Intermediate alpha1-antitrypsin deficiency and chronic obstructive pulmonary disease in Yugoslavia.

As part of a larger investigation of factors associated with chronic obstructive pulmonary disease among Yugoslavian men, an attempt was made to measure the role played by alpha1-antitrypsin deficiency in the causation of those diseases. Almost 3,000 men from Tuzla, an industrial and mining center in central Bosnia, were screened for alpha1-antitrypsin deficiency. Twenty-six men heterozygous for the Pi MZ phenotype were found in this population. The men with the Pi MZ phenotype were compared with a random sample from the total population. The analysis of the data showed that there is an apparent physiologic impairment associated with Pi Z heterozygosity that produces a shift in the relationships between the different lung volumes without over-all hyperinflation, namely, an increase in residual volume at the expense of vital capacity. However, because of the low prevalence of the Pi Z gene, it does not appear to account for much of the high rate of chronic obstructive pulmonary disease found in this population.     

Abnormal interaction of alpha 1-antitrypsin and leukocyte elastolytic activity in patients with chronic obstructive pulmonary disease.

The interaction of serum alpha 1-antitrypsin with leukocyte elastolytic activity was examined in 71 patients with chronic obstructive pulmonary disease and 46 normal subjects. Residual elastolytic activity was present despite adequate amounts of alpha1-antitrypsin in 33 of the 71 patients compared to 6 of the 46 normal control subjects (P less than 0.001). This elastolytic activity was completely abolished by a specific human leukocyte elastase inhibitor. A crossover study designed to detect the source of this abnormal activity revealed that the plasma fraction containing alpha 1-antitrypsin was responsible for inadequate inhibition in 30 of the 39 cases. The residual elastolytic activity from a given patient did not correlate with the serum alpha 1-antitrypsin concentration, alpha 1-antitrypsin phenotype, or history of smoking. Our data suggest that the abnormal interaction of alhpa 1-antitrypsin with leukocyte elastolytic activity is an important additional variable in the gensis of chronic obstructive pulmonary disease.     

Rapid screening for alpha1-antitrypsin deficiency in patients with chronic obstructive pulmonary disease using dried blood specimens

We describe two reliable methods for high-throughput screening of proteinase inhibitor (PI) S and PI Z alpha(1)-antitrypsin (alpha(1)-AT) deficiency alleles from dried blood spot (DBS) specimens using the LightCycler fluorimetric analyzer. The method was used to study 72 patients with chronic obstructive pulmonary disease. Results were confirmed with DNA sequencing. The alpha(1)-AT concentration in DBS was determined with immune nephelometry. Sixteen patients (22%) showed no PI Z or PI S mutations. Five patients (7%) had a heterozygous genotype consisting of a PI S allele and a normal allele for the Z and S positions (non-S non-Z). Twenty-five patients (35%) had a heterozygous genotype consisting of a PI Z and a non-S non-Z allele. Two (3%) had the PI SS genotype, 2 (3%) the PI SZ, and 20 (28%) the PI ZZ. All patients with two normal alpha(1)-AT alleles and 10 heterozygous carriers of one normal and one deficient allele had alpha(1)-AT levels that fell within the alpha(1)-AT DBS normal range (1.8-3.1 mg/dl). Two patients with the rare PI MM(malton)- and PI MM(heerlen)-deficient variants showed deficient alpha(1)-AT levels; PI S and PI Z were not detected. Processing 32 samples requires only 40 minutes. This single-step, cost-effective technology is optimal for working with small amounts of DNA, as are present in DBS. The method is suitable for large-scale screening, in cases where PI type is important.     

Functional assay of alpha 1-antitrypsin in obstructive lung disease

A decreased concentration of alpha 1-antitrypsin is associated with a high risk for obstructive lung disease. We measured the elastase inhibitory capacity, the most important biologic measure of alpha 1-AT function, using a natural substrate. The gel plate assay that we developed uses a commercial gelatin film and is more sensitive, faster, and cheaper than similar elastin-elastase methods. In serum samples from 76 patients with emphysema, there was a high correlation between the immunologically measured alpha 1-AT and the elastase inhibitory capacity. There was no evidence for a functionally deficient alpha 1-AT in any of these patients.     

Risk of hospital admission for obstructive pulmonary disease in alpha(1)-antitrypsin heterozygotes of phenotype PiMZ

Whether subjects heterozygous for alpha(1)-antitrypsin (alpha(1)-AT) deficiency are at risk for development of obstructive pulmonary disease (OPD) has been discussed for the past three decades. Both cohort and case-control studies have reached different conclusions, with the major problems being small sample sizes. A cohort of heterozygotes with the phenotype PiMZ was retrieved from the Danish Alpha(1)-Antitrypsin Deficiency Registry. Ten matched controls for each PiMZ subject were identified from the files of the Danish Central Population Registry. Cases and controls were subsequently linked to the files of the Danish Hospital Discharge Registry, and relative risk for OPD was calculated. In the cohort of 1,551 PiMZ subjects (11,678 person-years), we identified 47 subjects with a discharge diagnosis of OPD, as compared with 206 subjects with this diagnosis in the control group (109,748 person-years), yielding a relative risk (RR) of 2.2 (95% confidence interval [CI]: 1.5 to 3.0). This increased risk was present in both men and women and in all age groups; however, it was significant only in the age group from 40 to 79 yr. Of the 1,551 PiMZ subjects, 565 (36%) were first-degree relatives of PiZ index cases, and it appeared that only this group was at increased risk of hospital admission for OPD (RR: 3.4, 95% CI: 2.2 to 5.3). We conclude that alpha(1)-AT heterozygotes of phenotype PiMZ are at increased risk of hospital admission for OPD if they are first-degree relatives of PiZ index cases only, and that other, yet unknown genetic or environmental factors contribute to the development of lung disease.     

Liver disease associated with alpha1-antitrypsin deficiency

Alpha1-ATD is the most common metabolic liver disease in children for which liver transplantation is performed and, in adults, is associated with cirrhosis, hepatocellular carcinoma, and emphysema. It appears that only a proportion of patients with the deficiency develop clinical manifestations of this disease. Moreover, recent characterization of specific cellular and physiologic events have provided the basis for future potential therapeutic interventions.     

Lung disease associated with alpha1-antitrypsin deficiency

α(1)-Antitrypsin (A1AT) is a polyvalent, acute-phase reactant with an extensive range of biological functions that go beyond those usually linked to its antiprotease (serpin) activities. Genetic mutations cause a systemic deficiency of A1AT, leading to liver and pulmonary diseases, including emphysema and chronic bronchitis. The pathogenesis of emphysema, which involves the destruction of small airway structures and alveolar units, is triggered by cigarette smoke and pollutants. The tissue damage caused by these agents is further potentiated by the mutual interactions between apoptosis, oxidative stress, and protease/antiprotease imbalance. These processes lead to the activation of endogenous mediators of tissue destruction, including the lipid ceramide, extracellular matrix proteins, and abnormal inflammatory cell signaling. In this review, we propose that A1AT has a range of actions that are not restricted to protease inhibition but rather extend to mitigate a range of these pathological processes involved in the development of emphysema. We discuss the evidence indicating that A1AT blocks apoptosis by binding and inhibiting active caspase-3 and modulates a broad range of inflammatory responses induced by neutrophils and by lipopolysaccharide and tumor necrosis factor-α signaling.     

Evidence for excessive bronchial inflammation during an acute exacerbation of chronic obstructive pulmonary disease in patients with alpha(1)-antitrypsin deficiency (PiZ)

Patients with homozygous (PiZ) alpha(1)-antitrypsin (AAT) deficiency have not only low baseline serum AAT levels (approximately 10 to 15% normal) but also an attenuated acute phase response. They are susceptible to the development of premature emphysema but may also be particularly susceptible to lung damage during bacterial exacerbations when there will be a significant neutrophil influx. The purposes of the present study were to assess the inflammatory nature of acute bacterial exacerbations of chronic obstructive pulmonary disease (COPD) in subjects with AAT deficiency, to compare this with COPD patients without deficiency, and to monitor the inflammatory process and its resolution following appropriate antibacterial therapy. At the start of the exacerbation, patients with AAT deficiency had lower sputum AAT (p < 0.001) and secretory leukoprotease inhibitor (SLPI; p = 0.02) with higher elastase activity (p = 0.02) compared with COPD patients without deficiency. Both groups had a comparable acute phase response as assessed by C-reactive protein (CRP) but the AAT-deficient patients had a minimal rise in serum AAT (to < 6 microM). After treatment with antibiotics, in patients with AAT deficiency, there were significant changes in many sputum proteins including a rise in SLPI levels, and a reduction in myeloperoxidase (MPO) and elastase activity (p < 0. 005 for all measures); the sputum chemoattractants interleukin-8 (IL-8) and leukotriene B(4) (LTB(4)) fell (p < 0.01), and protein leak (sputum/serum albumin ratio) became lower (p < 0.01). The changes were rapid and within 3 d of the commencement of antibiotic therapy the biochemical markers had decreased significantly, but took a variable time thereafter to return to baseline values. In conclusion, patients with AAT deficiency had evidence of increased elastase activity at the start of the exacerbation when compared with nondeficient COPD patients which probably reflects a deficient antiproteinase screen (lower sputum AAT and SLPI). The increased bronchial inflammation at presentation resolved rapidly with 14 d of antibiotic therapy.