Type 2-polarized memory B cells hold allergen-specific IgE memory.

Allergen-specific immunoglobulin E (IgE) antibodies mediate pathology in diseases such as allergic rhinitis and food allergy. Memory B cells (MBCs) contribute to circulating IgE by regenerating IgE-producing plasma cells upon allergen encounter. Here, we report a population of type 2-polarized MBCs defined as CD23hi, IL-4Rαhi, and CD32low at both the transcriptional and surface protein levels. These MBC2s are enriched in IgG1- and IgG4-expressing cells while constitutively expressing germline transcripts for IgE. Allergen-specific B cells from patients with allergic rhinitis and food allergy were enriched in MBC2s. Furthermore, MBC2s generated allergen-specific IgE during sublingual immunotherapy, thereby identifying these cells as a major reservoir for IgE. The identification of MBC2s provides insights into the maintenance of IgE memory, which is detrimental in allergic diseases but could be beneficial in protection against venoms and helminths.

Oligomerization and Nitration of the Grass Pollen Allergen Phl p 5 by Ozone, Nitrogen Dioxide, and Peroxynitrite: Reaction Products, Kinetics, and Health Effects.

The allergenic and inflammatory potential of proteins can be enhanced by chemical modification upon exposure to atmospheric or physiological oxidants. The molecular mechanisms and kinetics of such modifications, however, have not yet been fully resolved. We investigated the oligomerization and nitration of the grass pollen allergen Phl p 5 by ozone (O3), nitrogen dioxide (NO2), and peroxynitrite (ONOO-). Within several hours of exposure to atmospherically relevant concentration levels of O3 and NO2, up to 50% of Phl p 5 were converted into protein oligomers, likely by formation of dityrosine cross-links. Assuming that tyrosine residues are the preferential site of nitration, up to 10% of the 12 tyrosine residues per protein monomer were nitrated. For the reaction with peroxynitrite, the largest oligomer mass fractions (up to 50%) were found for equimolar concentrations of peroxynitrite over tyrosine residues. With excess peroxynitrite, the nitration degrees increased up to 40% whereas the oligomer mass fractions decreased to 20%. Our results suggest that protein oligomerization and nitration are competing processes, which is consistent with a two-step mechanism involving a reactive oxygen intermediate (ROI), as observed for other proteins. The modified proteins can promote pro-inflammatory cellular signaling that may contribute to chronic inflammation and allergies in response to air pollution.

What is the contribution of IgE to nasal polyposis?

Taking a novel approach, this narrative review collates knowledge about nasal polyposis and the biological functions of IgE in several diseases (allergic rhinitis, allergic asthma, nonsteroidal anti-inflammatory drugs-exacerbated respiratory disease, and chronic spontaneous urticaria) to consider which IgE-mediated mechanisms are relevant to nasal polyposis pathology. A type 2 eosinophil-dominated inflammatory signature is typical in nasal polyp tissue of European patients with nasal polyposis, with a shift toward this endotype observed in Asian populations in recent years. Elevated polyclonal IgE is present in the nasal tissue of patients with and without allergy. It is derived from many different B-cell clones and, importantly, is functional (proinflammatory). Staphylococcus aureus enterotoxins are thought to act as superantigens, inducing production of polyclonal IgE via B-cell and T-cell activation, and triggering release of inflammatory mediators. In some patients, exposure to antigens/triggers leads to production of high levels of antigen-specific IgE, which mediates cross-linking of the high-affinity IgE receptor on various cells, causing release of inflammatory mediators. The efficacy of omalizumab confirms IgE as an important inflammatory mediator in nasal polyposis. By blocking IgE, omalizumab targets the T2 inflammation in nasal polyposis, reduces nasal polyp score and improves symptoms.

Eicosanoids seasonally impact pulmonary function in asthmatic patients with Japanese cedar pollinosis.

BACKGROUND: Condition of asthma in patients with asthma and concomitant seasonal allergic rhinitis (SAR) deteriorates during the Japanese cedar pollen (JCP) season. However, the underlying mechanisms remain unclear. METHODS: We analyzed seasonal variations in eicosanoid levels in the airways of patients with asthma and concomitant SAR sensitized to JCP (N = 29, BA-SAR-JCP group) and those not sensitized (N = 13, BA-AR-non-JCP group) during the JCP season. The association between changes in eicosanoid concentrations and pulmonary function was assessed. Exhaled breath condensate (EBC) was collected, and pulmonary function tests were performed during the JCP and non-JCP seasons. The cysteinyl leukotriene (CysLT), thromboxane B2 (TXB2), prostaglandin D2-methoxime (PGD2-MOX), and leukotriene B4 (LTB4) levels in the collected EBC were measured via enzyme-linked immunosorbent immunoassays. RESULTS: The log CysLT levels significantly increased in the BA-SAR-JCP group during the JCP season compared with the non-JCP season (1.78 ± 0.55, 1.39 ± 0.63 pg/mL, mean ± standard deviation, respectively, p = 0.01) and those in the BA-AR-non-JCP group during the JCP season (1.39 ± 0.38 pg/mL, p = 0.04). Moreover, the log TXB2 levels seemed to increase. However, the log LTB4 and log PGD2-MOX levels did not increase. The changes in the log CysLT levels during the two seasons were negatively correlated to forced expiratory volume in one second (FEV1) in the BA-SAR-JCP group (r = -0.52, p < 0.01). CONCLUSIONS: In the BA-SAR-JCP group, seasonal increases in eicosanoid levels in the airway likely promoted deterioration in pulmonary function despite optimal maintenance treatment.

Dramatically decreased T cell responses but persistent IgE upon reduced pollen exposure.

Mugwort pollen allergy is frequent in parts of Europe. As mugwort pollen contains only one major allergen, Art v 1, which harbors only one T cell epitope, we employed mugwort pollen allergy as a model to study allergen-specific T cell responses. However, after 2004, we noticed a drastic decrease in the T cell responses to Art v 1 and eventually it became almost impossible to detect allergen-specific responses at the T cell level in mugwort-allergic individuals. To explain this observation, we retrospectively investigated the local exposure to mugwort pollen and its possible correlation to the frequency and reactivity of allergen-specific T cells. The total annual pollen indices dramatically dropped after 2004 and never reached previous levels again. Local sensitization to mugwort pollen and serum IgE antibodies specific for Art v 1 remained unchanged until 2015. Our mugwort pollen model shows that specific IgE-levels are maintained for extremely long time periods in spite of a long-term reduction of natural allergen exposure to levels that are too low to boost specific T cells.

Lactobacillus helveticus SBT2171 alleviates allergic symptoms in a murine model for pollen allergy.

Lactic acid bacteria are known to have various health-promoting effects and are highly expected to find applications in anti-allergic food materials. In this study, we focused on Lactobacillus helveticus SBT2171 (LH2171), which reportedly modifies some unique immune responses and ameliorated symptoms of patients allergic to mites and house dust in the previous studies. We examined the effect of LH2171 on cytokine production by antigen-stimulated murine naïve splenocytes in vitro and demonstrated that it inhibited IL-4 and IL-13 production while enhancing IFN-γ and IL-10 production. Then, we examined the anti-allergic effect of LH2171 in vivo using a murine model of pollen allergy and found that LH2171 reduced the sneezing frequency when orally administered to mice. We successfully confirmed the immune modulatory activity of LH2171 and its anti-allergic activity against inhaled antigens. These evidences would contribute to identifying the anti-allergic mechanism of LH2171.Abbreviations: ALDH: aldehyde dehydrogenase; EGCG: epigallocatechin gallate; LAB: lactic acid bacteria; LH2171: Lactobacillus helveticus SBT2171; NALT: nasal-associated lymphoid tissue; OVA: ovalbumin.

Birch pollen-specific subcutaneous immunotherapy reduces ILC2 frequency but does not suppress IL-33 in mice.

BACKGROUND: The underlying mechanism of allergen-specific subcutaneous immunotherapy (SCIT) is not yet fully understood, but suppression of allergen-specific Th2 cells and production of allergen-specific IgG4 antibodies are two hallmarks. The impact on the innate arm of the immune system is far less clear. OBJECTIVE: The aim of this study was to investigate the effect of birch pollen (BP) SCIT on the innate immune response in a BP SCIT mouse model. METHODS: Mice with birch pollen-induced allergic airway inflammation received weekly subcutaneous immunotherapy injections with birch pollen extract (BPE) adsorbed to alum. The effect of the BP SCIT on innate cytokine levels in lung, the number and the functionality of ILC2s and the airway inflammation was determined. RESULTS: Mice with BP allergy had an increased level of the innate cytokines IL-33, IL-25, GM-CSF and IL-5+ ILC2s in the lungs. BP SCIT suppressed the number of IL-5+ ILC2s, mast cell tryptase release, Th2 cytokine production, eosinophil recruitment and peribronchial inflammatory infiltrates. In contrast, innate cytokine production and collagen deposition in the airways were not affected. CONCLUSION AND CLINICAL RELEVANCE: BP SCIT is able to suppress the adaptive and part of the innate immune response, but this is not sufficient to inhibit collagen deposition and the IL-33 expression in the airways in mice.

Glucocorticoid-Induced Transcription Factor 1 (GLCCI1) Variant Impacts the Short-Term Response to Intranasal Corticosteroids in Chinese Han Patients with Seasonal Allergic Rhinitis.

BACKGROUND Genetic correlations with the response to intranasal corticosteroids (INCS) in seasonal allergic rhinitis (SAR) treatment are unknown. This study aimed to evaluate the role of gene polymorphisms in the response to INCS in Chinese Han patients with moderate to severe SAR. MATERIAL AND METHODS In this study, 286 Chinese Han patients with SAR were genotyped for 4 candidate genes: the glucocorticosteroid receptor (NR3C1) gene, glucocorticoid-induced transcription factor 1 (GLCCI1) gene, T-box 21 gene (TBX21), and ATP binding cassette subfamily B member 1 (ABCB1) gene. Patients were treated with INCS for 4 weeks. The total nasal symptom score (TNSS), total ocular symptom score (TOSS), and visual analogue scale (VAS) score were assessed at baseline and on week 4. The primary endpoint was the effective rate after 4 weeks of INCS therapy. RESULTS In addition to the known contributing factors, one genotype of GLCCI1, namely, rs37973, was significantly associated with the INCS response (OR=0.598, 95% confidence interval: 0.41 to 0.87, P=0.007). The effective rate of the GG group was lower than those of the AA and AG groups (AA vs. GG: 73.7% vs. 51.6%, P=0.007; AG vs. GG: 78.8% vs. 51.6%, P=0.000). In addition, the TNSS, TOSS, and VAS were higher for the patients in the GG group than for those in the AA and AG groups on week 4. CONCLUSIONS The GLCCI1 rs37973 variant is a risk factor for glucocorticoid resistance in Chinese patients with SAR who receive short-term INCS treatment.

Blood and nasal epigenetics correlate with allergic rhinitis symptom development in the environmental exposure unit.

BACKGROUND: Epigenetic alterations may represent new therapeutic targets and/or biomarkers of allergic rhinitis (AR). Our aim was to examine genome-wide epigenetic changes induced by controlled pollen exposure in the environmental exposure unit (EEU). METHODS: 38 AR sufferers and eight nonallergic controls were exposed to grass pollen for 3 hours on two consecutive days. We interrogated DNA methylation at baseline and 3 hours in peripheral blood mononuclear cells (PBMCs) using the Infinium Methylation 450K array. We corrected for demographics, cell composition, and multiple testing (Benjamini-Hochberg) and verified hits using bisulfite PCR pyrosequencing and qPCR. To extend these findings to a clinically relevant tissue, we investigated DNA methylation and gene expression of mucin 4 (MUC4), in nasal brushings from a separate validation cohort exposed to birch pollen. RESULTS: In PBMCs of allergic rhinitis participants, 42 sites showed significant DNA methylation changes of 2% or greater. DNA methylation changes in tryptase gamma 1 (TPSG1), schlafen 12 (SLFN12), and MUC4 in response to exposure were validated by pyrosequencing. SLFN12 DNA methylation significantly correlated with symptoms (P < 0.05), and baseline DNA methylation pattern was found to be predictive of symptom severity upon grass allergen exposure (P = 0.029). Changes in MUC4 DNA methylation in nasal brushings in the validation cohort correlated with drop in peak nasal inspiratory flow (Spearman's r = 0.314, P = 0.034), and MUC4 gene expression was significantly increased (P < 0.0001). CONCLUSION: This study revealed novel and rapid epigenetic changes upon exposure in a controlled allergen challenge facility, and identified baseline epigenetic status as a predictor of symptom severity.

Exhaled nitric oxide atopy, and spirometry in asthma and rhinitis patients in India.

INTRODUCTION: Asthma is a chronic airway inflammatory disorder. Nitric oxide (NO) is non-invasively measured in exhaled breath (FeNO). The aim of the study was to investigate the anthropometric and physiologic factors that influence FeNO measurements. Also, to evaluate FeNO correlation with spirometry and inflammatory markers in asthma and rhinitis. MATERIAL AND METHODS: The study was a prospective analysis of asthma (BA) and rhinitis (AR) in patients enrolled from outpatient clinics between 2011 and 2015. Healthy controls (HC) were enrolled from the community. All subjects underwent baseline spirometry with reversibility, FeNO measurements, skin prick tests, and blood sampling for absolute eosinophil counts and serum total IgE levels. RESULTS: Of 528 enrolled participants, 215 were BA, 248 were BA-AR and 65 were HC. The mean FeNO was higher in atopic versus nonatopic subjects (34.14 vs. 25.99; p < 0.001); asthmatics versus non-asthmatics (30.46 vs. 12.91; p < 0.001), and in participants with BA-AR, compared to those without BA-AR (32.56 vs. 30.46; p < 0.001). The odds ratio for FeNO in the study population showed a significant positive association with male gender, absolute eosinophil count (AEC), breathlessness, duration of symptoms, family history and atopy. In examining the diagnostic accuracy of FeNO for asthma, the AUC for FeNO value is 0.833 (95% confidence interval [CI], 0.717-0.901), with cut-off levels to screen for asthma being 19.45 at 71.2% sensitivity and 81.8% specificity (p < 0.001). The Positive Predictive Value 96.84% (95% CI: 94.43-98.23) and Negative Predictive Value 30% (95% CI: 23.78-37.05) for asthma prediction with FeNO. CONCLUSION: The study highlights the importance of estimation of anthropometric parameters and dyspnea assessment in the evaluation of FeNO levels. Also, the presence of atopy may influence the results in the interpretation of FeNO readings. Moreover, the study have demonstrated that spirometry and FeNO have no significant correlation, which further lays emphasis on them as being different physiological parameters of asthma.  .

Safety and pharmacodynamics of intranasal GSK2245035, a TLR7 agonist for allergic rhinitis: A randomized trial.

BACKGROUND: Toll-like receptor 7 (TLR7) stimulation in the airways may reduce responses to aeroallergens by induction of type 1 interferons (IFNs). GSK2245035 is a novel selective TLR7 agonist in pharmaceutical development. OBJECTIVE: Assessment of safety, pharmacodynamics and nasal allergic reactivity following repeated weekly intranasal (i.n.) GSK2245035. METHODS: This randomized, double-blind, placebo-controlled study (TL7116958) was conducted over two pollen seasons (2013-2014) and follow-up study (204509) conducted 1 year later. Participants with allergic rhinitis (n=42) were randomized to receive eight weekly doses of i.n. GSK2245035 (20 ng [2014 Cohort; n=14] or 80 ng [2013 Cohort; n=14]) or placebo (n=14). Adverse events (AEs) including cytokine release syndrome AEs (CytoRS-AEs) and nasal symptoms were assessed. Nasal and serum IFN-inducible protein 10 (IP-10) were measured after doses 1 and 8, then 1 (follow-up visit [FUV] 1) and 3 (FUV2) weeks after final dose. Nasal allergen challenges (NACs) and allergic biomarker assessment (nasal, serum) were conducted at baseline, FUV1, FUV2 and at a FUV 1 year after final dose (FUV3; 2014 Cohort only). A Bayesian framework enabled probability statements for mean effect sizes. RESULTS: GSK2245035 induced CytoRS-AEs (most commonly headache, median duration <1 day) in 93% of participants at 80 ng, while AE incidence at 20 ng was similar to placebo. There was no evidence of nasal inflammation. Dose-related increases in nasal and serum IP-10 were observed 24 hours after doses 1 and 8 (>95% certainty). Both doses showed a trend in reducing total nasal symptom score 15 minutes post-NAC at FUV1 and FUV2, but there was no reduction evident at FUV3. Nasal levels of selected allergic biomarkers demonstrated trends for reductions at FUV1, FUV2 and FUV3. CONCLUSIONS AND CLINICAL RELEVANCE: Weekly i.n. GSK2245035 20 ng was well tolerated and reduced allergic reactivity to nasal challenge for 3 weeks post-treatment.

The TLR4-TRIF pathway can protect against the development of experimental allergic asthma.

The Toll-like receptor (TLR) adaptor proteins myeloid differentiating factor 88 (MyD88) and Toll, interleukin-1 receptor and resistance protein (TIR) domain-containing adaptor inducing interferon-ß (TRIF) comprise the two principal limbs of the TLR signalling network. We studied the role of these adaptors in the TLR4-dependent inhibition of allergic airway disease and induction of CD4+ ICOS+ T cells by nasal application of Protollin™, a mucosal adjuvant composed of TLR2 and TLR4 agonists. Wild-type (WT), Trif-/- or Myd88-/- mice were sensitized to birch pollen extract (BPEx), then received intranasal Protollin followed by consecutive BPEx challenges. Protollin's protection against allergic airway disease was TRIF-dependent and MyD88-independent. TRIF deficiency diminished the CD4+ ICOS+ T-cell subsets in the lymph nodes draining the nasal mucosa, as well as their recruitment to the lungs. Overall, TRIF deficiency reduced the proportion of cervical lymph node and lung CD4+ ICOS+ Foxp3- cells, in particular. Adoptive transfer of cervical lymph node cells supported a role for Protollin-induced CD4+ ICOS+ cells in the TRIF-dependent inhibition of airway hyper-responsiveness. Hence, our data demonstrate that stimulation of the TLR4-TRIF pathway can protect against the development of allergic airway disease and that a TRIF-dependent adjuvant effect on CD4+ ICOS+ T-cell responses may be a contributing mechanism.

"Allergic mood" - Depressive and anxiety symptoms in patients with seasonal allergic rhinitis (SAR) and their association to inflammatory, endocrine, and allergic markers.

A growing number of studies show an association between seasonal allergic rhinitis (SAR) with depression and anxiety. The underlying mechanisms of a link between SAR and affect, however, are still unclear. The objective of the present study was to investigate depressive symptoms and anxiety in SAR patients and their association to inflammatory and endocrine parameters. SAR patients (n=41) and non-allergic, healthy controls (n=42) were assessed during (pollen season) and out of symptomatic periods (non-pollen season). Inflammatory cytokine profile (Interleukin [IL]-2, IL-4, IL-6, IL-8, IL-10, IL-17, IFN-γ, TNF-α), Immunoglobulin-E (IgE), hair cortisol concentrations (HCC), as well as sleep quality were measured. The present data show that during acute allergic inflammation SAR patients experienced a significant increase in Beck Depression Inventory (BDI-) II scores when (a) compared to the asymptomatic period and (b) when compared to the non-allergic controls, while no differences in anxiety were observed. Increased BDI-II scores in SAR patients were significantly associated with levels of IL-6 as well as IL-6/IL-10 and IFN-γ/IL-10 ratios and further, to an early age at manifestation of SAR and poor sleep quality. These findings support a close relationship between acute allergic processes and affective states, with inflammatory cytokines, sleep, and age of manifestation as potentially relevant mediators.

Does seasonal allergic rhinitis increase sensitivity to ammonia exposure?

Allergic inflammation in the upper airways represents a wide-spread health issue: Little is known about whether it increases sensitivity to airborne chemicals thereby challenging established exposure limits that neglect such differences in susceptibility. To investigate the role of pre-existing allergic inflammation, 19 subjects with seasonal allergic rhinitis (SAR) and 18 control subjects with low risk of sensitization were exposed for 4h to ammonia in two concentrations (cross-over design): 2.5ppm (odor threshold) and 0-40ppm (occupational exposure limit: 20ppm TWA). Prior to the whole-body exposure, it was confirmed that subjects with SAR showed persistent inflammation outside the pollen season as indicated by increased exhaled nitric oxide and total immunoglobulin E in serum compared to controls. Despite concentration-dependent increases in chemosensory perceptions and acute symptoms, SAR status did not modulate subjective effects of exposure. Moreover, SAR status did not affect the investigated physiological endpoints of sensory irritation: While eye-blink recordings confirmed weak ocular irritation properties of ammonia at 0-40ppm, this effect was not enhanced in SAR subjects compared to controls. Irrespective of SAR status, exposure to 0-40ppm ammonia did not result in a cortisol stress response, objective nasal obstruction as measured with anterior active rhinomanometry, or an inflammatory response as indexed by substance P, tumor-necrosis-factor α, and high-mobility-group protein 1 in nasal lavage fluid. At least for the malodorous compound ammonia, these results do not support the hypothesis that SAR enhances chemosensory effects in response to local irritants. Before generalizing this finding, more compounds as well as sensitization to perennial allergens need to be investigated.

A randomized controlled phase II clinical trial comparing ONO-4053, a novel DP1 antagonist, with a leukotriene receptor antagonist pranlukast in patients with seasonal allergic rhinitis.

BACKGROUND: Prostaglandin D2 (PGD2 ) is primarily produced by mast cells and is contributing to the nasal symptoms including nasal obstruction and rhinorrhea. OBJECTIVE: This study aimed to evaluate the efficacy and safety of a novel PGD2 receptor 1 (DP1) antagonist, ONO-4053, in patients with seasonal allergic rhinitis (SAR). METHODS: This study was a multicenter, randomized, double-blind, parallel-group study of patients with SAR. Following a one-week period of placebo run-in, patients who met the study criteria were randomized to either the ONO-4053, leukotriene receptor antagonist pranlukast, or placebo group for a two-week treatment period. A total of 200 patients were planned to be randomly assigned to receive ONO-4053, pranlukast, or placebo in a 2:2:1 ratio. Nasal and eye symptoms were evaluated. RESULTS: Both ONO-4053 and pranlukast had higher efficacy than placebo on all nasal and eye symptoms. ONO-4053 outperformed pranlukast in a total of three nasal symptom scores (T3NSS) as well as in individual scores for sneezing, rhinorrhea, and nasal itching. For T3NSS, the Bayesian posterior probabilities that pranlukast was better than placebo and ONO-4053 was better than pranlukast were 70.0% and 81.6%, respectively, suggesting that ONO-4053 has a higher efficacy compared with pranlukast. There was no safety-related issue in this study. CONCLUSIONS: We demonstrated that the efficacy of ONO-4053 was greater than that of pranlukast with a similar safety profile. This study indicates the potential of ONO-4053 for use as a treatment for SAR (JapicCTI-142706).