The nasal mucosal late allergic reaction to grass pollen involves type 2 inflammation (IL-5 and IL-13), the inflammasome (IL-1β), and complement

Differential modulation of allergic rhinitis nasal transcriptome by dupilumab and allergy immunotherapy

BACKGROUND

Nasal epithelial cells are important regulators of barrier function and immune signaling; however, in allergic rhinitis (AR) these functions can be disrupted by inflammatory mediators. We aimed to better discern AR disease mechanisms using transcriptome data from nasal brushing samples from individuals with and without AR.

METHODS

Data were drawn from a feasibility study of individuals with and without AR to Timothy grass and from a clinical trial evaluating 16 weeks of treatment with the following: dupilumab, a monoclonal antibody that binds interleukin (IL)-4Rα and inhibits type 2 inflammation by blocking signaling of both IL-4/IL-13; subcutaneous immunotherapy with Timothy grass (SCIT), which inhibits allergic responses through pleiotropic effects; SCIT + dupilumab; or placebo. Using nasal brushing samples from these studies, we defined distinct gene signatures in nasal tissue of AR disease and after nasal allergen challenge (NAC) and assessed how these signatures were modulated by study drug(s).

RESULTS

Treatment with dupilumab (normalized enrichment score [NES] = -1.73, p = .002) or SCIT + dupilumab (NES = -2.55, p < .001), but not SCIT alone (NES = +1.16, p = .107), significantly repressed the AR disease signature. Dupilumab (NES = -2.55, p < .001), SCIT (NES = -2.99, p < .001), and SCIT + dupilumab (NES = -3.15, p < .001) all repressed the NAC gene signature.

CONCLUSION

These results demonstrate type 2 inflammation is an important contributor to the pathophysiology of AR disease and that inhibition of the type 2 pathway with dupilumab may normalize nasal tissue gene expression.

Nasal IL-13 production identifies patients with late-phase allergic responses

BACKGROUND

There is limited knowledge on how local cytokine secretion patterns after nasal allergen challenge correlate with clinical symptoms especially with regard to the "late allergic response," which occurs in approximately 40% to 50% of patients with allergy.

OBJECTIVE

We sought to characterize the immunologic and clinical nasal responses to birch pollen allergen challenge with a special focus on the late allergic response.

METHODS

In this randomized, double-blind, placebo-controlled trial, birch pollen-allergic participants were challenged with birch pollen extract (n = 20) or placebo (n = 10) on 3 consecutive days. On days 1 and 3, nasal secretions were collected at selected time points over a 24-hour time course for the measurement of 33 inflammatory mediators. Clinical responses were determined through subjective symptom scores and objective nasal airflow measurements.

RESULTS

Provoked participants had significantly greater clinical responses and showed significant increases in tryptase and the soluble IL-33 receptor serum stimulation 2 (sST2) in nasal secretions within minutes compared with the placebo group. Eight of 20 provoked participants displayed high IL-13 levels 2 to 8 hours after allergen provocation. This group also showed significant changes in clinical parameters, with a secondary drop in nasal airflow measured by peak nasal inspiratory flow and increased symptoms of nasal obstruction, which significantly differed from IL-13 nonresponders after 6 hours.

CONCLUSIONS

IL-13 response status correlates with clinical responses and type 2 cytokine responses in the late phase after allergen provocation.

Integration of transcriptomics and metabolomics to reveal the effect of ginsenoside Rg3 on allergic rhinitis in mice

Increasing studies have demonstrated that ginsenoside Rg3 (Rg3) plays an important role in the prevention and treatment of various diseases, including allergic lower airway inflammation such as asthma. To investigate the role of Rg3 in allergic upper airway disease, the effect and therapeutic mechanism of Rg3 in allergic rhinitis (AR) were studied. Ovalbumin-induced AR model mice were intragastrically administered with Rg3. Nasal symptoms, levels of IgE, IL-4, IL-5, IL-13, SOD and MDA in serum, and histopathological analysis of nasal mucosa were used to evaluate the effect of Rg3 on ameliorating AR in mice. Moreover, nasal mucosa samples from the normal control group, AR model group and high dosage of Rg3 were collected to perform omics analysis. The differentially expressed genes and significantly changed metabolites were screened based on transcriptomics and metabolomics analyses, respectively. Integrative analysis was further performed to confirm the hub genes, metabolites and pathways. After Rg3 intervention, the nasal symptoms and inflammatory infiltration were effectively improved, the levels of IgE, IL-4, IL-5, IL-13 and MDA were significantly reduced, and the level of SOD was obviously increased. The results of the qRT-PCR assay complemented the transcriptomic findings. Integrated analysis showed that Rg3 played an anti-AR role mainly by regulating the interaction network, which was constructed by 12 genes, 8 metabolites and 4 pathways. Our findings suggested that Rg3 had a therapeutic effect on ovalbumin-induced AR in mice by inhibiting inflammation development and reducing oxidative stress. The present study could provide a potential natural agent for the treatment of AR.

The nasal microbiome in patients suffering from non-steroidal anti-inflammatory drugs-exacerbated respiratory disease in absence of corticosteroids

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease phenotypically classified by the absence (CRSsNP) or presence of nasal polyps (CRSwNP). The latter may also be associated with asthma and hypersensitivity towards non-steroidal anti-inflammatory drugs (NSAID) as a triad termed NSAID-exacerbated respiratory disease (N-ERD). The role of the microbiome in these different disease entities with regard to the underlying inflammatory process and disease burden is yet not fully understood. To address this question, we measured clinical parameters and collected nasal samples (nasal mucosal fluids, microbiome swabs from middle meatus and anterior naris) of patients suffering from CRSsNP (n=20), CRSwNP (n=20) or N-ERD (n=20) as well as from patients without CRS (=disease controls, n=20). Importantly, all subjects refrained from taking local or systemic corticosteroids or immunosuppressants for at least two weeks prior to sampling. The nasal microbiome was analyzed using 16S rRNA gene amplicon sequencing, and levels of 33 inflammatory cytokines were determined in nasal mucosal fluids using the MSD platform. Patients suffering from N-ERD and CRSwNP showed significantly worse smell perception and significantly higher levels of type 2 associated cytokines IL-5, IL-9, Eotaxin and CCL17. Across all 4 patient groups, Corynebacteria and Staphylococci showed the highest relative abundances. Although no significant difference in alpha and beta diversity was observed between the control and the CRS groups, pairwise testing revealed a higher relative abundance of Staphylococci in the middle meatus in N-ERD patients as compared to CRSwNP (p<0.001), CRSsNP (p<0.01) and disease controls (p<0.05) and of Lawsonella in patients suffering from CRSwNP in middle meatus and anterior naris in comparison to CRSsNP (p<0.0001 for both locations) and disease controls (p<0.01 and p<0.0001). Furthermore, we observed a positive correlation of Staphylococci with IL-5 (Pearson r=0.548) and a negative correlation for Corynebacteria and Eotaxin-3 (r=-0.540). Thus, in patients refraining from oral and nasal corticosteroid therapy for at least two weeks known to alter microbiome composition, we did not observe differences in microbiome alpha or beta diversity between various CRS entities and disease controls. However, our data suggest a close association between increased bacterial colonization with Staphylococci and decreased colonization by Corynebacteria as well as increased type 2 inflammation.

Multiplex Hybrid Antigen-Capture LC-MRM Quantification in Sera and Nasal Lining Fluid of AZD7442, a SARS-CoV-2-Targeting Antibody Combination

AZD7442 (tixagevimab [AZD8895]/cilgavimab [AZD1061]) is a monoclonal antibody (mAb) combination in development for the prevention and treatment of coronavirus disease 2019. Traditionally, bioanalysis of mAbs is performed using ligand binding assays (LBAs), which offer sensitivity, robustness, and ease of implementation. However, LBAs frequently require generation of critical reagents that typically take several months. Instead, we developed a highly sensitive (5 ng/mL limit of quantification) method using a hybrid LBA-liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) approach for quantification of the two codosed antibodies in serum and nasal lining fluid (NLF), a rare matrix. The method was optimized by careful selection of multiple reaction monitoring, capture reagents, magnetic beads, chromatographic conditions, evaluations of selectivity, and matrix effect. The final assay used viral spike protein receptor-binding domain as capture reagent and signature proteotypic peptides from the complementarity-determining region of each mAb for detection. In contrast to other methods of similar/superior sensitivity, our approach did not require multidimensional separations and can be operated in an analytical flow regime, ensuring high throughput and robustness required for clinical analysis at scale. The sensitivity of this method significantly exceeds typical sensitivity of ∼100 ng/mL for analytical flow 1D LBA-LC-MS/MS methods for large macromolecules, such as antibodies. Furthermore, infection and vaccination status did not impact method performance, ensuring method robustness and applicability to a broad patient population. This report demonstrated the general applicability of the hybrid LBA-LC-MS/MS approach to platform quantification of antibodies with high sensitivity and reproducibility, with specialized extension to matrices of increasing interest, such as NLF.

Pathways linked to unresolved inflammation and airway remodelling characterize the transcriptome in two independent severe asthma cohorts

Background and objective

Severe asthma (SA) is a heterogeneous disease. Transcriptomic analysis contributes to the understanding of pathogenesis necessary for developing new therapies. We sought to identify and validate mechanistic pathways of SA across two independent cohorts.

Methods

Transcriptomic profiles from U‐BIOPRED and Australian NOVocastrian Asthma cohorts were examined and grouped into SA, mild/moderate asthma (MMA) and healthy controls (HCs). Differentially expressed genes (DEGs), canonical pathways and gene sets were identified as central to SA mechanisms if they were significant across both cohorts in either endobronchial biopsies or induced sputum.

Results

Thirty‐six DEGs and four pathways were shared across cohorts linking to tissue remodelling/repair in biopsies of SA patients, including SUMOylation, NRF2 pathway and oxidative stress pathways. MMA presented a similar profile to HCs. Induced sputum demonstrated IL18R1 as a shared DEG in SA compared with healthy subjects. We identified enrichment of gene sets related to corticosteroid treatment; immune‐related mechanisms; activation of CD4⁺ T cells, mast cells and IL18R1; and airway remodelling in SA.

Conclusion

Our results identified differentially expressed pathways that highlight the role of CD4⁺ T cells, mast cells and pathways linked to ongoing airway remodelling, such as IL18R1, SUMOylation and NRF2 pathways, as likely active mechanisms in the pathogenesis of SA.

Transcriptome analysis from endobronchial biopsies and induced sputum from two independent cohorts of adults with severe asthma (SA) (U‐BIOPRED and Australian NOVocastrian Asthma cohort) demonstrated shared differentially expressed pathways previously linked to persistent unresolved inflammation and novel mechanisms of airway remodelling, which may represent potential novel mechanistic pathways involved in the pathogenesis of SA.

See relatededitorial

Comprehensive Analysis of Nasal Polyps Reveals a More Pronounced Type 2 Transcriptomic Profile of Epithelial Cells and Mast Cells in Aspirin-Exacerbated Respiratory Disease

Chronic rhinosinusitis with nasal polyps is affecting up to 3% of Western populations. About 10% of patients with nasal polyps also suffer from asthma and intolerance to aspirin, a syndrome called aspirin-exacerbated respiratory disease. Although eosinophilic inflammation is predominant in polyps of both diseases, phenotypic differences in the tissue-derived microenvironment, elucidating disease-specific characteristics, have not yet been identified. We sought to obtain detailed information about phenotypic and transcriptional differences in epithelial and immune cells in polyps of aspirin-tolerant and intolerant patients. Cytokine profiles in nasal secretions and serum of patients suffering from aspirin-exacerbated respiratory disease (n = 10) or chronic rhinosinusitis with nasal polyps (n = 9) were assessed using a multiplex mesoscale discovery assay. After enrichment for immune cell subsets by flow cytometry, we performed transcriptomic profiling by employing single-cell RNA sequencing. Aspirin-intolerant patients displayed significantly elevated IL-5 and CCL17 levels in nasal secretions corresponding to a more pronounced eosinophilic type 2 inflammation. Transcriptomic profiling revealed that epithelial and mast cells not only complement one another in terms of gene expression associated with the 15-lipoxygenase pathway but also show a clear type 2-associated inflammatory phenotype as identified by the upregulation of POSTN, CCL26, and IL13 in patients with aspirin-exacerbated respiratory disease. Interestingly, we also observed cellular stress responses indicated by an increase of MTRNR2L12, MTRNR2L8, and NEAT1 across all immune cell subsets in this disease entity. In conclusion, our findings support the hypothesis that epithelial and mast cells act in concert as potential drivers of the pathogenesis of the aspirin-exacerbated respiratory disease.

Ameliorating Atopy by Compensating Micronutritional Deficiencies in Immune Cells: A Double-Blind Placebo-Controlled Pilot Study

BACKGROUND

Functional iron deficiency facilitates allergy development and amplifies the symptom burden in people experiencing allergies. Previously we selectively delivered micronutrients to immune cells with β-lactoglobulin as carrier (holoBLG), resulting in immune resilience and allergy prevention.

OBJECTIVE

The clinical efficacy of a food for special medical purposes-lozenge containing β-lactoglobulin with iron, polyphenols, retinoic acid, and zinc (holoBLG lozenge) was assessed in allergic women.

METHODS

In a randomized, double-blind, placebo-controlled pilot study, grass- and/or birch pollen-allergic women (n = 51) were given holoBLG or placebo lozenges over 6 months. Before and after dietary supplementation, participants were nasally challenged and the blood was analyzed for immune and iron parameters. Daily symptoms, medications, pollen concentrations, and well-being were recorded by an electronic health application.

RESULTS

Total nasal symptom score after nasal provocations improved by 42% in the holoBLG group versus 13% in the placebo group. The combined symptom medication score during the birch peak and entire season as well as the entire grass pollen season improved in allergic subjects supplemented with the holoBLG lozenge by 45%, 31%, and 40%, respectively, compared with the placebo arm. Participants ingesting the holoBLG lozenge had improved iron status with increased hematocrit values, decreased red cell distribution width, and higher iron levels in circulating CD14⁺ cells compared with the placebo group.

CONCLUSIONS

Targeted micronutrition with the holoBLG lozenge seemed to be effective in elevating the labile iron levels in immune cells and reducing the symptom burden in allergic women in this pilot study. The underlying allergen-independent mechanism provides evidence that dietary nutritional supplementation of the immune system is one of the ways to combat atopy.

The role of properdin and Factor H in disease

The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.

Comparison of Overall Immunity Levels among Workers at Grape Orchard, Rose Greenhouse, and Open-Field Onion Farm

Background

Methods

Results

Conclusion

Role of C5a and C5aR in doxorubicin-induced cardiomyocyte senescence

Doxorubicin (DOX) is an efficacious antineoplastic drug; however, its use is limited due to its cardiotoxicity. Cardiomyocyte senescence is considered to be a key factor in the development of DOX-related cardiomyopathy. Complement component 5a (C5a) and the C5a receptor (C5aR) have been reported to play a key role in the process of cellular senescence. However, to the best of our knowledge, the exact role of C5a and C5aR in cellular senescence in the heart remains largely unknown. Reverse transcription-quantitative (RT-q)PCR and western blot assays were used to analyze the expression levels of C5a and C5aR in H9c2 embryonic rat cardiomyocytes and AC16 human cardiomyocyte-like cells. The cells were treated with DOX and a C5aR antagonist (C5aRA). The expression of TNF-α and IFN-γ was determined using ELISA and western blotting. The levels of reactive oxygen species (ROS) were also measured using ELISA. Cellular senescence was determined using senescence-associated β-galactosidase (SA-β-gal) staining and by analyzing the protein expression levels of p53, p16, p21 and insulin-like growth factor-binding protein 3 (IGFBP3). The expression levels of C5a and C5aR were found to be upregulated during the DOX-induced senescence of H9c2 and AC16 cardiomyocytes. Treatment with C5aRA downregulated TNF-α and IFN-γ expression, in addition to ROS levels. Furthermore, C5aRA prevented DOX-induced cellular senescence and decreased the levels of positive SA-β-gal staining in H9c2 and AC16 cardiomyocytes, in addition to downregulating the expression levels of p53, p16, p21 and IGFBP3. C5aRA also increased the telomere length and telomerase activity in H9c2 and AC16 cardiomyocytes following DOX stimulation. In conclusion, the findings of the present study indicated that C5a and C5aR may play a key role in cardiomyocyte senescence, and treatment with C5aRA may be an effective method for preventing DOX-induced cardiomyocyte aging.

Effect of intranasal corticosteroid treatment on allergen-induced changes in group 2 innate lymphoid cells in allergic rhinitis with mild asthma

BACKGROUND

Allergic rhinitis is characterized by rhinorrhea, nasal congestion, sneezing and nasal pruritus. Group 2 innate lymphoid cells (ILC2s), CD4⁺ T cells and eosinophils in nasal mucosa are increased significantly after nasal allergen challenge (NAC). Effects of intranasal corticosteroids (INCS) on ILC2s remain to be investigated.

METHODS

Subjects (n = 10) with allergic rhinitis and mild asthma were enrolled in a single-blind, placebo-controlled, sequential treatment study and treated twice daily with intranasal triamcinolone acetonide (220 µg) or placebo for 14 days, separated by a 7-day washout period. Following treatment, subjects underwent NAC and upper airway function was assessed. Cells from the nasal mucosa and blood, sampled 24 h post-NAC, underwent flow cytometric enumeration for ILC2s, CD4⁺ T and eosinophil progenitor (EoPs) levels. Cell differentials and cytokine levels were assessed in nasal lavage.

RESULTS

Treatment with INCS significantly attenuated ILC2s, IL-5⁺ /IL-13⁺ ILC2s, HLA-DR⁺ ILC2s and CD4⁺ T cells in the nasal mucosa, 24 h post-NAC. EoP in nasal mucosa was significantly increased, while mature eosinophils were significantly decreased, 24 h post-NAC in INCS versus placebo treatment arm. Following INCS treatment, IL-2, IL-4, IL-5 and IL-13 were significantly attenuated 24 h post-NAC accompanied by significant improvement in upper airway function.

CONCLUSION

Pre-treatment with INCS attenuates allergen-induced increases in ILC2s, CD4⁺ T cells and terminal differentiation of EoPs in the nasal mucosa of allergic rhinitis patients with mild asthma, with little systemic effect. Attenuation of HLA-DR expression by ILC2s may be an additional mechanism by which steroids modulate adaptive immune responses in the upper airways.

The Similarity of Biomarkers Level between Direct Nasal Fluid and Nasal Lavage Fluid in Allergic Rhinitis Patients

Background and Objectives: Biomarkers of allergic rhinitis (AR) have been studied; however, little is known regarding their practical application in the diagnosis of AR. Previous studies collected samples using saline lavage, nasal brushing, or nasal biopsy. To utilize nasal fluid as a diagnostic tool, we need to standardize the method of sample collection. Therefore, this study aimed to evaluate the difference in concentration of biomarkers depending on the method of nasal fluid collection.Materials and Method: Forty-five AR patients who had greater than moderate AR symptoms and who had positive results on skin prick test and serum-specific IgE tests were enrolled in this study. Nasal fluid was collected using the direct method or saline lavage method. The concentration of each biomarker was analyzed using enzyme-linked immunosorbent assay and the values compared.Results: Nasal fluid samples were collected directly from 14 patients and were collected via saline lavage in 31 patients. No significant differences were found in the median value of each biomarker between the two methods of nasal sample collection.Conclusion: Nasal fluid collection method does not significantly affect biomarker concentration.

Alternative Pathway Involvement in Protoporphyria Patients Related to Sun Exposure

The homeostasis of tissues in a chronic disease is an essential function of the alternative pathway (AP) of the complement system (CS). However, if not controlled, it may also be detrimental to healthy cells with a consequent aggravation of symptoms. The protoporphyria (PP) is a rare chronic disease that causes phototoxicity in visible light with local skin pain and general malaise. In order to establish if there is a systemic involvement of the CS during sun exposure, we designed a non-invasive method with a serum collection in winter and summer from 19 PP and 13 controls to detect the levels of CS protein: Properdin, Factor H (FH), and C5. Moreover, the global radiation data were collected from the regional agency of environmental protection (ARPA). The results show growing values for every protein in patients with PP, compared to control, in both seasons, in particular in summer compared to winter. To reinforce the evidence, we have estimated the personal exposure of patients based on the global radiation data. The main factors of the AP increased over the season, confirming the involvement of the AP in relation to light exposure. The systemic response could justify the general malaise of patients after long light exposure and can be exploited to elucidate new therapeutic approaches.

Experimental Human Challenge Defines Distinct Pneumococcal Kinetic Profiles and Mucosal Responses between Colonized and Non-Colonized Adults

Colonization of the upper respiratory tract with Streptococcus pneumoniae is the precursor of pneumococcal pneumonia and invasive disease. Following exposure, however, it is unclear which human immune mechanisms determine whether a pathogen will colonize. We used a human challenge model to investigate host-pathogen interactions in the first hours and days following intranasal exposure to Streptococcus pneumoniae Using a novel home sampling method, we measured early immune responses and bacterial density dynamics in the nose and saliva after volunteers were experimentally exposed to pneumococcus. Here, we show that nasal colonization can take up to 24 h to become established. Also, the following two distinct bacterial clearance profiles were associated with protection: nasal clearers with immediate clearance of bacteria in the nose by the activity of pre-existent mucosal neutrophils and saliva clearers with detectable pneumococcus in saliva at 1 h post challenge and delayed clearance mediated by an inflammatory response and increased neutrophil activity 24 h post bacterial encounter. This study describes, for the first time, how colonization with a bacterium is established in humans, signifying that the correlates of protection against pneumococcal colonization, which can be used to inform design and testing of novel vaccine candidates, could be valid for subsets of protected individuals.IMPORTANCE Occurrence of lower respiratory tract infections requires prior colonization of the upper respiratory tract with a pathogen. Most bacterial infection and colonization studies have been performed in murine and in vitro models due to the current invasive sampling methodology of the upper respiratory tract, both of which poorly reflect the complexity of host-pathogen interactions in the human nose. Self-collecting saliva and nasal lining fluid at home is a fast, low-cost, noninvasive, high-frequency sampling platform for continuous monitoring of bacterial encounter at defined time points relative to exposure. Our study demonstrates for the first time that, in humans, there are distinct profiles of pneumococcal colonization kinetics, distinguished by speed of appearance in saliva, local phagocytic function, and acute mucosal inflammatory responses, which may either recruit or activate neutrophils. These data are important for the design and testing of novel vaccine candidates.

Mechanisms of Allergen Immunotherapy in Allergic Rhinitis

PURPOSE OF REVIEW

Allergic rhinitis (AR) is a chronic inflammatory immunoglobulin (Ig) E-mediated disease of the nasal mucosa that can be triggered by the inhalation of seasonal or perennial allergens. Typical symptoms include sneezing, rhinorrhea, nasal itching, nasal congestion and symptoms of allergic conjunctivitis. AR affects a quarter of the population in the United States of America and Europe.

RECENT FINDINGS

AR has been shown to reduce work productivity in 36-59% of the patients with 20% reporting deteriorated job attendance. Moreover, 42% of children with AR report reduced at-school productivity and lower grades. Most importantly, AR impacts the patient's quality of life, due to sleep deprivation. However, a proportion of patients fails to respond to conventional medication and opts for the allergen immunotherapy (AIT), which currently is the only disease-modifying therapeutic option. AIT can be administered by either subcutaneous (SCIT) or sublingual (SLIT) route. Both routes of administration are safe, effective, and can lead to tolerance lasting years after treatment cessation. Both innate and adaptive immune responses that contribute to allergic inflammation are suppressed by AIT. Innate responses are ameliorated by reducing local mast cell, basophil, eosinophil, and circulating group 2 innate lymphoid cell frequencies which is accompanied by decreased basophil sensitivity. Induction of allergen-specific blocking antibodies, immunosuppressive cytokines, and regulatory T and B cell phenotypes are key pro-tolerogenic adaptive immune responses.

CONCLUSION

A comprehensive understanding of these mechanisms is necessary for optimal selection of AIT-responsive patients and monitoring treatment efficacy. Moreover, it could inspire novel and more efficient AIT approaches.

Repetitive nasal allergen challenge in allergic rhinitis: Priming and Th2-type inflammation but no evidence of remodelling

BACKGROUND

Local tissue eosinophilia and Th2 cytokines are characteristic features of seasonal allergic rhinitis. Airway remodelling is a feature of asthma whereas evidence for remodelling in allergic rhinitis (AR) is conflicting.

OBJECTIVE

By use of a novel human repetitive nasal allergen challenge (RAC) model, we evaluated the relationship between allergic inflammation and features of remodelling in AR.

METHODS

Twelve patients with moderate-severe AR underwent 5 alternate day challenges with diluent which after 4 weeks were followed by 5 alternate day challenges with grass pollen extract. Nasal symptoms, Th1/Th2 cytokines in nasal secretion and serum were evaluated. Nasal biopsies were taken 24 hours after the 1st and 5th challenges with diluent and with allergen. Sixteen healthy controls underwent a single challenge with diluent and with allergen. Using immunohistochemistry, epithelial and submucosal inflammatory cells and remodelling markers were evaluated by computed image analysis.

RESULTS

There was an increase in early and late-phase symptoms after every allergen challenge compared to diluent (both P < .05) with evidence of both clinical and immunological priming. Nasal tissue eosinophils and IL-5 in nasal secretion increased significantly after RAC compared to corresponding diluent challenges (P < .01, P = .01, respectively). There was a correlation between submucosal mast cells and the early-phase clinical response (r = 0.79, P = .007) and an association between epithelial eosinophils and IL-5 concentrations in nasal secretion (r = 0.69, P = .06) in allergic rhinitis. No differences were observed after RAC with regard to epithelial integrity, reticular basement membrane thickness, glandular area, expression of markers of activation of airway remodelling including α-SMA, HSP-47, extracellular matrix (MMP7, 9 and TIMP-1), angiogenesis and lymphangiogenesis for AR compared with healthy controls.

CONCLUSION

Novel repetitive nasal allergen challenge in participants with severe persistent seasonal allergic rhinitis resulted in tissue eosinophilia and increases in IL-5 but no structural changes. Our data support no link between robust Th2-inflammation and development of airway remodelling in AR.

Circadian Clock and Complement Immune System-Complementary Control of Physiology and Pathology?

Mammalian species contain an internal circadian (i.e., 24-h) clock that is synchronized to the day and night cycles. Large epidemiological studies, which are supported by carefully controlled studies in numerous species, support the idea that chronic disruption of our circadian cycles results in a number of health issues, including obesity and diabetes, defective immune response, and cancer. Here we focus specifically on the role of the complement immune system and its relationship to the internal circadian clock system. While still an incompletely understood area, there is evidence that dysregulated proinflammatory cytokines, complement factors, and oxidative stress can be induced by circadian disruption and that these may feed back into the oscillator at the level of circadian gene regulation. Such a feedback cycle may contribute to impaired host immune response against pathogenic insults. The complement immune system including its activated anaphylatoxins, C3a and C5a, not only facilitate innate and adaptive immune response in chemotaxis and phagocytosis, but they can also amplify chronic inflammation in the host organism. Consequent development of autoimmune disorders, and metabolic diseases associated with additional environmental insults that activate complement can in severe cases, lead to accelerated tissue dysfunction, fibrosis, and ultimately organ failure. Because several promising complement-targeted therapeutics to block uncontrolled complement activation and treat autoimmune diseases are in various phases of clinical trials, understanding fully the circadian properties of the complement system, and the reciprocal regulation by these two systems could greatly improve patient treatment in the long term.

3β-Hydroxycholest-5-en-7-one from seahorse alleviates lipopolysaccharide-induced inflammatory responses by downregulating miR-98-5p

AIMS

We investigated the anti-inflammatory activity of 3β-hydroxycholest-5-en-7-one from Hippocampus trimaculatus leach and provided a theoretical basis for identifying its therapeutic targets.

MAIN METHODS

Small-RNA libraries were constructed for untreated control RAW 264.7 cells and cells treated with lipopolysaccharide (LPS; 1.0 μg/mL) or 10 μM 3β-hydroxycholest-5-en-7-one +1.0 μg/mL LPS. We constructed and tested a miR-98-5p-interfering lentivirus to evaluate the role of miR-98-5p in the 3β-hydroxycholest-5-en-7-one-dependent regulation of inflammatory responses in LPS-induced macrophage and murine inflammation models. The small-RNA libraries were analyzed using high-throughput sequencing.

KEY FINDINGS

Among the differentially expressed microRNAs, miR-98-5p showed the most significant difference. Bioinformatics tools were used to identify the potential regulatory targets of miR-98-5p, which were tested using dual-luciferase reporter assays. Our results demonstrated that 3β-hydroxycholest-5-en-7-one exerted an anti-inflammatory effect via miR-98-5p, which negatively regulated the expression of its target gene TNFAIP3. The results indicate that miR-98-5p interference and 3β-hydroxycholest-5-en-7-one treatment significantly upregulated the low TNFAIP3 expression induced by LPS stimulation, thereby inhibiting TRAF6, RIP, NF-κB, IL-1β, and TNF-α secretion.

SIGNIFICANCE

3β-Hydroxycholest-5-en-7-one alleviates inflammation by downregulating miR-98-5p and upregulating TNFAIP3, thereby blocking NF-κB pathway activation. These results reveal the specific anti-inflammatory mechanism of 3β-hydroxycholest-5-en-7-one, providing a foundation for developing new drugs and identifying drug targets.

Mesenchymal Stem Cell-Based Therapy for Allergic Rhinitis

Allergic rhinitis (AR) is a prevalent disorder that causes a significant and often underestimated health burden for individuals and society. The current drug treatment cannot essentially deal with the regulation of the allergic reaction, while the allergic symptoms could be alleviated. Mesenchymal stem cells (MSCs) bear a variety of properties, such as the ability to differentiate into various cell lineages, to secrete soluble factors crucial for cell survival and proliferation, to migrate to the exact site of injury, and to modulate the immune response. Clinical studies have been extensively conducted in MSCs as the models for varieties of diseases such as neurological diseases. Due to their immunomodulatory properties, the MSCs have gradually been believed to become one of the promising strategies for AR treatments although so far the MSCs-mediated treatment for AR is still at animal experiments stage. Fully understanding the roles and mechanisms of MSCs immunomodulatory effects serves as the prerequisite that will be beneficial to the application of MSCs-based AR clinical treatment methods. In this review article, we highlighted the recent research advances and give a brief perspective in the future study of the MSCs-mediated therapeutic application in AR treatments.

Immune Profile of the Nasal Mucosa in Patients with Cutaneous Leishmaniasis

Localized skin lesions are characteristic of cutaneous leishmaniasis (CL); however, Leishmania (Viannia) species, which are responsible for most CL cases in the Americas, can spread systemically, sometimes resulting in mucosal disease. Detection of Leishmania has been documented in healthy mucosal tissues (conjunctiva, tonsils, and nasal mucosa) and healthy skin of CL patients and in individuals with asymptomatic infection in areas of endemicity of L (V) panamensis and L (V) braziliensis transmission. However, the conditions and mechanisms that favor parasite persistence in healthy mucosal tissues are unknown. In this descriptive study, we compared the cell populations of the nasal mucosa (NM) of healthy donors and patients with active CL and explored the immune gene expression signatures related to molecular detection of Leishmania in this tissue in the absence of clinical signs or symptoms of mucosal disease. The cellular composition and gene expression profiles of NM samples from active CL patients were similar to those of healthy volunteers, with a predominance of epithelial over immune cells, and within the CD45⁺ cell population, a higher frequency of CD66b⁺ followed by CD14⁺ and CD3⁺ cells. In CL patients with molecular evidence of Leishmania persistence in the NM, genes characteristic of an anti-inflammatory and tissue repair responses (IL4R, IL5RA, POSTN, and SATB1) were overexpressed relative to NM samples from CL patients in which Leishmania was not detected. Here, we report the first immunological description of subclinically infected NM tissues of CL patients and provide evidence of a local anti-inflammatory environment favoring parasite persistence in the NM.

Physical and immunological barrier of human primary nasal epithelial cells from non-allergic and allergic donors

The epithelial cell-derived cytokine milieu has been discussed as a “master switch” in the development of allergic disease.

To understand the role of innate immune response in nasal epithelial cells during allergic inflammation, we created and established a fast and minimally invasive method to isolate and culture human nasal epithelial cells from clinically and immunologically well characterized patients. Human nasal epithelial cells from non-atopic volunteers and from allergic rhinitis patients were compared in respect to their growth, barrier integrity, pattern recognition, receptor expression, and immune responses to allergens and an array of pathogen-associated molecular patterns and inflammasome activators.

Cells from nasal scrapings were clearly identified as nasal epithelial cells by staining of pan-Cytokeratin, Cytokeratin-14 and Tubulin. Additionally, Mucin 5AC staining revealed the presence of goblet cells, while staining of tight-junction protein Claudin-1, Occludin and ZO-1 showed the ability of the cells to form a tight barrier. Cells of atopic donors grew slower than cells of non-atopic donors. All nasal epithelial cells expressed TLR1-6 and 9, yet the expression of TLR-9 was lower in cells from allergic rhinitis (AR) donors. Additionally, epithelial cells from AR donors responded with a different TLR expression pattern to stimulation with TLR ligands. TLR-3 was the most potent modulator of cytokine and chemokine secretion in all human nasal epithelial cells (HNECs). The secretion of IL-1β, CCL-5, IL-8, IL-18 and IL-33 was elevated in HNECs of AR donors as compared to cells of non-atopic donors. This was observed in the steady-state (IL-18, IL-33) as well as under stimulation with TLR ligands (IL-18, IL-33, CCL-5, IL-8), aqueous pollen extracts (IL-18, IL-33), or the inflammasome activator Nigericin (IL-1β).

In conclusion, nasal epithelial cells of AR donors show altered physical barrier responses in steady-state and in response to allergen stimulation. Cells of AR donors show increased expression of pro-inflammatory and IL-1 family cytokines at baseline and under stimulation, which could contribute to a micromilieu which is favorable for Th2.

Systems biology and big data in asthma and allergy: recent discoveries and emerging challenges

Asthma is a common condition caused by immune and respiratory dysfunction, and it is often linked to allergy. A systems perspective may prove helpful in unravelling the complexity of asthma and allergy. Our aim is to give an overview of systems biology approaches used in allergy and asthma research. Specifically, we describe recent "omic"-level findings, and examine how these findings have been systematically integrated to generate further insight.Current research suggests that allergy is driven by genetic and epigenetic factors, in concert with environmental factors such as microbiome and diet, leading to early-life disturbance in immunological development and disruption of balance within key immuno-inflammatory pathways. Variation in inherited susceptibility and exposures causes heterogeneity in manifestations of asthma and other allergic diseases. Machine learning approaches are being used to explore this heterogeneity, and to probe the pathophysiological patterns or "endotypes" that correlate with subphenotypes of asthma and allergy. Mathematical models are being built based on genomic, transcriptomic and proteomic data to predict or discriminate disease phenotypes, and to describe the biomolecular networks behind asthma.The use of systems biology in allergy and asthma research is rapidly growing, and has so far yielded fruitful results. However, the scale and multidisciplinary nature of this research means that it is accompanied by new challenges. Ultimately, it is hoped that systems medicine, with its integration of omics data into clinical practice, can pave the way to more precise, personalised and effective management of asthma.

Mesenchymal stem cells in allergic diseases: Current status

Allergic diseases, which include asthma, allergic skin diseases, allergic rhinitis and allergic conjunctivitis, have already garnered worldwide public health attention over recent decades. Mesenchymal stem cells (MSCs) have gradually emerged as a potential method for treating allergic diseases due to their immunosuppressive characteristics, tissue repair ability and secretion of various biological factors. This potential of MSC-based therapy has been confirmed in clinical and preclinical studies, which report the therapeutic benefits of MSCs for various allergic diseases and explore the antiallergic mechanisms. In this review, we focus on the discoveries and biological mechanisms of MSCs as a therapeutic tool in allergic diseases. We discuss the challenges of conducting MSC studies as well as future directions.

Patterns of systemic and local inflammation in patients with asthma hospitalised with influenza

BACKGROUND

Patients with asthma are at risk of hospitalisation with influenza, but the reasons for this predisposition are unknown.

STUDY SETTING

A prospective observational study of adults with PCR-confirmed influenza in 11 UK hospitals, measuring nasal, nasopharyngeal and systemic immune mediators and whole-blood gene expression.

RESULTS

Of 133 admissions, 40 (30%) had previous asthma; these were more often female (70% versus 38.7%, OR 3.69, 95% CI 1.67-8.18; p=0.0012), required less mechanical ventilation (15% versus 37.6%, Chi-squared 6.78; p=0.0338) and had shorter hospital stays (mean 8.3 versus 15.3 days, p=0.0333) than those without. In patients without asthma, severe outcomes were more frequent in those given corticosteroids (OR 2.63, 95% CI 1.02-6.96; p=0.0466) or presenting >4 days after disease onset (OR 5.49, 95% CI 2.28-14.03; p=0.0002). Influenza vaccination in at-risk groups (including asthma) were lower than intended by national policy and the early use of antiviral medications were less than optimal. Mucosal immune responses were equivalent between groups. Those with asthma had higher serum interferon (IFN)-α, but lower serum tumour necrosis factor, interleukin (IL)-5, IL-6, CXCL8, CXCL9, IL-10, IL-17 and CCL2 levels (all p<0.05); both groups had similar serum IL-13, total IgE, periostin and blood eosinophil gene expression levels. Asthma diagnosis was unrelated to viral load, IFN-α, IFN-γ, IL-5 or IL-13 levels.

CONCLUSIONS

Asthma is common in those hospitalised with influenza, but may not represent classical type 2-driven disease. Those admitted with influenza tend to be female with mild serum inflammatory responses, increased serum IFN-α levels and good clinical outcomes.

Clockwork allergy: How the circadian clock underpins allergic reactions

Allergic disease is characterized by marked day-night changes in the clinical symptoms and laboratory parameters of allergy. Recent reports suggest that the circadian clock, which drives a biological rhythm with a periodicity of approximately 24 hours in behavior and physiology, underpins a time of day-dependent variation in allergic reactions. New studies also suggest that disruption of clock activity not only influences temporal variation but can also enhance the severity of allergic reactions and even increase susceptibility to allergic disease. These findings suggest that the circadian clock is a potent regulator of allergic reactions that plays more than a simple circadian timekeeping role in allergy. A better understanding of these processes will provide new insight into previously unknown aspects of the biology of allergies and can lead to the application of clock modifiers to treat allergic disease. Finally, this area of research provides a novel opportunity to consider how modern lifestyles in the developed world are changing the clinical manifestations of allergy as our society quickly transforms into a circadian rhythm-disrupted society in which sleeping, working, and eating habits are out of sync with endogenous circadian rhythmicity. Such findings might reveal lifestyle interventions that enable us to better control allergic disease.

T-cell-derived cytokines enhance the antigen-presenting capacity of human neutrophils

Activated allergen‐specific Th2 and Th1 cells release cytokines that transform neutrophils into functional APCs characterized by the expression of HLA‐DR and CD58 as well as enhanced survival and antigen uptake, irrespectively of the presence of IL‐10, which reduces allergen uptake by neutrophils.

Matrix Metalloproteinase-9-Dependent Release of IL-1β by Human Eosinophils

Asthma is often associated with airway eosinophilia, and therapies targeting eosinophils are now available to treat severe eosinophilic asthma. Eosinophilic asthma is often due to a type-2 immune response and production of IL-5, which leads to eosinophilopiesis and recruitment of mature eosinophils in the airways. A concomitant type-2 and type-17 response has been reported in some individuals. IL-17 may be enhanced by IL-1β production and can lead to neutrophilic inflammation. In fact, both eosinophilic and neutrophilic (mixed granulocytic) inflammation are simultaneously present in a large population of patients with asthma. In monocyte/macrophage cell populations, release of mature IL-1β occurs via toll-like receptor ligand-induced activation of the inflammasome. Within the inflammasome, a cascade of events leads to the activation of caspase-1, which cleaves pro-IL-1β protein into a mature, releasable, and active form. We have demonstrated that eosinophils can release IL-1β in a Toll-like receptor ligand-independent fashion. The objective of this study was to determine the mechanisms underlying the production and maturation of IL-1β in cytokine-activated eosinophils. Using eosinophils from circulating blood and from bronchoalveolar lavage fluid after an airway allergen challenge, the present study demonstrates that cytokine-activated eosinophils express and release a bioactive form of IL-1β with an apparent size less than the typical 17 kDa mature form produced by macrophages. Using a zymography approach and pharmacological inhibitors, we identified matrix metalloproteinase-9 (MMP-9) as a protease that cleaves pro-IL-1β into a ~15 kDa form and allows the release of IL-1β from cytokine-activated eosinophils. Therefore, we conclude that activated eosinophils produce MMP-9, which causes the release of IL-1β in an inflammasome/caspase-1-independent manner. The production of IL-1β by eosinophils may be a link between the eosinophilic/type-2 immune response and the neutrophilic/type-17 immune response that is often associated with a more severe and treatment-refractory type of asthma.

Human Adipose Tissue-Derived Mesenchymal Stem Cells Attenuate Atopic Dermatitis by Regulating the Expression of MIP-2, miR-122a-SOCS1 Axis, and Th1/Th2 Responses

The objective of this study was to investigate the effect of human adipose tissue-derived mesenchymal stem cells (AdMSCs) on atopic dermatitis (AD) in the BALB/c mouse model. The AdMSCs attenuated clinical symptoms associated with AD, decreased numbers of degranulated mast cells (MCs), IgE level, amount of histamine released, and prostaglandin E2 level. Atopic dermatitis increased the expression levels of cytokines/chemokines, such as interleukin-5 (IL-5), macrophage inflammatory protein-1ß (MIP-1ß), MIP-2, chemokine (C-C motif) ligand 5 (CCL5), and IL-17, in BALB/c mouse. The AdMSCs showed decreased expression levels of these cytokines in the mouse model of AD. In vivo downregulation of MIP-2 attenuated the clinical symptoms associated with AD. Atopic dermatitis increased the expression levels of hallmarks of allergic inflammation, induced interactions of Fc𝜀RIβ with histone deacetylase 3 (HDAC3) and Lyn, increased ß-hexosaminidase activity, increased serum IgE level, and increased the amount of histamine released in an MIP-2-dependent manner. Downregulation of MIP-2 increased the levels of several miRNAs, including miR-122a-5p. Mouse miR-122a-5p mimic inhibited AD, while suppressor of cytokine signaling 1 (SOCS1), a predicted downstream target of miR-122a-5p, was required for AD. The downregulation of SOCS1 decreased the expression levels of MIP-2 and chemokine (C-X-C motif) ligand 13 (CXCL13) in the mouse model of AD. The downregulation of CXCL13 attenuated AD and allergic inflammation such as passive cutaneous anaphylaxis. The role of T cell transcription factors in AD was also investigated. Atopic dermatitis increased the expression levels of T-bet and GATA-3 [transcription factors of T-helper 1 (Th1) and T-helper 2 (Th2) cells, respectively] but decreased the expression of Foxp3, a transcription factor of regulatory T (Treg) cells, in an SOCS1-dependent manner. In addition to this, miR-122a-5p mimic also prevented AD from regulating the expression of T-bet, GATA-3, and Foxp3. Atopic dermatitis increased the expression of cluster of differentiation 163 (CD163), a marker of M2 macrophages, but decreased the expression of inducible nitric oxide synthase (iNOS), a marker of M1 macrophages. Additionally, SOCS1 and miR-122a-5p mimic regulated the expression of CD163 and iNOS in the mouse model of AD. Experiments employing conditioned medium showed interactions between MCs and macrophages in AD. The conditioned medium of AdMSCs, but not the conditioned medium of human dermal fibroblasts, negatively inhibited the features of allergic inflammation. In summary, we investigated the anti-atopic effects of AdMSCs, identified targets of AdMSCs, and determined the underlying mechanism for the anti-atopic effects of AdMSCs.

NLRP3 inflammasome: A likely target for the treatment of allergic diseases

Allergic diseases, such as asthma, rhinitis, dermatitis, conjunctivitis, and anaphylaxis, have recently become a global public health concern. According to previous studies, the NLRP3 inflammasome is a multi-protein complex known to be associated with many inflammatory conditions. In response to allergens or allergen/damage-associated molecular signals, NLRP3 changes its conformation to allow the assembly of the NLRP3 inflammasome complex and activates caspase-1, which is an evolutionarily conserved enzyme that proteolytically cleaves other proteins, such as the precursors of the inflammatory cytokines IL-1β and IL-18. Subsequently, active caspase-1 cleaves pro-IL-1 and pro-IL-18. Recently, accumulating human and mouse experimental evidence has demonstrated that the NLRP3 inflammasome, IL-1β, and IL-18 are critically involved in the development of allergic diseases. Furthermore, the application of specific NLRP3 inflammasome inhibitors has been demonstrated in animal models. Therefore, these inhibitors may represent potential therapeutic methods for the management of clinical allergic disorders. This review summarizes findings related to the NLRP3 inflammasome and its related factors and concludes that specific NLRP3 inflammasome inhibitors may be potential therapeutic agents for allergic diseases.

Properdin: A multifaceted molecule involved in inflammation and diseases

Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases. Properdin is a glycoprotein found in plasma that is mainly produced by leukocytes and can positively regulate AP activity by stabilizing C3 and C5 convertases and initiating the AP. Promotion of complement activity by properdin results in changes in the cellular microenvironment that contribute to innate and adaptive immune responses, including pro-inflammatory cytokine production, immune cell infiltration, antigen presenting cell maturation, and tissue damage. The use of properdin-deficient mouse models and neutralizing antibodies has contributed to the understanding of the mechanisms by which properdin contributes to promoting or preventing disease pathology. This review mainly focusses on the multifaceted roles of properdin in inflammation and diseases, and how understanding these roles is contributing to the development of new disease therapies.

A novel role for neutrophils in IgE-mediated allergy: Evidence for antigen presentation in late-phase reactions

BACKGROUND

Neutrophils and allergen-specific T cells accumulate in patients with allergic late-phase reactions (LPRs). Their presence is associated with severe inflammation. Cytokines, such as GM-CSF, IFN-γ, and IL-3, which are typically found in patients with allergic LPRs, have been proposed to convert neutrophils into antigen-presenting cells (APCs).

OBJECTIVE

We sought to assess the antigen-processing and antigen-presenting capacities of neutrophils from allergic patients.

METHODS

Neutrophils were isolated from peripheral blood of donors with birch pollen allergy and stimulated with GM-CSF, IFN-γ, and IL-3. The viability and expression of HLA-DR, CD80, and CD86 were assessed by using flow cytometry. HLA-DM expression was analyzed by means of immunoblotting. Allergen uptake was studied after fluorescence labeling of the major birch pollen allergen Bet v 1. Bet v 1 was digested with neutrophilic endolysosomal extracts, and the resulting fragments were sequenced by using mass spectrometry. Neutrophils were used as APCs in coculture experiments with autologous HLA-DR-restricted and Bet v 1-specific T-cell clones reactive with epitopes in different regions of the allergen. In all experiments monocytes were used for comparison. Fluids from suction blisters formed on top of LPRs induced by using intradermal allergen injection were assessed for HLA-DR⁺ neutrophils by using flow cytometry.

RESULTS

The cytokines significantly enhanced the survival, allergen uptake, and expression of HLA-DM and HLA-DR on neutrophils. Neutrophils rapidly degraded Bet v 1 into fragments containing all relevant T-cell epitopes. Cytokine-activated, allergen-pulsed neutrophils induced proliferative and cytokine responses of Bet v 1-specific T cells irrespective of epitope specificity, confirming that they fully processed and presented the allergen. HLA-DR⁺ neutrophils were detected in patients with cutaneous allergic LPRs.

CONCLUSION

Neutrophils can serve as APCs for local allergen-specific effector T cells in patients with allergic LPRs.

Molecular Aspects of Allergens and Allergy

Immunoglobulin E (IgE)-associated allergy is the most common immune disorder. More than 30% of the population suffer from symptoms of allergy which are often severe, disabling, and life threatening such as asthma and anaphylaxis. Population-based birth cohort studies show that up to 60% of the world population exhibit IgE sensitization to allergens, of which most are protein antigens. Thirty years ago the first allergen-encoding cDNAs have been isolated. In the meantime, the structures of most of the allergens relevant for disease in humans have been solved. Here we provide an update regarding what has been learned through the use of defined allergen molecules (i.e., molecular allergology) and about mechanisms of allergic disease in humans. We focus on new insights gained regarding the process of sensitization to allergens, allergen-specific secondary immune responses, and mechanisms underlying allergic inflammation and discuss open questions. We then show how molecular forms of diagnosis and specific immunotherapy are currently revolutionizing diagnosis and treatment of allergic patients and how allergen-specific approaches may be used for the preventive eradication of allergy.

Absorption of Nasal and Bronchial Fluids: Precision Sampling of the Human Respiratory Mucosa and Laboratory Processing of Samples

The methods of nasal absorption (NA) and bronchial absorption (BA) use synthetic absorptive matrices (SAM) to absorb the mucosal lining fluid (MLF) of the human respiratory tract. NA is a non-invasive technique which absorbs fluid from the inferior turbinate, and causes minimal discomfort. NA has yielded reproducible results with the ability to frequently repeat sampling of the upper airway.

By comparison, alternative methods of sampling the respiratory mucosa, such as nasopharyngeal aspiration (NPA) and conventional swabbing, are more invasive and may result in greater data variability. Other methods have limitations, for instance, biopsies and bronchial procedures are invasive, sputum contains many dead and dying cells and requires liquefaction, exhaled breath condensate (EBC) contains water and saliva, and lavage samples are dilute and variable.

BA can be performed through the working channel of a bronchoscope in clinic. Sampling is well tolerated and can be conducted at multiple sites in the airway. BA results in MLF samples being less dilute than bronchoalveolar lavage (BAL) samples.

This article demonstrates the techniques of NA and BA, as well as the laboratory processing of the resulting samples, which can be tailored to the desired downstream biomarker being measured. These absorption techniques are useful alternatives to the conventional sampling techniques used in clinical respiratory research.

Lung Diseases

Inflammasomes are large innate cytoplasmic complexes that play a major role in promoting inflammation in the lung in response to a range of environmental and infectious stimuli. Inflammasomes are critical for driving acute innate immune responses that resolve infection and maintain tissue homeostasis. However, dysregulated or excessive inflammasome activation can be detrimental. Here, we discuss the plethora of recent data from clinical studies and small animal disease models that implicate excessive inflammasome responses in the pathogenesis of a number of acute and chronic respiratory inflammatory diseases. Understanding of the role of inflammasomes in lung disease is of great therapeutic interest.

Specificity and reproducibility of nasal biomarkers in patients with allergic rhinitis after allergen challenge chamber exposure

BACKGROUND

Allergic rhinitis is an inflammatory disease that causes cellular influx and mediator release in the nose. These inflammatory changes might be used as nasal biomarkers to assess the efficacy of novel anti-allergic treatments.

OBJECTIVE

To assess the specificity and reproducibility of nasal biomarkers in patients with allergic rhinitis after grass pollen exposure in an allergen challenge chamber.

METHODS

In a monocenter pilot study, 15 patients with allergic rhinitis and 19 healthy individuals underwent two 4-hour Dactylis glomerate pollen challenges in the challenge chamber with an interval of 21 days. Before challenge, on exit, and after 2 and 22 hours, a nasal lavage was performed and nasal secretions were collected on filter paper to determine a wide panel of cells and mediators. Furthermore, total nasal symptom score, nasal flow, and nasal nitric oxide were measured.

RESULTS

Pollen exposure significantly increased eosinophil, interleukin (IL) 5, IL-6, IL-13, and macrophage inflammatory protein 1β levels in allergic patients but not in healthy individuals. The effect could be reproduced for eosinophils, IL-5, IL-6, and macrophage inflammatory protein 1β after the second allergen challenge. By contrast, the IL-13 levels were higher and eotaxin levels first increased after repetitive allergen challenge. There was no correlation between total nasal symptom score and elevated cell or cytokine levels. Nasal nitric oxide levels were nonspecifically elevated in both patients with allergy and healthy controls.

CONCLUSION

A subset of cellular and soluble biomarkers in nasal lavage and secretion reveals specificity and reproducibility in patients with allergic rhinitis. These can be used to measure the immunologic efficacy of antiallergic treatments in an allergen challenge chamber. Carryover effects attributable to priming must be considered when designing cross-over studies.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00297843.

Nasosorption as a Minimally Invasive Sampling Procedure: Mucosal Viral Load and Inflammation in Primary RSV Bronchiolitis

Background

Existing respiratory mucosal sampling methods are flawed, particularly in a pediatric bronchiolitis setting.

Methods

Twenty-four infants with bronchiolitis were recruited: 12 were respiratory syncytial virus (RSV)-positive, 12 were RSV-negative. Infants were sampled by nasosorption and nasopharyngeal aspiration (NPA).

Results

Nasosorption was well tolerated and identified all RSV+ samples. RSV load measured by nasosorption (but not NPA) correlated with length of hospital stay (P = .04) and requirement for mechanical ventilation (P = .03). Nasosorption (but not NPA) levels of interferon γ, interleukin 1β, CCL5/RANTES, and interleukin 10 (IL-10) were elevated in RSV+ bronchiolitis (all P < .05), furthermore CCL5 and IL-10 correlated with RSV load (P < .05).

Conclusions

Nasosorption allowed measurement of RSV load and the mucosal inflammatory response in infants.

Mucosal Type 2 Innate Lymphoid Cells Are a Key Component of the Allergic Response to Aeroallergens

RATIONALE

Newly characterized type 2 innate lymphoid cells (ILC2s) display potent type 2 effector functionality; however, their contribution to allergic airways inflammation and asthma is poorly understood. Mucosal biopsy used to characterize the airway mucosa is invasive, poorly tolerated, and does not allow for sequential sampling.

OBJECTIVES

To assess the role of ILC2s during nasal allergen challenge in subjects with allergic rhinitis using novel noninvasive methodology.

METHODS

We used a human experimental allergen challenge model, with flow cytometric analysis of nasal curettage samples, to assess the recruitment of ILC2s and granulocytes to the upper airways of subjects with atopy and healthy subjects after allergen provocation. Soluble mediators in the nasal lining fluid were measured using nasosorption.

MEASUREMENTS AND MAIN RESULTS

After an allergen challenge, subjects with atopy displayed rapid induction of upper airway symptoms, an enrichment of ILC2s, eosinophils, and neutrophils, along with increased production of IL-5, prostaglandin D2, and eosinophil and T-helper type 2 cell chemokines compared with healthy subjects. The most pronounced ILC2 recruitment was observed in subjects with elevated serum IgE and airway eosinophilia.

CONCLUSIONS

The rapid recruitment of ILC2s to the upper airways of allergic patients with rhinitis, and their association with key type 2 mediators, highlights their likely important role in the early allergic response to aeroallergens in the airways. The novel methodology described herein enables the analysis of rare cell populations from noninvasive serial tissue sampling.

Pathway discovery using transcriptomic profiles in adult-onset severe asthma

BACKGROUND

Adult-onset severe asthma is characterized by highly symptomatic disease despite high-intensity asthma treatments. Understanding of the underlying pathways of this heterogeneous disease is needed for the development of targeted treatments. Gene set variation analysis is a statistical technique used to identify gene profiles in heterogeneous samples.

OBJECTIVE

We sought to identify gene profiles associated with adult-onset severe asthma.

METHODS

This was a cross-sectional, observational study in which adult patients with adult-onset of asthma (defined as starting at age ≥18 years) as compared with childhood-onset severe asthma (<18 years) were selected from the U-BIOPRED cohort. Gene expression was assessed on the total RNA of induced sputum (n = 83), nasal brushings (n = 41), and endobronchial brushings (n = 65) and biopsies (n = 47) (Affymetrix HT HG-U133+ PM). Gene set variation analysis was used to identify differentially enriched predefined gene signatures of leukocyte lineage, inflammatory and induced lung injury pathways.

RESULTS

Significant differentially enriched gene signatures in patients with adult-onset as compared with childhood-onset severe asthma were identified in nasal brushings (5 signatures), sputum (3 signatures), and endobronchial brushings (6 signatures). Signatures associated with eosinophilic airway inflammation, mast cells, and group 3 innate lymphoid cells were more enriched in adult-onset severe asthma, whereas signatures associated with induced lung injury were less enriched in adult-onset severe asthma.

CONCLUSIONS

Adult-onset severe asthma is characterized by inflammatory pathways involving eosinophils, mast cells, and group 3 innate lymphoid cells. These pathways could represent useful targets for the treatment of adult-onset severe asthma.

Sublingual house dust mite immunotherapy has no impact on decrease of circulating erythrocytes upon airway allergen challenge in allergic rhinitis

House dust mite (HDM) allergy is a predominant cause for perennial allergic rhinitis (AR) in Europe. We recently reported that circulating erythrocyte numbers decrease after airway allergen challenge in a murine asthma model and in grass-pollen sensitized AR subjects. Consequently, we aimed to evaluate these findings in HDM sensitized AR subjects and the influence of preceding allergen immunotherapy. Seventy-seven (age 26.8 ± 7.3 years; 54.5% female) HDM-allergic rhinitis subjects previously enrolled in a randomized, monocentric sublingual immunotherapy (SLIT) trial at the Vienna Challenge Chamber (VCC) were included. Subjects had either received placebo (n = 22), low-dose HDM (n = 29) or high-dose HDM specific sublingual immunotherapy (n = 26) daily for 24 weeks. Blood sampling was performed before and after 6 hours of HDM allergen exposure. Overall, specific airway allergen challenge resulted in a significant decrease in circulating erythrocytes and hematocrit (p < 0.001), and elevation of leukocytes (p < 0.001), particularly segmented neutrophils (p < 0.001). Gender had no significant effect on the observed changes in circulating blood cells. Erythrocytes decreased and neutrophil counts increased significantly after airway allergen challenge regardless of preceding immunotherapy. These findings imply a rapid systemic mobilization of neutrophils occurring within immediate type hypersensitivity response upon a specific allergen challenge, which is possibly inversely linked with the erythrocyte numbers.

Relación de los mecanismos inmunológicos del asma y la contaminación ambiental

Introducción. Se calcula que más de 300 millones de personas alrededor del mundo padecen asma y se estima que para el año 2025 esta cifra se incremente a 400 millones debido a los contaminantes criterio. Sin embargo, dadas sus limitaciones, los estudios epidemiológicos son controversiales sobre la contaminación y el desarrollo de asma.Objetivos. Describir las diferencias y similitudes de la respuesta inmunológica de pacientes asmáticos y los modelos animales de asma alérgica después de la exposición a contaminantes criterio y elementos biológicos, para así identificar los factores inmunológicos relacionados con el desarrollo de asma.Materiales y método. Se realizó una búsqueda sistemática en las bases de datos sobre asma y los diferentes contaminantes criterio.Resultados. La respuesta Th2 es activada por la inhalación de ozono, dióxido de nitrógeno, azufre y la exposición aguda a material particulado, mientras que el contacto con ciertos tipos de pólenes y glucanos y la exposición crónica de partículas incrementa la respuesta Th1, la cual inhibe a la respuesta Th2 produciendo un “efecto protector”.Conclusiones. La respuesta Th1 podría causar baja o nula asociación entre la exposición a contaminación y el desarrollo de asma en las diferentes ciudades, adicionando de esta manera otra limitación a los estudios epidemiológicos.

A Comprehensive Evaluation of Nasal and Bronchial Cytokines and Chemokines Following Experimental Rhinovirus Infection in Allergic Asthma: Increased Interferons (IFN-γ and IFN-λ) and Type 2 Inflammation (IL-5 and IL-13)

Background

Rhinovirus infection is a major cause of asthma exacerbations.

Objectives

We studied nasal and bronchial mucosal inflammatory responses during experimental rhinovirus-induced asthma exacerbations.

Methods

We used nasosorption on days 0, 2–5 and 7 and bronchosorption at baseline and day 4 to sample mucosal lining fluid to investigate airway mucosal responses to rhinovirus infection in patients with allergic asthma (n = 28) and healthy non-atopic controls (n = 11), by using a synthetic absorptive matrix and measuring levels of 34 cytokines and chemokines using a sensitive multiplex assay.

Results

Following rhinovirus infection asthmatics developed more upper and lower respiratory symptoms and lower peak expiratory flows compared to controls (all P < 0.05). Asthmatics also developed higher nasal lining fluid levels of an anti-viral pathway (including IFN-γ, IFN-λ/IL-29, CXCL11/ITAC, CXCL10/IP10 and IL-15) and a type 2 inflammatory pathway (IL-4, IL-5, IL-13, CCL17/TARC, CCL11/eotaxin, CCL26/eotaxin-3) (area under curve day 0–7, all P < 0.05). Nasal IL-5 and IL-13 were higher in asthmatics at day 0 (P < 0.01) and levels increased by days 3 and 4 (P < 0.01). A hierarchical correlation matrix of 24 nasal lining fluid cytokine and chemokine levels over 7 days demonstrated expression of distinct interferon-related and type 2 pathways in asthmatics. In asthmatics IFN-γ, CXCL10/IP10, CXCL11/ITAC, IL-15 and IL-5 increased in bronchial lining fluid following viral infection (all P < 0.05).

Conclusions

Precision sampling of mucosal lining fluid identifies robust interferon and type 2 responses in the upper and lower airways of asthmatics during an asthma exacerbation. Nasosorption and bronchosorption have potential to define asthma endotypes in stable disease and at exacerbation.

•

Following rhinovirus infection asthmatics have increased interferons and type 2 inflammation in airway mucosal lining fluid.

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Nasosorption cytokines and chemokines showed distinct pathways of interferon and type 2 inflammation in asthma.

•

Precision mucosal sampling has potential for stratifying molecular endotypes of asthma.

•

Validation of nasosorption and bronchosorption will be required for selection of asthmatics for therapy with biologics.

Experimental human rhinovirus (HRV) infection causes more severe upper and lower respiratory tract symptoms in allergic asthmatics than in healthy controls. There is greater induction of cytokines and chemokines in nasal and bronchial mucosal lining fluid (MLF) of asthmatics: with distinct pathways of type 2 and anti-viral/regulatory inflammation.

Subject to further validation, analysis of MLF may prove useful in stratification of patients with asthma, and the definition of molecular endotypes.

Interpretation

Nasosorption and bronchosorption are precision sampling methods with potential for widespread application in respiratory and other mucosal diseases (e.g. gastrointestinal diseases).

Biomarkers identified in nasosorption and bronchosorption samples will need to be validated compared to established airway sampling methods, in a range of asthma phenotypes, and with current and novel therapies.

Novel Analysis of Immune Cells from Nasal Microbiopsy Demonstrates Reliable, Reproducible Data for Immune Populations, and Superior Cytokine Detection Compared to Nasal Wash

The morbidity and mortality related to respiratory tract diseases is enormous, with hundreds of millions of individuals afflicted and four million people dying each year. Understanding the immunological processes in the mucosa that govern outcome following pathogenic encounter could lead to novel therapies. There is a need to study responses at mucosal surfaces in humans for two reasons: (i) Immunological findings in mice, or other animals, often fail to translate to humans. (ii) Compartmentalization of the immune system dictates a need to study sites where pathogens reside. In this manuscript, we describe two novel non-invasive nasal mucosal microsampling techniques and their use for measuring immunological parameters: 1) using nasal curettes to collect cells from the inferior turbinate and; 2) absorptive matrices to collect nasal lining fluid. Both techniques were well tolerated and yielded reproducible and robust data. We demonstrated differences in immune populations and activation state in nasal mucosa compared to blood as well as compared to nasopharyngeal lumen in healthy adults. We also found superior cytokine detection with absorptive matrices compared to nasal wash. These techniques are promising new tools that will facilitate studies of the immunological signatures underlying susceptibility and resistance to respiratory infections.