IgE recognition of the house dust mite allergen Der p 37 is associated with asthma.

BACKGROUND: House dust mite (HDM) allergens are major elicitors of allergic reactions worldwide. OBJECTIVE: Identification, characterization, and evaluation of diagnostic utility of a new important HDM allergen was performed. METHODS: A cDNA coding for a new Dermatophagoides pteronyssinus (Dp) allergen, Der p 37, was isolated from a Dp expression library with allergic patients' IgE antibodies. Recombinant Der p 37 (rDer p 37) expressed in Escherichia coli was purified, then characterized by mass spectrometry, circular dichroism, and IgE reactivity by ImmunoCAP ISAC technology with sera from 111 clinically defined HDM-allergic patients. The allergenic activity of rDer p 37 was studied by basophil activation and CD4+ T-cell responses by carboxyfluorescein diacetate succinimidyl ester dilution assays. Specific antibodies raised against rDer p 37 were used for the ultrastructural localization of Der p 37 in mites by immunogold transmission electron microscopy. RESULTS: Der p 37, a 26 kDa allergen with homology to chitin-binding proteins, is immunologically distinct from Der p 15, 18, and 23. It is located in the peritrophic membrane of fecal pellets. Der p 37 reacted with IgE antibodies from a third of HDM-allergic patients and induced specific basophil- and CD4+ T-cell activation. Der p 37 IgE-positive patients had significantly higher IgE levels to major HDM allergens, reacted with more HDM allergens, and had a higher risk (odds ratio = 3.1) of asthma compared to Der p 37-negative patients. CONCLUSIONS: Der p 37, a new Dp allergen recognized by a third of HDM-allergic patients, may serve as a surrogate marker for severe HDM sensitization and asthma.

Technical standards in allergen exposure chambers worldwide - an EAACI Task Force Report.

Allergen exposure chambers (AECs) can be used for controlled exposure to allergenic and non-allergenic airborne particles in an enclosed environment, in order to (i) characterize the pathological features of respiratory diseases and (ii) contribute to and accelerate the clinical development of pharmacological treatments and allergen immunotherapy for allergic disease of the respiratory tract (such as allergic rhinitis, allergic rhinoconjunctivitis, and allergic asthma). In the guidelines of the European Medicines Agency for the clinical development of products for allergen immunotherapy (AIT), the role of AECs in determining primary endpoints in dose-finding Phase II trials is emphasized. Although methodologically insulated from the variability of natural pollen exposure, chamber models remain confined to supporting secondary, rather than primary, endpoints in Phase III registration trials. The need for further validation in comparison with field exposure is clearly mandated. On this basis, the European Academy of Allergy and Clinical Immunology (EAACI) initiated a Task Force in 2015 charged to gain a better understanding of how AECs can generate knowledge about respiratory allergies and can contribute to the clinical development of treatments. Researchers working with AECs worldwide were asked to provide technical information in eight sections: (i) dimensions and structure of the AEC, (ii) AEC staff, (iii) airflow, air processing, and operating conditions, (iv) particle dispersal, (v) pollen/particle counting, (vi) safety and non-contamination measures, (vii) procedures for symptom assessments, (viii) tested allergens/substances and validation procedures. On this basis, a minimal set of technical requirements for AECs applied to the field of allergology is proposed.

Fast effectiveness of a solubilized low-dose budesonide nasal spray in allergic rhinitis.

BACKGROUND: Budesonide, a poorly water-soluble corticosteroid, is currently marketed as a suspension. Budesolv is a novel aqueous formulation containing dissolved budesonide showing increased local availability in preclinical models. Budesolv contains ~85% less corticosteroid than the marketed comparator. OBJECTIVE: The study (EudraCT:2018-001324-19) was designed to assess non-inferiority of Budesolv compared to Rhinocort® Aqua 64 (RA) and early onset of action. METHODS: In a three-way cross-over double-blinded randomized trial, Budesolv 10 was compared to RA and placebo in grass pollen allergic rhinoconjunctivitis volunteers (n = 83 (ITT); n = 75 (PP)). On day 1, participants entered the Vienna Challenge Chamber (VCC) for 6 hours; first treatment took place at 1:45 hours after entry. Participants treated themselves for further 6 days; on day 8, the last treatment was applied before entering the VCC. Subjective symptom scores, nasal airflow and nasal secretion were measured regularly during allergen challenge. RESULTS: Budesolv 10 was equally effective compared to RA with respect to TNSS and nasal airflow after eight days of treatment with a strongly reduced dose (more than 80% reduction). After first dose, only Budesolv 10 showed a significant reduction of nasal and respiratory symptoms starting 90 minutes (P < .05) and 15 minutes (P < .05) after application onwards, respectively, demonstrating an early onset of efficacy. A clinically significant 1 point reduction in nasal symptom score was reached at 195 minutes (P < .05) after application. CONCLUSIONS AND CLINICAL RELEVANCE: The novel preservative-free, aqueous low-dose budesonide formulation is highly efficacious even after an initial single treatment. Thus, Budesolv 10 appears to be an effective acute treatment for allergic rhinitis as well as for AR comorbidities like mild asthma and conjunctivitis.

Randomized phase 1 study of the phosphatidylinositol 3-kinase δ inhibitor idelalisib in patients with allergic rhinitis.

BACKGROUND: Phosphatidylinositol 3-kinase p110δ isoform (PI3K p110δ) activity is essential for mast cell activation, suggesting that inhibition of PI3K p110δ might be useful in treating allergic diseases. OBJECTIVE: We sought to determine the effect of the PI3K p110δ-selective inhibitor idelalisib on allergic responses. METHODS: This phase 1 randomized, double-blind, placebo-controlled, 2-period crossover study was conducted with the Vienna Challenge Chamber. Grass pollen-induced allergic symptoms were documented during screening. Eligible subjects received idelalisib (100 mg twice daily) or placebo for 7 days, with allergen challenge on day 7. After a 2-week washout period, subjects received the alternate treatment and repeated allergen challenge. Study measures included safety, nasal and nonnasal symptoms, nasal airflow, nasal secretions, basophil activation, and plasma cytokine levels. RESULTS: Forty-one patients with allergic rhinitis received idelalisib/placebo (n = 21) or placebo/idelalisib (n = 20). Idelalisib treatment was well tolerated. Mean total nasal symptom scores were lower during the combined idelalisib treatment periods compared with placebo (treatment difference [idelalisib - placebo], -1.78; 95% CI, -2.53 to -1.03; P < .001). Statistically significant differences were also observed for the combined treatment periods for total symptom scores, nasal airflow, nasal secretion weight, and nasal congestion scores. The percentage of ex vivo-activated basophils (CD63(+)/CCR3(+) cells; after stimulation with grass pollen) was substantially lower for idelalisib-treated compared with placebo-treated subjects. Plasma CCL17 and CCL22 levels were reduced after idelalisib treatment. CONCLUSION: Idelalisib treatment was well tolerated in patients with allergic rhinitis and appears to reduce allergic responses clinically and immunologically after an environmental allergen challenge.

Long-term effects of a house dust mite sublingual immunotherapy tablet in an environmental exposure chamber trial.

BACKGROUND: Treatment with SQ house dust mite (HDM) sublingual immunotherapy (SLIT) tablet is effective for HDM respiratory allergic disease, but data on long-term effects are lacking. OBJECTIVE: Post hoc analyses were conducted to determine the long-term effect of SQ HDM SLIT-tablet on nasal, ocular, and cough symptoms 1 year after discontinuation of treatment. METHODS: Study participants underwent environmental exposure chamber (EEC) challenges at baseline and week 24 in a randomized, placebo-controlled, double-blind trial (NCT01644617) during which participants received daily 12 SQ-HDM, 6 SQ-HDM, or placebo for 24 weeks. Asthma had to be stable, well controlled, and nonsevere. The mean total asthma symptom score (TASS; sum of 3 symptoms: cough, wheeze, and dyspnea) during baseline and week 24 EEC challenge was analyzed in all participants who completed the trial (n = 106). Approximately 1 year after trial completion, another EEC challenge was conducted in a subset of participants (n = 51). Total nasal symptom score (sum of 4 symptoms), total ocular symptom score (sum of 2 symptoms), and cough were assessed. RESULTS: Compared with baseline and end-of-treatment values, sustained improvement of all symptoms assessed at the 1-year follow-up EEC challenge was evident in participants treated with 12 SQ-HDM. Results with 6 SQ-HDM were less notable. After 24 weeks of 12 SQ-HDM, TASS during EEC challenge was improved 65% vs baseline; at 1-year follow-up, cough was improved 57% vs baseline. CONCLUSION: Persistent improvement of nasal and ocular symptoms was observed up to 1 year after completing 24 weeks of 12 SQ-HDM treatment. Beneficial effects on cough were also observed. TRIAL REGISTRATION: clinicaltrials.gov Identifier NCT01644617.

Onset and dose-related efficacy of house dust mite sublingual immunotherapy tablets in an environmental exposure chamber.

BACKGROUND: The magnitude of effect of sublingual immunotherapy for house dust mite (HDM)-induced allergic rhinitis with or without conjunctivitis is uncertain, partly because there are few well-controlled trials with well-defined doses. OBJECTIVE: We sought to determine the dose-related efficacy and onset of action of the HDM sublingual immunotherapy tablet MK-8237 (Merck/ALK-Abelló) using the Vienna Challenge Chamber. METHODS: In this randomized, double-blind, single-site trial, adults with HDM-induced allergic rhinitis with or without conjunctivitis and with or without asthma (n = 124) received 12 developmental units (DU) of MK-8237, 6 DU of MK-8237, or placebo daily for 24 weeks. Subjects underwent 6-hour exposure challenges at screening and weeks 8, 16, and 24. The total nasal symptom score (TNSS) during chamber challenge at week 24 was the primary end point. The TNSS was the sum of 4 nasal symptom scores (maximum = 12). Total ocular symptom scores (TOSSs; 2 symptoms; maximum = 6) and total symptom scores (TSSs; TSS = TNSS plus TOSS; maximum = 18) were secondary end points. RESULTS: Dose- and time-dependent improvements with MK-8237 versus placebo were observed. At week 24, TNSS improvement relative to placebo was 48.6% (95% CI, 35.3% to 60.2%) with 12 DU of MK-8237 and 26.6% (95% CI, 11.2% to 39.6%) with 6 DU of MK-8237. Statistically significant improvements for TNSSs were also observed at weeks 8 (12 DU of MK-8237) and 16 (6 and 12 DU of MK-8237) and for TOSSs and TSSs by both doses at week 24. MK-8237 was well tolerated. No investigator-assessed anaphylactic allergic reactions or reactions requiring epinephrine were observed. CONCLUSIONS: MK-8237, 12 DU, reduced nasal and ocular symptoms and exceeded World Allergy Organization-established clinical efficacy criteria (≥20% improvement vs placebo). The onset of action for 12 DU of MK-8237 was week 8. MK-8237, 12 DU, is appropriate for further evaluation to determine the magnitude of effect in an uncontrolled allergen exposure environment.

Carrageenan-Containing Nasal Spray Alleviates Allergic Symptoms in Participants with Grass Pollen Allergy: A Randomized, Controlled, Crossover Clinical Trial.

Purpose: Nonpharmacological, barrier-forming nasal sprays are used to manage symptoms of allergic rhinitis. We aim to evaluate the safety and effectiveness of Callergin (investigational product, IP), a nasal spray containing barrier-forming iota-carrageenan, in the treatment of allergic rhinitis (AR). Methods: In this randomized, controlled, crossover trial, adults with grass pollen allergy underwent a treatment sequence with IP, VisAlpin (comparator product, CP), and no treatment in random order. Treatment blocks consisted in prophylactic administration of the assigned treatment or no treatment, followed by a 3-hr allergen exposure, and were separated by a washout period of 7 days. Primary endpoint was a mean change from baseline in "Total Nasal Symptom Score" (TNSS, sum of rhinorrhea, itching, sneezing, and congestion scores) over 3 hr, recorded every 15 min during the challenge period. Results: A total of 42 participants underwent randomization. Exposure to grass pollen for 3 hr induced a notable TNSS increase from baseline in all participants at all times. Mean TNSS change from baseline over 3 hr was lower when participants received IP compared to no treatment, although the difference did not reach statistical significance (untreated 6.96 ± 2.30; IP 6.59 ± 1.93; difference 0.37 points [95% CI (confidence interval) -0.17 to 0.91]; p=0.170). In a post-hoc analysis, mean TNSS at 3 hr was significantly reduced after IP treatment compared to no treatment (untreated 8.29 ± 2.64; IP 7.70 ± 2.56; difference 0.60 points [95% CI -0.10 to 1.29] p=0.028). While all individual nasal symptoms contributed to this effect, rhinorrhea (p=0.013) and congestion (p=0.076) contributed most. Consistently, nasal secretion weight was slightly reduced with IP treatment (p=0.119). IP was safe and well-tolerated, with similar incidence of adverse events across treatment groups. Conclusion: Prophylactic treatment with the iota-carrageenan nasal spray IP is safe, well-tolerated, and alleviates nasal allergy symptoms in adults with grass pollen-induced AR. Trial Registration: NCT04531358.

The effects of a TRPV1 antagonist, SB-705498, in the treatment of seasonal allergic rhinitis.

BACKGROUND: Current pharmacotherapy for allergic rhinitis (AR) does not totally ameliorate all symptoms for all patients. Residual symptoms could be due to nasal neuronal hyperresponsiveness caused by stimulation of the ion channel transient receptor potential vanilloid 1 (TRPV1). SB-705498 is a TRPV1 antagonist that has been developed in an intranasal formulation for treatment of AR. METHODS: This randomized, double-blind, 3-way incomplete block crossover study evaluated the effects of 8 days treatment with SB-705498 12 mg alone, SB-705498 12 mg plus fluticasone propionate 200 µg (FP), FP 200 µg alone or placebo on allergen-induced symptoms in 70 patients with AR. The primary endpoint was total nasal symptom score (TNSS), expressed as mean over 4 hours or maximum TNSS during allergen challenge in the Vienna Challenge Chamber on 8th day of treatment. RESULTS: At the end of treatment, there were no differences in allergen-induced mean TNSS between SB-705498 alone and placebo or between SB-705498 plus FP and FP alone. Treatment with FP and SB-705498 plus FP resulted in a significant decrease in TNSS vs. placebo. Mean (90% CI) treatment differences in TNSS over 0 - 4 hours were: SB-705498 - placebo: -0.2 (-0.9, 0.4); SB-705498 plus FP - FP: 0.7 (0.2, 1.2); FP - placebo: -2.9 (-3.4, -2.5); SB-705498 plus FP - placebo: -2.3 (-2.8, -1.8). SB-705498 had no impact on diary card symptoms, nasal airflow or Rhinoconjunctivitis Quality of Life Questionnaire scores. SB-705498 was well tolerated and pharmacokinetics exposure results supported the dosing regimen. CONCLUSION: SB-705498 12 mg for 8 days did not alleviate the allergen-induced symptoms of AR, or provide additional relief of symptoms when in combination with FP. Despite engagement of the TRPV1 receptor there was no translation to clinical efficacy, suggesting redundancy in symptom pathways.

Allergen challenge tests in allergen immunotherapy: State of the art.

INTRODUCTION: Treatment effects in allergen immunotherapy (AIT) studies are based on symptomatic improvement, and evaluations of naturally exposed patients do often show weak efficacy. Allergen challenge tests, such as conjunctival (CAC), nasal (NAC), or bronchial (BAC) challenge tests, or challenges in allergen exposure chambers (AEC) are accepted by regulators for AIT phase II studies only. MATERIALS AND METHODS: This review aims to describe different allergen challenge test methods, summarizes safety and limitations for each, and discusses their potential for use in AIT trials. RESULTS: Organ-specific allergen challenges provide information about individual reactivity, reaction threshold, and organ-specific efficacy of AIT. AECs, targeting all affected organs simultaneously, were developed to investigate disease mechanisms and treatment effects under controlled and reproducible conditions. CONCLUSION: A high level of standardization is existing for NAC only; in CAC and BAC, the toolbox is limited to subjective symptom scoring with no validated objective parameters identified yet. AECs are complex and heterogenous; correlation of systems and comparability of study data is claimed. All challenge methods are safe when conducted by experienced staff.

Expression in Escherichia coli and Purification of Folded rDer p 20, the Arginine Kinase From Dermatophagoides pteronyssinus: A Possible Biomarker for Allergic Asthma.

Arginine kinase (AK) was first identified as an allergen in the Indian-meal moth and subsequently shown to occur as allergen in various invertebrates and shellfish. The cDNA coding for AK from the house dust mite (HDM) species Dermatophagoides pteronyssinus, Der p 20, has been isolated, but no recombinant Der p 20 (rDer p 20) allergen has been produced and characterized so far. We report the expression of Der p 20 as recombinant protein in Escherichia coli. rDer p 20 was purified and shown to be a monomeric, folded protein by size exclusion chromatography and circular dichroism spectroscopy, respectively. Using AK-specific antibodies, Der p 20 was found to occur mainly in HDM bodies, but not in fecal particles. Thirty percent of clinically well-characterized HDM allergic patients (n = 98) whose immunoglobulin E (IgE) reactivity profiles had been determined with an extensive panel of purified HDM allergens (Der f 1, 2; Der p 1, 2, 4, 5, 7, 10, 11, 14, 15, 18, 21, 23 and 37) showed IgE reactivity to Der p 20. IgE reactivity to Der p 20 was more frequently associated with lung symptoms. AKs were detected in several invertebrates with specific antibodies and Der p 20 showed IgE cross-reactivity with AK from shrimp (Litopenaeus vannamei). Thus, Der p 20 is a cross-reactive HDM allergen and may serve as a diagnostic marker for HDM-induced lung symptoms such as asthma.

IgE Epitopes of the House Dust Mite Allergen Der p 7 Are Mainly Discontinuous and Conformational.

Background: Several studies indicate that Der p 7 is an important and clinically relevant allergen of Dermatophagoides pteronyssinus which should be included in vaccines for treatment of house dust mite (HDM) allergy. Aim of this study was to characterize the IgE epitopes of Der p 7. Methods: Recombinant Der p 7 was expressed and purified, analyzed for fold by circular dichroism and tested for its allergenic activity by basophil activation. Seven overlapping, surface-exposed peptides (P1-P7) with a length of 27 to 37 amino acids, which spanned the Der p 7 sequence, were synthesized and tested for IgE reactivity and allergenic activity by basophil activation assay. Carrier-bound peptides were studied for their ability to induce allergen-specific IgG antibodies in rabbits. Peptide-specific antibodies were used to inhibit allergic patients` IgE binding to Der p 7 by ELISA for mapping of IgE epitopes. Results: rDer p 7 showed high allergenic activity comparable with Der p 5, Der p 21, and Der p 23. None of the seven tested peptides showed any IgE reactivity or allergenic activity when tested with HDM- allergic patients indicating lack of sequential IgE epitopes on Der p 7. IgE inhibition experiments using anti-peptide specific IgGs and molecular modeling enabled us to identify discontinuous, conformational IgE epitopes of Der p 7. Conclusion and Clinical Relevance: IgE epitopes of Der p 7 belong to the conformational and discontinuous type whereas sequential Der p 7 peptides lack IgE reactivity. It should thus be possible to construct hypoallergenic vaccines for Der p 7 based on carrier-bound allergen peptides.

The effects of bilastine compared with cetirizine, fexofenadine, and placebo on allergen-induced nasal and ocular symptoms in patients exposed to aeroallergen in the Vienna Challenge Chamber.

OBJECTIVE AND DESIGN: This double-blind cross-over study compared the potential of bilastine, cetirizine, and fexofenadine to relieve the symptoms of allergic rhinitis. SUBJECTS AND METHODS: Seventy-five allergic volunteers were challenged with grass pollen in the Vienna Challenge Chamber (VCC) on two consecutive days of allergen provocation; 6 h on day 1 and 4 h day 2. Bilastine 20 mg, cetirizine 10 mg, fexofenadine 120 mg, or placebo were taken orally 2 h after the start of provocation on day 1 only. Total nasal symptom scores, the global symptom scores, nasal secretions, and eye symptoms were assessed on both day 1 and day 2. RESULTS AND CONCLUSIONS: Bilastine had a rapid onset of action, within 1 h, and a long duration of action, greater than 26 h. Cetirizine was similar. Fexofenadine was similar on day 1 but less effective on day 2, indicating a shorter duration of action. Bilastine, like cetirizine and fexofenadine, was safe and well tolerated in this study.

Early onset of action of a 5-grass-pollen 300-IR sublingual immunotherapy tablet evaluated in an allergen challenge chamber.

BACKGROUND: The efficacy and safety of a 5-grass-pollen sublingual immunotherapy (SLIT) tablet (Stallergènes SA, Antony, France) have been evaluated in clinical studies during the pollen season. The allergen challenge chamber (ACC) has been developed as a pharmacodynamic assessment tool to control the environmental allergens and to avoid all problems associated with unpredictable pollen seasons. OBJECTIVE: We sought to evaluate the onset of action and efficacy of 300-IR (index of reactivity) SLIT tablets by using an ACC. METHODS: Patients with grass pollen-induced rhinoconjunctivitis were randomized into the active or placebo groups. A standardized allergen challenge with grass pollen and symptom evaluation every 15 minutes was performed at baseline, 1 week, and 1, 2, and 4 months of treatment. The primary end point was the average rhinoconjunctivitis total symptom score (ARTSS). Allergen-specific basophil activation, T-cell proliferation, and plasmatic IgE and IgG responses were assessed before and after treatment. RESULTS: In the intention-to-treat population (n = 89) a significant treatment effect was achieved after the first month (P = .0042) and second month (P = .0203) and was maintained through to the fourth month (P = .0007). In the active group the ARTSS (means +/- SDs) decreased at each challenge: week 1, 7.40 +/- 2.682; month 1, 5.89 +/- 2.431; month 2, 5.09 +/- 2.088; and month 4, 4.85 +/- 1.999. An improvement (vs placebo) of 29.3% for the mean ARTSS (median, 33.3%) was observed at end point. Furthermore, the induction of grass pollen allergen-specific IgGs was associated with clinical response. The most frequent adverse reactions were local: oral pruritus, ear pruritus, and throat irritation. CONCLUSIONS: In this ACC study the 300-IR 5-grass-pollen SLIT tablets had a significant effect on rhinoconjunctivitis symptoms (vs placebo) from the first month of treatment onward.

Quantification, epitope mapping and genotype cross-reactivity of hepatitis B preS-specific antibodies in subjects vaccinated with different dosage regimens of BM32.

BACKGROUND: Chronic hepatitis B virus (HBV) infections are a global health problem. There is a need for therapeutic strategies blocking continuous infection of liver cells. The grass pollen allergy vaccine BM32 containing the preS domain of the large HBV surface protein (LHBs) as immunogenic carrier induced IgG antibodies in human subjects inhibiting HBV infection in vitro. Aim of this study was the quantification, epitope mapping and investigation of HBV genotype cross-reactivity of preS-specific antibodies in subjects treated with different dosage regimens of BM32 METHODS: Hundred twenty eight grass pollen allergic patients received in a double-blind, placebo-controlled trial five monthly injections of placebo (aluminum hydroxide, n= 34) or different courses of BM32 (2 placebo + 3 BM32, n= 33; 1 placebo + 4 BM32, n= 30; 5 BM32, n= 31). Recombinant Escherichia coli-expressed preS was purified. Overlapping peptides spanning preS and the receptor-binding sites from consensus sequences of genotypes A-H were synthesized and purified. Isotype (IgM, IgG, IgA, IgE) and IgG subclass (IgG1-IgG4) responses to preS and peptides were determined by ELISA at baseline, one and four months after the last injection. IgG1 and IgG4 subclass concentrations specific for preS and the receptor-binding site were measured by quantitative ELISA. FINDINGS: Five monthly injections induced the highest levels of preS-specific IgG consisting mainly of IgG1 and IgG4, with a sum of median preS-specific IgG1 and IgG4 concentrations of >135 µg/ml reaching up to 1.8 mg/ml. More than 20% of preS-specific IgG was directed against the receptor-binding site. BM32-induced IgG cross-reacted with the receptor-binding domains from all eight HBV genotypes A-H. INTERPRETATION: BM32 induces high levels of IgG1 and IgG4 antibodies against the receptor binding sites of all eight HBV genotypes and hence might be suitable for therapeutic HBV vaccination. FUNDING: This study was supported by the PhD program IAI (KPW01212FW), by Viravaxx AG and by the Danube-ARC funded by the Government of Lower Austria. Rudolf Valenta is a recipient of a Megagrant of the Government of the Russian Federation, grant No 14.W03.31.0024.

Clinical efficacy of sublingual immunotherapy is associated with restoration of steady-state serum lipocalin 2 after SLIT: a pilot study.

BACKGROUND: So far, only a few biomarkers in allergen immunotherapy exist that are associated with a clinical benefit. We thus investigated in a pilot study whether innate molecules such as the molecule lipocalin-2 (LCN2), with implications in immune tolerance demonstrated in other fields, may discriminate A) between allergic and non-allergic individuals, and B) between patients clinically responding or non-responding to sublingual allergen immunotherapy (SLIT) with house dust mite (HDM) extract. Moreover, we assessed haematological changes potentially correlating with allergic symptoms. METHODS: LCN2-concentrations were assessed in sera of healthy and allergic subjects (n = 126) as well as of house dust mite (HDM) allergics before and during HDM- sublingual immunotherapy (SLIT) in a randomized, double-blind, placebo-controlled trial for 24 weeks. Sera pre-SLIT (week 0), post-SLIT (week 24) and 9 months after SLIT were assessed for LCN2 levels and correlated with total nasal symptom scores (TNSS) obtained during chamber challenge at week 24 in patients receiving HDM- (n = 31) or placebo-SLIT (n = 10). RESULTS: Allergic individuals had significantly (p < 0.0001) lower LCN2-levels than healthy controls. HDM-allergic patients who received HDM-SLIT showed a significant increase in LCN2 9 months after termination of HDM-SLIT (p < 0.001), whereas in subjects receiving placebo no increase in LCN2 was observed. Among blood parameters a lower absolute rise in the lymphocyte population (p < 0.05) negatively correlated with symptom improvement (Pearson r 0.3395), and a lower relative increase in the neutrophils were associated with improvement in TNSS (p < 0.05). LCN2 levels 9 months after immunotherapy showed a low positive correlation with the relative improvement of symptoms (Pearson r 0.3293). LCN2-levels 9 months off-SLIT were significantly higher in patients whose symptoms improved during chamber challenge than in those whose symptoms aggravated (p < 0.01). CONCLUSION: Serum LCN2 concentrations 9 months off-SLIT correlated with clinical reactivity in allergic patients. An increase in the LCN2 levels 9 months after HDM-SLIT was associated with a clinical benefit. Serum LCN2 may thus contribute to assess clinical reactivity in allergic patients. TRIAL REGISTRATION: Part of the data were generated from clinicaltrials.gov Identifier NCT01644617.

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.

Azelastine nasal spray and desloratadine tablets in pollen-induced seasonal allergic rhinitis: a pharmacodynamic study of onset of action and efficacy.

OBJECTIVE: To assess the efficacy and onset of action of azelastine nasal spray and desloratadine tablets in patients with allergen-induced seasonal allergic rhinitis (SAR). RESEARCH DESIGN AND METHODS: 46 adult patients with a history of SAR were exposed to a controlled grass pollen concentration for 6 h in the Vienna Challenge Chamber (VCC) in each treatment period according to a randomised, double-blind (double-dummy), three-period, three-sequence crossover design (wash-out period of 12 days). Single doses of study medication (one puff nasal spray into each nostril of azelastine, 0.2 mg, or placebo before swallowing one encapsulated tablet of desloratadine, 5 mg) were administered 2 h after the start of the allergen challenge. Results of subjective and objective assessments were recorded throughout the challenge. RESULTS: Efficacy of azelastine nasal spray was significantly superior compared to desloratadine tablets (p = 0.005) and placebo (p < 0.001). Desloratadine was significantly better than placebo (p < 0.001). Decrease both in Major Nasal Symptom Score (MNSS) and in Total Nasal Symptom Score (TNSS) was fastest after azelastine treatment. Improvement of nasal symptom severity was most pronounced after azelastine treatment for all nasal symptoms including nasal congestion. Onset of action was 15 min for azelastine compared to 150 min for desloratadine. Both active preparations were safe and well tolerated. CONCLUSIONS: This study confirms the usefulness of azelastine nasal spray for the symptomatic treatment of seasonal allergic rhinitis. Concerning onset of action in particular, the results favour the topical treatment over systemic therapy.