Protease Inhibitor Phenotype Research Articles

Pulmonary function in heterozygotes for alpha,-antitrypsin deficiency: a case-control study.

In this paper we present the initial cross-sectional data from a prospective study of lung aging in heterozygotes for alpha 1-antitrypsin deficiency. Using a case-control design, our cases included 37 heterozygotes for alpha 1-antitrypsin deficiency, protease inhibitor phenotypes MZ and MS, selected because they were parents of children with homozygous alpha 1-antitrypsin deficiency identified in a statewide newborn screening program between 1971 and 1974. All of the heterozygotes were less than 40 yr of age. Our control subjects were selected from a random sample of a working population participating in a longitudinal study of lung aging, using a 2:1 match of control subjects to cases, matching age, sex, ethnic origin, and smoking. Using a respiratory symptom questionnaire, spirometry, and the single-breath N2 test, we found no significant difference between heterozygotes and control subjects in terms of respiratory symptoms or pulmonary function data. We conclude that to 40 yr of age, the heterozygous phenotype (Pi MZ and MS) is not a risk factor for impairment of pulmonary function.

The effects of weekly augmentation therapy in patients with PiZZ α1-antitrypsin deficiency

BackgroundThe major concept behind augmentation therapy with human α1-antitrypsin (AAT) is to raise the levels of AAT in patients with protease inhibitor phenotype ZZ (Glu342Lys)-inherited AAT deficiency and to protect lung tissues from proteolysis and progression of emphysema.ObjectiveTo evaluate the short-term effects of augmentation therapy (Prolastin®) on plasma levels of AAT, C-reactive protein, and chemokines/cytokines.Materials and methodsSerum and exhaled breath condensate were collected from individuals with protease inhibitor phenotype ZZ AAT deficiency-related emphysema (n = 12) on the first, third, and seventh day after the infusion of intravenous Prolastin. Concentrations of total and polymeric AAT, interleukin-8 (IL-8), monocyte chemotactic protein-1, IL-6, tumor necrosis factor-α, vascular endothelial growth factor, and C-reactive protein were determined. Blood neutrophils and primary epithelial cells were also exposed to Prolastin (1 mg/mL).ResultsThere were significant fluctuations in serum (but not in exhaled breath condensate) levels of AAT polymers, IL-8, monocyte chemotactic protein-1, IL-6, tumor necrosis factor-α, and vascular endothelial growth factor within a week of augmentation therapy. In general, augmented individuals had higher AAT and lower serum levels of IL-8 than nonaugmented subjects. Prolastin added for 3 hours to neutrophils from protease inhibitor phenotype ZZ individuals in vitro reduced IL-8 release but showed no effect on cytokine/chemokine release from human bronchial epithelial cells.ConclusionWithin a week, augmentation with Prolastin induced fluctuations in serum levels of AAT polymers and cytokine/chemokines but specifically lowered IL-8 levels. It remains to be determined whether these effects are related to the Prolastin preparation per se or to the therapeutic efficacy of augmentation with AAT.

Protease inhibitor phenotypes and serum alpha-1-antitrypsin levels in patients with COPD: a study from Hong Kong.

Many studies have suggested that an imbalance of protease activation and inhibition might result in COPD with emphysema. Levels of alpha-1-antitrypsin (alpha1-AT), the key protease inhibitor, are genetically determined by alleles that present in many phenotypes/subtypes, some of which are associated with deficiency of the protein. We prospectively evaluated the prevalence of the protease inhibitor (Pi) alleles and phenotypes together with the serum alpha1-AT levels in Chinese patients with COPD. The study population comprised 356 patients with COPD. The male-to-female ratio was 4 : 1 with a mean age of 72.4 years (range 44-93 years). Isoelectric focusing was used for Pi phenotyping/subtyping. The frequencies of Pi alleles and phenotypes were compared with the frequencies in 1085 healthy unrelated Chinese control subjects. The serum alpha1-AT levels were measured by the Cobas Fara assay. PiZ was not detected. No significant difference in distribution of PiM phenotypes/subtypes between patients with COPD and healthy controls was observed, except for M1M3 and M2M3. There was also a significant difference in the proportion of variant S and F alleles between the disease group and the control population. The low prevalence of deficiency Pi phenotypes/subtypes suggests a lack of contribution of alpha1-AT deficiency to the pathogenesis of COPD in Chinese patients. The strategy of launching an alpha1-AT deficiency detection program among COPD patients, based on the recommendation of the World Health Organization, may not be readily applicable in our local setting.

Virologic rebound on HAART in the context of low treatment adherence is associated with a low prevalence of antiretroviral drug resistance.

The contributions of viral drug resistance, drug pharmacokinetics, and treatment adherence to failure of protease inhibitor (PI)-based highly active antiretroviral therapy (HAART) have been explored in isolation. We examined the interactions between these factors. Patients on their first PI-based HAART combination for >6 months with plasma HIV viral load (VL) >1000 copies/mL ("viremic" group) were compared with patients with a stable VL <50 copies/mL ("nonviremic" group). Data were collected on adherence (measured electronically), PI plasma levels (sampled randomly, at trough and twice after an observed dose), viral genotype, and phenotype. Mean adherence was significantly lower in the viremic group (84.3% versus 100.1%; p =.005). In the viremic group, substitutions in HIV protease were detected most frequently in the following positions in subjects on indinavir (IDV): L10I/V (35.7%), M46I/L (35.7%), A71T/V (35.7%), V82A (42.9%); and for subjects on nelfinavir (NFV): D30N (50.0%), V77I (56.3%), N88D (37.5%). Phenotypic resistance was detected in 20% of isolates from patients on IDV and 42% on NFV. Lower adherence was associated with detection of fewer resistance substitutions (r = 0.52; p =.005) and less phenotypic resistance (rho = 0.56, p =.005). There were no differences between the groups in pharmacokinetics. However, in viremic subjects, lower postdose NFV levels were associated with higher resistance (rho = -0.61, p =.02).

Exhaled nitric oxide in patients with PiZZ Phenotype-related α 1-anti-trypsin deficiency

There is no report of exhaled NO (eNO) in subjects with different phenotypes ofα1 -anti-trypsin (AAT) deficiency.Exhaled nitric oxide was evaluated by means of single-breath chemiluminescence analysis (fractional exhaled concentration at the plateau level [plFENO]) in 40 patients with AAT deficiency. Patients were divided according to the protease inhibitor (Pi) phenotype: PiMZ/MS, n=25; PiSZ n=6; PiZZ, n=9. Nineteen healthy subjects served as controls. Levels of eNO in PiZZ patients were also compared with those of subjects, without AAT deficiency (PiMM), matched for diagnosis, sex, age, smoking habit and forced expiratory volume in 1 sec (FEV1). In AAT deficiency subjects airway hyper-responsiveness to methacholine (PD20FEV1) was also assessed.plFENOwas significantly lower in the PiZZ group (4·5±1·4 ppb) than in matched PiMM subjects (8·2±3·8 ppb), in healthy controls (9·3±2·8 ppb) and in patients of other phenotypes. Dynamic lung volumes and DLCOwere significantly lower in PiZZ than in other AAT-deficient patients. Bronchial hyper-responsiveness was not different among AAT phenotypes.These results suggest that eNO may be significantly reduced in PiZZ as compared to healthy control subjects and to AAT subjects with other phenotypes, independent of the level of airway obstruction. Whether, at least potentially, eNO may be considered as an early marker of lung involvement in AAT deficiency must be confirmed with studies on larger number of subjects.

Protease inhibitor phenotype BsaskatoonM is not associated with emphysema - a 20-year follow-up study.

To investigate the association between the PiBsaskatoon variant of alpha-1 protease inhibitor (a1 Pi), present in the heterozygous state, and the development of emphysema. Twenty-year follow-up in the third generation of a family with the variant, naturally controlled with regard to both environmental influences and other genetic factors. University teaching hospital. Ten siblings, five with PiBsaskatoonM phenotype and five with PiM phenotype, 33 to 46 years of age. Respiratory symptoms and smoking histories; pulmonary function tests, including static lung volumes, dynamic lung volumes before and after salbutamol 200 mg, and diffusing capacity; allergen prick skin tests; serum a1 Pi level, chest radiographs and high resolution computerized tomography lung scans The two groups of siblings had similar mean ages, smoking histories and prevalence of current mild respiratory symptoms. Pulmonary function data showed normal mean values and no statistically significant differences for all the variables between the two groups. Chest radiographs were normal in all subjects. High resolution computerized tomography scans were normal in eight subjects, and demonstrated mild and very mild centrilobular emphysema in the two subjects with greatest smoking histories (approximately 30 pack-year each); both of these were PiBsaskatoonM phenotype. There is no evidence of an association between a1 Pi phenotype PiBsaskatoonM and the development of emphysema.

Alpha-1-antitrypsin deficiency in aneurysmal disease.

alpha 1-Antitrypsin (alpha 1-AT) deficiency may play a role in arterial aneurysmal disease by allowing increased proteolysis of arterial structural proteins. Alpha 1-AT levels are influenced by variation at the PI (protease inhibitor) locus. PI phenotypes were determined in 173 patients with abdominal aortic aneurysms (77 from Pittsburgh, 96 from London) and in 72 patients with intracranial aneurysms (26 from Pittsburgh, 46 from London). No excess of PI deficiency alleles was observed in either of the aortic aneurysm data sets or in the Pittsburgh intracranial aneurysm data. The PI*Z deficiency allele frequency in the London intracranial aneurysm data was 8-fold higher than in controls; however, this was not significant after correcting for multiple comparisons. PI phenotype had no effect on aneurysm age-at-diagnosis within any of the data sets. Smoking history had an effect on aneurysm age-at-diagnosis only within the Pittsburgh intracranial-aneurysm data.

Bilateral, Recurrent Spontaneous Pneumothorax in a Male Adolescent with Chronic Asthma: A Case for Protease-Antiprotease Imbalance

Recurrent spontaneous pneumothorax rarely occurs in asthma. When an asthmatic patient has recurrent spontaneous pneumothorax, additional predisposing factors need to be considered. We present a case of bilateral, recurrent spontaneous pneumothorax occurring in a male adolescent with chronic atopic asthma. Five episodes occurred during a period of 25 months. He was found to have intermediate alpha- 1-antitrypsin deficiency (protease inhibitor phenotype, PiMS). His father has emphysema and also has the PiMS phenotype. Spontaneous pneumothorax has been reported previously in a 43-year-old man with PiMZ and in a family in which six members had repeated spontaneous pneumothoraces associated with PiM1M2. In addition, another report found elastin and alpha-1-antitrypsin in blebs and bullae from patients with spontaneous pneumothorax. These reported observations and our case report support the notion that protease-antiprotease imbalance is an important factor in the etiology of spontaneous pneumothorax. This is another reason to consider carefully the anti-inflammatory control of the asthmatic process in children and adults with persistent disease.

Low frequency of PIM3 gene in patients with monoclonal gammopathies.

The distribution of PI (protease inhibitor) phenotypes and PI M subtypes was studied in 200 patients with monoclonal gammopathies and 320 healthy blood donors by isoelectric focusing in thin-layer polyacrylamide gels, pH range 4-5. The distribution of PI phenotypes and gene frequencies in the patients differed significantly from the corresponding values found in the blood donors, as shown by the chi 2 test (chi 2 = 16.5, p = 0.02 and chi 2 = 17.6, p = 0.0014, respectively). A lower frequency of the M3 variant was observed in patients, both in homozygous (PI M3) and heterozygous forms (PI M1M3 and PI M2M3). No significant difference between PIz allele frequencies in patients and healthy controls was found.

High resolution computed tomography of the lung in lifelong non-smoking patients with rheumatoid arthritis.

To define pulmonary involvement on high resolution computed tomography (HRCT) of the thorax in lifelong non-smoking rheumatoid arthritis patients and to relate the results to pulmonary function, bronchial reactivity, and a variety of clinical and serological factors. Twenty lifelong non-smoking RA patients (mean age 59 years (range 44-72; 18 females) were studied. Detailed medical and drug histories were taken. Protease inhibitor phenotype (Pi) and HLA-DR4 status were assessed. Schirmer's tear tests were performed to detect keratoconjunctivitis sicca (KCS). Spirometry, flow volume loops, and gas transfer factor measurement were recorded. The degree of bronchial reactivity (PC20 FEV1) was measured by a methacholine inhalation test. Chest and hand radiographs and HRCT of the lung were performed in all patients. Thirteen patients were HLA-DR4 positive. Eighteen had the Pi MM and two the Pi MS phenotype. Eight patients had evidence of KCS on Schirmer's tear testing. Ten patients achieved PC20 FEV1 in the methacholine inhalation test. All the patients had normal chest radiographs and all showed evidence of erosive arthropathy on hand radiographs. Five patients (25%) showed basal bronchiectasis and one mild interstitial lung disease on HRCT. All five patients with bronchiectasis had the Pi MM phenotype, four had HLA-DR4, four had KCS and three achieved PC20 FEV1; these values were not significantly different (p > 0.05) from those in patients without bronchiectasis. Using the highly sensitive technique of HRCT, we found evidence to suggest that the incidence of bronchiectasis in lifelong non-smoking RA patients may be much higher than previously reported.

ASSOCIATION OF HLA-DR4, PROTEASE INHIBITOR PHENOTYPES AND KERATOCONJUNCTIVITIS SICCA WITH PULMONARY ABNORMALITIES IN RHEUMATOID ARTHRITIS

One-hundred rheumatoid arthritis (RA) patients were assessed for the association of HLA-DR4, protease inhibitor (Pi) phenotype and keratoconjunctivitis sicca (KCS) with a variety of clinical features, airflow obstruction and bronchial reactivity. Spirometry, lung volume and gas transfer factor measurements were performed to detect airflow obstruction. Bronchial reactivity to inhaled methacholine was assessed by measuring the provocative dose of methacholine causing a 20% fall in FEV1 from the baseline (PD20). Sixty-two patients were HLA-DR4 positive, 87 had Pi MM and 13 MS phenotypes and 37 had positive Schirmer's tear tests. Patients with KCS had a significantly increased history of wheeze (11/37 vs 7/63, P = 0.03, relative risk (RR) 1.8 [95% CI 1.04, 3.1]), those with HLA-DR4 had a significantly decreased atopy on skin-prick testing [3/62 vs 7/38, were significantly higher in the Pi MS group compared to Pi MM group. There was no significant association of HLA-DR4, Pi phenotype and KCS with bronchial reactivity. We conclude that there is no overall significant association of HLA-DR4, Pi phenotype and KCS with airflow obstruction and bronchial reactivity in RA.

Alpha1-antitrypsin genetic polymorphism in ANCA-positive systemic vasculitis

Alpha 1-antitrypsin (alpha 1-AT) is the major inhibitor of proteinase 3 (PR3), the main target antigen of antineutrophil cytoplasm antibodies (ANCA) in Wegener's granulomatosis. alpha 1-AT is encoded by a polymorphic gene, with over 75 alleles, defining severely, medium and non-deficient protease inhibitor (PI) phenotypes. We describe the association of severely and medium deficient PI phenotypes with anti-PR3 positive systemic vasculitis, and postulate a pathogenetic role for alpha 1-AT deficiency and the occurrence of ANCA, with specificity for PR3 in a subgroup of patients with Wegener's granulomatosis.

Alpha 1-antitrypsin phenotypes in coeliac patients and a control population in the west of Ireland.

alpha 1 antitrypsin or protease inhibitor (Pi) phenotyping was carried out on 111 coeliac disease patients (CD) and 250 controls. The Pi MM phenotype was present in 95 (85.6%) of the coeliacs and 225 (90%) of the controls. The groups did not differ significantly with regard to Pi phenotypes. In the CD group the Pi Phenotype did not relate to HLA B8 or DR3 status. Associated diseases in the CD patients did not correlate with Pi phenotype.

Relation of serum elastin peptide concentration to age, FEV1, smoking habits, alcohol consumption, and protease inhibitor phenotype: an epidemiological study in working men.

In clinical investigations elastin peptide concentration has been proposed as one potential marker of lung elastin degradation. No epidemiological study has yet confirmed this hypothesis. The relation of elastin peptide concentration to some factors closely related to pulmonary emphysema (age, smoking habits, FEV1 alpha protease inhibitor (PI) phenotype) and to alcohol consumption was examined in an epidemiological study of 310 working men. The elastin peptides used for obtaining antibodies and as reference in an ELISA assay were prepared from chemically hydrolysed elastin. The elastin peptide concentration significantly decreased with age from 2.92 (1.54) micrograms/ml among subjects younger than 30 years to 2.18 (1.14) micrograms/ml among subjects older than 50. Elastin peptide concentration did not differ with smoking habits and was clearly unrelated to FEV1. A lower elastin peptide concentration was observed in all groups of subjects with a protease inhibitor phenotype other than PI MM (PI FM, IM, MP, MS, MZ, and S phenotypes). The results cast doubts on the usefulness of the elastin peptide concentration as a marker of lung destruction in middle aged, predominantly healthy men. Blood elastin peptide concentration may reflect both elastin degradation and resynthesis. The results of this analysis suggest that several factors (age, alcohol consumption, non-PI MM phenotype) may be associated with decreased resynthesis of lung elastin. Further studies, conducted in various age groups and including estimates of the degree of lung destruction, are needed to unravel the mechanisms underlying lysis and resynthesis of lung elastin.

An Improved Method for Subtyping Pi in Old Bloodstains

Immunofixation procedures were used for detecting alpha-1 antitrypsin protease inhibitor (Pi) phenotypes in bloodstains. Neuraminidase elution of bloodstains, together with isoelectric focusing, immunofixation, and silver staining techniques, makes possible Pi subtyping in old bloodstains. No extra bands appear when the storage time is no longer than three months.

α1‐antitrypsin deficiency and liver disease: Clinical presentation, diagnosis and treatment

The alpha 1-antitrypsin deficient subject (protease inhibitor (PI) phenotype ZZ) has an increased susceptibility to liver disease. The condition is most commonly identified in early infancy as a conjugated hyperbilirubinaemia with hepatitis (11%) or a bleeding state due to vitamin K malabsorption (2%). 50% of cases have cirrhosis and 25% die in the first decade of life. A further 2% present with cirrhosis in later childhood. Adult males are at risk of hepatoma development with or without cirrhosis. Diagnosis is by isoelectric focussing or allele-specific oligonucleotide hybridization. The treatment is that of cholestasis and cirrhosis including transplantation. The pathobiology of the deficiency state, the mechanism of liver damage and the vulnerability of the newborn liver are discussed in this review. A plea is made for a trial of infusions of alpha 1-antitrypsin in early infancy, as is used safely but without proven efficacy in the emphysematous PIZZ subject. Prospects of therapy by gene modification are also reviewed.

Liver Disease and Heterozygous Alpha‐1‐Antitrypsin Deficiency

From 1985 to 1988 14,938 newborns were screened during the first days of life to determine their protease inhibitor phenotype (Pi) and 467 PiMZ and 456 PiMS were identified. Of these 101 PiMZ and 135 PiMS were followed-up and their clinical, biochemical and, in selected cases, histological data were recorded at two, five and twelve months of age. Nineteen out of 101 PiMZ infants showed hepatic dysfunction at two months, eight at five, and one at twelve months of age, respectively. In 20 of 135 PiMS infants, liver function tests were abnormal at two months, in ten at five and in none at twelve months. It appears that PiMZ and PiMS phenotypes can be associated with hepatic dysfunction during the first six months of life. The marked variability of serum levels of alpha-1-antitrypsin in heterozygotes, make Pi-typing in all cases of neonatal hepatitis advisable. This should also be done for screening purpose.

Association of MS Pi Phenotype with Airway Hyperresponsiveness

Asthmatic families (AFs) and normal families (NFs) were studied to determine the relationship between bronchial hyperresponsiveness and alpha 1-antitrypsin protease inhibitor phenotype. We studied IgE levels, skin test scores, and methacholine sensitivity. In both the AF and NF groups, the subjects with the MS phenotype had significantly greater methacholine-induced bronchial hyperresponsiveness sensitivity than the MM and MZ subjects. These findings suggest that the S allele may be associated with bronchial hyperresponsiveness.

Severe Chemotherapy-Related Hepatic Toxicity Associated with MZ Protease Inhibitor Phenotype

We describe a 10 1/2-month-old boy in whom fulminant hepatic failure following chemotherapy for Wilms' tumor developed. He then received an orthotopic liver transplant. An unexpected finding was the accumulation of alpha 1-antitrypsin (AAT) in periportal hepatocytes. A pretransplant serum sample showed a Pi MZ phenotype. The rarity of hepatic failure following treatment for Wilms' tumor raises the possibility of an increased susceptibility to toxic injury in the presence of AAT accumulation. Determination of the frequency of protease inhibitor MZ phenotype in patients who have chemotherapy-related hepatotoxicity could be used to initiate a prospective study aimed at identifying an at-risk population for chemoradiotherapy-related hepatoxicity.

Alpha-1-Antitrypsin (Protease Inhibitor) Phenotypes and Longevity

We have tested the hypothesis that the protease inhibitor phenotypes MZ and MS are disadvantageous and reduce survival by comparing the prevalence of these phenotypes in a group of 707 very old people (hospital patients) with the prevalences reported in younger populations of blood donors. The MS and MZ phenotypes appear to be no less common among those who have survived to old age, but a highly significant difference was found in the occurrence of the M subtypes. The M1 type was more common in the elderly, and the M heterozygotes were less common than would be predicted from the reported incidence in younger groups and from the Hardy-Weinberg equilibrium. This discrepancy appeared to be smaller in subjects of Mediterranean origin than in those of British or Irish genetic background.