Potential Association Between Changes in Microbiota Level and Lung Diseases: A Meta-Analysis

Objective:Lung microbiota is increasingly implicated in multiple types of respiratory diseases. However, no study has drawn a consistent conclusion regarding the relationship between changes in the microbial community and lung diseases. This study verifies the association between microbiota level and lung diseases by performing a meta-analysis.Methods:Literature databases, including PubMed, ISI Web of Science, Embase, Google Scholar, PMC, and CNKI, were used to collect related articles published before March 20, 2021. The standard mean deviation (SMD) and related 95% confidence intervals (CIs) were calculated using a random-effects model. Subgroup, sensitivity, and publication bias analyses were also conducted.Results:Six studies, comprising 695 patients with lung diseases and 176 healthy individuals, were included in this meta-analysis. The results indicated that the microbiota level was higher in patients with lung diseases than in healthy individuals (SMD = 0.39, 95% CI = 0.22–0.55, I2 = 91.5%, P < 0.01). Subgroup analysis based on country demonstrated that the microbiota level was significantly higher in Chinese (SMD = 1.90, 95% CI = 0.87–2.93, I2 = 62.3%, P < 0.01) and Korean (SMD = 0.24, 95% CI = 0.13–0.35, I2 = 78.7%, P < 0.01) patients with lung diseases. The microbiota level of patients with idiopathic pulmonary fibrosis (IPF) (SMD = 1.40, 95% CI = 0.42–2.38, I2 = 97.3%, P = 0.005), chronic obstructive pulmonary disease (COPD) (SMD = 0.30, 95% CI = 0.09–0.50, I2 = 83.9%, P = 0.004), and asthma (SMD = 0.19, 95% CI = 0.06–0.32, I2 = 69.4%, P = 0.004) were significantly higher than those of the healthy group, whereas a lower microbiota level was found in patients with chronic hypersensitivity pneumonitis (CHP). The microbiota level significantly increased when the disease sample size was >50. Subgroup analysis based on different microbiota genera, indicated that Acinetobacter baumannii and Pseudomonas aeruginosa were significantly increased in COPD and asthma diseases.Conclusion:We observed that patients with IPF, COPD, and asthma had a higher microbiota level, whereas patients with CHP had a lower microbiota level compared to the healthy individuals. The level of A. baumannii and P. aeruginosa were significantly higher in patients with COPD and asthma, and thus represented as potential microbiota markers in the diagnosis and treatment of lung diseases.

Common idiopathic pulmonary fibrosis risk variants are associated with hypersensitivity pneumonitis

A subset of patients with hypersensitivity pneumonitis (HP) develop lung fibrosis that is clinically similar to idiopathic pulmonary fibrosis (IPF). To address the aetiological determinants of fibrotic HP, we investigated whether the common IPF genetic risk variants were also relevant in study subjects with fibrotic HP. Our findings indicate that common genetic variants in TERC, DSP, MUC5B and IVD were significantly associated with fibrotic HP. These findings provide support for a shared etiology and pathogenesis between fibrotic HP and IPF.

Clinical, radiologic, and morphological diagnosis of hypersensitivity pneumonitis

Aim. To study the relationship between clinical, radiologic, and morphological features in nonfibrotic and fibrotic hypersensitivity pneumonitis.Materials and methods. Clinical symptoms, data of high-resolution computed tomography, parameters of external respiration, and histological changes in the lung tissue obtained via open and transbronchial biopsies were studied retrospectively in 175 patients with hypersensitivity pneumonitis (HP). Statistical analysis was performed using the Statistica software.Results. We found that the clinical error rate in the diagnosis of HP was 84.5%, among pathologists – 92%. Among all the variants of HP, the most common was fibrotic HP. It was shown that non-necrotizing granulomas and giant cells in the cavities of the alveoli, microcells, and interalveolar septa were more typical of nonfibrotic HP. In fibrotic HP, peribronchial fibrosis, smooth muscle metaplasia in fibrotic areas, and the presence of fibroblastic foci in the walls of terminal bronchioles are signs of differential diagnosis with usual interstitial pneumonia. The classical triad of histological signs was observed in 19.2% of patients with nonfibrotic HP and in 5.6% of patients with fibrotic HP.Conclusion. Diagnosis of HP is complex and should be based on a multidisciplinary approach involving clinicians (pulmonologists), radiologists, functional diagnostics specialists, and pathologists. In this case, it is imperative to take into account and identify factors causing development of the disease, as well as the age of patients.

NMR metabolomic and microarray-based transcriptomic data integration identifies unique molecular signatures of hypersensitivity pneumonitis

This original article focuses on integrated metabolomics and transcriptomics analysis to understand the pathogenesis of hypersensitivity pneumonitis (HP).

Accuracy of Inhalation Challenge Test for Bird-related Fibrotic Hypersensitivity Pneumonitis: a Case Control Study

Background: The inhalation challenge test is considered to be the “gold standard” for diagnosis of hypersensitivity pneumonitis (HP) and identifying the causative antigen in patients with fibrotic HP. However, the inhalation challenge test is not widely used. This study aimed to examine the value of the inhalation challenge test.Methods: This was a single-center, case control study. The patients with fibrotic HP were diagnosed pathologically by surgical lung biopsy or transbronchial lung cryobiopsy, and were assumed to be bird-related fibrotic HP if they had a history of obvious avian exposure. The patients with a histopathological diagnosis of fibrotic HP, no history of bird exposure and negative anti-bird antibodies were assumed to be non-bird-related fibrotic HP.Results: Based on pathological findings and history of avian exposure, 43 of 86 patients were diagnosed with bird-related fibrotic HP. In 43 patients with bird-related fibrotic HP, 15 (35%) were positive for anti-bird IgG antibody, and 36 (81%) were positive for the inhalation challenge test. Patients with both positive inhalation challenge test and anti-bird IgG antibodies had a 2.7% decline in annual FVC before the inhalation (p = 0.029). In patients with positive inhalation challenge test and the negative anti-bird IgG antibodies, the annual FVC decreased by 5.0% (p = 0.047). No significant FVC decline was observed in patients with negative inhalation challenge test and positive anti-bird IgG antibody, and those with both negative tests.Conclusions: The inhalation challenge test for bird-related fibrotic HP was more sensitive than anti-bird IgG antibodies. Furthermore, the inhalation challenge test was able to find a group of patients with FVC decline.

High-Resolution Computed Tomography Based Comparative Analysis of Asbestosis vs. Fibrotic Hypersensitivity Pneumonitis

BackgroundAsbestosis and fibrotic hypersensitivity pneumonitis (FHP) are fibrotic interstitial lung diseases that develop secondary to inhalation exposure. The differential diagnosis is based on clinical evaluation of imaging findings, particularly in developing countries. We compared the imaging features between asbestosis and FHP to gain a better understanding of the differential diagnostic value of these conditions.MethodsThis comparative study included 204 patients with asbestosis and 74 patients with FHP. We compared patients’ clinical data and chest high-resolution computed tomography (HRCT) images obtained from a predesigned chart. The International Classification of HRCT for Occupational and Environmental Respiratory Diseases was used to categorize chest imaging findings in patients. Diagnostic tests were used to compare the imaging features of asbestosis and FHP.ResultsPatients with asbestosis were older and had a longer latent period until disease manifestation than those with FHP. Asbestosis was characterized by irregular and/or linear opacities, with lower lung preponderance, accompanied by ground-glass opacities and mosaic attenuation. Notably, 98.5% of patients with asbestosis showed benign pleural abnormalities, and >33% of these patients had diffuse pleural thickening with parenchymal bands and/or rounded atelectasis. Abnormalities of the mediastinal and diaphragmatic pleura were observed only in cases of asbestosis, and this finding showed high specificity for the diagnosis for asbestosis compared with that for FHP. Subpleural dots or diaphragmatic pleural abnormalities showed moderate sensitivity and high specificity for diagnosis of asbestosis compared with that for FHP. Interobserver reliability was good for evaluation of imaging findings including honeycombing, pleural calcification, lymphadenectasis, and lymph node calcification.ConclusionsHRCT-based imaging findings can distinguish between asbestosis and FHP to a certain extent, particularly with regard to subpleural dots and diaphragmatic pleural abnormalities that characterize the former.