Alpha 1-antitrypsin deficiency. 3: Clinical manifestations and natural history

Characteristics of alpha-1 antitrypsin deficiency related lung disease exacerbations using a daily symptom diary and urinary biomarkers

BACKGROUND

Pulmonary exacerbations in alpha-1 antitrypsin deficiency (AATD) related lung disease are a significant contributor to disease burden, as with usual COPD. Separating the early stages of an exacerbation from the day-to-day variation in stable COPD is central to the concerns of both clinicians and patients and has been identified as a research priority by NIHR. Clinical tools that distinguish baseline symptoms from those of an exacerbation could allow early and appropriate treatment of AECOPD to reduce the impact and potentially may slow disease progression thereby improving survival and quality of life. Candidate tools include symptom diaries and biomarkers of infection and acute inflammation. Urinary biomarkers of AECOPD have yet to be explored in AATD related COPD.

METHODS

55 patients with AATD related lung disease with a history of 2 or more AECOPD in the preceding year were prospectively followed for 18 months. Each patient recorded symptom scores daily via an electronic symptom diary (eDiary) based on Bronkotest. Urinary biomarkers for AAT, NE, CRP, TIMP1 and desmosine were measured weekly using a home urinary lateral flow device. During self-reported AECOPD patients were asked to perform urine analysis on the first 7 consecutive days.

RESULTS

Type I Anthonisen exacerbations and episodes occurring in autumn/winter lasted longer than Type II/III exacerbations and spring/summer episodes respectively. Median urinary CRP concentration across all study participants increased during Type I AECOPD. eDiary adherence was 68% over a median of 17.8 months (IQR 15.7 to 18.5).

CONCLUSIONS

Use of an eDiary and urinary biomarkers to detect and characterise AECOPD remotely in AATD related lung disease is feasible over a prolonged period and paves the way for precision detection of exacerbations.

Prevalence of Cardiovascular Disease and Rate of Major Adverse Cardiovascular Events in Severe Alpha-1 Antitrypsin Deficiency COPD

Aim

Alpha-1 antitrypsin deficiency is an autosomal co-dominant condition that predisposes individuals to early-onset emphysema. As with COPD, AATD-COPD is associated with pulmonary exacerbations, which impacts on overall mortality and quality of life. Though there is evidence that COPD is associated with a higher prevalence of cardiovascular disease and major adverse cardiovascular events (MACE), it is unclear if this is true for patients with AATD-COPD.

Methods

Prevalence of cardiovascular disease was determined in two separate severe AATD cohorts: AlphaNet, USA and the Birmingham AATD registry, UK. All patients had preexisting lung disease. Cardiovascular disease was defined as presence of any of the following: heart failure, ischaemic heart disease, atrial fibrillation, stroke, and myocardial infarction. A Cox proportional hazards model was used to assess the impact of prior cardiovascular disease and frequent exacerbator phenotype on risk of future MACE.

Results

Out of 3493 patients with severe AATD, 14.7% had prior cardiovascular disease, including stroke (2.3%), myocardial infarction (2.2%), and heart failure (2.5%). Frequent exacerbators were more likely to have preexisting cardiovascular disease compared with those with one or no exacerbations in the preceding year (63% vs 44.8%, p = 0.001). There was increased risk of future MACE in frequent exacerbators (HR 1.85, 95% CI 1.24 to 2.75), former and current smokers (HR 1.80, 95% CI 1.07 to 3.02, p = 0.026, and HR 4.04, 95% CI 1.44 to 11.32, p = 0.008, respectively), and those with prior cardiovascular disease (HR 3.81, 95% CI 2.60 to 5.58, p < 0.001).

Conclusion

In severe AATD-COPD, MACE are associated with an increased exacerbation frequency, previous cardiovascular disease, and a history of smoking.

Tuberculosis and Risk of Emphysema among US Adults in the NHANES I Epidemiologic Follow-Up Study Cohort, 1971-1992

(1) Background: History of TB is a known risk factor for long-term respiratory impairment affecting lung functions in both restrictive and obstructive lung disease. (2) Methods: We analyzed data from the NHANES I Epidemiologic Follow-up Study (NHEFS), a longitudinal study conducted on a noninstitutionalized adult US population aged 25-74 years. Approximately 93 percent of the original NHANES I cohort was successfully traced by the end of the survey period and was available for analysis. The final adjusted model included age groups, gender, family income, lifetime smoking, body mass index (BMI), and frequency of alcohol consumption as potential confounders. (3) Results: The estimated hazards ratio of developing emphysema during follow-up for individuals with a past diagnosis of TB was 54% lower (95% CI = 0.35, 0.61) that that in individuals with no past TB, after controlling for potential confounders and using proportional hazards regression appropriate to the complex sample design. The association, however, was not statistically significant (HR = 0.86, p-value = 0.38) when only a self-reported history of TB was considered as the exposure in an unadjusted model. (4) Conclusions: Tuberculosis (self-reported or LTBI) was strongly (but inversely) associated with emphysema incidence. The association was not statistically significant with only a self-reported history of TB as exposure.

Cardiovascular Risk Associated with Alpha-1 Antitrypsin Deficiency (AATD) Genotypes: A Meta-Analysis with Meta-Regressions

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) can result in severe liver and respiratory disorders. The uninhibited elastase activity on the elastic tissue of arterial walls suggests that AATD may also impact vascular health. Thus, we performed a meta-analysis of the studies evaluating cardiovascular risk in individuals with AATD and non-AATD controls.

METHODS

A systematic literature search was conducted in the main scientific databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Differences between cases and controls were expressed as odds ratios (OR) with 95% confidence intervals (95%CI). The protocol was registered on PROSPERO under the identification number CRD42023429756.

RESULTS

The analysis of eight studies showed that, with a prevented fraction of disease of 15.0% and a corresponding OR of 0.779 (95%CI: 0.665-0.912; p = 0.002), a total of 24,428 individuals with AATD exhibited a significantly lower risk of ischemic heart disease compared to 534,654 non-AATD controls. Accordingly, given a prevented fraction of disease of 19.5%, a lower risk of acute myocardial infarction was documented when analyzing four studies on 21,741 cases and 513,733 controls (OR: 0.774; 95%CI: 0.599-0.999; p = 0.049). Sensitivity and subgroup analyses substantially confirmed results. Meta-regression models suggested that these findings were not influenced by AATD genotypes or prevalence of chronic obstructive pulmonary disease (COPD) among cases and controls, while higher differences in the prevalence of male sex (Z-score: 3.40; p < 0.001), hypertension (Z-score: 2.31; p = 0.021), and diabetes (Z-score: 4.25; p < 0.001) were associated with a lower effect size.

CONCLUSIONS

Individuals with AATD may exhibit a reduced risk of ischemic heart disease, even in the presence of mild deficiency of the serine protease inhibitor. Although caution is warranted due to the observational nature of the data, future pharmacological and rehabilitation strategies should also take this controversial relationship into account.

Hidden Comorbidities in Asthma: A Perspective for a Personalized Approach

Bronchial asthma is the most frequent inflammatory non-communicable condition affecting the airways worldwide. It is commonly associated with concomitant conditions, which substantially contribute to its burden, whether they involve the lung or other districts. The present review aims at providing an overview of the recent acquisitions in terms of asthma concomitant systemic conditions, besides the commonly known respiratory comorbidities. The most recent research has highlighted a number of pathobiological interactions between asthma and other organs in the view of a shared immunological background underling different diseases. A bi-univocal relationship between asthma and common conditions, including cardiovascular, metabolic or neurodegenerative diseases, as well as rare disorders such as sickle cell disease, α1-Antitrypsin deficiency and immunologic conditions with hyper-eosinophilia, should be considered and explored, in terms of diagnostic work-up and long-term assessment of asthma patients. The relevance of that acquisition is of utmost importance in the management of asthma patients and paves the way to a new approach in the light of a personalized medicine perspective, besides targeted therapies.

Clinical trials and promising preclinical applications of CRISPR/Cas gene editing

Treatment of genetic disorders by genomic manipulation has been the unreachable goal of researchers for many decades. Although our understanding of the genetic basis of genetic diseases has advanced tremendously in the last few decades, the tools developed for genomic editing were not efficient and practical for their use in the clinical setting until now. The recent advancements in the research of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated protein (Cas) systems offered an easy and efficient way to edit the genome and accelerated the research on their potential use in the treatment of genetic disorders. In this review, we summarize the clinical trials that evaluate the CRISPR/Cas systems for treating different genetic diseases and highlight promising preclinical research on CRISPR/Cas mediated treatment of a great diversity of genetic disorders. Ultimately, we discuss the future of CRISPR/Cas mediated genome editing in genetic diseases.

Liver-directed SERPINA1 gene therapy attenuates progression of spontaneous and tobacco smoke-induced emphysema in α1-antitrypsin null mice

α₁-antitrypsin deficiency is a rare genetic condition that can cause liver and/or lung disease. There is currently no cure for this disorder, although repeated infusions of plasma-purified protein may slow down emphysema progression. Gene therapy in which a single recombinant adeno-associated viral vector (rAAV) administration would lead to sustained protein expression could therefore similarly affect disease progression, and provide the added benefits of reducing treatment burden and thereby improving the patient’s quality of life. The study presented here tests whether treating the Serpina1a-e knockout mouse model of α₁-antitrypsin-deficiency lung disease with gene therapy would have an impact on the disease course, either on spontaneous disease caused by aging or on accelerated disease caused by exposure to cigarette smoke. Liver-directed gene therapy led to dose-dependent levels of biologically active human α₁-antitrypsin protein. Furthermore, decreased lung compliance and increased elastic recoil indicate that treated mice had largely preserved lung tissue elasticity and alveolar wall integrity compared with untreated mice. rAAV-mediated gene augmentation is therefore able to compensate for the loss of function and restore a beneficial lung protease-antiprotease balance. This work constitutes a preclinical study report of a disease-modifying treatment in the Serpina1a-e knockout mouse model using a liver-specific rAAV serotype 8 capsid.

Alpha-1 Asthma Overlap Syndrome: a Clinical Overview

PURPOSE OF REVIEW

Alpha-1 antitrypsin deficiency (AATD) is one of the most common genetic diseases that is associated with severe complications and yet remains underdiagnosed. The pulmonary symptoms of both AATD and asthma include cough, excessive sputum production, dyspnea, and wheezing. These symptoms overlap significantly leading to difficulty distinguishing between these two conditions and suspicion that there may be an overlap syndrome. We aim to discuss the pathophysiology, clinical manifestations, and treatment of both alpha-1 antitrypsin and asthma and how they may overlap.

RECENT FINDINGS

Recent literature suggests that there is an association between asthma and AATD. This association has been hypothesized to be secondary to an imbalance of elastase and anti-elastase leading to a pro-inflammatory state in patients with AATD. This review serves to overview the pathophysiology, clinical manifestations, and treatment of alpha-1 antitrypsin, asthma, and the increasingly recognized intersection of the two, AATD-asthma overlap syndrome.

Alpha1-antitrypsin deficiency and asthma

α1-antitrypsin deficiency (AATD) is a genetically inherited autosomal-codominant disease with a variable clinical spectrum of lung-related diseases. Pulmonary involvement of α1-antitrypsin deficiency may also include emphysema with variable functional and radiological abnormalities, asthma, and bronchiectasis. Asthma and AATD are mutually exclusive disease entities, but the commonality of neutrophil inflammation across the diseases might suggest common underlying mechanisms of effect. The diseases share many clinical and functional features: patients with AATD commonly first present with asthma-like symptoms; functional alterations may be common to both, such as bronchial hyperresponsiveness or fixed obstruction after bronchial remodeling.  It has been recognized that allergy and asthma often coexist with AATD, but the relationship between allergy, asthma and AATD is not clear. Distinguishing AATD from asthma based on presentation and clinical evaluation is not possible. The clinician must assess each of the elements in the context of the whole patient, any patient with difficult-to-manage asthma should be screened for AATD. From the clinician’s point of view, improving diagnosis in this population is fundamental to optimize clinical management. Genetic studies will probably be needed in the future to unequivocally establish the causal link between AATD and asthma.

[MDR tuberculosis, Alpha-1-anti-trypsin Deficiency, Cough in a Geriatric Nurse]

Multidrug-resistant tuberculosis (MDR-TB) is of low proportion in comparison to the total number of TB patients, however, due to the necessity of a complex medication with potentially severe and life threatening adverse reactions, long term sequelae, and unfavorable outcome special attention is essential. We report the case of a 30-year-old geriatric nurse with a history of chronic cough and hereditary alpha-1-anti-trypsin deficiency (AATD), who suffered from MDR-TB and experienced a number of severe adverse reactions.

Alpha-1 Antitrypsin Deficiency and Pulmonary Morbidity in Patients with Primary Immunodeficiency Disease: A Single-Center Experience

Background

Alpha-1 antitrypsin deficiency (AATD) is of importance in the pathogenesis of pulmonary emphysema, chronic obstructive pulmonary diseases (COPD), and bronchiectasis. Various pulmonary disorders are a typical feature of primary immunodeficiency disease (PID). This includes recurrent pulmonary infections, immunodysregulation, and autoinflammatory diseases. As a result, incidence of acute and chronic pulmonary diseases is higher. Interestingly, pulmonary morbidity in PID and AATD share similar features. To study the coexistence of AATD in patients suffering from PID, we performed the underlying investigation.

Methods

We evaluated a study group of 149 patients (n = 149) with PID. In total, serum AAT concentrations were available for 110 patients (n = 110). For the identified patients, we analyzed both clinical associations and interactions.

Results

Among the investigated patients, reduced serum AAT levels were detected in 7 patients. With regard to the genotype, PI∗ZZ was found in 2 patients, whereas PI∗MZ was observed in 5 patients. Independent of the underlying phenotype, obstructive lung diseases were found in 2 patients with PI∗ZZ and 2 patients with PI∗MZ.

Conclusions

In Germany, the estimated percentage for PI∗ZZ and PI∗MZ is 0.01% and 1.9%, respectively. As demonstrated, the ratio in our study group was even higher. We identified seven patients with AATD. Since AATD contributes to pulmonary morbidity in PID patients, systematic underdiagnosis of the coexistence might yield a strong clinical impact. Hence, AAT analysis should be offered to all patients with confirmed PID diagnoses. To strengthen this finding, we suggest the investigation of larger databases.

α-1 Antitrypsin Genotype-Phenotype Discrepancy in a 42-Year-Old Man Who Carries the Null-Allele

BACKGROUND

Alpha-1-antitrypsin (A1AT) deficiency is a hereditary condition caused by mutations in the SERPINA1 gene and associated with lung emphysema and liver disease. Laboratory testing in suspected A1AT deficiency involves quantifying serum A1AT concentration and identification of specific alleles by genotyping and phenotyping. The aim of this report was to present a case of the null allele carrier with consequent genotype/phenotype/concentration discrepancies and potential misclassification of the Z variant in a 42-year-old white man presenting with symptoms of chronic obstructive pulmonary disease (COPD).

METHOD

Serum A1AT concentration was measured using an immunoturbidimetric assay. A1AT phenotype was determined using isoelectric focusing followed with immunofixation (IEF-IF). Genotyping specifically for the S and Z allele was performed by melting curve analysis using real-time PCR and checked by an alternative PCR-RFLP method. Genotype/phenotype ambiguity and discrepancy were amended using gene sequencing.

RESULTS

Laboratory testing revealed highly reduced A1AT concentration (less than 0.30 g/L), mild to moderate deficient genotype (Pi*Z allele: M/Z and Pi*S allele: M/M) and severe deficient Z homozygous phenotype (Pi ZZ). After repeated sampling, the same discordant results were verified by these tests. Further sequencing revealed two clinically relevant and defective variants: rs199422210 (a rare null allele) and rs28929474 (the Z allele).

CONCLUSION

Due to inability of genotyping kit probes to detect null/Z allele combination (which mimics the Pi ZZ phenotype), our patient was misclassified as mild to moderate deficient Pi*MZ heterozygote. In all unclear cases, whole-gene sequencing is highly recommended in order to determine definitive cause of A1AT deficiency.

α1-Antitrypsin deficiency and chronic respiratory disorders

α₁-antitrypsin deficiency (AATD) is a hereditary disorder associated with a risk of developing liver disease and pulmonary emphysema, and other chronic respiratory disorders (mainly asthma and bronchiectasis); Z variant is the commonest deficient variant of AAT. Determining AAT concentration in serum or plasma and identifying allelic variants by phenotyping or genotyping are fundamental in the diagnosis of AATD. Initial evaluation and annual follow-up measurement of lung function, including post-bronchodilator forced expiratory volume in 1 s and gas transfer inform on disease progression. Lung densitometry is the most sensitive measure of emphysema progression, but must not be use in the follow-up of patients in routine clinical practice. The exogenous administration of purified human serum-derived AAT is the only approved specific treatment for AATD in PiZZ. AAT augmentation therapy is not recommended in PiSZ, PiMZ or current smokers of any protein phenotype, or in patients with hepatic disease. Lung volume reduction and endoscopic bronchial valve placement are useful in selected patients, whereas the survival benefit of lung transplant is unclear. There are several new lines of research in AATD to improve the diagnosis and evaluation of the response to therapy and to develop genetic and regenerative therapies and other treatments.

Comparison of the liquid and lyophilized formulations of Prolastin®-C for Alpha1-Antitrypsin deficiency: Biochemical characteristics, pharmacokinetics, safety and neoantigenicity in rabbits

Multiple analytical and preclinical studies were performed to compare the biochemical characteristics, pharmacokinetics (PK), safety and neoantigenicity of a new 5% liquid formulation of Alpha-1 Proteinase Inhibitor (Liquid A1PI, Prolastin®-C Liquid) with the lyophilized version (Lyophilized A1PI, Prolastin®-C). Liquid A1PI and Lyophilized A1PI had similar average mass (~52 kDa), and both forms exhibited glycoform patterns consistent with the known banding pattern of A1PI (dominated by the M6 and M4 bands, including deconvoluted masses). Both Liquid A1PI and Lyophilized A1PI yielded average percent purity values ranging from 96% to 99% and had active content ranging from 53  mg/mL to 59  mg/mL. The PK profile of Liquid A1PI was similar to Lyophilized A1PI. Safety assessments in rabbits showed good tolerability and no test article-related changes in mortality, clinical signs, clinical pathology, body weight, food consumption, or urinalysis parameters. Following immunodepletion of antibodies that recognize Lyophilized A1PI, there were no significant differences in the anti-drug titers among animals immunized with Lyophilized A1PI and Liquid A1PI (p > 0.05), indicating that no antibodies to neoantigens were generated. Liquid A1PI and Lyophilized A1PI have similar profiles with respect to biochemical characteristics, PK, safety and neoantigenicity.

The Genetics of Pneumothorax

A genetic influence on spontaneous pneumothoraces-those occurring without a traumatic or iatrogenic cause-is supported by several lines of evidence: 1) pneumothorax can cluster in families (i.e., familial spontaneous pneumothorax), 2) mutations in the FLCN gene have been found in both familial and sporadic cases, and 3) pneumothorax is a known complication of several genetic syndromes. Herein, we review known genetic contributions to both sporadic and familial pneumothorax. We summarize the pneumothorax-associated genetic syndromes, including Birt-Hogg-Dubé syndrome, Marfan syndrome, vascular (type IV) Ehlers-Danlos syndrome, alpha-1 antitrypsin deficiency, tuberous sclerosis complex/lymphangioleiomyomatosis, Loeys-Dietz syndrome, cystic fibrosis, homocystinuria, and cutis laxa, among others. At times, pneumothorax is their herald manifestation. These syndromes have serious potential extrapulmonary complications (e.g., malignant renal tumors in Birt-Hogg-Dubé syndrome), and surveillance and/or treatment is available for most disorders; thus, establishing a diagnosis is critical. To facilitate this, we provide an algorithm to guide the clinician in discerning which cases of spontaneous pneumothorax may have a genetic or familial contribution, which cases warrant genetic testing, and which cases should prompt an evaluation by a geneticist.

Portuguese consensus document for the management of alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency (AATD) is a genetic autosomal codominant disorder caused by mutations in SERPINA1 gene. It is one of the most prevalent genetic disorders, although it remains underdiagnosed. Whereas at international level there are several areas of consensus on this disorder, in Portugal, inter-hospital heterogeneity in clinical practice and resources available have been adding difficulties in reaching a diagnosis and in making therapeutic decisions in this group of patients. This raised a need to draft a document expressing a national consensus for AATD. To this end, a group of experts in this field was created within the Portuguese Pulmonology Society - Study group on AATD, in order to elaborate the current manuscript. The authors reviewed the existing literature and provide here general guidance and extensive recommendations for the diagnosis and management of AATD that can be adopted by Portuguese clinicians from different areas of Medicine. This article is part of a supplement entitled "Portuguese consensus document for the management of alpha-1-antitrypsin deficiency" which is sponsored by Sociedade Portuguesa de Pneumologia.

Relationship Between Circulating Serpina3g, Matrix Metalloproteinase-9, and Tissue Inhibitor of Metalloproteinase-1 and -2 with Chronic Obstructive Pulmonary Disease Severity

Chronic obstructive pulmonary disease (COPD) is influenced by genetic and environmental factors. A protease-antiprotease imbalance has been suggested as a possible pathogenic mechanism for COPD. Here, we examined the relationship between circulating serpina3g, matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 and -2 (TIMP-1 and -2, respectively) and severity of COPD. We included 150 stable COPD patients and 35 control subjects in the study. The COPD patients were classified into four groups (I, II, III, and IV), according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines based on the severity of symptoms and the exacerbation risk. Plasma serpina3g, MMP-9, and TIMP-1 and -2 concentrations were significantly higher in the all patients than in control subjects. Plasma serpina3g, MMP-9, and TIMP-1 and -2 concentrations were significantly higher in groups III and IV than in groups I and II. A negative correlation between serpina3g, MMP-9, and TIMP-1 and -2 levels and the forced expiratory volume in 1 s (FEV1) was observed. MMP-9 concentration and the MMP-9/TIMP-1 ratio were higher in patients with emphysema than in other phenotypes (both with p < 0.01). The findings of this study suggest that circulating serpina3g, MMP-9, and TIMP-1 and -2 levels may play an important role in airway remodeling in COPD pathogenesis. Disrupted protease-antiprotease imbalance in patients with COPD is related to the presence of airway injury. MMP-9 concentration and the MMP-9/TIMP-1 ratio are the best predictors of emphysema in COPD patients.

Comparing Patients with ZZ Versus SZ Alpha-1 Antitrypsin Deficiency: Findings from AlphaNet's Disease Management Program

Background: The aim of this study was to examine differences in demographic, health, and behavioral characteristics in individuals with ZZ and SZ genotypes of alpha-1 antitrypsin deficiency (AATD) within AlphaNet's Disease Management and Prevention Program (ADMAPP). Methods: Self-reported data from 3535 patients with AATD, including 3031 (85.7%) patients with ZZ, ZNull, and NullNull genotypes (referred to here as ZZ), and 504 (14.3%) with the SZ genotype were analyzed using t-tests, ANOVAs, and Chi-squared tests. Results: The average age of the cohort was 56.3±10.6 years. The majority of respondents were male (51.2%), white (98.2%) and married (65.2%). SZs reported having more frequent exacerbations (p<0.001) and hospitalizations (p=0.012) than ZZs. A higher proportion of SZs than ZZs had been diagnosed with high blood pressure, diabetes, congestive heart failure, and other comorbid conditions. SZs were more likely than ZZs to report "poor" health (p=0.005). Over a third (38.4%) of SZs do not exercise compared to 27.1% of ZZs (p<0.001). A greater proportion of SZs compared to ZZs view themselves as being overweight (p<0.001) or "out of shape" (p=0.001). A higher proportion of SZs than ZZs reported any history of smoking and current smoking (p<0.001). Conclusions: In patients with AATD and lung disease participating in a disease management program, a higher proportion of SZs than ZZs report exacerbations, comorbidities, and overall poor health, as well as unhealthy behaviors such as lack of exercise and current smoking. Future work should consider the extent to which genotype-specific health promotion interventions would be useful.

Therapeutic potential of alpha-1 antitrypsin in human disease

Alpha-1 antitrypsin (AAT), an alpha globulin glycoprotein, is a member of the serine protease inhibitor (serpin) superfamily. The clinical significance of AAT is highlighted by AAT deficiency. Genetic deficiency of AAT can present as several neutrophilic diseases associated with emphysema, liver cirrhosis, panniculitis, and systemic vasculitis. Recently, animal and human studies have shown that AAT can control inflammatory, immunological, and tissue-protective responses. In addition, AAT treatment can prevent overt hyperglycemia, increase insulin secretion, and reduce cytokine-mediated apoptosis of pancreatic β-cells in diabetes. These multifunctional roles of AAT draw attention to the glycoprotein's therapeutic potential for many inflammatory and autoimmune diseases beyond AAT deficiency. As underlying mechanisms, recent studies have suggested the importance of serine protease inhibitory activity of AAT in obesity-associated insulin resistance, chronic obstructive pulmonary disease, and cystic fibrosis. In this review, we explore the multiple functions of AAT, in particular, the anti-inflammatory and serine protease inhibitory functions, and AAT's therapeutic potential in a variety of human diseases through published literature.

Pulmonary 3He Magnetic Resonance Imaging Biomarkers of Regional Airspace Enlargement in Alpha-1 Antitrypsin Deficiency

RATIONALE AND OBJECTIVES

Thoracic x-ray computed tomography (CT) and hyperpolarized ³He magnetic resonance imaging (MRI) provide quantitative measurements of airspace enlargement in patients with emphysema. For patients with panlobular emphysema due to alpha-1 antitrypsin deficiency (AATD), sensitive biomarkers of disease progression and response to therapy have been difficult to develop and exploit, especially those biomarkers that correlate with outcomes like quality of life. Here, our objective was to generate and compare CT and diffusion-weighted inhaled-gas MRI measurements of emphysema including apparent diffusion coefficient (ADC) and MRI-derived mean linear intercept (L_m) in patients with AATD, chronic obstructive pulmonary disease (COPD) ex-smokers, and elderly never-smokers.

MATERIALS AND METHODS

We enrolled patients with AATD (n = 8; 57 ± 7 years), ex-smokers with COPD (n = 8; 77 ± 6 years), and a control group of never-smokers (n = 5; 64 ± 2 years) who underwent thoracic CT, MRI, spirometry, plethysmography, the St. George's Respiratory Questionnaire, and the 6-minute walk test during a single 2-hour visit. MRI-derived ADC, L_m, surface-to-volume ratio, and ventilation defect percent were generated for the apical, basal, and whole lung as was CT lung area ≤-950 Hounsfield units (RA₉₅₀), low attenuating clusters, and airway count.

RESULTS

In patients with AATD, there was a significantly different MRI-derived ADC (P = .03), L_m (P < .0001), and surface-to-volume ratio (P < .0001), but not diffusing capacity of carbon monoxide, residual volume or total lung capacity, or CT RA₉₅₀ (P > .05) compared to COPD ex-smokers with a significantly different St. George's Respiratory Questionnaire.

CONCLUSIONS

In this proof-of-concept demonstration, we evaluated CT and MRI lung emphysema measurements and observed significantly worse MRI biomarkers of emphysema in patients with AATD compared to patients with COPD, although CT RA₉₅₀ and diffusing capacity of carbon monoxide were not significantly different, underscoring the sensitivity of MRI measurements of AATD emphysema.

The prevalence of PI*S and PI*Z SERPINA1 alleles in healthy individuals and COPD patients in Saudi Arabia: A case-control study

Alpha-1 antitrypsin (AAT) is an acute phase protein produced in hepatocytes. Its deficiency affects the lungs and liver. A case-control study was carried out to determine the prevalence of 2 common deficiency alleles, PI*S and PI*Z, for alpha-1 antitrypsin deficiency (AATD) in both healthy and chronic obstructive pulmmonary disease (COPD)-affected Saudi populations and to clarify the importance of genetic tests in the screening of people at risk for COPD.One thousand blood samples from healthy individuals and 1000 from COPD-affected Saudi individuals were genotyped for the above-mentioned alleles, using real-time polymerase chain reaction (PCR), with the exclusion of any other nationalities. Data were analyzed by determining the allele and genotype frequencies through gene counting and its confidence intervals. The allele frequencies, derived by the Hardy-Weinberg equilibrium method, were analyzed by Pearson Chi-squared tests. The confidence intervals for genotype frequencies were calculated using exploratory software for confidence intervals.Of the 1000 COPD patients included in our study, the prevalence of PI*S and PI*Z was 21.8% and 7.7%, respectively, while within the 1000 normal samples, these alleles occurred in 8.9% of patients for PI*S and 1.6% for PI*Z. The AAT deficiency genotype frequencies (PI*ZZ, PI*SS, and PI*SZ) were 6.5 per 1000 and 87 per 1000 for normal and COPD-affected Saudi individuals.Our results indicated a high prevalence of AATD alleles in the normal Saudi population and an association between AAT deficiency and pulmonary disease development. Additionally, our research confirms the importance of genetic screening to achieve early and accurate diagnosis of AATD.

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.

Alpha-1-antitrypsin deficiency: Genetic variations, clinical manifestations and therapeutic interventions

Alpha-1-antitrypsin (AAT) is an acute phase secretory glycoprotein that inhibits neutrophil proteases like elastase and is considered as the archetype of a family of structurally related serine-protease inhibitors termed serpins. Serum AAT predominantly originates from liver and increases three to five fold during host response to tissue injury and inflammation. The AAT deficiency is unique among the protein-misfolding diseases in that it causes target organ injury by both loss-of-function and gain-of-toxic function mechanisms. Lack of its antiprotease activity is associated with premature development of pulmonary emphysema and loss-of-function due to accumulation of resultant aggregates in chronic obstructive pulmonary disease (COPD). This' in turn' markedly reduces the amount of AAT that is available to protect lungs against proteolytic attack by the enzyme neutrophil elastase. The coalescence of AAT deficiency, its reduced efficacy, and cigarette smoking or poor ventilation conditions have devastating effect on lung function. On the other hand, the accumulation of retained mutant proteins in the endoplasmic reticulum of hepatocytes in a polymerized form rather than secreted into the blood in its monomeric form is associated with chronic liver disease and predisposition to hepatocellular carcinoma (HCC) by gain- of- toxic function. Liver injury resulting from this gain-of-toxic function mechanism in which mutant AAT retained in the ER initiates a series of pathologic events, eventually culminating at liver cirrhosis and HCC. Here in this review, we underline the structural, genetic, polymorphic, biochemical and pathological advances made in the field of AAT deficiency and further comprehensively emphasize on the therapeutic interventions available for the patient.

The Allergist's Role in Detection of Severe Alpha-1 Antitrypsin Deficiency

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) frequently presents as difficult to manage asthma or asthma with fixed obstruction and is well documented as being underdiagnosed in the population.

OBJECTIVE

This study aimed to better describe allergists'/immunologists' involvement in the care of patients with AATD and whether they currently contribute to the underdiagnosis by lack of screening for the condition.

METHODS

Using the Research Electronic Data Capture tool, we submitted a questionnaire to 500 patients with severe AATD (ZZ, SZ, ZNull, and FZ) through the Alpha-1 Foundation Research Registry to collect information about patient diagnosis and treatment patterns. Approximately 45% completed the questionnaire, leading to a final enrollment of 226 participants.

RESULTS

Seventy-eight participants (34%) had seen an allergist, but only 11 (5%) were diagnosed with AATD by their allergist. Likewise, allergists prescribed alpha-1 augmentation therapy to only 5 (8%) of the 59 patients on augmentation therapy. Nearly 46% (n = 104) of all participants were diagnosed with either asthma (28%) or allergic disease (18%) before receiving a diagnosis of AATD. Eighteen patients had been treated with immunotherapy before their diagnosis of AATD, with 94% of these participants receiving treatment for 3 years or longer.

CONCLUSIONS

Our data suggest that specialists in Allergy and Immunology should consider and screen for AATD in patients with asthma in whom spirometry does not return to normal. Furthermore, we propose allergists/immunologists are well suited to screen and treat patients with AATD.

Benefits Among Patients with Alpha-1 Antitrypsin Deficiency Enrolled in a Disease Management and Prevention Program

Rationale: Alpha-1 antitrypsin deficiency (AATD) is characterized by decreased circulating levels or activity of the serum protein, alpha-1 antitrypsin, which increases risk for chronic lung or liver injury and may lead to diseases such as chronic obstructive pulmonary disease (COPD). Currently there is no cure for AATD, and it is largely controlled through disease management and augmentation therapy. This study was designed to describe characteristics of patients enrolled in a disease management and prevention program. Methods: Data from questionnaires administered by AlphaNet were obtained on 4747 AATD patients and included demographic information, medical history, lifestyle choices, and adherence to the Alpha-1 Disease Management and Prevention Program (ADMAPP). A total of 1221 participants (25.72%) had missing adherence information and were excluded, leaving a final study population of 3526. Questionnaire answer dates ranged from May 29, 2008 to February 14, 2015. Logistic regression was used to adjust for demographic factors and comorbidities, comparing the populations stratified by adherence to ADMAPP. Results: After adjustment for age, sex, race, Charlson Comorbidity Index, and income level, individuals who self-reported any adherence to ADMAPP were more likely to feel informed about their condition (odds ratio[OR]_adj 4.95, 95% confidence interval[CI][3.24, 7.57]), and be taking preventive measures, such as smoking cessation (OR_adj 0.47, 95% CI [0.31, 0.70]), appropriate immunizations, and self-reported exercise (OR_adj 2.07, 95% CI [1.74, 2.47]). Conclusions: This study suggests that ADMAPP may be a useful tool for informing and improving preventive measures taken by individuals with AATD. Future studies are needed to clarify the observed associations and study additional outcomes.

A Library of Rare α1-Antitrypsin (AAT) Variant Phenotypes to Aid in the Diagnosis of AAT Deficiency

OBJECTIVES

α1-Antitrypsin (AAT) deficiency is a hereditary disorder due to defective production of the serine protease inhibitor, AAT, which can cause lung and liver diseases. Severity of disease depends particularly on the phenotypic representation of AAT variants in the patient.

METHODS

In this study, we present determination of seven common and nine rare variant phenotypes of AAT using pediatric samples collected in Texas Children's Hospital to address the knowledge gap in the identification of rare variants. We tested 16 different AAT variants that had been stored in a -80 °C freezer over the years to add to the reference library of AAT variants. The gold-standard isoelectric focusing electrophoresis method was used for analysis and interpretation of AAT variants. Each variant was inspected visually by comparing multiple bands, unique to phenotypic identity, with a previously identified pattern.

RESULTS

Seven common M, S, and Z variants were identified as M1M1, M2M2, M1M2, MS, SS, SZ, and ZZ. Nine rare variants were identified as FM, FS, FZ, PM, XM, YM, IM, TS, and EP. These were interpreted independently and in a blinded manner by an experienced technologist and two clinical chemists from two different institutions.

CONCLUSIONS

Our results add to the reference library to identify the rare variant phenotypes of AAT protein. This report will guide clinical laboratories for proper assessment of rare variants and in turn contribute to accurate diagnosis and management of AAT 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.

Lung tissue proteomics identifies elevated transglutaminase 2 levels in stable chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterized by irreversible airflow limitation. Cigarette smoking represents the main risk factor, but the specific mechanisms of COPD are not completely understood. Our aim was to identify COPD-specific proteomic changes involved in disease onset and severity. A comparative proteomic analysis of 51 lung tissues from nonsmokers, smokers, smokers with mild to moderate (stage I-II) COPD, severe to very severe COPD (stage III-IV), and patients with α-1-antitrypsin deficiency (AATD) and idiopathic pulmonary fibrosis (IPF) was performed by cysteine-specific two-dimensional difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry. Selected COPD-specific changes were validated by immunoblotting and further by ELISA in 120 induced sputum and plasma samples from nonsmokers, smokers, and patients with COPD (stage I-III). Altogether 82 altered proteins were identified comprising COPD-, AATD-, and IPF-specific, overlapping, and unspecific changes. Cathepsin D (CTSD), dihydropyrimidinase-related protein 2 (DPYSL2), transglutaminase 2 (TGM2), and tripeptidyl-peptidase 1 (TPP1) were validated as COPD-specific. TGM2 was not associated with smoking and correlated with COPD severity in lung tissue. TGM2 levels in sputum and plasma were elevated in patients with COPD (stage II-III) and correlated with lung function. In conclusion, new proteins related to COPD onset and severity could be identified with TGM2 being a novel potential diagnostic and therapeutic target for COPD. Further studies in carefully characterized cohorts are required to validate the identified changes.

The role of iron in pulmonary pathology

Respiratory disease accounts for a large proportion of emergency admissions to hospital and diseaseassociated mortality. Genetic association studies demonstrate a link between iron metabolism and pulmonary disease phenotypes. IREB2 is a gene that produces iron regulatory protein 2 (IRP2), which has a key role in iron homeostasis. This review addresses pathways involved in iron metabolism, particularly focusing on the role of IREB2. In addition to this, environmental factors also influence phenotypic variation in respiratory disease, for example inhaled iron from cigarette smoke is deposited in the lung and causes tissue damage by altering iron homeostasis. The effects of cigarette smoke are detailed in this article, particularly in relation to lung conditions that favour the upper lobes, such as emphysema and lung cancer. Clinical applications of iron homeostasis are also discussed in this review, especially looking at the pathophysiology of chronic obstructive pulmonary disease, lung cancer, pulmonary infections and acute respiratory distress syndrome. Promising new treatments involving iron are also covered.

Deficient and Null Variants of SERPINA1 Are Proteotoxic in a Caenorhabditis elegans Model of α1-Antitrypsin Deficiency

α1-antitrypsin deficiency (ATD) predisposes patients to both loss-of-function (emphysema) and gain-of-function (liver cirrhosis) phenotypes depending on the type of mutation. Although the Z mutation (ATZ) is the most prevalent cause of ATD, >120 mutant alleles have been identified. In general, these mutations are classified as deficient (<20% normal plasma levels) or null (<1% normal levels) alleles. The deficient alleles, like ATZ, misfold in the ER where they accumulate as toxic monomers, oligomers and aggregates. Thus, deficient alleles may predispose to both gain- and loss-of-function phenotypes. Null variants, if translated, typically yield truncated proteins that are efficiently degraded after being transiently retained in the ER. Clinically, null alleles are only associated with the loss-of-function phenotype. We recently developed a C. elegans model of ATD in order to further elucidate the mechanisms of proteotoxicity (gain-of-function phenotype) induced by the aggregation-prone deficient allele, ATZ. The goal of this study was to use this C. elegans model to determine whether different types of deficient and null alleles, which differentially affect polymerization and secretion rates, correlated to any extent with proteotoxicity. Animals expressing the deficient alleles, Mmalton, Siiyama and S (ATS), showed overall toxicity comparable to that observed in patients. Interestingly, Siiyama expressing animals had smaller intracellular inclusions than ATZ yet appeared to have a greater negative effect on animal fitness. Surprisingly, the null mutants, although efficiently degraded, showed a relatively mild gain-of-function proteotoxic phenotype. However, since null variant proteins are degraded differently and do not appear to accumulate, their mechanism of proteotoxicity is likely to be different to that of polymerizing, deficient mutants. Taken together, these studies showed that C. elegans is an inexpensive tool to assess the proteotoxicity of different AT variants using a transgenic approach.

Freezing the Bioactive Conformation to Boost Potency: The Identification of BAY 85-8501, a Selective and Potent Inhibitor of Human Neutrophil Elastase for Pulmonary Diseases

Human neutrophil elastase (HNE) is a key protease for matrix degradation. High HNE activity is observed in inflammatory diseases. Accordingly, HNE is a potential target for the treatment of pulmonary diseases such as chronic obstructive pulmonary disease (COPD), acute lung injury (ALI), acute respiratory distress syndrome (ARDS), bronchiectasis (BE), and pulmonary hypertension (PH). HNE inhibitors should reestablish the protease-anti-protease balance. By means of medicinal chemistry a novel dihydropyrimidinone lead-structure class was identified. Further chemical optimization yielded orally active compounds with favorable pharmacokinetics such as the chemical probe BAY-678. While maintaining outstanding target selectivity, picomolar potency was achieved by locking the bioactive conformation of these inhibitors with a strategically positioned methyl sulfone substituent. An induced-fit binding mode allowed tight interactions with the S2 and S1 pockets of HNE. BAY 85-8501 ((4S)-4-[4-cyano-2-(methylsulfonyl)phenyl]-3,6-dimethyl-2-oxo-1-[3-(trifluoromethyl)phenyl]-1,2,3,4-tetrahydropyrimidine-5-carbonitrile) was shown to be efficacious in a rodent animal model related to ALI. BAY 85-8501 is currently being tested in clinical studies for the treatment of pulmonary diseases.

Suspecting and Testing for Alpha-1 Antitrypsin Deficiency-An Allergist's and/or Immunologist's Perspective

Alpha-1 antitrypsin deficiency (AATD) is a hereditary, monogenic disorder with no unique clinical features. AATD can be difficult to diagnose as patients commonly present with respiratory symptoms often mistaken for other respiratory syndromes such as asthma or smoking-related chronic obstructive pulmonary disease. In addition, symptoms related to AATD may also affect other organs, including the liver, vasculature, and skin. The severity of AATD varies between individuals, and in severe cases, the irreversible lung damage can develop into emphysema. Early diagnosis is critical to enable the implementation of lifestyle changes and therapeutic options that can slow further deterioration of pulmonary tissue. Once AATD is suspected, a range of tests are available (serum alpha-1 proteinase inhibitor [A1-PI] level measurement, phenotyping, genotyping, gene sequencing) for confirming AATD. Currently, intravenous infusion of A1-PI is the only therapy that directly addresses the underlying cause of AATD, and has demonstrated efficacy in a recent randomized, placebo-controlled trial. This review discusses the etiology, testing, and management of AATD from the allergist's and/or immunologist's perspective. It aims to raise awareness of the condition among physicians who care for people with obstructive lung disorders and are therefore likely to see patients with obstructive lung disease that may, in fact, prove to be AATD.

Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency is an inherited disorder that may cause severe lung and liver disease.

Unusually difficult clinical presentation of an infant suffering from congenital Cytomegalovirus (CMV) infection combined with alpha 1-antitrypsin (A1AT) deficiency

Congenital Cytomegalovirus (CMV) infection and alpha 1-antitrypsin (A1AT) deficiency are separately well described entities, but their simultaneous occurrence can pose a special challenge to a clinician, especially dealing with optimal diagnostic as well as therapeutic approach. Congenital CMV infection is the most common vertically transmitted infection in developed countries. In 85–95% of newborns it runs asymptomatic, while in others it is presented with jaundice, petechias, hepatosplenomegaly and central nervous system damage. A1AT deficiency is on the other hand, the most common genetic liver disease in children, and the clinical spectrum varies from the accidentally detected increased levels of transaminases through to the severe infant cholestasis that can progress to cirrhosis. The following case report describes a two-month old male with severe clinical presentation of congenital CMV infection probably exacerbated due to A1AT deficiency comorbidity. The clinical manifestations and unusually difficult clinical signs this infant presented lead to assumption that the additional liver damage exists. Extensive laboratory analyses were performed, including PCR for CMV DNA, A1AT serum concentration, A1AT genotyping, followed and confirmed with phenotyping. Patient was treated parenteral with ganciclovir, what continued with oral valganciclovir and supportive therapy. Intensive and thorough supportive treatment of the infant resulted in satisfactory progress and excellent outcome. Patient was followed-up till the age of 18 months. The presented case provides excellent example about successful overcoming obstacles in differential diagnosis of A1AT in neonates and infants. Medical charts analysis was the methodology used in making this report.

Hepatocellular carcinoma epidemiology

Primary liver cancer (namely hepatocellular carcinoma, HCC) is worldwide the fifth most common cancer in men and the seventh one in women, and it represents the third most frequent cause of cancer death. HCC rates are particularly high in eastern/south-eastern Asia and in Africa, intermediate in Southern Europe, and low in most high-income countries. Persistent infections by HBV or HCV are the main recognized risk factors for HCC. Aflatoxin exposure is also an important risk factor for HCC development in Africa and eastern Asia. In high-income countries heavy alcohol drinking, tobacco smoking, overweight, diabetes, familial/genetic factors, and selected dietary aspects, have a relevant role. Updated geographic patterns and time trends in mortality from HCC in Europe, USA, Japan, and Australia are provided in the present review, together with an overview of relevant etiologic factors for HCC and main measures for the prevention of this neoplasm.

Alpha-1 antitrypsin deficiency: new developments in augmentation and other therapies

Alpha 1 antitrypsin deficiency (AATD) is a rare cause of chronic obstructive pulmonary disease. The lung disease is thought to be caused primarily by a lack of effective protection against the harmful effects of neutrophil elastase due to the low AAT levels in the lung. Patients may also develop liver disease due to polymerisation of AAT within hepatocytes. Consequently there has been much research over the years into AAT augmentation therapy in patients with lung disease, initially intravenously, and more recently in inhaled forms. This review article will discuss the role of augmentation therapy in AATD and the current status of recombinant AAT. The potential for other therapeutic strategies, such as blocking polymer formation, enhancing autophagy, gene therapy and stem cell-based treatment, will also be discussed more briefly.

Challenging identification of a novel PiISF and the rare PiMmaltonZ α1-antitrypsin deficiency variants in two patients

OBJECTIVES

α1-Antitrypsin (AAT) deficiency is associated with an increased risk for lung and liver disease. Identification of AAT deficiency as the underlying cause of these diseases is important in correct patient management.

METHODS

AAT deficiency is commonly diagnosed by demonstrating low concentrations of AAT followed by genotype and/or phenotype testing. However, this algorithm may miss novel AAT phenotypes.

RESULTS

We report two cases of AAT deficiency in two patients: a case of the novel phenotype PiISF, misclassified as PiII by phenotyping, and a case of the rare phenotype PiMmaltonZ misclassified as PiM2Z.

CONCLUSIONS

These cases highlight the importance of understanding the limitations of a commonly used diagnostic algorithm, use of further gene sequencing in applicable cases, and the potential for underdiagnosis of AAT deficiency in patients with chronic obstructive pulmonary disease.

Genome-wide study of percent emphysema on computed tomography in the general population. The Multi-Ethnic Study of Atherosclerosis Lung/SNP Health Association Resource Study

RATIONALE

Pulmonary emphysema overlaps partially with spirometrically defined chronic obstructive pulmonary disease and is heritable, with moderately high familial clustering.

OBJECTIVES

To complete a genome-wide association study (GWAS) for the percentage of emphysema-like lung on computed tomography in the Multi-Ethnic Study of Atherosclerosis (MESA) Lung/SNP Health Association Resource (SHARe) Study, a large, population-based cohort in the United States.

METHODS

We determined percent emphysema and upper-lower lobe ratio in emphysema defined by lung regions less than -950 HU on cardiac scans. Genetic analyses were reported combined across four race/ethnic groups: non-Hispanic white (n = 2,587), African American (n = 2,510), Hispanic (n = 2,113), and Chinese (n = 704) and stratified by race and ethnicity.

MEASUREMENTS AND MAIN RESULTS

Among 7,914 participants, we identified regions at genome-wide significance for percent emphysema in or near SNRPF (rs7957346; P = 2.2 × 10(-8)) and PPT2 (rs10947233; P = 3.2 × 10(-8)), both of which replicated in an additional 6,023 individuals of European ancestry. Both single-nucleotide polymorphisms were previously implicated as genes influencing lung function, and analyses including lung function revealed independent associations for percent emphysema. Among Hispanics, we identified a genetic locus for upper-lower lobe ratio near the α-mannosidase-related gene MAN2B1 (rs10411619; P = 1.1 × 10(-9); minor allele frequency [MAF], 4.4%). Among Chinese, we identified single-nucleotide polymorphisms associated with upper-lower lobe ratio near DHX15 (rs7698250; P = 1.8 × 10(-10); MAF, 2.7%) and MGAT5B (rs7221059; P = 2.7 × 10(-8); MAF, 2.6%), which acts on α-linked mannose. Among African Americans, a locus near a third α-mannosidase-related gene, MAN1C1 (rs12130495; P = 9.9 × 10(-6); MAF, 13.3%) was associated with percent emphysema.

CONCLUSIONS

Our results suggest that some genes previously identified as influencing lung function are independently associated with emphysema rather than lung function, and that genes related to α-mannosidase may influence risk of emphysema.

Relevance of the mouse model as a therapeutic approach for neutrophil proteinase 3-associated human diseases

Proteinase 3 (PR3) is one of the four elastase-related serine proteinases stored in the azurophilic granules of neutrophils. Although it participates in the pro- and anti-inflammatory responses to infection and inflammation it also retains specific functions that make it different from neutrophil elastase in spite of their close structural resemblance. PR3 is involved in the immune response to infection and is the major autoantigen in granulomatosis with polyangiitis (GPA, formerly Wegener disease), an autoimmune systemic vasculitis with granulomas. Thus, PR3 appears to be a relevant therapeutic target in a variety of inflammatory human diseases. Animal models are required for the testing of new drugs that target PR3 specifically but differences between human and rodent neutrophil PR3 expression and substrate specificity have greatly impaired progress in this direction. This may explain that, to date, there is no spontaneous model of vasculitis associated with anti-PR3 antibodies. In this review, we will focus on the structural and functional differences between human and murine PR3, and how these differences may be by-passed in order to develop a relevant animal model.

A patient with the rare alpha-1-antitrypsin variant (Z)bristol in compound heterozygosity with the Z mutation

Alpha-1-antitrypsin (AAT) is a protease inhibitor (PI), deficiency of which is associated with emphysema and liver disease. The most common deficiency alleles are the S (p.Glu288Val) and Z (p.Glu366Lys) alleles. The Z allele predisposes the AAT protein to polymerization with accumulation in hepatocytes leading to liver disease in PIZ individuals. Most AAT variants have a characteristic pattern of isoforms by isoelectric focusing (IEF). A novel AAT variant called PIZbristol (p.Thr109Met) with an unusual pattern on IEF was described in 1997. We report a patient with the PIZZbristol phenotype that has not been previously described. A 43-year-old man was referred by his GP to a respiratory clinic for breathlessness. His AAT concentration was 0.50 g/L (reference range 1.0-2.0 g/L). An unusual pattern on IEF was seen and sequencing revealed the presence of the rare variant Zbristol in combination with the Z mutation. This is the second reported case of Zbristol and the first in combination with the Z mutation. The patient maintained plasma AAT concentrations around 0.50-0.70 g/L which suggested that the Zbristol protein contributed to the low plasma concentration of AAT. The clinical symptoms associated with PIZ are usually attributed to the plasma deficiency, but his only respiratory complaint was that of breathlessness. This suggests that the PIZZbristol phenotype may confer an effect on respiratory function but is not involved in liver disease.

Facilitating the laboratory diagnosis of α1-antitrypsin deficiency

α(1)-Antitrypsin (AAT) deficiency leads to deterioration of the lungs that can be prevented with diagnosis and treatment. Isoelectric focusing (IEF) electrophoresis is the current biochemical gold standard for detecting AAT deficiency variants but involves complex interpretation. Variant AAT samples were collected over a 2-year period. Stability of AAT for phenotype determination was assessed in whole blood, dried blood spots, and dried serum spots. A compendium displaying 13 common and 5 rare AAT phenotypes was created, and a detailed methodology describing how to recognize AAT banding patterns and interpret a rare phenotype accompanied these visual data. AAT was stable for IEF phenotype analysis for at least 1 week in whole blood and for 24 hours on dried serum spots. In conclusion, a reference compendium of known AAT phenotypes was established that can serve as a resource for interpreting AAT phenotypes.

Determination of alpha-1 antitrypsin level in patients with severe asthma

BACKGROUND

This descriptive study aimed to determine the serum level of alpha-1 antitrypsin (AAT) in patients with severe asthma.

MATERIALS AND METHODS

The serum level of AAT was determined in 43 patients with severe asthma. Pulmonary function tests were performed and data were analyzed by SPPS version 19 software.

RESULT

The mean age of patients was 41±13.8 years (range 14 to 78 years). The AAT level was within the normal range (90-200 mg/dl) in 38 patients (88.4%) and less than normal in 2 patients (4.7%).

CONCLUSION

No association was observed between the serum level of AAT and lung function in severe persistent asthmatic patients. The prevalence of AAT deficiency was low in patients with severe persistent asthma. These results must be confirmed by further longitudinal investigations using larger cohort studies.

Production and characterization of a novel human recombinant alpha-1-antitrypsin in PER.C6 cells

Alpha-1-antitrypsin (A1PI) is a proteinase inhibitor of the serpin superfamily and circulates in plasma at about 1-2 g/L. A1PI deficiency in humans often results in organ damage, particularly to the lungs and liver. Current augmentation therapies rely entirely on A1PI isolated from human plasma, thus prompting an evaluation of alternate sources. We have co-expressed recombinant A1PI and α-2,3-sialyltransferase in the human cell line, PER.C6. The requirement for sialyltransferase overexpression in PER.C6 and the essential contribution of sialic acid glycan capping on pdA1PI and recA1PI to prevent rapid A1PI plasma elimination is shown. Using assays to predict high levels of A1PI production and sialylation, stably transfected PER.C6 cells were screened through two rounds of cell cloning to ensure monoclonality. Fed-batch culturing was used to evaluate recA1PI production and cell line characteristics, identifying subclones expressing over 2.5 g/L recA1PI. Cell stability was assessed over 50 generations, verifying subclone stability during continuous culture. Finally, data are presented showing that recA1PI and pdA1PI are equivalent in their ability to block elastase activity in functional cell-based assays and their pharmacokinetic properties. These data show that recombinant human A1PI recovered from PER.C6 cells offers a reliable source of functionally active A1PI for augmentation therapies and, potentially, other diseases.

Reference and interpretive ranges for α(1)-antitrypsin quantitation by phenotype in adult and pediatric populations

Laboratory evaluation of α(1)-antitrypsin (A1AT) deficiency involves measurement of circulating A1AT protein (quantitation) and characterization of A1AT genetic polymorphisms (phenotyping or genotyping). This study compared adult and pediatric A1AT reference ranges in patients with nondeficiency alleles and examined A1AT concentrations in multiple other phenotypes. A1AT phenotype and quantitation were retrospectively collected on adult (n = 21,444) and pediatric (n = 2,469) samples that were submitted for laboratory evaluation of A1AT deficiency. The 95% reference ranges for normal adult and pediatric populations with the M/M phenotype were determined to be 100 to 273 mg/dL (18.4-50.2 μmol/L) and 93 to 251 mg/dL (17.1-46.2 μmol/L), respectively (P < .0001). Decreased concentrations of A1AT correlated with heterozygosity and homozygosity for the S and Z alleles in both the adult and pediatric groups. Other rare alleles, such as I, were also associated with decreased concentrations of A1AT, particularly in the context of a Z allele, and may warrant monitoring for symptoms of deficiency.