Evaluation of the Cytokine Response Induced by Specific Allergen Immunotherapy in Patients with Vespa velutina Anaphylaxis.

INTRODUCTION: Changes in the cytokine profile from type 2 to type 1 together with the induction of regulatory cells are expected during hymenoptera venom immunotherapy (VIT). The present study was aimed to investigate the changes in type 1, type 2, and regulatory cytokines induced by a Vespula spp. VIT in patients with anaphylaxis to Vespa velutina. METHODS: Twenty consecutive patients with anaphylaxis due to Vespa velutina were treated with Vespula spp. VIT. Serum cytokines (IL-4, IL-5, IL-10, IL-13, and IFN-É£) were measured at baseline, 6, and 12 months after starting VIT. RESULTS: A significant increase in serum IFN-y was detected after 6 and 12 months of VIT. An increase in serum IL-10 and a decrease in IL-5 were observed after 12 months. IL-4 was undetectable all along the study, and an unexpected increase of IL-13 was present at 12 months of treatment. CONCLUSION: Vespula spp. VIT seems to be able to induce a shift to type 1 cytokine production measured through IFN-y levels and IL-10 production after, at least, 6 and 12 months of VIT, respectively.

Biomarker Profiles Associated with COVID-19 Severity and Mortality.

INTRODUCTION: The aim of this study was to analyze biomarkers that might predict the severity and progression of the SARS-CoV-2 infection, both in the acute phase and after recovery. METHODS: Unvaccinated patients infected with the original strain of COVID-19 requiring ward (Group 1, n = 48) or ICU (Group 2, n = 41) admission were included. At the time of admission (visit 1), a clinical history was acquired, and blood samples were obtained. One and six months after discharge from the hospital (visits 2 and 3, respectively), a clinical history, lung function tests, and blood samples were carried out. At visit 2, patients also underwent a chest CT scan. Different cytokines (IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, IL-17A, G-CSF, GM-CSF, IFN-É£, MCP-1, MIP-1ß, and TNF-α) and lung fibrosis biomarkers (YKL-40 and KL-6) were measured in blood samples obtained at visits 1, 2, and 3. RESULTS: At visit 1, IL-4, IL-5, and IL-6 levels were higher in Group 2 (p = 0.039, 0.011, and 0.045, respectively), and IL-17 and IL-8 levels were higher in Group 1 (p = 0.026 and 0.001, respectively). The number of patients in Groups 1 and 2 who died during hospitalization was 8 and 11, respectively. YKL-40 and KL-6 levels were higher in patients who died. Serum YKL-40 and KL-6 levels determined at visit 2 correlated negatively with FVC (p = 0.022 and p = 0.024, respectively) and FEV1 (p = 0.012 and p = 0.032, respectively) measured at visit 3. KL-6 levels also correlated negatively with the diffusing capacity of the lungs for carbon monoxide (DLCO, p = 0.001). CONCLUSIONS: Patients who required ICU admission had higher levels of Th2 cytokines, while patients admitted to the ward showed an innate immune response activation, with IL-8 release and Th1/Th17 lymphocyte contribution. Increased levels of YKL-40 and KL-6 were associated with mortality in COVID-19 patients.

Immunopathological Mechanisms of Bird-Related Hypersensitivity Pneumonitis.

Bird-related hypersensitivity pneumonitis (BRHP) is an interstitial lung disease induced by avian proteins. The immunopathological pathways involved in the disease are still unknown. This study assesses the cellular immune response and the cytokine pattern in a mouse model of BRHP. On days -3 and -1, mice were intraperitoneally sensitized with commercial pigeon serum (PS) or saline. Intranasal instillations with PS or saline were carried out on three consecutive days/week over either 3 weeks (Group 1) or 12 weeks (Group 2). Leukocyte and cytokine patterns in lung tissue and pulmonary inflammation in bronchoalveolar lavage (BAL) were analysed. Both groups presented increases in resident monocytes, interstitial macrophages and type 2 dendritic cells (DCs), but also reductions in inflammatory monocytes, alveolar macrophages and tolerogenic DCs compared with their control groups. Group 1 had increased levels of eosinophils and T cells with reductions in neutrophils and B cells, while Group 2 showed high levels of B cells. Both groups exhibited increases in Th1 and Th2 cytokines. Group 2 also showed increased levels of IL-23, a Th17 cytokine. Increased levels of neutrophils, eosinophils and lymphocytes were observed in BAL samples of both groups compared with controls. In the first stages of BRHP, there is a mixed Th1/Th2 immune response, while during the progression of the disease, although there is a Th1 response, the cytokine levels seem to indicate a switch towards a Th2/Th17 mixed response.

Analysis of Differentially Expressed MicroRNAs in Serum and Lung Tissues from Individuals with Severe Asthma Treated with Oral Glucocorticoids.

Nowadays, microRNAs (miRNAs) are increasingly used as biomarkers due to their potential contribution to the diagnosis and targeted treatment of a range of diseases. The aim of the study was to analyze the miRNA expression profiles in serum and lung tissue from patients with severe asthma treated with oral corticosteroids (OCS) and those without OCS treatment. For this purpose, serum and lung tissue miRNAs of OCS and non-OCS asthmatic individuals were evaluated by miRNAs-Seq, and subsequently miRNA validation was performed using RT-qPCR. Additionally, pathway enrichment analysis of deregulated miRNAs was conducted. We observed altered expression by the next-generation sequencing (NGS) of 11 miRNAs in serum, of which five (hsa-miR-148b-3p, hsa-miR-221-5p, hsa-miR-618, hsa-miR-941, and hsa-miR-769-5p) were validated by RT-qPCR, and three miRNAs in lung tissue (hsa-miR-144-3p, hsa-miR-144-5p, and hsa-miR-451a). The best multivariate logistic regression model to differentiate individuals with severe asthma, treated and untreated with OCS, was to combine the serum miRNAs hsa-miR-221-5p and hsa-miR-769-5p. Expression of hsa-miR-148b-3p and hsa-miR-221-5p correlated with FEV1/FVC (%) and these altered miRNAs act in key signaling pathways for asthma disease and the regulated expression of some genes (FOXO3, PTEN, and MAPK3) involved in these pathways. In conclusion, there are miRNA profiles differentially expressed in OCS-treated individuals with asthma and could be used as biomarkers of OCS treatment.

Multi-ancestry genome-wide association study of asthma exacerbations.

BACKGROUND: Asthma exacerbations are a serious public health concern due to high healthcare resource utilization, work/school productivity loss, impact on quality of life, and risk of mortality. The genetic basis of asthma exacerbations has been studied in several populations, but no prior study has performed a multi-ancestry meta-analysis of genome-wide association studies (meta-GWAS) for this trait. We aimed to identify common genetic loci associated with asthma exacerbations across diverse populations and to assess their functional role in regulating DNA methylation and gene expression. METHODS: A meta-GWAS of asthma exacerbations in 4989 Europeans, 2181 Hispanics/Latinos, 1250 Singaporean Chinese, and 972 African Americans analyzed 9.6 million genetic variants. Suggestively associated variants (p ≤ 5 × 10-5 ) were assessed for replication in 36,477 European and 1078 non-European asthma patients. Functional effects on DNA methylation were assessed in 595 Hispanic/Latino and African American asthma patients and in publicly available databases. The effect on gene expression was evaluated in silico. RESULTS: One hundred and twenty-six independent variants were suggestively associated with asthma exacerbations in the discovery phase. Two variants independently replicated: rs12091010 located at vascular cell adhesion molecule-1/exostosin like glycosyltransferase-2 (VCAM1/EXTL2) (discovery: odds ratio (ORT allele ) = 0.82, p = 9.05 × 10-6 and replication: ORT allele  = 0.89, p = 5.35 × 10-3 ) and rs943126 from pantothenate kinase 1 (PANK1) (discovery: ORC allele  = 0.85, p = 3.10 × 10-5 and replication: ORC allele  = 0.89, p = 1.30 × 10-2 ). Both variants regulate gene expression of genes where they locate and DNA methylation levels of nearby genes in whole blood. CONCLUSIONS: This multi-ancestry study revealed novel suggestive regulatory loci for asthma exacerbations located in genomic regions participating in inflammation and host defense.

iTRAQ-based proteomic analysis reveals potential serum biomarkers of allergic and nonallergic asthma.

BACKGROUND: Asthma is heterogeneous disease with different phenotypes, endotypes and severities. Definition of these subgroups requires the identification of biomarkers in biological samples, and serum proteomics is a useful and minimally invasive method for this purpose. Therefore, the aim of this study was to detect serum proteins whose abundance is distinctively associated with different asthma phenotypes (allergic vs nonallergic) or severities. METHODS: For each group of donors (32 healthy controls, 43 allergic rhinitis patients and 192 asthmatics with different phenotypes and severities), we generated two pools of sera that were analysed by a shotgun MS approach based on combinatorial peptide ligand libraries and iTRAQ-LC-MS/MS. RESULTS: MS analyses identified 18 proteins with a differential abundance. Functional/network study of these proteins identified key processes for asthma pathogenesis, such as complement activation, extracellular matrix organization, platelet activation and degranulation, or post-translational protein phosphorylation. Furthermore, our results highlighted an enrichment of the "Regulation of Insulin-like Growth Factor (IGF) transport and uptake by Insulin-like Growth Factor Binding Proteins (IGFBPs)" route in allergic asthma and the lectin pathway of complement activation in nonallergic asthma. Thus, several proteins (eg IGFALS, HSPG2, FCN2 or MASP1) displayed a differential abundance between the different groups of donors. Particularly, our results revealed IGFALS as a useful biomarker for moderate-severe allergic asthma. CONCLUSION: Our data suggest a set of serum biomarkers, especially IGFALS, capable of differentiating allergic from nonallergic asthma. These proteins reveal different pathophysiological mechanisms and may be useful in the future for diagnosis, prognosis or targeted therapy purposes.

Long-term outcomes in chronic hypersensitivity pneumonitis.

INTRODUCTION: The objective of this study was to analyze mortality, possible predictors of long-term survival, and health-related quality of life of a large chronic hypersensitivity pneumonitis (CHP) patient sample. METHODS: Longitudinal study in patients diagnosed with CHP during 2004-2013, followed for at least 1 year. Patients remaining alive and consenting to participate had a follow-up visit during 2015, including a complete pulmonary function study and the EuroQol-5D and Beck Depression and Anxiety Inventories. RESULTS: Out of the 160 patients finally included, 87 remained alive. Seventy-three had died or underwent lung transplantation at the time of the study with a median survival of 7.0 (4.4-14.5) years. A Cox proportional risk model showed that factors associated with lower survival were as follows: increased age, a low percentage of lymphocytes in bronchoalveolar lavage (BAL), a decreased transfer factor of the lung for carbonmonoxide (DLCO), presence of honeycomb in the high-resolution chest scan (HRCT), and the usual interstitial pneumonia (UIP) histologic pattern. At follow-up, all patients presented an EuroQol-5D score <0.8 and 21(50%) and 9(28.6%) subjects presented a probable anxiety and depressive syndrome, respectively. CONCLUSION: CHP is a severe disease with a bad mid-term prognosis. Lymphocyte values in BAL and DLCO values at baseline, presence of honeycomb in HRCT, and UIP histologic pattern were found to be predictors of survival. Early accurate diagnosis of the disease is fundamental for prompt initiation of antigen avoidance.

Immunological methods for diagnosis and monitoring of IgE-mediated allergy caused by industrial sensitizing agents (IMExAllergy).

Industrial sensitizing agents (allergens) in living and working environments play an important role in eliciting type 1 allergic disorders including asthma and allergic rhinitis. Successful management of allergic diseases necessitates identifying their specific causes (ie, identify the causative agent(s) and the route of contact to allergen: airborne, or skin contact) to avoid further exposure. Identification of sensitization by a sensitive and validated measurement of specific IgE is an important step in the diagnosis. However, only a limited number of environmental and occupational allergens are available on the market for use in sIgE testing. Accordingly, specific in-house testing by individual diagnostic and laboratory centers is often required. Currently, different immunological tests are in use at various diagnostic centers that often produce considerably divergent results, mostly due to lack of standardized allergen preparation and standardized procedures as well as inadequate quality control. Our review and meta-analysis exhibited satisfactory performance of sIgE detection test for most high molecular weight (HMW) allergens with a pooled sensitivity of 0.74 and specificity of 0.71. However, for low molecular weight (LMW) allergens, pooled sensitivity is generally lower (0.28) and specificity higher (0.89) than for HMW tests. Major recommendations based on the presented data include diagnostic use of sIgE to HMW allergens. A negative sIgE result for LMW agents does not exclude sensitization. In addition, the requirements for full transparency of the content of allergen preparations with details on standardization and quality control are underlined. Development of standard operating procedures for in-house sIgE assays, and clinical validation, centralized quality control and audits are emphasized. There is also a need for specialized laboratories to provide a custom service for the development of tests for the measurement of putative novel occupational allergens that are not commercially available.

Genetic variants with gene regulatory effects are associated with diisocyanate-induced asthma.

BACKGROUND: Isocyanates are major causes of occupational asthma, but susceptibility and mechanisms of diisocyanate-induced asthma (DA) remain uncertain. OBJECTIVE: The aim of this study was to identify DA-associated functional genetic variants through next-generation sequencing (NGS), bioinformatics, and functional assays. METHODS: NGS was performed in 91 workers with DA. Fourteen loci with known DA-associated single nucleotide polymorphisms (SNPs) were sequenced and compared with data from 238 unexposed subjects. Ranking of DA-associated SNPs based on their likelihood to affect gene regulatory mechanisms in the lung yielded 21 prioritized SNPs. Risk and nonrisk oligonucleotides were tested for binding of nuclear extracts from A549, BEAS-2B, and IMR-90 lung cell lines by using electrophoretic mobility shift assays. DNA constructs were cloned into a pGL3 promoter vector for luciferase gene reporter assays. RESULTS: NGS detected 130 risk variants associated with DA (3.1 × 10-6 to 6.21 × 10-4), 129 of which were located in noncoding regions. The 21 SNPs prioritized by using functional genomic data sets were in or proximal to 5 genes: cadherin 17 (CDH17; n = 10), activating transcription factor 3 (ATF3; n = 7), family with sequence similarity, member A (FAM71A; n = 2), tachykinin receptor 1 (TACR1; n = 1), and zinc finger and BTB domain-containing protein 16 (ZBTB16; n = 1). Electrophoretic mobility shift assays detected allele-dependent nuclear protein binding in A549 cells for 8 of 21 variants. In the luciferase assay 4 of the 21 SNPs exhibited allele-dependent changes in gene expression. DNA affinity precipitation and mass spectroscopy of rs147978008 revealed allele-dependent binding of H1 histones, which was confirmed by using Western blotting. CONCLUSIONS: We identified 5 DA-associated potential regulatory SNPs. Four variants exhibited effects on gene regulation (ATF rs11571537, CDH17 rs2446824 and rs2513789, and TACR1 rs2287231). A fifth variant (FAM71A rs147978008) showed nonrisk allele preferential binding to H1 histones. These results demonstrate that many DA-associated genetic variants likely act by modulating gene regulation.

BALF cytokines in different phenotypes of chronic lung allograft dysfunction in lung transplant patients.

The long-term success of lung transplantation (LT) is limited by chronic lung allograft dysfunction (CLAD). Different phenotypes of CLAD have been described, such as bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). The purpose of this study was to investigate the levels of cytokines and chemokines in bronchoalveolar lavage fluid (BALF) as markers of these CLAD phenotypes. BALF was collected from 51 recipients who underwent (bilateral and unilateral) LT. The study population was divided into three groups: stable (ST), BOS, and RAS. Levels of interleukin (IL)-4, IL-5, IL-6, IL-10, IL-13, tumor necrosis factor alpha (TNF-α), interferon-gamma (IFN-γ), and granulocyte-macrophage colony-stimulating factor (GM-CSF) were measured using the multiplex technology. BALF neutrophilia medians were higher in BOS (38%) and RAS (30%) than in ST (8%) (P=.008; P=.012). Regarding BALF cytokines, BOS and RAS patients showed higher levels of INF-γ than ST (P=.02; P=.008). Only IL-5 presented significant differences between BOS and RAS (P=.001). BALF neutrophilia is as a marker for both CLAD phenotypes, BOS and RAS, and IL-5 seems to be a potential biomarker for the RAS phenotype.

Specific inhalation challenge: the relationship between response, clinical variables and lung function.

INTRODUCTION: The specific inhalation challenge (SIC) is considered the gold standard for the diagnosis of occupational asthma (OA). However, its use is not standardised, and the intensity of exposure is regulated empirically. The aim of this study was to identify clinical variables and/or pulmonary function variables able to predict the scale of patients' response to SIC. MATERIAL AND METHODS: All patients who underwent SIC at our centre between 2005 and 2013 were studied. Anthropometric characteristics, atopic status, type of causal agent, latency times, pulmonary function tests and SIC results were analysed. RESULTS: Two hundred and one patients (51% men) were assessed, of whom 86 (43%) had positive SIC. In the patients with positive results, 29 (34%) were exposed to high molecular weight (HMW) agents and 57 (64%) to low molecular weight (LMW) agents. Patients with a positive SIC exposed to HMW agents had a higher fall in FEV1 after SIC compared with those exposed to LMW agents (p=0.036). The type of asthmatic reaction after SIC also differed between the groups (p=0.020). The logistic regression analysis showed that patients with a higher PC20 before SIC were less likely to have severe decreases in FEV1 after SIC after adjusting for potential confounders (OR=0.771, 95% CI 0.618 to 0.961, p=0.021). CONCLUSIONS: The scale of the response to SIC is influenced mainly by the degree of bronchial hyper-responsiveness, regardless of whether the causative agent is HMW or LMW, or whether the response is early or late.

Hypersensitivity Pneumonitis: Challenges in Diagnosis and Management, Avoiding Surgical Lung Biopsy.

This review presents an update of the currently available information related to hypersensitivity pneumonitis, with a particular focus on the contribution of several techniques in the diagnosis of this condition. The methods discussed include proper elaboration of a complete medical history, targeted auscultation, detection of specific immunoglobulin G antibodies against the most common antigens causing this disease, skin tests, antigen-specific lymphocyte activation assays, bronchoalveolar lavage, and cryobiopsy. Special emphasis is placed on the relevant contribution of specific inhalation challenge (bronchial challenge test). Surgical lung biopsy is presented as the ultimate recourse, to be used when the diagnosis cannot be reached through the other methods covered.

Usefulness of noninvasive methods for the study of bronchial inflammation in the control of patients with asthma.

Bronchial asthma is one of the most prevalent respiratory conditions. Although it is defined as an inflammatory disease, the current guidelines for both diagnosis and follow-up of patients are based only on clinical and lung function parameters. Current research is focused on finding markers that can accurately predict future risk, and on assessing the ability of these markers to guide medical treatment and thus improve prognosis. The use of noninvasive methods to study airway inflammation is gaining increasing support. The study of eosinophils in induced sputum has proved useful for the diagnosis of asthma; however, its clinical implementation is complex. Some studies have shown that the measurement of exhaled nitric oxide (FeNO) may also be useful to establish disease phenotypes and improve control. Others have found that the measurement of pH and certain markers of oxidative stress, cytokines and prostanoids in exhaled breath condensate (EBC) may also be useful as well as the measurement of the temperature of exhaled breath and the analysis of volatile organic compounds (VOCs). In conclusion, since asthma is an inflammatory disease, it seems appropriate to try to control it through the study of airway inflammation using noninvasive methods. In this regard, the analysis of induced sputum cells has proved very useful, although the clinical implementation of this technique seems difficult. Other techniques such as temperature measurement, the analysis of FeNO, the analysis of the VOCs in exhaled breath, or the study of certain biomarkers in EBC require further study in order to determine their clinical applicability.

Diagnostic yield of specific inhalation challenge in hypersensitivity pneumonitis.

Reliable methods are needed to diagnose hypersensitivity pneumonitis. The aim of the study was to establish the diagnostic yield of specific inhalation challenge (SIC) in patients with hypersensitivity pneumonitis. All patients with suspected hypersensitivity pneumonitis in whom SIC was performed (n=113) were included. SIC was considered positive when patients showed a decrease of >15% in forced vital capacity (FVC) or >20% in diffusing capacity of the lung for carbon dioxide, or a decrease of 10% to 15% in FVC accompanied by a temperature increase of 0.5°C within 24 h of inhalation of the antigen. SIC was positive to the agents tested in 68 patients: 64 received a diagnosis of hypersensitivity pneumonitis and SIC results were considered false-positive in the remaining four patients. In the SIC-negative group (n=45), 24 patients received a diagnosis of hypersensitivity pneumonitis and SIC results were considered false-negative, and 21 patients were diagnosed with other respiratory diseases. The sensitivity and specificity of the test were 72.7% and 84%, respectively. Having hypersensitivity pneumonitis caused by an antigen other than birds or fungi predicted a false-negative result (p=0.001). In hypersensitivity pneumonitis, positive SIC testing virtually confirms the diagnosis, whereas negative testing does not rule it out, especially when the antigenic sources are not birds or fungi.

Assessing the efficacy of immunotherapy with a glutaraldehyde-modified house dust mite extract in children by monitoring changes in clinical parameters and inflammatory markers in exhaled breath.

INTRODUCTION: The aim of this study was to evaluate the effectiveness of specific immunotherapy (SIT) management with allergoids in children with allergic asthma by monitoring changes in clinical parameters and inflammatory markers in exhaled breath. METHODS: The study population included 43 patients (24 males) of 6-14 years of age, who had allergic asthma and were sensitized to mites. Twenty-three individuals were treated with subcutaneous SIT (PURETHAL® Mites, HAL Allergy) for 8 months, i.e. the SIT group, and 20 were given medication to treat symptoms only, i.e. the control group. Before treatment and after 4 and 8 months, several clinical parameters, the levels of exhaled nitric oxide and the pH of exhaled breath condensate (EBC) were determined. RESULTS: The SIT group presented with an improvement in asthma classification, a reduction in maintenance drug therapy and improved scores on the quality-of-life questionnaire. These changes were not observed in the control group. Both groups presented significant decreases in EBC pH values at 4 and 8 months after treatment compared to at baseline. However, analysis of the variable 'ratio' showed an increase in the EBC pH values after 8 months of treatment in the SIT group compared with the values at 4 months. CONCLUSIONS: SIT with standardized mite extract reduces asthma symptoms in children. A decrease in EBC pH values was observed in both groups, although the SIT group presented a tendency of recovered values after 8 months. Future studies of EBC pH monitoring in the longer term are needed to determine the effectiveness of this marker.

Bronchial inflammation in hypersensitivity pneumonitis after antigen-specific inhalation challenge.

BACKGROUND AND OBJECTIVE: The aim of this study is to compare the inflammatory profile before and after specific inhalation challenge (SIC) in induced sputum from patients with hypersensitivity pneumonitis (HP) and to investigate whether different causal antigens define the resulting profile. METHODS: A prospective study was conducted in 27 patients with HP: 15 patients due to exposure to birds (BHP) and 12 due to exposure to fungi (FHP), confirmed by SIC. Induced sputum was obtained before and/or 24 h after SIC. Cell types were determined by differential cell count using optical microscopy. Interferon-γ, interleukin (IL)-12p70, IL-2, IL-10, IL-8, IL-6, IL-4, IL-5, IL-1ß, tumour necrosis factor (TNF)-α and TNF-ß levels were measured in the supernatants. RESULTS: Following SIC, higher sputum neutrophilia levels (P = 0.048) and an increase in IL-8 levels (P = 0.017) were found in patients with FHP than in those with BHP. FHP patients also showed increased IL-1ß, IL12-p70 and IL5 levels (P = 0.011, P = 0.036 and P = 0.018, respectively) after SIC. In BHP, a trend towards increases in sputum eosinophils and TH2 cytokines (IL4, IL5) was seen following SIC (P = 0.059, P = 0.068 and P = 0.075 respectively). CONCLUSIONS: This study shows that bronchial inflammation is present in patients with HP evidenced by increases in sputum neutrophils and eosinophils following exposure to the offending antigen during SIC.

Acquired tracheomalacia due to SARS-CoV-2 pneumonia.

INTRODUCTION: Several studies mentioned parenchymal findings after SARS-CoV-2 pneumonia, but few studies have mentioned alterations in the airways. The aim of this study was to estimate the prevalence of tracheomalacia and to analyse the clinical characteristics in a cohort of patients with SARS-CoV-2. METHODS: The study population consisted of all patients with SARS-CoV-2 admitted a hospital serving a population of 500 000 inhabitants. Patients were visited between 2 and 6 months after hospital discharge. In this visit, all patients were subjected to an exhaustive clinical questionnaire and underwent clinical examination, pulmonary function tests and chest CT. RESULTS: From February 2020 to August 2021, 1920 patients were included in the cohort and tracheomalacia was observed in 15 (0.8%) on expiratory HRCT imaging. All patients with tracheomalacia also presented ground glass opacities in the CT scan and 12 patients had airway sequelae. CONCLUSIONS: Tracheomalacia is an exceptional sequela of SARS-CoV-2 survivors.

Immunological Effects of Diesel Particles in a Murine Model of Healthy Mice.

Introduction: Exposure to environmental pollutants such as diesel exhaust particles (DEP) increases the risk of respiratory disease exacerbation. However, the possible effects of these particles on the general population remain poorly understood. The present study aimed to assess the immunomodulatory and inflammatory effects of the inhalation of DEP in a model of healthy mice undergoing short-, mid- and long-term exposure. Materials and Methods: BALB/c ByJ mice were randomly divided into five experimental groups. The control group received three intranasal instillations of saline over 8 days while the other four groups received intranasal instillations of 150 µg of DEP 3 days per week for 8, 17, 26, and 53 days. Lung function assessment and flow cytometry were performed. Results: In lung tissue, intranasal exposure to DEP decreased total monocytes (p < 0.015 in all groups). At 26 days, a reduction in inflammatory monocytes and an increase in resident monocytes were observed, p = 0.001 and 0.0001, respectively. Eosinophils and neutrophils decreased at 26 days (p = 0.017 and p = 0.041, respectively). The intranasal challenges of DEP increased the total population of dendritic cells (DC) at 26 and 53 days (p = 0.017 and p = 0.022, respectively) and decreased the total and alveolar populations of macrophages (p < 0.003 for all groups compared to control), while interstitial macrophage populations increased over the time period (p = 0.0001 for all groups compared to control). Conclusions: Continuous DEP exposure triggers immune mechanisms that predispose healthy individuals to a pro-inflammatory and hyper-reactive microenvironment. This mouse model provides evidence of the capacity of DEP to increase DC, interstitial macrophages, and resident monocytes.

The Impact of the Reduction in Environmental Pollution during COVID-19 Lockdown on Healthy Individuals.

The lockdown imposed to combat the COVID-19 pandemic produced a historic fall in air pollution in cities like Barcelona. This exceptional situation offered a unique context in which to examine the effects of air pollutants on human health. The present study aims to determine and compare the oxidative stress biomarkers Th1/Th2 and inflammatory-related cytokines in healthy individuals first during lockdown and then six months after the easing of the restrictions on mobility. A prospective study of a representative sample of 58 healthy, non-smoking adults was carried out. During lockdown and six months post-easing of restrictions, blood samples were drawn to measure the percentage of eosinophils, levels of Th1/Th2 and inflammatory-related cytokines assessed by a multiplex assay (BioRad Laboratories S.A., Marnes-la-Coquette, France), and levels of 8-isoprostane, glutathione peroxidase activity, and myeloperoxidase (Cayman Chemical Co., Ann Arbor, MI, USA), to assess their value as biomarkers of oxidative stress. Six months after easing mobility restrictions, increases in the levels of 8-isoprostane (p < 0.0001), IL-1ß (p = 0.0013), IL-1ra (p = 0.0110), IL-4 (p < 0.0001), IL-13 (p < 0.0001), G-CSF (p = 0.0007), and CCL3 (p < 0.0001) were recorded, along with reductions in glutathione peroxidase (p < 0.0001), IFN-γ (p = 0.0145), TNFα (p < 0.0001), IP-10 (p < 0.0001), IL-2 (p < 0.0001), IL-7 (p < 0.0001), basic FGF (p < 0.0001), CCL4 (p < 0.0001), and CCL5 (p < 0.0001). No significant differences were observed in the rest of the biomarkers analyzed. The reduction in environmental pollution during the COVID-19 lockdown significantly lowered the levels of oxidative stress, systemic inflammation, and Th2-related cytokines in healthy people.