Search

Background: Practices of manual siphoning of fuel around the globe has exponentially increased the incidence of chemical pneumonitis. As evident by studies, chemical pneumonitis constitutes quite significant proportion of community-acquired pneumonia. In this case report, we follow up on the case of hydrocarbon pneumonitis along with its diagnostic uncertainty and treatment challenges. Case Presentation: A 66-year-old male presented with shortness of breath, fever, and hemoptysis after accidentally aspirating diesel while siphoning it from a generator. computed tomography pulmonary angiogram revealed bilateral pneumonitis and ruled out pulmonary embolism. He required high-flow oxygen initially due to extensive nature of pneumonia and was managed conservatively with broad-spectrum antibiotics and steroids. He recovered to discharge after 21 days. This represents a case of chemical, hydrocarbon (exogenous lipoid) pneumonitis, complicated by transudative pleural effusion and likely bacterial superinfection. Conclusion: Chemical pneumonitis is associated with varied symptoms and radiological presentation. Its treatment is essentially same as pneumonia caused by other pathogens. Timely diagnosis, escalation, and treatment can reduce the morbidity and mortality caused by these harmful insults.

RATIONALE: Shared symptoms and genetic architecture between COVID-19 and lung fibrosis suggests SARS-CoV-2 infection may lead to progressive lung damage.OBJECTIVES: The UKILD Post-COVID study interim analysis was planned to estimate the prevalence of residual lung abnormalities in people hospitalized with COVID-19 based on risk strata.METHODS: The Post-HOSPitalisation COVID Study (PHOSP-COVID) was used for capture of routine and research follow-up within 240 days from discharge. Thoracic CTs linked by PHOSP-COVID identifiers were scored for percentage of residual lung abnormalities (ground glass opacities and reticulations). Risk factors in linked CT were estimated with Bayesian binomial regression and risk strata were generated. Numbers within strata were used to estimate post-hospitalization prevalence using Bayesian binomial distributions. Sensitivity analysis was restricted to participants with protocol driven research follow-up.MEASUREMENTS AND MAIN RESULTS: The interim cohort comprised 3700 people. Of 209 subjects with linked CTs (median 119 days, interquartile range 83-155), 166 people (79.4%) had >10% involvement of residual lung abnormalities. Risk factors included abnormal chest X-ray (RR 1·21 95%CrI 1·05; 1·40), percent predicted DLcoCONCLUSIONS: Residual lung abnormalities were estimated in up to 11% of people discharged following COVID-19 related hospitalization. Health services should monitor at-risk individuals to elucidate long-term functional implications. This article is open access and distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).

Progressive fibrosing interstitial lung diseases (PFILDs) cause substantial morbidity and mortality. Antifibrotic agents slow progression, but most of the clinical need remains unmet. The archetypal PFILD is idiopathic pulmonary fibrosis (IPF). Chronic progression is driven by transforming growth factor (TGF-)β1 signalling. It is punctuated by inflammatory flares known as acute exacerbations (AE-IPF), which are associated with accelerated decline and high mortality. We hypothesized that acute injury responses underlying exacerbations and the mechanisms of chronic fibrosis overlap at the molecular level, via a cell surface assembly nucleated by galectin-3 that we term the ‘gal-3-fibrosome’. We focused upon a putative pro-inflammatory galectin-3 ligand, the CD98:integrin complex. Our data indicate CD98 and β1-integrin co-localise with galectin-3 within epithelial cells in IPF lung tissue, and within 40 nm in human lung tissue treated with TGF-β1 compared to controls. CD98 is required for interleukin (IL-)6 and IL-8 responses to biochemical and biophysical conditions mimicking stimuli of AE-IPF in vivo, ex vivo and in cells, and for an interstitial neutrophilic response in a mouse model. We demonstrate this pathway progresses via intracellular influx of Ca2+ mediated by TRPV4, and NF-κB activation, operating in positive feedback. Lastly we show the CD98- and galectin-3-dependence of IL-6 and IL-8 responses to the SARS-CoV-2 spike protein receptor binding domain and the conservation of this response pattern between lung epithelial cells and monocyte-derived macrophages. Taken together our findings identify CD98 as a key mediator of both pro-fibrotic and acute inflammatory responses in the lung with relevance to AE- and chronic progression of IPF, and the priming of fibrotic lungs for acute inflammatory responses. They similarly implicate CD98 and galectin-3 as mediators of COVID pneumonitis and worse outcomes in ILD patients with COVID.

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal disorder with a variable disease trajectory. The aim of this study was to assess the potential of neutrophil-to-lymphocyte ratio (NLR) to predict outcomes in IPF.We adopted a two-stage discovery (n = 71) and validation (n = 134) design using patients from the UCL partners (UCLp) cohort. We then combined discovery and validation cohorts and included an additional 794 people with IPF, using real-life data from 5 other UK centers, to give a combined cohort of 999 patients. Data were collected from patients presenting over a 13-year period (2006-2019) with mean follow up of 3.7 years (censoring: 2018-2020).In the discovery analysis, we showed that high values of NLR (/ = 2.9 vs 2.9) were associated with increased risk of mortality in IPF (HR 2.04, 95% CI 1.09-3.81, n = 71, p = 0.025). This was confirmed in the validation (HR 1.91, 95% CI 1.15-3.18, n = 134, p = 0.0114) and combined cohorts (HR 1.65, n = 999, 95% CI 1.39-1.95; p 0·0001). NLR correlated with GAP stage and GAP index (p 0.0001). Stratifying patients by NLR category (low/high) showed significant differences in survival for GAP stage 2 (p 0.0001), however not for GAP stage 1 or 3. In a multivariate analysis, a high NLR was an independent predictor of mortality/progression after adjustment for individual GAP components and steroid/anti-fibrotic use (p 0·03). Furthermore, incorporation of baseline NLR in a modified GAP-stage/index, GAP-index/stage-plus, refined prognostic ability as measured by concordance (C)-index.We have identified NLR as a widely available test that significantly correlates with lung function, can predict outcomes in IPF and refines cohort staging with GAP. NLR may allow timely prioritisation of at-risk patients, even in the absence of lung function.Breathing Matters, GSK, CF Trust, BLF-Asthma, MRC, NIHR Alpha-1 Foundation.

SummaryBackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive, fatal disorder with a variable disease trajectory. The aim of this study was to assess the potential of neutrophil-to-lymphocyte ratio (NLR) to predict outcomes for people with IPF.MethodWe adopted a two-stage discovery and validation design using patients from the UCL partners (UCLp) cohort. For the discovery analysis, we included 71 patients from UCLH. In the validation analysis, we included 928 people with IPF, using real-life data from UCLH and 5 other UK centres. Data were collected from patients presenting over a 13-year period with a mean follow up time of 3.7 years.FindingsIn the discovery analysis, we showed that values of NLR (/=2.9) were associated with increased risk of mortality (HR 2.04, 95% CI 1.09-3.81; p=0.025). In the validation cohort we confirmed this association of high NLR with mortality (HR 1.65, 95% CI 1.39-1.95; pInterpretationWe have identified NLR as a widely available test that significantly correlates with lung function, can predict outcomes in IPF and refines clinical GAP-staging. NLR may help ILD specialist centres prioritise at risk patients in a timely way, even in the absence of lung function.

Interstitial lung disease is a known complication of rheumatoid arthritis, with a lifetime risk of developing the disease in any individual of 7·7%. We aimed to assess the safety, tolerability, and efficacy of pirfenidone for the treatment of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD).TRAIL1 was a randomised, double-blind, placebo-controlled, phase 2 trial done in 34 academic centres specialising in interstitial lung disease in four countries (the UK, the USA, Australia, and Canada). Adults aged 18-85 years were eligible for inclusion if they met the 2010 American College of Rheumatology and European Alliance of Associations for Rheumatology criteria for rheumatoid arthritis and had interstitial lung disease on a high-resolution CT scan imaging and, when available, lung biopsy. Exclusion criteria include smoking, clinical history of other known causes of interstitial lung disease, and coexistant clinically significant COPD or asthma. Patients were randomly assigned (1:1) to receive 2403 mg oral pirfenidone (pirfenidone group) or placebo (placebo group) daily. The primary endpoint was the incidence of the composite endpoint of a decline from baseline in percent predicted forced vital capacity (FVC%) of 10% or more or death during the 52-week treatment period assessed in the intention-to-treat population. Key secondary endpoints included change in absolute and FVC% over 52 weeks, the proportion of patients with a decline in FVC% of 10% or more, and the frequency of progression as defined by Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02808871.From May 15, 2017, to March 31, 2020, 231 patients were assessed for inclusion, of whom 123 patients were randomly assigned (63 [51%] to the pirfenidone group and 60 [49%] to the placebo group). The trial was stopped early (March 31, 2020) due to slow recruitment and the COVID-19 pandemic. The difference in the proportion of patients who met the composite primary endpoint (decline in FVC% from baseline of 10% or more or death) between the two groups was not significant (seven [11%] of 63 patients in the pirfenidone group vs nine [15%] of 60 patients in the placebo group; OR 0·67 [95% CI 0·22 to 2·03]; p=0·48). Compared with the placebo group, patients in the pirfenidone group had a slower rate of decline in lung function, measured by estimated annual change in absolute FVC (-66 vs -146; p=0·0082) and FVC% (-1·02 vs -3·21; p=0·0028). The groups were similar with regards to the decline in FVC% by 10% or more (five [8%] participants in the pirfenidone group vs seven [12%] in the placebo group; OR 0·52 [95% CI 0·14-1·90]; p=0·32) and the frequency of progression as defined by OMERACT (16 [25%] in the pirfenidone group vs 19 [32%] in the placebo group; OR 0·68 [0·30-1·54]; p=0·35). There was no significant difference in the rate of treatment-emergent serious adverse events between the two groups, and there were no treatment-related deaths.Due to early termination of the study and underpowering, the results should be interpreted with caution. Despite not meeting the composite primary endpoint, pirfenidone slowed the rate of decline of FVC over time in patients with RA-ILD. Safety in patients with RA-ILD was similar to that seen in other pirfenidone trials.Genentech.

ObjectiveAlpha-1 antitrypsin deficiency (AATD) is a common, potentially lethal inborn disorder caused by mutations in alpha-1 antitrypsin (AAT). Homozygosity for the ‘Pi*Z’ variant of AAT (Pi*ZZ genotype) causes lung and liver disease, whereas heterozygous ‘Pi*Z’ carriage (Pi*MZ genotype) predisposes to gallstones and liver fibrosis. The clinical significance of the more common ‘Pi*S’ variant remains largely undefined and no robust data exist on the prevalence of liver tumours in AATD.DesignBaseline phenotypes of AATD individuals and non-carriers were analysed in 482 380 participants in the UK Biobank. 1104 participants of a multinational cohort (586 Pi*ZZ, 239 Pi*SZ, 279 non-carriers) underwent a comprehensive clinical assessment. Associations were adjusted for age, sex, body mass index, diabetes and alcohol consumption.ResultsAmong UK Biobank participants, Pi*ZZ individuals displayed the highest liver enzyme values, the highest occurrence of liver fibrosis/cirrhosis (adjusted OR (aOR)=21.7 (8.8–53.7)) and primary liver cancer (aOR=44.5 (10.8–183.6)). Subjects with Pi*MZ genotype had slightly elevated liver enzymes and moderately increased odds for liver fibrosis/cirrhosis (aOR=1.7 (1.2–2.2)) and cholelithiasis (aOR=1.3 (1.2–1.4)). Individuals with homozygous Pi*S mutation (Pi*SS genotype) harboured minimally elevated alanine aminotransferase values, but no other hepatobiliary abnormalities. Pi*SZ participants displayed higher liver enzymes, more frequent liver fibrosis/cirrhosis (aOR=3.1 (1.1–8.2)) and primary liver cancer (aOR=6.6 (1.6–26.9)). The higher fibrosis burden was confirmed in a multinational cohort. Male sex, age ≥50 years, obesity and the presence of diabetes were associated with significant liver fibrosis.ConclusionOur study defines the hepatobiliary phenotype of individuals with the most relevant AATD genotypes including their predisposition to liver tumours, thereby allowing evidence-based advice and individualised hepatological surveillance.

IntroductionThe COVID-19 pandemic has led to over 100 million cases worldwide. The UK has had over 4 million cases, 400 000 hospital admissions and 100 000 deaths. Many patients with COVID-19 suffer long-term symptoms, predominantly breathlessness and fatigue whether hospitalised or not. Early data suggest potentially severe long-term consequence of COVID-19 is development of long COVID-19-related interstitial lung disease (LC-ILD).Methods and analysisThe UK Interstitial Lung Disease Consortium (UKILD) will undertake longitudinal observational studies of patients with suspected ILD following COVID-19. The primary objective is to determine ILD prevalence at 12 months following infection and whether clinically severe infection correlates with severity of ILD. Secondary objectives will determine the clinical, genetic, epigenetic and biochemical factors that determine the trajectory of recovery or progression of ILD. Data will be obtained through linkage to the Post-Hospitalisation COVID platform study and community studies. Additional substudies will conduct deep phenotyping. The Xenon MRI investigation of Alveolar dysfunction Substudy will conduct longitudinal xenon alveolar gas transfer and proton perfusion MRI. The POST COVID-19 interstitial lung DiseasE substudy will conduct clinically indicated bronchoalveolar lavage with matched whole blood sampling. Assessments include exploratory single cell RNA and lung microbiomics analysis, gene expression and epigenetic assessment.Ethics and disseminationAll contributing studies have been granted appropriate ethical approvals. Results from this study will be disseminated through peer-reviewed journals.ConclusionThis study will ensure the extent and consequences of LC-ILD are established and enable strategies to mitigate progression of LC-ILD.

The factors determining disease course and survival in fibrotic hypersensitivity pneumonitis (fHP) have not been fully elucidated.The aim of this study was to describe the characteristics of patients with fHP in a real-world cohort and investigate factors associated with worse outcomes. We aimed to explore the use of neutrophil to lymphocyte ratio (NLR) and peripheral blood monocyte levels in predicting mortality.MethodsA retrospective, multicentre, observational UK cohort study.ResultsPatients with fHP were significantly younger than those with idiopathic pulmonary fibrosis (IPF) (median age fHP 73 vs IPF 75 years) and were much more likely to be woman (fHP 61% vs IPF 26%). In almost half of all fHP cases (49%, n=104/211), no causative antigen was identified from either the history or specific antigen testing. Overall, fHP was associated with a better survival than IPF, although median survival of both groups was poor (fHP 62 months vs IPF 52 months).IPF survival in patients with a high NLR was significantly lower than those with a low NLR (44 vs 83 months). A monocyte count ≥0.95 K/uL also predicted significantly poorer outcomes for patients with IPF compared with ConclusionsAlthough fHP has a statistically lower mortality than IPF, absolute survival time of both conditions is poor. High baseline NLR and absolute monocyte counts predict worse survival in IPF but not in fHP, highlighting the potential for divergence in their pathogenic mechanisms.

A persistent unexplained eosinophilia is relatively unusual and has a number of causes of which allergy and infection with helminthic parasites are the most common diagnoses. Less common causes include idiopathic hypereosinophilic syndrome (HES), eosinophilic granulomatosis with polyangiitis (EGPA) and single organ conditions such as eosinophilic gastrointestinal disease (EGID) (1) . Although occasionally caused by myeloproliferative neoplasm in most cases eosinophilia is due to excess production of growth factors, particularly interleukin-5, by bystander cells which are often lymphoid in nature. Sometimes an environmental trigger can be identified, but the underlying cause of the eosinophilia often remains obscure.

BackgroundMany patients with alpha-1 antitrypsin deficiency (A1ATD) receive care in respiratory clinics without access to specialist hepatology expertise. Liver disease can develop asymptomatically, and non-invasive markers of fibrosis may help identify patients who require definitive assessment with liver biopsy. We evaluated the utility of non-invasive markers of liver fibrosis in A1ATD to guide testing in settings without ready access to hepatology expertise.MethodsPatients attending the London A1ATD service undergo assessment using blood tests to calculate the ‘APRI’ and ‘FIB-4’ score, liver ultrasound and Fibroscan. Liver biopsy is offered to patients who have abnormal liver function tests with abnormal liver ultrasound and/or liver stiffness >6 kPa on Fibroscan. Liver biopsies were assessed for the presence of A1AT, steatosis, fibrosis and inflammation.Results75 patients with A1ATD had results for analysis, 56% were female, age 16–82 years. 75% of patients had Fibroscan 8 kPa. There was a significant correlation between FIB-4 and Fibroscan (r=0.244, p=0.035). Fibroscan >6 kPa corresponded to a FIB-4 score of >1.26. However, FIB-4 >1.26 had poor sensitivity (47%), specificity (32%) and positive-predictive value (PPV; 36%) to identify Fibroscan >6 kPa. The negative-predictive value (NPV) was stronger at 81%. APRI data were similar. Twelve patients underwent liver biopsy, with 11 reports available for analysis. Six had FIB-4 scoresConclusionA combination of liver ultrasound and non-invasive fibrosis tests can help identify patients with A1ATD liver injury. However, APRI and FIB-4 scores alone had poor sensitivity and specificity to justify use as an independent tool for liver pathology in A1ATD.

Funder: Foundation for the National Institutes of Health; FundRef: http://dx.doi.org/10.13039/100000009, OBJECTIVES: To establish a database network for the study of alpha-1 antitrypsin deficiency (AATD) and compare the results to CT lung density as the most direct measure of emphysema. DESIGN: A central electronic database was established to permit the upload of anonymised patient data from remote sites. Prospectively collected CT data were recorded onto disc, anonymised, analysed at the coordinating centre and compared with the clinical features of the disease. SETTING: Tertiary referral centres with expertise in the management of AATD focused on academic Biomedical Research Units and Wellcome Clinical Research Facilities. PARTICIPANTS: Data were collected from 187 patients over 1 year from eight UK academic sites. This included patient demographics, postbronchodilator physiology, health status and CT. Analysis was undertaken at the coordinating centre in Birmingham. RESULTS: Patient recruitment in the 12 months reached 94% of target (set at 200) covering the whole spectrum of the disease from those with normal lung function to very severe chronic obstructive lung disease. CT scan suitable for analysis was available from 147 (79%) of the patients. CT density, analysed as the threshold for the lowest 15% of lung voxels, showed statistically significant relationships with the objective physiological parameters of lung function as determined by spirometric Global Initiative for Chronic Obstructive Lung Disease (GOLD) severity staging (p

Science advances 6(43), eabc1370 (1-14) (2020). doi:10.1126/sciadv.abc1370, The serpinopathies are among a diverse set of conformational diseases that involve the aberrant self-association of proteins into ordered aggregates. α$_1$-Antitrypsin deficiency is the archetypal serpinopathy and results from the formation and deposition of mutant forms of α$_1$-antitrypsin as “polymer” chains in liver tissue. No detailed structural analysis has been performed of this material. Moreover, there is little information on the relevance of well-studied artificially induced polymers to these disease-associated molecules. We have isolated polymers from the liver tissue of Z α$_1$-antitrypsin homozygotes (E342K) who have undergone transplantation, labeled them using a Fab fragment, and performed single-particle analysis of negative-stain electron micrographs. The data show structural equivalence between heat-induced and ex vivo polymers and that the intersubunit linkage is best explained by a carboxyl-terminal domain swap between molecules of α$_1$-antitrypsin., Published by Assoc., Washington, DC [u.a.]

Background Alveolar epithelial cell dysfunction plays an important role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), but remains incompletely understood. Some monogenic forms of pulmonary fibrosis are associated with expression of mutant surfactant protein C (SFTPC). The commonest pathogenic mutant, I73T, mislocalises to the alveolar epithelial cell plasma membrane and displays a toxic gain of function. Because the mechanisms explaining the link between this mutant and IPF are incompletely understood, we sought to interrogate SFTPC trafficking in health and disease to understand the functional significance of SFTPC-I73T relocalisation. Methods We performed mechanistic analysis of SFTPC trafficking in a cell model that reproduces the in vivo phenotype and validated findings in human primary alveolar organoids. Results We show that wild-type SFTPC takes an unexpected indirect trafficking route via the plasma membrane and undergoes the first of multiple cleavage events before reaching the multivesicular body (MVB) for further processing. SFTPC-I73T takes this same route, but its progress is retarded both at the cell surface and due to failure of trafficking into the MVB. Unable to undergo onward trafficking, it is recycled to the plasma membrane as a partially cleaved intermediate. Conclusion These data show for the first time that all SFTPC transits the cell surface during normal trafficking, and the I73T mutation accumulates at the cell surface through both retarded trafficking and active recycling. This understanding of normal SFTPC trafficking and how the I73T mutant disturbs it provides novel insight into SFTPC biology in health and disease, and in the contribution of the SFTPC mutant to IPF development., Studying how SFTPC mutations cause familial pulmonary fibrosis may help us develop new therapies for IPF. By studying a pathogenic mutation, this study reveals new insights into SFTPC handling in alveolar cells and how this is perturbed in disease. https://bit.ly/344VUhm

Chronic obstructive pulmonary disease (COPD) constitutes a major cause of morbidity and mortality. Genome wide association studies have shown significant associations between airflow obstruction or COPD with a non-synonymous SNP in the TNS1 gene, which encodes tensin1. However, the expression, cellular distribution and function of tensin1 in human airway tissue and cells are unknown. We therefore examined these characteristics in tissue and cells from controls and people with COPD or asthma. Airway tissue was immunostained for tensin1. Tensin1 expression in cultured human airway smooth muscle cells (HASMCs) was evaluated using qRT-PCR, western blotting and immunofluorescent staining. siRNAs were used to downregulate tensin1 expression. Tensin1 expression was increased in the airway smooth muscle and lamina propria in COPD tissue, but not asthma, when compared to controls. Tensin1 was expressed in HASMCs and upregulated by TGFβ1. TGFβ1 and fibronectin increased the localisation of tensin1 to fibrillar adhesions. Tensin1 and α-smooth muscle actin (αSMA) were strongly co-localised, and tensin1 depletion in HASMCs attenuated both αSMA expression and contraction of collagen gels. In summary, tensin1 expression is increased in COPD airways, and may promote airway obstruction by enhancing the expression of contractile proteins and their localisation to stress fibres in HASMCs.

Ion mobility mass spectrometry (IM-MS) is a fast and sample-efficient method for analysing the gas phase conformation of proteins and protein complexes. Subjecting proteins to increased collision energies prior to ion mobility separation can directly probe their unfolding behaviour. Recent work in the field has utilised this approach to evaluate the effect of small ligand binding upon protein stability, and to screen compounds for drug discovery. Its general applicability for high-throughput screening will, however, depend upon new analytical methods to make the approach scalable. Here we describe a fully automated program, called Benthesikyme, for summarising the ion mobility results from such experiments. The program automatically creates collision induced unfolding (CIU) fingerprints and summary plots that capture the increase in collision cross section and the increase in conformational flexibility of proteins during unfolding. We also describe a program, based on a genetic algorithm, for the deconvolution of arrival time distributions from the CIU data. This multicomponent analysis method was developed to require as little user input as possible. Aside from the IM-MS data, the only input required is an estimate of the number of conformational families to be fitted to the data. In cases where the appropriate number of conformational families is unclear, the automated procedure means it is straightforward to repeat the analysis for several values and optimize the quality of the fit. We have employed our new methodology to study the effects of peptide binding to α1-antitrypsin, an abundant human plasma protein whose misfolding exemplifies a group of conformational diseases termed the serpinopathies. Our analysis shows that interaction with the peptide stabilises the protein and reduces its conformational flexibility. The previously unresolved patterns of unfolding detected by the deconvolution algorithm will allow us to set up a fully automated screen for new ligand molecules with similar properties.

Introduction Hypersensitivity pneumonitis is a disease triggered by repeated inhalation and sensitisation to a variety of antigenic stimuli in susceptible individuals. It can be challenging to distinguish idiopathic pulmonary fibrosis (IPF) from fibrotic hypersensitivity pneumonitis (fHP). Predictors of disease progression are not well defined. Neutrophil:Lymphocyte ratio (NLR) and monocyte count have shown promise in providing prognostic value in IPF, but have not been examined in HP. Objectives To further characterise a large, UK-based, multicentre, retrospective cohort of patients with HP to enable clinical phenotyping and investigation of factors that might predict survival. Methods A multicentre evaluation of clinical data of IPF and HP patients presenting to the interstitial lung disease clinics at the North Bristol NHS Trust, University Hospitals of Leicester NHS Trust, Taunton and Somerset NHS Foundation Trust and the Royal Devon & Exeter NHS Foundation Trust was undertaken. All patients had received multidisciplinary team evaluation between 2005 and 2018. Mann-Whitney U tests and Kaplan Meier survival curve analysis were used as appropriate. Results In a cohort of 493 IPF patients, the survival of patients with a high NLR was significantly lower than in those with a low NLR (median survival 36 months vs 62 months; Hazard Ratio (HR) 1.7, 95% C.I. 1.3–2.4, p=0.0002). NLR did not predict survival in a cohort of 182 HP patients. Monocyte count was statistically higher in IPF vs HP patients (median monocyte count 0.7 K/ul IPF n=408 vs 0.6 HP n=76 p=0.0051). For IPF only, monocyte count >0.95 K/ul predicted significantly poorer outcome (median survival 37 months vs 74 months; HR 2.0, 95% C.I. 1.3 – 3.2, p=0.0119); monocyte count was within normal range for the majority of HP patients. IPF patients also had significantly faster decline in both FVC and DLCOthan HP patients (p=0.007 and 0.018, respectively). Conclusion Further analysis of our fHP cohort has revealed that cellular biomarkers which may predict survival in IPF, namely Neutrophil:Lymphocyte ratio and monocyte count, do not significantly predict a poorer outcome in HP. More detailed interrogation of patient data may reveal other key baseline measures which will support clinical management.

Background Galectin-3 critically mediates experimental fibrosis, potentiating pro-fibrotic effects of transforming growth factor (TGF)-β1, and is highly expressed in idiopathic pulmonary fibrosis (IPF). Therefore, a galectin-3 small molecule glycomimetic antagonist is in Phase 2B trials. Galectin-3 may mediate pathogenesis in alveolar epithelial cells (AECs) and myofibroblasts by nucleating a macromolecular complex assembly on the cell surface. We term this the ‘gal-3-fibrosome’. In addition to galectin-3, putative components include CD98:β1-integrin complex and TGF-β receptor II (TGF-βRII). Through multiple experimental techniques, we have established evidence for the gal-3-fibrosome hypothesis in AECs. Aim Characterise mRNA and protein levels and co-localisation of galectin-3 with CD98:β1-integrin and TGF-βRII, basally and with pro-fibrotic stimulation in non-fibrotic control (NFC) and IPF contexts ex vivo. Methods We studied the expression levels of galectin-3, CD98 heavy chain (CD98hc) and β1-integrin at mRNA and protein levels, and their co-localisation. We characterised lung tissue and low passage IPF and NFC lung myofibroblasts (passage 4–5), basally and with TGF-β1 stimulation. Results IPF lung tissue stained positively for galectin-3, β1-integrin and CD98 but NFC lung tissue did not. TGF-β1 treatments increased mRNA levels for transcripts of β1-integrin and CD98hc, but not galectin-3 in human lung tissue cultured ex vivo. More pronounced differential responses were detected at the protein level in lung myofibroblasts purified ex vivo: protein levels of β1-integrin and CD98hc increased, whilst galectin-3 levels dropped. There was a concomitant decrease in galectin-3 co-localisation with β1-integrin and CD98hc in NFC lung myofibroblasts. However, no alteration in co-localisation was observed in IPF-derived lung myofibroblasts. Conclusion Putative gal-3-fibrosome components co-localise at the cellular level in IPF lung tissue. Co-localisation is also evident in IPF lung myofibroblasts purified ex vivo. Our data indicate this is mediated by increased transcription of mRNA encoding CD98hc and β1-integrin but that observed galectin-3 increases are more likely related to stabilisation at the protein level. Our unexpected findings regarding reductions in galectin-3 levels with TGF-β1 treatment in human NFC lung tissue and myofibroblasts ex vivo are consistent with a negative feedback loop restricting gal-3-fibrosome formation. This may then be counteracted by increased gal-3-fibrosome stabilisation in IPF to enhance pathogenic TGF-β1 signalling.

Introduction Hypersensitivity pneumonitis is a complex syndrome believed to result from repeated inhalation and sensitisation to a variety of antigenic stimuli. The majority of cases are classified as chronic and may result in fibrotic progression which can be hard to distinguish from idiopathic pulmonary fibrosis (IPF). Precise aetiology and optimal management strategies are less well defined than for IPF, although clinical trials exploring efficacy of pirfenidone (NCT02496182) and nintedanib (NCT02999178) are in progress. Objectives To establish a large, UK-based, multicentre, retrospective cohort of patients with cHP to facilitate detailed investigation of patient demographics, management and prognosis. Methods Multicentre evaluation of clinical data for patients presenting to the interstitial lung disease clinics at the North Bristol NHS Trust, University Hospitals of Leicester NHS Trust, Taunton and Somerset NHS Foundation Trust and the Royal Devon & Exeter NHS Foundation Trust between 2005 and 2018. Basic demographics and survival were compared using chi-square test with Yates correction (gender), Mann-Whitney U-test (age at presentation) and Kaplan-Meier Survival analysis in Graphpad Prism. Results In total, 397 patients with a diagnosis of cHP were identified, compared with 1068 patients with IPF. There was a significant difference in age at diagnosis between cHP and IPF (median 72.0 vs 75.6, p Conclusions Despite challenges in diagnosing cHP (as demonstrated by Walsh et al1 in their review of UK MDT agreement where HP has only a fair kappa score of 0.29) and in line with published literature, our cHP cohort has a female preponderance and is associated with better survival than IPF. This cohort will provide a crucial resource for more detailed analysis of patient data (e.g. spirometry and response to therapy). Reference Walsh SL, et al. Lancet Respir Med2016;4:557–65.

Studies to identify novel immune-regulatory functions of active vitamin D (1,25(OH)(2)D3) in human CD4(+) T cells revealed that 1,25(OH)(2)D3 potently induced expression of the gene SERPINA1, encoding the anti-protease α-1-antitrypsin. We confirmed α-1-antitrypsin protein expression by 1,25(OH)(2)D3-treated CD4(+) T cells, but not in CD8(+) T cells or monocytes. α-1-Antitrypsin promotes anti-inflammatory IL-10 synthesis in other immune cell populations. We therefore investigated its immune-regulatory effects in CD4(+) T cells. Plasma-derived α-1-antitrypsin drove IL-10 synthesis by CD4(+) T cells, which was not dependent on anti-protease activity, but appeared to require a serum-binding factor, since this could not be achieved with recombinant protein. α-1-Antitrypsin is reported to bind complement components, which regulate T cell function. A role for this interaction was therefore probed. Plasma-derived, but not recombinant α-1-antitrypsin contained C3a. Surface Plasmon Resonance and Microscale Thermophoresis demonstrated α-1-antitrypsin binding to C3a. Addition of C3a to CD4(+) T cells cultured with recombinant α-1-antitrypsin restored induction of IL-10, whereas neutralisation of C3a abrogated IL-10 induced by plasma-derived α-1-antitrypsin. To interrogate an endogenous role for the α-1-antitrypsin-C3a axis in 1,25(OH)(2)D3-driven CD4(+) T cell IL-10 synthesis, we treated cells from healthy or α-1-antitrypsin-deficient individuals (which transcribe SERPINA1 but do not secrete protein) with 1,25(OH)(2)D3. A significant correlation was identified between SERPINA1 and IL10 gene expression in healthy donor CD4(+) T cells, which was absent in cells from α-1-antitrypsin-deficient individuals. Therefore, α-1-antitrypsin is required for 1,25(OH)(2)D3-induced IL-10 expression in CD4(+) T cells, interacting with C3a to drive IL-10 expression.

Children randomised in the neonatal period to high frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation (CMV) in the United Kingdom Oscillation study (UKOS) had superior lung function at 11 to 14 years of age. During HFOV, much smaller tidal volumes, but a higher mean airway distending pressure is delivered, hence, a possible explanation for a volume dependent effect on long term lung function could be an increase in inflammation in response to higher tidal volumes and strains. We tested that hypothesis by assessing interleukin-6 (IL-6) and -8 (IL-8) release from A549 alveolar analogue cells following biaxial mechanical strain applied at 0.5 Hz occurring during conditions mimicking strain during CMV (5–20% strain) and conditions mimicking strain during HFOV (17.5% ± 2.5% strain) for up to 4 h. Cyclic strain of 5–20%, occurring during CMV, increased levels of both IL-6 and IL-8 compared to unstrained controls, while 17.5% ± 2.5% strain, occurring during HFOV, was associated with significantly lower levels of IL-6 (46.31 ± 2.66 versus 56.79 ± 3.73 pg/mL) and IL-8 (1340.2 ± 74.9 versus 2522 ± 248 pg/mL) secretion compared to conditions occurring during CMV at four hours. These results may provide a possible explanation for the superior lung function in 11–14-year-old children who had been supported in the neonatal period by HFOV.

The growth of publicly available data informing upon genetic variations, mechanisms of disease, and disease subphenotypes offers great potential for personalized medicine. Computational approaches are likely required to assess a large number of novel genetic variants. However, the integration of genetic, structural, and pathophysiological data still represents a challenge for computational predictions and their clinical use. We addressed these issues for alpha-1-antitrypsin deficiency, a disease mediated by mutations in the SERPINA1 gene encoding alpha-1-antitrypsin. We compiled a comprehensive database of SERPINA1 coding mutations and assigned them apparent pathological relevance based upon available data. "Benign" and "pathogenic" variations were used to assess performance of 31 pathogenicity predictors. Well-performing algorithms clustered the subset of variants known to be severely pathogenic with high scores. Eight new mutations identified in the ExAC database and achieving high scores were selected for characterization in cell models and showed secretory deficiency and polymer formation, supporting the predictive power of our computational approach. The behavior of the pathogenic new variants and consistent outliers were rationalized by considering the protein structural context and residue conservation. These findings highlight the potential of computational methods to provide meaningful predictions of the pathogenic significance of novel mutations and identify areas for further investigation.

Primary pneumothorax affects 0.01% of the population. 10% of cases have a family history of pneumothorax but in the majority, a definitive genetic diagnosis is not made. We report a 26-year-old, white British woman who presented with left apical pneumothorax (figure 1a). Previously, she had migraines, multiple stress fractures in her right foot, myopia, easy bruising, lumbar scoliosis and spontaneous dislocation of the right patella. She had no previous history of pneumothoraces or any other respiratory problems, and had never smoked.

Idiopathic pulmonary fibrosis (IPF) is possibly the most rapidly progressive, chronic fibrosing condition in any organ. It is associated with a median survival of 3 years from diagnosis. The overall incidence of diagnosed IPF is increasing, in part as awareness of the diagnosis increases. Indeed, recent epidemiologic findings from the Respiratory Health of the Nation study in the United Kingdom indicate that IPF is twice as common as previously believed, with around 0.5 cases diagnosed per 1,000 of the UK population (1). Moreover, although it is considered a rare disease, IPF is strongly associated with ageing. In patients ≥70 years in age, its incidence is estimated between 1 and 4 per 1,000, and it is responsible for 1% of deaths in the United Kingdom (1–3). Clinical need remains under-served in terms of its diagnosis and effective treatment. Nevertheless, the direction of travel over recent years in both these aspects is encouraging. The evolution of guidelines and algorithms for multidisciplinary diagnosis of IPF (4) has been associated with increased consistency between specialist centres internationally (5). This appears to be accompanied by good identification of cases in which typically ‘IPF-like’ disease behaviour – progressive decline despite therapeutic intervention – is predicted, allowing proactive management planning. Within this ‘typical’ picture of disease progression, heterogeneity is increasingly recognized at both clinical and molecular levels, allowing the possibility of more personalized care in the future (6).

Aims A follow-up study of a randomised trial, the United Kingdom Oscillation Study (UKOS) comparing conventional ventilation (CMV) to high frequency oscillation ventilation (HFOV) immediately after birth,(1) demonstrated lung function was significantly better at age 11–14 years in the HFOV group.(2) During CMV, the inflation volumes are approximately two to three times larger than those during HFOV. Cyclical mechanical stretch (CMS) applied to A549 cells (type II alveolar cell analogues) has been shown to result in interleukin-8 release which increases with increasing basement membrane stretch.(3) We, therefore, hypothesised that during ‘CMV’ there would be greater interleukin release compared with ‘HFOV’, from type II alveolar cells. Methods A549 cells were grown in Dulbecco’s modified Eagle’s medium (DMEM) on flexible collagen based plates. Adherent cells were subjected to CMS conditions modelling CMV or HFOV using a Flexcell 4000T machine. Conditioned medium was analysed by ELISA to determine IL-6 and IL-8 levels following CMS for two and four hours. The results were compared with levels measured from control A549 cells that were unstretched or constantly stretched to 5% and 20% over the same time course. Results The mean fold increase of IL-8 release compared with the un-stretched control samples was higher in the ‘CMV’ compared with the ‘HFOV’ model at two hours (1.59, standard deviation (SD) 0.17 versus 0.91, SD 0.31, p Conclusion Conditions modelling CMV resulted in greater interleukin release in lung epithelial cells relative to those modelling HFOV. We propose that this may disrupt lung development in neonates supported by CMV rather than HFOV resulting in inferior lung function at follow-up.

As with all proteins, the structural behavior of α 1 -antitrypsin determines its function. However, the functional mechanism by which α 1 -antitrypsin inhibits its target proteases is unusually dynamic, relating to its folding and the potential for it to adopt more thermodynamically stable forms than its native conformation. Alpha1-antitrypsin deficiency arises most commonly as a result of point mutations that affect the structure and dynamic behavior of α 1 -antitrypsin in solution during and after folding. Understanding the dynamic structural behavior of α 1 -antitrypsin, therefore, explains both how it functions in health and how it drives disease. Consequently, it identifies novel therapeutic strategies to treat the underlying pathogenic mechanisms in α 1 -antitrypsin deficiency.

Misfolding and conformational diseases are increasing in prominence and prevalence. Both misfolding and ‘postfolding’ conformational mechanisms can contribute to pathogenesis and can coexist. The different contexts of folding and native state behavior may have implications for the development of therapeutic strategies. α1-antitrypsin deficiency illustrates how these issues can be addressed with therapeutic approaches to rescue folding, ameliorate downstream consequences of aberrant polymerization and/or maintain physiological function. Small-molecule strategies have successfully targeted structural features of the native conformer. Recent developments include the capability to follow solution behavior of α1-antitrypsin in the context of disease mutations and interactions with drug-like compounds. Moreover, preclinical studies in cells and organisms support the potential of manipulating cellular response repertoires to process misfolded and polymer states.

Since its discovery 50 years ago, α1-antitrypsin deficiency has represented a case study in molecular medicine, with careful clinical characterisation guiding genetic, biochemical, biophysical, structural, cellular, and in vivo studies. Here we highlight the milestones in understanding the disease mechanisms and show how they have spurred the development of novel therapeutic strategies. α1-Antitrypsin deficiency is an archetypal conformational disease. Its pathogenesis demonstrates the interplay between protein folding and quality control mechanisms, with aberrant conformational changes causing liver and lung disease through combined loss- and toxic gain-of-function effects. Moreover, α1-antitrypsin exemplifies the ability of diverse proteins to self-associate into a range of morphologically distinct polymers, suggesting a mechanism for protein and cell evolution.

BACKGROUND: Diffuse parenchymal lung disease represents a diverse and challenging group of pulmonary disorders. A consistent diagnostic approach to diffuse parenchymal lung disease is crucial if clinical trial data are to be applied to individual patients. We aimed to evaluate inter-multidisciplinary team agreement for the diagnosis of diffuse parenchymal lung disease.METHODS: We did a multicentre evaluation of clinical data of patients who presented to the interstitial lung disease unit of the Royal Brompton and Harefield NHS Foundation Trust (London, UK; host institution) and required multidisciplinary team meeting (MDTM) characterisation between March 1, 2010, and Aug 31, 2010. Only patients whose baseline clinical, radiological, and, if biopsy was taken, pathological data were undertaken at the host institution were included. Seven MDTMs, consisting of at least one clinician, radiologist, and pathologist, from seven countries (Denmark, France, Italy, Japan, Netherlands, Portugal, and the UK) evaluated cases of diffuse parenchymal lung disease in a two-stage process between Jan 1, and Oct 15, 2015. First, the clinician, radiologist, and pathologist (if lung biopsy was completed) independently evaluated each case, selected up to five differential diagnoses from a choice of diffuse lung diseases, and chose likelihoods (censored at 5% and summing to 100% in each case) for each of their differential diagnoses, without inter-disciplinary consultation. Second, these specialists convened at an MDTM and reviewed all data, selected up to five differential diagnoses, and chose diagnosis likelihoods. We compared inter-observer and inter-MDTM agreements on patient first-choice diagnoses using Cohen's kappa coefficient (κ). We then estimated inter-observer and inter-MDTM agreement on the probability of diagnosis using weighted kappa coefficient (κw). We compared inter-observer and inter-MDTM confidence of patient first-choice diagnosis. Finally, we evaluated the prognostic significance of a first-choice diagnosis of idiopathic pulmonary fibrosis (IPF) versus not IPF for MDTMs, clinicians, and radiologists, using univariate Cox regression analysis.FINDINGS: 70 patients were included in the final study cohort. Clinicians, radiologists, pathologists, and the MDTMs assigned their patient diagnoses between Jan 1, and Oct 15, 2015. IPF made up 88 (18%) of all 490 MDTM first-choice diagnoses. Inter-MDTM agreement for first-choice diagnoses overall was moderate (κ=0·50). Inter-MDTM agreement on diagnostic likelihoods was good for IPF (κw=0·71 [IQR 0·64-0·77]) and connective tissue disease-related interstitial lung disease (κw=0·73 [0·68-0·78]); moderate for non-specific interstitial pneumonia (NSIP; κw=0·42 [0·37-0·49]); and fair for hypersensitivity pneumonitis (κw=0·29 [0·24-0·40]). High-confidence diagnoses (>65% likelihood) of IPF were given in 68 (77%) of 88 cases by MDTMs, 62 (65%) of 96 cases by clinicians, and in 57 (66%) of 86 cases by radiologists. Greater prognostic separation was shown for an MDTM diagnosis of IPF than compared with individual clinician's diagnosis of this disease in five of seven MDTMs, and radiologist's diagnosis of IPF in four of seven MDTMs.INTERPRETATION: Agreement between MDTMs for diagnosis in diffuse lung disease is acceptable and good for a diagnosis of IPF, as validated by the non-significant greater prognostic separation of an IPF diagnosis made by MDTMs than the separation of a diagnosis made by individual clinicians or radiologists. Furthermore, MDTMs made the diagnosis of IPF with higher confidence and more frequently than did clinicians or radiologists. This difference is of particular importance, because accurate and consistent diagnoses of IPF are needed if clinical outcomes are to be optimised. Inter-multidisciplinary team agreement for a diagnosis of hypersensitivity pneumonitis is low, highlighting an urgent need for standardised diagnostic guidelines for this disease.FUNDING: National Institute of Health Research, Imperial College London.

The function of α1 -antitrypsin depends upon the protein folding to a native structure that is only partially stabilised. This renders disease mutants such as the common Z (Glu342Lys) variant vulnerable to misfolding and polymerisation that underlie the disease mechanisms of α1 -antitrypsin deficiency. Combinations of gain- and loss-of-function effects explain the observed disease behaviour. Detailed studies of these processes lead to hypotheses as to why disease variants may arise and persist. They continue to generate and inform novel therapeutic strategies for the treatment of α1 -antitrypsin deficiency, whilst providing insights into other diseases resulting from protein misfolding and abnormal conformational behaviour.

Misfolding, polymerization, and defective secretion of functional alpha-1 antitrypsin underlies the predisposition to severe liver and lung disease in alpha-1 antitrypsin deficiency. We have identified a novel (Ala336Pro, Baghdad) deficiency variant and characterized it relative to the wild-type (M) and Glu342Lys (Z) alleles. The index case is a homozygous individual of consanguineous parentage, with levels of circulating alpha-1 antitrypsin in the moderate deficiency range, but is a biochemical phenotype that could not be classified by standard methods. The majority of the protein was present as functionally inactive polymer, and the remaining monomer was 37% active relative to the wild-type protein. These factors combined indicate an 85 to 95% functional deficiency, similar to that seen with ZZ homozygotes. Biochemical, biophysical, and computational studies further defined the molecular basis of this deficiency. These studies demonstrated that native Ala336Pro alpha-1 antitrypsin could populate the polymerogenic intermediate—and therefore polymerize—more readily than either wild-type alpha-1 antitrypsin or the Z variant. In contrast, folding was far less impaired in Ala336Pro alpha-1 antitrypsin than in the Z variant. The data are consistent with a disparate contribution by the “breach” region and “shutter” region of strand 5A to folding and polymerization mechanisms. Moreover, the findings demonstrate that, in these variants, folding efficiency does not correlate directly with the tendency to polymerize in vitro or in vivo. They therefore differentiate generalized misfolding from polymerization tendencies in missense variants of alpha-1 antitrypsin. Clinically, they further support the need to quantify loss-of-function in alpha-1 antitrypsin deficiency to individualize patient care.

Summary In conformational diseases, native protein conformers convert to pathological intermediates that polymerize. Structural characterization of these key intermediates is challenging. They are unstable and minimally populated in dynamic equilibria that may be perturbed by many analytical techniques. We have characterized a forme fruste deficiency variant of α1-antitrypsin (Lys154Asn) that forms polymers recapitulating the conformer-specific neo-epitope observed in polymers that form in vivo. Lys154Asn α1-antitrypsin populates an intermediate ensemble along the polymerization pathway at physiological temperatures. Nuclear magnetic resonance spectroscopy was used to report the structural and dynamic changes associated with this. Our data highlight an interaction network likely to regulate conformational change and do not support the recent contention that the disease-relevant intermediate is substantially unfolded. Conformational disease intermediates may best be defined using powerful but minimally perturbing techniques, mild disease mutants, and physiological conditions., Highlights ► An α1-antitrypsin deficiency mutant is a forme fruste model for the Z variant ► NMR spectroscopic and ion-mobility mass spectrometric characterization of the mutant ► Residue-specific discrimination of disease-relevant and denaturant-induced ensembles ► A “clasp” motif caps a network of stabilizing interactions in α1-antitrypsin

α1-antitrypsin deficiency is characterised by the misfolding and intracellular polymerisation of mutant α1-antitrypsin within the endoplasmic reticulum of hepatocytes. The retention of mutant protein causes hepatic damage and cirrhosis whilst the lack of an important circulating protease inhibitor predisposes the individuals with severe α1-antitrypsin deficiency to early onset emphysema. Our work over the past 25 years has led to new paradigms for the liver and lung disease associated with α1-antitrypsin deficiency. We review here the molecular pathology of the cirrhosis and emphysema associated with α1-antitrypsin deficiency and show how an understanding of this condition provided the paradigm for a wider group of disorders that we have termed the serpinopathies. The detailed understanding of the pathobiology of α1-antitrypsin deficiency has identified important disease mechanisms to target. As a result, several novel parallel and complementary therapeutic approaches are in development with some now in clinical trials. We provide an overview of these new therapies for the liver and lung disease associated with α1-antitrypsin deficiency.

Alpha1-antitrypsin is a 45-kDa (394-residue) serine protease inhibitor synthesized by hepatocytes, which is released into the circulatory system and protects the lung from the actions of neutrophil elastase via a conformational transition within a dynamic inhibitory mechanism. Relatively common point mutations subvert this transition, causing polymerisation of α1-antitrypsin and deficiency of the circulating protein, predisposing carriers to severe lung and liver disease. We have assigned the backbone resonances of α1-antitrypsin using multidimensional heteronuclear NMR spectroscopy. These assignments provide the starting point for a detailed solution state characterization of the structural properties of this highly dynamic protein via NMR methods. Electronic supplementary material The online version of this article (doi:10.1007/s12104-011-9345-y) contains supplementary material, which is available to authorized users.

The serpinopathies result from the ordered polymerization of mutants of members of the serine proteinase inhibitor (serpin) superfamily. These polymers are retained within the cell of synthesis where they cause a toxic gain of function. The serpinopathies are exemplified by inclusions that form with the common severe Z mutant of α 1 -antitrypsin that are associated with liver cirrhosis. There is considerable controversy as to the pathway of serpin polymerization and the structure of pathogenic polymers that cause disease. We have used synthetic peptides, limited proteolysis, monoclonal antibodies, and ion mobility-mass spectrometry to characterize the polymerogenic intermediate and pathological polymers formed by Z α 1 -antitrypsin. Our data are best explained by a model in which polymers form through a single intermediate and with a reactive center loop-β-sheet A linkage. Our data are not compatible with the recent model in which polymers are linked by a β-hairpin of the reactive center loop and strand 5A. Understanding the structure of the serpin polymer is essential for rational drug design strategies that aim to block polymerization and so treat α 1 -antitrypsin deficiency and the serpinopathies.

Point mutations cause members of the serine protease inhibitor (serpin) superfamily to undergo a novel conformational transition, forming ordered polymers. These polymers characterize a group of diseases termed the serpinopathies. The formation of polymers underlies the retention of α1-antitrypsin within hepatocytes and of neuroserpin within neurons to cause cirrhosis and dementia, respectively. Point mutations of antithrombin, C1 inhibitor, α1-antichymotrypsin, and heparin cofactor II cause a similar conformational transition, resulting in a plasma deficiency that is associated with thrombosis, angioedema, and emphysema. Polymers of serpins can also form in extracellular tissues where they activate inflammatory cascades. This is best described for the Z variant of α1-antitrypsin in which the proinflammatory properties of polymers provide an explanation for both progressive emphysema and the selective advantage of this mutant allele. Therapeutic strategies are now being developed to block the aberrant conformational transitions and so treat the serpinopathies.

Members of the serpin (serine proteinase inhibitor) superfamily play a central role in the control of inflammatory, coagulation, and fibrinolytic cascades. Point mutations that cause abnormal conformational transitions in these proteins can trigger disease. Recent work has defined three pathways by which these conformers cause tissue damage. Here, we describe how these three mechanisms can be integrated into a new model of the pathogenesis of emphysema caused by mutations in the serpin α1-antitrypsin.