Next-Generation Metagenome Sequencing Shows Superior Diagnostic Performance in Acid-Fast Staining Sputum Smear-Negative Pulmonary Tuberculosis and Non-tuberculous Mycobacterial Pulmonary Disease

In this study, we explored the clinical value of next-generation metagenome sequencing (mNGS) using bronchoalveolar lavage fluid (BALF) samples from patients with acid-fast staining (AFS) sputum smear-negative pulmonary tuberculosis (PTB) and non-tuberculous mycobacterial pulmonary disease (NTM-PD). Data corresponding to hospitalized patients with pulmonary infection admitted to the hospital between July 2018 and July 2021, who were finally diagnosed with AFS sputum smear-negative PTB and NTM-PD, were retrospectively analyzed. Bronchoscopy data as well as mNGS, Xpert, AFS (BALF analysis), and T-SPOT (blood) data, were extracted from medical records. Thereafter, the diagnostic performances of these methods with respect to PTB and NTM-PD were compared. Seventy-one patients with PTB and 23 with NTM-PD were included in the study. The sensitivities of mNGS, Xpert, T-SPOT, and AFS for the diagnosis of PTB were 94.4% (67/71), 85.9% (61/71), 64.8% (46/71), and 28.2% (20/71), respectively, and the diagnostic sensitivity of mNGS combined with Xpert was the highest (97.2%, 67/71). The specificity of Xpert was 100%, while those of AFS and T-SPOT were 73.9% (17/23) and 91.3% (21/23), respectively. Further, the 23 patients with NTM-PD could be identified using mNGS, and in the population with immunosuppression, the sensitivities of mNGS, Xpert, T-SPOT, and AFS were 93.5% (29/31), 80.6% (25/31), 48.4% (15/31), and 32.3% (10/31), respectively, and the diagnostic sensitivity of mNGS combined with Xpert was the highest (100%, 31/31). The specificities of Xpert and T-SPOT in this regard were both 100%, while that of AFS was 40% (2/5). Furthermore, using mNGS, all the NTM samples could be identified. Thus, the analysis of BALF samples using mNGS has a high accuracy in the differential diagnosis of MTB and NTM. Further, mNGS combined with Xpert can improve the detection of MTB, especially in AFS sputum smear-negative samples from patients with compromised immune states or poor responses to empirical antibiotics.

Modulation of Pulmonary Toxicity in Metabolic Syndrome Due to Variations in Iron Oxide Nanoparticle-Biocorona Composition

Nanoparticles (NPs) interact with biomolecules by forming a biocorona (BC) on their surface after introduction into the body and alter cell interactions and toxicity. Metabolic syndrome (MetS) is a prevalent condition and enhances susceptibility to inhaled exposures. We hypothesize that distinct NP-biomolecule interactions occur in the lungs due to MetS resulting in the formation of unique NP-BCs contributing to enhanced toxicity. Bronchoalveolar lavage fluid (BALF) was collected from healthy and MetS mouse models and used to evaluate variations in the BC formation on 20 nm iron oxide (Fe₃O₄) NPs. Fe₃O₄ NPs without or with BCs were characterized for hydrodynamic size and zeta potential. Unique and differentially associated proteins and lipids with the Fe₃O₄ NPs were identified through proteomic and lipidomic analyses to evaluate BC alterations based on disease state. A mouse macrophage cell line was utilized to examine alterations in cell interactions and toxicity due to BCs. Exposures to 6.25, 12.5, 25, and 50 μg/mL of Fe₃O₄ NPs with BCs for 1 h or 24 h did not demonstrate overt cytotoxicity. Macrophages increasingly associated Fe₃O₄ NPs following addition of the MetS BC compared to the healthy BC. Macrophages exposed to Fe₃O₄ NPs with a MetS-BC for 1 h or 24 h at a concentration of 25 μg/mL demonstrated enhanced gene expression of inflammatory markers: CCL2, IL-6, and TNF-α compared to Fe₃O₄ NPs with a healthy BC. Western blot analysis revealed activation of STAT3, NF-κB, and ERK pathways due to the MetS-BC. Specifically, the Jak/Stat pathway was the most upregulated inflammatory pathway following exposure to NPs with a MetS BC. Overall, our study suggests the formation of distinct BCs due to NP exposure in MetS, which may contribute to exacerbated inflammatory effects and susceptibility.

Pneumocystis jirovecii pneumonia in a patient receiving chemotherapy for advanced prostatic cancer: a case report

Pneumocystis jirovecii pneumonia (PJP) in advanced prostatic cancer patients not receiving high-dose glucocorticoids has been reported rarely. A 73-year-old man underwent chemotherapy with cisplatin and docetaxel for advanced prostatic cancer. After nine cycles of chemotherapy, he developed a high fever, dry cough, shortness of breath, and severe fatigue, with rapid-onset hypoxic respiratory failure. Investigations demonstrated bilateral ground-glass opacities with positive bronchoalveolar lavage fluid (BALF) for Pneumocystis jirovecii by next-generation sequencings (NGS). The patient recovered well with treatment with trimethoprim-sulfamethoxazole, caspofungin, and corticosteroids. This case report describes a case of PJP in a patient with a solid tumor who did not receive high-dose glucocorticoids and emphasizes the importance of early diagnosis and treatment.

A Distinct Dexamethasone-Dependent Gene Expression Profile in the Lungs of COVID-19 Patients

The effects of dexamethasone (DXM) treatment on pulmonary immunity in COVID-19-associated acute respiratory distress syndrome (CARDS) remain insufficiently understood. We performed transcriptomic RNA-seq analysis of bronchoalveolar lavage fluid from 20 mechanically ventilated patients: 12 with CARDS (with or without DXM) and 8 non-COVID-19 critically ill controls. CARDS with DXM was characterized by upregulation of genes related to B-cell and complement pathway activation, antigen presentation, phagocytosis, and FC-γ receptor signaling. Most interferon-stimulated genes were upregulated in CARDS, particularly in CARDS without DXM. In conclusion, DXM treatment was not associated with regulation of proinflammatory pathways in CARDS but with regulation of other local immune responses. Clinical Trials Registration. NCT04354584.

Clinical application of metagenomic next-generation sequencing technology in the diagnosis and treatment of pulmonary infection pathogens: A prospective single-center study of 138 patients

Introduction

Rapid and accurate pathogen identification is essential for the treatment of pneumonia. Metagenomic next‐generation sequencing (mNGS) is a newly developed technology to obtain microbial nucleic acid sequence information quickly, efficiently, and without bias.

Methods

We performed shotgun metagenomic next‐generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) for pathogen identification in pneumonia in a prospective study with 138 patients from a single center. We compared the results of mNGS with standard methods including culture, staining, and targeted PCR and evaluated the clinical applicability of mNGS.

Results

Most of the patients (128/138, 92.75%) were cured or improved. One patient (1/138, 0.72%) died because of acute gastrointestinal bleeding, and 9 patients (9/138, 6.52%) showed no improvement. mNGS identified more bacteria (53 versus 27), fewer fungi (8 versus 31), and more viruses (16 versus 1) than standard methods. In total, treatment in 34 out of 138 cases (24.64%) was adjusted and optimized because of mNGS results. Positive mNGS results contributed to a definitive diagnosis in 23 cases (16.67%), which helped guide treatment decision by either adjusting the antibiotics without de‐escalation or continuing the empirical treatment. mNGS also confirmed no active infection in 11 cases (7.97%) allowed for antibiotic de‐escalation.

Conclusion

This prospective clinical study evaluated the clinical utility of mNGS for the diagnosis of pneumonia and showed that mNGS of BALF provides valuable information for effective treatment.

Proteomic Network Analysis of Bronchoalveolar Lavage Fluid in Ex-Smokers to Discover Implicated Protein Targets and Novel Drug Treatments for Chronic Obstructive Pulmonary Disease

Bronchoalveolar lavage of the epithelial lining fluid (BALF) can sample the profound changes in the airway lumen milieu prevalent in chronic obstructive pulmonary disease (COPD). We compared the BALF proteome of ex-smokers with moderate COPD who are not in exacerbation status to non-smoking healthy control subjects and applied proteome-scale translational bioinformatics approaches to identify potential therapeutic protein targets and drugs that modulate these proteins for the treatment of COPD. Proteomic profiles of BALF were obtained from (1) never-smoker control subjects with normal lung function (n = 10) or (2) individuals with stable moderate (GOLD stage 2, FEV1 50−80% predicted, FEV1/FVC < 0.70) COPD who were ex-smokers for at least 1 year (n = 10). After identifying potential crucial hub proteins, drug−proteome interaction signatures were ranked by the computational analysis of novel drug opportunities (CANDO) platform for multiscale therapeutic discovery to identify potentially repurposable drugs. Subsequently, a literature-based knowledge graph was utilized to rank combinations of drugs that most likely ameliorate inflammatory processes. Proteomic network analysis demonstrated that 233 of the >1800 proteins identified in the BALF were significantly differentially expressed in COPD versus control. Functional annotation of the differentially expressed proteins was used to detail canonical pathways containing the differential expressed proteins. Topological network analysis demonstrated that four putative proteins act as central node proteins in COPD. The drugs with the most similar interaction signatures to approved COPD drugs were extracted with the CANDO platform. The drugs identified using CANDO were subsequently analyzed using a knowledge-based technique to determine an optimal two-drug combination that had the most appropriate effect on the central node proteins. Network analysis of the BALF proteome identified critical targets that have critical roles in modulating COPD pathogenesis, for which we identified several drugs that could be repurposed to treat COPD using a multiscale shotgun drug discovery approach.

Application of metagenomic next-generation sequencing for bronchoalveolar lavage diagnostics in patients with lower respiratory tract infections

Objective

Metagenomic next-generation sequencing (mNGS) has the potential to overcome the shortcomings of traditional culture methods. This study aimed to assess the diagnostic value of mNGS in patients with lower respiratory tract infections (LRTIs).

Methods

This retrospective observational study sequentially enrolled 47 patients with LRTIs admitted to Shenzhen Hospital of Southern Medical University between February 2019 and November 2020. Pathogens in bronchoalveolar lavage fluid (BALF) samples were investigated to compare diagnoses by mNGS with culture methods.

Results

Compared with culture methods, mNGS had a diagnostic sensitivity of 80% and a specificity of 35.13% with an agreement rate of 44.68% between these two methods. mNGS significantly increased the pathogen detection rate.

Conclusions

mNGS may show some advantages in identifying a wide range of LRTI pathogens, improving the sensitivity for viruses and atypical pathogens. The clinical application of NGS technology is worth looking forward to.

Expression of S100A9 and KL-6 in common interstitial lung diseases

By evaluating S100 calcium binding protein A9 (S100A9) and Klebs von den Lungen-6 (KL-6) expression in patients with 4 common interstitial lung diseases (ILDs), we aimed to investigate whether S100A9 or KL-6 can be of any value in the differential diagnosis of these ILDs and simultaneously signal the disease progression.We collected the data of patients diagnosed with the 4 ILDs and underwent fiber-optic bronchoscopy and BAL in the First Affiliated Hospital, China Medical University from January 2012 to December 2020. The data related to BGA, C-reactive protein, pulmonary function test, total number and fraction of cells, T lymphocyte subsets in bronchoalveolar lavage fluid (BALF), and the expression of S100A9 and KL-6 in BALF and serum were collected. We analyzed, whether S100A9 or KL-6 could serve as a biomarker for differential diagnosis between the 4 common ILDs; whether the levels of S100A9 and KL-6 correlated with each other; whether they were correlated with other clinical parameters and disease severity.This study included 98 patients, 37 patients with idiopathic pulmonary fibrosis (IPF), 12 with hypersensitivity pneumonitis, 13 with connective tissue disease-associated ILD, and 36 with sarcoidosis (SAR): stage I (18), stage II (9), stage III (5), and stage IV (4). The expression of KL-6 in BALF was significantly higher in IPF patients than other 3 groups (all P-value < .05). However, there was no significant difference in the levels of S100A9 in BALF and serum between the 4 groups (P-value > .05). The levels of S100A9 in BALF of IPF patients was positively and significantly correlated with KL-6 expression and the percentage of neutrophils in BALF (P-value < .05). Along with the stage increase of SAR patients, the level of S100A9 in BALF gradually increased, which was negatively and significantly correlated with the forced vital capacity/predicted, carbon monoxide diffusing capacity/predicted%, and PaO2 (all P-value < .05).The expression of KL-6 in BALF can be used as a biomarker to differentiate IPF from the other 3 common ILDs. While, this was not the case with expression of S100A9 in BALF and serum. However, the expression S100A9 in BALF is useful to indicate the progression of SAR. Thus, simultaneous measurement of KL-6 and S100A9 levels in BALF makes more sense in differential diagnosing of the 4 common ILDS.

Combined Radiographic Features and Age Can Distinguish Mycoplasma pneumoniae Pneumonia from Other Bacterial Pneumonias: Analysis Using the 16S rRNA Gene Sequencing Data

The study objective was to evaluate chest radiographic features that distinguish Mycoplasma pneumoniae pneumonia (MPP) from other bacterial pneumonias diagnosed based on the bacterial floral analysis with 16S rRNA gene sequencing, using bronchoalveolar lavage fluid samples directly obtained from pneumonia lesions. Patients were grouped according to the dominant bacterial phenotype; among 120 enrolled patients with CAP, chest CT findings were evaluated in 55 patients diagnosed with a mono-bacterial infection (one bacterial phylotype occupies more than 80% of all phylotypes in a sample) by three authorized respiratory physicians. Among this relatively small sample size of 55 patients with CAP, 10 had MPP, and 45 had other bacterial pneumonia and were categorized into four groups according to their predominant bacterial phylotypes. We created a new scoring system to discriminate MPP from other pneumonias, using a combination of significant CT findings that were observed in the M. pneumoniae group, and age (<60 years) (MPP−CTA scoring system). When the cutoff value was set to 1, this scoring system had a sensitivity of 80%, a specificity of 93%, a positive predictive value of 73%, and a negative predictive value of 95%. Among the CT findings, centrilobular nodules were characteristic findings in patients with MPP, and a combination of chest CT findings and age might distinguish MPP from other bacterial pneumonias.

Metabolic Landscape of Bronchoalveolar Lavage Fluid in Coronavirus Disease 2019 at Single Cell Resolution

Abnormal function of immune cells is one of the key mechanisms leading to severe clinical symptoms in coronavirus disease 2019 patients, and metabolic pathways can destroy the function of the immune system by affecting innate and adaptive immune responses. However, the metabolic characteristics of the immune cells of the SARS-CoV-2 infected organs in situ remaining elusive. We reanalyzed the metabolic-related gene profiles in single-cell RNA sequencing data, drew the metabolic landscape in bronchoalveolar lavage fluid immune cells, and elucidated the metabolic remodeling mechanism that might lead to the progression of COVID-19 and the cytokine storm. Enhanced glycolysis is the most important common metabolic feature of all immune cells in COVID-19 patients. CCL2⁺ T cells, Group 2 macrophages with high SPP1 expression and myeloid dendritic cells are among the main contributors to the cytokine storm produced by infected lung tissue. Two metabolic analysis methods, including Compass, showed that glycolysis, fatty acid metabolism, bile acid synthesis and purine and pyrimidine metabolism levels of CCL2⁺ T cells, Group 2 macrophages and myeloid dendritic cells were upregulated and correlated with cytokine storms of COVID-19 patients. This might be the key metabolic regulatory factor for immune cells to produce large quantities of cytokines.

Invasive aspergillosis in coronavirus disease 2019: a practical approach for clinicians

PURPOSE OF REVIEW

Invasive pulmonary aspergillosis (IPA) can affect patients with severe coronavirus disease 2019 (COVID-19), but many questions remain open about its very variable incidence across the world, the actual link between the viral infection and the fungal superinfection, the significance of Aspergillus recovery in a respiratory sample, and the management of such cases. This review addresses these questions and aims at providing some clues for the practical diagnostic and therapeutic approaches of COVID-19-associated pulmonary aspergillosis (CAPA) in a clinical perspective.

RECENT FINDINGS

Definitions have been proposed for possible/probable/proven CAPA, but distinction between colonization and invasive fungal infection is difficult and not possible in most cases in the absence of histopathological proof or positive galactomannan in serum. Most importantly, the recovery of an Aspergillus by a direct (culture, PCR) or indirect (galactomannan) test in a respiratory sample is an indicator of worse outcome, which justifies a screening for early detection and initiation of preemptive antifungal therapy in such cases.

SUMMARY

The COVID-19 pandemic has increased our awareness of IPA among ICU patients. Although current recommendations are mainly based on experts' opinions, prospective studies are needed to get more evidence-based support for the diagnostic approach and management of CAPA.

Neutrophils in Bronchoalveolar Lavage Fluid Indicating the Severity and Relapse of Pulmonary Sarcoidosis

BACKGROUND

Pulmonary sarcoidosis is a highly heterogeneous granulomatous disease without any specific symptoms and manifestations. Neutrophils in bronchoalveolar lavage fluid (BALF) have been proposed to indicate the severity and prognosis of pulmonary sarcoidosis, but this needs confirmation in patients from different populations due to the heterogeneity of the disease. This study aimed to determine the characteristics of patients with pulmonary sarcoidosis in northeastern China and to explore the relationship between neutrophils in BALF and the severity of pulmonary sarcoidosis.

METHODS

We enrolled 432 patients who were diagnosed with pulmonary sarcoidosis in this retrospective study. The symptoms, extrapulmonary involvement, forced vital capacity percentage predicted (FVC % pred), and diffusing capacity of the lung for carbon monoxide percentage predicted (DLco % pred) were recorded. BAL was performed in 319 patients, and the results of a cellular examination of BALF were collected. A total of 123 patients who received corticosteroid treatment were followed up for at least 12 months, and the outcomes were recorded.

RESULTS

Cough was the most common symptom, and cutaneous involvement was the most common extrapulmonary manifestation in 304 (70.4%) and 82 (19.0%) patients, respectively. The percentages of patients with high neutrophil counts in BALF (>3%) were higher at Stages 2 and 3 compared with Stages 0 and 1 (33.2 vs. 19.4%, p = 0.007), although the percentages of neutrophils in BALF showed no difference between patients at Stages 0, 1, 2, and 3. Patients with high neutrophil counts in BALF had lower FVC % pred compared with the other patients (79.5 ± 18.2 vs. 84.9 ± 14.5%, p = 0.025) and were prone to relapse after corticosteroids were tapered. High neutrophil counts in BALF were independently associated with relapse after corticosteroids were tapered in a binary logistic regression analysis (p = 0.027).

CONCLUSIONS

Patients with pulmonary sarcoidosis lacked specific symptoms and manifestations. The neutrophil count in BALF could indicate the severity and outcomes of pulmonary sarcoidosis.

The effect of different drugs on hard metal lung disease in a rat model

Hard metal lung disease (HMLD) drugs include dexamethasone sodium phosphate (Dex), methylprednisolone (MP) injection, N-acetylcysteine injection (NAC), and a mix of Dex, MP, and NAC (MIX). In this study, we compared the effects of these drugs on different cytokines of hard metal lung disease in a rat model. Thirty-six adult female Sprague Dawley rats were distributed equally into the control group, hard metal (HM) group, Dex group, MP group, NAC group, and MIX group. HM powder (0.5 mL, 20 mg/mL; one time) was administered by intraperitoneal injection to the HM group through the pulmonary endotracheal tube, while the control group received normal saline (0.5 mL, 20 mg/mL; one time). After 4 weeks, the drugs were administered to the experimental groups (0.5 mL, 20 mg/mL; one time). After 8 weeks, bronchoalveolar lavage fluid (BALF) and serum were examined for cytokine levels. Biochemical analysis indicated that the Dex, MP, NAC, and MIX did not improve TGF-β1, TGF-β2, KL-6, and MMP-1 in the BALF, while MIX increased TIMP-1 in BALF. In addition, the NAC treatment significantly increased the expression levels of TGF-β1, TGF-β2, KL-6, and MMP-1. The MIX treatment significantly increased the expression levels of TGF-β1, TGF-β2, and KL-6. The MP treatment significantly increased the expression levels of KL-6, and MMP-1. The Dex treatment significantly increased the expression levels of TGF-β1, KL-6, and MMP-1. This study demonstrated that administered with NAC and MIX could improve TGF-β1, TGF-β2, and KL-6 in serum of hard metal lung disease in a rat model. Therefore, NAC injection may be considered a useful candidate in the development of a preventive agent against HMLD.

Mechanical ventilation induces lung and brain injury through ATP production, P2Y1 receptor activation and dopamine release

Mechanical ventilation can induce lung injury and exacerbate brain injury due to lung-brain interaction. The current study sought to investigate the mechanism of lung-brain interaction induced by mechanical ventilation and offer theoretical insight into the management of ventilator-induced brain injury. The experimental mice were assigned into the spontaneously breathing group and the mechanical ventilation group and injected with dopamine (DA) receptor antagonist haloperidol or P2Y1 receptor antagonist MRS2279 before ventilation. In vitro assay was conducted using lung epithelial cells MLE-12 hippocampal neuron cells and HT-22. Mouse recognition function and lung injury were examined. The condition and concentration of neurons in the hippocampus were observed. The levels of several inflammatory factors, DA, adenosine triphosphate (ATP), P2Y1R, and dysbindin-1 were detected. Mechanical ventilation induced lung and brain injury in mice, manifested in increased inflammatory factors in the bronchoalveolar lavage fluid and hippocampus, prolonged escape latency, and swimming distance and time in the target quadrant with a weakened concentration of neurons in the hippocampus. Our results presented elevated ATP and P2Y1R expressions in the mechanically ventilated mice and stretched MLE-12 cells. The mechanically ventilated mice and P2Y1 receptor activator MRS2365-treated HT-22 cells presented with elevated levels of DA and dysbindin-1. Inactivation of P2Y1 receptor in the hippocampus or blockage of DA receptor alleviated brain injury induced by mechanical ventilation in mice. To conclude, the current study elicited that lung injury induced by mechanical ventilation exacerbated brain injury in mice by increasing ATP production, activating the P2Y1 receptor, and thus promoting DA release.

Clinical, Laboratory, Radiological, Bronchoscopic, and Outcome Characteristics of Pulmonary Fungal Infection in Children in PICU in Central China: A Case Series

OBJECTIVE

Fungal infections are common in pediatric intensive care units (PICUs), but the monitoring methods are limited. This study analyzed the differences in clinical features, diagnosis, and treatment between PICU patients with and without fungal infection.

METHODS

This retrospective study analyzed PICU patients at the Maternal and Child Health Hospital of Hubei Province diagnosed with severe pneumonia between January 2015 and January 2020. The patients were divided into the fungal (F) and non-fungal (NF) infection groups. Levels of 1,3-beta-D-glucan (BDG) and galactomannan (GM) in serum and bronchoalveolar lavage fluid (BALF) were analyzed. Chest computed tomography (CT) images were reviewed.

RESULTS

A total of 357 patients were included. In the F group, fever, moist rales, coarse rales, shortness of breath, and sepsis were more common (all P < 0.05); PICU time, hospitalization duration, and BDG- and GM-positive rates in serum and BALF were all significantly higher than in the NF group (all P < 0.05). The BDG- and GM-positive rates in serum and BALF were higher in the F than in the NF group (all P < 0.05). The abnormal lymphocyte ratios in serum were higher in the F group (all P < 0.05). Wedge-shaped, patchy, streaky shadows and subpleural reticulation were higher in CT images of the F group (all P < 0.05). Tracheobronchial stenosis was more common in pulmonary fibroscopy results of the F group (P = 0.04).

CONCLUSION

PICU pneumonia patients with fungal infection have specific clinical and laboratory features compared with those without fungal infection, including higher rates of BALF, serum BDG, GM positivity and tracheobronchial stenosis.

Pulmonary toxicity of sodium dichloroisocyanurate after intratracheal instillation in sprague-dawley rats

In water, sodium dichloroisocyanurate (NaDCC), a source for chlorine gas generation, releases free available chlorine in the form of hypochlorous acid, a strong oxidizing agent. NaDCC has been used as a disinfectant in humidifiers; however, its inhalation toxicity is a concern. Seven-week-old rats were exposed to NaDCC doses of 100, 500, and 2500 μg·kg^-1 body weight by intratracheal instillation (ITI) to investigate pulmonary toxicity. The rats were sacrificed at 1 d (exposure group) or 14 d (recovery group) after ITI. Despite a slight decrease in body weight after exposure, there was no statistically significant difference between the control and NaDCC-treated groups. A significant increase in the total protein level of the bronchoalveolar lavage fluid (BALF) was observed in the exposure groups. Lactate dehydrogenase leakage into the BALF increased significantly (p < 0.01) in the exposure groups; however, recovery was observed after 14 d. The measurement of cytokines in the BALF samples indicated a significant increase in interleukin (IL)-6 in the exposure group and IL-8 in the recovery group. Histopathological examination revealed inflammatory foci and pulmonary edema around the terminal bronchioles and alveoli. This study demonstrated that ITI of NaDCC induced reversible pulmonary edema and inflammation without hepatic involvement in rats.

Interleukin-6 in blood and bronchoalveolar lavage fluid of hospitalized children with community-acquired pneumonia

BACKGROUND

Host biomarkers and cytokines help in the prediction of disease severity in adults with community-acquired pneumonia (CAP). Accurate assessment of pathogens and disease severity is essential to clinical decision-making. There are few validated prognostic tools in blood and bronchoalveolar lavage for children with CAP to assist with proper decision and management.

METHODS

We performed a retrospective study of 118 children under 18 years of age, hospitalized for CAP with bronchoalveolar lavage management within the first 2 days. The primary outcome was disease severity: mild (with no complications), moderate (with mild to moderate complications), and severe (with severe complications). Comparison and performance analysis of biomarkers and cytokines in the blood or bronchoalveolar lavage fluid (BALF) across different severity categories/different pathogens were performed.

RESULTS

Analysis of 118 CAP cases revealed significant differences in the BALF levels of IL-6 (p = 0.000), CRP (p = 0.001), and ESR (p = 0.004) across different severity categories, while BALF IL-6 level was indicated as the best indicator to discriminate mild from moderate-to-severe cases with highest AUC (0.847, 95% CI: 0.748-0.946), fair sensitivity (0.839), and specificity (0.450), and severe from non-severe cases with highest AUC (0.847), sensitivity (0.917), and specificity (0.725). ALL biomarkers and cytokines exhibited no significant differences across different pathogen categories (p > 0.05), while BALF IL-6 (p = 0.000), blood ANC (p = 0.028), and ESR (p = 0.024) levels were obviously different in comparison to single Mycoplasma pneumoniae (MP)-, bacteria-, or virus-positive group vs. non-group. Blood CRP (r = 0.683, p = 0.000) and ESR (r = 0.512, p = 0.000) levels revealed significant correlation with the hospitalization course (HC). Among all the BALF cytokines, only BALF IL-6 showed a significant difference (p = 0.004, p < 0.01) across different severity categories, with good performance for predicting CAP severity in hospitalized children (AUC = 0.875, P = 0.004). Blood IL-6 and BALF IL-6 levels showed no significant correlation; in addition, BALF IL6 was better at predicting CAP severity in hospitalized children (AUC = 0.851, p = 0.011, p < 0.05) compared to blood IL-6.

CONCLUSION

BALF IL-6 and blood CRP levels, and ESR may have the ability for discriminating disease severity in hospitalized children with CAP, whereas WBC count and ANC have limited ability. No biomarkers or cytokines seemed to have the ability to predict the pathogen category, while BALF IL-6, blood ANC, and ESR may assist in the diagnosis of single MP, bacteria, and virus infections, respectively.

Characterization of Extracellular Vesicles from Bronchoalveolar Lavage Fluid and Plasma of Patients with Lung Lesions Using Fluorescence Nanoparticle Tracking Analysis

The current lack of reliable methods for quantifying extracellular vesicles (EVs) isolated from complex biofluids significantly hinders translational applications in EV research. The recently developed fluorescence nanoparticle tracking analysis (FL-NTA) allows for the detection of EV-associated proteins, enabling EV content determination. In this study, we present the first comprehensive phenotyping of bronchopulmonary lavage fluid (BALF)-derived EVs from non-small cell lung cancer (NSCLC) patients using classical EV-characterization methods as well as the FL-NTA method. We found that EV immunolabeling for the specific EV marker combined with the use of the fluorescent mode NTA analysis can provide the concentration, size, distribution, and surface phenotype of EVs in a heterogeneous solution. However, by performing FL-NTA analysis of BALF-derived EVs in comparison to plasma-derived EVs, we reveal the limitations of this method, which is suitable only for relatively pure EV isolates. For more complex fluids such as plasma, this method appears to not be sensitive enough and the measurements can be compromised. Our parallel presentation of NTA-based phenotyping of plasma and BALF EVs emphasizes the great impact of sample composition and purity on FL-NTA analysis that has to be taken into account in the further development of FL-NTA toward the detection of EV-associated cancer biomarkers.

Assessing the utility of the Xpert Mycobacterium tuberculosis/rifampin assay for analysis of bronchoalveolar lavage fluid in patients with suspected pulmonary tuberculosis

Background

There is limited research assessing the utility of the Xpert Mycobacterium tuberculosis/rifampin (MTB/RIF) assay for the analysis of bronchoalveolar lavage fluid (BALF) in Chinese patients with suspected pulmonary tuberculosis (PTB). Thus, our objective was to determine the diagnostic accuracy of the Xpert MTB/RIF assay and evaluate its utility for the determination of rifampicin resistance.

Methods

We retrospectively analyzed BALF from 214 patients with suspected PTB between January 2018 and March 2019. Using mycobacterial culture or final clinical diagnosis as the reference standard, the diagnostic accuracy of the smear microscopy (SM), tuberculosis bacillus DNA (TB‐DNA), Xpert MTB/RIF assay, and the determination of rifampicin resistance based on the Xpert MTB/RIF assay were compared.

Results

As compared to mycobacterial culture, the sensitivity of the Xpert MTB/RIF assay, SM, and TB‐DNA were 85.5% (74.2%–93.1%), 38.7% (26.6%–51.9%), and 67.7% (54.7%–79.1%), respectively. As compared to the final diagnosis, the specificity of the Xpert MTB/RIF assay, SM, and TB‐DNA were 100.0% (95.9%–100.0%), 94.3% (87.1%–98.1%), and 98.9% (93.8%–100.0%), respectively. The sensitivity and specificity of the rifampicin resistance detection using the Xpert MTB/RIF assay were 100% and 98.0%, respectively, with liquid culture as the reference.

Conclusions

This study demonstrates that the analysis of BALF with the Xpert MTB/RIF assay provides a rapid and accurate tool for the early diagnosis of PTB. The accuracy of diagnosis was superior compared with the SM and TB‐DNA. Moreover, Xpert is a quick and accurate method for the diagnosis of rifampicin‐resistant tuberculosis and can also provide more effective guidance for the treatment of PTB or multidrug‐resistant tuberculosis (MDR‐TB).

The composition of the lung microbiome differs between patients with dermatomyositis and rheumatoid arthritis associated with interstitial lung disease

Dermatomyositis and rheumatoid arthritis are inflammatory diseases that affect the skeletal muscles and joints, respectively. A common systemic complication of these diseases is interstitial lung disease (ILD), which leads to a poor prognosis and increased mortality. However, the mechanism for the initiation and development of ILD in patients with dermatomyositis is currently unknown. In the present study, we used 16S rRNA high‐throughput sequencing to profile the bacterial community composition of bronchoalveolar lavage fluid of patients with dermatomyositis associated with ILD (DM‐ILD; shortened to DM below), rheumatoid arthritis associated with ILD (RA‐ILD; shortened to RA below) and healthy controls (N) aiming to understand the differences in their lung microbiota and to predict gene function. We found that there were more operational taxonomic units (OTUs) in the lung microbiota of both RA and DM compared to N, although there was no significant difference in the number of OTUs between RA and DM. Similarly, the diversity in alphaproteobacteria differed between RA and DM compared to N, but not between RA and DM. The lung microbiota of RA, DM and N was mainly comprised of five phyla: Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria, with 10 dominant genera. Despite the similarity in microbiota composition, we also identified 41 OTUs of lung microbiota that differed among RA, DM and N. Additionally, linear discriminant analysis effect size and linear discriminant analysis genus scores confirmed that 31 microbial biomarkers were clearly distinguished among RA, DM and N. The functional and metabolic alterations of the lung microbiota among RA, DM and N were predicted using picrust, and differentially abundant KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways were identified. Research on the lung microbiota of patients with DM and RA may open new opportunities for developing biomarkers to identify high‐risk patients.

Bacterial infection in dogs with aspiration pneumonia at 2 tertiary referral practices

Background

In dogs, antimicrobial drugs are widely prescribed for aspiration pneumonia (AP) despite poor documentation of bacterial infection in AP (b‐AP) using bronchoalveolar lavage fluid (BALF) analysis. Interpretating discordant cytology and culture results is challenging, contributing to lack of a criterion standard, and highlighting differences between veterinary and human medical criteria for b‐AP.

Objectives

Determine how many dogs with AP had BALF collection and differences in diagnosis of b‐AP using veterinary vs human medical criteria. Report findings of noninvasive markers (e.g. fever, band neutrophilia, radiographic severity score) in dogs with and without b‐AP.

Animals

Retrospective cohort study of client‐owned dogs (n = 429) with AP at 2 university veterinary hospitals. Twenty‐four dogs met enrollment criteria.

Methods

Inclusion criteria were radiographic diagnosis of AP, ≥1 risk factor, CBC findings, and BALF cytology and culture results. Veterinary medical b‐AP criteria were cytology findings compatible with sepsis with or without positive culture, or cytology findings not consistent with sepsis and positive culture (≥1.7 × 10³ cfu/mL). Human medical b‐AP criteria required culture with ≥10⁴ cfu/mL or > 7% cells with intracellular bacteria on cytology.

Results

Only 24/429 dogs met all enrollment criteria; 379/429 dogs lacked BALF collection. Diagnosis of b‐AP differed using veterinary (79%) vs human (29%) medical criteria. Fever, band neutrophils and high radiographic scores were noted in dogs with and without b‐AP.

Conclusions and Clinical Importance

Lack of routine BALF collection hampers definitive recognition of bacterial infection in AP. Differences in dogs meeting veterinary vs human medical definitions for b‐AP and usefulness of noninvasive markers warrant further study to improve understanding of the role of bacteria in AP.

Diagnosis and treatment for a case of Legionella longbeachae severe pneumonia and literature review

As a type of Legionella bacteria, Legionella longbeachae bacteria can lead to very rare legionella disease case in China with clinical characteristics, such as no typical early clinical symptoms, strong toxicity, high mortality, and not easy to detect by conventional etiology. A case of severe pneumonia caused by Legionella longbeachae infection was confirmed by bronchoalveolar lavage fluid pathogen metagenomics, and the patient's condition was improved after targeted anti-infection treatment. At present, our understanding in Legionella longbeachae severe pneumonia is limited. The diagnosis and treatment process of the patient with severe pneumonia of Legionella longbeachaeis retrospectively analyzed and the relevant literature was reviewed to provide the experience for its future diagnosis and treatment.

Healthy versus inflamed lung environments differentially affect mesenchymal stromal cells

BACKGROUND

Despite increased interest in mesenchymal stromal cell (MSC)-based cell therapies for acute respiratory distress syndrome (ARDS), clinical investigations have not yet been successful and our understanding of the potential in vivo mechanisms of MSC actions in ARDS remains limited. ARDS is driven by an acute severe innate immune dysregulation, often characterised by inflammation, coagulation and cell injury. How this inflammatory microenvironment influences MSC functions remains to be determined.

AIM

The aim of this study was to comparatively assess how the inflammatory environment present in ARDS lungs versus the lung environment present in healthy volunteers alters MSC behaviour.

METHODS

Clinical-grade human bone marrow-derived MSCs (hMSCs) were exposed to bronchoalveolar lavage fluid (BALF) samples obtained from ARDS patients or from healthy volunteers. Following exposure, hMSCs and their conditioned media were evaluated for a broad panel of relevant properties, including viability, levels of expression of inflammatory cytokines, gene expression, cell surface human leukocyte antigen expression, and activation of coagulation and complement pathways.

RESULTS

Pro-inflammatory, pro-coagulant and major histocompatibility complex (self-recognition) related gene expression was markedly upregulated in hMSCs exposed ex vivo to BALF obtained from healthy volunteers. These changes were less apparent and often opposite in hMSCs exposed to ARDS BALF samples.

CONCLUSION

These data provide new insights into how hMSCs behave in healthy versus inflamed lung environments, and strongly suggest that the inflamed environment in ARDS induces hMSC responses that are potentially beneficial for cell survival and actions. This further highlights the need to understand how different disease environments affect hMSC functions.

Pathogen Metagenomics Reveals Distinct Lung Microbiota Signatures Between Bacteriologically Confirmed and Negative Tuberculosis Patients

Understanding the dynamics of lung microbiota in tuberculosis patients, especially those who cannot be confirmed bacteriologically in clinical practice, is imperative for accurate diagnosis and effective treatment. This study aims to characterize the distinct lung microbial features between bacteriologically confirmed and negative tuberculosis patients to understand the influence of microbiota on tuberculosis patients. We collected specimens of bronchoalveolar lavage fluid from 123 tuberculosis patients. Samples were subjected to metagenomic next-generation sequencing to reveal the lung microbial signatures. By combining conventional bacterial detection and metagenomic sequencing, 101/123 (82%) tuberculosis patients were bacteriologically confirmed. In addition to Mycobacterium tuberculosis, Staphylococcus aureus, Kluyveromyces lactis, and Pyricularia pennisetigena were also enriched in the bacteriological confirmation group. In contrast, Haemophilus parainfluenzae was enriched in the bacteriologically negative group. Besides, microbial interaction exhibits a different state between bacteriologically confirmed and negative tuberculosis patients. Mycobacterium tuberculosis was confirmed correlated with clinical characteristics such as albumin and chest cavities. Our study comprehensively demonstrates the correlation between unique features of lung microbial dynamics and the clinical characteristics of tuberculosis patients, suggesting the importance of studying the pulmonary microbiome in tuberculosis disease and providing new insights for future precision diagnosis and treatment.

Longitudinal Characterization of Cytokine Overproduction: A Case Report in Critically Ill COVID-19 Patients With Hyperinflammation in Bronchoalveolar Lavage

Objectives: The longitudinal characterization and risk of poor outcomes related to cytokine overproduction in critical coronavirus disease 2019 (COVID-19) patients with hyperinflammation in bronchoalveolar lavage requires further investigation. Methods: We enrolled two critically ill patients with comorbidities diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detected by RT-PCR during hospitalization. Clinical characteristics, longitudinal immunological, and biochemical parameters of each critical COVID-19 case were collected. Main Results: The clinical characteristics and laboratory results of each case demonstrated critical symptoms of COVID-19 with poor outcomes. Both nasopharyngeal swabs and bronchoalveolar lavage fluid (BALF) samples tested positive for SARS-CoV-2. Two patients received targeted treatments against pathogen infection and inflammation in addition to interventional therapies, except for Patient 2, who received an additional artificial liver system treatment. Hyperinflammation with a dominantly high level of IL-6 was observed in BALF samples from both critical cases with decreased T cell populations. High levels of cytokines and pathological parameters were successively maintained in Patient 1, but rapidly reduced at the late treatment stage in Patient 2. The outcome of Patient 1 is death, whereas the outcome of Patient 2 is recovery. Conclusions: This case report suggests that a high risk of poor outcomes was related to a heavily hyperinflammatory milieu in both the blood and lungs of critical COVID-19 patients. The artificial liver intervention on cytokines overproduction might be beneficial for the recovery of critical COVID-19 patients as a reliable therapy that can be coordinated with targeted treatments, which ought to be further tested in adequately designed and powered clinical trials.