Aspergillus fumigatus binding IgA and IgG1 are increased in bronchoalveolar lavage fluid of horses with neutrophilic asthma.

Introduction: Equine asthma (EA) is a common lower airway disease in horses, but whether its pathogenesis is allergic is ambiguous. Extrinsic stimuli like hay dust induce acute exacerbation of clinical signs and sustained local neutrophilic inflammation in susceptible horses. Aspergillus fumigatus is an EA stimulus, but it is unclear if it merely acts as an IgE-provoking allergen. We aimed to comprehensively analyze immunoglobulin (Ig) isotypes in EA, elucidating their binding to different A. fumigatus antigens, and their quantities systemically in serum and locally in bronchoalveolar lavage fluid (BALF). Methods: Serum and BALF from healthy horses (HE, n = 18) and horses with mild-moderate asthma (MEA, n = 20) or severe asthma (SEA, n = 24) were compared. Ig isotype (IgG1, IgG3/5, IgG4/7, IgG6, IgA, and IgE) binding to nine antigens (A. fumigatus lysate, and recombinant Asp f 1, Asp f 7, Asp f 8, dipeptidyl-peptidase 5, class II aldolase/adducin domain protein, glucoamylase, beta-hexosaminidase, and peptide hydrolase) was compared by enzyme-linked immunosorbent assays. Total Ig isotype contents were determined by bead-based assays. Results: MEA and SEA differed from HE but hardly from each other. Compared to HE, asthmatic horses showed increased anti-A. fumigatus binding of IgG (BALF and serum) and IgA (BALF). Serum and BALF IgE binding and total IgE contents were similar between HE and EA. Single antigens, as well as A. fumigatus lysate, yielded similar Ig binding patterns. Serum and BALF IgG1 binding to all antigens was increased in SEA and to several antigens in MEA. Serum IgG4/7 binding to two antigens was increased in SEA. BALF IgA binding to all antigens was increased in SEA and MEA. Total BALF IgG1 and IgG4/7 contents were increased in SEA, and serum IgG4/7 content was increased in MEA compared to HE. Yet, total isotype contents differentiated EA and HE less clearly than antigen-binding Ig. Discussion: A. fumigatus immunogenicity was confirmed without identification of single dominant antigens here. A. fumigatus provoked elevated BALF IgG1 and IgA binding, and these isotypes appear relevant for neutrophilic EA, which does not support allergy. BALF Ig isotype differentiation beyond IgE is crucial for a comprehensive analysis of immune responses to fungi in EA pathogenesis.

Environmental and structural factors associated with bacterial diversity in household dust across the Arizona-Sonora border.

We previously reported that asthma prevalence was higher in the United States (US) compared to Mexico (MX) (25.8% vs. 8.4%). This investigation assessed differences in microbial dust composition in relation to demographic and housing characteristics on both sides of the US-MX Border. Forty homes were recruited in the US and MX. Home visits collected floor dust and documented occupants' demographics, asthma prevalence, housing structure, and use characteristics. US households were more likely to have inhabitants who reported asthma when compared with MX households (30% vs. 5%) and had significantly different flooring types. The percentage of households on paved roads, with flushing toilets, with piped water and with air conditioning was higher in the US, while dust load was higher in MX. Significant differences exist between countries in the microbial composition of the floor dust. Dust from Mexican homes was enriched with Alishewanella, Paracoccus, Rheinheimera genera and Intrasporangiaceae family. A predictive metagenomics analysis identified 68 significantly differentially abundant functional pathways between US and MX. This study documented multiple structural, environmental, and demographic differences between homes in the US and MX that may contribute to significantly different microbial composition of dust observed in these two countries.

[Exploratory analysis of gut microbiota differences in patients with bronchial asthma of different inflammatory types].

Objective: To observe the characteristics and differences of gut microbiota in asthma patients with different inflammatory types through metagenomic analysis. Methods: Adults aged ≥18 years who visited the Respiratory Clinic of Peking University Third Hospital from August 1, 2021 to August 31, 2022 and were primarily diagnosed with asthma were selected as the study subjects. Finally, 29 patients with stable asthma were included. Fresh fecal samples were collected and the fecal DNA was extracted for high-throughput 16sRNA sequencing of gut microbiota. The diversity and community structure of gut microbiota in different groups of asthma patients were compared, and the species differences were analyzed through random forest and LEfSe analysis. Results: There were sex-based differences in asthma patients with different types of inflammation, and the proportion of female patients was higher in neutrophilic asthma patients (χ2=4.14, P=0.042). There was no significant intergroup difference in the alpha diversity of gut microbiota among asthma patients with different inflammatory types, but there were significant differences in the microbiome. Patients with neutrophilic asthma had higher relative abundance of Bacillales (P=0.029) and Oscillospiraceae (P=0.015). In species LEfSe analysis, patients with eosinophilic asthma had a higher relative abundance of fungi. Conclusion: There are intergroup differences in the gut microbiota of asthma patients with different inflammation types, and fungi are biomarkers that distinguish the differences in gut microbiota between patients with eosinophilic asthma and neutrophilic asthma.

Microbial variations in sputum cultures among hospitalized patients with community-acquired pneumonia: differences in sputum microbiota between asthma and COPD patients.

OBJECTIVE: To assess differences in the sputum microbiota of community-acquired pneumonia (CAP) patients with either COPD or asthma, specifically focusing on a patient population in Turkey. METHODS: This retrospective study included hospitalized patients > 18 years of age with a diagnosis of pneumonia between January of 2021 and January of 2023. Participants were recruited from two hospitals, and three patient groups were considered: CAP patients with asthma, CAP patients with COPD, and CAP patients without COPD or asthma. RESULTS: A total of 246 patients with CAP were included in the study, 184 (74.8%) and 62 (25.2%) being males and females, with a mean age of 66 ± 14 years. Among the participants, 52.9% had COPD, 14.2% had asthma, and 32.9% had CAP but no COPD or asthma. Upon analysis of sputum cultures, positive sputum culture growth was observed in 52.9% of patients. The most commonly isolated microorganisms were Pseudomonas aeruginosa (n = 40), Acinetobacter baumannii (n = 20), Klebsiella pneumoniae (n = 16), and Moraxella catarrhalis (n = 8). CAP patients with COPD were more likely to have a positive sputum culture (p = 0.038), a history of antibiotic use within the past three months (p = 0.03), utilization of long-term home oxygen therapy (p < 0.001), and use of noninvasive ventilation (p = 0.001) when compared with the other patient groups. Additionally, CAP patients with COPD had a higher CURB-65 score when compared with CAP patients with asthma (p = 0.004). CONCLUSIONS: This study demonstrates that CAP patients with COPD tend to have more severe presentations, while CAP patients with asthma show varied microbial profiles, underscoring the need for patient-specific management strategies in CAP.

Age-related effects of Mycoplasma pneumoniae infection and subsequent asthma exacerbation in children.

BACKGROUND: Mycoplasma pneumoniae causes community-acquired pneumonia in children and increases asthma risk, but large studies are lacking. OBJECTIVE: To assess the link between M. pneumoniae infection and to asthma exacerbation, in children with allergies, and age of infection impact. METHODS: This retrospective cohort study analyzed medical records of South Korean children between January 2002 and December 2017. The study's exposure was hospitalization with an M. pneumoniae-related diagnosis, and the outcome was defined as asthma exacerbation, confirmed by hospitalization at least 6 months after M. pneumoniae infection, with alternative validation using asthma diagnosis and systemic steroid prescription records. Hazard ratios (HRs) for asthma exacerbation risk were estimated for the matched cohort using a Cox proportional hazards model stratified by allergic comorbidities. Time-dependent covariates and age-stratified exposure groups were used to calculate odds ratios. RESULTS: The study included 84,074 children with M. pneumoniae infection and 336,296 unexposed children. Follow-up for 12.2 ± 2.3 years found the exposed group had a significant risk of asthma exacerbation (HR 2.86, 95% confidence interval [CI] 2.67-3.06) regardless of allergic comorbidities. The risk was highest (over threefold) in children infected between 24 and 71 months. Sensitivity analysis using an alternative definition of the outcome showed an HR of 1.38 (95% CI 1.35-1.42), further supporting the association between M. pneumoniae infection and asthma exacerbation. CONCLUSION: M. pneumoniae infection was significantly associated with an increased risk of subsequent asthma exacerbation regardless of allergic comorbidities. Further research needed for understanding and confirmation.

Gonadal sex and chromosome complement influence the gut microbiome in a mouse model of allergic airway inflammation.

Evidence abounds that gut microbiome components are associated with sex disparities in the immune system. However, it remains unclear whether the observed sex disparity in asthma incidence is associated with sex-dependent differences in immune-modulating gut microbiota, and/or its influence on allergic airway inflammatory processes. Using a mouse model of house dust mite (HDM)-induced allergic inflammation and the four core genotypes (FCGs) model, we have previously reported sex differences in lung inflammatory phenotypes. Here, we investigated associations of gut microbiomes with these phenotypes by challenging FCG mice [mouse with female sex chromosome and male gonad (XXM), mouse with female sex chromosome and female gonad (XXF), mouse with male sex chromosome and male gonad (XYM), and mouse with male sex chromosome and female gonad (XYF); n = 7/group] with HDM (25 µg) or PBS intranasally for 5 wk and collecting fecal samples. We extracted fecal DNA and analyzed the 16S microbiome via Targeted Metagenomic Sequencing. We compared α and ß diversity across genotypes and assessed the Firmicutes/Bacteroidetes (F/B) ratio. When comparing baseline and after exposure for the FCG, we found that the gut F/B ratio was only increased in the XXM genotype. We also found that α diversity was significantly increased in all FCG mice upon HDM challenge, with the highest increase in the XXF, and the lowest in the XXM genotypes. Similarly, ß diversity of the microbial community was also affected by challenge in a gonad- and chromosome-dependent manner. In summary, our results indicated that HDM treatment, gonads, and sex chromosomes significantly influence the gut microbial community composition. We concluded that allergic lung inflammation may be affected by the gut microbiome in a sex-dependent manner involving both hormonal and genetic influences.NEW & NOTEWORTHY Recently, the gut microbiome and its role in chronic respiratory disease have been the subject of extensive research and the establishment of its involvement in immune functions. Using the FCG mouse model, our findings revealed the influence of gonads and sex chromosomes on the microbial community structure before and after exposure to HDM. Our data provide a potential new avenue to better understand mediators of sex disparities associated with allergic airway inflammation.

Nasopharyngeal microbiota in children is associated with severe asthma exacerbations.

BACKGROUND: The respiratory microbiome has been associated with the etiology and disease course of asthma. OBJECTIVE: We sought to assess the nasopharyngeal microbiota in children with a severe asthma exacerbation and their associations with medication, air quality, and viral infection. METHODS: A cross-sectional study was performed among children aged 2 to 18 years admitted to the medium care unit (MCU; n = 84) or intensive care unit (ICU; n = 78) with an asthma exacerbation. For case-control analyses, we matched all cases aged 2 to 6 years (n = 87) to controls in a 1:2 ratio. Controls were participants of either a prospective case-control study or a longitudinal birth cohort (n = 182). The nasopharyngeal microbiota was characterized by 16S-rRNA-gene sequencing. RESULTS: Cases showed higher Shannon diversity index (ICU and MCU combined; P = .002) and a distinct microbial community composition when compared with controls (permutational multivariate ANOVA R2 = 1.9%; P < .001). We observed significantly higher abundance of Staphylococcus and "oral" taxa, including Neisseria, Veillonella, and Streptococcus spp. and a lower abundance of Dolosigranulum pigrum, Corynebacterium, and Moraxella spp. (MaAsLin2; q < 0.25) in cases versus controls. Furthermore, Neisseria abundance was associated with more severe disease (ICU vs MCU MaAslin2, P = .03; q = 0.30). Neisseria spp. abundance was also related with fine particulate matter exposure, whereas Haemophilus and Streptococcus abundances were related with recent inhaled corticosteroid use. We observed no correlations with viral infection. CONCLUSIONS: Our results demonstrate that children admitted with asthma exacerbations harbor a microbiome characterized by overgrowth of Staphylococcus and "oral" microbes and an underrepresentation of beneficial niche-appropriate commensals. Several of these associations may be explained by (environmental or medical) exposures, although cause-consequence relationships remain unclear and require further investigations.

Saccharomyces boulardii alleviates allergic asthma by restoring gut microbiota and metabolic homeostasis via up-regulation of METTL3 in an m6A-dependent manner.

BACKGROUND: Allergic asthma is a heterogeneous disease and new strategies are needed to prevent or treat this disease. Studies have shown that probiotic interventions are effective in preventing asthma. Here, we investigated the impact of Saccharomyces boulardii (S. boulardii) on ovalbumin (OVA)-induced allergic asthma in mice, as well as the underlying mechanisms. METHODS: First, we constructed a mouse asthma model using OVA and given S. boulardii intervention. Next, we measured N6-methyladenosine (m6A) levels in lung injury tissues. 16 s rRNA was employed to identify different gut microbiota in fecal samples. The analysis of differential metabolites in feces was performed by non-targeted metabolomics. Pearson correlation coefficient was utilized to analyze correlation between gut microbiota, metabolites and methyltransferase-like 3 (METTL3). Finally, we collected mouse feces treated by OVA and S. boulardii intervention for fecal microbiota transplantation (FMT) and interfered with METTL3. RESULTS: S. boulardii improved inflammation and oxidative stress and alleviated lung damage in asthmatic mice. In addition, S. boulardii regulated m6A modification levels in asthmatic mice. 16 s rRNA sequencing showed that S. boulardii remodeled gut microbiota homeostasis in asthmatic mice. Non-targeted metabolomics analysis showed S. boulardii restored metabolic homeostasis in asthmatic mice. There was a correlation between gut microbiota, differential metabolites, and METTL3 analyzed by Pearson correlation. Additionally, through FMT and interference of METTL3, we found that gut microbiota mediated the up-regulation of METTL3 by S. boulardii improved inflammation and oxidative stress in asthmatic mice, and alleviated lung injury. CONCLUSIONS: S. boulardii alleviated allergic asthma by restoring gut microbiota and metabolic homeostasis via up-regulation of METTL3 in an m6A-dependent manner.

Early-life nasal microbiota dynamics relate to longitudinal respiratory phenotypes in urban children.

BACKGROUND: Five distinct respiratory phenotypes based on latent classes of longitudinal patterns of wheezing, allergic sensitization. and pulmonary function measured in urban children from ages from 0 to 7 years have previously been described. OBJECTIVE: Our aim was to determine whether distinct respiratory phenotypes are associated with early-life upper respiratory microbiota development and environmental microbial exposures. METHODS: Microbiota profiling was performed using 16S ribosomal RNA-based sequencing of nasal samples collected at age 12 months (n = 120) or age 36 months (n = 142) and paired house dust samples collected at 3 months (12-month, n = 73; 36-month, n = 90) from all 4 centers in the Urban Environment and Childhood Asthma (URECA) cohort. RESULTS: In these high-risk urban children, nasal microbiota increased in diversity between ages 12 and 36 months (ß = 2.04; P = .006). Age-related changes in microbiota evenness differed significantly by respiratory phenotypes (interaction P = .0007), increasing most in the transient wheeze group. At age 12 months, respiratory illness (R2 = 0.055; P = .0001) and dominant bacterial genus (R2 = 0.59; P = .0001) explained variance in nasal microbiota composition, and enrichment of Moraxella and Haemophilus members was associated with both transient and high-wheeze respiratory phenotypes. By age 36 months, nasal microbiota was significantly associated with respiratory phenotypes (R2 = 0.019; P = .0376), and Moraxella-dominated microbiota was associated specifically with atopy-associated phenotypes. Analysis of paired house dust and nasal samples indicated that 12 month olds with low wheeze and atopy incidence exhibited the largest number of shared bacterial taxa with their environment. CONCLUSION: Nasal microbiota development over the course of early childhood and composition at age 3 years are associated with longitudinal respiratory phenotypes. These data provide evidence supporting an early-life window of airway microbiota development that is influenced by environmental microbial exposures in infancy and associates with wheeze- and atopy-associated respiratory phenotypes through age 7 years.

The airway microbiota of neonates colonized with asthma-associated pathogenic bacteria.

Culture techniques have associated colonization with pathogenic bacteria in the airways of neonates with later risk of childhood asthma, whereas more recent studies utilizing sequencing techniques have shown the same phenomenon with specific anaerobic taxa. Here, we analyze nasopharyngeal swabs from 1 month neonates in the COPSAC2000 prospective birth cohort by 16S rRNA gene sequencing of the V3-V4 region in relation to asthma risk throughout childhood. Results are compared with previous culture results from hypopharyngeal aspirates from the same cohort and with hypopharyngeal sequencing data from the later COPSAC2010 cohort. Nasopharyngeal relative abundance values of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are associated with the same species in the hypopharyngeal cultures. A combined pathogen score of these bacteria's abundance values is associated with persistent wheeze/asthma by age 7. No other taxa are associated. Compared to the hypopharyngeal aspirates from the COPSAC2010 cohort, the anaerobes Veillonella and Prevotella, which have previously been implicated in asthma development, are less commonly detected in the COPSAC2000 nasopharyngeal samples, but correlate with the pathogen score, hinting at latent community structures that bridge current and previous results. These findings have implications for future asthma prevention efforts.

Allergic fungal rhinosinusitis: What we can learn from allergic bronchopulmonary mycosis.

Allergic fungal rhinosinusitis (AFRS) and allergic bronchopulmonary mycosis (ABPM) are inflammatory disorders of the respiratory tract resulting from type 1 and 3 hypersensitivity reactions against fungi. The hallmark features of both diseases are eosinophil infiltration into the airway mucosa caused by localized type 2 inflammation and concomitant viscid secretions in the airways. Eosinophilic mucin-induced compression of adjacent anatomic structures leads to bone erosion and central bronchiectasis in the upper and lower respiratory tracts, respectively. Although these diseases share common features in their pathogenesis, they also exhibit notable differences. Epidemiologic findings are diverse, with AFRS typically presenting at a younger age, exhibiting less complicated bronchial asthma, and displaying lower total immunoglobulin E levels in laboratory findings compared with ABPM. Furthermore, despite their similar pathogenesis, the rarity of sinio-bronchial allergic mycosis in both AFRS and ABPM underscores the distinctions between these two diseases. This review aims to clarify the similarities and differences in the pathogenesis of AFRS and ABPM to determine what can be learned about AFRS from ABPM, where more is known.

Haemophilus influenzae and Moraxella catarrhalis in sputum of severe asthma with inflammasome and neutrophil activation.

BACKGROUND: Because of altered airway microbiome in asthma, we analysed the bacterial species in sputum of patients with severe asthma. METHODS: Whole genome sequencing was performed on induced sputum from non-smoking (SAn) and current or ex-smoker (SAs/ex) severe asthma patients, mild/moderate asthma (MMA) and healthy controls (HC). Data were analysed by asthma severity, inflammatory status and transcriptome-associated clusters (TACs). RESULTS: α-diversity at the species level was lower in SAn and SAs/ex, with an increase in Haemophilus influenzae and Moraxella catarrhalis, and Haemophilus influenzae and Tropheryma whipplei, respectively, compared to HC. In neutrophilic asthma, there was greater abundance of Haemophilus influenzae and Moraxella catarrhalis and in eosinophilic asthma, Tropheryma whipplei was increased. There was a reduction in α-diversity in TAC1 and TAC2 that expressed high levels of Haemophilus influenzae and Tropheryma whipplei, and Haemophilus influenzae and Moraxella catarrhalis, respectively, compared to HC. Sputum neutrophils correlated positively with Moraxella catarrhalis and negatively with Prevotella, Neisseria and Veillonella species and Haemophilus parainfluenzae. Sputum eosinophils correlated positively with Tropheryma whipplei which correlated with pack-years of smoking. α- and ß-diversities were stable at one year. CONCLUSIONS: Haemophilus influenzae and Moraxella catarrhalis were more abundant in severe neutrophilic asthma and TAC2 linked to inflammasome and neutrophil activation, while Haemophilus influenzae and Tropheryma whipplei were highest in SAs/ex and in TAC1 associated with highest expression of IL-13 type 2 and ILC2 signatures with the abundance of Tropheryma whipplei correlating positively with sputum eosinophils. Whether these bacterial species drive the inflammatory response in asthma needs evaluation.

The Fungal Microbiome of the Upper Airway Is Associated With Future Loss of Asthma Control and Exacerbation Among Children With Asthma.

BACKGROUND: Accumulating evidence suggests that the upper airway bacterial microbiota is implicated in asthma inception, severity, and exacerbation. Unlike bacterial microbiota, the role of the upper airway fungal microbiome (mycobiome) in asthma control is poorly understood. RESEARCH QUESTION: What are the upper airway fungal colonization patterns among children with asthma and their relationship with subsequent loss of asthma control and exacerbation of asthma? STUDY DESIGN AND METHODS: The study was coupled with the Step Up Yellow Zone Inhaled Corticosteroids to Prevent Exacerbations (ClinicalTrials.gov Identifier: NCT02066129) clinical trial. The upper airway mycobiome was investigated using Internal transcribed spacer 1 (ITS1) sequencing of nasal blow samples collected from children with asthma when asthma was well controlled (baseline, n = 194) and during early signs of loss of asthma control (yellow zone [YZ], n = 107). RESULTS: At baseline, 499 fungal genera were detected in the upper airway samples, with two commensal fungal species, Malassezia globosa and Malassezia restricta, being most dominant. The relative abundance of Malassezia species varies by age, BMI, and race. Higher relative abundance of M globosa at baseline was associated with lower risk of future YZ episodes (P = .038) and longer time to development of first YZ episode (P = .022). Higher relative abundance of M globosa at YZ episode was associated with lower risk of progression from YZ episode to severe asthma exacerbation (P = .04). The upper airway mycobiome underwent significant changes from baseline to YZ episode, and increased fungal diversity was correlated highly with increased bacterial diversity (ρ = 0.41). INTERPRETATION: The upper airway commensal mycobiome is associated with future asthma control. This work highlights the importance of the mycobiota in asthma control and may contribute to the development of fungi-based markers to predict asthma exacerbation.

Upper respiratory tract microbiota is associated with small airway function and asthma severity.

BACKGROUND: Characteristics of airway microbiota might influence asthma status or asthma phenotype. Identifying the airway microbiome can help to investigate its role in the development of asthma phenotypes or small airway function. METHODS: Bacterial microbiota profiles were analyzed in induced sputum from 31 asthma patients and 12 healthy individuals from Beijing, China. Associations between small airway function and airway microbiomes were examined. RESULTS: Composition of sputum microbiota significantly changed with small airway function in asthma patients. Two microbiome-driven clusters were identified and characterized by small airway function and taxa that had linear relationship with small airway functions were identified. CONCLUSIONS: Our findings confirm that airway microbiota was associated with small airway function in asthma patients.

Microbial dysbiosis and childhood asthma development: Integrated role of the airway and gut microbiome, environmental exposures, and host metabolic and immune response.

Asthma is a chronic and heterogeneous respiratory disease with many risk factors that typically originate during early childhood. A complex interplay between environmental factors and genetic predisposition is considered to shape the lung and gut microbiome in early life. The growing literature has identified that changes in the relative abundance of microbes (microbial dysbiosis) and reduced microbial diversity, as triggers of the airway-gut axis crosstalk dysregulation, are associated with asthma development. There are several mechanisms underlying microbial dysbiosis to childhood asthma development pathways. For example, a bacterial infection in the airway of infants can lead to the activation and/or dysregulation of inflammatory pathways that contribute to bronchoconstriction and bronchial hyperresponsiveness. In addition, gut microbial dysbiosis in infancy can affect immune development and differentiation, resulting in a suboptimal balance between innate and adaptive immunity. This evolving dysregulation of secretion of pro-inflammatory mediators has been associated with persistent airway inflammation and subsequent asthma development. In this review, we examine current evidence around associations between the airway and gut microbial dysbiosis with childhood asthma development. More specifically, this review focuses on discussing the integrated roles of environmental exposures, host metabolic and immune responses, airway and gut microbial dysbiosis in driving childhood asthma development.

Dermatophagoides pteronyssinus allergen Der p 22: Cloning, expression, IgE-binding in asthmatic children, and immunogenicity.

BACKGROUND: Dust mite extract contains multiple components that, while useful in clinical allergy diagnosis and treatment, can cause serious side effects. Defining components of dust mite extract is important their contributions to allergic disease. This study aimed to characterize a novel dust mite allergen, Der p 22. METHODS: We amplified the cDNA encoding Der p 22 from total RNA of the mite Dermatophagoides pteronyssinus, and inserted it into an expression construct for transformation to competent cells. Purified recombinant (r) Der p 22 was tested for IgE-binding reactivity in sera obtained from children with allergic asthma by the Affiliated Wuxi Children's Hospital of Nanjing Medical University (Jiangsu, China). rDer p 22 also was used to challenge BALB/c mice to assess effects on T helper cells and cytokine levels and applied to cultured lung epithelial cells to evaluate apoptosis and cytokine secretion. RESULTS: rDer p 22 bound to IgE in 93.75% of sera from pediatric allergic asthma patients. Mice challenged with rDer p 22 had altered Th1/Th2 ratios in spleen and lymph, and lower levels of cytokines IFN-γ but higher levels of IL-4 and IL-10 in alveolar lavage fluid compared with controls (p < .05). Cultured lung epithelial cells had greater apoptosis rates and exhibited higher levels of IL-6, IL-8, and GM-CSF when treated with rDer p 22 compared with control treatment (p < .05). CONCLUSIONS: Recombinant Der p 22 exhibited high IgE-binding rates in allergic children, indicating the activity of the recombinant protein and suggesting this novel allergen may be appropriate for inclusion in an allergy diagnostic workup. This finding is supported by in vitro and mouse in vivo studies showing rDer p 22 induced strong allergenic reactivity and apoptosis.

Relationship between inflammatory status and microbial composition in severe asthma and during exacerbation.

BACKGROUND: In T2-mediated severe asthma, biologic therapies, such as mepolizumab, are increasingly used to control disease. Current biomarkers can indicate adequate suppression of T2 inflammation, but it is unclear whether they provide information about airway microbial composition. We investigated the relationships between current T2 biomarkers and microbial profiles, characteristics associated with a ProteobacteriaHIGH microbial profile and the effects of mepolizumab on airway ecology. METHODS: Microbiota sequencing was performed on sputum samples obtained at stable and exacerbation state from 140 subjects with severe asthma participating in two clinical trials. Inflammatory subgroups were compared on the basis of biomarkers, including FeNO and sputum and blood eosinophils. ProteobacteriaHIGH subjects were identified by Proteobacteria to Firmicutes ratio ≥0.485. Where paired sputum from stable visits was available, we compared microbial composition at baseline and following ≥12 weeks of mepolizumab. RESULTS: Microbial composition was not related to inflammatory subgroup based on sputum or blood eosinophils. FeNO ≥50 ppb when stable and at exacerbation indicated a group with less dispersed microbial profiles characterised by high alpha-diversity and low Proteobacteria. ProteobacteriaHIGH subjects were neutrophilic and had a longer time from asthma diagnosis than ProteobacteriaLOW subjects. In those studied, mepolizumab did not alter airway bacterial load or lead to increased Proteobacteria. CONCLUSION: High FeNO could indicate a subgroup of severe asthma less likely to benefit from antimicrobial strategies at exacerbation or in the context of poor control. Where FeNO is <50 ppb, biomarkers of microbial composition are required to identify those likely to respond to microbiome-directed strategies. We found no evidence that mepolizumab alters airway microbial composition.

Asthma and Wheeze Severity and the Oropharyngeal Microbiota in Children and Adolescents.

Rationale: There is a major unmet need for improving the care of children and adolescents with severe asthma and wheeze. Identifying factors contributing to disease severity may lead to improved diagnostics, biomarkers, or therapies. The airway microbiota may be such a key factor. Objectives: To compare the oropharyngeal airway microbiota of children and adolescents with severe and mild/moderate asthma/wheeze. Methods: Oropharyngeal swab samples from school-age and preschool children in the European U-BIOPRED (Unbiased BIOmarkers in the PREDiction of respiratory disease outcomes) multicenter study of severe asthma, all receiving severity-appropriate treatment, were examined using 16S ribosomal RNA gene sequencing. Bacterial taxa were defined as amplicon sequence variants. Results: We analyzed 241 samples from four cohorts: A) 86 school-age children with severe asthma; B) 39 school-age children with mild/moderate asthma; C) 65 preschool children with severe wheeze; and D) 51 preschool children with mild/moderate wheeze. The most common bacteria were Streptococcus (mean relative abundance, 33.5%), Veillonella (10.3%), Haemophilus (7.0%), Prevotella (5.9%), and Rothia (5.5%). Age group (school-age vs. preschool) was associated with the microbiota in ß-diversity analysis (F = 3.32, P = 0.011) and in a differential abundance analysis (28 significant amplicon sequence variants). Among all children, we found no significant difference in the microbiota between children with severe and mild/moderate asthma/wheeze in univariable ß-diversity analysis (F = 1.99, P = 0.08, N = 241), but a significant difference in a multivariable model (F = 2.66, P = 0.035), including the number of exacerbations in the previous year. Age was also significant when expressed as a microbial maturity score (Spearman Rho, 0.39; P = 4.6 × 10-10); however, this score was not associated with asthma/wheeze severity. Conclusions: There was a modest difference in the oropharyngeal airway microbiota between children with severe and mild/moderate asthma/wheeze across all children but not in individual age groups, and a strong association between the microbiota and age. This suggests the oropharyngeal airway microbiota as an interesting entity in studying asthma severity, but probably without the strength to serve as a biomarker for targeted intervention.