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.

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.

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.

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.

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.

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.

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.

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.

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).

"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.

Identification of potential crucial gene network related to seasonal allergic rhinitis using microarray data.

The aim of this study was to reveal a potential key gene network associated with seasonal allergic rhinitis (SAR). The microarray data GSE50101 downloaded from Gene Expression Omnibus were used to screen differentially expressed genes (DEGs) between SAR patients and healthy controls. Then, functional enrichment analysis was conducted using Database for Annotation, Visualization, and Integrated Discovery. Afterwards, the protein-protein interactions (PPIs) of DEGs were obtained from STRING, and the PPI network was constructed. In addition, the PPI network module was analyzed. In total, 98 up-regulated and 63 down-regulated DEGs were identified from the SAR samples, comparing the healthy controls. The up-regulated DEGs were mainly enriched in the Gene Ontology terms about cell death (e.g., DUSP1 and JUN) and pathways related to immune (e.g., FOS and JUN). The down-regulated DEGs were mainly enriched in regulation of transcription (e.g., CEBPD and SCML1). In the PPI network, a set of genes was predicted to interact with each other, such as FOS, JUN, and CEBPD. Furthermore, genes in the network module (e.g., FOS, JUN and CEBPD) was mainly enriched in regulation of transcription, and pathways about immune, such as mitogen-activated protein kinase signaling pathway, B cell receptor signaling pathway, and toll-like receptor signaling pathway. Several genes related to immunity and regulation of transcription, such as FOS, JUN, and CEBPD, may play crucial roles during the process of SAR through the interactions with each other.

Novel vaccines targeting dendritic cells by coupling allergoids to nonoxidized mannan enhance allergen uptake and induce functional regulatory T cells through programmed death ligand 1.

BACKGROUND: Allergen immunotherapy (AIT) is the only curative treatment for allergy. AIT faces pitfalls related to efficacy, security, duration, and patient compliance. Novel vaccines overcoming such inconveniences are in demand. OBJECTIVES: We sought to study the immunologic mechanisms of action for novel vaccines targeting dendritic cells (DCs) generated by coupling glutaraldehyde-polymerized grass pollen allergoids to nonoxidized mannan (PM) compared with glutaraldehyde-polymerized allergoids (P) or native grass pollen extracts (N). METHODS: Skin prick tests and basophil activation tests with N, P, or PM were performed in patients with grass pollen allergy. IgE-blocking experiments, flow cytometry, confocal microscopy, cocultures, suppression assays, real-time quantitative PCR, ELISAs, and ELISpot assays were performed to assess allergen capture by human DCs and T-cell responses. BALB/c mice were immunized with PM, N, or P. Antibody levels, cytokine production by splenocytes, and splenic forkhead box P3 (FOXP3)(+) regulatory T (Treg) cells were quantified. Experiments with oxidized PM were also performed. RESULTS: PM displays in vivo hypoallergenicity, induces potent blocking antibodies, and is captured by human DCs much more efficiently than N or P by mechanisms depending on mannose receptor- and dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin-mediated internalization. PM endorses human DCs to generate functional FOXP3(+) Treg cells through programmed death ligand 1. Immunization of mice with PM induces a shift to nonallergic responses and increases the frequency of splenic FOXP3(+) Treg cells. Mild oxidation impairs these effects in human subjects and mice, demonstrating the essential role of preserving the carbohydrate structure of mannan. CONCLUSIONS: Allergoids conjugated to nonoxidized mannan represent suitable vaccines for AIT. Our findings might also be of the utmost relevance to development of therapeutic interventions in other immune tolerance-related diseases.

Changes in markers associated with dendritic cells driving the differentiation of either TH2 cells or regulatory T cells correlate with clinical benefit during allergen immunotherapy.

BACKGROUND: Regulatory dendritic cell (DC) markers, such as C1Q, are upregulated in PBMCs of patients with grass pollen allergy exhibiting clinical benefit during allergen immunotherapy (AIT). OBJECTIVES: We sought to define markers differentially expressed in human monocyte-derived DCs differentiated toward a proallergic (DCs driving the differentiation of TH2 cells [DC2s]) phenotype and investigate whether changes in such markers in the blood correlate with AIT efficacy. METHODS: Transcriptomes and proteomes of monocyte-derived DCs polarized toward DCs driving the differentiation of TH1 cells (DC1s), DC2s, or DCs driving the differentiation of regulatory T cells (DCreg cells) profiles were compared by using genome-wide cDNA microarrays and label-free quantitative proteomics, respectively. Markers differentially regulated in DC2s and DCreg cells were assessed by means of quantitative PCR in PBMCs from 80 patients with grass pollen allergy before and after 2 or 4 months of sublingual AIT in parallel with rhinoconjunctivitis symptom scores. RESULTS: We identified 20 and 26 new genes/proteins overexpressed in DC2s and DCreg cells, respectively. At an individual patient level, DC2-associated markers, such as CD141, GATA3, OX40 ligand, and receptor-interacting serine/threonine-protein kinase 4 (RIPK4), were downregulated after a 4-month sublingual AIT course concomitantly with an upregulation of DCreg cell-associated markers, including complement C1q subcomponent subunit A (C1QA), FcγRIIIA, ferritin light chain (FTL), and solute carrier organic anion transporter family member 2B1 (SLCO2B1), in the blood of clinical responders as opposed to nonresponders. Changes in such markers were better correlated with clinical benefit than alterations of allergen-specific CD4(+) T-cell or IgG responses. CONCLUSIONS: A combination of 5 markers predominantly expressed by blood DCs (ie, C1Q and CD141) or shared with lymphoid cells (ie, FcγRIIIA, GATA3, and RIPK4) reflecting changes in the balance of regulatory/proallergic responses in peripheral blood can be used as early as after 2 months to monitor the early onset of AIT efficacy.

Improved preparation of nasal lavage fluid (NLF) as a noninvasive sample for proteomic biomarker discovery.

UNLABELLED: Nasal lavage fluid (NLF) becomes more and more important as a noninvasive patient sample serving as a new opportunity to discover new biomarkers in diverse human diseases comprising mainly respiratory disorders. This was supported by the observation that the protein profile of NLF differs from conventional samples of i.e. whole blood, hence being capable to complement or even expand the so far biomarker index. Since sample acquisition and processing are the most crucial steps for a profound and sensitive identification we present here a modified protocol of NLF generation and measurement. We show that mild washing steps for sample generation followed by column-mediated concentration and acetone precipitation are appropriate steps to minimize serum leakage by concomitantly highlighting proteins which represent typical components of NLF. This is shown by separation of proteins via 2D-PAGE followed by LC-MS/MS as well as Gel-LC-MS/MS measurements of cut and digested protein spots/bands. SIGNIFICANCE: For a better understanding of the molecular mechanisms underlying respiratory diseases NLF samples are favored sources for protein research. NLF acquisition and sample processing were impaired so far by the problem of blood serum leakage and high salt content. Here, we present a modified protocol of NLF generation leading to the display of typical inventory of NLF proteins combined with reduced salt and serum contaminants. By this, both assay reproducibility and the detection of up- or down-regulated proteins reliably can be discovered in the case of biomarker screenings in a disease versus control design. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.

Pollen derived low molecular compounds enhance the human allergen specific immune response in vivo.

BACKGROUND: Besides allergens, pollen release bioactive, low molecular weight compounds that modulate and stimulate allergic reactions. Clinical relevance of these substances has not been investigated to date. OBJECTIVE: To elucidate the effect of a non-allergenic, low molecular weight factors from aqueous birch pollen extracts (Bet-APE < 3 kDa) on the human allergic immune response in vivo. METHODS: Birch and grass pollen allergic individuals underwent skin prick testing with allergen alone, allergen plus Bet-APE < 3 kDa, or allergen plus pre-identified candidate substances from low molecular pollen fraction. Nasal allergen challenges were performed in non-atopic and pollen allergic individuals using a 3 day repeated threshold challenge battery. Subjects were either exposed to allergen alone or to allergen plus Bet-APE< 3 kDa. Local cytokine levels, nasal secretion weights, nasal congestion and symptom scores were determined. RESULTS: Skin prick test reactions to pollen elicited larger weals when allergens were tested together with the low molecular weight compounds from pollen. Similar results were obtained with candidate pollen-associated lipid mediators. In nasal lining fluids of allergic patients challenged with allergen plus Bet-APE < 3 kDa, IL-8 and IgE was significantly increased as compared to allergen-only challenged patients. These patients also produced increased amounts of total nasal secretion and reported more severe rhinorrhea than the allergen-only challenged group. CONCLUSIONS: Low molecular compounds from pollen enhance the allergen specific immune response in the skin and nose. They are therefore of potential clinical relevance in allergic patients.

Lack of allergy to timothy grass pollen is not a passive phenomenon but associated with the allergen-specific modulation of immune reactivity.

BACKGROUND: Timothy grass (TG) pollen is a common seasonal airborne allergen associated with symptoms ranging from mild rhinitis to severe asthma. OBJECTIVE: The aim of this study was to characterize changes in TG-specific T cell responses as a function of seasonality. METHODS: Peripheral blood mononuclear cells (PBMCs) obtained from allergic individuals and non-allergic controls, either during the pollen season or out of season, were stimulated with either TG extract or a pool of previously identified immunodominant antigenic regions. RESULTS: PBMCs from allergic subjects exhibit higher IL-5 and IL-10 responses in season than when collected out of season. In the case of non-allergic subjects, as expected we observed lower IL-5 responses and robust production of IFN-γ compared to allergic individuals. Strikingly, non-allergic donors exhibited an opposing pattern, with decreased immune reactivity in season. The broad down-regulation in non-allergic donors indicates that healthy individuals are not oblivious to allergen exposure, but rather react with an active modulation of responses following the antigenic stimulus provided during the pollen season. Transcriptomic analysis of allergen-specific T cells defined genes modulated in concomitance with the allergen exposure and inhibition of responses in non-allergic donors. CONCLUSION AND CLINICAL RELEVANCE: Magnitude and functionality of T helper cell responses differ substantially in season vs. out of season in allergic and non-allergic subjects. The results indicate the specific and opposing modulation of immune responses following the antigenic stimulation during the pollen season. This seasonal modulation reflects the enactment of specific molecular programmes associated with health and allergic disease.

Immunodominance in allergic T-cell reactivity to Japanese cedar in different geographic cohorts.

BACKGROUND: Japanese cedar (JC) pollen is a common trigger for allergic rhinitis in Japan. Pollen proteins targeted by IgE, including Cry j 1 and Cry j 2, and isoflavone reductase (IFR) have been identified. OBJECTIVE: To compare antigen-specific IgE titers and T-cell responses to JC pollen-derived extract and peptides in cohorts with high and low pollen exposure. METHODS: Peripheral blood mononuclear cells from JC pollen allergic or nonallergic patients who have lived in Japan for at least 1 year and JC pollen allergic patients who have never been to Japan were tested for T-cell responses against JC pollen extract and peptide pools derived from Cry j 1, Cry j 2, or IFR. T-cell reactivity was assessed by interleukin 5 and interferon γ production by ELISPOT. RESULTS: JC pollen-specific T-cell reactivity and IgE titers were significantly higher in the allergic compared with the nonallergic Japanese cohort, which was also associated with different patterns of polysensitization. Interestingly, a significant overlap was observed in the hierarchy of the T-cell epitopes in the allergic Japanese cohort compared with the allergic non-Japanese cohort. In all 3 cohorts, T-cell reactivity was dominantly directed against peptides from the major allergens Cry j 1 and 2, with few T-cell responses detected against IFR. CONCLUSION: Our studies identify common denominators of T-cell reactivity in patient populations with different sensitization patterns, suggesting that generally applicable immunotherapeutic approaches might be developed irrespective of exposure modality.

Children's respiratory health and oxidative potential of PM2.5: the PIAMA birth cohort study.

INTRODUCTION: The oxidative potential (OP) of particulate matter (PM) has been proposed as a health-relevant metric, but currently few epidemiological studies investigated associations of OP with health. Our main aim was to assess associations of long-term exposure to OP with respiratory health in children. Our second aim was to evaluate whether OP is more consistently associated with respiratory health than PM mass, PM composition or nitrogen dioxide (NO2). METHODS: For 3701 participants of a prospective birth cohort, annual average concentrations of OP (assessed by spin resonance (OP(ESR)) and dithiothreitol assay (OP(DTT))), PM with an aerodynamic diameter of less than 2.5 µm (PM2.5) mass, NO2, and PM2.5 constituents at the home addresses at birth and at all follow-up addresses were estimated by land-use regression. Repeated questionnaire reports of asthma and hay fever until age 14 years, and measurements of allergic sensitisation, lung function and fractional exhaled nitric oxide at age 12 years were linked with air pollution concentrations. RESULTS: Asthma incidence, prevalence of asthma symptoms and rhinitis were positively associated with OP(DTT) (adjusted OR (95% CI) per IQR increase in exposure 1.10 (1.01 to 1.20), 1.08 (1.02 to 1.16), 1.15 (1.05 to 1.26), respectively). These associations persisted after adjustment for most co-pollutants. Forced expiratory volume in 1s and forced vital capacity were negatively associated with OP(DTT). These associations were sensitive to adjustment for NO2. Respiratory health was not significantly associated with PM2.5 mass and OP(ESR). CONCLUSIONS: Respiratory health was more strongly associated with OP(DTT) than with PM2.5 mass; OP(DTT) associations with lung function, but not symptoms, were sensitive to adjustment for NO2.