The formation and function of tertiary lymphoid follicles in chronic pulmonary inflammation

Lung mucosal immunity to NTHi vaccine antigens: Antibodies in sputum of chronic obstructive pulmonary disease patients

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory illness in older adults. A major cause of COPD-related morbidity and mortality is acute exacerbation of COPD (AECOPD). Bacteria in the lungs play a role in exacerbation development, and the most common pathogen is non-typeable Haemophilus influenzae (NTHi). A vaccine to prevent AECOPD containing NTHi surface antigens was tested in a clinical trial. This study measured IgG and IgA against NTHi vaccine antigens in sputum. Sputum samples from 40 COPD patients vaccinated with the NTHi vaccine were collected at baseline and 30 days after the second dose. IgG and IgA antibodies against the target antigens and albumin were analyzed in the sputum. We compared antibody signals before and after vaccination, analyzed correlation with disease severity and between sputum and serum samples, and assessed transudation. Antigen-specific IgG were absent before vaccination and present with high titers after vaccination. Antigen-specific IgA before and after vaccination were low but significantly different for two antigens. IgG correlated between sputum and serum, and between sputum and disease severity. Sputum albumin was higher in patients with severe COPD than in those with moderate COPD, suggesting changes in transudation played a role. We demonstrated that immunization with the NTHi vaccine induces antigen-specific antibodies in sputum. The correlation between IgG from sputum and serum and the presence of albumin in the sputum of severe COPD patients suggested transudation of antibodies from the serum to the lungs, although local IgG production could not be excluded.Clinical Trial Registration: NCT02075541.

Lymphatic Dysfunction Models an Autoimmune Emphysema Phenotype of Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous disease that is characterized by many clinical phenotypes. One such phenotype of COPD is defined by emphysema, pathogenic lung tertiary lymphoid organs (TLOs), and autoantibody production. We have previously shown that lymphatic dysfunction can cause lung TLO formation and lung injury in mice. We now sought to uncover whether underlying lymphatic dysfunction may be a driver of lung injury in cigarette smoke (CS)-induced COPD. We found that lung TLOs in mice with lymphatic dysfunction produce autoantibodies and are associated with a lymphatic endothelial cell subtype that expresses antigen presentation genes. Mice with underlying lymphatic dysfunction develop increased emphysema after CS exposure, with increased size and activation of TLOs. CS further increased autoantibody production in mice with lymphatic dysfunction. B-cell blockade prevented TLO formation and decreased lung injury after CS in mice with lymphatic dysfunction. Using tissue from human COPD patients, we also found evidence of a lymphatic gene signature that was specific to patients with emphysema and prominent TLOs compared to COPD patients without emphysema. Taken together, these data suggest that lymphatic dysfunction may underlie lung injury in a subset of COPD patients with an autoimmune emphysema phenotype.

Comparative Study of Ectopic Lymphoid Aggregates in Sheep and Murine Models of Bleomycin-Induced Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by excessive deposition of extracellular matrix in the interstitial lung parenchyma, often manifested by dyspnea and progressive loss of lung function. The role of inflammation in the pathogenesis of IPF is not well understood. This study evaluated the histopathological and inflammatory components of bleomycin-induced pulmonary fibrosis in mouse and sheep models, in terms of their ability to translate to the human IPF. Merino sheep (n = 8) were bronchoscopically administered with two bleomycin infusions, two weeks apart, into a caudal lung segment, with a saline (control) administered into a caudal segment in the opposite lung. Balb/c mice were twice intranasally instilled, one week apart, with either bleomycin (n = 7); or saline (control, n = 7). Lung samples were taken for the histopathological assessment 28 days in sheep and 21 days in mice after the first bleomycin administration. We observed tertiary lymphoid aggregates, in the fibrotic lung parenchyma of sheep, but not in mouse lung tissues exposed to bleomycin. B-cell and T-cell infiltration significantly increased in sheep lung tissues compared to mouse lung tissues due to bleomycin injury. Statistical analysis showed that the fibrotic score, fibrotic fraction, and tissue fraction significantly increased in sheep lung tissues compared to murine lung tissues. The presence of tertiary lymphoid aggregates in the lung parenchyma and increased infiltration of T-cells and B-cells, in the sheep model, may be useful for the future study of the underlying inflammatory disease mechanisms in the lung parenchyma of IPF patients.

[Population rearrangement of B-lymphocytes expressing chemokine receptors in patients with chronic obstructive pulmonary disease]

To date, there are no drugs that can prevent progressive destruction of lung tissue and small airway fibrosis in patients with chronic obstructive pulmonary disease (COPD). Therefore, molecular mechanisms of this disease are being studied. The aim of this study was to determine the chemokine receptor expression pattern of B-lymphocytes from peripheral blood and airways of patients with COPD. Peripheral blood was collected from 51 smokers with COPD, 21 healthy smokers, and 20 healthy non-smokers. Seven smokers with COPD and 7 healthy smokers were recruited to undergo bronchoscopy with bronchoalveolar lavage (BAL). The expression of chemokine receptors CCR5, CCR6, CCR7, CXCR3, CXCR4, and CXCR5 on the surface of blood and BAL B-lymphocytes was determined by flow cytometry. It was found that the percentage of blood B-lymphocytes expressing chemokine receptors CCR5 and CXCR3 was higher in smokers with COPD compared with healthy smokers and healthy non-smokers. The percentage of CD27⁺ B-cells expressing CCR5 and CXCR3 receptors exceeded the proportion of CD27⁻ B-lymphocytes expressing these receptors in peripheral blood of patients with COPD and healthy controls. In smoking patients with COPD, the percentage of BAL B-cells expressing receptors CCR5 and CXCR3 was also increased compared with healthy smokers. There were no differences in the percentage of B-lymphocytes expressing receptors CXCR4, CXCR5, CCR6, and CCR7 in both peripheral blood and BAL between smokers with COPD and healthy smokers. A greater percentage of CD27⁻ B-lymphocytes than CD27⁺ B-cells expressed receptors CXCR4, CXCR5, CCR6, and CCR7 in the peripheral blood of smokers with COPD and healthy controls. The results of this study indicate a modification in the chemokine receptor profile of B-lymphocytes in COPD.

CD19 and POU2AF1 are Potential Immune-Related Biomarkers Involved in the Emphysema of COPD: On Multiple Microarray Analysis

Purpose

Emphysema is the main cause of the progression of chronic obstructive pulmonary disease (COPD). This study aimed to identify the key genes involved in COPD-related emphysema.

Patients and Methods

GSE76925 was downloaded from Gene Expression Omnibus database. Protein–protein interaction networks of differentially expressed genes (DEGs) between control and COPD groups were constructed to identify hub genes using Cytoscape. Diagnostic performance of hub genes was evaluated using receiver operating characteristic analysis. Correlation analysis was performed to identify the key genes by analyzing the relationship between the hub genes and lung function and computed tomography (CT) indexes of emphysema. COPD patients were then divided into two groups based on the median expression of key genes and DEGs between these two groups were identified. Enrichment analysis of DEGs and correlation analysis between key genes and the infiltration of the immune cells were also analyzed. Finally, the role of key genes was evaluated in a lung tissues dataset (GSE47460) and a blood dataset (GSE76705). Additionally, the expression of key genes was validated by quantitative real-time polymerase chain reaction and immunohistochemistry.

Results

CD19 and POU2AF1 had diagnostic efficacy for COPD and were significantly correlated with lung function and CT indexes of emphysema. Enrichment and immune analyses revealed that CD19 and POU2AF1 were correlated with the B cells in COPD. These results were consistent in GSE47460. The expression of CD19 and POU2AF1 in blood was the opposite of that in lung tissues, and CD19 and POU2AF1 were both significantly upregulated in COPD lung tissues at both the mRNA and protein levels.

Conclusion

CD19 and POU2AF1 may serve as key regulators of emphysema and contribute to the progression of COPD by regulating the B-cell immunology. Targeting B cells may be a promising strategy for treating COPD.

Lung lymphatic thrombosis and dysfunction caused by cigarette smoke exposure precedes emphysema in mice

The lymphatic vasculature is critical for lung function, but defects in lymphatic function in the pathogenesis of lung disease is understudied. In mice, lymphatic dysfunction alone is sufficient to cause lung injury that resembles human emphysema. Whether lymphatic function is disrupted in cigarette smoke (CS)-induced emphysema is unknown. In this study, we investigated the effect of CS on lung lymphatic function. Analysis of human lung tissue revealed significant lung lymphatic thrombosis in patients with emphysema compared to control smokers that increased with disease severity. In a mouse model, CS exposure led to lung lymphatic thrombosis, decreased lymphatic drainage, and impaired leukocyte trafficking that all preceded the development of emphysema. Proteomic analysis demonstrated an increased abundance of coagulation factors in the lymph draining from the lungs of CS-exposed mice compared to control mice. In addition, in vitro assays demonstrated a direct effect of CS on lymphatic endothelial cell integrity. These data show that CS exposure results in lung lymphatic dysfunction and a shift in thoracic lymph towards a prothrombic state. Furthermore, our data suggest that lymphatic dysfunction is due to effects of CS on the lymphatic vasculature that precede emphysema. These studies demonstrate a novel component of CS-induced lung injury that occurs early in the pathogenesis of emphysema.

Pancreatic Cancer Chemotherapy Is Potentiated by Induction of Tertiary Lymphoid Structures in Mice

BACKGROUND AND AIMS

The presence of tertiary lymphoid structures (TLSs) may confer survival benefit to patients with pancreatic ductal adenocarcinoma (PDAC), in an otherwise immunologically inert malignancy. Yet, the precise role in PDAC has not been elucidated. Here, we aim to investigate the structure and role of TLSs in human and murine pancreatic cancer.

METHODS

Multicolor immunofluorescence and immunohistochemistry were used to fully characterize TLSs in human and murine (transgenic [KPC (KrasG12D, p53R172H, Pdx-1-Cre)] and orthotopic) pancreatic cancer. An orthotopic murine model was developed to study the development of TLSs and the effect of the combined chemotherapy and immunotherapy on tumor growth.

RESULTS

Mature, functional TLSs are not ubiquitous in human PDAC and KPC murine cancers and are absent in the orthotopic murine model. TLS formation can be induced in the orthotopic model of PDAC after intratumoral injection of lymphoid chemokines (CXCL13/CCL21). Coadministration of systemic chemotherapy (gemcitabine) and intratumoral lymphoid chemokines into orthotopic tumors altered immune cell infiltration ,facilitating TLS induction and potentiating antitumor activity of chemotherapy. This resulted in significant tumor reduction, an effect not achieved by either treatment alone. Antitumor activity seen after TLS induction is associated with B cell-mediated dendritic cell activation.

CONCLUSIONS

This study provides supportive evidence that TLS induction may potentiate the antitumor activity of chemotherapy in a murine model of PDAC. A detailed understanding of TLS kinetics and their induction, owing to multiple host and tumor factors, may help design personalized therapies harnessing the potential of immune-oncology.

Enhanced lung inflammatory response in whole-body compared to nose-only cigarette smoke-exposed mice

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by a progressive and abnormal inflammatory response in the lungs, mainly caused by cigarette smoking. Animal models exposed to cigarette smoke (CS) are used to mimic human COPD but the use of different CS protocols makes it difficult to compare the immunological and structural consequences of using a nose-only or whole-body CS exposure system. We hypothesized that when using a standardized CS exposure protocol based on particle density and CO (carbon monoxide) levels, the whole-body CS exposure system would generate a more severe inflammatory response than the nose-only system, due to possible sensitization by uptake of CS-components through the skin or via grooming.

METHODS

In this study focusing on early COPD, mice were exposed twice daily 5 days a week to CS either with a nose-only or whole-body exposure system for 14 weeks to assess lung function, remodeling and inflammation.

RESULTS

At sacrifice, serum cotinine levels were significantly higher in the whole-body (5.3 (2.3-6.9) ng/ml) compared to the nose-only ((2.0 (1.8-2.5) ng/ml) exposure system and controls (1.0 (0.9-1.0) ng/ml). Both CS exposure systems induced a similar degree of lung function impairment, while inflammation was more severe in whole body exposure system. Slightly more bronchial epithelial damage, mucus and airspace enlargement were observed with the nose-only exposure system. More lymphocytes were present in the bronchoalveolar lavage (BAL) and lymph nodes of the whole-body exposure system while enhanced IgA and IgG production was found in BAL and to a lesser extent in serum with the nose-only exposure system.

CONCLUSION

The current standardized CS-exposure protocol resulted in a higher internal load of serum cotinine in the whole-body exposure system, which was associated with more inflammation. However, both exposure systems resulted in a similar lung function impairment. Data also highlighted differences between the two models in terms of lung inflammation and remodelling, and potential sensitization to CS. Researchers should be aware of these differences when designing their future studies for an early intervention in COPD.

Monocyte-derived dendritic cells link localized secretory IgA deficiency to adaptive immune activation in COPD

Although activation of adaptive immunity is a common pathological feature of chronic obstructive pulmonary disease (COPD), particularly during later stages of the disease, the underlying mechanisms are poorly understood. In small airways of COPD patients, we found that localized disruption of the secretory immunoglobulin A (SIgA)-containing mucosal immunobarrier correlated with lymphocyte accumulation in airway walls and development of tertiary lymphoid structures (TLS) around small airways. In SIgA-deficient mice, we observed bacterial invasion into the airway epithelial barrier with lymphocytic infiltration and TLS formation, which correlated with the progression of COPD-like pathology with advanced age. Depletion of either CD4⁺ or CD8⁺ T lymphocytes reduced the severity of emphysema in SIgA-deficient mice, indicating that adaptive immune activation contributes to progressive lung destruction. Further studies revealed that lymphocyte infiltration into the lungs of SIgA-deficient mice was dependent on monocyte-derived dendritic cells (moDCs), which were recruited through a CCR2-dependent mechanism in response to airway bacteria. Consistent with these results, we found that moDCs were increased in lungs of COPD patients, along with CD4⁺ and CD8⁺ effector memory T cells. Together, these data indicate that endogenous bacteria in SIgA-deficient airways orchestrate a persistent and pathologic T lymphocyte response through monocyte recruitment and moDC differentiation.

Lymphatic Proliferation Ameliorates Pulmonary Fibrosis after Lung Injury

Despite many reports about pulmonary blood vessels in lung fibrosis, the contribution of lymphatics to fibrosis is unknown. We examined the mechanism and consequences of lymphatic remodeling in mice with lung fibrosis after bleomycin injury or telomere dysfunction. Widespread lymphangiogenesis was observed after bleomycin treatment and in fibrotic lungs of prospero homeobox 1-enhanced green fluorescent protein (Prox1-EGFP) transgenic mice with telomere dysfunction. In loss-of-function studies, blocking antibodies revealed that lymphangiogenesis 14 days after bleomycin treatment was dependent on vascular endothelial growth factor (Vegf) receptor 3 signaling, but not on Vegf receptor 2. Vegfc gene and protein expression increased specifically. Extensive extravasated plasma, platelets, and macrophages at sites of lymphatic growth were potential sources of Vegfc. Lymphangiogenesis peaked at 14 to 28 days after bleomycin challenge, was accompanied by doubling of chemokine (C-C motif) ligand 21 in lung lymphatics and tertiary lymphoid organ formation, and then decreased as lung injury resolved by 56 days. In gain-of-function studies, expansion of the lung lymphatic network by transgenic overexpression of Vegfc in club cell secretory protein (CCSP)/VEGF-C mice reduced macrophage accumulation and fibrosis and accelerated recovery after bleomycin treatment. These findings suggest that lymphatics have an overall protective effect in lung injury and fibrosis and fit with a mechanism whereby lung lymphatic network expansion reduces lymph stasis and increases clearance of fluid and cells, including profibrotic macrophages.

Tertiary lymphoid structure related B-cell IgE isotype switching and secondary lymphoid organ linked IgE production in mouse allergy model

Background

Numerous data obtained by different research laboratories indicate that specific IgE production is triggered independently of specific IgG or IgA ones and so it is not linked to fully matured germinal centers formation in the secondary lymphoid organs. The aim of this study was to clarify whether specific IgE production is triggered by low antigen doses administrated in tertiary tissues enriched by lymphoid structures.

Methods

Ovalbumin (OVA) in different doses (100 ng to 10 μg) was administrated three times a week for 4–5 weeks intraperitoneally (i.p.) or subcutaneously (s.c.) to female BALB/c mice in the wither region which is enriched in fat-associated lymphoid clusters or in the foot pad region not containing them.

Results

OVA-specific IgE was predominantly induced by low but not high antigen doses and only after immunization into the withers. IgE isotype switching was triggered exclusively in the withers adipose tissue but not in the regional lymph nodes while mature IgE expressing cells were observed both in the withers and lymph nodes. Anti-proliferative genotoxic stress inducing drugs shifted the balance from IgG1 towards IgE production.

Conclusions

Tertiary lymphoid structures possess unique environment where B-cell antibody isotype switching to IgE predominantly occurs. This phenomenon is partially explained by hampered proliferation of B-cells in these structures.

Innate Lymphoid Cells of the Lung

Although, as the major organ of gas exchange, the lung is considered a nonlymphoid organ, an interconnected network of lung-resident innate cells, including epithelial cells, dendritic cells, macrophages, and natural killer cells is crucial for its protection. These cells provide defense against a daily assault by airborne bacteria, viruses, and fungi, as well as prevent the development of cancer, allergy, and the outgrowth of commensals. Our understanding of this innate immune environment has recently changed with the discovery of a family of innate lymphoid cells (ILCs): ILC1s, ILC2s, and ILC3s. All lack adaptive antigen receptors but can provide a substantial and rapid source of IFN-γ, IL-5 and IL-13, and IL-17A or IL-22, respectively. Their ability to afford immediate protection to the lung and to influence subsequent adaptive immune responses highlights the importance of understanding ILC-regulated immunity for the design of future therapeutic interventions.

Ectopic Lymphoid Organs and Immune-Mediated Diseases: Molecular Basis for Pharmacological Approaches

Chronic inflammation is the result a persistent increase in the expression of several proinflammatory pathways with impaired inflammatory resolution. Ectopic lymphoid organs (ELOs), untypical lymphoid annexes, emerge during chronic inflammation and contribute to the physiopathology of chronic inflammatory disorders. This review discusses the pathophysiological role of ELOs in the progression of immune-mediated inflammatory diseases (IMIDs), including multiple sclerosis (MS), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), atherosclerosis, and Sjögren syndrome (SSj). The molecular pathways underlying the emergence of ELOs are of interest for the development of novel pharmacological approaches for the management of chronic inflammatory diseases.

Chronic lung allograft dysfunction post-lung transplantation: The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome

Chronic lung allograft dysfunction (CLAD) following lung transplantation limits long-term survival considerably. The main reason for this is a lack of knowledge regarding the pathological condition and the establishment of treatment. The consensus statement from the International Society for Heart and Lung Transplantation on CLAD in 2019 classified CLAD into two main phenotypes: Bronchiolitis obliterans syndrome and restrictive allograft syndrome. Along with this clear classification, further exploration of the mechanisms and the development of appropriate prevention and treatment strategies for each phenotype are desired. In this review, we summarize the new definition of CLAD and update and summarize the existing knowledge on the underlying mechanisms of bronchiolitis obliterans syndrome and restrictive allograft syndrome, which have been elucidated from clinicopathological observations and animal experiments worldwide.

Rituximab Monotherapy for Common Variable Immune Deficiency-Associated Granulomatous-Lymphocytic Interstitial Lung Disease

Patients with common variable immunodeficiency (CVID) can develop granulomatous-lymphocytic interstitial lung disease (GLILD), which is associated with increased morbidity and mortality. Treating GLILD is a significant challenge because it is rare and can be pathologically heterogeneous. Here we describe two cases of patients with CVID-associated GLILD with biopsies demonstrating loosely organized tertiary lymphoid structures (TLSs). Based on the pivotal role that B cells play in TLS initiation and maintenance, we hypothesized that using rituximab monotherapy for B-cell depletion alone would be sufficient for the disruption of the pathologic process underlying GLILD. These two cases demonstrate that adapting a strategy of B cell depletion monotherapy may be effective in TLS-associated conditions such as GLILD.

Small Airway Disease: A Step Closer to Etiology-Based Classification of Bronchiolitis

Three major histologic patterns of bronchiolitis: obliterative bronchiolitis, follicular bronchiolitis, and diffuse panbronchiolitis, are reviewed in detail. These distinct patterns of primary bronchiolar injury provide a useful starting point for formulating a differential diagnosis and considering possible causes. In support of the aim toward a cause-based classification system of small airway disease, a simple diagnostic algorithm is provided for further subclassification of the above 3 bronchiolitis patterns according to the major associated etiologic subgroups.

Oral cancer-associated tertiary lymphoid structures: gene expression profile and prognostic value

Tertiary lymphoid structure (TLS) provides a local and critical microenvironment for both cellular and humoral immunity and supports effective antigen presentation and lymphocyte activation. However, the gene expression profile and prognostic significance of TLS in oral cancer remain largely unrevealed. In this study, we found the presence of both intratumoral and peritumoral TLSs in a series of 65 patients with oral cancer treated by surgical resection, with positive detection rates of 33.8 and 75.4%, respectively. The presence of intratumoral TLSs, but not peritumoral TLSs, was significantly associated with decreased P53 and Ki67 scores (P = 0·027 and 0·047, respectively). The survival analyses revealed that oral cancer patients with higher grades of TLSs was associated with improved disease-free survival (DFS) and overall survival (OS) (P = 0·037 and 0·031, respectively). Gene expression profiling analysis of the cytokines and chemokines responsible for lymph-node neogenesis identified a three-up-regulated-gene set, i.e. IL7, LTB and CXCL13, which was shown to be correlated with human oral cancer-associated TLSs. This study provides a framework for better understanding of oral cancer-associated TLSs and for delineating future innovative prognostic biomarkers and immune therapeutic strategies for oral cancer.

Immune-Modulation in Chronic Obstructive Pulmonary Disease: Current Concepts and Future Strategies

Chronic obstructive pulmonary disease (COPD) is caused by the chronic inhalation of toxic particles and gases that are primarily but not exclusively derived from cigarette smoke that may be either actively or passively inhaled, which initiates a persistent innate and adaptive immune response in the lung. This immune response is associated with an aberrant tissue repair and remodeling process that results in varying degrees of chronic inflammation with excess production of mucus in the central airways and permanent destruction of the smaller conducting airways and gas exchanging surface in the peripheral lung. Currently, the primary aims of treatment in COPD are bronchodilation (inhaled short- and long-acting β-agonist and antimuscarinic therapies), to control symptoms and nonspecific broad-acting anti-inflammatory agents (inhaled and oral corticosteroids, phosphor-di-esterase inhibitors, and macrolides). That provide symptomatic relief but have little or no impact on either disease progression or mortality. As our understanding of the immune pathogenesis of the COPD improves, available immune modulation therapies have the potential to alter or interfere with damaging immune pathways, thereby slowing relentless progression of lung tissue destruction. The purpose of this brief review is to discuss our current understanding of the immune pathogenesis of both the airways and parenchymal injury as well as the dysfunctional tissue repair process to propose immune modulating interventions in an attempt to stabilize or return these pathological changes to their normal state. The ultimate goal of the immune modulation therapy is to improve both morbidity and mortality associated with COPD.

T-cell immunology of the lung: maintaining the balance between host defence and immune pathology

Respiratory immunology poses the dual questions of how to grapple with lung infection as one of the greatest unmet global health needs of our time, while also dealing with the growing challenge posed by chronic diseases of excessive or inappropriate lung inflammation and immunity, such as chronic obstructive lung disease and asthma. These separate branches of pulmonary research are linked by the clear observation that, in a tissue as fragile as the lung, protection from microbial attack may come at the cost of chronic inflammatory damage. A number of recent studies have considered specific aspects of this double-edged sword, including the diversity of responses to fungal exposure, sources and consequences of interleukin-17 immunity, and the role of tertiary lymphoid follicles in the lung.

Lymphatic impairment leads to pulmonary tertiary lymphoid organ formation and alveolar damage

The lung is a specialized barrier organ that must tightly regulate interstitial fluid clearance and prevent infection in order to maintain effective gas exchange. Lymphatic vessels are important for these functions in other organs, but their roles in the lung have not been fully defined. In the present study, we addressed how the lymphatic vasculature participates in lung homeostasis. Studies using mice carrying a lymphatic reporter allele revealeded that, in contrast to other organs, lung lymphatic collecting vessels lack smooth muscle cells entirely, suggesting that forward lymph flow is highly dependent on movement and changes in pressure associated with respiration. Functional studies using CLEC2-deficient mice in which lymph flow is impaired due to loss of lympho-venous hemostasis or using inducible lung-specific ablation of lymphatic endothelial cells in a lung transplant model revealeded that loss of lymphatic function leads to an inflammatory state characterized by the formation of tertiary lymphoid organs (TLOs). In addition, impaired lymphatic flow in mice resulteds in hypoxia and features of lung injury that resemble emphysema. These findings reveal both a lung-specific mechanism of lymphatic physiology and a lung-specific consequence of lymphatic dysfunction that may contribute to chronic lung diseases that arise in association with TLO formation.

Increased frequency of CCR7+CD4+ T cells from patients with primary Sjögren's syndrome: An indicator of disease activity rather than of damage severity

Expression of CCR7 on T cells has been reported to be associated with the lymphocytic migration and infiltration, which is recognized as a vital part of the pathogenesis of Primary Sjögren's syndrome (pSS). Here, we compared the expression of CCR7 on CD4+T cells between pSS patients and control groups, including healthy donors (HD) and patients with systemic lupus erythematosus (SLE) and examined correlations with disease activity and damage severity, which were evaluated by EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) and Sjogren's Syndrome Disease Damage Index (SSDDI), respectively. Peripheral blood mononuclear Cells (PBMC) were obtained from patients and controls and expressions of CCR7 were evaluated by flow cytometry. CCR7 was selectively and frequently expressed on CD4⁺T cells, but less on CD8⁺ T cells of patients with pSS. In contrast, this phenomenon was neither seen in normal subjects nor in patients with SLE. The expression level of CCR7 in the peripheral blood CD4⁺ T cells is closely correlated with ESSDAI, but not SSDDI. Correspondently, the chemotactic index (CI) of CD4⁺T cells was higher than CD8⁺T cells in patients with pSS. Furthermore, the CI of CD4⁺T cells is also higher than that of other controls, which is correlated with ESSDAI. All the findings suggested that CCR7 might play an important role in the development of pSS by mediating the migration of CD4⁺cells. Thus, the expression of CCR7 in CD4⁺ T cells is probably a useful biomarker to evaluate and monitor disease activity. CCR7 can also potentially be a novel target for the therapy of pSS.

Perivascular adipose tissue inflammation in vascular disease

Perivascular adipose tissue (PVAT) plays a critical role in the pathogenesis of cardiovascular disease. In vascular pathologies, perivascular adipose tissue increases in volume and becomes dysfunctional, with altered cellular composition and molecular characteristics. PVAT dysfunction is characterized by its inflammatory character, oxidative stress, diminished production of vaso-protective adipocyte-derived relaxing factors and increased production of paracrine factors such as resistin, leptin, cytokines (IL-6 and TNF-α) and chemokines [RANTES (CCL5) and MCP-1 (CCL2)]. These adipocyte-derived factors initiate and orchestrate inflammatory cell infiltration including primarily T cells, macrophages, dendritic cells, B cells and NK cells. Protective factors such as adiponectin can reduce NADPH oxidase superoxide production and increase NO bioavailability in the vessel wall, while inflammation (e.g. IFN-γ or IL-17) induces vascular oxidases and eNOS dysfunction in the endothelium, vascular smooth muscle cells and adventitial fibroblasts. All of these events link the dysfunctional perivascular fat to vascular dysfunction. These mechanisms are important in the context of a number of cardiovascular disorders including atherosclerosis, hypertension, diabetes and obesity. Inflammatory changes in PVAT's molecular and cellular responses are uniquely different from classical visceral or subcutaneous adipose tissue or from adventitia, emphasizing the unique structural and functional features of this adipose tissue compartment. Therefore, it is essential to develop techniques for monitoring the characteristics of PVAT and assessing its inflammation. This will lead to a better understanding of the early stages of vascular pathologies and the development of new therapeutic strategies focusing on perivascular adipose tissue.

LINKED ARTICLES

This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.20/issuetoc.

Noninvasive vaccination as a casus belli to redeem vaccine value in the face of anti-vaccine movements

Formidable anti-vaccine movements have been growing as a menace to disrupt beneficial vaccine programs. Although the vaccination-associated adverse effects commonly perceived by vaccine resisters usually represent over-reactions to rare manifestations, converging evidence shows that vaccination-associated health threats could be pervasive when systemic inflammation is considered as a side effect that oozes over time. An anti-vaccine movement thus may not be so unfounded even though the myriad cascades triggered by systemic inflammation have not been brought to a clear focus during any anti-vaccine campaign. Since both pro- and anti-vaccine groups are acting on the same primal impulse - "keep people healthy," reconciliation between the two warring factions should be achievable on a palatable trend that fosters the development of noninvasive vaccines which tend to induce local and transient inflammation along the interface with diminished potential to percolate through internal organs.

Noninvasive vaccination as a casus belli to redeem vaccine value in the face of anti-vaccine movements

Formidable anti-vaccine movements have been growing as a menace to disrupt beneficial vaccine programs. Although the vaccination-associated adverse effects commonly perceived by vaccine resisters usually represent over-reactions to rare manifestations, converging evidence shows that vaccination-associated health threats could be pervasive when systemic inflammation is considered as a side effect that oozes over time. An anti-vaccine movement thus may not be so unfounded even though the myriad cascades triggered by systemic inflammation have not been brought to a clear focus during any anti-vaccine campaign. Since both pro- and anti-vaccine groups are acting on the same primal impulse - "keep people healthy," reconciliation between the two warring factions should be achievable on a palatable trend that fosters the development of noninvasive vaccines which tend to induce local and transient inflammation along the interface with diminished potential to percolate through internal organs.