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.

Activation of immune cell proteasomes in peripheral blood of smokers and COPD patients: implications for therapy.

BACKGROUND: Immune cells contain a specialised type of proteasome, i.e. the immunoproteasome, which is required for intracellular protein degradation. Immunoproteasomes are key regulators of immune cell differentiation, inflammatory activation and autoimmunity. Immunoproteasome function in peripheral immune cells might be altered by smoking and in chronic obstructive pulmonary disease (COPD), thereby affecting immune cell responses. METHODS: We analysed the expression and activity of proteasome complexes in peripheral blood mononuclear cells (PBMCs) isolated from healthy male young smokers as well as from patients with severe COPD and compared them with matching controls. RESULTS: Proteasome expression was upregulated in COPD patients as assessed by quantitative reverse transcriptase-PCR and mass spectrometry-based proteomic analysis. Proteasome activity was quantified using activity-based probes and native gel analysis. We observed distinct activation of immunoproteasomes in the peripheral blood cells of young male smokers and severely ill COPD patients. Native gel analysis and linear regression modelling confirmed robust activation and elevated assembly of 20S proteasomes, which correlated significantly with reduced lung function parameters in COPD patients. The immunoproteasome was distinctly activated in COPD patients upon inflammatory cytokine stimulation of PBMCs in vitro. Inhibition of the immunoproteasome reduced pro-inflammatory cytokine expression in COPD-derived blood immune cells. CONCLUSIONS: Given the crucial role of chronic inflammatory signalling and the emerging involvement of autoimmune responses in COPD, therapeutic targeting of the immunoproteasome might represent a novel therapeutic concept for COPD.

CX3CR1-fractalkine axis drives kinetic changes of monocytes in fibrotic interstitial lung diseases.

Circulating immune cell populations have been shown to contribute to interstitial lung disease (ILD). In this study, we analysed circulating and lung resident monocyte populations, and assessed their phenotype and recruitment from the blood to the lung in ILD. Flow cytometry analysis of blood samples for quantifying circulating monocytes was performed in 105 subjects: 83 with ILD (n=36, n=28 and n=19 for nonspecific interstitial pneumonia, hypersensitivity pneumonitis and connective-tissue disease-associated ILD, respectively), as well as 22 controls. Monocyte localisation and abundance were assessed using immunofluorescence and flow cytometry of lung tissue. Monocyte populations were cultured either alone or with endothelial cells to assess fractalkine-dependent transmigration pattern. We show that circulating classical monocytes (CM) were increased in ILD compared with controls, while nonclassical monocytes (NCM) were decreased. CM abundance correlated inversely with lung function, while NCM abundance correlated positively. Both CCL2 and CX3CL1 concentrations were increased in plasma and lungs of ILD patients. Fractalkine co-localised with ciliated bronchial epithelial cells, thereby creating a chemoattractant gradient towards the lung. Fractalkine enhanced endothelial transmigration of NCM in ILD samples only. Immunofluorescence, as well as flow cytometry, showed an increased presence of NCM in fibrotic niches in ILD lungs. Moreover, NCM in the ILD lungs expressed increased CX3CR1, M2-like and phagocytic markers. Taken together, our data support that in ILD, fractalkine drives the migration of CX3CR1+ NCM to the lungs, thereby perpetuating the local fibrotic process.

Survival and course of lung function in the presence or absence of antifibrotic treatment in patients with idiopathic pulmonary fibrosis: long-term results of the INSIGHTS-IPF registry.

OBJECTIVE: There is a paucity of observational data on antifibrotic therapy for idiopathic pulmonary fibrosis (IPF). We aimed to assess the course of disease of IPF patients with and without antifibrotic therapy under real-life conditions. METHODS: We analysed data from a non-interventional, prospective cohort study of consecutively enrolled IPF patients from 20 interstitial lung disease expert centres in Germany. Data quality was ensured by automated plausibility checks, on-site monitoring, and source data verification. Propensity scores were applied to account for known differences in baseline characteristics between patients with and without antifibrotic therapy. RESULTS: Among the 588 patients suitable for analysis, the mean±sd age was 69.8±9.1 years, and 81.0% were male. The mean±sd duration of disease since diagnosis was 1.8±3.4 years. The mean±sd value at baseline for forced vital capacity (FVC) and diffusion capacity (D LCO) were 68.6±18.8% predicted and 37.8±18.5% predicted, respectively. During a mean±sd follow-up of 1.2±0.7 years, 194 (33.0%) patients died. The 1-year and 2-year survival rates were 87% versus 46% and 62% versus 21%, respectively, for patients with versus without antifibrotic therapy. The risk of death was 37% lower in patients with antifibrotic therapy (hazard ratio 0.63, 95% CI 0.45; 0.87; p=0.005). The results were robust (and remained statistically significant) on multivariable analysis. Overall decline of FVC and D LCO was slow and did not differ significantly between patients with or without antifibrotic therapy. CONCLUSIONS: Survival was significantly higher in IPF patients with antifibrotic therapy, but the course of lung function parameters was similar in patients with and without antifibrotic therapy. This suggests that in clinical practice, premature mortality of IPF patients eventually occurs despite stable measurements for FVC and D LCO.

Variability of forced vital capacity in progressive interstitial lung disease: a prospective observational study.

BACKGROUND: Fibrotic interstitial lung disease (ILD) is often associated with poor outcomes, but has few predictors of progression. Daily home spirometry has been proposed to provide important information about the clinical course of idiopathic pulmonary disease (IPF). However, experience is limited, and home spirometry is not a routine component of patient care in ILD. Using home spirometry, we aimed to investigate the predictive potential of daily measurements of forced vital capacity (FVC) in fibrotic ILD. METHODS: In this prospective observational study, patients with fibrotic ILD and clinical progression were provided with home spirometers for daily measurements over 6 months. Hospital based spirometry was performed after three and 6 months. Disease progression, defined as death, lung transplantation, acute exacerbation or FVC decline > 10% relative was assessed in the cohort. RESULTS: From May 2017 until August 2018, we included 47 patients (IPF n = 20; non-IPF n = 27). Sufficient daily measurements were performed by 85.1% of the study cohort. Among these 40 patients (IPF n = 17; non-IPF n = 23), who had a mean ± SD age of 60.7 ± 11.3 years and FVC 64.7 ± 21.7% predicted (2.4 ± 0.8 L), 12 patients experienced disease progression (death: n = 2; lung transplantation: n = 3; acute exacerbation: n = 1; FVC decline > 10%: n = 6). Within the first 28 days, a group of patients had high daily variability in FVC, with 60.0% having a variation ≥5%. Patients with disease progression had significantly higher FVC variability than those in the stable group (median variability 8.6% vs. 4.8%; p = 0.002). Cox regression identified FVC variability as independently associated with disease progression when controlling for multiple confounding variables (hazard ratio: 1.203; 95% CI:1.050-1.378; p = 0.0076). CONCLUSIONS: Daily home spirometry is feasible in IPF and non-IPF ILD and facilitates the identification of FVC variability, which was associated with disease progression.

The clinical course of idiopathic pulmonary fibrosis and its association to quality of life over time: longitudinal data from the INSIGHTS-IPF registry.

BACKGROUND: Quality of life (QoL) is profoundly impaired in patients with idiopathic pulmonary fibrosis (IPF). However, data is limited regarding the course of QoL. We therefore analysed longitudinal data from the German INSIGHTS-IPF registry. METHODS: Clinical status and QoL were assessed at enrollment and subsequently at 6- to 12-months intervals. A range of different QoL questionnaires including the St. George's Respiratory Questionnaire (SGRQ) were used. RESULTS: Data from 424 patients were included; 76.9% male; mean age 68.7 ± 9.1 years, mean FVC% predicted 75.9 ± 19.4, mean DLCO% predicted 36.1 ± 15.9. QoL worsened significantly during follow-up with higher total SGRQ scores (increased by 1.47 per year; 95% CI: 1.17 to 1.76; p < 0.001) and higher UCSD-SOBQ scores and lower EQ-5D VAS and WHO-5 scores. An absolute decline in FVC% predicted of > 10% was associated with a significant deterioration in SGRQ (increasing by 9.08 units; 95% CI: 2.48 to 15.67; p = 0.007), while patients with stable or improved FVC had no significantly change in SGRQ. Patients with a > 10% decrease of DLCO % predicted also had a significant increase in SGRQ (+ 7.79 units; 95% CI: 0.85 to 14.73; p = 0.028), while SQRQ was almost stable in patients with stable or improved DLCO. Patients who died had a significant greater increase in SGRQ total scores (mean 11.8 ± 18.6) at their last follow-up visit prior to death compared to survivors (mean 4.2 ± 18.9; HR = 1.03; 95% CI: 1.01 to 1.04; p < 0.001). All QoL scores across the follow-up period were significantly worse in hospitalised patients compared to non-hospitalised patients, with the worst scores reported in those hospitalised for acute exacerbations. CONCLUSIONS: QoL assessments in the INSIGHTS-IPF registry demonstrate a close relationship between QoL and clinically meaningful changes in lung function, comorbidities, disease duration and clinical course of IPF, including hospitalisation and mortality.

Increased Extracellular Vesicles Mediate WNT5A Signaling in Idiopathic Pulmonary Fibrosis.

Rationale: Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease characterized by lung epithelial cell injury, increased (myo)fibroblast activation, and extracellular matrix deposition. Extracellular vesicles (EVs) regulate intercellular communication by carrying a variety of signaling mediators, including WNT (wingless/integrated) proteins. The relevance of EVs in pulmonary fibrosis and their potential contribution to disease pathogenesis, however, remain unexplored.Objectives: To characterize EVs and study the role of EV-bound WNT signaling in IPF.Methods: We isolated EVs from BAL fluid (BALF) from experimental lung fibrosis as well as samples from IPF, non-IPF interstitial lung disease (ILD), non-ILD, and healthy volunteers from two independent cohorts. EVs were characterized by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. Primary human lung fibroblasts (phLFs) were used for EV isolation and analyzed by metabolic activity assays, cell counting, quantitative PCR, and Western blotting upon WNT gain- and loss-of-function studies.Measurements and Main Results: We found increased EVs, particularly exosomes, in BALF from experimental lung fibrosis as well as from patients with IPF. WNT5A was secreted on EVs in lung fibrosis and induced by transforming growth factor-ß in primary human lung fibroblasts. The phLF-derived EVs induced phLF proliferation, which was attenuated by WNT5A silencing and antibody-mediated inhibition and required intact EV structure. Similarly, EVs from IPF BALF induced phLF proliferation, which was mediated by WNT5A.Conclusions: Increased EVs function as carriers for signaling mediators, such as WNT5A, in IPF and thus contribute to disease pathogenesis. Characterization of EV secretion and composition may lead to novel approaches to diagnose and develop treatments for pulmonary fibrosis.

Cell-surface phenotyping identifies CD36 and CD97 as novel markers of fibroblast quiescence in lung fibrosis.

Fibroblasts play an important role in lung homeostasis and disease. In lung fibrosis, fibroblasts adopt a proliferative and migratory phenotype, with increased expression of α-smooth muscle actin (αSMA) and enhanced secretion of extracellular matrix components. Comprehensive profiling of fibroblast heterogeneity is limited because of a lack of specific cell-surface markers. We have previously profiled the surface proteome of primary human lung fibroblasts. Here, we sought to define and quantify a panel of cluster of differentiation (CD) markers in primary human lung fibroblasts and idiopathic pulmonary fibrosis (IPF) lung tissue, using immunofluorescence and FACS analysis. Fibroblast function was assessed by analysis of replicative senescence. We observed the presence of distinct fibroblast phenotypes in vivo, characterized by various combinations of Desmin, αSMA, CD36, or CD97 expression. Most markers demonstrated stable expression over passages in vitro, but significant changes were observed for CD36, CD54, CD82, CD106, and CD140a. Replicative senescence of fibroblasts was observed from passage 10 onward. CD36- and CD97-positive but αSMA-negative cells were present in remodeled areas of IPF lungs. Transforming growth factor (TGF)-ß treatment induced αSMA and collagen I expression but repressed CD36 and CD97 expression. We identified a panel of stable surface markers in human lung fibroblasts, applicable for positive-cell isolation directly from lung tissue. TGF-ß exposure represses CD36 and CD97 expression, despite increasing αSMA expression; we therefore identified complex surface protein changes during fibroblast-myofibroblast activation. Coexistence of quiescence and activated fibroblast subtypes in the IPF lung suggests dynamic remodeling of fibroblast activation upon subtle changes to growth factor exposure in local microenvironmental niches.

slan-defined subsets of CD16-positive monocytes: impact of granulomatous inflammation and M-CSF receptor mutation.

Human monocytes are subdivided into classical, intermediate, and nonclassical subsets, but there is no unequivocal strategy to dissect the latter 2 cell types. We show herein that the cell surface marker 6-sulfo LacNAc (slan) can define slan-positive CD14(+)CD16(++) nonclassical monocytes and slan-negative CD14(++)CD16(+) intermediate monocytes. Gene expression profiling confirms that slan-negative intermediate monocytes show highest expression levels of major histocompatibility complex class II genes, whereas a differential ubiquitin signature is a novel feature of the slan approach. In unsupervised hierarchical clustering, the slan-positive nonclassical monocytes cluster with monocytes and are clearly distinct from CD1c(+) dendritic cells. In clinical studies, we show a selective increase of the slan-negative intermediate monocytes to >100 cells per microliter in patients with sarcoidosis and a fivefold depletion of the slan-positive monocytes in patients with hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS), which is caused by macrophage colony-stimulating factor (M-CSF) receptor mutations. These data demonstrate that the slan-based definition of CD16-positive monocyte subsets is informative in molecular studies and in clinical settings.

Health related quality of life in patients with idiopathic pulmonary fibrosis in clinical practice: insights-IPF registry.

BACKGROUND: The INSIGHTS-IPF registry provides one of the largest data sets of clinical data and self-reported patient related outcomes including health related quality of life (QoL) on patients with idiopathic pulmonary fibrosis (IPF). We aimed to describe associations of various QoL instruments between each other and with patient characteristics at baseline. METHODS: Six hundred twenty-three IPF patients with available QoL data (St George's Respiratory Questionnaire SGRQ, UCSD Shortness-of-Breath Questionnaire SoB, EuroQol visual analogue scale and index EQ-5D, Well-being Index WHO-5) were analysed. Mean age was 69.6 ± 8.7 years, 77% were males, mean disease duration 2.0 ± 3.3 years, FVC pred was 67.5 ± 17.8%, DLCO pred 35.6 ± 17%. RESULTS: Mean points were SGRQ total 48.3, UCSD SoB 47.8, EQ-5D VAS 66.8, and WHO-5 13.9. These instruments had a high or very high correlation (exception WHO-5 to EQ-5D VAS with moderate correlation). On bivariate analysis, QoL by SGRQ total was statistically significantly associated with clinical symptoms (NYHA; p < 0.001), number of comorbidities (p < 0.05), hospitalisation rate (p < 0.01) and disease severity (as measured by GAP score, CPI, FVC and 6-min walk test; p < 0.05 each). Multivariate analyses showed a significant association between QoL (by SGRQ total) and IPF duration, FVC, age, NYHA class and indication for long-term oxygen treatment. CONCLUSIONS: Overall, IPF patients under real-life conditions have lower QoL compared to those in clinical studies. There is a meaningful relationship between QoL and various patient characteristics. TRIAL REGISTRATION: The INSIGHTS-IPF registry is registered at Clinicaltrials.gov ( NCT01695408 ).

A novel role of MMP-13 for murine DC function: its inhibition dampens T-cell activation.

Dendritic cells (DCs) have been shown to express matrix metalloproteinase 13 (MMP-13), but little is known about its specific function in DCs and its role in inflammatory conditions. In the present study, we describe a novel role of MMP-13 in regulating the immunostimulatory function of murine DCs through moderating MHC-I surface presentation, endocytosis and cytokine/chemokine secretion. MMP-13 expression was confirmed in bone marrow-derived DCs at both the mRNA and the protein level and, furthermore, at the activity level. Remarkably, LPS treatment strongly enhanced MMP-13 mRNA expression as well as MMP-13 activity, indicating an important role of MMP-13 in inflammatory processes. Functionally, MMP-13 inhibition did not influence the DC migratory capacity, while endocytosis of ovalbumin was significantly decreased. Inhibition of MMP-13 lowered the capability of murine DCs to activate CD8+ T cells, apparently through reducing MHC-I surface presentation. Decreased surface expression of CD11c on DCs, as well as changes in the DC cytokine/chemokine profile after MMP-13 inhibition, emphasizes the influence of MMP-13 on DC function. Moreover, T-cell-targeting cytokines such as IL-12, IL-23 and IL-6 were significantly reduced. Collectively, our data reveal a novel involvement of MMP-13 in regulating DC immunobiology through moderating MHC-I surface presentation, endocytosis and cytokine/chemokine secretion. Furthermore, the reduced MHC-I surface presentation by DCs resulted in a poor CD8+ T-cell response in vitro This novel finding indicates that MMP-13 might be a promising target for therapeutic intervention in inflammatory diseases.

Peripheral blood myeloid-derived suppressor cells reflect disease status in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative disease with irreversible lung function loss and poor survival. Myeloid-derived suppressor cells (MDSC) are associated with poor prognosis in cancer, facilitating immune evasion. The abundance and function of MDSC in IPF is currently unknown.Fluorescence-activated cell sorting was performed in 170 patients (IPF: n=69; non-IPF interstitial lung disease (ILD): n=56; chronic obstructive pulmonary disease (COPD): n=23; healthy controls: n=22) to quantify blood MDSC and lymphocyte subtypes. MDSC abundance was correlated with lung function, MDSC localisation was performed by immunofluorescence. Peripheral blood mononuclear cell (PBMC) mRNA levels were analysed by qRT-PCR.We detected increased MDSC in IPF and non-IPF ILD compared with controls (30.99±15.61% versus 18.96±8.17%, p≤0.01). Circulating MDSC inversely correlated with maximum vital capacity (r= -0.48, p≤0.0001) in IPF, but not in COPD or non-IPF ILD. MDSC suppressed autologous T-cells. The mRNA levels of co-stimulatory T-cell signals were significantly downregulated in IPF PBMC. Importantly, CD33+CD11b+ cells, suggestive of MDSC, were detected in fibrotic niches of IPF lungs.We identified increased MDSC in IPF and non-IPF ILD, suggesting that elevated MDSC may cause a blunted immune response. MDSC inversely correlate with lung function only in IPF, identifying them as potent biomarkers for disease progression. Controlling expansion and accumulation of MDSC, or blocking their T-cell suppression, represents a promising therapy in IPF.

Transcript profiling of CD16-positive monocytes reveals a unique molecular fingerprint.

CD16-positive (CD14(++) CD16(+) and CD14(+) CD16(++) ) monocytes have unique features with respect to phenotype and function. We have used transcriptional profiling for comparison of CD16-positive monocytes and classical monocytes. We show herein that 187 genes are greater than fivefold differentially expressed, including 90 genes relevant to immune response and inflammation. Hierarchical clustering of data for monocyte subsets and CD1c(+) myeloid blood dendritic cells (DCs) demonstrate that CD16-positive cells are more closely related to classical monocytes than to DCs. Reverse transcriptase polymerase chain reaction for ten genes with the strongest differential expression confirmed the pattern including a lower messenger RNA level for CD14, CD163, and versican in CD16-positive monocytes. The pattern was similar for CD16-positive monocytes at rest and after exercise mobilization from the marginal pool. By contrast, alveolar macrophages, small sputum macrophages, breast milk macrophages, and synovial macrophages all showed a different pattern. When monocyte-derived macrophages (MDMs) were generated from CD16-positive monocytes by culture with macrophage colony-stimulating factor in vitro, then the MDMs maintained properties of their progeny with lower expression of CD14, CD163, and versican compared with CD14(++) CD16(-) MDMs. Furthermore, CD16-positive MDMs showed a higher phagocytosis for opsonized Escherichia coli. The data demonstrate that CD16-positive monocytes form a distinct type of cell, which gives rise to a distinct macrophage phenotype.

Gender-specific differences in COPD symptoms and their impact for the diagnosis of cardiac comorbidities.

BACKGROUND: In chronic obstructive pulmonary disease (COPD), gender-specific differences in the prevalence of symptoms and comorbidity are known. RESEARCH QUESTION: We studied whether the relationship between these characteristics depended on gender and carried diagnostic information regarding cardiac comorbidities. STUDY DESIGN AND METHODS: The analysis was based on 2046 patients (GOLD grades 1-4, 795 women; 38.8%) from the COSYCONET COPD cohort. Assessments comprised the determination of clinical history, comorbidities, lung function, COPD Assessment Test (CAT) and modified Medical Research Council dyspnea scale (mMRC). Using multivariate regression analyses, gender-specific differences in the relationship between symptoms, single CAT items, comorbidities and functional alterations were determined. To reveal the relationship to cardiac disease (myocardial infarction, or heart failure, or coronary artery disease) logistic regression analysis was performed separately in men and women. RESULTS: Most functional parameters and comorbidities, as well as CAT items 1 (cough), 2 (phlegm) and 5 (activities), differed significantly (p < 0.05) between men and women. Beyond this, the relationship between functional parameters and comorbidities versus symptoms showed gender-specific differences, especially for single CAT items. In men, item 8 (energy), mMRC, smoking status, BMI, age and spirometric lung function was related to cardiac disease, while in women primarily age was predictive. INTERPRETATION: Gender-specific differences in COPD not only comprised differences in symptoms, comorbidities and functional alterations, but also differences in their mutual relationships. This was reflected in different determinants linked to cardiac disease, thereby indicating that simple diagnostic information might be used differently in men and women. CLINICAL TRIAL REGISTRATION: The cohort study is registered on ClinicalTrials.gov with identifier NCT01245933 and on GermanCTR.de with identifier DRKS00000284, date of registration November 23, 2010. Further information can be obtained on the website http://www.asconet.net .

Monocyte signature as a predictor of chronic lung disease in the preterm infant.

Introduction: Inflammation is a key driver of morbidity in the vulnerable preterm infant exposed to pre- and postnatal hazards and significantly contributes to chronic lung disease, i.e. bronchopulmonary dysplasia (BPD). However, the early changes in innate immunity associated with BPD development are incompletely understood. Methods: In very immature preterm infants below 32 weeks gestational age (GA; n=30 infants), monocyte subtypes were identified by Flow Cytometry at birth and throughout the postnatal course including intracellular TNF expression upon LPS stimulation. Complementing these measurements, cytokine end growth factor expression profiles (Luminex® xMAP®; n=110 infants) as well as gene expression profiles (CodeLinkTM Human I Bioarray; n=22) were characterized at birth. Results: The abundance of monocyte subtypes differed between preterm and term neonates at birth. Specifically, CD14++CD16+ (intermediate) monocytes demonstrated a dependency on PMA and elevated levels of nonclassical (CD14+CD16++) monocytes characterized preterm infants with developing BPD. Postnatally, lung injury was associated with an increase in intermediate monocytes, while high levels of nonclassical monocytes persisted. Both subtypes were revealed as the main source of intracellular TNF-α expression in the preterm infant. We identified a cytokine and growth factor expression profile in cord blood specimen of preterm infants with developing BPD that corresponded to the disease-dependent regulation of monocyte abundances. Multivariate modeling of protein profiles revealed FGF2, sIL-2 Rα, MCP-1, MIP1a, and TNF-α as predictors of BPD when considering GA. Transcriptome analysis demonstrated genes predicting BPD to be overrepresented in inflammatory pathways with increased disease severity characterized by the regulation of immune and defense response pathways and upstream regulator analysis confirmed TNF-α, interleukin (IL) -6, and interferon α as the highest activated cytokines in more severe disease. Whereas all BPD cases showed downstream activation of chemotaxis and activation of inflammatory response pathways, more severe cases were characterized by an additional activation of reactive oxygen species (ROS) synthesis. Discussion: In the present study, we identified the early postnatal presence of nonclassical (CD14+CD16++) and intermediate (CD14++CD16+) monocytes as a critical characteristic of BPD development including a specific response pattern of monocyte subtypes to lung injury. Pathophysiological insight was provided by the protein and transcriptome signature identified at birth, centered around monocyte and corresponding granulocyte activation and highlighting TNFα as a critical regulator in infants with developing BPD. The disease severity-dependent expression patterns could inform future diagnostic and treatment strategies targeting the monocytic cell and its progeny.

Corrigendum: Monocyte signature as a predictor of chronic lung disease in the preterm infant.

[This corrects the article DOI: 10.3389/fimmu.2023.1112608.].

Mass spectrometry-based autoimmune profiling reveals predictive autoantigens in idiopathic pulmonary fibrosis.

Autoimmunity plays a role in certain types of lung fibrosis, notably connective tissue disease-associated interstitial lung disease (CTD-ILD). In idiopathic pulmonary fibrosis (IPF), an incurable and fatal lung disease, diagnosis typically requires clinical exclusion of autoimmunity. However, autoantibodies of unknown significance have been detected in IPF patients. We conducted computational analysis of B cell transcriptomes in published transcriptomics datasets and developed a proteomic Differential Antigen Capture (DAC) assay that captures plasma antibodies followed by affinity purification of lung proteins coupled to mass spectrometry. We analyzed antibody capture in two independent cohorts of IPF and CTL-ILD patients over two disease progression time points. Our findings revealed significant upregulation of specific immunoglobulins with V-segment bias in IPF across multiple cohorts. We identified a predictive autoimmune signature linked to reduced transplant-free survival in IPF, persisting over time. Notably, autoantibodies against thrombospondin-1 were associated with decreased survival, suggesting their potential as predictive biomarkers.

Proteomics reveals antiviral host response and NETosis during acute COVID-19 in high-risk patients.

SARS-CoV-2 remains an acute threat to human health, endangering hospital capacities worldwide. Previous studies have aimed at informing pathophysiologic understanding and identification of disease indicators for risk assessment, monitoring, and therapeutic guidance. While findings start to emerge in the general population, observations in high-risk patients with complex pre-existing conditions are limited. We addressed the gap of existing knowledge with regard to a differentiated understanding of disease dynamics in SARS-CoV-2 infection while specifically considering disease stage and severity. We biomedically characterized quantitative proteomics in a hospitalized cohort of COVID-19 patients with mild to severe symptoms suffering from different (co)-morbidities in comparison to both healthy individuals and patients with non-COVID related inflammation. Deep clinical phenotyping enabled the identification of individual disease trajectories in COVID-19 patients. By the use of the individualized disease phase assignment, proteome analysis revealed a severity dependent general type-2-centered host response side-by-side with a disease specific antiviral immune reaction in early disease. The identification of phenomena such as neutrophil extracellular trap (NET) formation and a pro-coagulatory response characterizing severe disease was successfully validated in a second cohort. Together with the regulation of proteins related to SARS-CoV-2-specific symptoms identified by proteome screening, we not only confirmed results from previous studies but provide novel information for biomarker and therapy development.

The EvA study: aims and strategy.

The EvA study is a European Union-funded project under the Seventh Framework Programme (FP7), which aims at defining new markers for chronic obstructive pulmonary disease (COPD) and its subtypes. The acronym is derived from emphysema versus airway disease, indicating that the project targets these two main phenotypes of the disease. The EvA study is based on the concept that emphysema and airway disease are governed by different pathophysiological processes, are driven by different genes and have differential gene expression in the lung. To define these genes, patients and non-COPD controls are recruited for clinical examination, lung function analysis and computed tomography (CT) of the lung. CT scans are used to define the phenotypes based on lung density and airway wall thickness. This is followed by bronchoscopy in order to obtain samples from the airways and the alveoli. These tissue samples, along with blood samples, are then subjected to genome-wide expression and association analysis and markers linked to the phenotypes are identified. The population of the EvA study is different from other COPD study populations, since patients with current oral glucocorticoids, antibiotics and exacerbations or current smokers are excluded, such that the signals detected in the molecular analysis are due to the distinct inflammatory process of emphysema and airway disease in COPD.

Comparison of gene expression profiles between human and mouse monocyte subsets.

Blood of both humans and mice contains 2 main monocyte subsets. Here, we investigated the extent of their similarity using a microarray approach. Approximately 270 genes in humans and 550 genes in mice were differentially expressed between subsets by 2-fold or more. More than 130 of these gene expression differences were conserved between mouse and human monocyte subsets. We confirmed numerous of these differences at the cell surface protein level. Despite overall conservation, some molecules were conversely expressed between the 2 species' subsets, including CD36, CD9, and TREM-1. Other differences included a prominent peroxisome proliferator-activated receptor gamma (PPARgamma) signature in mouse monocytes, which is absent in humans, and strikingly opposed patterns of receptors involved in uptake of apoptotic cells and other phagocytic cargo between human and mouse monocyte subsets. Thus, whereas human and mouse monocyte subsets are far more broadly conserved than currently recognized, important differences between the species deserve consideration when models of human disease are studied in mice.