The STOPPA Twin Study Explains the Exhaled Nitric Oxide and Asthma Link by Genetics and Sensitization

Development of sensitization to peanut and storage proteins and relation to markers of airway and systemic inflammation: A 24-year follow-up

BACKGROUND

Long-time data of peanut allergy over time is sparse. We aimed to study the longitudinal development of sensitization to peanut extract and storage protein allergen molecules and associations with asthma status, airway and systemic inflammation markers.

METHODS

The Swedish birth cohort BAMSE followed 4089 participants with questionnaires, clinical investigations and blood sampling between 0 and 24 years. Information on (i) background factors at 2 months, (ii) peanut allergy symptoms and IgE data (ImmunoCAP) at 4, 8, 16, and 24 years, and (iii) IgE to storage proteins, lung function data including exhaled nitric oxide (FENO) as well as systemic inflammatory markers at 24 years of age were collected.

RESULTS

The prevalence of peanut extract sensitization, defined as IgE ≥ 0.35 kU_A /L, was 5.4%, 8.0%, 7.5%, and 6.2% at 4, 8, 16, and 24 years of age, respectively. Between 8 and 24 years of age, (33/1565) participants developed IgE-ab to peanut extract (median 1,4, range 0.7-2.6 kU_A /L), and among those 85% were also sensitized to birch. Only six individuals developed sensitization to Ara h 2 (≥0.1 kU_A /L) between 8 and 24 years of age, of whom three had an IgE-ab level between 0.1-0.12 kU_A /L. Storage protein sensitization was associated with elevated FENO, blood eosinophils and type 2 inflammation-related systemic proteins.

CONCLUSION

Sensitization to peanut extract after 4 years of age is mainly induced by birch cross-sensitization and IgE to Ara h 2 rarely emerges after eight years of age. Storage protein sensitization is associated with respiratory and systemic inflammation.

Promising Therapeutic Functions of Bone Marrow Mesenchymal Stem Cells Derived-Exosome in Asthma

Asthma is a chronic inflammatory disturbance of the airways in which many cells and cellular elements are involved. Wheezing, breathlessness, chest tightness, and coughing, especially at night or in the early morning, are typical symptoms of asthma. At present, inhaled corticosteroid (ICS) and long-acting β-agonists (LABAs) are standard treatments for regular management. Oral corticosteroids (OCSs) were recommended for controlling asthma exacerbation but only for a short-term treatment because of the side effects on organs. Biologic therapies have achieved exciting and notable effects in clinical treatment but are not applicable for all phenotypes of asthma. At present, some new approaches are under exploration to lessen side effects and improve curative effects. Studies have revealed that bone marrow mesenchymal stem cells (BMMSCs) hold various curative effects in asthma and may benefit in the long term with high safety. Extracellular vesicles (EVs) enriched in body fluid were characterized as subcomponents of extracellular vesicles and delivered carriers combined with genetic messages in vivo. The therapeutic potential of exosomes has become a research hotspot in many diseases. BMMSC-derived exosomes were considered as the dominant part of BMMSCs in cell-to-cell communications and playing curative effects. Points also hold that BMMSC-Exo could interfere with airway inflammation and airway remolding in asthma via modulating the immune response, regulating gene expression, adjusting the phenotype of macrophage, etc. However, BMMSC-Exo still lacked more clinical trials for evaluating the effects on asthma, and the technology of extraction and purification still needs to be improved for wide use. This review aims to draw the relationship among asthma, BMMSC, and exosome, which may provide innovate ideas for treatment of asthma, and arouse attention about the curative potential of BMMSC-Exo.

Genetic effects of allergen-specific IgE levels on exhaled nitric oxide in schoolchildren with asthma: The STOPPA twin study

BACKGROUND

Exhaled nitric oxide and blood eosinophils are clinical asthma T-helper type 2 markers in use. Immunoglobulin E (IgE) is often involved in the inflammation associated with atopic asthma. The effect of both blood eosinophils and allergen-specific IgE on exhaled nitric oxide levels is not completely understood. Twin-design studies can improve understanding of the underlying contribution of genetically and/or environmentally driven inflammation markers in asthma. Our aim was to disentangle the covariance between asthma and exhaled nitric oxide into genetic and environmental contributions that can account for inflammation markers in a paediatric population.

METHODS

This population-based, cross-sectional twin study enrolled 612 monozygotic (MZ) and same-sex dizygotic (DZ) schoolchildren. Multivariate structural equation modelling was utilized to separate the covariance between asthma and exhaled nitric oxide into genetic and/or environmental effects, taking allergen-specific IgE level and blood eosinophil count into account while controlling for confounding factors.

RESULTS

The cross-twin/cross-trait correlations had a higher magnitude in the MZ twins than in the DZ twins, indicating that genes affect the association. The likelihood ratio test for model fitting resulted in the AE model (ie additive genetic effects, A, and non-shared environmental effects, E) as the most parsimonious. A majority, 73%, of the phenotypic correlation between asthma and exhaled nitric oxide, r = .19 (0.05-0.33), was attributable to genetic effects which mainly was due to the allergen-specific IgE level.

CONCLUSIONS

This study indicates that the association between asthma and exhaled nitric oxide in children is to a large extent explained by genetics via allergen-specific IgE level and not blood eosinophils. This might partly explain the clinical heterogeneity in this group. A next step could be to include allergen-specific IgE level in multivariate omic studies.