Differences in systemic adaptive immunity contribute to the 'frequent exacerbator' COPD phenotype

Causal Role of Immune Cells in Chronic Obstructive Pulmonary Disease: A Two-Sample Mendelian Randomization Study

Accumulating evidence has highlighted the importance of immune cells in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the understanding of the causal association between immunity and COPD remains incomplete due to the existence of confounding variables. In this study, we employed a two-sample Mendelian randomization (MR) analysis, utilizing the genome-wide association study database, to investigate the causal association between 731 immune-cell signatures and the susceptibility to COPD from a host genetics perspective. To validate the consistency of our findings, we utilized MR analysis results of lung function data to assess directional concordance. Furthermore, we employed MR-Egger intercept tests, Cochrane's Q test, MR-PRESSO global test, and "leave-one-out" sensitivity analyses to evaluate the presence of horizontal pleiotropy, heterogeneity, and stability, respectively. Inverse variance weighting results showed that seven immune phenotypes were associated with the risk of COPD. Analyses of heterogeneity and pleiotropy analysis confirmed the reliability of MR results. These results highlight the interactions between the immune system and the lungs. Further investigations into their mechanisms are necessary and will contribute to inform targeted prevention strategies for COPD.

The predictive value of baseline symptom score and the peripheral CD4CD8 double-positive T cells in patients with AECOPD

BACKGROUND

Accurate prediction of acute exacerbation helps select patients with chronic obstructive pulmonary disease (COPD) for individualized therapy. The potential of lymphocyte subsets to function as clinical predictive factors for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) remains uncertain.

METHODS

In this single-center prospective cohort study with a 2-year follow-up, 137 patients aged 51 to 79 with AECOPD were enrolled. We examined the prognostic indicators of AECOPD by analyzing lymphocyte subsets and baseline symptom score. Furthermore, a predictive model was constructed to anticipate the occurrence of respiratory failure in patients experiencing AECOPD.

RESULTS

The COPD Assessment Test (CAT) score combined with home oxygen therapy and CD4+CD8+ T cells% to predict respiratory failure in AECOPD patients were the best (the area under the curves [AUC] = 0.77, 95% CI: 0.70-0.86, P < 0.0001, sensitivity: 60.4%, specificity: 86.8%). The nomogram model, the C index, calibration plot, decision curve analysis, and clinical impact curve all indicate the model's good predictive performance. The observed decrease in the proportions of CD4+CD8+ T cells appears to be correlated with more unfavorable outcomes.

CONCLUSIONS

The nomogram model, developed to forecast respiratory failure in patients with AECOPD, utilizing variables such as home oxygen therapy, CAT score, and CD4+CD8+ T cells%, demonstrated a high level of practicality in clinical settings. CD4+CD8+ T cells serve as a reliable and readily accessible predictor of AECOPD, exhibiting greater stability compared to other indices. It is less susceptible to subjective influences from patients or physicians. This model facilitated personalized estimations, enabling healthcare professionals to make informed decisions regarding preventive interventions.

Antiviral CD8+ T-cell immune responses are impaired by cigarette smoke and in COPD

BACKGROUND

Virus infections drive COPD exacerbations and progression. Antiviral immunity centres on the activation of virus-specific CD8+ T-cells by viral epitopes presented on major histocompatibility complex (MHC) class I molecules of infected cells. These epitopes are generated by the immunoproteasome, a specialised intracellular protein degradation machine, which is induced by antiviral cytokines in infected cells.

METHODS

We analysed the effects of cigarette smoke on cytokine- and virus-mediated induction of the immunoproteasome in vitro, ex vivo and in vivo using RNA and Western blot analyses. CD8+ T-cell activation was determined in co-culture assays with cigarette smoke-exposed influenza A virus (IAV)-infected cells. Mass-spectrometry-based analysis of MHC class I-bound peptides uncovered the effects of cigarette smoke on inflammatory antigen presentation in lung cells. IAV-specific CD8+ T-cell numbers were determined in patients' peripheral blood using tetramer technology.

RESULTS

Cigarette smoke impaired the induction of the immunoproteasome by cytokine signalling and viral infection in lung cells in vitro, ex vivo and in vivo. In addition, cigarette smoke altered the peptide repertoire of antigens presented on MHC class I molecules under inflammatory conditions. Importantly, MHC class I-mediated activation of IAV-specific CD8+ T-cells was dampened by cigarette smoke. COPD patients exhibited reduced numbers of circulating IAV-specific CD8+ T-cells compared to healthy controls and asthmatics.

CONCLUSION

Our data indicate that cigarette smoke interferes with MHC class I antigen generation and presentation and thereby contributes to impaired activation of CD8+ T-cells upon virus infection. This adds important mechanistic insight on how cigarette smoke mediates increased susceptibility of smokers and COPD patients to viral infections.

Reduced quantity and function of pneumococcal antibodies are associated with exacerbations of COPD in SPIROMICS

While hypogammaglobulinemia is associated with COPD exacerbations, it is unknown whether frequent exacerbators have specific defects in antibody production/function. We hypothesized that reduced quantity/function of serum pneumococcal antibodies correlate with exacerbation risk in the SPIROMICS cohort. We measured total pneumococcal IgG in n = 764 previously vaccinated participants with COPD. In a propensity-matched subset of n = 200 with vaccination within five years (n = 50 without exacerbations in the previous year; n = 75 with one, n = 75 with ≥2), we measured pneumococcal IgG for 23 individual serotypes, and pneumococcal antibody function for 4 serotypes. Higher total pneumococcal IgG, serotype-specific IgG (17/23 serotypes), and antibody function (3/4 serotypes) were independently associated with fewer prior exacerbations. Higher pneumococcal IgG (5/23 serotypes) predicted lower exacerbation risk in the following year. Pneumococcal antibodies are inversely associated with exacerbations, supporting the presence of immune defects in frequent exacerbators. With further study, pneumococcal antibodies may be useful biomarkers for immune dysfunction in COPD.

Contribution of adaptive immunity to human COPD and experimental models of emphysema

The pathophysiology of chronic obstructive pulmonary disease (COPD) and the undisputed role of innate immune cells in this condition have dominated the field in the basic research arena for many years. Recently, however, compelling data suggesting that adaptive immune cells may also contribute to the progressive nature of lung destruction associated with COPD in smokers have gained considerable attention. The histopathological changes in the lungs of smokers can be limited to the large or small airways, but alveolar loss leading to emphysema, which occurs in some individuals, remains its most significant and irreversible outcome. Critically, however, the question of why emphysema progresses in a subset of former smokers remained a mystery for many years. The recognition of activated and organized tertiary T- and B-lymphoid aggregates in emphysematous lungs provided the first clue that adaptive immune cells may play a crucial role in COPD pathophysiology. Based on these findings from human translational studies, experimental animal models of emphysema were used to determine the mechanisms through which smoke exposure initiates and orchestrates adaptive autoreactive inflammation in the lungs. These models have revealed that T helper (Th)1 and Th17 subsets promote a positive feedback loop that activates innate immune cells, confirming their role in emphysema pathogenesis. Results from genetic studies and immune-based discoveries have further provided strong evidence for autoimmunity induction in smokers with emphysema. These new findings offer a novel opportunity to explore the mechanisms underlying the inflammatory landscape in the COPD lung and offer insights for development of precision-based treatment to halt lung destruction.

Screening and identification of tissue-infiltrating immune cells and genes for patients with emphysema phenotype of COPD

Objective

To study the tissue-infiltrating immune cells of the emphysema phenotype of chronic obstructive pulmonary disease (COPD) and find the molecular mechanism related to the development of emphysema to offer potential targets for more precise treatment of patients with COPD.

Methods

Combined analyses of COPD emphysema phenotype lung tissue-related datasets, GSE47460 and GSE1122, were performed. CIBERSORT was used to assess the distribution of tissue-infiltrating immune cells. Weighted gene co-expression network analysis (WGCNA) was used to select immune key genes closely related to clinical features. Rt-qPCR experiments were used for the validation of key genes. Emphysema risk prediction models were constructed by logistic regression analysis and a nomogram was developed.

Results

In this study, three immune cells significantly associated with clinical features of emphysema (FEV1 post-bronchodilator % predicted, GOLD Stage, and DLCO) were found. The proportion of neutrophils (p=0.025) infiltrating in the emphysema phenotype was significantly increased compared with the non-emphysema phenotype, while the proportions of M2 macrophages (p=0.004) and resting mast cells (p=0.01) were significantly decreased. Five immune-related differentially expressed genes (DEGs) were found. WGCNA and clinical lung tissue validation of patients with emphysema phenotype were performed to further screen immune-related genes closely related to clinical features. A key gene (SERPINA3) was selected and included in the emphysema risk prediction model. Compared with the traditional clinical prediction model (AUC=0.923), the combined prediction model, including SERPINA3 and resting mast cells (AUC=0.941), had better discrimination power and higher net benefit.

Conclusion

This study comprehensively analyzed the tissue-infiltrating immune cells significantly associated with emphysema phenotype, including M2 macrophages, neutrophils, and resting mast cells, and identified SERPINA3 as a key immune-related gene.

Usefulness of Glucose to Lymphocyte Ratio to Predict in-Hospital Mortality in Patients with AECOPD Admitted to the Intensive Care Unit

The purpose of this study was to investigate the relationship between glucose to lymphocyte ratio (GLR) and the outcome of acute exacerbation chronic obstructive pulmonary disease (AECOPD) patients admitted to the intensive care unit (ICU). This study included 3573 patients from the eICU Collaborative Research Database (eICU-CRD) and 926 AECOPD patients admitted to ICU from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. The optimal cutoff value for GLR was 5.6. Kaplan-Meier analysis demonstrated that patients in lower GLR (< 5.6) group showed a better overall survival than patients in higher GLR (≥ 5.6) group in all sets. Multivariate Cox regression analysis demonstrated that age, Sequential Organ Failure Assessment (SOFA) score, SpO2, albumin and GLR are independent predictors of poor overall survival in the training cohort and were incorporated into the nomogram for in-hospital mortality as independent factors. The nomogram exhibited excellent discrimination with C-indexes in training cohort, internal validation and external validation cohort were (0.801, 95%CI: 0.769-0.863), (0.805, 95%CI: 0.759-0.851) and (0.811, 95%CI: 0.772-0.850), respectively. The calibration plot indicated an adequate fit of the nomogram for predicting the risk of in-hospital mortality in all sets. Moreover, the ROC analyses demonstrated that the discrimination abilities of GLR were better than other blood-based inflammatory biomarkers. As an easily available biomarker, GLR can independently predict the in-hospital mortality in AECOPD patients admitted to ICU. The nomogram combining GLR with other significant indicators exhibited excellence predictive performance for in-hospital mortality.

Low Eosinophil Phenotype Predicts Noninvasive Mechanical Ventilation Use in Patients with Hospitalized Exacerbations of COPD

Rationale

Objective

Methods

Results

Conclusion

Bacterial and viral infections and related inflammatory responses in chronic obstructive pulmonary disease

In chronic obstructive pulmonary disease (COPD) patients, bacterial and viral infections play a relevant role in worsening lung function and, therefore, favour disease progression. The inflammatory response to lung infections may become a specific indication of the bacterial and viral infections. We here review data on the bacterial-viral infections and related airways and lung parenchyma inflammation in stable and exacerbated COPD, focussing our attention on the prevalent molecular pathways in these different clinical conditions. The roles of macrophages, autophagy and NETosis are also briefly discussed in the context of lung infections in COPD. Controlling their combined response may restore a balanced lung homeostasis, reducing the risk of lung function decline. KEY MESSAGE Bacteria and viruses can influence the responses of the innate and adaptive immune system in the lung of chronic obstructive pulmonary disease (COPD) patients. The relationship between viruses and bacterial colonization, and the consequences of the imbalance of these components can modulate the inflammatory state of the COPD lung. The complex actions involving immune trigger cells, which activate innate and cell-mediated inflammatory responses, could be responsible for the clinical consequences of irreversible airflow limitation, lung remodelling and emphysema in COPD patients.

Identification of Metabolism-Associated Molecular Subtypes of Chronic Obstructive Pulmonary Disease

Purpose

This study aimed to identify the COPD molecular subtypes reflecting pulmonary function damage on the basis of metabolism-related gene expression, which provided the opportunity to study the metabolic heterogeneity and the association of metabolic pathways with pulmonary function damage.

Methods

Univariate linear regression and the Boruta algorithm were used to select metabolism-related genes associated with forced expiratory volume in the first second (FEV1) and FEV1/forced vital capacity (FVC) in the Evaluation of COPD to Longitudinally Identify Predictive Surrogate Endpoints (ECLIPSE) cohort. COPD subtypes were further identified by consensus clustering with best-fit. Then, we analyzed the differences in the clinical characteristics, metabolic pathways, immune cell characteristics, and transcription features among the subtypes.

Results

This study identified two subtypes (C1 and C2). C1 exhibited higher levels of lower pulmonary function and innate immunity than C2. Ten metabolic pathways were confirmed as key metabolic pathways. The pathways related to N-glycan, hexosamine, purine, alanine, aspartate and glutamate tended to be positively associated with the abundance of adaptive immune cells and negatively associated with the abundance of innate immune cells. In addition, other pathways had opposite trends. All results were verified in Genetic Epidemiology of COPD (COPDGene) datasets.

Conclusion

The two subtypes reflect the pulmonary function damage and help to further understand the metabolic mechanism of pulmonary function in COPD. Further studies are needed to prove the prognostic and therapeutic value of the subtypes.

The Role of Human Leukocyte Antigen-DR in Regulatory T Cells in Patients with Virus-Induced Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background

This study assessed the role of different immune phenotypes of T cells in virus-induced acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Material/Methods

The study involved 103 participants, including individuals with virus-induced AECOPD (n=32), non-virus-induced AECOPD (n=31), and stable COPD (n=20) and individuals who were healthy smokers (n=20). The immune phenotypes of T cells in peripheral blood were evaluated via flow cytometry analysis, and the differences were analyzed.

Results

Patients with virus-induced AECOPD (virus group) had a higher COPD assessment test score on admission than those in the group with non-virus-induced AECOPD (nonvirus group; 25.6±3.8 vs 21.9±4.8, P=0.045). A lower CD4⁺ human leukocyte antigen-DR (HLA-DR)⁺ frequency was found in the peripheral blood of the virus group compared with the nonvirus group (2.2 vs 4.2, P=0.015), and the frequency of CD4⁺ CD25^high CD127^low HLA-DR⁺ in CD4⁺ in the virus group was lower than in the nonvirus group (1.1 vs 3.6, P=0.011). The CD3⁺, CD4⁺, CD8⁺, CD4⁺ central memory T cell, CD4⁺ effector memory T cell (Tem), CD4⁺ end-stage T cell, and CD8⁺ Tem levels in lymphocytes of peripheral blood were lower in exacerbation groups relative to those in the stable COPD and healthy smoking groups, but similar between exacerbation groups. Similar frequencies and levels of T cells between different stagings of COPD were also identified.

Conclusions

The expression of HLA-DR on the cell surface of CD4⁺ regulatory T cells (Tregs) was lower in the peripheral blood of patients with virus-induced AECOPD. The expression of HLA-DR in CD4⁺ Tregs suggested the effect of respiratory viruses on adaptive immunity of patients with AECOPD to some extent.

Neutrophil-to-Lymphocyte Ratio Predicts Clinical Outcome of Severe Acute Exacerbation of COPD in Frequent Exacerbators

Purpose

Frequent exacerbators are a specific phenotype of chronic obstructive pulmonary disease (COPD), whose clinical characteristics and prognostic biomarkers during severe acute exacerbation (AECOPD) have not yet been fully elucidated. The aim of this study was to investigate the clinical features of severe AECOPD in frequent exacerbators and explore the predictive value of the neutrophil-to-lymphocyte ratio (NLR) for outcome in this phenotype during severe exacerbation.

Patients and Methods

A total of 604 patients with severe AECOPD were retrospectively included in the study. Subjects were defined as frequent exacerbators if they experienced two or more exacerbations in the past year. Clinical characteristics and worse outcome (ICU admission, or invasive ventilation, or in-hospital mortality) during severe AECOPD were compared between frequent exacerbators and non-frequent ones. Furthermore, the relationship between NLR and worse outcome in frequent exacerbators was analyzed using logistic regression and receiver operating characteristic (ROC).

Results

Among 604 patients with severe AECOPD, 282 (46.69%) were frequent exacerbators and 322 (53.31%) were non-frequent exacerbators. Compared with the non-frequent ones, frequent exacerbators presented higher levels of NLR (5.93 [IQR, 3.40–9.28] vs 4.41 [IQR, 2.74–6.80]; p<0.001), and more worse outcome incidence (58 [20.57%] vs 38 [11.80%]; p=0.003). Moreover, among the frequent exacerbators, NLR levels in the patients with worse outcome were much higher than in those without worse outcome (11.09 [IQR, 7.74–16.49] vs 5.28 [IQR, 2.93–7.93]; p<0.001). Increased NLR was significantly associated with a higher risk of worse outcome in frequent exacerbators (OR, 1.43; 95% CI, 1.28–1.64; p<0.001). Furthermore, ROC analysis revealed that a cut-off value of 10.23, NLR could predict worse outcome of severe AECOPD in frequent exacerbators (sensitivity 62.1%, specificity 92.0%, AUC 0.833).

Conclusion

Frequent exacerbators exhibited an increased level of NLR and a higher proportion of worse outcome during severe AECOPD. NLR is expected to be a promising predictive biomarker for the prognosis of severe AECOPD in frequent exacerbators.

COVID-19 and COPD: a narrative review of the basic science and clinical outcomes

The 2019 coronavirus disease (COVID-19) pandemic is caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Clinical outcomes, including mortality, are worse in males, older individuals and patients with comorbidities. COPD patients are included in shielding strategies due to their susceptibility to virus-induced exacerbations, compromised pulmonary function and high prevalence of associated comorbidities. Using evidence from basic science and cohort studies, this review addresses key questions concerning COVID-19 and COPD. First, are there mechanisms by which COPD patients are more susceptible to SARS-CoV-2 infection? Secondly, do inhaled corticosteroids offer protection against COVID-19? And, thirdly, what is the evidence regarding clinical outcomes from COVID-19 in COPD patients? This up-to-date review tackles some of the key issues which have significant impact on the long-term outlook for COPD patients in the context of COVID-19.

This up-to-date review tackles some of the key issues which have significant impact on the long-term outlook for COPD patients in the context of COVID-19https://bit.ly/36PKzEO

Management of chronic obstructive pulmonary disease: A review focusing on exacerbations

Purpose

Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality in the United States. Exacerbations— acute worsening of COPD symptoms—can be mild to severe in nature. Increased healthcare resource use is common among patients with frequent exacerbations, and exacerbations are a major cause of the high 30-day hospital readmission rates associated with COPD.

Summary

This review provides a concise overview of the literature regarding the impact of COPD exacerbations on both the patient and the healthcare system, the recommendations for pharmacologic management of COPD, and the strategies employed to improve patient care and reduce hospitalizations and readmissions. COPD exacerbations significantly impact patients’ health-related quality of life and disease progression; healthcare costs associated with severe exacerbation-related hospitalization range from $7,000 to $39,200. Timely and appropriate maintenance pharmacotherapy, particularly dual bronchodilators for maximizing bronchodilation, can significantly reduce exacerbations in patients with COPD. Additionally, multidisciplinary disease-management programs include pulmonary rehabilitation, follow-up appointments, aftercare, inhaler training, and patient education that can reduce hospitalizations and readmissions for patients with COPD.

Conclusion

Maximizing bronchodilation by the appropriate use of maintenance therapy, together with multidisciplinary disease-management and patient education programs, offers opportunities to reduce exacerbations, hospitalizations, and readmissions for patients with COPD.

Effect of acupoint application on T lymphocyte subsets in patients with chronic obstructive pulmonary disease: A meta-analysis

BACKGROUND

The development of chronic obstructive pulmonary disease (COPD) is related to the T lymphocyte mediated inflammatory immune response and immune imbalance. The purpose of this systematic review was to evaluate the clinical efficacy and safety of acupoint application on T lymphocyte subsets in patients with COPD.

METHODS

We searched CNKI, Wan fang, Chongqing VIP, China Biology Medicine disc, PubMed, the Cochrane Library, and EMBASE for studies published as of Oct. 31, 2019. All randomized controlled trials of acupoint application on COPD patients that met the inclusion criteria were included. The Cochrane bias risk assessment tool was used for literature evaluation. RevMan5.3 software was used for meta-analysis.

RESULTS

Eight studies (combined n = 524) qualified based on the inclusion criteria. Compared with routine treatment alone, acupoint application combined with routine treatment can significantly increase the T lymphocyte CD4/CD8 ratio (MD 0.12, 95% CI 0.03-0.21, P < .01, I = 49%), reduce CD8 T-cells (MD-0.99, 95% CI-1.70-0.28, P < .001, I = 37%), reduce the times of acute exacerbations (MD-0.28, 95% CI-0.35-0.21, P < .001, I = 0), and improve the clinical efficacy (MD 1.30, 95% CI 1.14-1.48, P < .001, I = 39%).

CONCLUSION

Acupoint application can improve the CD4/CD8 ratio and CD8 T-cells in patients with COPD and has an auxiliary effect in reducing the times of acute exacerbations and improving clinical efficacy.

Unique natural killer cell subpopulations are associated with exacerbation risk in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of death worldwide. COPD is frequently punctuated by acute exacerbations that are precipitated primarily by infections, which increase both morbidity and mortality and inflates healthcare costs. Despite the significance of exacerbations, little understanding of immune function in COPD exacerbations exists. Natural killer (NK) cells are important effectors of innate and adaptive immune responses to pathogens and NK cell function is altered in smokers and COPD. Using high-dimensional flow cytometry, we phenotyped peripheral blood NK cells from never smokers, smokers, and COPD patients and employed a non-supervised clustering algorithm to define and detect changes in NK cell populations. We identified greater than 1,000 unique NK cell subpopulations across patient groups and describe 13 altered NK populations in patients who experienced prior exacerbations. Based upon cluster sizes and associated fluorescence data, we generated a logistic regression model to predict patients with a history of exacerbations with high sensitivity and specificity. Moreover, highly enriched NK cell subpopulations implicated in the regression model exhibited enhanced effector functions as defined by in vitro cytotoxicity assays. These novel data reflect the effects of smoking and disease on peripheral blood NK cell phenotypes, provide insight into the potential immune pathophysiology of COPD exacerbations, and indicate that NK cell phenotyping may be a useful and biologically relevant marker to predict COPD exacerbations.

How Do Innate Immune Cells Contribute to Airway Remodeling in COPD Progression?

Recently, the therapeutic potential of immune-modulation during the progression of chronic obstructive pulmonary disease (COPD) has been attracting increasing interest. However, chronic inflammatory response has been over-simplified in descriptions of the mechanism of COPD progression. As a form of first-line airway defense, epithelial cells exhibit phenotypic alteration, and participate in epithelial layer disorganization, mucus hypersecretion, and extracellular matrix deposition. Dendritic cells (DCs) exhibit attenuated antigen-presenting capacity in patients with advanced COPD. Immature DCs migrate into small airways, where they promote a pro-inflammatory microenvironment and bacterial colonization. In response to damage-associated molecular patterns (DAMPs) in lung tissue affected by COPD, neutrophils are excessively recruited and activated, where they promote a proteolytic microenvironment and fibrotic repair in small airways. Macrophages exhibit decreased phagocytosis in the large airways, while they demonstrate high pro-inflammatory potential in the small airways, and mediate alveolar destruction and chronic airway inflammation. Natural killer T (NKT) cells, eosinophils, and mast cells also play supplementary roles in COPD progression; however, their cellular activities are not yet entirely clear. Overall, during COPD progression, “exhausted” innate immune responses can be observed in the large airways. On the other hand, the innate immune response is enhanced in the small airways. Approaches that inhibit the inflammatory cascade, chemotaxis, or the activation of inflammatory cells could possibly delay the progression of airway remodeling in COPD, and may thus have potential clinical significance.

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.

Immunodeficiency in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), characterized by progressive airway inflammation and irreversible airflow limitation, leads to serious decline in life quality. The acute exacerbation of COPD (AECOPD) results in high healthcare costs as well as a significant mortality rate. The most common cause of acute exacerbation is infection. Immune deficiency, which induces dysfunction of anti-infection, plays an important role in the pathogenesis of acute exacerbation. As described in this review, the immune dysfunction in patients with AECOPD can be a major focus of efforts to therapeutic strategy.