Therapy-Induced Evolution of Human Lung Cancer Revealed by Single-Cell RNA Sequencing.

Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNA-seq) of metastatic lung cancer was performed using 49 clinical biopsies obtained from 30 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNA-seq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell-state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap-junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by scRNA-seq were biomarkers of clinical outcomes in independent cohorts. This study highlights how therapy-induced adaptation of the multi-cellular ecosystem of metastatic cancer shapes clinical outcomes.

Integrated Genomic and Clinicopathologic Approach Distinguishes Pancreatic Grade 3 Neuroendocrine Tumor From Neuroendocrine Carcinoma and Identifies a Subset With Molecular Overlap.

Distinguishing grade 3 pancreatic neuroendocrine tumor (G3 PanNET) from neuroendocrine carcinoma (PanNEC) is a known diagnostic challenge, and accurate classification is critical because clinical behavior and therapies differ. Although current recommendations suggest that immunohistochemistry for p53, Rb, ATRX, and DAXX can distinguish most cases, some cases remain difficult to classify using this approach. In this study, we reviewed 47 high-grade neoplasms originally diagnosed as pancreatic neuroendocrine neoplasms. In addition to the currently recommended stains, we performed capture-based sequencing of approximately 500 cancer genes and immunohistochemistry for p16 and trypsin or chymotrypsin. Using an integrated molecular and clinicopathologic approach, 42 (89%) of 47 cases had a clear final diagnosis of either G3 PanNET (n = 17), PanNEC (n = 17), or mixed acinar-NEC (n = 8). The 17 G3 PanNETs demonstrated frequent alterations in MEN1 (71%), DAXX (47%), ATRX (24%), TSC2 (35%), SETD2 (42%), and CDKN2A (41%). Contrary to prior reports, TP53 alterations were also common in G3 PanNETs (35%) but were always mutually exclusive with CDKN2A alterations in this group. The 17 PanNECs demonstrated frequent alterations in TP53 (88%), cell cycle genes RB1 (47%), CCNE1/CCND1 (12%), CDKN2A (29%), and in KRAS (53%) and SMAD4 (41%); TP53 was coaltered with a cell cycle gene in 76% of PanNECs. Diffuse strong p16 staining was observed in 69% of PanNECs in contrast to 0% of G3 PanNETs. The 8 acinar-NECs had recurrent alterations in ATM (25%), APC (25%), and STK11 (25%). Five cases remained difficult to classify, 3 of which exhibited overlapping molecular features with alterations in MEN1 with or without ATRX, and RB1 with or without TP53, making it unclear whether to classify as PanNET or PanNEC. Our data demonstrate that molecular profiling and immunohistochemistry for p16 greatly improve the diagnostic accuracy of high-grade pancreatic neuroendocrine neoplasms and identify a subset of rare cases with overlapping features of both PanNET and PanNEC.

Aerosolized vitamin E acetate causes oxidative injury in mice and in alveolar macrophages.

Although vitamin E acetate (VEA) is suspected to play a causal role in the development of electronic-cigarette, or vaping, product use-associated lung injury (EVALI), the underlying biological mechanisms of pulmonary injury are yet to be determined. In addition, no study has replicated the systemic inflammation observed in humans in a murine EVALI model, nor investigated potential additive toxicity of viral infection in the setting of exposure to vaping products. To identify the mechanisms driving VEA-related lung injury and test the hypothesis that viral infection causes additive lung injury in the presence of aerosolized VEA, we exposed mice to aerosolized VEA for extended times, followed by influenza infection in some experiments. We used mass spectrometry to evaluate the composition of aerosolized VEA condensate and the VEA deposition in murine or human alveolar macrophages. Extended vaping for 28 days versus 15 days did not worsen lung injury but caused systemic inflammation in the murine EVALI model. Vaping plus influenza increased lung water compared with virus alone. Murine alveolar macrophages exposed to vaped VEA hydrolyzed the VEA to vitamin E with evidence of oxidative stress in the alveolar space and systemic circulation. Aerosolized VEA also induced cell death and chemokine release and reduced efferocytotic function in human alveolar macrophages in vitro. These findings provide new insights into the biological mechanisms of VEA toxicity.

The hidden history of hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is a relatively new construct, first reported in the early 20th century, despite major aetiological factors (farming, bird husbandry) having been part of human activities for millennia. Initial confirmed HP reports included exposure to farming and forestry (1932) and bird exposure (1965), much more recently than is often assumed. Later changes in occupational and living practices have led to HP associated with isocyanates, machine coolants, indoor mould, hot tubs and other exposures. Evolution of our pathological understanding of interstitial lung disease in general, wider computed tomography utilisation and advances in immunology and genomics have shaped our modern conceptualisation of HP. Examining historical accounts of HP and its causative factors not only considers when the first cases were recognised, but also explores why the disease emerged at specific times and places, and may provide further insights relevant to the mechanisms underlying HP and disease prevention.

Genetic and immunohistochemical profiling of small cell and large cell neuroendocrine carcinomas of the breast.

Neuroendocrine carcinomas (NEC) of the breast are exceedingly rare tumors, which are classified in the WHO system as small cell (SCNEC) and large cell (LCNEC) carcinoma based on indistinguishable features from their lung counterparts. In contrast to lung and enteropancreatic NEC, the genomics of breast NEC have not been well-characterized. In this study, we examined the clinicopathologic, immunohistochemical, and genetic features of 13 breast NEC (7 SCNEC, 4 LCNEC, 2 NEC with ambiguous small versus large cell morphology [ANEC]). Co-alterations of TP53 and RB1 were identified in 86% (6/7) SCNEC, 100% (2/2) ANEC, and 50% (2/4) LCNEC. The one SCNEC without TP53/RB1 alteration had other p53 pathway aberrations (MDM2 and MDM4 amplification) and was immunohistochemically RB negative. PIK3CA/PTEN pathway alterations and ZNF703 amplifications were each identified in 46% (6/13) NEC. Two tumors (1 SCNEC, 1 LCNEC) were CDH1 mutated. By immunohistochemistry, 100% SCNEC (6/6) and ANEC (2/2) and 50% (2/4) LCNEC (83% NEC) showed RB loss, compared to 0% (0/8) grade 3 neuroendocrine tumors (NET) (p < 0.001) and 38% (36/95) grade 3 invasive ductal carcinomas of no special type (IDC-NST) (p = 0.004). NEC were also more often p53 aberrant (60% vs 0%, p = 0.013), ER negative (69% vs 0%, p = 0.005), and GATA3 negative (67% vs 0%, p = 0.013) than grade 3 NET. Two mixed NEC had IDC-NST components, and 69% (9/13) of tumors were associated with carcinoma in situ (6 neuroendocrine DCIS, 2 non-neuroendocrine DCIS, 1 non-neuroendocrine LCIS). NEC and IDC-NST components of mixed tumors were clonally related and immunophenotypically distinct, lacking ER and GATA3 expression in NEC relative to IDC-NST, with RB loss only in NEC of one ANEC. The findings provide insight into the pathogenesis of breast NEC, underscore their classification as a distinct tumor type, and highlight genetic similarities to extramammary NEC, including highly prevalent p53/RB pathway aberrations in SCNEC.

A Defect in Thymic Tolerance Causes T Cell-Mediated Autoimmunity in a Murine Model of COPA Syndrome.

COPA syndrome is a recently described Mendelian autoimmune disorder caused by missense mutations in the coatomer protein complex subunit α (COPA) gene. Patients with COPA syndrome develop arthritis and lung disease that presents as pulmonary hemorrhage or interstitial lung disease (ILD). Immunosuppressive medications can stabilize the disease, but many patients develop progressive pulmonary fibrosis, which requires life-saving measures, such as lung transplantation. Because very little is understood about the pathogenesis of COPA syndrome, it has been difficult to devise effective treatments for patients. To date, it remains unknown which cell types are critical for mediating the disease as well as the mechanisms that lead to autoimmunity. To explore these issues, we generated a CopaE241K/+ germline knock-in mouse bearing one of the same Copa missense mutations in patients. Mutant mice spontaneously developed ILD that mirrors lung pathology in patients, as well as elevations of activated cytokine-secreting T cells. In this study, we show that mutant Copa in epithelial cells of the thymus impairs the thymic selection of T cells and results in both an increase in autoreactive T cells and decrease in regulatory T cells in peripheral tissues. We demonstrate that T cells from CopaE241K/+ mice are pathogenic and cause ILD through adoptive transfer experiments. In conclusion, to our knowledge, we establish a new mouse model of COPA syndrome to identify a previously unknown function for Copa in thymocyte selection and demonstrate that a defect in central tolerance is a putative mechanism by which COPA mutations lead to autoimmunity in patients.

Chronic lung allograft dysfunction small airways reveal a lymphocytic inflammation gene signature.

Chronic lung allograft dysfunction (CLAD) is the major barrier to long-term survival following lung transplantation, and new mechanistic biomarkers are needed. Lymphocytic bronchitis (LB) precedes CLAD and has a defined molecular signature. We hypothesized that this LB molecular signature would be associated with CLAD in small airway brushings independent of infection. We quantified RNA expression from small airway brushings and transbronchial biopsies, using RNAseq and digital RNA counting, respectively, for 22 CLAD cases and 27 matched controls. LB metagene scores were compared across CLAD strata by Wilcoxon rank sum test. We performed unbiased host transcriptome pathway and microbial metagenome analysis in airway brushes and compared machine-learning classifiers between the two tissue types. This LB metagene score was increased in CLAD airway brushes (p = .002) and improved prediction of graft failure (p = .02). Gene expression classifiers based on airway brushes outperformed those using transbronchial biopsies. While infection was associated with decreased microbial alpha-diversity (p ≤ .04), neither infection nor alpha-diversity was associated with LB gene expression. In summary, CLAD was associated with small airway gene expression changes not apparent in transbronchial biopsies in this cohort. Molecular analysis of airway brushings for diagnosing CLAD merits further examination in multicenter cohorts.

Resectability, Recurrence, and Risk Stratification of Giant Solitary Fibrous Tumors in the Thoracic Cavity.

BACKGROUND: Solitary fibrous tumors (SFTs) are rare mesenchymal tumors most commonly arising from the pleura in the thoracic cavity. The impact of tumor size on risk of recurrence in thoracic SFTs is not well understood. METHODS: A single institution review was performed on all resected thoracic SFTs (1992-2019) with giant SFT defined as ≥ 15 cm. Clinical information, pathologic characteristics, and long-term survival data were collected, and predictors of recurrence and survival were evaluated with regression and Kaplan-Meier analysis. RESULTS: There were 38 thoracic SFTs resected from patients, with the majority of tumors (n = 23, 60.5%) originating from visceral pleura. There were nine (23.7%) giant SFTs with a mean size 20.4 cm (range 17-30 cm). Mean follow-up time was 81.0 months (range 1-261 months), during which 4 of 38 (10.5%) patients experienced a recurrence within the thorax (range 51-178 months). The presence of tumor necrosis (p = 0.021) and ≥ 4 mitoses per high-powered field (p = 0.010) were associated with SFT recurrence on univariate regression. Overall 5-year, 10-year, and 20-year survival was 78.2%, 72.6%, and 42.4%, respectively, and SFT-related mortality occurred in three patients at 83, 180, and 208 months postoperatively. There were no recurrences or SFT-related mortality among patients with giant SFT. CONCLUSION: This study represents one of the largest contemporary single institution reviews of long-term outcomes of giant thoracic SFT. Our data suggest that size is not a risk factor for recurrence in thoracic SFTs and long-term survival is excellent for giant SFTs.

Molecular markers of telomere dysfunction and senescence are common findings in the usual interstitial pneumonia pattern of lung fibrosis.

AIMS: Idiopathic pulmonary fibrosis (IPF) is a genetically mediated, age-associated, progressive form of pulmonary fibrosis characterised pathologically by a usual interstitial pneumonia (UIP) pattern of fibrosis. The UIP pattern is also found in pulmonary fibrosis attributable to clinical diagnoses other than IPF (non-IPF UIP), whose clinical course is similarly poor, suggesting common molecular drivers. This study investigates whether IPF and non-IPF UIP lungs similarly express markers of telomere dysfunction and senescence. METHODS AND RESULTS: To test whether patients with IPF and non-IPF UIP share molecular drivers, lung tissues from 169 IPF patients and 57 non-IPF UIP patients were histopathologically and molecularly compared. Histopathological changes in both IPF and non-IPF UIP patients included temporal heterogeneity, microscopic honeycombing, fibroblast foci, and dense collagen fibrosis. Non-IPF UIP lungs were more likely to have lymphocytic infiltration, non-caseating granulomas, airway-centred inflammation, or small airways disease. Telomeres were shorter in alveolar type II (AECII) cells of both IPF and non-IPF UIP lungs than in those of age-similar, unused donor, controls. Levels of molecular markers of senescence (p16 and p21) were elevated in lysates of IPF and non-IPF UIP lungs. Immunostaining localised expression of these proteins to AECII cells. The mucin 5B (MUC5B) gene promoter variant minor allele frequency was similar between IPF and non-IPF UIP patients, and MUC5B expression was similar in IPF and non-IPF UIP lungs. CONCLUSIONS: Molecular markers of telomere dysfunction and senescence are pathologically expressed in both IPF and non-IPF UIP lungs. These findings suggest that common molecular drivers may contribute to the pathogenesis of UIP-associated pulmonary fibrosis, regardless of the clinical diagnosis.

Dose-Dependent Pulmonary Toxicity of Aerosolized Vitamin E Acetate.

Electronic-cigarette, or vaping, product use-associated lung injury (EVALI) is a syndrome of acute respiratory failure characterized by monocytic and neutrophilic alveolar inflammation. Epidemiological and clinical evidence suggests a role of vitamin E acetate (VEA) in the development of EVALI, yet it remains unclear whether VEA has direct pulmonary toxicity. To test the hypotheses that aerosolized VEA causes lung injury in mice and directly injures human alveolar epithelial cells, we exposed adult mice and primary human alveolar epithelial type II (AT II) cells to an aerosol of VEA generated by a device designed for vaping oils. Outcome measures in mice included lung edema, BAL analysis, histology, and inflammatory cytokines; in vitro outcomes included cell death, cytokine release, cellular uptake of VEA, and gene-expression analysis. Comparison exposures in both models included the popular nicotine-containing JUUL aerosol. We discovered that VEA caused dose-dependent increases in lung water and BAL protein compared with control and JUUL-exposed mice in association with increased BAL neutrophils, oil-laden macrophages, multinucleated giant cells, and inflammatory cytokines. VEA aerosol was also toxic to AT II cells, causing increased cell death and the release of monocyte and neutrophil chemokines. VEA was directly absorbed by AT II cells, resulting in the differential gene expression of several inflammatory biological pathways. Given the epidemiological and clinical characteristics of the EVALI outbreak, these results suggest that VEA plays an important causal role.

Airway Epithelial Telomere Dysfunction Drives Remodeling Similar to Chronic Lung Allograft Dysfunction.

Telomere dysfunction is associated with multiple fibrotic lung processes, including chronic lung allograft dysfunction (CLAD)-the major limitation to long-term survival following lung transplantation. Although shorter donor telomere lengths are associated with an increased risk of CLAD, it is unknown whether short telomeres are a cause or consequence of CLAD pathology. Our objective was to test whether telomere dysfunction contributes to the pathologic changes observed in CLAD. Histopathologic and molecular analysis of human CLAD lungs demonstrated shortened telomeres in lung epithelial cells quantified by teloFISH, increased numbers of surfactant protein C immunoreactive type II alveolar epithelial cells, and increased expression of senescence markers (ß-galactosidase, p16, p53, and p21) in lung epithelial cells. TRF1F/F (telomere repeat binding factor 1 flox/flox) mice were crossed with tamoxifen-inducible SCGB1a1-cre mice to generate SCGB1a1-creTRF1F/F mice. Following 9 months of tamoxifen-induced deletion of TRF1 in club cells, mice developed mixed obstructive and restrictive lung physiology, small airway obliteration on microcomputed tomography, a fourfold decrease in telomere length in airway epithelial cells, collagen deposition around bronchioles and adjacent lung parenchyma, increased type II aveolar epithelial cell numbers, expression of senescence-associated ß-galactosidase in epithelial cells, and decreased SCGB1a1 expression in airway epithelial cells. These findings demonstrate that telomere dysfunction isolated to airway epithelial cells leads to airway-centric lung remodeling and fibrosis similar to that observed in patients with CLAD and suggest that lung epithelial cell telomere dysfunction may be a molecular driver of CLAD.

Rare Protein-Altering Telomere-related Gene Variants in Patients with Chronic Hypersensitivity Pneumonitis.

Rationale: Rare genetic variants in telomere-related genes have been identified in familial, idiopathic, and rheumatoid arthritis-associated pulmonary fibrosis. Short peripheral blood leukocyte (PBL) telomere length predicts poor outcomes in chronic hypersensitivity pneumonitis (CHP).Objectives: Determine the prevalence and clinical relevance of rare protein-altering variants in telomere-related genes in patients with CHP.Methods: Next-generation sequences from two CHP cohorts were analyzed to identify variants in TERT (telomerase reverse transcriptase), TERC (telomerase RNA component), DKC1 (dyskerin pseudouridine synthase 1), RTEL1 (regulator of telomere elongation helicase 1), PARN (poly[A]-specific RNase), and TINF2 (TERF1-interacting nuclear factor 2). To qualify, variants were required to have a minor allele frequency less than 0.005 and be predicted to be damaging to protein function. Variant status (binary variable) was used in statistical association tests, including Cox proportional hazard models for transplant-free survival. PBL telomere length was measured using quantitative PCR.Measurements and Main Results: Qualifying variants were identified in 16 of 144 patients (11.1%; 95% confidence interval [CI], 6.5-17.4) in the discovery cohort and 17 of 209 patients (8.1%; 95% CI, 4.8-12.7) in the replication cohort. Age- and ancestry-adjusted PBL telomere length was significantly shorter in the presence of a variant in both cohorts (discovery: -561 bp; 95% CI, -933 to -190; P = 0.003; replication: -612 bp; 95% CI, -870 to -354; P = 5.30 × 10-6). Variant status was significantly associated with transplant-free survival in both cohorts (discovery: age-, sex-, and ancestry-adjusted hazard ratio, 3.73; 95% CI, 1.92-7.28; P = 0.0001; replication: hazard ratio, 2.72; 95% CI, 1.26-5.88; P = 0.011).Conclusions: A substantial proportion of patients diagnosed with CHP have rare, protein-altering variants in telomere-related genes, which are associated with short peripheral blood telomere length and significantly reduced transplant-free survival.

The Economic Implications of COVID-19 in the United States.

The novel coronavirus disease 2019 (COVID-19) first reported in Wuhan, China, in 2019 has evolved into a pandemic and public health emergency, leading to extensive fatalities and halting global economies. Older adults have emerged as a critically vulnerable population as earlier data suggests a disproportionately increased incidence of COVID-19 in this population, as well as worse health outcomes. Disease attenuating behaviors such as social distancing has been encouraged and mandated across different countries leading to downstream economic ramifications. This paper seeks to outline the economic implications of COVID-19 in the U.S. (particularly in terms of vocational, retail, and service industries), highlighting the role of nursing homes in disease dissemination. We also discuss potential costs associated with COVID-19 management focusing on the senior population who rely on Medicare benefits for health insurance.

Identification of high-risk human papillomavirus and Rb/E2F pathway genomic alterations in mutually exclusive subsets of colorectal neuroendocrine carcinoma.

Colorectal neuroendocrine carcinomas, both small cell and large cell types, are highly aggressive tumors with poor prognosis compared with colorectal adenocarcinoma. The molecular drivers of neuroendocrine carcinoma are best defined in small cell lung cancer, which shows near-universal genomic alterations in TP53 and RB1. The genetics of colorectal neuroendocrine carcinoma remain poorly understood; recent studies demonstrated infrequent RB1 alterations and genetics closely resembling colorectal adenocarcinoma. To better define the molecular pathogenesis of colorectal neuroendocrine carcinoma, we performed capture-based next-generation sequencing on 25 cases and evaluated for expression of p53, Rb, p16, and high-risk human papillomavirus (HR-HPV) subtypes using immunohistochemistry, in situ hybridization, and polymerase chain reaction. Rb/E2F pathway dysregulation was identified in nearly all cases (23/25, 92%) and occurred via three distinct mechanisms. First, RB1 genomic alteration was present in 56% (14/25) of cases and was accompanied by Rb protein loss, high p16 expression, and absence of HR-HPV; these cases also had frequent genomic alterations in TP53, the PI3K/Ras and Wnt pathways, as well as in DNA repair genes, with 4/14 cases being hypermutated. Second, 16% (4/25) of cases, all left-sided, had TP53 alteration without RB1 alteration; half of these harbored high-level amplifications in CCNE1 and MYC or MYCN and arose in patients with ulcerative colitis. Finally, 28% (7/25) of cases, all rectal or anal, lacked genomic alterations in RB1 or TP53 but were positive for HR-HPV. Our data demonstrate that Rb/E2F pathway dysregulation is essential in the pathogenesis of colorectal neuroendocrine carcinoma, akin to neuroendocrine carcinomas in other anatomic sites. Moreover, colorectal neuroendocrine carcinomas stratify into three distinct molecular subgroups, which can be differentiated based on Rb protein and HR-HPV status. HR-HPV infection represents a distinct mechanism for Rb and p53 inactivation in cases lacking genomic alterations in either gene. Differential treatment strategies for hypermutated and HPV-driven cases could improve patient outcomes.

Histopathological and molecular analysis of idiopathic pulmonary fibrosis lungs from patients treated with pirfenidone or nintedanib.

AIMS: The objective of this study was to quantify the impact of pirfenidone or nintedanib treatment on lung histopathology and molecular mediators of fibrosis in patients with idiopathic pulmonary fibrosis (IPF). METHODS AND RESULTS: We collected lung tissue from IPF patients at the time of lung transplantation. Histopathological changes were quantified using a blinded scoring method. Proteins associated with senescence or active TGF-ß were quantified in lung tissues by immunoblot and immunostaining. Histopathological quantification showed similar amounts of dense collagen fibrosis, fibroblast foci and alveolar macrophages in untreated or pirfenidone- or nintedanib-treated IPF patients. There was less diffuse alveolar damage and organising pneumonia in pirfenidone-treated IPF patients. Lungs of nintedanib-treated patients had a trend towards less lymphocytic interstitial infiltration. There was no difference in expression of p-SMAD3, p21 or p16 in the lungs of untreated, pirfenidone- or nintedanib-treated IPF patients. Alveolar epithelial cells, but not fibroblast foci, were immunoreactive to p16. Pirfenidone or nintedanib treatment did not inhibit activation of senescence programming in cultured lung epithelial cells mediated by hydrogen peroxide. CONCLUSION: Pirfenidone and nintedanib do not modulate expression of senescence markers, levels of p-SMAD3 or the amount of fibrosis in IPF lungs. Treated patients have less histopathological evidence of acute lung injury at the time of lung transplantation.

Significance of bronchiolocentric fibrosis in patients with histopathological usual interstitial pneumonia.

AIMS: To evaluate the clinical significance of bronchiolocentric fibrosis (BCF) in patients with a histopathological pattern of usual interstitial pneumonia (UIP). METHODS AND RESULTS: Two hundred and fifty-two patients with pathological UIP pattern were identified. Two hundred and fifteen of these patients (215 of 252) had the multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF). Prospectively defined clinical, radiological and pathological features (including BCF) were recorded, and peripheral blood MUC5B genotype and telomere length were measured. BCF was observed in 38% (96 of 252) of all patients and 33% (72 of 215) of IPF patients; its presence was associated with a non-IPF diagnosis on multivariate analysis (odds ratio = 3.71, 95% confidence interval = 1.68-8.19). BCF was not significantly associated with environmental exposures, gastroesophageal reflux, cigarette smoking or radiological patterns. There was no significant association of BCF with MUC5B genotype or telomere length. BCF has no significant impact on survival time. CONCLUSIONS: Most patients with BCF and a histopathological pattern of UIP have IPF. However, this combined fibrotic pattern is associated with a non-IPF multidisciplinary diagnosis, with approximately one-quarter of these patients being diagnosed as chronic hypersensitivity pneumonia or unclassifiable interstitial fibrosis. The presence of BCF in these patients is not significantly associated with presumed clinical risk factors for bronchiolocentric involvement, radiological findings, MUC5B genotype, telomere length or survival time.

Severe Silicosis in Engineered Stone Fabrication Workers - California, Colorado, Texas, and Washington, 2017-2019.

Silicosis is an incurable occupational lung disease caused by inhaling particles of respirable crystalline silica. These particles trigger inflammation and fibrosis in the lungs, leading to progressive, irreversible, and potentially disabling disease. Silica exposure is also associated with increased risk for lung infection (notably, tuberculosis), lung cancer, emphysema, autoimmune diseases, and kidney disease (1). Because quartz, a type of crystalline silica, is commonly found in stone, workers who cut, polish, or grind stone materials can be exposed to silica dust. Recently, silicosis outbreaks have been reported in several countries among workers who cut and finish stone slabs for countertops, a process known as stone fabrication (2-5). Most worked with engineered stone, a manufactured, quartz-based composite material that can contain >90% crystalline silica (6). This report describes 18 cases of silicosis, including the first two fatalities reported in the United States, among workers in the stone fabrication industry in California, Colorado, Texas, and Washington. Several patients had severe progressive disease, and some had associated autoimmune diseases and latent tuberculosis infection. Cases were identified through independent investigations in each state and confirmed based on computed tomography (CT) scan of the chest or lung biopsy findings. Silica dust exposure reduction and effective regulatory enforcement, along with enhanced workplace medical and public health surveillance, are urgently needed to address the emerging public health threat of silicosis in the stone fabrication industry.

Gene signatures common to allograft rejection are associated with lymphocytic bronchitis.

Lymphocytic bronchitis (LB) precedes chronic lung allograft dysfunction. The relationships of LB (classified here as Endobronchial or E-grade rejection) to small airway (A- and B-grade) pathologies are unclear. We hypothesized that gene signatures common to allograft rejection would be present in LB. We studied LB in two partially overlapping lung transplant recipient cohorts: Cohort 1 included large airway brushes (6 LB cases and 18 post-transplant referents). Differential expression using DESeq2 was used for pathway analysis and to define an LB-associated metagene. In Cohort 2, eight biopsies for each pathology subtype were matched with pathology-free biopsies from the same subject (totaling 48 samples from 24 subjects). These biopsies were analyzed by multiplexed digital counting of immune transcripts. Metagene score differences were compared by paired t tests. Compared to referents in Cohort 1, LB demonstrated upregulation of allograft rejection pathways, and upregulated genes in these cases characterized an LB-associated metagene. We observed statistically increased expression in Cohort 2 for this LB-associated metagene and four other established allograft rejection metagenes in rejection vs paired non-rejection biopsies for both E-grade and A-grade subtypes, but not B-grade pathology. Gene expression-based categorization of allograft rejection may prove useful in monitoring lung allograft health.

Identification of Diagnostic Criteria for Chronic Hypersensitivity Pneumonitis: An International Modified Delphi Survey.

RATIONALE: Current diagnosis of chronic hypersensitivity pneumonitis (cHP) involves considering a combination of clinical, radiological, and pathological information in multidisciplinary team discussions. However, this approach is highly variable with poor agreement between centers. OBJECTIVES: We aimed to identify diagnostic criteria for cHP that reach consensus among international experts. METHODS: A 3-round modified Delphi survey was conducted between April and August 2017. Forty-five experts in interstitial lung disease from 14 countries participated in the online survey. Diagnostic items included in round 1 were generated using expert interviews and literature review. During rounds 1 and 2, experts rated the importance of each diagnostic item on a 5-point Likert scale. The a priori threshold of consensus was ≥ 75% of experts rating a diagnostic item as very important or important. In the third round, experts graded the items that met consensus as important and provided their level of diagnostic confidence for a series of clinical scenarios. MEASUREMENTS AND MAIN RESULTS: Consensus was achieved on 18 of the 40 diagnostic items. Among these, experts gave the highest level of importance to the identification of a causative antigen, time relation between exposure and disease, mosaic attenuation on chest imaging, and poorly formed non-necrotizing granulomas on pathology. In clinical scenarios, the diagnostic confidence of experts in cHP was heightened by the presence of these diagnostic items. CONCLUSION: This consensus-based approach for the diagnosis of cHP represents a first step towards the development of international guidelines for the diagnosis of cHP.

Implementation of a Checklist to Reduce False-Positive Testing in Hospital-Acquired Clostridium Difficile Infection.

BACKGROUND: Clostridium difficile is a major pathogen responsible for nosocomial infectious diarrhea. After a spike in Clostridium difficile infection (CDI) cases, the focus team identified several cases of inappropriate sampling, i.e., asymptomatic patients being tested. We hypothesized that the inappropriate samples were leading to a high number of false-positive cases. We explored appropriate patient stool sampling as a strategy for reducing the number of asymptomatic cases in a 275-bed rural community hospital. METHODS: We conducted a prospective cohort study of inpatients to determine if appropriate stool sampling would result in a reduction in false positive Clostridium difficile cultures and decrease incidence of Clostridium difficile. We developed a checklist that would guide the nurse to improve the sampling process. RESULTS: The study implementation period ran from July through December 2016, with comparison to a control cohort in the prior six months. From Jan. 16 to May 15, the control group consisted of 461 inpatients, of which 89 tested positive for CDI 32.3 per 10,000 patient days. Of those 89 positive cases, 74 were identified as healthcare acquired infection (HAI) 26.8 per 10,000 patient days. Of these HAIs, 25 (33.8 percent) were inappropriate samples. In comparison, among the study period cohort of 277 inpatients, 46 inpatients tested positive for CDI 16.9 per 10,000 patient days, of which 26 were HAIs 9.5 per 10,000 patient days. During the study period, three samples (11.5 percent) were determined to be inappropriate. After the checklist implementation, the proportion of incorrect samples decreased from 33.8 percent to 11.5 percent. The number of HAI/patient days decreased form 0.024 percent to 0.08 percent. Similarly, the number of CDI/patient days also decreased from 0.295 percent to 0.15 percent. CONCLUSION: Implementation of a simple checklist prior to collection of stool sample proved to be effective in reducing the number of inappropriate samples sent for CDI testing, with a subsequent decrease in hospital acquired Clostridium difficile infections reported.