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Importance: Particulate matter 2.5 μm or less in diameter (PM2.5) is associated with adverse outcomes for patients with idiopathic pulmonary fibrosis, but its association with other fibrotic interstitial lung diseases (fILDs) and the association of PM2.5 composition with adverse outcomes remain unclear., Objective: To investigate the association of PM2.5 exposure with mortality and lung function among patients with fILD., Design, Setting, and Participants: In this multicenter, international, prospective cohort study, patients were enrolled in the Simmons Center for Interstitial Lung Disease Registry at the University of Pittsburgh in Pittsburgh, Pennsylvania; 42 sites of the Pulmonary Fibrosis Foundation Registry; and 8 sites of the Canadian Registry for Pulmonary Fibrosis. A total of 6683 patients with fILD were included (Simmons, 1424; Pulmonary Fibrosis Foundation, 1870; and Canadian Registry for Pulmonary Fibrosis, 3389). Data were analyzed from June 1, 2021, to August 2, 2022., Exposures: Exposure to PM2.5 and its constituents was estimated with hybrid models, combining satellite-derived aerosol optical depth with chemical transport models and ground-based PM2.5 measurements., Main Outcomes and Measures: Multivariable linear regression was used to test associations of exposures 5 years before enrollment with baseline forced vital capacity and diffusion capacity for carbon monoxide. Multivariable Cox models were used to test associations of exposure in the 5 years before censoring with mortality, and linear mixed models were used to test associations of exposure with a decrease in lung function. Multiconstituent analyses were performed with quantile-based g-computation. Cohort effect estimates were meta-analyzed. Models were adjusted for age, sex, smoking history, race, a socioeconomic variable, and site (only for Pulmonary Fibrosis Foundation and Canadian Registry for Pulmonary Fibrosis cohorts)., Results: Median follow-up across the 3 cohorts was 2.9 years (IQR, 1.5-4.5 years), with death for 28% of patients and lung transplant for 10% of patients. Of the 6683 patients in the cohort, 3653 were men (55%), 205 were Black (3.1%), and 5609 were White (84.0%). Median (IQR) age at enrollment across all cohorts was 66 (58-73) years. A PM2.5 exposure of 8 μg/m3 or more was associated with a hazard ratio for mortality of 4.40 (95% CI, 3.51-5.51) in the Simmons cohort, 1.71 (95% CI, 1.32-2.21) in the Pulmonary Fibrosis Foundation cohort, and 1.45 (95% CI, 1.18-1.79) in the Canadian Registry for Pulmonary Fibrosis cohort. Increasing exposure to sulfate, nitrate, and ammonium PM2.5 constituents was associated with increased mortality across all cohorts, and multiconstituent models demonstrated that these constituents tended to be associated with the most adverse outcomes with regard to mortality and baseline lung function. Meta-analyses revealed consistent associations of exposure to sulfate and ammonium with mortality and with the rate of decrease in forced vital capacity and diffusion capacity of carbon monoxide and an association of increasing levels of PM2.5 multiconstituent mixture with all outcomes., Conclusions and Relevance: This cohort study found that exposure to PM2.5 was associated with baseline severity, disease progression, and mortality among patients with fILD and that sulfate, ammonium, and nitrate constituents were associated with the most harm, highlighting the need for reductions in human-derived sources of pollution.

Purpose of Review: Pulmonary fibrosis is an incurable lung disease that leads to significant morbidity. In many patients, pulmonary fibrosis is progressive causing debilitating dyspnea that impairs patients' ability to perform everyday tasks and maintain independence. Informal caregivers provide invaluable support for patients with pulmonary fibrosis; however, support for the caregiver is inadequate. The purpose of this scoping review is to identify unmet needs for caregivers of pulmonary fibrosis patients., Recent Findings: During the past 18 months, there has been an increase in studies about the impact of pulmonary fibrosis on the caregiver or carer of the patient with pulmonary fibrosis. These carers experience caregiver burden which includes negative psychological and physical effects on caregiver health because of the challenge in caring for someone with pulmonary fibrosis. Caregivers describe the need for help navigating the healthcare system. This includes supportive and informational needs, lack of access to comprehensive patient-centred care, geographically accessible specialty centres and psychological support for both patient and caregiver., Summary: Caregivers of pulmonary fibrosis patients have numerous unmet care needs that include education about the disease, symptom management, financial assistance, access to specialty centres, advanced care planning and psychological support. This resulting caregiver burden can be alleviated with comprehensive support tailored throughout the disease course., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Although the etiology of idiopathic pulmonary fibrosis (IPF) remains perplexing, adaptive immune activation is evident among many afflicted patients. Repeated cycles of antigen-induced proliferation cause T-cells to lose surface expression of CD28, and we hypothesized this process might also occur in IPF., Methodology/principal Findings: Peripheral blood CD4 T-cells from 89 IPF patients were analyzed by flow cytometry and cytokine multiplex assays, and correlated with clinical events. In comparison to autologous CD4(+)CD28(+)cells, the unusual CD4(+)CD28(null) lymphocytes seen in many IPF patients had discordant expressions of activation markers, more frequently produced cytotoxic mediators perforin (2.4+/-0.8% vs. 60.0+/-7.4%, p<0.0001) and granzyme B (4.5+/-2.8% vs.74.9+/-6.5%, p<0.0001), produced greater amounts of many pro-inflammatory cytokines, and less frequently expressed the regulatory T-cell marker FoxP3 (12.9+/-1.1% vs. 3.3+/-0.6% p<0.0001). Infiltration of CD4(+)CD28(null) T-cells in IPF lungs was confirmed by confocal microscopy. Interval changes of CD28 expression among subjects who had replicate studies were correlated with conterminous changes of their forced vital capacities (r(s) = 0.49, p = 0.012). Most importantly, one-year freedom from major adverse clinical events (either death or lung transplantation) was 56+/-6% among 78 IPF patients with CD4(+)CD28(+)/CD4(total)>or=82%, compared to 9+/-9% among those with more extensive CD28 down-regulation (CD4(+)CD28(+)/CD4(total)<82%) (p = 0.0004). The odds ratio for major adverse events among those with the most extensive CD28 down-regulation was 13.0, with 95% confidence intervals 1.6-111.1., Conclusions/significance: Marked down-regulation of CD28 on circulating CD4 T-cells, a result of repeated antigen-driven proliferations, is associated with poor outcomes in IPF patients. The CD4(+)CD28(null) cells of these patients have potentially enhanced pathogenic characteristics, including increased productions of cytotoxic mediators and pro-inflammatory cytokines. These findings show proliferative T-cell responses to antigen(s) resulting in CD28 down-regulation are associated with progression and manifestations of IPF, and suggest assays of circulating CD4 T-cells may identify patients at greatest risk for clinical deterioration.

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic lung disease associated with substantial morbidity and mortality. The objective of this study was to determine whether there is a peripheral blood protein signature in IPF and whether components of this signature may serve as biomarkers for disease presence and progression., Methods and Findings: We analyzed the concentrations of 49 proteins in the plasma of 74 patients with IPF and in the plasma of 53 control individuals. We identified a combinatorial signature of five proteins-MMP7, MMP1, MMP8, IGFBP1, and TNFRSF1A-that was sufficient to distinguish patients from controls with a sensitivity of 98.6% (95% confidence interval [CI] 92.7%-100%) and specificity of 98.1% (95% CI 89.9%-100%). Increases in MMP1 and MMP7 were also observed in lung tissue and bronchoalveolar lavage fluid obtained from IPF patients. MMP7 and MMP1 plasma concentrations were not increased in patients with chronic obstructive pulmonary disease or sarcoidosis and distinguished IPF compared to subacute/chronic hypersensitivity pneumonitis, a disease that may mimic IPF, with a sensitivity of 96.3% (95% CI 81.0%-100%) and specificity of 87.2% (95% CI 72.6%-95.7%). We verified our results in an independent validation cohort composed of patients with IPF, familial pulmonary fibrosis, subclinical interstitial lung disease (ILD), as well as with control individuals. MMP7 and MMP1 concentrations were significantly higher in IPF patients compared to controls in this cohort. Furthermore, MMP7 concentrations were elevated in patients with subclinical ILD and negatively correlated with percent predicted forced vital capacity (FVC%) and percent predicted carbon monoxide diffusing capacity (DLCO%)., Conclusions: Our experiments provide the first evidence for a peripheral blood protein signature in IPF to our knowledge. The two main components of this signature, MMP7 and MMP1, are overexpressed in the lung microenvironment and distinguish IPF from other chronic lung diseases. Additionally, increased MMP7 concentration may be indicative of asymptomatic ILD and reflect disease progression.