A randomized clinical trial of alpha(1)-antitrypsin augmentation therapy

The murine lung as a factory to produce secreted intrapulmonary and circulatory proteins

We have shown that a lentiviral vector (rSIV.F/HN) pseudotyped with the F and HN proteins from Sendai virus generates high levels of intracellular proteins after lung transduction. Here, we evaluate the use of rSIV.F/HN for production of secreted proteins. We assessed whether rSIV.F/HN transduction of the lung generates therapeutically relevant levels of secreted proteins in the lung and systemic circulation using human α1-anti-trypsin (hAAT) and factor VIII (hFVIII) as exemplars. Sedated mice were transduced with rSIV.F/HN carrying either the secreted reporter gene Gaussia luciferase or the hAAT or hFVIII cDNAs by nasal sniffing. rSIV.F/HN-hAAT transduction lead to therapeutically relevant hAAT levels (70 μg/ml) in epithelial lining fluid, with stable expression persisting for at least 19 months from a single application. Secreted proteins produced in the lung were released into the circulation and stable expression was detectable in blood. The levels of hFVIII in murine blood approached therapeutically relevant targets. rSIV.F/HN was also able to produce secreted hAAT and hFVIII in transduced human primary airway cells. rSIV.F/HN transduction of the murine lungs leads to long-lasting and therapeutically relevant levels of secreted proteins in the lung and systemic circulation. These data broaden the use of this vector platform for a large range of disease indications.

Update on α1-antitrypsin deficiency

α₁-Antitrypsin deficiency (AATD) is an inherited metabolic disorder in which mutations in the coding sequence of the SERPINA1 gene prevent secretion of α₁-antitrypsin (α₁-AT) and cause predisposition to pulmonary and liver diseases. The heterogeneity of clinical manifestations in AATD is related to the complexity of biological function of α₁-AT. The role of smoking is crucial in the natural history of lung damage progression in severe AATD individuals, even if it also partly explains the heterogeneity in lung disease. Lung damage progression in AATD can also be related to body mass index, exacerbation rate, sex, environmental exposure and specific mutations of SERPINA1. Recent randomised controlled trials, together with previous observational work, have provided compelling evidence for the importance of early detection and intervention in order to enable patients to receive appropriate treatment and preserve functional lung tissue.

Early detection and intervention in cases of α₁-antitrypsin deficiency are essential to enable appropriate treatment and preserve functional lung tissuehttp://ow.ly/Mr3P30jUEyn

Alpha-1 antitrypsin deficiency: outstanding questions and future directions

Background

Alpha-1 antitrypsin deficiency (AATD) is a rare hereditary condition that leads to decreased circulating alpha-1 antitrypsin (AAT) levels, significantly increasing the risk of serious lung and/or liver disease in children and adults, in which some aspects remain unresolved.

Methods

In this review, we summarise and update current knowledge on alpha-1 antitrypsin deficiency in order to identify and discuss areas of controversy and formulate questions that need further research.

Results

1) AATD is a highly underdiagnosed condition. Over 120,000 European individuals are estimated to have severe AATD and more than 90% of them are underdiagnosed.

Conclusions

2) Several clinical and etiological aspects of the disease are yet to be resolved. New strategies for early detection and biomarkers for patient outcome prediction are needed to reduce morbidity and mortality in these patients; 3) Augmentation therapy is the only specific approved therapy that has shown clinical efficacy in delaying the progression of emphysema. Regrettably, some countries reject registration and reimbursement for this treatment because of the lack of larger randomised, placebo-controlled trials. 4) Alternative strategies are currently being investigated, including the use of gene therapy or induced pluripotent stem cells, and non-augmentation strategies to prevent AAT polymerisation inside hepatocytes.

Alpha-1-Antitrypsin Deficiency: Disease Management and Learning from Studies

Alpha-1-antitrypsin deficiency (AATD) is one of the most frequent genetic causes of liver and lung diseases. Despite its known association with chronic obstructive pulmonary disease (COPD), AATD is largely unrecognised and underdiagnosed. Cases of AATD exist within every COPD or spirometry population but must be actively investigated. AATD is a laboratory diagnosis that must be confirmed by a blood test. A number of clinical 'clues' can raise suspicion of AATD, potentially facilitating earlier diagnosis and initiation of appropriate treatment. Alpha-1-antitrypsin augmentation therapy has a clear role in patients with severe AATD and a FEV₁ ≤65% predicted. Emerging evidence suggests that attenuating the decline in lung density may prolong the time to respiratory failure.

Alpha 1 antitrypsin to treat lung disease in alpha 1 antitrypsin deficiency: recent developments and clinical implications

Alpha 1 antitrypsin deficiency is a hereditary condition characterized by low alpha 1 proteinase inhibitor (also known as alpha 1 antitrypsin [AAT]) serum levels. Reduced levels of AAT allow abnormal degradation of lung tissue, which may ultimately lead to the development of early-onset emphysema. Intravenous infusion of AAT is the only therapeutic option that can be used to maintain levels above the protective threshold. Based on its biochemical efficacy, AAT replacement therapy was approved by the US Food and Drug administration in 1987. However, there remained considerable interest in selecting appropriate outcome measures that could confirm clinical efficacy in a randomized controlled trial setting. Using computed tomography as the primary measure of decline in lung density, the capacity for intravenously administered AAT replacement therapy to slow and modify the course of disease progression was demonstrated for the first time in the Randomized, Placebo-controlled Trial of Augmentation Therapy in Alpha-1 Proteinase Inhibitor Deficiency (RAPID) trial. Following these results, an expert review forum was held at the European Respiratory Society to discuss the findings of the RAPID trial program and how they may change the landscape of alpha 1 antitrypsin emphysema treatment. This review summarizes the results of the RAPID program and the implications for clinical considerations with respect to diagnosis, treatment and management of emphysema due to alpha 1 antitrypsin deficiency.

Randomized, Placebo-Controlled Trials in Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency (AATD) is a condition caused by the inheritance of two mutated SERPINA1 gene alleles. Individuals with AATD are at increased risk of injury to the liver and lungs. The pulmonary manifestations include precocious onset of pulmonary emphysema and bronchiectasis. For nearly three decades, treatment has been available to individuals with emphysema caused by AATD, but this therapy-augmentation of plasma and tissue alpha-1 antitrypsin levels by intravenous administration of human plasma-derived protein-was approved by regulatory authorities based on its biochemical efficacy. This therapy appears to slow the progression of emphysema in patients with AATD. The medical, patient, and regulatory communities have sought assurance that this expensive therapy provides measurable clinical benefit. Documenting such benefit has been difficult because of the slow progression of the underlying lung disease in AATD, the rarity of this genetic condition, and the lack of direct quantitative measurements of emphysema progression. Over the past decade, quantitative computed tomography (CT) densitometry of the lungs has been found to correlate with severity and progression of emphysema. The recent publication of a well-powered, masked, placebo-controlled study using CT densitometry to evaluate the effectiveness of augmentation therapy at slowing the progression of emphysema has provided some assurance of the clinical efficacy of this therapy.

CT densitometry in emphysema: a systematic review of its clinical utility

BACKGROUND

The aim of the study was to assess the relationship between computed tomography (CT) densitometry and routine clinical markers in patients with chronic obstructive pulmonary disease (COPD) and alpha-1 anti-trypsin deficiency (AATD).

METHODS

Multiple databases were searched using a combination of pertinent terms and those articles relating quantitatively measured CT densitometry to clinical outcomes. Studies that used visual scoring only were excluded, as were those measured in expiration only. A thorough review of abstracts and full manuscripts was conducted by 2 reviewers; data extraction and assessment of bias was conducted by 1 reviewer and the 4 reviewers independently assessed for quality. Pooled correlation coefficients were calculated, and heterogeneity was explored.

RESULTS

A total of 112 studies were identified, 82 being suitable for meta-analysis. The most commonly used density threshold was -950 HU, and a significant association between CT density and all included clinical parameters was demonstrated. There was marked heterogeneity between studies secondary to large variety of disease severity within commonly included cohorts and differences in CT acquisition parameters.

CONCLUSION

CT density shows a good relationship to clinically relevant parameters; however, study heterogeneity and lack of longitudinal data mean that it is difficult to compare studies or derive a minimal clinically important difference. We recommend that international consensus is reached to standardize CT conduct and analysis in future COPD and AATD studies.

European Respiratory Society statement: diagnosis and treatment of pulmonary disease in α1-antitrypsin deficiency

α1-antitrypsin deficiency (AATD) is the most common hereditary disorder in adults. It is associated with an increased risk of developing pulmonary emphysema and liver disease. The pulmonary emphysema in AATD is strongly linked to smoking, but even a proportion of never-smokers develop progressive lung disease. A large proportion of individuals affected remain undiagnosed and therefore without access to appropriate care and treatment.

The most recent international statement on AATD was published by the American Thoracic Society and the European Respiratory Society in 2003. Since then there has been a continuous development of novel, more accurate and less expensive genetic diagnostic methods. Furthermore, new outcome parameters have been developed and validated for use in clinical trials and a new series of observational and randomised clinical trials have provided more evidence concerning the efficacy and safety of augmentation therapy, the only specific treatment available for the pulmonary disease associated with AATD.

As AATD is a rare disease, it is crucial to organise national and international registries and collect information prospectively about the natural history of the disease. Management of AATD patients must be supervised by national or regional expert centres and inequalities in access to therapies across Europe should be addressed.

Diagnosing alpha-1 antitrypsin deficiency: the first step in precision medicine

Severe alpha-1 antitrypsin (AAT) deficiency is one of the most common serious genetic diseases in adults of European descent. Individuals with AAT deficiency have a greatly increased risk for emphysema and liver disease. Other manifestations include bronchiectasis, necrotizing panniculitis and granulomatosis with polyangiitis. Despite the frequency and potential severity, AAT deficiency remains under-recognized, and there is often a delay in diagnosis. This review will focus on three recent updates that should serve to encourage testing and diagnosis of AAT deficiency: first, the publication of a randomized clinical trial demonstrating the efficacy of intravenous augmentation therapy in slowing the progression of emphysema in AAT deficiency; second, the mounting evidence showing an increased risk of lung disease in heterozygous PI MZ genotype carriers; last, the recent publication of a clinical practice guideline, outlining diagnosis and management. Though it has been recognized for more than fifty years, AAT deficiency exemplifies the modern paradigm of precision medicine, with a diagnostic test that identifies a genetic subtype of a heterogeneous disease, leading to a targeted treatment.

The Role of Computed Tomography for the Evaluation of Lung Disease in Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency (AATD) is characterized by low serum levels of or dysfunctional alpha-1 proteinase inhibitor. In the lung parenchyma, this results in a loss of protection against the activity of serine proteases, particularly neutrophil elastase. The resultant imbalance in protease and antiprotease activity leads to an increased risk for the development of early-onset emphysema and COPD. As in traditional smoke-related COPD, the assessment of the severity and disease progression of lung disease in AATD is conventionally based on lung function; however, pulmonary function tests are unable to discriminate between emphysema and airways disease, the two hallmark pathologic features of COPD. CT imaging has been used as a tool to further characterize lung structure and evaluate therapeutic interventions in AATD-related COPD. Moreover, recent advances in quantitative CT have significantly improved our assessment of the lung architecture, which has provided investigators and clinicians with a more detailed evaluation of the extent and severity of emphysema and airways disease in AATD. In addition, serial CT imaging measures are becoming increasingly important, as they provide a tool to monitor emphysema progression. This review describes the principles of CT technology and the role of CT imaging in assessing pulmonary disease progression in AATD, including the effect of therapeutic interventions.

COPD in individuals with the PiMZ alpha-1 antitrypsin genotype

Since the discovery of severe alpha-1 antitrypsin deficiency as a genetic risk factor for emphysema, there has been ongoing debate over whether individuals with intermediate deficiency with one protease inhibitor Z allele (PiMZ, or MZ) are at some risk for emphysema. This is important, because MZ individuals comprise 2-5% of the general population. In this review we summarise the evidence about the risks of the MZ population to develop emphysema or asthma. We discuss the different study designs that have tried to answer this question. The risk of emphysema is more pronounced in case-control than in population-based studies, perhaps due to inadequate power. Carefully designed family studies show an increased risk of emphysema in MZ smokers. This is supported by the rapid decline in lung function of MZ individuals when compared to the general population after massive environmental exposures. The risk of asthma in MZ subjects is less studied, and more literature is needed before firm conclusions can be made. Augmentation therapy in MZ individuals is not supported by any objective studies. MZ smokers are at increased risk for emphysema that is more pronounced when other environmental challenges are present.

Alpha-1 antitrypsin augmentation therapy decreases miR-199a-5p, miR-598 and miR-320a expression in monocytes via inhibition of NFκB

Alpha-1 antitrypsin (AAT) augmentation therapy involves infusion of plasma-purified AAT to AAT deficient individuals. Whether treatment affects microRNA expression has not been investigated. This study's objectives were to evaluate the effect of AAT augmentation therapy on altered miRNA expression in monocytes and investigate the mechanism. Monocytes were isolated from non-AAT deficient (MM) and AAT deficient (ZZ) individuals, and ZZs receiving AAT. mRNA (qRT-PCR, microarray), miRNA (miRNA profiling, qRT-PCR), and protein (western blotting) analyses were performed. Twenty one miRNAs were differentially expressed 3-fold between ZZs and MMs. miRNA validation studies demonstrated that in ZZ monocytes receiving AAT levels of miR-199a-5p, miR-598 and miR-320a, which are predicted to be regulated by NFκB, were restored to levels similar to MMs. Validated targets co-regulated by these miRNAs were reciprocally increased in ZZs receiving AAT in vivo and in vitro. Expression of these miRNAs could be increased in ZZ monocytes treated ex vivo with an NFκB agonist and decreased by NFκB inhibition. p50 and p65 mRNA and protein were significantly lower in ZZs receiving AAT than untreated ZZs. AAT augmentation therapy inhibits NFκB and decreases miR-199a-5p, miR-598 and miR-320a in ZZ monocytes. These NFκB-inhibitory properties may contribute to the anti-inflammatory effects of AAT augmentation therapy.

Lung densitometry: why, how and when

Lung densitometry assesses with computed tomography (CT) the X-ray attenuation of the pulmonary tissue which reflects both the degree of inflation and the structural lung abnormalities implying decreased attenuation, as in emphysema and cystic diseases, or increased attenuation, as in fibrosis. Five reasons justify replacement with lung densitometry of semi-quantitative visual scales used to measure extent and severity of diffuse lung diseases: (I) improved reproducibility; (II) complete vs. discrete assessment of the lung tissue; (III) shorter computation times; (IV) better correlation with pathology quantification of pulmonary emphysema; (V) better or equal correlation with pulmonary function tests (PFT). Commercially and open platform software are available for lung densitometry. It requires attention to technical and methodological issues including CT scanner calibration, radiation dose, and selection of thickness and filter to be applied to sections reconstructed from whole-lung CT acquisition. Critical is also the lung volume reached by the subject at scanning that can be measured in post-processing and represent valuable information per se. The measurements of lung density include mean and standard deviation, relative area (RA) at -970, -960 or -950 Hounsfield units (HU) and 1st and 15th percentile for emphysema in inspiratory scans, and RA at -856 HU for air trapping in expiratory scans. Kurtosis and skewness are used for evaluating pulmonary fibrosis in inspiratory scans. The main indication for lung densitometry is assessment of emphysema component in the single patient with chronic obstructive pulmonary diseases (COPD). Additional emerging applications include the evaluation of air trapping in COPD patients and in subjects at risk of emphysema and the staging in patients with lymphangioleiomyomatosis (LAM) and with pulmonary fibrosis. It has also been applied to assess prevalence of smoking-related emphysema and to monitor progression of smoking-related emphysema, alpha1 antitrypsin deficiency emphysema, and pulmonary fibrosis. Finally, it is recommended as end-point in pharmacological trials of emphysema and lung fibrosis.

Quantitative disease progression model of α-1 proteinase inhibitor therapy on computed tomography lung density in patients with α-1 antitrypsin deficiency

Aims

Early‐onset emphysema attributed to α‐1 antitrypsin deficiency (AATD) is frequently overlooked and undertreated. RAPID‐RCT/RAPID‐OLE, the largest clinical trials of purified human α‐1 proteinase inhibitor (A₁‐PI; 60 mg kg^–1 week^–1) therapy completed to date, demonstrated for the first time that A₁‐PI is clinically effective in slowing lung tissue loss in AATD. A posthoc pharmacometric analysis was undertaken to further explore dose, exposure and response.

Methods

A disease progression model was constructed, utilizing observed A₁‐PI exposure and lung density decline rates (measured by computed tomography) from RAPID‐RCT/RAPID‐OLE, to predict effects of population variability and higher doses on A₁‐PI exposure and clinical response. Dose–exposure and exposure–response relationships were characterized using nonlinear and linear mixed effects models, respectively. The dose–exposure model predicts summary exposures and not individual concentration kinetics; covariates included baseline serum A₁‐PI, forced expiratory volume in 1 s and body weight. The exposure–response model relates A₁‐PI exposure to lung density decline rate at varying exposure levels.

Results

A dose of 60 mg kg^–1 week^–1 achieved trough serum levels >11 μmol l^–1 (putative ‘protective threshold’) in ≥98% patients. Dose–exposure–response simulations revealed increasing separation between A₁‐PI and placebo in the proportions of patients achieving higher reductions in lung density decline rate; improvements in decline rates ≥0.5 g l^–1 year^–1 occurred more often in patients receiving A₁‐PI: 63 vs. 12%.

Conclusion

Weight‐based A₁‐PI dosing reliably raises serum levels above the 11 μmol l^–1 threshold. However, our exposure–response simulations question whether this is the maximal, clinically effective threshold for A₁‐PI therapy in AATD. The model suggested higher doses of A₁‐PI would yield greater clinical effects.

Small airways disease: time for a revisit?

It is increasingly acknowledged that delays in the diagnosis of chronic inflammatory lung conditions have hampered our understanding of pathogenesis and thus our ability to design efficacious therapies. This is particularly true for COPD, where most patients are diagnosed with moderate-to-severe airflow obstruction and little is known about the inflammatory processes present in early disease. There is great interest in developing screening tests that can identify those most at risk of developing COPD before airflow obstruction has developed for the purpose of research and clinical care. Landmark pathology studies have suggested that damage to the small airways precedes the development of airflow obstruction and emphysema and, thus, presents an opportunity to identify those at risk of COPD. However, despite a number of physiological tests being available to assess small airways function, none have been adopted into routine care in COPD. The reasons that tests of small airways have not been utilized widely include variability in test results and a lack of validated reference ranges from which to compare results for some methodologies. Furthermore, population studies have not consistently demonstrated their ability to diagnose disease. However, the landscape may be changing. As the equipment that delivers tests of small airways become more widely available, reference ranges are emerging and newer methodologies specifically seek to address variability and difficulty in test performance. Moreover, there is evidence that while tests of small airways may not be helpful across the full range of established disease severity, there may be specific groups (particularly those with early disease) where they might be informative. In this review, commonly utilized tests of small airways are critically appraised to highlight why these tests may be important, how they can be used and what knowledge gaps remain for their use in COPD.

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary

This Executive Summary of the Global Strategy for the Diagnosis, Management, and Prevention of COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 report focuses primarily on the revised and novel parts of the document. The most significant changes include: (1) the assessment of chronic obstructive pulmonary disease has been refined to separate the spirometric assessment from symptom evaluation. ABCD groups are now proposed to be derived exclusively from patient symptoms and their history of exacerbations; (2) for each of the groups A to D, escalation strategies for pharmacologic treatments are proposed; (3) the concept of deescalation of therapy is introduced in the treatment assessment scheme; (4) nonpharmacologic therapies are comprehensively presented; and (5) the importance of comorbid conditions in managing chronic obstructive pulmonary disease is reviewed.

Clinical utility of alpha-1 proteinase inhibitor in the management of adult patients with severe alpha-1 antitrypsin deficiency: a review of the current literature

Alpha-1 antitrypsin (AAT) functions primarily to inhibit neutrophil elastase, and its deficiency predisposes individuals to the development of chronic obstructive pulmonary disease (COPD). The putative protective serum concentration is generally considered to be above a threshold of 11 μM/L, and therapeutic augmentation of AAT above this value is believed to retard the progression of emphysema. Several AAT preparations, all derived from human donor plasma, have been commercialized since approval by the US Food and Drug Administration (FDA) in 1987. Biochemical efficacy has been demonstrated by augmentation of pulmonary antiprotease activity, but demonstration of clinical efficacy in randomized, placebo-controlled trials has been hampered by the practical difficulties of performing conventional studies in a rare disease with a relatively long natural history. Computed tomography has been applied to measure lung density as a more specific and sensitive surrogate outcome measure of emphysema than physiologic indices, such as forced expiratory volume in 1 second, and studies consistently show a therapeutic reduction in the rate of lung density decline. However, convincing evidence of benefit using traditional clinical measures remains elusive. Intravenous administration of AAT at a dose of 60 mg/kg/week is the commonest regime in use and has well-documented safety and tolerability. International and national guidelines on the management of AAT deficiency recommend intravenous augmentation therapy to supplement optimized usual COPD treatment in patients with severe deficiency and evidence of lung function impairment.

Long-term clinical outcomes following treatment with alpha 1-proteinase inhibitor for COPD associated with alpha-1 antitrypsin deficiency: a look at the evidence

Alpha-1 antitrypsin deficiency (AATD) is a common hereditary disorder caused by mutations in the SERPINA1 gene, which encodes alpha-1 antitrypsin (AAT; also known as alpha 1-proteinase inhibitor, A₁-PI). An important function of A₁-PI in the lung is to inhibit neutrophil elastase, one of various proteolytic enzymes released by activated neutrophils during inflammation. Absence or deficiency of A₁-PI leads to an imbalance between elastase and anti-elastase activity, which results in progressive, irreversible destruction of lung tissue, and ultimately the development of chronic obstructive pulmonary disease with early-onset emphysema. AATD is under-diagnosed, patients can experience long delays before obtaining an accurate diagnosis, and the consequences of delayed diagnosis or misdiagnosis can be severe. Currently, A₁-PI therapy is the only available treatment that addresses disease etiology in patients with AATD; however, demonstrating clinical efficacy of A₁-PI therapy is challenging. In order to show therapeutic efficacy with traditional endpoints such as forced expiratory volume in one second and mortality, large sample sizes and longer duration trials are required. However, AATD is a rare, slow progressive disease, which can take decades to manifest clinically and recruiting sufficient numbers of patients into prolonged placebo-controlled trials remains a significant obstacle. Despite this, the Randomized, placebo-controlled trial of augmentation therapy in Alpha 1-Proteinase Inhibitor Deficiency (RAPID) and RAPID Extension trial, the largest clinical program completed to date, utilized quantitative chest computed tomography as a sensitive and specific measure of the extent of emphysema. Findings from the RAPID/RAPID Extension program definitively confirmed the benefits of A₁-PI therapy in slowing disease progression and provided evidence of a disease-modifying effect of A₁-PI therapy in patients with AATD. These findings suggest that the early introduction of treatment in patients with severe emphysema-related AATD may delay the time to death, lung transplantation or crippling respiratory complaints. In addition, there is now limited evidence that A₁-PI therapy provides a gain of more than five life-years, supporting previous observations based on registry data. With the clinical efficacy of A₁-PI therapy now demonstrated, further studies are required to assess long-term outcomes.

Treatment of lung disease in alpha-1 antitrypsin deficiency: a systematic review

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) is a rare genetic condition predisposing individuals to chronic obstructive pulmonary disease (COPD). The treatment is generally extrapolated from COPD unrelated to AATD; however, most COPD trials exclude AATD patients; thus, this study sought to systematically review AATD-specific literature to assist evidence-based patient management.

METHODS

Standard review methodology was used with meta-analysis and narrative synthesis (PROSPERO-CRD42015019354). Eligible studies were those of any treatment used in severe AATD. Randomized controlled trials (RCTs) were the primary focus; however, case series and uncontrolled studies were eligible. All studies had ≥10 participants receiving treatment or usual care, with baseline and follow-up data (>3 months). Risk of bias was assessed appropriately according to study methodology.

RESULTS

In all, 7,296 studies were retrieved from searches; 52 trials with 5,632 participants met the inclusion criteria, of which 26 studies involved alpha-1 antitrypsin augmentation and 17 concerned surgical treatments (largely transplantation). Studies were grouped into four management themes: COPD medical, COPD surgical, AATD specific, and other treatments. Computed tomography (CT) density, forced expiratory volume in 1 s, diffusing capacity of the lungs for carbon monoxide, health status, and exacerbation rates were frequently used as outcomes. Meta-analyses were only possible for RCTs of intravenous augmentation, which slowed progression of emphysema measured by CT density change, 0.79 g/L/year versus placebo (P=0.002), and associated with a small increase in exacerbations 0.29/year (P=0.02). Mortality following lung transplant was comparable between AATD- and non-AATD-related COPD. Surgical reduction of lung volume demonstrated inferior outcomes compared with non-AATD-related emphysema.

CONCLUSION

Intravenous augmentation remains the only disease-specific therapy in AATD and there is evidence that this slows decline in emphysema determined by CT density. There is paucity of data around other treatments in AATD. Treatments for usual COPD may not be as efficacious in AATD, and further studies may be required for this disease group.

Lung Mass in Smokers

RATIONALE AND OBJECTIVE

Emphysema is characterized by airspace dilation, inflammation, and irregular deposition of elastin and collagen in the interstitium. Computed tomographic studies have reported that lung mass (LM) may be increased in smokers, a finding attributed to inflammatory and parenchymal remodeling processes observed on histopathology. We sought to examine the epidemiologic and clinical associations of LM in smokers.

MATERIALS AND METHODS

Baseline epidemiologic, clinical, and computed tomography (CT) data (n = 8156) from smokers enrolled into the COPDGene Study were analyzed. LM was calculated from the CT scan. Changes in lung function at 5 years' follow-up were available from 1623 subjects. Regression analysis was performed to assess for associations of LM with forced expiratory volume in 1 second (FEV₁) and FEV₁ decline.

RESULTS

Subjects with Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 chronic obstructive pulmonary disease had greater LM than either smokers with normal lung function or those with GOLD 2-4 chronic obstructive pulmonary disease (P < 0.001 for both comparisons). LM was predictive of the rate of the decline in FEV₁ (decline per 100 g, -4.7 ± 1.7 mL/y, P = 0.006).

CONCLUSIONS

Our cross-sectional data suggest the presence of a biphasic radiological remodeling process in smokers: the presence of such nonlinearity must be accounted for in longitudinal computed tomographic studies. Baseline LM predicts the decline in lung function.

Phenotyping emphysema and airways disease: Clinical value of quantitative radiological techniques

The pathophysiology of chronic obstructive pulmonary disease (COPD) and Alpha one antitrypsin deficiency is increasingly recognised as complex such that lung function alone is insufficient for early detection, clinical categorisation and dictating management. Quantitative imaging techniques can detect disease earlier and more accurately, and provide an objective tool to help phenotype patients into predominant airways disease or emphysema. Computed tomography provides detailed information relating to structural and anatomical changes seen in COPD, and magnetic resonance imaging/nuclear imaging gives functional and regional information with regards to ventilation and perfusion. It is likely imaging will become part of routine clinical practice, and an understanding of the implications of the data is essential. This review discusses technical and clinical aspects of quantitative imaging in obstructive airways disease.

Global Strategy for the Diagnosis, Management and Prevention of Chronic Obstructive Lung Disease 2017 Report: GOLD Executive Summary

This Executive Summary of the Global Strategy for the Diagnosis, Management and Prevention of COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 Report focuses primarily on the revised and novel parts of the document. The most significant changes include: (i) the assessment of chronic obstructive pulmonary disease has been refined to separate the spirometric assessment from symptom evaluation. ABCD groups are now proposed to be derived exclusively from patient symptoms and their history of exacerbations; (ii) for each of the groups A to D, escalation strategies for pharmacological treatments are proposed; (iii) the concept of de-escalation of therapy is introduced in the treatment assessment scheme; (iv)non-pharmacological therapies are comprehensively presented and (v) the importance of co-morbid conditions in managing COPD is reviewed.

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report: GOLD Executive Summary

This Executive Summary of the Global Strategy for the Diagnosis, Management, and Prevention of COPD (GOLD) 2017 Report focuses primarily on the revised and novel parts of the document. The most significant changes include: 1) the assessment of COPD has been refined to separate the spirometric assessment from symptom evaluation. ABCD groups are now proposed to be derived exclusively from patient symptoms and their history of exacerbations; 2) for each of the groups A to D, escalation strategies for pharmacological treatments are proposed; 3) the concept of de-escalation of therapy is introduced in the treatment assessment scheme; 4) nonpharmacologic therapies are comprehensively presented and; 5) the importance of comorbid conditions in managing COPD is reviewed.

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report: GOLD Executive Summary

This Executive Summary of the Global Strategy for the Diagnosis, Management, and Prevention of COPD (GOLD) 2017 Report focuses primarily on the revised and novel parts of the document. The most significant changes include: 1) the assessment of chronic obstructive pulmonary disease has been refined to separate the spirometric assessment from symptom evaluation. ABCD groups are now proposed to be derived exclusively from patient symptoms and their history of exacerbations; 2) for each of the groups A to D, escalation strategies for pharmacological treatments are proposed; 3) the concept of de-escalation of therapy is introduced in the treatment assessment scheme; 4) nonpharmacologic therapies are comprehensively presented and; 5) the importance of comorbid conditions in managing COPD is reviewed.

Therapeutics: Alpha-1 Antitrypsin Augmentation Therapy

Subjects with alpha-1 antitrypsin deficiency who develop pulmonary disease are managed following general treatment guidelines, including disease management interventions. In addition, administration of intravenous infusions of alpha-1 proteinase inhibitor (augmentation therapy) at regular schedules is a specific therapy for individuals with AATD with pulmonary involvement.This chapter summarizes the manufacturing differences of commercially available formulations and the available evidence of the effects of augmentation therapy. Biologically, there is clear evidence of in vivo local antiprotease effects in the lung and systemic immunomodulatory effects. Clinically, there is cumulative evidence of slowing lung function decline and emphysema progression. The optimal dose of augmentation therapy is being revised as well as more individualized assessment of who needs this therapy.

Long-term efficacy and safety of α1 proteinase inhibitor treatment for emphysema caused by severe α1 antitrypsin deficiency: an open-label extension trial (RAPID-OLE)

BACKGROUND

Purified α1 proteinase inhibitor (A1PI) slowed emphysema progression in patients with severe α1 antitrypsin deficiency in a randomised controlled trial (RAPID-RCT), which was followed by an open-label extension trial (RAPID-OLE). The aim was to investigate the prolonged treatment effect of A1PI on the progression of emphysema as assessed by the loss of lung density in relation to RAPID-RCT.

METHODS

Patients who had received either A1PI treatment (Zemaira or Respreeza; early-start group) or placebo (delayed-start group) in the RAPID-RCT trial were included in this 2-year open-label extension trial (RAPID-OLE). Patients from 22 hospitals in 11 countries outside of the USA received 60 mg/kg per week A1PI. The primary endpoint was annual rate of adjusted 15th percentile lung density loss measured using CT in the intention-to-treat population with a mixed-effects regression model. This trial is registered with ClinicalTrials.gov, number NCT00670007.

FINDINGS

Between March 1, 2006, and Oct 13, 2010, 140 patients from RAPID-RCT entered RAPID-OLE: 76 from the early-start group and 64 from the delayed-start group. Between day 1 and month 24 (RAPID-RCT), the rate of lung density loss in RAPID-OLE patients was lower in the early-start group (-1·51 g/L per year [SE 0·25] at total lung capacity [TLC]; -1·55 g/L per year [0·24] at TLC plus functional residual capacity [FRC]; and -1·60 g/L per year [0·26] at FRC) than in the delayed-start group (-2·26 g/L per year [0·27] at TLC; -2·16 g/L per year [0·26] at TLC plus FRC, and -2·05 g/L per year [0·28] at FRC). Between months 24 and 48, the rate of lung density loss was reduced in delayed-start patients (from -2·26 g/L per year to -1·26 g/L per year), but no significant difference was seen in the rate in early-start patients during this time period (-1·51 g/L per year to -1·63 g/L per year), thus in early-start patients the efficacy was sustained to month 48.

INTERPRETATION

RAPID-OLE supports the continued efficacy of A1PI in slowing disease progression during 4 years of treatment. Lost lung density was never recovered, highlighting the importance of early intervention with A1PI treatment.

FUNDING

CSL Behring.

The Effect of Alpha-1 Proteinase Inhibitor on Biomarkers of Elastin Degradation in Alpha-1 Antitrypsin Deficiency: An Analysis of the RAPID/RAPID Extension Trials

The RAPID (NCT00261833; N=180) and RAPID Extension (NCT00670007; N=140) trials demonstrated significantly reduced lung density decline in patients with alpha-1 antitrypsin deficiency (AATD) receiving alpha-1 proteinase inhibitor (A1PI) versus placebo. Desmosine and isodesmosine (DES/IDES) are unique crosslinkers of mature elastin fibers and are utilized as measures of elastin degradation. The aim of this post-hoc study was to determine the effect of A1PI therapy on DES/IDES levels in patients from RAPID/RAPID Extension. Plasma levels of DES/IDES were measured using high-performance liquid chromatography and tandem mass spectrometry. Correlation between changes in DES/IDES levels and computed tomography (CT) lung density decline was assessed. Analysis showed that DES/IDES levels were significantly reduced versus baseline in patients receiving A1PI at all time points, from month 3 through month 48. A significant increase from baseline in DES/IDES was observed with placebo at month 24 (n=54; 0.016; p=0.018). DES/IDES change from baseline was significantly different with A1PI versus placebo at months 3 (-0.021; 95% confidence interval [CI] -0.037, 0.004; p=0.026), 12 (-0.040; 95% CI -0.055, 0.025; p<0.001), and 24 (-0.052; 95% CI -0.070, 0.034; p<0.001). Placebo patients started A1PI therapy at month 24 and showed significant reductions in plasma DES/IDES at months 36 (p<0.001) and 48 (p<0.001). Reduced elastin degradation was associated with slower lung density decline (p=0.005), correlating a chemical index of therapy with an anatomical index by CT. In conclusion, A1PI therapy reduced elastin degradation, including pulmonary elastin, in patients with AATD. These data support using DES/IDES levels as biomarkers to monitor emphysema progression and treatment response.

Recent advances in understanding and treating COPD related to α1-antitrypsin deficiency

INTRODUCTION

Alpha-1-antitrypsin deficiency (AATD) is an orphan disease that predisposes individuals to COPD and liver disease. The following is a comprehensive review of AATD from epidemiology to treatment for physicians who treat COPD or asthma. Areas covered: In this comprehensive review of alpha-1-antitrypsin deficiency, we describe the historical perspective, genetics, epidemiology, clinical presentation and symptoms, screening and diagnosis, and treatments of the condition. Expert commentary: The two most important directions for advancing the understanding of AATD involve improving detection of the condition, especially in asymptomatic patients, and advancing knowledge of treatments directed specifically at AATD-related conditions. With regard to treatment for AATD-related conditions, research must continue to explore the implications and importance of augmentation therapy as well as consider new implementations that may prove more successful taking into consideration not only factors of pulmonary function and liver health, but also product availability and financial viability.

Intravenous alpha-1 antitrypsin augmentation therapy for treating patients with alpha-1 antitrypsin deficiency and lung disease

BACKGROUND

Alpha-1 antitrypsin deficiency is an inherited disorder that can cause chronic obstructive pulmonary disease (COPD). People who smoke are more seriously affected and have a greater risk of dying from the disease. Therefore, the primary treatment is to help people give up smoking. There are now also preparations available that contain alpha-1 antitrypsin, but it is uncertain what their clinical effect is.

OBJECTIVES

To review the benefits and harms of augmentation therapy with intravenous alpha-1 antitrypsin in patients with alpha-1 antitrypsin deficiency and lung disease.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed and ClinicalTrials.gov to 25 March 2016.

SELECTION CRITERIA

We included randomised trials of augmentation therapy with alpha-1 antitrypsin compared with placebo or no treatment.

DATA COLLECTION AND ANALYSIS

The two review authors independently selected trials, extracted outcome data and assessed the risk of bias.

MAIN RESULTS

We included three trials (283 participants in the analyses) that ran for two to three years. All participants were ex- or never-smokers and had genetic variants that carried a high risk of developing COPD. Only one trial reported mortality data (one person of 93 died in the treatment group and three of 87 died in the placebo group). There was no information on harms in the oldest trial. Another trial reported serious adverse events in 10 participants in the treatment group and 18 participants in the placebo group. In the most recent trial, serious adverse events occurred in 28 participants in each group. None of the trials reported mean number of lung infections or hospital admissions. In the two trials that reported exacerbations, there were more exacerbations in the treatment group than in the placebo group, but the results of both trials included the possibility of no difference. Quality of life was similar in the two groups. Forced expiratory volume in one second (FEV₁) deteriorated more in participants in the treatment group than in the placebo group but the confidence interval (CI) included no difference (standardised mean difference -0.19, 95% CI -0.42 to 0.05; P = 0.12). For carbon monoxide diffusion, the difference was -0.11 mmol/minute/kPa (95% CI -0.35 to 0.12; P = 0.34). Lung density measured by computer tomography (CT) scan deteriorated significantly less in the treatment group than in the placebo group (mean difference (MD) 0.86 g/L, 95% CI 0.31 to 1.42; P = 0.002). Several secondary outcomes were unreported in the largest and most recent trial whose authors had numerous financial conflicts of interest.

AUTHORS' CONCLUSIONS

This review update added one new study and 143 new participants, but the conclusions remain unchanged. Due to sparse data, we could not arrive at a conclusion about the impact of augmentation therapy on mortality, exacerbations, lung infections, hospital admission and quality of life, and there was uncertainty about possible harms. Therefore, it is our opinion that augmentation therapy with alpha-1 antitrypsin cannot be recommended.

Individualized lung function trends in alpha-1-antitrypsin deficiency: a need for patience in order to provide patient centered management?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by fixed airflow obstruction and accelerated decline of forced expired volume in 1 second (FEV1). Alpha-1-antitrypsin deficiency is a genetic cause of COPD and associated with more rapid decline in lung function, even in some never smokers (NS) but the potential for individualized assessment to reveal differences when compared to group analyses has rarely been considered.

METHODS

We analyzed decline in post-bronchodilator FEV1 and gas transfer (% predicted) over at least 3 years (mean= 6.11, 95% CI 5.80-6.41) in our unique data set of 482 patients with alpha-1-antitrypsin deficiency (PiZ) to determine individual rates of decline, implications for prognosis, and potential clinical management.

FINDINGS

There was a marked variation in individual rates of FEV1 decline from levels consistent with normal aging (observed in 23.5% of patients with established COPD, 57.5% of those without) to those of rapidly declining COPD. Gas transfer did not decline in 12.8% of NS and 20.7% of ex-smokers with established COPD (33.3% and 25.0%, respectively, for those without COPD). There was no correlation between decline in gas transfer and FEV1 for those with COPD, although a weak relationship existed for those without (r=0.218; P<0.025).

CONCLUSION

These data confirm differing individual rates of lung function decline in alpha-1-antitrypsin deficiency, indicating the importance of comprehensive physiological assessment and a personalized approach to patient management.

Update on alpha-1 antitrypsin deficiency: New therapies

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 25years 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.

α1-Antitrypsin deficiency

α1-Antitrypsin deficiency (A1ATD) is an inherited disorder caused by mutations in SERPINA1, leading to liver and lung disease. It is not a rare disorder but frequently goes underdiagnosed or misdiagnosed as asthma, chronic obstructive pulmonary disease (COPD) or cryptogenic liver disease. The most frequent disease-associated mutations include the S allele and the Z allele of SERPINA1, which lead to the accumulation of misfolded α1-antitrypsin in hepatocytes, endoplasmic reticulum stress, low circulating levels of α1-antitrypsin and liver disease. Currently, there is no cure for severe liver disease and the only management option is liver transplantation when liver failure is life-threatening. A1ATD-associated lung disease predominately occurs in adults and is caused principally by inadequate protease inhibition. Treatment of A1ATD-associated lung disease includes standard therapies that are also used for the treatment of COPD, in addition to the use of augmentation therapy (that is, infusions of human plasma-derived, purified α1-antitrypsin). New therapies that target the misfolded α1-antitrypsin or attempt to correct the underlying genetic mutation are currently under development.

α1-Antitrypsin Deficiency

α1-Antitrypsin deficiency is an autosomal codominant condition that predisposes to emphysema and cirrhosis. The condition is common but grossly under-recognized. Identifying patients' α1-antitrypsin deficiency has important management implications (ie, smoking cessation, genetic and occupational counseling, and specific treatment with the infusion of pooled human plasma α1-antitrypsin). The weight of evidence suggests that augmentation therapy slows the progression of emphysema in individuals with severe α1-antitrypsin deficiency.

Present and future utility of computed tomography scanning in the assessment and management of COPD

Computed tomography (CT) is the modality of choice for imaging the thorax and lung structure. In chronic obstructive pulmonary disease (COPD), it used to recognise the key morphological features of emphysema, bronchial wall thickening and gas trapping. Despite this, its place in the investigation and management of COPD is yet to be determined, and it is not routinely recommended. However, lung CT already has important clinical applications where it can be used to diagnose concomitant pathology and determine which patients with severe emphysema are appropriate for lung volume reduction procedures. Furthermore, novel quantitative analysis techniques permit objective measurements of pulmonary and extrapulmonary manifestations of the disease. These techniques can give important insights into COPD, and help explore the heterogeneity and underlying mechanisms of the condition. In time, it is hoped that these techniques can be used in clinical trials to help develop disease-specific therapy and, ultimately, as a clinical tool in identifying patients who would benefit most from new and existing treatments. This review discusses the current clinical applications for CT imaging in COPD and quantification techniques, and its potential future role in stratifying disease for optimal outcome.

Alpha-1 Antitrypsin Deficiency-Associated Chronic Obstructive Pulmonary Disease: A Family Perspective

Alpha-1 antitrypsin (AAT) deficiency (AATD) is a genetic condition that can lead to the early onset of chronic obstructive pulmonary disease (COPD), a disorder that comprises elements of chronic bronchitis and emphysema. AATD is characterized by reduced levels of the AAT protease inhibitor, leading to unrestricted protease activity in the lung, which promotes destruction of lung tissue. In severe cases, patients with AATD have an increased mortality risk and, potentially, a poor quality of life due to more frequent COPD exacerbations and/or limitations on daily activity. However, the burden of AATD on members of the patient's immediate family who may serve as caregivers has not been described. Because the age range at which most patients are diagnosed with AATD may affect the economic status of an individual and/or of a family, it is likely that a diagnosis of AATD may have negative effects that extend beyond those on the diagnosed person to include immediate family members. Here, we review the literature to investigate the impact of the caregiver role of family members in disease states that affect an age group similar to AATD. Furthermore, we provide a case study showing the effect of AATD on immediate family members.

Disease Modification in Emphysema Related to Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency (AATD) is associated with premature onset of emphysema resulting from low serum A₁-PI levels. The only available pharmacological treatment affecting the underlying cause of AATD is A₁-PI therapy. AATD-related emphysema is considered a good model to study disease-modifying effects of treatment as the causative process has been identified. Disease modification is a sustained improvement in disease state following therapeutic intervention that persists when therapy is discontinued. Appropriate trial design and the use of valid study endpoints are key to illustrating disease modification, particularly in clinical trials of rare diseases where it can be difficult to recruit sufficient numbers of patients. Delayed-start trials are advantageous ethically as all patients ultimately receive active treatment and imaging techniques have proven promising as valid study endpoints. Specifically, computed tomography (CT) measured lung density has been used to monitor emphysema and is considered a more sensitive outcome than pulmonary function tests to monitor disease progression. This review will discuss the importance of clinical endpoints and trial design to determine disease modification and will review the evidence for disease modification in AATD-related emphysema. Until recently, clinical studies have not shown a significant effect of A₁-PI therapy, possibly due to insufficient numbers of patients, short duration of clinical trials and lack of appropriate trial design. A recently completed randomised trial and open-label extension study followed a larger study population for a longer duration and incorporated a delayed-start design. The results demonstrated clinical efficacy of A₁-PI therapy and indicate that treatment is disease-modifying.

Lung clearance index for monitoring early lung disease in alpha-1-antitrypsin deficiency

Patients with alpha-1-antitrypsin deficiency (AATD) and a PI-ZZ genotype are at high risk to develop severe emphysema during adulthood. However, little is known about early stages of emphysema and disease manifestation in other PI-types. Spirometry is commonly used for monitoring although early manifestation of emphysema is suspected within the peripheral airways that are not accessible by forced expiratory manoeuvres. We hypothesized that the Lung Clearance Index (LCI) derived from multiple breath nitrogen-washout (N2-washout) is useful to bridge this diagnostic gap. Patients from age 4 years onward and different PI-types performed N2-washout and spirometry. Results were compared to controls. 193 patients (4-79 years, 75% PI-ZZ) and 33 controls (8-60 years) were included. Mean (SD) LCI in patients was 9.1 (3.1) and 6.3 (0.6) in controls (p ≤ 0.001). 47% of adult patients with other than PI-ZZ genotypes and 39% of all patients with normal spirometry had abnormal LCIs. The LCI measured by N2-washout discriminates between patients with AATD and controls, reflects AATD related lung disease in all stages and appears to identify early peripheral lung changes in younger age than spirometry. We conclude that a normal spirometry does not exclude presence of AATD related lung disease even in genotypes other than PI-ZZ.

Antitrypsin Deficiency Assessment and Programme for Treatment (ADAPT): The United Kingdom Registry

The study of rare diseases is compromised by its rarity. The establishment of national and international registries can overcome many of the problems and be used for many monogenetic conditions with relatively consistent outcomes and thus lead to a consistency of clinical management by centres of excellence. However, in Alpha-1 antitrypsin deficiency (AATD), the outcome is highly variable in terms of the organ(s) most affected and the diversity of disease penetration and progression. This creates the added difficulty of understanding the disease sufficiently to monitor and advise the patients to the standard required and importantly design and deliver clinical trials that address the many facets of the disease. The development of research registries and centres of excellence provides the necessary expertise and data to further the understanding and management of diseases like AATD though with significant cost implications. The ADAPT programme was established in 1996 with extensive core funding to enable patients to be seen from all regions of the United Kingdom as an addition to the National Health Service without appointment time constraints and with the purpose of collecting extensive state of the art demographics. The model has proven to be highly productive providing new insights especially into the lung disease, generating and delivering on clinical trials and importantly establishing active patient groups and participation.

Long-term experience in the treatment of α1-antitrypsin deficiency: 25 years of augmentation therapy

Although it is often under-recognised, α₁-antitrypsin deficiency (AATD) represents one of the most common genetic respiratory disorders worldwide. Since the publication of studies in the late 1980s, which demonstrated that plasma-derived augmentation therapy with intravenous α₁-antitrypsin (AAT) can reverse the biochemical deficiencies in serum and lung fluid that characterise emphysema, augmentation therapy has become the cornerstone of patient management. This article, with a focus on experience gained in clinical practice in Germany, provides an overview of some of the research highlights and clinical experience gained in the use of augmentation therapy for AATD during the past 25 years, and briefly discusses the potential role of AAT augmentation therapy in lung transplant recipients. Additionally, the goals of AAT augmentation therapy will be discussed, namely to delay the progression of emphysema, reduce the frequency of exacerbations and improve health-related quality of life. Beyond pulmonary disease, there is recent growing evidence to indicate that AATD could also play a role in rare disorders such as panniculitis, granulomatosis with polyangiitis and ulcerative colitis.

Overview of long-term experience gained with AAT augmentation therapy for the treatment of AATDhttp://ow.ly/HmJLR