Alpha1-antitrypsin phenotypes in patients with cryptogenic fibrosing alveolitis: a case-control study

Alpha-1 Antitrypsin Levels and Polymorphisms in Interstitial Lung Diseases

BACKGROUND/AIM

Alpha-1 antitrypsin deficiency may be a potential predisposing factor for interstitial lung fibrosis. We investigated alpha-1 antitrypsin levels and its polymorphisms in patients with interstitial lung disease.

MATERIALS AND METHODS

A total of 103 interstitial lung disease patients were compared.

RESULTS

The mean alpha-1 antitrypsin level in idiopathic interstitial pneumonia patients was 1.67 ± 0.33 g/L, and it was 1.54 ± 0.37 g/L in patients with nonidiopathic interstitial pneumonia (P = 0.13). Low alpha-1 antitrypsin levels were more frequently observed in nonidiopathic interstitial pneumonia patients compared with idiopathic interstitial pneumonia, but the difference was not statistically significant (8.9% vs. 0%, respectively, P = 0.4). In 100 patients, the normal PiMM genotype was detected, while abnormal ones (PiMZ, n = 2, 1.9%; PiMS, n = 1, 0.97%) were determined in three cases. When the frequency of alpha-1 antitrypsin polymorphism in interstitial lung disease patients was compared with the data of the healthy population, no significant difference was detected for the PiMZ and PiMS variants (P = 0.15 and P = 0.44, respectively).

CONCLUSION

Lower levels of serum alpha-1 antitrypsin were more frequent in nonidiopathic interstitial pneumonia patients than idiopathic interstitial pneumonia without an increase in genetic polymorphism. The difference was not statistically significant.

An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management

This document is an international evidence-based guideline on the diagnosis and management of idiopathic pulmonary fibrosis, and is a collaborative effort of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association. It represents the current state of knowledge regarding idiopathic pulmonary fibrosis (IPF), and contains sections on definition and epidemiology, risk factors, diagnosis, natural history, staging and prognosis, treatment, and monitoring disease course. For the diagnosis and treatment sections, pragmatic GRADE evidence-based methodology was applied in a question-based format. For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. It is emphasized that clinicians must spend adequate time with patients to discuss patients' values and preferences and decide on the appropriate course of action.

Idiopathic pulmonary fibrosis: is it a familial disease?

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis is a progressively fatal interstitial lung disease associated with pathological findings of usual interstitial pneumonia. Its pathogenesis is unknown, and there are no proven effective therapies. Familial cases account for 0.5-2% of idiopathic pulmonary fibrosis. Familial idiopathic pulmonary fibrosis occurs as an autosomal dominant disorder with variable penetrance. The clinical characteristics of familial idiopathic pulmonary fibrosis are indistinguishable from sporadic idiopathic pulmonary fibrosis. These marked similarities support the hypothesis there may, in part, be a genetic basis for idiopathic pulmonary fibrosis.

RECENT FINDINGS

Many investigations have evaluated genetic polymorphisms and idiopathic pulmonary fibrosis. Candidate genes include cytokines and surfactant protein genes. To date, no gene has been consistently identified to be associated with idiopathic pulmonary fibrosis. Recent studies in familial idiopathic pulmonary fibrosis have demonstrated a strong association with surfactant protein C gene mutations in one large kindred.

SUMMARY

The pathogenesis of both idiopathic pulmonary fibrosis and familial idiopathic pulmonary fibrosis remains unclear. A consistent genetic basis has not yet been demonstrated in all cases. Other factors, including variable gene expression, co-carriage of other modifying genes and environmental stimuli, particularly cigarette smoke, significantly contribute to disease expression.

Lymphangioleiomyomatosis and SZ alpha(1)-antitrypsin disease: a unique combination?

We describe a case of a 37-year-old female ex-smoker with lymphangioleiomyomatosis and SZ alpha(1)-antitrypsin disease who underwent successful bilateral sequential lung transplantation. While this disease combination has not been described previously, we recommend vigilance for the possibility of such combinations in patients with chronic lung disease. The possible mechanisms of interaction resulting from both disease processes are discussed.

Heterozygosity for a surfactant protein C gene mutation associated with usual interstitial pneumonitis and cellular nonspecific interstitial pneumonitis in one kindred

Familial pulmonary fibrosis is a heterogeneous group of interstitial lung diseases of unknown cause that is associated with multiple pathologic subsets. Mutations in the surfactant protein C (SP-C) gene (SFTPC) are associated with familial desquamative and nonspecific interstitial pneumonitis. Genetic studies in familial usual interstitial pneumonitis have been inconclusive. Using a candidate gene approach, we found a heterozygous exon 5 + 128 T-->A transversion of SFTPC in a large familial pulmonary fibrosis kindred, including adults with usual interstitial pneumonitis and children with cellular nonspecific interstitial pneumonitis. The mutation is predicted to substitute a glutamine for a conserved leucine residue and may hinder processing of SP-C precursor protein. SP-C precursor protein displayed aberrant subcellular localization by immunostaining. Electron microscopy of affected lung revealed alveolar type II cell atypia, with numerous abnormal lamellar bodies. Mouse lung epithelial cells transfected with the SFTPC mutation were notable for similar electron microscopy findings and for exaggerated cellular toxicity. We show that an SFTPC mutation segregates with the pulmonary fibrosis phenotype in this kindred and may cause type II cellular injury. The presence of two different pathologic diagnoses in affected relatives sharing this mutation indicates that in this kindred, these diseases may represent pleiotropic manifestations of the same central pathogenesis.

Fibrosing alveolitis in patients with rheumatoid arthritis as assessed by high resolution computed tomography, chest radiography, and pulmonary function tests

BACKGROUND

Fibrosing alveolitis (FA) is a common and serious complication of rheumatoid arthritis (RA). Before the availability of high resolution computed tomographic (HRCT) scanning, it was difficult to diagnose accurately without recourse to biopsy. Prospective studies have reported a prevalence of interstitial lung disease (ILD) of 19-44%. The term ILD used by these authors encompasses a variety of appearances on HRCT scans. This prospective study used HRCT scanning to determine the true prevalence of FA in hospital outpatients with RA, and to study associated clinical characteristics.

METHODS

One hundred and fifty consecutive patients with RA were selected from a hospital outpatient department, irrespective of the presence or absence of chest disease. All underwent a detailed clinical assessment, chest HRCT scanning, and conventional chest radiography within 4 weeks of full pulmonary function tests.

RESULTS

Seventy percent of patients were current or reformed cigarette smokers. Twenty eight (19%) had FA, most frequently of reticular pattern, and 12 of this group (43%) also had emphysematous bullae. None of the previously suggested risk factors for developing FA were confirmed. Fifty four percent of patients with HRCT evidence of FA had bilateral basal chest crackles, 82% had a reduced carbon monoxide transfer factor (TLCO), 14% had restrictive pulmonary function tests, and 14% had bilateral chest radiographic signs of FA.

CONCLUSIONS

HRCT evidence of FA was present in 19% of hospital outpatients with RA. Abnormalities on chest examination or on full pulmonary function tests, even without restrictive changes or chest radiographic abnormalities, should prompt physicians to request a chest HRCT scan when investigating dyspnoea in patients with RA.

Fibrosing alveolitis in patients with rheumatoid arthritis as assessed by high resolution computed tomography, chest radiography, and pulmonary function tests

BACKGROUND

Fibrosing alveolitis (FA) is a common and serious complication of rheumatoid arthritis (RA). Before the availability of high resolution computed tomographic (HRCT) scanning, it was difficult to diagnose accurately without recourse to biopsy. Prospective studies have reported a prevalence of interstitial lung disease (ILD) of 19–44%. The term ILD used by these authors encompasses a variety of appearances on HRCT scans. This prospective study used HRCT scanning to determine the true prevalence of FA in hospital outpatients with RA, and to study associated clinical characteristics.

METHODS

One hundred and fifty consecutive patients with RA were selected from a hospital outpatient department, irrespective of the presence or absence of chest disease. All underwent a detailed clinical assessment, chest HRCT scanning, and conventional chest radiography within 4 weeks of full pulmonary function tests.

RESULTS

Seventy percent of patients were current or reformed cigarette smokers. Twenty eight (19%) had FA, most frequently of reticular pattern, and 12 of this group (43%) also had emphysematous bullae. None of the previously suggested risk factors for developing FA were confirmed. Fifty four percent of patients with HRCT evidence of FA had bilateral basal chest crackles, 82% had a reduced carbon monoxide transfer factor (Tlco), 14% had restrictive pulmonary function tests, and 14% had bilateral chest radiographic signs of FA.

CONCLUSIONS

HRCT evidence of FA was present in 19% of hospital outpatients with RA. Abnormalities on chest examination or on full pulmonary function tests, even without restrictive changes or chest radiographic abnormalities, should prompt physicians to request a chest HRCT scan when investigating dyspnoea in patients with RA.

Recent advances in the aetiology of cryptogenic fibrosing alveolitis

Crytogenic fibrosing alveolitis is the commonest intersititial lung disease but, until recently, very little has been known about its aetiology. The histopathologist usually sees this disease at transbronchial biopsy or at autopsy. This article reviews the current knowledge of the aetiology of cryptogenic fibrosing alveolitis looking at possible infective, occupational, drug-related, smoking-associated, genetic and dietary factors. Knowledge of the possible roles of these factors in the disease process informs histopathologists when they are reporting these biopsies and enables them to make a larger contribution to defining the pathogenetic mechanisms.

Alpha-1 antitrypsin deficiency alleles and severe cystic fibrosis lung disease

BACKGROUND

Alpha-1 antitrypsin (alpha 1-AT) is the most abundant proteinase inhibitor within the lung. We have recently reported the surprising observation that cystic fibrosis patients with mild to moderate deficiency of alpha 1-antitrypsin have significantly better pulmonary function than non-deficient patients. This study may have been biased as it did not include the most severely affected patients who have died in childhood or those who have undergone orthotopic lung transplantation. The prevalence of alpha 1-antitrypsin deficiency alleles in this most severely affected group of patients with cystic fibrosis was therefore assessed.

METHODS

DNA was obtained from neonatal blood spots from children with cystic fibrosis who had died from pulmonary disease and from formalin fixed lung tissue from transplanted cystic fibrosis patients. The common S and Z deficiency alleles of alpha 1-AT were sought by amplification mutagenesis of the appropriate region of the alpha 1-AT gene followed by restriction enzyme digestion with Xmn I and Taq I, respectively.

RESULTS

Seventy-nine patients were identified (seven dead, 72 transplanted). Two patients (2.5%) were heterozygous for the Z allele of alpha 1-AT and four (5.1%) were heterozygous for the S allele. This is not significantly different from the incidence in the normal population of 4% and 8% for the S and Z alleles, respectively.

CONCLUSIONS

These data support previous findings that deficiency of alpha 1-AT is not associated with more severe pulmonary disease in cystic fibrosis and may be associated with milder lung disease. Further work is needed to clarify the mechanisms underlying the progressive lung damage in cystic fibrosis.