Small Animal Models of Respiratory Viral Infection Related to Asthma

Pulmonary adaptation to repeated poly(I:C) exposure is impaired in asthmatic mice: an observational study

BACKGROUND

While asthma exacerbations remain a major challenge in patient management, few animal models exist to explore the underlying mechanisms. Here, we established an animal model of asthma that can be used to study pathophysiological mechanisms and therapeutic strategies on asthma exacerbation.

METHODS

Female BALB/c mice were sensitized and exposed to PBS or Dermatophagoides pteronyssinus (DerP) extract for 11 weeks. Asthmatic phenotype was assessed through lung inflammation, bronchial hyperresponsiveness and bronchial smooth muscle remodeling. Asthmatic and control mice were exposed once or three times to poly(I:C) to simulate virus-induced inflammation.

RESULTS

Fourteen days after exposure to DerP, asthmatic mice showed resolution of inflammation with sustained bronchial hyperresponsiveness and bronchial smooth muscle remodeling compared to control. At this stage, when mice were subjected to a single exposure to poly(I:C), control and asthmatic mice were characterized by a significant increase in neutrophilic inflammation and bronchial hyperresponsiveness. When mice were repeatedly exposed to poly(I:C), control mice showed a significant decrease in neutrophilic inflammation and bronchial hyperresponsiveness, while asthmatic mice experienced worsening of these outcomes.

CONCLUSIONS

This observational study report an asthmatic mouse model that can undergo exacerbation after repeated exposure to poly(I:C). Our findings on pulmonary adaptation in control mice may also pave the way for further research into the mechanism of adaptation that may be impaired in asthma and raise the question of whether asthma exacerbation may be a loss of adaptation.

Adjuvant-independent airway sensitization and infection mouse models leading to allergic asthma

Asthma is a chronic respiratory disease of global importance. Mouse models of allergic asthma have been instrumental in advancing research and novel therapeutic strategies for patients. The application of relevant allergens and physiological routes of exposure in such models has led to valuable insights into the complexities of asthma onset and development as well as key disease mechanisms. Furthermore, environmental microbial exposures and infections have been shown to play a fundamental part in asthma pathogenesis and alter disease outcome. In this review, we delve into physiological mouse models of allergic asthma and explore literature reports on most significant interplays between microbial infections and asthma development with relevance to human disease.

Meeting Ferret Enrichment Needs in Infectious Disease Laboratory Settings

Environmental enrichment is a necessary component of all research vivarium settings. However, appropriate enrichment decisions vary greatly depending on the species involved and the research use of the animals. The increasing use of ferrets in research settings-notably for modeling the pathogenicity and transmissibility of viral pathogens that require containment in ABSL-2 to -4 environments-presents a particular challenge for veterinary and research staff to ensure that enrichment needs for these animals are met consistently. Here, we discuss the species-specific enrichment needs of ferrets, enrichment considerations for ferrets housed in research settings, and the challenges and importance of providing appropriate enrichment during experimentation, including when ferrets are housed in high-containment facilities. This article is organized to support the easy availability of information that will facilitate the design and implementation of optimal environmental enrichment for ferrets used in diverse research efforts in vivarium settings.

Update on virus-induced asthma exacerbations

INTRODUCTION

Viral infections are common triggers for asthma exacerbation. Subjects with asthma are more susceptible to viral infections and develop more severe or long-lasting lower respiratory tract symptoms than healthy individuals owing to impaired immune responses. Of the many viruses associated with asthma exacerbation, rhinovirus (RV) is the most frequently identified virus in both adults and children.

AREAS COVERED

We reviewed epidemiological and clinical links and mechanistic studies on virus-associated asthma exacerbations. We included sections on severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), the latest evidence of coronavirus disease 2019 (COVID-19) in asthma patients, and past and future searches for therapeutic and prevention targets.

EXPERT OPINION

Early treatment or prevention of viral infections might significantly reduce the rate of asthma exacerbation, which is one of the key points of disease management. Although it is hypothetically possible nowadays to interfere with every step of the infectious cycle of respiratory tract viruses, vaccination development has provided some of the most encouraging results. Future research should proceed toward the development of a wider spectrum of vaccines to achieve a better quality of life for patients with asthma and to reduce the economic burden on the healthcare system.

Tingli Dazao Xiefei Decoction ameliorates asthma in vivo and in vitro from lung to intestine by modifying NO-CO metabolic disorder mediated inflammation, immune imbalance, cellular barrier damage, oxidative stress and intestinal bacterial disorders

ETHNOPHARMACOLOGICAL RELEVANCE

Asthma is a chronic airway inflammatory disease. Current treatment of mainstream medications has significant side effects. There is growing evidence that the refractoriness of asthma is closely related to common changes in the lung and intestine. The lungs and intestines, as sites of frequent gas exchange in the body, are widely populated with gas signaling molecules NO and CO, which constitute NO-CO metabolism and may be relevant to the pathogenesis of asthma in the lung and intestine. The Chinese herbal formula Tingli Dazao Xiefei Decoction (TD) is commonly used in clinical practice to treat asthma with good efficacy, but there are few systematic evaluations of the efficacy of asthma on NO-CO metabolism, and the mode of action of its improving effect on the lung and intestine is unclear.

AIM OF THE STUDY

To investigate the effect of TD on the lung and intestine of asthmatic rats based on NO-CO metabolism.

MATERIALS AND METHODS

In vivo, we established a rat asthma model by intraperitoneal injection of sensitizing solution with OVA atomization, followed by intervention by gavage administration of TD. We simultaneously examined alterations in basal function, pathology, NO-CO metabolism, inflammation and immune cell homeostasis in the lungs and intestines of asthmatic rats, and detected changes in intestinal flora by macrogenome sequencing technology, with a view to multi-angle evaluation of the treatment effects of TD on asthmatic rats. In vitro, lung cells BEAS-2B and intestinal cells NCM-460 were used to establish a model of lung injury causing intestinal injury using LPS and co-culture chambers, and lung cells or intestinal cells TD-containing serum was administered to intervene. Changes in inflammatory, NO-CO metabolism-related, cell barrier-related and oxidative stress indicators were measured in lung cells and intestinal cells to evaluate TD on intestinal injury by way of amelioration and in-depth mechanism.

RESULTS

In vivo, our results showed significant basal functional impairment in the lung and intestine of asthmatic rats, and an inflammatory response, immune cell imbalance and intestinal flora disturbance elicited by NO-CO metabolic disorders were observed (P < 0.05 or 0.01). The administration of TD was shown to deliver a multidimensional amelioration of the impairment induced by NO-CO metabolic disorders (P < 0.05 or 0.01). In vitro, the results showed that LPS-induced lung cells BEAS-2B injury could cause NO-CO metabolic disorder-induced inflammatory response, cell permeability damage and oxidative stress damage in intestinal cells NCM-460 (P < 0.01). The ameliorative effect on intestinal cells NCM-460 could only be exerted when TD-containing serum interfered with lung cells BEAS-2B (P < 0.01), suggesting that the intestinal ameliorative effect of TD may be exerted indirectly through the lung.

CONCLUSION

TD can ameliorate NO-CO metabolism in the lung and thus achieve the indirectly amelioration of NO-CO metabolism in the intestine, ultimately achieving co-regulation of lung and intestinal inflammation, immune imbalance, cellular barrier damage, oxidative stress and intestinal bacterial disorders in asthma in vivo and in vitro. Targeting lung and intestinal NO-CO metabolic disorders in asthma may be a new therapeutic idea and strategy for asthma.

From animal studies into clinical trials: the relevance of animal models to develop vaccines and therapies to reduce disease severity and prevent hRSV infection

INTRODUCTION

Human respiratory syncytial virus (hRSV) is an important cause of lower respiratory tract infections in the pediatric and the geriatric population worldwide. There is a substantial economic burden resulting from hRSV disease during winter. Although no vaccines have been approved for human use, prophylactic therapies are available for high-risk populations. Choosing the proper animal models to evaluate different vaccine prototypes or pharmacological treatments is essential for developing efficient therapies against hRSV.

AREAS COVERED

This article describes the relevance of using different animal models to evaluate the effect of antiviral drugs, pharmacological molecules, vaccine prototypes, and antibodies in the protection against hRSV. The animal models covered are rodents, mustelids, bovines, and nonhuman primates. Animals included were chosen based on the available literature and their role in the development of the drugs discussed in this manuscript.

EXPERT OPINION

Choosing the correct animal model is critical for exploring and testing treatments that could decrease the impact of hRSV in high-risk populations. Mice will continue to be the most used preclinical model to evaluate this. However, researchers must also explore the use of other models such as nonhuman primates, as they are more similar to humans, prior to escalating into clinical trials.

Modulation of Alveolar Macrophages by Postimmunobiotics: Impact on TLR3-Mediated Antiviral Respiratory Immunity

Beneficial microbes with immunomodulatory capacities (immunobiotics) and their non-viable forms (postimmunobiotics) could be effectively utilized in formulations towards the prevention of respiratory viral infections. In this study, novel immunobiotic strains with the ability to increase antiviral immunity in porcine alveolar macrophages were selected from a library of Lactobacillus gasseri. Postimmunobiotics derived from the most remarkable strains were also evaluated in their capacity to modulate the immune response triggered by Toll-like receptor 3 (TLR3) in alveolar macrophages and to differentially regulate TLR3-mediated antiviral respiratory immunity in infant mice. We provide evidence that porcine alveolar macrophages (3D4/31 cells) are a useful in vitro tool for the screening of new antiviral immunobiotics and postimmunobiotics by assessing their ability to modulate the expression IFN-β, IFN-λ1, RNAseL, Mx2, and IL-6, which can be used as prospective biomarkers. We also demonstrate that the postimmunobiotics derived from the Lactobacillus gasseri TMT36, TMT39 and TMT40 (HK36, HK39 or HK40) strains modulate the innate antiviral immune response of alveolar macrophages and reduce lung inflammatory damage triggered by TLR3 activation in vivo. Although our findings should be deepened and expanded, the results of the present work provide a scientific rationale for the use of nasally administered HK36, HK39 or HK40 to beneficially modulate TLR3-triggerd respiratory innate immune response.

Animal Models of Enterovirus D68 Infection and Disease

Human enterovirus D68 (EV-D68) is a globally reemerging respiratory pathogen that is associated with the development of acute flaccid myelitis (AFM) in children. Currently, there are no approved vaccines or treatments for EV-D68 infection, and there is a paucity of data related to the virus and host-specific factors that predict disease severity and progression to the neurologic syndrome. EV-D68 infection of various animal models has served as an important platform for characterization and comparison of disease pathogenesis between historic and contemporary isolates. Still, there are significant gaps in our knowledge of EV-D68 pathogenesis that constrain the development and evaluation of targeted vaccines and antiviral therapies. Continued refinement and characterization of animal models that faithfully reproduce key elements of EV-D68 infection and disease is essential for ensuring public health preparedness for future EV-D68 outbreaks.

Childhood asthma- pathogenesis and phenotypes

In the pathogenesis of asthma in children there is a pivotal role for a type 2 inflammatory response to early life exposures or events. Interactions between infections, atopy, genetic susceptibility, and environmental exposures (such as farmyard environment, air pollution, tobacco smoke exposure) influence the development of wheezing illness and the risk for progression to asthma. The immune system, lung function and the microbiome in gut and airways develop in parallel and dysbiosis of the microbiome may be a critical factor in asthma development. Increased infant weight gain and preterm birth are other risk factors for development of asthma and reduced lung function. The complex interplay between these factors explains the heterogeneity of asthma in children. Subgroups of patients can be identified as phenotypes based on clinical parameters, or endotypes, based on a specific pathophysiological mechanism. Paediatric asthma phenotypes and endotypes may ultimately help to improve diagnosis of asthma, prediction of asthma development and treatment of individual children, based on clinical, temporal, developmental or inflammatory characteristics. Unbiased, data-driven clustering, using a multidimensional or systems biology approach may be needed to better define phenotypes. The present knowledge on inflammatory phenotypes of childhood asthma has now been successfully applied in the treatment with biologicals of children with severe therapy resistant asthma, and it is to be expected that more personalized treatment options may become available.

Indoleamine 2,3-Dioxygenase in Hematopoietic Stem Cell-Derived Cells Suppresses Rhinovirus-Induced Neutrophilic Airway Inflammation by Regulating Th1- and Th17-Type Responses

Asthma exacerbations are a major cause of intractable morbidity, increases in health care costs, and a greater progressive loss of lung function. Asthma exacerbations are most commonly triggered by respiratory viral infections, particularly with human rhinovirus (hRV). Respiratory viral infections are believed to affect the expression of indoleamine 2,3-dioxygenase (IDO), a limiting enzyme in tryptophan catabolism, which is presumed to alter asthmatic airway inflammation. Here, we explored the detailed role of IDO in the progression of asthma exacerbations using a mouse model for asthma exacerbation caused by hRV infection. Our results reveal that IDO is required to prevent neutrophilic inflammation in the course of asthma exacerbation caused by an hRV infection, as corroborated by markedly enhanced Th17- and Th1-type neutrophilia in the airways of IDO-deficient mice. This neutrophilia was closely associated with disrupted expression of tight junctions and enhanced expression of inflammasome-related molecules and mucin-inducing genes. In addition, IDO ablation enhanced allergen-specific Th17- and Th1-biased CD4⁺ T-cell responses following hRV infection. The role of IDO in attenuating Th17- and Th1-type neutrophilic airway inflammation became more apparent in chronic asthma exacerbations after repeated allergen exposures and hRV infections. Furthermore, IDO enzymatic induction in leukocytes derived from the hematopoietic stem cell (HSC) lineage appeared to play a dominant role in attenuating Th17- and Th1-type neutrophilic inflammation in the airway following hRV infection. Therefore, IDO activity in HSC-derived leukocytes is required to regulate Th17- and Th1-type neutrophilic inflammation in the airway during asthma exacerbations caused by hRV infections.

Organoid engineering with microfluidics and biomaterials for liver, lung disease, and cancer modeling

As life expectancy improves and the number of people suffering from various diseases increases, the need for developing effective personalized disease models is rapidly rising. The development of organoid technology has led to better recapitulation of the in vivo environment of organs, and can overcome the constraints of existing disease models. However, for more precise disease modeling, engineering approaches such as microfluidics and biomaterials, that aid in mimicking human physiology, need to be integrated with the organoid models. In this review, we introduce key elements for disease modeling and recent engineering advances using both liver and lung organoids. Due to the importance of personalized medicine, we also emphasize patient-derived cancer organoid models and their engineering approaches. These organoid-based disease models combined with microfluidics, biomaterials, and co-culture systems will provide a powerful research platform for understanding disease mechanisms and developing precision medicine; enabling preclinical drug screening and drug development. STATEMENT OF SIGNIFICANCE: The development of organoid technology has led to better recapitulation of the in vivo environment of organs, and can overcome the constraints of existing disease models. However, for more precise disease modeling, engineering approaches such as microfluidics and biomaterials, that aid in mimicking human physiology, need to be integrated with the organoid models. In this review, we introduce liver, lung, and cancer organoids integrated with various engineering approaches as a novel platform for personalized disease modeling. These engineered organoid-based disease models will provide a powerful research platform for understanding disease mechanisms and developing precision medicine.

Viral and Bacterial Co-Infections in the Lungs: Dangerous Liaisons

Respiratory tract infections constitute a significant public health problem, with a therapeutic arsenal that remains relatively limited and that is threatened by the emergence of antiviral and/or antibiotic resistance. Viral–bacterial co-infections are very often associated with the severity of these respiratory infections and have been explored mainly in the context of bacterial superinfections following primary influenza infection. This review summarizes our current knowledge of the mechanisms underlying these co-infections between respiratory viruses (influenza viruses, RSV, and SARS-CoV-2) and bacteria, at both the physiological and immunological levels. This review also explores the importance of the microbiome and the pathological context in the evolution of these respiratory tract co-infections and presents the different in vitro and in vivo experimental models available. A better understanding of the complex functional interactions between viruses/bacteria and host cells will allow the development of new, specific, and more effective diagnostic and therapeutic approaches.

Neutralization of IL-33 modifies the type 2 and type 3 inflammatory signature of viral induced asthma exacerbation

Background

Respiratory viral infections are one of the leading causes of need for emergency care and hospitalizations in asthmatic individuals, and airway-secreted cytokines are released within hours of viral infection to initiate these exacerbations. IL-33, specifically, contributes to these allergic exacerbations by amplifying type 2 inflammation. We hypothesized that blocking IL-33 in RSV-induced exacerbation would significantly reduce allergic inflammation.

Methods

Sensitized BALB/c mice were challenged with aerosolized ovalbumin (OVA) to establish allergic inflammation, followed by RSV-A2 infection to yield four treatment groups: saline only (Saline), RSV-infected alone (RSV), OVA alone (OVA), and OVA-treated with RSV infection (OVA-RSV). Lung outcomes included lung mRNA and protein markers of allergic inflammation, histology for mucus cell metaplasia and lung immune cell influx by cytospin and flow cytometry.

Results

While thymic stromal lymphopoietin (TSLP) and IL-33 were detected 6 h after RSV infection in the OVA-RSV mice, IL-23 protein was uniquely upregulated in RSV-infected mice alone. OVA-RSV animals varied from RSV- or OVA-treated mice as they had increased lung eosinophils, neutrophils, group 2 innate lymphoid cells (ILC2) and group 3 innate lymphoid cells (ILC3) detectable as early as 6 h after RSV infection. Neutralized IL-33 significantly reduced ILC2 and eosinophils, and the prototypical allergic proteins, IL-5, IL-13, CCL17 and CCL22 in OVA-RSV mice. Numbers of neutrophils and ILC3 were also reduced with anti-IL-33 treatment in both RSV and OVA-RSV treated animals as well.

Conclusions

Taken together, our findings indicate a broad reduction in allergic-proinflammatory events mediated by IL-33 neutralization in RSV-induced asthma exacerbation.

Role of ILC2 in Viral-Induced Lung Pathogenesis

Innate lymphoid type-2 cells (ILC2) are a population of innate cells of lymphoid origin that are known to drive strong Type 2 immunity. ILC2 play a key role in lung homeostasis, repair/remodeling of lung structures following injury, and initiation of inflammation as well as more complex roles during the immune response, including the transition from innate to adaptive immunity. Remarkably, dysregulation of this single population has been linked with chronic lung pathologies, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrotic diseases (IPF). Furthermore, ILC2 have been shown to increase following early-life respiratory viral infections, such as respiratory syncytial virus (RSV) and rhinovirus (RV), that may lead to long-term alterations of the lung environment. The detrimental roles of increased ILC2 following these infections may include pathogenic chronic inflammation and/or alterations of the structural, repair, and even developmental processes of the lung. Respiratory viral infections in older adults and patients with established chronic pulmonary diseases often lead to exacerbated responses, likely due to previous exposures that leave the lung in a dysregulated functional and structural state. This review will focus on the role of ILC2 during respiratory viral exposures and their effects on the induction and regulation of lung pathogenesis. We aim to provide insight into ILC2-driven mechanisms that may enhance lung-associated diseases throughout life. Understanding these mechanisms will help identify better treatment options to limit not only viral infection severity but also protect against the development and/or exacerbation of other lung pathologies linked to severe respiratory viral infections.

Clinical characteristics of 182 pediatric COVID-19 patients with different severities and allergic status

Background

The pandemic of coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection has made widespread impact recently. We aim to investigate the clinical characteristics of COVID‐19 children with different severities and allergic status.

Methods

Data extracted from the electronic medical records, including demographics, clinical manifestations, comorbidities, laboratory and immunological results, and radiological images of 182 hospitalized COVID‐19 children, were summarized and analyzed.

Results

The median age was 6 years, ranging from 3 days to 15 years, and there were more boys (male‐female ratio about 2:1) within the studied 182 patients. Most of the children were infected by family members. Fever (43.4%) and dry cough (44.5%) were common symptoms, and gastrointestinal manifestations accounted for 11.0%, including diarrhea, abdominal discomfort, and vomiting. 71.4% had abnormal chest computed tomography (CT) scan images, and typical signs of pneumonia were ground‐glass opacity and local patchy shadowing on admission. Laboratory results were mostly within normal ranges, and only a small ratio of lymphopenia (3.9%) and eosinopenia (29.5%) were observed. The majority (97.8%) of infected children were not severe, and 24 (13.2%) of them had asymptomatic infections. Compared to children without pneumonia (manifested as asymptomatic and acute upper respiratory infection), children with pneumonia were associated with higher percentages of the comorbidity history, symptoms of fever and cough, and increased levels of serum procalcitonin, alkaline phosphatase, and serum interleukins (IL)‐2, IL‐4, IL‐6, IL‐10, and TNF‐α. There were no differences in treatments, duration of hospitalization, time from first positive to first negative nucleic acid testing, and outcomes between children with mild pneumonia and without pneumonia. All the hospitalized COVID‐19 children had recovered except one death due to intussusception and sepsis. In 43 allergic children with COVID‐19, allergic rhinitis (83.7%) was the major disease, followed by drug allergy, atopic dermatitis, food allergy, and asthma. Demographics and clinical features were not significantly different between allergic and nonallergic groups. Allergic patients showed less increase in acute phase reactants, procalcitonin, D‐dimer, and aspartate aminotransferase levels compared with all patients. Immunological profiles including circulating T, B, and NK lymphocyte subsets, total immunoglobulin and complement levels, and serum cytokines did not show any difference in allergic and pneumonia groups. Neither eosinophil counts nor serum total immunoglobulin E (IgE) levels showed a significant correlation with other immunological measures, such as other immunoglobulins, complements, lymphocyte subset numbers, and serum cytokine levels.

Conclusion

Pediatric COVID‐19 patients tended to have a mild clinical course. Patients with pneumonia had higher proportion of fever and cough and increased inflammatory biomarkers than those without pneumonia. There was no difference between allergic and nonallergic COVID‐19 children in disease incidence, clinical features, and laboratory and immunological findings. Allergy was not a risk factor for developing and severity of SARS‐CoV‐2 infection and hardly influenced the disease course of COVID‐19 in children.

Asthma among hospitalized patients with COVID-19 and related outcomes

BACKGROUND

Several underlying conditions have been associated with severe acute respiratory syndrome coronavirus 2 illness, but it remains unclear whether underlying asthma is associated with worse coronavirus disease 2019 (COVID-19) outcomes.

OBJECTIVE

Given the high prevalence of asthma in the New York City area, our objective was to determine whether underlying asthma was associated with poor outcomes among hospitalized patients with severe COVID-19 compared with patients without asthma.

METHODS

Electronic heath records were reviewed for 1298 sequential patients 65 years or younger without chronic obstructive pulmonary disease who were admitted to our hospital system with a confirmed positive severe acute respiratory syndrome coronavirus 2 test result.

RESULTS

The overall prevalence of asthma among all hospitalized patients with COVID-19 was 12.6%, yet a higher prevalence (23.6%) was observed in the subset of 55 patients younger than 21 years. There was no significant difference in hospital length of stay, need for intubation, length of intubation, tracheostomy tube placement, hospital readmission, or mortality between patients with and without asthma. Observations between patients with and without asthma were similar when stratified by obesity, other comorbid conditions (ie, hypertension, hyperlipidemia, and diabetes), use of controller asthma medication, and absolute eosinophil count.

CONCLUSIONS

Among hospitalized patients 65 years or younger with severe COVID-19, asthma diagnosis was not associated with worse outcomes, regardless of age, obesity, or other high-risk comorbidities. Future population-based studies are needed to investigate the risk of developing COVID-19 among patients with asthma once universal testing becomes readily available.

Clinical characteristics of 140 patients infected with SARS-CoV-2 in Wuhan, China

BACKGROUND

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been widely spread. We aim to investigate the clinical characteristic and allergy status of patients infected with SARS-CoV-2.

METHODS

Electronic medical records including demographics, clinical manifestation, comorbidities, laboratory data, and radiological materials of 140 hospitalized COVID-19 patients, with confirmed result of SARS-CoV-2 viral infection, were extracted and analyzed.

RESULTS

An approximately 1:1 ratio of male (50.7%) and female COVID-19 patients was found, with an overall median age of 57.0 years. All patients were community-acquired cases. Fever (91.7%), cough (75.0%), fatigue (75.0%), and gastrointestinal symptoms (39.6%) were the most common clinical manifestations, whereas hypertension (30.0%) and diabetes mellitus (12.1%) were the most common comorbidities. Drug hypersensitivity (11.4%) and urticaria (1.4%) were self-reported by several patients. Asthma or other allergic diseases were not reported by any of the patients. Chronic obstructive pulmonary disease (COPD, 1.4%) patients and current smokers (1.4%) were rare. Bilateral ground-glass or patchy opacity (89.6%) was the most common sign of radiological finding. Lymphopenia (75.4%) and eosinopenia (52.9%) were observed in most patients. Blood eosinophil counts correlate positively with lymphocyte counts in severe (r = .486, P < .001) and nonsevere (r = .469, P < .001) patients after hospital admission. Significantly higher levels of D-dimer, C-reactive protein, and procalcitonin were associated with severe patients compared to nonsevere patients (all P < .001).

CONCLUSION

Detailed clinical investigation of 140 hospitalized COVID-19 cases suggests eosinopenia together with lymphopenia may be a potential indicator for diagnosis. Allergic diseases, asthma, and COPD are not risk factors for SARS-CoV-2 infection. Older age, high number of comorbidities, and more prominent laboratory abnormalities were associated with severe patients.

A cross-reactive mouse monoclonal antibody against rhinovirus mediates phagocytosis in vitro

Rhinoviruses (RVs) are the main cause of the common cold worldwide. To date, more than 160 types of the virus have been recognized, categorized into three major species - A, B, and C. There are currently no approved vaccines available to prevent infection with RVs. To elicit antibodies against conserved regions located on capsid proteins of RV A viruses, mice were sequentially vaccinated with DNA plasmids encoding capsid proteins of different RV A types. After a final boost with whole virus, antibody-expressing hybridomas were generated. After isotyping, 11 monoclonal antibodies (mAbs) expressing an IgG subtype Fc-domain were selected for further expansion and purification. Three mAbs showed cross-reactivity against multiple strains of RV A viruses by ELISA, including strains A1A, A1B, A15, A16 and A49. Other mAbs had strain-specific binding patterns, with the majority of mAbs showing reactivity to RV-A15, the strain used for the final vaccination. We found that the RV-A15-specific mAbs, but not the cross-reactive mAbs, had neutralizing activity against RV-A15. An antibody dependent cellular phagocytosis (ADCP) assay revealed substantial ADCP activity for one of the cross-reactive mAbs. Epitope mapping of the neutralizing mAbs via escape mutant virus generation revealed a shared binding epitope on VP1 of RV-A15 for several neutralizing mAbs. The epitope of the ADCP-active, non-neutralizing mAb was determined by microarray analysis of peptides generated from the VP1 capsid protein. VP1-specific, cross-reactive antibodies, especially those with ADCP activity, could contribute to protection against RV infections.

Aberrant cell migration contributes to defective airway epithelial repair in childhood wheeze

Abnormal wound repair has been observed in the airway epithelium of patients with chronic respiratory diseases, including asthma. Therapies focusing on repairing vulnerable airways, particularly in early life, present a potentially novel treatment strategy. We report defective lower airway epithelial cell repair to strongly associate with common pre-school-aged and school-aged wheezing phenotypes, characterized by aberrant migration patterns and reduced integrin α5β1 expression. Next generation sequencing identified the PI3K/Akt pathway as the top upstream transcriptional regulator of integrin α5β1, where Akt activation enhanced repair and integrin α5β1 expression in primary cultures from children with wheeze. Conversely, inhibition of PI3K/Akt signaling in primary cultures from children without wheeze reduced α5β1 expression and attenuated repair. Importantly, the FDA-approved drug celecoxib - and its non-COX2-inhibiting analogue, dimethyl-celecoxib - stimulated the PI3K/Akt-integrin α5β1 axis and restored airway epithelial repair in cells from children with wheeze. When compared with published clinical data sets, the identified transcriptomic signature was also associated with viral-induced wheeze exacerbations highlighting the clinical potential of such therapy. Collectively, these results identify airway epithelial restitution via targeting the PI3K-integrin α5β1 axis as a potentially novel therapeutic avenue for childhood wheeze and asthma. We propose that the next step in the therapeutic development process should be a proof-of-concept clinical trial, since relevant animal models to test the crucial underlying premise are unavailable.

CCR5 attenuates neutrophilic airway inflammation exacerbated by infection with rhinovirus

Human rhinovirus (hRV) is the most common cause of asthma exacerbation characterized by clinical and pathophysiological heterogeneity. Steroid-sensitive, Th2 type-eosinophilic asthma has been somewhat studied, but hRV-induced neutrophilic asthma exacerbation is poorly understood. Here, CCR5 was found to play a role in attenuating neutrophilic airway inflammation in hRV-induced asthma exacerbation using chicken ovalbumin (OVA)-based model. CCR5 deficiency resulted in exacerbated neutrophilic asthmatic responses in airways following hRV infection. CCR5-deficient mice showed enhanced mucus expression and altered expression of tight junction proteins in lung tissues. CCR5-deficient mice were also manifested with influx of CD45⁺CD11b⁺Siglec-F⁺Gr-1⁺ neutrophils, along with enhanced production of IL-17A, IFN-γ, IL-6, IL-1β cytokines in inflamed tissues. In contrast, CCR5-deficient mice elicited down-regulation of Th2-related cytokine proteins following hRV infection. More interestingly, the lack of CCR5 altered the equilibrium of CD4⁺FoxP3⁺ Tregs and IL-17⁺CD4⁺ Th17 in inflamed tissues. CCR5-deficient mice showed increased frequency and absolute number of IL-17-producing CD4⁺ Th17 cells in lung tissues compared to wild-type mice, whereas the reduced infiltration of CD4⁺FoxP3⁺ Treg cells was observed. CCR5 deficiency resulted in the skewed production of Th17 and Th1 cytokines in lymph nodes and lungs upon OVA stimulation. Likewise, CCR5-deficient mice showed enhanced expression of Th17-inducing cytokines (IL-1β, IL-6, and TNF-α) in lung tissues. These results imply that CCR5 deficiency facilitates Th17 airway inflammation during hRV-induced asthma exacerbation, along with suppressing Th2 responses. Furthermore, our results suggest that CCR5 attenuates hRV-induced neutrophilic airway inflammation through conserving the equilibrium of CD4⁺Foxp3⁺ Treg cells and IL-17⁺CD4⁺ Th17 cells in hRV-induced asthma exacerbation.

Convergence of Inflammatory Pathways in Allergic Asthma and Sickle Cell Disease

The underlying pathologies of sickle cell disease and asthma share many characteristics in terms of respiratory inflammation. The principal mechanisms of pulmonary inflammation are largely distinct, but activation of common pathways downstream of the initial inflammatory triggers may lead to exacerbation of both disease states. The altered inflammatory landscape of these respiratory pathologies can differentially impact respiratory pathogen susceptibility in patients with sickle cell disease and asthma. How these two distinct diseases behave in a comorbid setting can further exacerbate pulmonary complications associated with both disease states and impact susceptibility to respiratory infection. This review will provide a concise overview of how asthma distinctly affects individuals with sickle cell disease and how pulmonary physiology and inflammation are impacted during comorbidity.