insights into the relationship between inflammation, antibody production and the influence in other key cellular events such as T cell polarization in RA risk. Improving our general understanding of the mechanisms which lead to RA will help identify targets for prevention trials, which are underway in at-risk populations. Herein, we review the modifiable risk factors that are linked to RA development and describe immune mechanisms that may be involved. We highlight the few studies that have sought to understand if modification of these risk factors reduces RA risk. Finally, we speculate that modification of risk factors may be an appealing avenue for prevention for some at-risk individuals, specifically those who prefer lifestyle interventions due to safety and economic reasons.

The lung-gut crosstalk in respiratory and inflammatory bowel disease

Both lung and gut belong to the common mucosal immune system (CMIS), with huge surface areas exposed to the external environment. They are the main defense organs against the invasion of pathogens and play a key role in innate and adaptive immunity. Recently, more and more evidence showed that stimulation of one organ can affect the other, as exemplified by intestinal complications during respiratory disease and vice versa, which is called lung-gut crosstalk. Intestinal microbiota plays an important role in respiratory and intestinal diseases. It is known that intestinal microbial imbalance is related to inflammatory bowel disease (IBD), this imbalance could impact the integrity of the intestinal epithelial barrier and leads to the persistence of inflammation, however, gut microbial disturbances have also been observed in respiratory diseases such as asthma, allergy, chronic obstructive pulmonary disease (COPD), and respiratory infection. It is not fully clarified how these disorders happened. In this review, we summarized the latest examples and possible mechanisms of lung-gut crosstalk in respiratory disease and IBD and discussed the strategy of shaping intestinal flora to treat respiratory diseases.

Phenotypic Profiling of Immune Cells and Their Mediators in Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is an inflammatory disorder and has been proposed to have an imbalance between pro-inflammatory and anti-inflammatory factors.

METHODS

This study was conducted on 41 participants {18 COPD patients (smokers, COPD S (n = 9); reformed smokers, COPD RS (n = 9)) and 23 controls (non-smokers, CNS (n = 14); smokers, CS (n = 9))}. Flow cytometry was used to identify circulatory immune cells and correlated with serum cytokines.

RESULTS

On comparison, significantly lower frequency of CD3+ T cells were observed in COPD S as compared to CNS (p < 0.01) and CS (p < 0.01); CD4+ T cells were lower in COPD S (p < 0.05), COPD RS (p < 0.05) and CNS (p < 0.01) as compared to CS. CD8+ T cells were elevated in COPD S as compared to CS (p < 0.05). Lower frequency of cDCs were observed in COPD S as compared to CS (p < 0.05) and COPD RS as compared to CNS (p < 0.01) and CS (p < 0.01). Lower frequency of pDCs were observed in COPD RS as compared to COPD S (p < 0.05), CNS (p < 0.05) and CS (p < 0.01). Lower frequency of Tregs was observed in COPD S as compared to CNS (p < 0.05) and CS (p < 0.05).

CONCLUSIONS

Characteristic changes observed indicate a significant impact of immune cells in the progression of the disease.

The Airway Microbiome-IL-17 Axis: a Critical Regulator of Chronic Inflammatory Disease

The respiratory tract is home to a diverse microbial community whose influence on local and systemic immune responses is only beginning to be appreciated. Increasing reports have linked changes in this microbiome to a range of pulmonary and extrapulmonary disorders, including asthma, chronic obstructive pulmonary disease and rheumatoid arthritis. Central to many of these findings is the role of IL-17-type immunity as an important driver of inflammation. Despite the crucial role played by IL-17-mediated immune responses in protection against infection, overt Th17 cell responses have been implicated in the pathogenesis of several chronic inflammatory diseases. However, our knowledge of the influence of bacteria that commonly colonise the respiratory tract on IL-17-driven inflammatory responses remains sparse. In this article, we review the current knowledge on the role of specific members of the airway microbiota in the modulation of IL-17-type immunity and discuss how this line of research may support the testing of susceptible individuals and targeting of inflammation at its earliest stages in the hope of preventing the development of chronic disease.

Autoimmune pre-disease

Approximately 5% of the world-wide population is affected by autoimmune diseases. Overall, autoimmune diseases are still difficult to treat, impose a high burden on patients, and have a significant economic impact. Like other complex diseases, e.g., cancer, autoimmune diseases develop over several years. Decisive steps in the development of autoimmune diseases are (i) the development of autoantigen-specific lymphocytes and (often) autoantibodies and (ii) potentially clinical disease manifestation at a later stage. However, not all healthy individuals with autoantibodies develop disease manifestations. Identifying autoantibody-positive healthy individuals and monitoring and inhibiting their switch to inflammatory autoimmune disease conditions are currently in their infancy. The switch from harmless to inflammatory autoantigen-specific T and B-cell and autoantibody responses seems to be the hallmark for the decisive factor in inflammatory autoimmune disease conditions. Accordingly, biomarkers allowing us to predict this progression would have a significant impact. Several factors, such as genetics and the environment, especially diet, smoking, exposure to pollutants, infections, stress, and shift work, might influence the progression from harmless to inflammatory autoimmune conditions. To inspire research directed at defining and ultimately targeting autoimmune predisease, here, we review published evidence underlying the progression from health to autoimmune predisease and ultimately to clinically manifest inflammatory autoimmune disease, addressing the following 3 questions: (i) what is the current status, (ii) what is missing, (iii) and what are the future perspectives for defining and modulating autoimmune predisease.

Caveolin-1 Promotes the Imbalance of Th17/Treg in Chronic Obstructive Pulmonary Disease by Regulating Hsp70 Expression

Objective

To investigate whether the expression of Hsp70 is associated with Cav-1 in promoting the imbalance of Th17/Treg cells in COPD.

Methods

The plasma Cav-1, Hsp70 expression were quantified by enzyme-linked immunosorbent assay (ELISA). The frequencies of circulating Th17, Treg cells and Th17/Treg ratio were determined by flow cytometry. Peripheral blood mononuclear cells (PBMCs) from subjects were transfected with Cav-1 or control plasmids and Hsp70 plasmid.

Results

We found that Cav-1 expression was lower but the levels of Hsp70 and Th17 cells were higher in COPD than in healthy control (HC). Hsp70 expressions were positively correlated with Cav-1 levels, Th17 cells, and Th17/Treg ratio in COPD but not in HC. Cav-1 over-expression resulted in an increase in Hsp70 and Th17 levels. Suppressing Hsp70 expressing by small interfering RNA (siRNA), the decline of Th17 frequency was observed in Cav-1-overexpressed PBMCs.

Conclusion

Collectively, our results illuminate that Cav-1 contributes to the imbalance of Th17/Treg through potentially regulating Hsp70 expression.

Modulation of mouse laryngeal inflammatory and immune cell responses by low and high doses of mainstream cigarette smoke

Cigarette smoking is a major risk factor for laryngeal diseases. Despite well-documented cigarette smoke (CS) induced laryngeal histopathological changes, the underlying immunopathological mechanisms remain largely unexplored. The goal of this study was to evaluate inflammatory and immune cell responses in a CS-exposed larynx. Specifically, we used a 4-week subacute whole-body CS inhalation mouse model to assess these responses in the laryngeal mucosa upon exposure to low (LD; 1 h/day) and high dose (HD; 4 h/day) CS. Laryngeal tissues were harvested and evaluated using a 254-plex NanoString inflammation panel and neutrophil/macrophage/T-cell immunohistochemistry (IHC). NanoString global and differential gene expression analysis revealed a unique expression profile only in the HD group, with 26 significant differentially expressed genes (DEGs). StringDB KEGG pathway enrichment analysis revealed the involvement of these DEGs with pro-inflammatory pathways including TNF/TNFα and IL-17. Furthermore, inflammatory responses remained inhibited in conjunction with predicted activated states of anti-inflammatory regulators like PPARγ and NFE2L2 upon Ingenuity Pathway Analysis (IPA). Subglottic T-cell levels remained significantly inhibited as corroborated by IPA predictions. Overall, our key findings are consistent with HD exposures being anti-inflammatory and immunosuppressive. Furthermore, the identification of important regulatory genes and enriched pathways may help improve clinical interventions for CS-induced laryngeal diseases.

Highway to heal: Influence of altered extracellular matrix on infiltrating immune cells during acute and chronic lung diseases

Environmental insults including respiratory infections, in combination with genetic predisposition, may lead to lung diseases such as chronic obstructive pulmonary disease, lung fibrosis, asthma, and acute respiratory distress syndrome. Common characteristics of these diseases are infiltration and activation of inflammatory cells and abnormal extracellular matrix (ECM) turnover, leading to tissue damage and impairments in lung function. The ECM provides three-dimensional (3D) architectural support to the lung and crucial biochemical and biophysical cues to the cells, directing cellular processes. As immune cells travel to reach any site of injury, they encounter the composition and various mechanical features of the ECM. Emerging evidence demonstrates the crucial role played by the local environment in recruiting immune cells and their function in lung diseases. Moreover, recent developments in the field have elucidated considerable differences in responses of immune cells in two-dimensional versus 3D modeling systems. Examining the effect of individual parameters of the ECM to study their effect independently and collectively in a 3D microenvironment will help in better understanding disease pathobiology. In this article, we discuss the importance of investigating cellular migration and recent advances in this field. Moreover, we summarize changes in the ECM in lung diseases and the potential impacts on infiltrating immune cell migration in these diseases. There has been compelling progress in this field that encourages further developments, such as advanced in vitro 3D modeling using native ECM-based models, patient-derived materials, and bioprinting. We conclude with an overview of these state-of-the-art methodologies, followed by a discussion on developing novel and innovative models and the practical challenges envisaged in implementing and utilizing these systems.

Immunological Insights into Cigarette Smoking-Induced Cardiovascular Disease Risk

Smoking is one of the most prominent addictions of the modern world, and one of the leading preventable causes of death worldwide. Although the number of tobacco smokers is believed to be at a historic low, electronic cigarette use has been on a dramatic rise over the past decades. Used as a replacement for cigarette smoking, electronic cigarettes were thought to reduce the negative effects of burning tobacco. Nonetheless, the delivery of nicotine by electronic cigarettes, the most prominent component of cigarette smoke (CS) is still delivering the same negative outcomes, albeit to a lesser extent than CS. Smoking has been shown to affect both the structural and functional aspects of major organs, including the lungs and vasculature. Although the deleterious effects of smoking on these organs individually is well-known, it is likely that the adverse effects of smoking on these organs will have long-lasting effects on the cardiovascular system. In addition, smoking has been shown to play an independent role in the homeostasis of the immune system, leading to major sequela. Both the adaptive and the innate immune system have been explored regarding CS and have been demonstrated to be altered in a way that promotes inflammatory signals, leading to an increase in autoimmune diseases, inflammatory diseases, and cancer. Although the mechanism of action of CS has not been fully understood, disease pathways have been explored in both branches of the immune system. The pathophysiologically altered immune system during smoking and its correlation with cardiovascular diseases is not fully understood. Here we highlight some of the important pathological mechanisms that involve cigarette smoking and its many components on cardiovascular disease and the immune systems in order to have a better understanding of the mechanisms at play.

The mechanistic role of neutrophil lymphocyte ratio perturbations in the leading non communicable lifestyle diseases

Inflammation plays a critical role in the development and progression of chronic diseases like type 2 diabetes mellitus, coronary artery disease, and chronic obstructive pulmonary disease. Inflammatory responses are indispensable for pathogen control and tissue repair, but they also cause collateral damage. A chronically activated immune system and the resultant immune dysregulation mediated inflammatory surge may cause multiple negative effects, requiring tight regulation and dampening of the immune response to minimize host injury.  While chronic diseases are characterized by systemic inflammation, the mechanistic relationship of neutrophils and lymphocytes to inflammation and its correlation with the clinical outcomes is yet to be elucidated. The neutrophil to lymphocyte ratio (NLR) is an easy-to-measure laboratory marker used to assess systemic inflammation. Understanding the mechanisms of NLR perturbations in chronic diseases is crucial for risk stratification, early intervention, and finding novel therapeutic targets. We investigated the correlation between NLR and prevalent chronic conditions as a measure of systemic inflammation. In addition to predicting the risk of impending chronic conditions, NLR may also provide insight into their progression. This review summarizes the mechanisms of NLR perturbations at cellular and molecular levels, and the key inflammatory signaling pathways involved in the progression of chronic diseases. We have also explored preclinical studies investigating these pathways and the effect of quelling inflammation in chronic disease as reported by a few in vitro, in vivo studies, and clinical trials.

Sex-biased adaptive immune regulation in cancer development and therapy

The cancer research field is finally starting to unravel the mystery behind why males have a higher incidence and mortality rate than females for nearly all cancer types of the non-reproductive systems. Here, we explain how sex - specifically sex chromosomes and sex hormones - drives differential adaptive immunity across immune-related disease states including cancer, and why males are consequently more predisposed to tumor development. We highlight emerging data on the roles of cell-intrinsic androgen receptors in driving CD8⁺ T cell dysfunction or exhaustion in the tumor microenvironment and summarize ongoing clinical efforts to determine the impact of androgen blockade on cancer immunotherapy. Finally, we outline a framework for future research in cancer biology and immuno-oncology, underscoring the importance of a holistic research approach to understanding the mechanisms of sex dimorphisms in cancer, so sex will be considered as an imperative factor for guiding treatment decisions in the future.

Immunophenotype in acute exacerbation of chronic obstructive pulmonary disease: a cross-sectional study

Background

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, and the immune inflammatory response is thought to play an important role in pathogenesis. However, the immunophenotype of patients with COPD is unknown. Herein, we evaluated the immunophenotype of patients with acute exacerbation of COPD (AECOPD).

Methods

A cross-sectional study was conducted in West China Hospital from September 2018 to October 2019. The proportion of CD4 + T lymphocyte subtypes (Th1, Th2, Th17 and Treg) and levels of serum cytokines in the peripheral blood of patients with AECOPD, stable COPD (SCOPD), healthy smokers (HSs)and healthy controls (HCs) were evaluated.

Results

A total of 15 HCs, 19 HSs, 42 patients with SCOPD, and 55 patients with AECOPD were included. Compared to patients with SCOPD, Th1 cells, Th17 cells, Treg cell ratio, Th1/Th2 cell ratio, and the levels of C-reactive protein, interleukin (IL)-6, and IL-10 were significantly increased in patients with AECOPD (P < 0.001), while the proportion of Th2 cells was significantly reduced (P < 0.01). The proportion of Th17 cells was positively correlated with COPD Assessment Test score (r = 0.266, P = 0.009), modified Medical Research Council dyspnea score (r = 0.858, P < 0.0001), and Th1 cell ratio (r = 0.403, P < 0.0001) and negatively correlated with forced vital capacity (r = − 0.367, P = 0.009) and proportion of Th2 cells (r = − 0.655, P < 0.0001).

Conclusions

The immunophenotype of patients with AECOPD shows abnormal activation of Th1, Th17, and Treg cells. There is a correlation between the proportion of Th17 cells and the severity of COPD; therefore, this may represent a novel index for the evaluation of COPD severity.

Trial registration: China Clinical Trials Registry, ChiCTR1800018452, registered 19 September 2018, https://www.chictr.org.cn/index.aspx.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02058-x.

Implications of the Immune Landscape in COPD and Lung Cancer: Smoking Versus Other Causes

Cigarette smoking is reported in about one third of adults worldwide. A strong relationship between cigarette smoke exposure and chronic obstructive pulmonary disease (COPD) as well as lung cancer has been proven. However, about 15% of lung cancer cases, and between one fourth and one third of COPD cases, occur in never-smokers. The effects of cigarette smoke on the innate as well as the adaptive immune system have been widely investigated. It is assumed that certain immunologic features contribute to lung cancer and COPD development in the absence of smoking as the major risk factor. In this article, we review different immunological aspects of lung cancer and COPD with a special focus on non-smoking related risk factors.

Effects of Vitamin D on Respiratory Function and Immune Status for Patients with Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis

Background

Many studies have demonstrated that vitamin D has clinical benefits when used to treat patients with chronic obstructive pulmonary disease (COPD). However, most of these studies have insufficient samples or inconsistent results. The aim of this meta-analysis was to evaluate the effects of vitamin D therapy in patients with COPD.

Methods

We performed a comprehensive retrieval in the following electronic databases: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data, and Chinese Scientific Journals Database (VIP). Two trained reviewers identified relevant studies, extracted data information, and then assessed the methodical quality by the Cochrane risk of bias assessment tool, independently. Then, the meta-analyses were conducted by RevMan 5.4, binary variables were represented by risks ratio (RR), and continuous variables were represented by mean difference (MD) or standardized mean difference (SMD) to assess the efficacy of vitamin D therapy in patients with COPD. Then, publication bias assessment was conducted by funnel plot analysis. Finally, the quality of evidence was assessed by the GRADE system.

Results

A total of 15 articles involving 1598 participants were included in this study. The overall results showed a statistical significance of vitamin D therapy in patients with COPD which can significantly improve forced expiratory volume in 1 second (FEV1) (MD: 5.69, 95% CI: 5.01-6.38,P < 0.00001,I2 = 51%) and FEV1/FVC (SMD:0.49, 95% CI: 0.39-0.60,P < 0.00001,I2 = 84%); and serum 25 (OH)D (SMD:1.21, 95% CI:1.07-1.34,P < 0.00001,I2 = 98%) also increase CD3+ Tcells (MD: 6.67, 95% CI: 5.34-8.00,P < 0.00001,I2 = 78%) and CD4+ T cells (MD: 6.00, 95% CI: 5.01-7.00,P < 0.00001,I2 = 65%); and T lymphocyte CD4+/CD8+ ratio (MD: 0.41, 95% CI: 0.20-0.61,P = 0.0001,I2 = 95%) obviously decrease CD8+ Tcells(SMD: -0.83, 95% CI: -1.05- -0.06,P < 0.00001,I2 = 82%), the times of acute exacerbation (RR: 0.40, 95% CI: 0.28-0.59,P < 0.00001,I2 = 0%), and COPD assessment test (CAT) score (MD: -3.77, 95% CI: -5.86 - -1.68,P = 0.0004,I2 = 79%).

Conclusions

Our analysis indicated that vitamin D used in patients with COPD could improve the lung function (FEV1 and FEV1/FVC), the serum 25(OH)D, CD3+ T cells, CD4 + T cells, and T lymphocyte CD4+/CD8+ ratio and reduce CD8+ T cells, acute exacerbation, and CAT scores.

Cigarette smoke-induced extracellular vesicles from dendritic cells alter T-cell activation and HIV replication

Despite decreased rates of tobacco smoking in many areas, cigarette smoking remains a major contributor to many health problems. Cigarette smoking can reduce immune system functioning while concurrently increasing inflammation. Dendritic cells in the lung exposed to cigarette smoke become stimulated and go on to activate T-cells. Extracellular vesicles (EVs) are nano-sized particles released by cells. They participate in intercellular communication by transferring functional proteins and nucleic acids to recipient cells and have been implicated in immune responses. For example, they can display MHC-peptide complexes to activate T-cells. In the current study, we sought to understand the role of cigarette smoke extract (CSE) on dendritic cell-derived EVs and their capacity to activate and differentiate T-cells. Primary human dendritic cells (iDCs) were exposed to CSE and EVs were separated and characterized. We exposed autologous primary CD4 + T-cells to iDC-EVs and observed T helper cell populations skewing towards Th1 and Th17 phenotypes. As HIV + individuals are disproportionately likely to be current smokers, we also examined the effects of iDC-EVs on acutely infected T-cells as well as on a cell model of HIV latency (ACH-2). We found that in most cases, iDC-CSE EVs tended to reduce p24 release from the acutely infected primary T-cells, albeit with great variability. We did not observe large effects of iDC-EVs or direct CSE exposure on p24 release from the ACH-2 cell line. Together, these data suggest that iDC-CSE EVs have the capacity to modulate the immune responses, in part by pushing T-cells towards Th1 and Th17 phenotypes.

The functions of CD4 T-helper lymphocytes in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) has been increasingly accounted for global morbidity and mortality worldwide. Although it is partially reversible, the obstructive ventilatory schema of COPD often causes chronic inflammation that primarily affects peripheral airways, pulmonary parenchyma, and the development of lung lymphoid follicles. Among various T-helper (Th) cell types associated with COPD, Th1, Th2 and Th17 cell numbers are increased in COPD patients, whereas Treg cell number is reduced. Here, we reviewed recent advance in understanding the roles of Th1/Th2 and Th17/Treg in the pathogenesis of COPD and discussed the potential underlying mechanism.

Th17/Treg Imbalance in Chronic Obstructive Pulmonary Disease: Clinical and Experimental Evidence

The imbalance between pro- and anti-inflammatory immune responses mediated by Th17 and Treg cells is deeply involved in the development and progression of inflammation in chronic obstructive pulmonary disease (COPD). Several clinical and experimental studies have described the Th17/Treg imbalance in COPD progression. Due to its importance, many studies have also evaluated the effect of different treatments targeting Th17/Treg cells. However, discrepant results have been observed among different lung compartments, different COPD stages or local and systemic markers. Thus, the data must be carefully examined. In this context, this review explores and summarizes the recent outcomes of Th17/Treg imbalance in COPD development and progression in clinical, experimental and in vitro studies.

The influence of early-life microbial exposures on long-term respiratory health

Host-microbiome interactions exert a profound influence on human physiology and health outcomes. In particular, certain characteristics of commensal microbiota during a critical period in early life are essential for the establishment of immune tone and metabolic control. An increasing body of evidence suggests that early life exposures that disrupt these interactions can substantially influence life-long risks for respiratory disease. Here, we explore how such early life exposures, including antibiotic exposure, maternal diet, preterm birth, mode of delivery, breastfeeding, and environmental variables shape the infant microbiome, and the mechanisms by such changes can in turn impact respiratory health.

E-Cadherin: An Important Functional Molecule at Respiratory Barrier Between Defence and Dysfunction

While breathing, many microorganisms, harmful environmental particles, allergens, and environmental pollutants enter the human airways. The human respiratory tract is lined with epithelial cells that act as a functional barrier to these harmful factors and provide homeostasis between external and internal environment. Intercellular epithelial junctional proteins play a role in the formation of the barrier. E-cadherin is a calcium-dependent adhesion molecule and one of the most important molecules involved in intercellular epithelial barier formation. E-cadherin is not only physical barrier element but also regulates cell proliferation, differentiation and the immune response to environmental noxious agents through various transcription factors. In this study, we aimed to review the role of E-cadherin in the formation of airway epithelial barier, its status as a result of exposure to various environmental triggers, and respiratory diseases associated with its dysfunction. Moreover, the situations in which its abnormal activation can be noxious would be discussed.

Extract From Tetrastigma hemsleyanum Leaf Alleviates Pseudomonas aeruginosa Lung Infection: Network Pharmacology Analysis and Experimental Evidence

Tetrastigma hemsleyanum Diels & Gilg (T. hemsleyanum) has attracted much attention due to its ability on pneumonia, bronchitis, and immune-related diseases, while its functional components and underlying mechanism of action on pneumonia have not been fully elucidated. Herein, we used a systematic network pharmacology approach to explore the action mechanism of T. hemsleyanum leaf in the treatment of pneumonia. In this study, the results of network pharmacology demonstrated that there were 34 active components and 80 drug-disease targets in T. hemsleyanum leaf, which were strongly in connection with signal transduction, inflammatory response, and the oxidation-reduction process. Subsequently, a mouse model of pneumonia induced by Pseudomonas aeruginosa (P. aeruginosa) was established to validate the predicted results of network pharmacology. In the animal experiments, aqueous extract of T. hemsleyanum leaf (EFT) significantly attenuated the histopathological changes of lung tissue in P. aeruginosa-induced mice and reduced the number of bacterial colonies in BALFs by 96.84% (p < 0.01). Moreover, EFT treatment suppressed the increase of pro-inflammatory cytokines IL-17, IL-6, and TNF-α in lung tissues triggered by P. aeruginosa, which led to the increase of Th17 cells (p < 0.05). High concentration of EFT treatment (2.0 g/kg) obviously increased the anti-inflammatory cytokine levels, accompanied by the enhancement of Treg proportion in a dose-dependent manner and a notable reversal of transcription factor RORγt expression. These findings demonstrated that network pharmacology was a useful tool for TCM research, and the anti-inflammatory effect of EFT was achieved by maintaining Th17/Treg immune homeostasis and thereby suppressing the inflammatory immune response.

Emerging Biological Functions of IL-17A: A New Target in Chronic Obstructive Pulmonary Disease?

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease that causes high rates of disability and mortality worldwide because of severe progressive and irreversible symptoms. During the period of COPD initiation and progression, the immune system triggers the activation of various immune cells, including Regulatory T cells (Tregs), dendritic cells (DCs) and Th17 cells, and also the release of many different cytokines and chemokines, such as IL-17A and TGF-β. In recent years, studies have focused on the role of IL-17A in chronic inflammation process, which was found to play a highly critical role in facilitating COPD. Specially, IL-17A and its downstream regulators are potential therapeutic targets for COPD. We mainly focused on the possibility of IL-17A signaling pathways that involved in the progression of COPD; for instance, how IL-17A promotes airway remodeling in COPD? How IL-17A facilitates neutrophil inflammation in COPD? How IL-17A induces the expression of TSLP to promote the progression of COPD? Whether the mature DCs and Tregs participate in this process and how they cooperate with IL-17A to accelerate the development of COPD? And above associated studies could benefit clinical application of therapeutic targets of the disease. Moreover, four novel efficient therapies targeting IL-17A and other molecules for COPD are also concluded, such as Bufei Yishen formula (BYF), a Traditional Chinese Medicine (TCM), and curcumin, a natural polyphenol extracted from the root of Curcuma longa.

N-Acetylcysteine Improves Inflammatory Response in COPD Patients by Regulating Th17/Treg Balance through Hypoxia Inducible Factor-1α Pathway

Introduction

This study was aimed to investigate the effects of N-acetylcysteine (NAC) on chronic obstructive pulmonary disease (COPD) and the change of Th17/Treg cytokine imbalance. Material and Methods. A total of 121 patients with stable COPD at the stage of C or D were consecutively enrolled and randomly divided into 2 groups. Patients in the treatment group received NAC granules (0.2 g × 10 bags, 0.4 g each time, 3 times/d) for half a year. The control group was treated with the same amount of placebo therapy. The peripheral blood of the patient was collected and the cytokine, T lymphocyte subsets were detected.

Results

We found the oral administration of NAC could regulate Th17/Treg balance to resist inflammation in COPD patients. Serum testing showed that the proportion of Treg in CD4+ T cells has increased and the Th17/Treg ratio has decreased during the NAC treatment. In vitro studies, we found that NAC regulated Th17/Treg balance through Hypoxia Inducible Factor-1α pathway.

Conclusions

Our result could provide new diagnosis and treatment for elderly patients with COPD from the perspective of immunity ideas.

T-Helper 17 Cell/Regulatory T-Cell Imbalance in COPD Combined with T2DM Patients

Background

Chronic obstructive pulmonary disease (COPD) is often combined with type 2 diabetes mellitus (T2DM) in clinical, and with poor prognosis. In recent years, research shows that inflammation is a common characteristic of COPD and T2DM. T-helper 17 cell (Th17)/regulatory T-cell (Treg) balance controls inflammation and may be important in the pathogenesis of COPD combined with T2DM patients. This study investigated the characteristics of Th17, Treg and related inflammatory factors in COPD combined with T2DM patients and the potential mechanism.

Methods

Application of flow cytometry technology, real-time fluorescent quantitative PCR and ELISA to detect the changes in peripheral blood of Th17 and Treg number and the expression of key transcription factors and related cytokines in COPD combined T2DM patients were performed.

Results

Patients with COPD combined with T2DM revealed significant increase in peripheral Th17, Th17 related cytokines (IL-17A, IL-17F, IL-21, IL-23, IL-6) and transcription factor (RORγt) levels and significant decrease in Treg, Treg-related cytokines (IL-10, TGFβ1) and transcription factor (Foxp3) as compared with patients with COPD, T2DM and healthy controls.

Conclusion

Th17/Treg functional imbalance exists in patients with COPD combined with T2DM, indicating a potential role of Th17/Treg imbalance in the formation and progression of COPD combined with T2DM.

Electroacupuncture inhibits IL-17/IL-17R and post-receptor MAPK signaling pathways in a rat model of chronic obstructive pulmonary disease

OBJECTIVE

Interleukin (IL)-17, as a T-helper 17 cell (Th17) cytokine, plays a key role in chronic obstructive pulmonary disease (COPD) pathophysiology including chronic inflammation and airway obstruction, which lead to decreased pulmonary function. The aim of this study was to investigate the effect of acupuncture on IL-17, its receptor (IL-17R) and the mitogen-activated protein kinase (MAPK) signaling pathway, in a rat model of COPD.

METHODS

The COPD model was induced in Sprague Dawley rats by exposure to cigarette smoke for 12 weeks. The model rats were treated with electroacupuncture (EA) at BL13 and ST36. The lung function and histology of the rats were observed. IL-17, tumor necrosis factor (TNF)-α, and IL-10 were detected by enzyme-linked immunosorbent assay (ELISA) in bronchoalveolar lavage fluid (BALF) and in plasma. The leukocytes and macrophages in the BALF were counted. The expression levels of IL-17R were assayed in lung tissue by real-time polymerase chain reaction (PCR), western blotting, and immunohistochemistry. MAPK signaling pathway molecules including c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK)1/2 and p38, and their phosphorylated forms, were observed in the lung by western blotting.

RESULTS

Compared with the control group rats, lung function decreased and there was a severe inflammatory infiltration of the pulmonary parenchyma in the COPD rats. EA effectively improved lung function and alleviated the inflammatory infiltration in the lungs of COPD rats. EA also reversed the elevated total leukocyte and macrophage counts, the high levels of IL-17 and TNF-α, and the low IL-10 content in COPD rats. Meanwhile, EA downregulated the increased mRNA and protein expression of IL-17R, and significantly inhibited the elevated levels of phosphorylated JNK, ERK1/2, and p38 in the lungs of COPD rats.

CONCLUSION

Our results suggest that the protective effects of acupuncture therapy on the lungs of COPD rats are likely related to inhibition of IL-17/IL-17R and the post-receptor MAPK signaling pathways.

The elastin peptide VGVAPG increases CD4+ T-cell IL-4 production in patients with chronic obstructive pulmonary disease

Background

In chronic obstructive pulmonary disease (COPD), lung-infiltrating inflammatory cells secrete proteases and participate in elastin breakdown and genesis of elastin-derived peptides (EP). In the present study, we hypothesized that the pattern of T lymphocytes cytokine expression may be modulated by EP in COPD patients.

Methods

CD4⁺ and CD8⁺ T-cells, sorted from peripheral blood mononuclear cells (PBMC) collected from COPD patients (n = 29) and controls (n = 13) were cultured with or without EP. Cytokine expression in T-cell phenotypes was analyzed by multicolor flow cytometry, whereas desmosine concentration, a specific marker of elastin degradation, was measured in sera.

Results

Compared with control, the percentage of IL-4 (Th2) producing CD4⁺ T-cells was decreased in COPD patients (35.3 ± 3.4% and 26.3 ± 2.4%, respectively, p < 0.05), whereas no significant differences were found with IFN-γ (Th1) and IL-17A (Th17). Among COPD patients, two subpopulations were observed based on the percentage of IL-4 (Th2) producing CD4⁺ T-cells, of which only one expressed high IL-4 levels in association with high levels of desmosine and strong smoking exposure (n = 7). Upon stimulation with VGVAPG, a bioactive EP motif, the percentage of CD4⁺ T cells expressing IL-4 significantly increased in COPD patients (p < 0.05), but not in controls. The VGVAPG-induced increase in IL-4 was inhibited in the presence of analogous peptide antagonizing VGVAPG/elastin receptor (S-gal) interactions.

Conclusions

The present study demonstrates that the VGVAPG elastin peptide modulates CD4⁺ T-cells IL-4 production in COPD. Monitoring IL-4 in circulating CD4⁺ T-cells may help to better characterize COPD phenotypes and could open a new pharmacologic opportunity through CD4⁺ T-cells stimulation via the VGVAPG/S-gal receptor in order to favor an anti-inflammatory response in those COPD patients.

The role of Th17 cells in viral infections

The present review provides an overview of recent advances regarding the function of Th17 cells and their produced cytokines in the progression of viral diseases. Viral infections alone do not lead to virus-induced malignancies, as both genetic and host safety factors are also involved in the occurrence of malignancies. Acquired immune responses, through the differentiation of Th17 cells, form the novel components of the Th17 cell pathway when reacting with viral infections all the way from the beginning to its final stages. As a result, instead of inducing the right immune responses, these events lead to the suppression of the immune system. In fact, the responses from Th17 cells during persistent viral infections causes chronic inflammation through the production of IL-17 and other cytokines which provide a favorable environment for tumor growth and its development. Additionally, during the past decade, these cells have been understood to be involved in tumor progression and metastasis. However, further research is required to understand Th17 cells' immune mechanisms in the vast variety of viral diseases. This review aims to determine the roles and effects of the immune system, especially Th17 cells, in the progression of viral diseases; which can be highly beneficial for the diagnosis and treatment of these infections.

Smoking Associated T-Cell Imbalance in Patients With Chronic Pain

INTRODUCTION

Smoking is associated with several diseases and affects the immune system. Recently, published data demonstrate an involvement of T helper 17 cells (Th17) and regulatory T cells (Tregs) in the pathogenesis of chronic pain and pain intensity. The role of these T-cell subsets in smoking patients with chronic pain is nebulous so far. We therefore analyzed Th17 cells and Tregs in smokers and nonsmokers with chronic pain.

METHODS

Analyses of T-cell subsets, mRNA expression and T-cell related cytokine profiles were done in 44 patients with chronic pain. Twenty-two of these patients were smokers. Numbers of T-cell subsets were quantified by flow cytometry. mRNA expression of the Th17- (RAR-related orphan receptor gamma) and Treg (forkhead box protein P3)-specific transcription factors was determined by quantitative real-time PCR, and levels of cytokines were measured by Human Cytokine Multiplex Immunoassay.

RESULTS

Compared to nonsmokers, smokers showed significantly enhanced pain levels. On cellular basis, the number of pro-inflammatory Th17 cells (smokers: 2.2 ± 2.5% vs. nonsmokers: 0.5 ± 0.4%; p = .04) was increased, whereas the number of anti-inflammatory Tregs (smokers: 2.5 ± 0.9% vs. nonsmokers: 3.1 ± 1.1%; p = .02) was significantly decreased, resulting in an altered Th17/Treg ratio (Th17/Treg ratio: 0.9 ± 1.0 in smokers vs. 0.2 ± 0.1 in nonsmokers; p < .01). These findings were confirmed by quantitative real-time PCR. Analyses of cytokines revealed only marginal changes.

CONCLUSIONS

In patients with chronic pain, smoking is associated with enhanced pain levels together with an imbalance of the Th17/Treg ratio. The shift of the Th17/Treg ratio toward inflammation may explain in part the increased pain intensity in these patients.

IMPLICATIONS

Smoking is associated with increased pain levels and a pro-inflammatory Th17/Treg shift. The altered Th17/Treg ratio in smoking patients with chronic pain may partly explain their increased pain intensity.

GERMAN CLINICAL TRIAL REGISTER (DRKS)

Registration Trial DRKS00005954.

Relationship of Serum Levels of IL-17, IL-18, TNF-α, and Lung Function Parameters in Patients with COPD, Asthma-COPD Overlap, and Bronchial Asthma

Determination of markers of systemic inflammation is one of the important directions in the study of pathogenesis and improvement of diagnosis of chronic obstructive pulmonary disease (COPD), asthma-COPD overlap (ACO), and bronchial asthma (BA). The aim of our work was a comparative study of the features of changes in serum levels of IL-17, IL-18, and TNF-α in patients with COPD, ACO, and BA with various severity of the disease, as well as evaluation of the relationship between the level of these cytokines and lung ventilation function. A total of 147 patients with COPD (n = 58), ACO (n = 57), and BA (n = 32) during a stable period have been examined in this study. The control group included 21 healthy nonsmokers with similar sex-age indicators. Serum levels of IL-17, IL-18, and TNF-α were determined by ELISA. The concentrations of these cytokines in the circulation in the studied patients with COPD, ACO, and BA were higher than those in healthy nonsmokers (p ≤ 0.001). IL-17 and IL-18 levels in the blood serum were comparable in all examined patients. The mean TNF-α concentrations in the circulation in COPD and ACO were significantly higher than those in BA (p < 0.001). In patients with COPD, the levels of IL-17 and TNF-α increased progressively against the background of a decrease in numerous spirometric indicators, which allows us to consider these cytokines as systemic biomarkers of disease severity. In BA, the inverse correlations between the level of IL-17 and FEV1/FVC (%) and FEV1 have been found. In patients with ACO, the increase in IL-18 levels was associated with a decrease in FEV1 and TNF-α with FEV1/FVC (%). These findings indicate that IL-17, IL-18, and TNF-α can participate in the mechanisms of systemic inflammation and the genesis of disorders of airway obstruction in COPD, AСO, and BA. An increase in the levels of IL-17 and TNF-α may be associated with impaired bronchial patency in COPD and BA. The established associations of the IL-18 concentration in the blood serum and FEV1 only in patients with ACO allow using the level of IL-18 as a potential marker of the degree of impaired airway obstruction in this disease.

Cigarette smoking induces human CCR6+Th17 lymphocytes senescence and VEGF-A secretion

Chronic exposure to environmental pollutants is often associated with systemic inflammation. As such, cigarette smoking contributes to inflammation and lung diseases by inducing senescence of pulmonary cells such as pneumocytes, fibroblasts, and endothelial cells. Yet, how smoking worsens evolution of chronic inflammatory disorders associated with Th17 lymphocytes, such as rheumatoid arthritis, psoriasis, Crohn’s disease, and multiple sclerosis, is largely unknown. Results from human studies show an increase in inflammatory CD4⁺ Th17 lymphocytes at blood- and pulmonary level in smokers. The aim of the study was to evaluate the sensitivity of CD4⁺ Th17 lymphocytes to cigarette smoke-induced senescence. Mucosa-homing CCR6⁺ Th17- were compared to CCR6^neg -and regulatory T peripheral lymphocytes after exposure to cigarette smoke extract (CSE). Senescence sensitivity of CSE-exposed cells was assessed by determination of various senescence biomarkers (β-galactosidase activity, p16^Ink4a- and p21 expression) and cytokines production. CCR6⁺ Th17 cells showed a higher sensitivity to CSE-induced senescence compared to controls, which is associated to oxidative stress and higher VEGFα secretion. Pharmacological targeting of ROS- and ERK1/2 signalling pathways prevented CSE-induced senescence of CCR6⁺Th17 lymphocytes as well as VEGFα secretion. Altogether, these results identify mechanisms by which pro-oxidant environmental pollutants contribute to pro-angiogenic and pathogenic CCR6⁺Th17 cells, therefore potential targets for therapeutic purposes.

Systemic Th17 response in the presence of periodontal inflammation

The relationship between periodontitis and the pathogenesis of other inflammatory diseases, such as diabetes, rheumatoid arthritis and obesity has been an important topic of study in recent decades. The Th17 pathway plays a significant role in how local inflammation can influence systemic inflammation in the absence of systemic pathology.

Elevated Th17 cell frequencies and Th17/Treg ratio are associated with airway hyperresponsiveness in asthmatic children

Introduction: The elevation of T helper (Th)17 cell frequencies and the imbalance of Th17/regulatory T (Treg) cells occur in asthma pathogenesis. Airway hyperresponsiveness (AHR) is a cardinal feature of asthma, and Th17 responses can promote AHR. We hypothesized that changes in Th17 cells and the Th17/Treg ratio correlate with AHR in asthmatic children.Methods: Twenty asthmatic children and twenty healthy children were included in the study. The peak expiratory flow (PEF) % pred, forced expiratory volume in 1 s (FEV₁) % pred and the FEV₁/forced vital capacity (FVC) ratio were measured in all subjects. Methacholine challenge test (MCT) was performed in asthmatic children. Flow cytometric analysis was used to determine the proportions of Th17 and Treg cells in peripheral blood mononuclear cells. ELISA was used to assess serum levels of interleukin (IL)-17A and IL-10.Results: Th17 cell frequencies (2.272 ± 0.207% in asthmatics, 1.193 ± 0.131% in controls, P < 0.01) and Th17/Treg ratios (0.371 ± 0.0387 in asthmatics, 0.183 ± 0.020 in controls, P < 0.01) were significantly increased in asthmatic children compared to controls. In asthmatic children, the MCT grade had positive correlations with the Th17 cell frequencies [r = 0.718, P < 0.01], serum IL-17A level [r = 0.753, P < 0.01] and Th17/Treg ratio [r = 0.721, P < 0.01], while the log₁₀PD20-FEV₁ value was negatively correlated with the Th17 cell frequencies [r = -0.654, P < 0.01], serum IL-17A level [r = -0.652, P < 0.01] and Th17/Treg ratio [r = -0.625, P < 0.01].Conclusion: Th17 cell, IL-17A and Th17/Treg ratio were positively correlated with AHR in asthmatic children. It may be helpful to monitor Th17 cells and the Th17/Treg ratio as indicators of AHR in clinical practice.

Genetic variants in IL17A and serum levels of IL-17A are associated with COPD related to tobacco smoking and biomass burning

IL-17A is an important pro-inflammatory cytokine involved in the inflammatory response in chronic obstructive pulmonary disease (COPD). To evaluate the role played by single nucleotide polymorphisms of IL17A and protein levels in susceptibility to COPD, 1,807 subjects were included in a case-control study; 436 had COPD related to tobacco smoking (COPD-S) and 190 had COPD related to biomass burning (COPD-BB). Six hundred fifty-seven smokers without COPD (SWOC) and 183 biomass burning-exposed subjects (BBES) served as the respective control groups. The CC genotype and C allele of rs8193036 were associated with COPD (COPD-S vs. SWOC: p < 0.05; OR = 3.01, and OR = 1.28, respectively), as well as a recessive model (p < 0.01; OR = 2.91). Significant differences in serum levels were identified between COPD-S vs. SWOC, COPD-S vs. COPD-BB, and SWOC vs. BBES (p < 0.01). By comparing genotypes in the COPD-BB group TT vs. CC and TC vs. CC (p < 0.05), we found lower levels for the CC genotype. Logistic regression analysis by co-variables was performed, keeping the associations between COPD-S vs. SWOC with both polymorphisms evaluated (p < 0.05), as well as in COPD-BB vs. BBES but with a reduced risk of exacerbation (p < 0.05). In conclusion, polymorphisms in IL17A are associated with COPD. Serum levels of IL-17A were higher in smokers with and without COPD.

sFRP2 promotes airway inflammation and Th17/Treg imbalance in COPD via Wnt/β-catenin pathway

Imbalance between inflammatory Th17 cells and immunosuppressive regulatory T cells (Treg) contributes to the progression of chronic obstructive pulmonary disease (COPD). We aims to investigate roles and mechanisms of secreted frizzled-related protein 2 (sFRP2) in airway inflammation and Th17/Treg differentiation in COPD. sFRP2 was significantly upregulated in the serum of patients with COPD and in human bronchial epithelial (HBE) cells that were exposed to cigarette smoke extract (CSE). sFRP2 was negatively correlated with FEV1/FVC. CSE increased IL-6 and TNF-α in HBE cells, which was reversed by sFRP2 silencing. CSE exposure elevated the percentage of Th17 in CD3+ CD8- cells while reduced the percentage of Treg in CD4+CD25+ cells. Knockdown of sFRP2 in peripheral blood mononuclear cells (PBMCs) attenuated Th17 differentiation and induced Treg differentiation. CSE suppressed the expression of β-catenin and Cyclin D1 in PBMCs while knockdown of sFRP2 markedly reversed the inhibitory effects of CSE. Wnt/β-catenin inhibition by Dickkopf-1 reversed the inhibitory effect of si-sFRP2 on the production of inflammatory cytokines and imbalance between Th17 and Treg cells caused by CSE. CSE induced sFRP2 potentiated airway inflammation and disturbed Th17/Treg homeostasis by inhibiting β-catenin.

Regulatory T Cells in Respiratory Health and Diseases

Respiratory diseases compromise the health of millions of people all over the world and are strongly linked to the immune dysfunction. CD4+FOXP3+ T regulatory cells, also known as Tregs, have a central role maintaining tissue homeostasis during immune responses. Their activity and clinical impact have been widely studied in different clinical conditions including autoimmune diseases, inflammatory conditions, and cancer, amongst others. Tregs express transcription factor forkhead box P3 (FOXP3), which allows regulation of the immune response through anti-inflammatory cytokines such as IL-10 or transforming growth factor beta (TGF-β) and direct cell-to-cell interaction. Maintenance of immune tolerance is achieved via modulation of effector CD4+ T helper 1, 2 or 17 (Th1, Th2, Th17) cells by Tregs. This review highlights the recent progress in the understanding of Tregs in different disorders of the respiratory system.

Dysregulation of the Tryptophan Pathway Evidences Gender Differences in COPD

Increased activity of indoleamine 2,3-dioxygenase (IDO) and tryptophan hydroxylase (TPH) have been reported in individuals with chronic obstructive pulmonary disease (COPD). We therefore investigated the effect of gender stratification upon the observed levels of tryptophan metabolites in COPD. Tryptophan, serotonin, kynurenine, and kynurenic acid were quantified in serum of never-smokers (n = 39), smokers (n = 40), COPD smokers (n = 27), and COPD ex-smokers (n = 11) by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The individual metabolite associations with lung function, blood, and bronchoalveolar lavage (BAL) immune-cell composition, as well as chemokine and cytokine levels, were investigated. Stratification by gender and smoking status revealed that the observed alterations in kynurenine and kynurenic acid, and to a lesser extent serotonin, were prominent in males, irrespective of COPD status (kynurenine p = 0.005, kynurenic acid p = 0.009, and serotonin p = 0.02). Inferred serum IDO activity and kynurenine levels decreased in smokers relative to never-smokers (p = 0.005 and p = 0.004, respectively). In contrast, inferred tryptophan hydroxylase (TPH) activity and serotonin levels showed an increase with smoking that reached significance with COPD (p = 0.01 and p = 0.01, respectively). Serum IDO activity correlated with blood CXC chemokine ligand 9 (CXCL9, p = 0.0009, r = 0.93) and chemokine (C-C motif) ligand 4 (CCL4.(p = 0.04, r = 0.73) in female COPD smokers. Conversely, serum serotonin levels correlated with BAL CD4+ T-cells (%) (p = 0.001, r = 0.92) and CD8+ T-cells (%) (p = 0.002, r = -0.90) in female COPD smokers, but not in male COPD smokers (p = 0.1, r = 0.46 and p = 0.1, r = -0.50, respectively). IDO- and TPH-mediated tryptophan metabolites showed gender-based associations in COPD, which were primarily driven by smoking status.

T Cells as an Emerging Target for Chronic Pain Therapy

The immune system is critically involved in the development and maintenance of chronic pain. However, T cells, one of the main regulators of the immune response, have only recently become a focus of investigations on chronic pain pathophysiology. Emerging clinical data suggest that patients with chronic pain have a different phenotypic profile of circulating T cells compared to controls. At the preclinical level, findings on the function of T cells are mixed and differ between nerve injury, chemotherapy, and inflammatory models of persistent pain. Depending on the type of injury, the subset of T cells and the sex of the animal, T cells may contribute to the onset and/or the resolution of pain, underlining T cells as a major player in the transition from acute to chronic pain. Specific T cell subsets release mediators such as cytokines and endogenous opioid peptides that can promote, suppress, or even resolve pain. Inhibiting the pain-promoting functions of T cells and/or enhancing the beneficial effects of pro-resolution T cells may offer new disease-modifying strategies for the treatment of chronic pain, a critical need in view of the current opioid crisis.

Increased IFN-γ-producing Th17/Th1 cells and their association with lung function and current smoking status in patients with chronic obstructive pulmonary disease

Background

Th17 cells are believed to be important proinflammatory cells in the pathogenesis of chronic obstructive pulmonary disease (COPD). Recent evidence demonstrates that Th17 cells display substantial developmental plasticity, giving rise to Th17/Th1 cells that secret both IL-17 and IFN-γ and are more pathogenic in inflammatory diseases. The aim of this study was to examine the distribution of circulating Th17/Th1 subpopulation and its association with disease severity in patients with COPD.

Methods

Blood samples were obtained from 21 never-smokers, 31 smokers with normal lung function and 83 patients with COPD. The frequencies of Th17 cells and the Th17/Th1 subset were measured using flow cytometry. Plasma concentrations of IL-6, transforming growth factor (TGF)-β1 and IL-12 were determined by ELISA. The associations of Th17/Th1 cells with lung function and smoking were evaluated.

Results

In peripheral blood, significantly increased proportions of Th17/Th1 cells among CD4 cells and Th17 cells were found in COPD patients compared with never-smokers and smokers with normal lung function. The percentages of Th17/Th1 cells showed correlations with forced expiratory volume in 1 (FEV₁) % predicted value (r = − 0.244, p < 0.05), and higher proportions of Th17/Th1 cells in GOLD stage IV patients compared with stage I patients. The percentages of Th17/Th1 cells were significantly higher in current smokers compared with ex-smoker COPD patients, and positively correlated with pack-years of smoking (r = 0.352, p < 0.01). The plasma concentrations of IL-6, TGF-β1 and IL-12 were significantly increased in patients with COPD compared with never-smokers and smokers with normal lung function.

Conclusion

Our results revealed correlations of proportions of IFN-γ-producing Th17/Th1 cells with lung function and smoking, suggesting that increased Th17/Th1 cells may play a role in COPD progression.

LncRNAs NR-026690 and ENST00000447867 are upregulated in CD4+ T cells in patients with acute exacerbation of COPD

Objective

The aim of the study was to determine the expression profile of long noncoding RNAs (lncRNAs) in CD4+ T cells from COPD patients and explore the clinical value of the lncRNAs.

Methods

First, microarray analysis was performed. Differentially expressed lncRNAs were validated by quantitative real-time reverse transcription-PCR (qRT-PCR) in samples from 56 patients with acute exacerbations of COPD (AECOPD), 56 patients with stable COPD, and 35 healthy controls. Meanwhile, the clinical value was tested by receiver operating characteristic curve analysis. The functions of lncRNAs were analyzed by the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database. The potential target genes that might be regulated by NR-026690 and ENST00000447867 were identified by the lncRNA-mRNA network and competing endogenous RNA network. The transcriptional expression level of rap guanine nucleotide exchange factor 3 (RAPGEF3) was tested by qRT-PCR. The correlation of the expression between NR-026690, ENST00000447867, and RAPGEF3 was analyzed by Spearman's correlation test.

Results

We found that the relative expression levels of ENST00000447867 and NR-026690 in the CD4+ T cells of AECOPD patients were significantly higher than in the stable COPD patients and control subjects by microarray and qRT-PCR validation. The transcriptional expression level of RAPGEF3 in the CD4+ T cells was significantly higher in the AECOPD group compared to the control group (P<0.01) and the stable COPD group (P<0.05). RAPGEF3 expression was positively associated with NR-026690 (r=0.4925, P<0.01) and ENST00000447867 (r=0.4065, P<0.01).

Conclusion

NR-026690 and ENST00000447867 might be potential biomarkers for COPD. They might affect RAPGEF3 as miRNA sponges to regulate COPD development.

Generation and Immune Regulation of CD4+CD25-Foxp3+ T Cells in Chronic Obstructive Pulmonary Disease

The imbalance of CD4⁺Foxp3⁺ T cell subsets is reportedly involved in abnormal inflammatory immune responses in patients with chronic obstructive pulmonary disease (COPD). However, the possible role of CD4⁺CD25^-Foxp3⁺ T cells in immune regulation in COPD remains to be investigated. In the current study, distribution and phenotypic characteristics of CD4⁺CD25^-Foxp3⁺ T cells from peripheral blood were determined by flow cytometry; the origin, immune function and ultimate fate of CD4⁺CD25^-Foxp3⁺ T cells were further explored in vitro. It was observed that circulating CD4⁺CD25^-Foxp3⁺ T cells were significantly increased in stable COPD patients (SCOPD) and resembled central memory or effector memory T cells. Compared with peripheral CD4⁺CD25⁺Foxp3⁺ T cells, peripheral CD4⁺CD25^-Foxp3⁺ T cells showed a lower expression of Foxp3, CTLA-4, HELIOS, and TIGIT, but a higher expression of CD127 and KI-67, suggesting that CD4⁺CD25^-Foxp3⁺ T cells lost the expression of Tregs-associated molecules following the reduction in CD25. Unexpectedly, our study found that transforming growth factor-β1 (TGFβ1) decreased CD25 expression and played a critical role in the generation of CD4⁺CD25^-Foxp3⁺ T cells from CD4⁺CD25⁺Foxp3⁺ T cells. Phenotypic analysis further revealed that both inducible and peripheral CD4⁺CD25^-Foxp3⁺ T cells exhibited the features of activated conventional T cells. Importantly, memory CD4⁺CD25^-Foxp3⁺ T cells facilitated the proliferation and differentiation of naïve CD4⁺ T cells into Th17 cells in the presence of IL-1β, IL-6, IL-23, and TGFβ1. Finally, a fraction of CD4⁺CD25^-Foxp3⁺ T cells, exhibiting instability and plasticity, were converted to Th17 cells when subjected to Th17 cell-polarizing condition. Taken together, we propose that TGFβ1 is responsible for the generation of CD4⁺CD25^-Foxp3⁺ T cells, and these cells functionally exert an auxiliary effect on Th17 cells generation and might perpetuate chronic inflammation in COPD.

Efficacy and safety of Xuebijing injection and its influence on immunomodulation in acute exacerbations of chronic obstructive pulmonary disease: study protocol for a randomized controlled trial

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the leading cause of mortality in chronic obstructive pulmonary disease (COPD). Traditional Chinese medicine (TCM) has been widely used in Asia as an adjunct treatment for AECOPD to improve the patients' symptoms. Xuebijing (XBJ) injection is one of the major herbal medicines used in TCM. Previous small-sample clinical trials have proven its efficacy and safety in the treatment of AECOPD; however, the current data on XBJ as an adjunct therapy are insufficient. The present study will be a multi-center randomized clinical trial (RCT) to evaluate the efficacy and safety of XBJ injection in AECOPD and explore its influence on the immune function based on the altered levels of T cells.

METHODS

This study will be a prospective, randomized, placebo-controlled, blinded, multi-center trial. A total of 300 eligible patients will be randomly assigned to the treatment or placebo control group in a 1:1 ratio using a central randomization system. The treatment group will receive routine medication plus XBJ injection, and the control group will receive routine medication plus 0.9% NaCl injection. The patients will receive the corresponding treatment for 5 days starting within 24 h of enrollment. The primary outcome, the of rate endotracheal intubation, will be evaluated on day 28 after treatment. The secondary outcomes will include changes in immune and inflammatory indicators, respiratory support, mortality rate after 28 days, blood gas analysis, improvement in Acute physiology and chronic health evaluation (APACHE) II scores and clinical symptoms, and the length and cost of intensive care unit stay and hospitalization. The safety of the interventions will be assessed throughout the trial.

DISCUSSION

This is the first and largest randomized, controlled, blinded trial that evaluates the efficacy of XBJ injection as adjuvant therapy for AECOPD. The results of this trial will provide valuable clinical evidence for recommendations on the management of the disease and identify the underlying mechanisms.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02937974 . Registered on 13 October 2016. Chinese clinical trial registry, ChiCTR-IPR-17011667. Registered on 15 June 2017.

Chronic Obstructive Pulmonary Disease in Latin America

The PLATINO and PREPOCOL population-based studies documented the prevalence of chronic obstructive pulmonary disease (COPD) in several Latin American (Mexico City, Sao Paulo, Montevideo, Santiago and Caracas) and Colombian (Medellin, Bogota, Barranquilla, Bucaramanga and Cali) cities. COPD ranged between 6.2 and 19.6% in individuals ≥40 years of age, with substantial rates of underdiagnosis (up to 89%) but also overdiagnosis, mostly due to the lack of spirometric confirmation. The main risk factor was tobacco smoking, but male gender and age were also associated with COPD. COPD in never smokers represented about one third of the cases and was associated with previous history of tuberculosis or a diagnosis of asthma. COPD associated with biomass smoke exposure was a common clinical phenotype in Latin America, found as a risk factor in PREPOCOL and other observational studies in the region. Smoking has been decreasing in Latin America and efforts have been made to implement cleaner biomass stoves. Unfortunately, treatment of COPD in Latin America remains highly variable with low rates of smoking cessation counselling, low use of inhaled bronchodilators and influenza vaccination. A primary-care approach to COPD, particularly in the form of integrated programs is lacking but would be critical to improving rates of diagnosis and treatment of COPD.

An airway epithelial IL-17A response signature identifies a steroid-unresponsive COPD patient subgroup

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a heterogeneous smoking-related disease characterized by airway obstruction and inflammation. This inflammation may persist even after smoking cessation and responds variably to corticosteroids. Personalizing treatment to biologically similar "molecular phenotypes" may improve therapeutic efficacy in COPD. IL-17A is involved in neutrophilic inflammation and corticosteroid resistance, and thus may be particularly important in a COPD molecular phenotype.

METHODS

We generated a gene expression signature of IL-17A response in bronchial airway epithelial brushings from smokers with and without COPD (n = 238), and validated it using data from 2 randomized trials of IL-17 blockade in psoriasis. This IL-17 signature was related to clinical and pathologic characteristics in 2 additional human studies of COPD: (a) SPIROMICS (n = 47), which included former and current smokers with COPD, and (b) GLUCOLD (n = 79), in which COPD participants were randomized to placebo or corticosteroids.

RESULTS

The IL-17 signature was associated with an inflammatory profile characteristic of an IL-17 response, including increased airway neutrophils and macrophages. In SPIROMICS the signature was associated with increased airway obstruction and functional small airways disease on quantitative chest CT. In GLUCOLD the signature was associated with decreased response to corticosteroids, irrespective of airway eosinophilic or type 2 inflammation.

CONCLUSION

These data suggest that a gene signature of IL-17 airway epithelial response distinguishes a biologically, radiographically, and clinically distinct COPD subgroup that may benefit from personalized therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01969344.

FUNDING

Primary support from the NIH, grants K23HL123778, K12HL11999, U19AI077439, DK072517, U01HL137880, K24HL137013 and R01HL121774 and contracts HHSN268200900013C, HHSN268200900014C, HHSN268200900015C, HHSN268200900016C, HHSN268200900017C, HHSN268200900018C, HHSN268200900019C and HHSN268200900020C.

Recovery from acute lung injury can be regulated via modulation of regulatory T cells and Th17 cells

Acute lung injury (ALI) is a severe inflammatory disease, for which no specific treatment exists. The decreased ratio of regulatory T cells (CD4⁺ CD25⁺ FoxP3 Tregs) and Th17 cells is implicated in ALI and inflammation. We here investigated whether maintaining the balance of CD4⁺ CD25⁺ Foxp3⁺ Tregs and Th17 cells can alleviate lung injury. For CD4⁺ CD25⁺ FoxP3 Treg depletion, 200 μg of an anti-CD25 antibody was administered intraperitoneally per mouse on days -3 and -1 before lipopolysaccharide (LPS) instillation. And 150 μg of TGF-β was administered intraperitoneally per mouse on day 0 after LPS instillation. To down-regulate of Th17 cells, 200 μg per mouse of isotype, IL-17 or IL-22 antibodies were injected intraperitoneally into mice at days 0 after LPS instillation. We detected lung morphology; lung wet-to-dry weight ratio; protein concentration, the count of total cells, neutrophils and macrophages, and cytokines in bronchoalveolar lavage fluid (BALF). And we also evaluated the percentage of CD4⁺ CD25⁺ Foxp3⁺ Tregs in lung, and Th17 cells in lung. CD4⁺ CD25⁺ Foxp3⁺ Tregs depletion via anti-CD25 treatment or TGF-β neutralization delayed recovery of ALI. The prolonged inflammation was mainly dominated by neutrophils, macrophages and Th17 cells. Furthermore, inhibition of Th17 cells via monoclonal antibodies against IL-17 and IL-22 alleviated ALI inflammation by inhibiting the recruitment of neutrophils and macrophages, increasing the number of CD4⁺ CD25⁺ Foxp3⁺ Tregs. Our findings support a critical role for CD4⁺ CD25⁺ Foxp3⁺ Tregs in regulating from ALI pathophysiology, and a potential therapeutic role for the inhibition of Th17 cells in ALI treatment. These findings provide a rationale for treating patients with ALI by modulating CD4⁺ CD25⁺ Foxp3⁺ Tregs and Th17 cells.