| 1. |
- Cagigi, Alberto, et al.
(author)
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Airway antibodies emerge according to COVID-19 severity and wane rapidly but reappear after SARS-CoV-2 vaccination
- 2021
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In: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 6:22
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Journal article (peer-reviewed)abstract
- Understanding the presence and durability of antibodies against SARS-CoV-2 in the airways is required to provide insights into the ability of individuals to neutralize the virus locally and prevent viral spread. Here, we longitudinally assessed both systemic and airway immune responses upon SARS-CoV-2 infection in a clinically well-characterized cohort of 147 infected individuals representing the full spectrum of COVID-19 severity, from asymptomatic infection to fatal disease. In addition, we evaluated how SARS-CoV-2 vaccination influenced the antibody responses in a subset of these individuals during convalescence as compared with naive individuals. Not only systemic but also airway antibody responses correlated with the degree of COVID-19 disease severity. However, although systemic IgG levels were durable for up to 8 months, airway IgG and IgA declined significantly within 3 months. After vaccination, there was an increase in both systemic and airway antibodies, in particular IgG, often exceeding the levels found during acute disease. In contrast, naive individuals showed low airway antibodies after vaccination. In the former COVID-19 patients, airway antibody levels were significantly elevated after the boost vaccination, highlighting the importance of prime and boost vaccinations for previously infected individuals to obtain optimal mucosal protection.
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| 2. |
- Baharom, Faezzah, et al.
(author)
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Human lung dendritic cells : spatial distribution and phenotypic identification in endobronchial biopsies using immunohistochemistry and flow cytometry
- 2017
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In: Journal of Visualized Experiments. - Cambridge : MyJoVE Corp.. - 1940-087X. ; :119
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Journal article (peer-reviewed)abstract
- The lungs are constantly exposed to the external environment, which in addition to harmless particles, also contains pathogens, allergens, and toxins. In order to maintain tolerance or to induce an immune response, the immune system must appropriately handle inhaled antigens. Lung dendritic cells (DCs) are essential in maintaining a delicate balance to initiate immunity when required without causing collateral damage to the lungs due to an exaggerated inflammatory response. While there is a detailed understanding of the phenotype and function of immune cells such as DCs in human blood, the knowledge of these cells in less accessible tissues, such as the lungs, is much more limited, since studies of human lung tissue samples, especially from healthy individuals, are scarce. This work presents a strategy to generate detailed spatial and phenotypic characterization of lung tissue resident DCs in healthy humans that undergo a bronchoscopy for the sampling of endobronchial biopsies. Several small biopsies can be collected from each individual and can be subsequently embedded for ultrafine sectioning or enzymatically digested for advanced flow cytometric analysis. The outlined protocols have been optimized to yield maximum information from small tissue samples that, under steady-state conditions, contain only a low frequency of DCs. While the present work focuses on DCs, the methods described can directly be expanded to include other (immune) cells of interest found in mucosal lung tissue. Furthermore, the protocols are also directly applicable to samples obtained from patients suffering from pulmonary diseases where bronchoscopy is part of establishing the diagnosis, such as chronic obstructive pulmonary disease (COPD), sarcoidosis, or lung cancer.
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| 3. |
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| 5. |
- Evren, Elza, et al.
(author)
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Distinct developmental pathways from blood monocytes generate human lung macrophage diversity
- 2021
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In: Immunity. - : Elsevier. - 1074-7613 .- 1097-4180. ; 51, s. 35-35
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Journal article (peer-reviewed)abstract
- The study of human macrophages and their ontogeny is an important unresolved issue. Here, we use a humanized mouse model expressing human cytokines to dissect the development of lung macrophages from human hematopoiesis in vivo. Human CD34+ hematopoietic stem and progenitor cells (HSPCs) generated three macrophage populations, occupying separate anatomical niches in the lung. Intravascular cell labeling, cell transplantation, and fate-mapping studies established that classical CD14+ blood monocytes derived from HSPCs migrated into lung tissue and gave rise to human interstitial and alveolar macrophages. In contrast, non-classical CD16+ blood monocytes preferentially generated macrophages resident in the lung vasculature (pulmonary intravascular macrophages). Finally, single-cell RNA sequencing defined intermediate differentiation stages in human lung macrophage development from blood monocytes. This study identifies distinct developmental pathways from circulating monocytes to lung macrophages and reveals how cellular origin contributes to human macrophage identity, diversity, and localization in vivo.
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| 6. |
- Lepzien, Rico, et al.
(author)
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Monocytes in sarcoidosis are potent tumour necrosis factor producers and predict disease outcome
- 2021
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In: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 58:1
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Journal article (peer-reviewed)abstract
- Background Pulmonary sarcoidosis is an inflammatory disease characterised by granuloma formation and heterogeneous clinical outcome. Tumour necrosis factor (TNF) is a pro-inflammatory cytokine contributing to granuloma formation and high levels of TNF have been shown to associate with progressive disease. Mononuclear phagocytes (MNPs) are potent producers of TNF and highly responsive to inflammation. In sarcoidosis, alveolar macrophages have been well studied. However, MNPs also include monocytes/monocyte-derived cells and dendritic cells, which are poorly studied in sarcoidosis, despite their central role in inflammation.Objective To determine the role of pulmonary monocyte-derived cells and dendritic cells during sarcoidosis.Methods We performed in-depth phenotypic, functional and transcriptomic analysis of MNP subsets from blood and bronchoalveolar lavage (BAL) fluid from 108 sarcoidosis patients and 30 healthy controls. We followed the clinical development of patients and assessed how the repertoire and function of MNP subsets at diagnosis correlated with 2-year disease outcome.Results Monocytes/monocyte-derived cells were increased in blood and BAL of sarcoidosis patients compared to healthy controls. Interestingly, high frequencies of blood intermediate monocytes at time of diagnosis associated with chronic disease development. RNA sequencing analysis showed highly inflammatory MNPs in BAL of sarcoidosis patients. Furthermore, frequencies of BAL monocytes/ monocyte-derived cells producing TNF without exogenous stimulation at time of diagnosis increased in patients that were followed longitudinally. In contrast to alveolar macrophages, the frequency of TNFproducing BAL monocytes/monocyte-derived cells at time of diagnosis was highest in sarcoidosis patients that developed progressive disease.Conclusion Our data show that pulmonary monocytes/monocyte-derived cells are highly inflammatory and can be used as a predictor of disease outcome in sarcoidosis patients.
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| 7. |
- Lepzien, Rico, et al.
(author)
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Mononuclear phagocytes in lungs, lymph nodes and blood of sarcoidosis patients
- 2018
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In: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 52
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Journal article (other academic/artistic)abstract
- Introduction: Sarcoidosis is characterized by granuloma formation primarily in the lung and lung-draining lymph nodes (LN). The disease can present with an acute onset (usually Löfgren’s syndrome (LS)) or a gradual onset (non-LS). Mononuclear phagocytes (MNPs) - macrophages, monocytes and dendritic cells (DC) - are likely critical in sarcoidosis as they initiate and maintain T cell activation and contribute to granuloma formation by production of cytokines. MNPs in lung tissue and LN are poorly studied in both, non-LS and LS sarcoidosis patients.Aim: To characterise the distribution and phenotype of MNPs in BAL, endobronchial biopsies (EBB), LN sampled by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and blood from the same non-LS or LS sarcoidosis patients.Results: We identified MNPs from all four anatomical compartments in non-LS (n=7) and LS (n=4) sarcoidosis patients. Blood, BAL and LN contained all MNP subsets while EBB only harboured one of three monocyte subsets. Frequencies, maturation and migratory status were different between the compartments as well as between non-LS and LS patients. Our results suggest heterogeneity in distribution and function of MNPs within organs typically affected in sarcoidosis and their potential involvement in the disease course.Conclusions: We show that cells from BAL fluid do not necessarily reflect cells from EBB, a tissue primarily affected by granuloma formation. Our work provides a foundation for future investigations of MNPs in non-LS and LS sarcoidosis patients, allowing improved stratification to identify patients at risk of developing severe disease and provide early treatment to slow down disease progression.
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| 8. |
- Lepzien, Rico, et al.
(author)
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Pulmonary and blood dendritic cells from sarcoidosis patients more potently induce IFNγ-producing Th1 cells compared with monocytes
- 2022
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In: Journal of Leukocyte Biology. - 0741-5400 .- 1938-3673. ; 111:4, s. 857-866
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Journal article (peer-reviewed)abstract
- Sarcoidosis is a systemic inflammatory disease mainly affecting the lungs. The hallmark of sarcoidosis are granulomas that are surrounded by activated T cells, likely targeting the disease-inducing antigen. IFNγ-producing Th1 and Th17.1 T cells are elevated in sarcoidosis and associate with disease progression. Monocytes and dendritic cells (DCs) are antigen-presenting cells (APCs) and required for T cell activation. Several subsets of monocytes and DCs with different functions were identified in sarcoidosis. However, to what extent different monocyte and DC subsets can support activation and skewing of T cells in sarcoidosis is still unclear. In this study, we performed a transcriptional and functional side-by-side comparison of sorted monocytes and DCs from matched blood and bronchoalveolar lavage (BAL) fluid of sarcoidosis patients. Transcriptomic analysis of all subsets showed upregulation of genes related to T cell activation and antigen presentation in DCs compared with monocytes. Allogeneic T cell proliferation was higher after coculture with monocytes and DCs from blood compared with BAL and DCs induced more T cell proliferation compared with monocytes. After coculture, proliferating T cells showed high expression of the transcription factor Tbet and IFNγ production. We also identified Tbet and RORγt coexpressing T cells that mainly produced IFNγ. Our data show that DCs rather than monocytes from sarcoidosis patients have the ability to activate and polarize T cells towards Th1 and Th17.1 cells. This study provides a useful in vitro tool to better understand the contribution of monocytes and DCs to T cell activation and immunopathology in sarcoidosis.
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| 9. |
- Li, Shuijie, et al.
(author)
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Impaired oxygen-sensitive regulation of mitochondrial biogenesis within the von Hippel–Lindau syndrome
- 2022
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In: Nature Metabolism. - : Nature Publishing Group. - 2522-5812. ; 4:6, s. 739-758
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Journal article (peer-reviewed)abstract
- Mitochondria are the main consumers of oxygen within the cell. How mitochondria sense oxygen levels remains unknown. Here we show an oxygen-sensitive regulation of TFAM, an activator of mitochondrial transcription and replication, whose alteration is linked to tumours arising in the von Hippel–Lindau syndrome. TFAM is hydroxylated by EGLN3 and subsequently bound by the von Hippel–Lindau tumour-suppressor protein, which stabilizes TFAM by preventing mitochondrial proteolysis. Cells lacking wild-type VHL or in which EGLN3 is inactivated have reduced mitochondrial mass. Tumorigenic VHL variants leading to different clinical manifestations fail to bind hydroxylated TFAM. In contrast, cells harbouring the Chuvash polycythaemia VHLR200W mutation, involved in hypoxia-sensing disorders without tumour development, are capable of binding hydroxylated TFAM. Accordingly, VHL-related tumours, such as pheochromocytoma and renal cell carcinoma cells, display low mitochondrial content, suggesting that impaired mitochondrial biogenesis is linked to VHL tumorigenesis. Finally, inhibiting proteolysis by targeting LONP1 increases mitochondrial content in VHL-deficient cells and sensitizes therapy-resistant tumours to sorafenib treatment. Our results offer pharmacological avenues to sensitize therapy-resistant VHL tumours by focusing on the mitochondria.
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