Airway microbiota-host interactions regulate secretory leukocyte protease inhibitor levels and influence allergic airway inflammation

Homeostatic mucosal immune responses are fine-tuned by naturally evolved interactions with native microbes, and integrating these relationships into experimental models can provide new insights into human diseases. Here, we leverage a murine-adapted airway microbe, Bordetella pseudohinzii (Bph), to investigate how chronic colonization impacts mucosal immunity and the development of allergic airway inflammation (AAI). Colonization with Bph induces the differentiation of interleukin-17A (IL-17A)-secreting T-helper cells that aid in controlling bacterial abundance. Bph colonization protects from AAI and is associated with increased production of secretory leukocyte protease inhibitor (SLPI), an antimicrobial peptide with anti-inflammatory properties. These findings are additionally supported by clinical data showing that higher levels of upper respiratory SLPI correlate both with greater asthma control and the presence of Haemophilus, a bacterial genus associated with AAI. We propose that SLPI could be used as a biomarker of beneficial host-commensal relationships in the airway

The gut microbiota of people with asthma influences lung inflammation in gnotobiotic mice

The gut microbiota in early childhood is linked to asthma risk, but may continue to affect older patients with asthma. Here, we profile the gut microbiota of 38 children (19 asthma, median age 8) and 57 adults (17 asthma, median age 28) by 16S rRNA sequencing and find individuals with asthma harbored compositional differences from healthy controls in both adults and children. We develop a model to aid the design of mechanistic experiments in gnotobiotic mice and show enterotoxigeni

Global Initiative for Asthma (GINA) strategy 2021 - executive summary and rationale for key changes.

The Global Initiative for Asthma (GINA) Strategy Report provides clinicians with an annually updated evidence-based strategy for asthma management and prevention, which can be adapted for local circumstances (e.g., medication availability). This article summarizes key recommendations from GINA 2021, and the evidence underpinning recent changes. GINA recommends that asthma in adults and adolescents should not be treated solely with short-acting beta2-agonist (SABA), because of the risks of SABA-only treatment and SABA overuse, and evidence for benefit of inhaled corticosteroids (ICS). Large trials show that as-needed combination ICS-formoterol reduces severe exacerbations by ≥60% in mild asthma compared with SABA alone, with similar exacerbation, symptom, lung function and inflammatory outcomes as daily ICS plus as-needed SABA. Key changes in GINA 2021 include division of the treatment figure for adults/adolescents into two tracks. Track 1 (preferred) has low-dose ICS-formoterol as the reliever at all steps: as-needed only in Steps 1-2 (mild asthma), and with daily maintenance ICS formoterol (maintenance-and-reliever therapy, MART) in Steps 3-5. Track 2 (alternative) has as-needed SABA across all steps, plus regular ICS (Step 2) or ICS-long-acting beta2-agonist (LABA) (Steps 3-5). For adults with moderate-to-severe asthma, GINA makes additional recommendations in Step 5 for add-on long-acting muscarinic antagonists and azithromycin, with add-on biologic therapies for severe asthma. For children 6-11 years, new treatment options are added at Steps 3-4. Across all age-groups and levels of severity, regular personalized assessment, treatment of modifiable risk factors, self-management education, skills training, appropriate medication adjustment and review remain essential to optimize asthma outcomes

A distributed geospatial approach to describe community characteristics for multisite studies

Understanding place-based contributors to health requires geographically and culturally diverse study populations, but sharing location data is a significant challenge to multisite studies. Here, we describe a standardized and reproducible method to perform geospatial analyses for multisite studies. Using census tract-level information, we created software for geocoding and geospatial data linkage that was distributed to a consortium of birth cohorts located throughout the USA. Individual sites performed geospatial linkages and returned tract-level information for 8810 children to a central site for analyses. Our generalizable approach demonstrates the feasibility of geospatial analyses across study sites to promote collaborative translational research

GINA 2019: a fundamental change in asthma management

In April 2019, the Global Initiative for Asthma (GINA) (box 1) published new recommendations that might be considered the most fundamental change in asthma management in 30 years. The new recommendations follow a decade-long programme of work by GINA, prompted by concerns about the risks and consequences of the long-standing approach of commencing asthma treatment with short-acting β2-agonists (SABA) alone. These initiatives were aimed at obtaining evidence about effective treatment options for mild asthma and providing consistent messaging for patients and clinicians across the spectrum of asthma severity

African-specific alleles modify risk for asthma at the 17q12-q21 locus in African Americans

BACKGROUND: Asthma is the most common chronic disease in children, occurring at higher frequencies and with more severe disease in children with African ancestry. METHODS: We tested for association with haplotypes at the most replicated and significant childhood-onset asthma locus at 17q12-q21 and asthma in European American and African American children. Following this, we used whole-genome sequencing data from 1060 African American and 100 European American individuals to identify novel variants on a high-risk African American-specific haplotype. We characterized these variants in silico using gene expression and ATAC-seq data from airway epithelial cells, functional annotations from ENCODE, and promoter capture (pc)Hi-C maps in airway epithelial cells. Candidate causal variants were then assessed for correlation with asthma-associated phenotypes in African American children and adults. RESULTS: Our studies revealed nine novel African-specific common variants, enriched on a high-risk asthma haplotype, which regulated the expression of GSDMA in airway epithelial cells and were associated with features of severe asthma. Using ENCODE annotations, ATAC-seq, and pcHi-C, we narrowed the associations to two candidate causal variants that are associated with features of T2 low severe asthma. CONCLUSIONS: Previously unknown genetic variation at the 17q12-21 childhood-onset asthma locus contributes to asthma severity in individuals with African ancestries. We suggest that many other population-specific variants that have not been discovered in GWAS contribute to the genetic risk for asthma and other common diseases

Adrenal suppression: A practical guide to the screening and management of this under-recognized complication of inhaled corticosteroid therapy

Inhaled corticosteroids (ICSs) are the most effective anti-inflammatory agents available for the treatment of asthma and represent the mainstay of therapy for most patients with the disease. Although these medications are considered safe at low-to-moderate doses, safety concerns with prolonged use of high ICS doses remain; among these concerns is the risk of adrenal suppression (AS). AS is a condition characterized by the inability to produce adequate amounts of the glucocorticoid, cortisol, which is critical during periods of physiological stress. It is a proven, yet under-recognized, complication of most forms of glucocorticoid therapy that can persist for up to 1 year after cessation of corticosteroid treatment. If left unnoticed, AS can lead to significant morbidity and even mortality. More than 60 recent cases of AS have been described in the literature and almost all cases have involved children being treated with ≥500 μg/day of fluticasone

The human immune response to respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is an important etiological agent of respiratory infections, particularly in children. Much information regarding the immune response to RSV comes from animal models and in vitro studies. Here, we provide a comprehensive description of the human immune response to RSV infection, based on a systematic literature review of research on infected humans. There is an initial strong neutrophil response to RSV infection in humans, which is positively correlated with disease severity and mediated by interleukin-8 (IL-8). Dendritic cells migrate to the lungs as the primary antigen-presenting cell. An initial systemic T-cell lymphopenia is followed by a pulmonary CD8(+) T-cell response, mediating viral clearance. Humoral immunity to reinfection is incomplete, but RSV IgG and IgA are protective. B-cell-stimulating factors derived from airway epithelium play a major role in protective antibody generation. Gamma interferon (IFN-γ) has a strongly protective role, and a Th2-biased response may be deleterious. Other cytokines (particularly IL-17A), chemokines (particularly CCL-5 and CCL-3), and local innate immune factors (including cathelicidins and IFN-λ) contribute to pathogenesis. In summary, neutrophilic inflammation is incriminated as a harmful response, whereas CD8(+) T cells and IFN-γ have protective roles. These may represent important therapeutic targets to modulate the immunopathogenesis of RSV infection

Association of the Gene Polymorphisms IFN-γ +874, IL-13 −1055 and IL-4 −590 with Patterns of Reinfection with Schistosoma mansoni

Approximately 200 million people have schistosomiasis in parts of Africa, South America, the Middle East, the Caribbean and Asia. Several studies of multiple treatments and reinfections indicate that some people develop resistance to reinfection. Of all the immunologic findings associated with such studies, the most consistent observation is that resistance (usually defined as lower levels of infection upon reinfection) correlates with high IgE and low IgG4 antibodies against schistosome antigens. Our studies test whether single nucleotide polymorphisms residing in the gene or promoter regions of cytokines pivotal in controlling production of these antibody isotypes are different amongst those that develop resistance to reinfection as opposed to those that do not. Through genotyping of these polymorphisms in a cohort of occupationally exposed car washers, we found that men with certain genotypic patterns of polymorphisms in IL-4, IFN-γ, and IL-13 were significantly more likely to be resistant to reinfection than those with different patterns. These data provide initial insights into the potential genetic foundation of propensities of people to develop resistance to reinfection by schistosomes, and offer a basis for further molecular studies of how these polymorphisms might work at the transcriptional and gene product level in cells stimulated by schistosome antigens