BACKGROUND:Allergen immunotherapy (AIT) is the only disease-modifying therapeutic approach for cat allergy, though it requires at least three years of treatment and can potentially induce severe systemic reactions. Plant-derived bioparticles expressing Fel d 1 allergen (Fel d 1 eBP) have been developed as a novel therapeutic candidate for cat allergy. We aimed to investigate the allergenicity and immunogenicity profile of Fel d 1 eBP. METHODS:Fel d 1 eBP was synthesised in vivo in Nicotiana benthamiana and confirmed by cryo-electron microscopy and tomography. Immune modulatory properties of purified natural Fel d 1 (nFel d 1) and Fel d 1 eBP were assessed at T and B cells by flow cytometry in 12 cat-allergic subjects (CA) and 12 non-atopic controls (NAC). Single-cell RNA-seq was used to assess molecular mechanisms of Fel d 1 eBP immune skewing. The safety of Fel d 1 eBP was assessed by measuring basophil responsiveness in whole blood and further confirmed in vivo by its administration as a skin prick test (SPT) in 20 cat-allergic individuals. RESULTS:Fel d 1 eBP was shown to be a strong inducer of Th1 cells (p < 0.05) and IL-10+ non-Th2 cells (p < 0.05) in CA subjects. Fel d 1 eBP showed a stronger trend for inducing IL-10+ Breg cells compared to nFel d 1, peaking at 3 μg/mL. scRNA-seq analyses demonstrated that Fel d 1 eBP targets the induction of protective metallothionein genes, CCL18+ monocytes and naïve B cells that are interferon responsive and metabolically activated. Moreover, Fel d 1 eBP demonstrated reduced capacity to elicit basophil activation (p < 0.001) and histamine release (p < 0.01), indicating their hypoallergenic nature. Administration of titrated doses of Fel d 1 eBP through skin prick test revealed that they are well-tolerated with reduced mean wheal compared to native Fel d 1 in an open-label Phase 0 study (all, p < 0.001). CONCLUSIONS:We demonstrate that Fel d 1 eBP is hypoallergenic and demonstrates tolerogenic properties, making it a novel candidate for use in AIT for cat allergy.

AbstractBackgroundNasal allergen challenge (NAC) is used to investigate the effects of allergen exposure and assess treatment efficacy in allergic rhinitis (AR). This study aims to establish dose‐responses to NAC using licensed silver birch (SB) pollen and house dust mite (HDM) sublingual tablets as sources of the allergen extracts in participants with AR.MethodsSixteen volunteers with HDM‐induced perennial AR and 15 volunteers with SB pollen‐induced seasonal rhinitis underwent a graded up‐dosing NAC with extracts derived from HDM allergen (Acarizax®) and SB (Itulazax®) tablets, respectively. Total nasal symptom score (TNSS, range 0–12) and peak nasal inspiratory flow (PNIF) were recorded before, at 10 min and at the end of the NAC. The dose of each allergen that provoked a TNSS of at least 7 (“provoking dose 7”) in most allergic participants was identified. NACs using the “provoking dose 7” were performed on 5 non‐allergic individuals to test for irritant effects. The “provoking dose 7” of HDM extract was used in a subgroup of two SB allergic, non‐HDM allergic, volunteers, and vice versa for SB extract, to test for allergen specificity of the responses.ResultsMost patients experienced a TNSS of at least 7/12 at a median concentration of 1500 AU/mL for both SB pollen and HDM. The average decline in PNIF at this dose was 63.15% for SB and 63.99% for HDM. NACs using the 1500 AU/mL concentrations were performed on 5 non‐allergic individuals with no symptomatic or PNIF response. 1500 AU/mL of HDM extract produced no symptoms in SB allergics nor 1500 AU/mL SB extract in HDM allergics.ConclusionFor both SB and HDM extracts, the optimal allergen dose for NAC to cause a moderate‐severity response (“provoking dose 7/12”) was 1500 AU/mL. Licensed sublingual allergen tablets provide a readily available and inexpensive source of SB and HDM extracts for use in future interventional studies in AR.

Nichols’ (6) recent article in the journal succinctly reviews a broad range of conditions that should be considered by those delivering medical care to aquatic athletes. The review covers airway disease and, more specifically, exercise-induced bronchoconstriction (EIB). However, we wish to highlight a number of important omissions relating to the assessment of the upper airway, an important aspect of care often overlooked by clinicians. Studies have demonstrated high rates of rhinitis in elite swimmers (2,5). Both symptoms and impairment of quality of life (if not performance) are greatest during periods of intense training and appear to decrease during prolonged rest periods away from the pool (2). Although atopy is at least as common in elite swimmers as age-matched controls, both allergic and nonallergic pathologies may be relevant (4). Falls in nasal peak inspiratory flow are seen after swimming (1); swimmers also have been found to have prolonged mucociliary clearance times, and notably, rhinitis in elite swimmers is likely to be undertreated (2,5). It is also becoming increasingly well recognized that many athletes diagnosed with EIB also have exercise-induced laryngeal obstruction (EILO), a transient narrowing of the upper airways, at the level of the voice box that develops during maximal exercise (7). This acts to generate airway turbulence and increase airflow resistance, thereby causing discomfort and impaired exercise performance. An accurate assessment of the prevalence of this condition in aquatic athletes has been hampered by the obvious difficulties in performing the gold standard test of continuous laryngoscopy during exercise in the pool environment. However, it is our experience that EILO frequently coexists with EIB in elite swimmers. Poolside assessment facilitates diagnosis, and pointers to the diagnosis include the presence of wheeze, of stridulous quality, that occurs at peak exercise and rapidly abates on exercise cessation. It is our experience that EILO in aquatic athletes responds well to work with a combination of inspiratory muscle and breathing relaxation training (3). Overall, we urge clinicians to consider the entire airway tract when assessing respiratory health in aquatic athletes and believe this approach is vitally important to ensure that both health and performance of this group of athletes are optimized. James H. Hull, PhD Department of Respiratory Medicine Royal Brompton Hospital London, UK [email protected] Guy Scadding Department of Respiratory Medicine Royal Brompton Hospital London, UK John Dickinson Endurance Research Group School of Sport and Exercise Sciences University of Kent Kent, UK Jon Greenwell British Swimming Loughborough, UK The authors declare no conflicts of interest and do not have any financial disclosures.

Several studies have demonstrated the time course of inflammatory mediators in nasal fluids following nasal allergen challenge (NAC), whereas the effects of NAC on cells in the periphery are unknown. We examined the time course of effector cell markers (for basophils, dendritic cells and T cells) in peripheral blood after nasal grass pollen allergen challenge.

Participant dropouts can reduce the power of allergen immunotherapy clinical trials. Evaluation of the dropout rate and reasons for dropout are important not only in the planning of clinical studies but are also relevant for adherence to immunotherapy in daily clinical practice. A systematic review was carried out in order to establish the overall dropout rate among published double-blind, placebo-controlled randomized clinical trials of sublingual immunotherapy for respiratory allergic diseases. Dropouts were analysed in regards to allergen, formulation, treatment schedule, participant age, study size, number of centres and type of allergic disease. Relative dropout rates in placebo and active groups as well as reasons for dropout were also assessed. A total of 81 studies, comprising 9998 patients, were included. Dropout rates in sublingual immunotherapy controlled studies do not appear to be a major problem with a composite dropout percentage of 14% (95% CI:11.9-16). Furthermore, they are not different for active compared to placebo-treated participants. This lends support to the positive clinical outcomes seen in meta-analyses of these trials.

Regulatory T cells maintain peripheral tolerance to allergens in non-atopic individuals. IL-35 is a novel cytokine consisting of EBI3 and p35 subunit of IL-12. Recent studies have revealed IL-35 in regulating immunologic responses through induction of inducible IL-35-producing Treg cells. We hypothesized that IL-35 suppresses T effector (Teff) functions. We further hypothesized that IL-35 suppresses grass pollen-specific Th2 responses following in-vitro stimulation. CD4+CD25- T effector cells were purified from PBMCs (8 non-atopic and 7 grass pollen allergics) by magnetic separation. Teff cells were stimulated with anti-CD3/CD28 +/- rhIL-35:Fc for 6 days. The effect of rhIL-35:fc on grass pollen-specific Teff cell proliferative responses (n=6) was assessed. Gene expression was assessed by RT-PCR. A dose-dependent suppression of anti-CD3/CD28-stimulated CD4+CD25- Teff cell proliferation was demonstrated. This suppression was optimal at 10ng/mL of rhIL-35:Fc (n=15; p<0.005) and was associated with increases in relative gene expression of EBI3 (p=0.03), IL-12p35 (p=0.02), IL-12p28 (p=0.02), IFN-γ (p=0.02), FoxP3 (p=0.03) but not IL-10. A downward trend in IL-4 mRNA was demonstrated (p=0.06). An increase in CD4+CD25hiFoxp3+ (p=0.04) and CD4+CD25+TGF-β+ (p=0.009) T cells was demonstrated in the presence of IL-35; however, PBMC proliferative responses were not affected. Timothy grass pollen-driven CD4+CD25- Teff cell proliferative responses (n=6; p=0.03) and Th2 cytokine production (IL-4, p=0.03; IL-9, p=0.03 and IL-13, p=0.02) were suppressed by rhIL-35. IL-35 supresses antigen-specific T cell responses and is associated with the induction of CD4+CD25hiFoxp35+ and inducible IL-35+CD4+CD25+ (EBI3+IL-12p35+) Tregs. The mechanisms by which iIL35 Treg cells immunomodulate Th2 responses remains to be fully determined.

A 48-year old woman presented with a 10-year history of rapid-onset adverse reactions to foods. Reactions involved discomfort in the lips, throat and tongue, throat tightness, an urticarial rash, and a 'sensation of doom'. Suspect triggers included butter toffee popcorn, the aperitif Pernod, cinnamon, toffee apples, ginger nut biscuits, honeycomb confectionary and a supermarket pizza. Additionally, she described contact hypersensitivity to jewellery and cosmetics. Certain soaps and household detergents also provoked urticaria. Skin tests and ImmunoCAP tests to aeroallergens and food allergens were negative; prick-prick testing to the same popcorn was also negative. Nonetheless, we felt her history was convincing, and were suspicious of a linking factor between the identified triggers. We subsequently referred her for patch testing. Patch tests produced a rapid onset urticarial response to myroxylon sulphate (Balsam of Peru); the delayed response was negative. Delayed responses were positive to nickel sulphate and Fragrance mix 1 and 2. We conclude that our patient had an acute-onset hypersensitivity to Balsam of Peru, an aromatic liquid derived from the Myroxolon balsamum tree used in cosmetics, foods, beverages and medicinal products. It contains cinnamic acid, cinnamyl cinnamate, benzyl benzoate, benzoic acid and vanilla, as well as essential oils similar to those found in citrus fruit peel. It most commonly causes a contact dermatitis; highly allergic individuals may suffer adverse reactions after consuming foods containing Balsam of Peru including soreness of the tongue and mouth. Implicated foods include spices, citrus fruit peel, baked goods, aperitifs, benzoic acid and related preservatives. Our patient is unusual in presenting with acute symptoms, mimicking IgE-mediated allergy. Of note, contact urticarial reactions have previously been described to patch testing with Balsam of Peru; the mechanism of such reactions is unclear. Clinicians should be aware of non-classical food ‘allergic’ reactions, especially to pre-prepared foods with complex ingredients.

Clinical & Experimental AllergyVolume 40, Issue 9 p. 1432-1432 Response by Stephen R. Durham and G.W. Scadding S. R. Durham, S. R. Durham Allergy and Clinical Immunology Section, National Heart & Lung Institute, Imperial College London, London SW7 2AZ, UK E-mail: s.durham@imperial.ac.ukSearch for more papers by this authorG.W. Scadding, G.W. Scadding Allergy and Clinical Immunology Section, National Heart & Lung Institute, Imperial College London, London SW7 2AZ, UK E-mail: s.durham@imperial.ac.ukSearch for more papers by this author S. R. Durham, S. R. Durham Allergy and Clinical Immunology Section, National Heart & Lung Institute, Imperial College London, London SW7 2AZ, UK E-mail: s.durham@imperial.ac.ukSearch for more papers by this authorG.W. Scadding, G.W. Scadding Allergy and Clinical Immunology Section, National Heart & Lung Institute, Imperial College London, London SW7 2AZ, UK E-mail: s.durham@imperial.ac.ukSearch for more papers by this author First published: 04 August 2010 https://doi.org/10.1111/j.1365-2222.2010.03579_1.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume40, Issue9September 2010Pages 1432-1432 RelatedInformation