Major Allergen Content in Allergen Immunotherapy Products: The Limited Value of Numbers.

The prevalence of allergic disorders has increased drastically over the last 50 years to the extent that they can be considered epidemic. At present, allergen-specific immunotherapy (AIT) is the only therapy that targets the underlying cause of allergic disorders, and evidence of its superiority is based on data accumulated from clinical trials and observational studies demonstrating efficacy and safety. However, several aspects remain unresolved, such as harmonization and standardization of manufacturing and quantification procedures across manufacturers, homogeneous reporting of strength, and the establishment of international reference standards for many allergens. This article discusses issues related to the measurement of major allergen content in AIT extracts, raising the question of whether comparison of products from different manufacturers is an appropriate basis for selecting a specific AIT product. Allergen standardization in immunotherapy products is critical for ensuring quality and, thereby, safety and efficacy. However, lack of harmonization in manufacturing processes, allergen quantification (methodologies and references), national regulatory differences, clinical practice, and labeling shows that the comparison of AIT products based solely on major allergen amounts is not rational and, in fact, impossible. Moreover, when rating the information given for a specific product, it is necessary to take into account further inherent characteristics of products and their application in clinical practice, such as the state of extract modification, addition of adjuvant or adjuvant system, route of administration (sublingual/ subcutaneous), and cumulative dose as per posology (including the volume per administration). Finally, only convincing clinical data can serve as the basis for product-specific evaluation and cross-product comparability of individual products.

Major Allergen Content in Allergen Immunotherapy Products: The Limited Value of Numbers

The prevalence of allergic disorders has increased drastically over the last 50 years to the extent that they can be considered epidemic.At present, allergen-specific immunotherapy (AIT) is the only therapy that targets the underlying cause of allergic disorders, and evidenceof its superiority is based on data accumulated from clinical trials and observational studies demonstrating efficacy and safety. However,several aspects remain unresolved, such as harmonization and standardization of manufacturing and quantification procedures acrossmanufacturers, homogeneous reporting of strength, and the establishment of international reference standards for many allergens. Thisarticle discusses issues related to the measurement of major allergen content in AIT extracts, raising the question of whether comparison ofproducts from different manufacturers is an appropriate basis for selecting a specific AIT product. Allergen standardization in immunotherapyproducts is critical for ensuring quality and, thereby, safety and efficacy. However, lack of harmonization in manufacturing processes,allergen quantification (methodologies and references), national regulatory differences, clinical practice, and labeling shows that thecomparison of AIT products based solely on major allergen amounts is not rational and, in fact, impossible. Moreover, when rating theinformation given for a specific product, it is necessary to take into account further inherent characteristics of products and their applicationin clinical practice, such as the state of extract modification, addition of adjuvant or adjuvant system, route of administration (sublingual/subcutaneous), and cumulative dose as per posology (including the volume per administration). Finally, only convincing clinical data canserve as the basis for product-specific evaluation and cross-product comparability of individual products. (AU)

La prevalencia de las enfermedades alérgicas se ha incrementado drásticamente en los últimos 50 años y hoy pueden considerarse unaepidemia. Actualmente, la inmunoterapia específica con alérgenos (ITA) es el único tratamiento dirigido a la causa subyacente de lasenfermedades alérgicas y su superioridad se basa en resultados de ensayos clínicos/estudios observacionales que demuestran su eficaciay seguridad. Pero quedan aspectos sin resolver, como la armonización y estandarización de los procesos de fabricación y cuantificaciónentre fabricantes, la declaración homogénea de la potencia y el establecimiento de estándares internacionales de referencia. En este artículo se discuten aspectos relacionados con la medida del contenido de alérgenos mayores en los extractos de ITA, cuestionandosi, como base para elegir entre productos, es apropiada la comparación entre diferentes fabricantes. La estandarización alergénica escrucial para asegurar la calidad y, por tanto, la seguridad y eficacia de la ITA. Sin embargo, la falta de armonización en los procesos defabricación, la cuantificación alergénica, las diferencias regulatorias, la práctica clínica y el etiquetado, demuestran que comparar productosbasándose únicamente en la cantidad de alérgeno mayor no está justificado y es imposible. Además, cuando se evalúa la informaciónpara un determinado producto, deben tenerse en cuenta las características propias de cada producto y su uso clínico, como el estado dela modificación del extracto, la adición de adyuvantes, la vía de administración y la dosis acumulada. Solo datos clínicos convincentesdeben servir para la evaluación específica de cada producto o como base para la comparación entre productos. (AU)

AllergoOncology: ultra-low IgE, a potential novel biomarker in cancer-a Position Paper of the European Academy of Allergy and Clinical Immunology (EAACI).

Elevated serum IgE levels are associated with allergic disorders, parasitosis and specific immunologic abnormalities. In addition, epidemiological and mechanistic evidence indicates an association between IgE-mediated immune surveillance and protection from tumour growth. Intriguingly, recent studies reveal a correlation between IgE deficiency and increased malignancy risk. This is the first review discussing IgE levels and links to pathological conditions, with special focus on the potential clinical significance of ultra-low serum IgE levels and risk of malignancy. In this Position Paper we discuss: (a) the utility of measuring total IgE levels in the management of allergies, parasitosis, and immunodeficiencies, (b) factors that may influence serum IgE levels, (c) IgE as a marker of different disorders, and d) the relationship between ultra-low IgE levels and malignancy susceptibility. While elevated serum IgE is generally associated with allergic/atopic conditions, very low or absent IgE may hamper anti-tumour surveillance, indicating the importance of a balanced IgE-mediated immune function. Ultra-low IgE may prove to be an unexpected biomarker for cancer risk. Nevertheless, given the early stage of investigations conducted mostly in patients with diseases that influence IgE levels, in-depth mechanistic studies and stratification of malignancy risk based on associated demographic, immunological and clinical co-factors are warranted.

Cetirizine inhibits gender-specific blood cell dynamics upon allergen contact in allergic rhinitis.

IgE-mediated inflammatory responses upon allergen contact in allergic rhinitis (AR) are associated with rapid alterations of circulating blood cell numbers detectable in a complete blood count (CBC). Aim of this study was to evaluate whether intake of antihistamines may modulate allergen-induced CBC dynamics in male and female patients. A total of N = 112 specific allergen challenges were performed in otherwise healthy AR subjects. Seventy-two (n = 72) subjects received placebo and forty (n = 40) received cetirizine (H1-receptor antagonist) per os prior to allergen exposure in a randomized, double-blind trial at the Vienna Challenge Chamber (VCC); a subgroup of twenty-five (n = 25) subjects received cetirizine and placebo on different study days (parallel group). Blood samples and symptom scores were taken at baseline and immediately after 6 h of airway challenge simulating ambient allergen contact. Female sex was associated with a pronounced circulating monocyte increase (p < .01) and male sex with an eosinophil decrease (p < .05) in the placebo group, but not in cetirizine treated subjects. The significant increase in segmented neutrophils (p < .001) and decrease in circulating erythrocytes (p < .01) upon allergen challenge was less prominent after cetirizine intake in both sexes. A more prominent thrombocyte increase in female subjects (p < .05) was noted upon allergen exposure, regardless of prior cetirizine intake. Cetirizine inhibited the mobilization of neutrophils, lymphocytes and decline in erythrocyte numbers, but did not affect thrombocyte increase upon allergen challenge. It further diminished gender-specific blood cell dynamics. Overall, as reflected in a simple CBC, cetirizine critically diminished immediate and late innate immune responses subsequent to allergen exposure.

Salivary cortisol responses to acute stress vary between allergic and healthy individuals: the role of plasma oxytocin, emotion regulation strategies, reported stress and anxiety.

Numerous studies have demonstrated that acute psychological stress, induced by the Trier Social Stress Test (TSST) paradigm, affects salivary cortisol secretion and self-reported stress measures including anxiety. Allergy has been related to altered cortisol responsiveness and increased stress vulnerability. Here, we investigated acute stress responses and emotion regulation strategies in cohorts of allergic and healthy individuals. Groups of allergics and healthy individuals were subjected to the TSST and experienced levels of stress and anxiety, as well as emotion regulation strategies, were assessed. Cortisol and oxytocin concentrations were measured in saliva or plasma. The present findings confirm earlier results of altered stress responsiveness in allergic individuals. Acute stress by the TSST evoked higher physiological arousal in allergics by means of salivary cortisol secretion. Allergics also scored higher on emotion suppression. However, individuals who were more likely to use reappraisal recovered more efficiently from the cortisol increase. No such effect for reappraisal was found in the healthy population. No differences in self-reported anxiety and stress emerged between the groups. Plasma oxytocin levels prior to the TSST were significantly higher in allergics. Our data corroborate earlier findings on altered stress susceptibility in allergics. Moreover, we identified differences in emotion regulation and oxytocin secretion which should be further explored. Accounting for the emerging global prevalence of allergy, more in-depth research into the experience of stress, coping strategies and stress-related molecules in allergic people is warranted.Short summaryThis study addressed stress experiences and emotion regulation in allergic and non-allergic adults. Allergics scored higher on emotion suppression, had higher pre-stress concentrations of plasma oxytocin and exhibited a stronger salivary cortisol response to stress than healthy people. The research outcomes indicate that allergic individuals cope less efficiently with acute stress but may benefit from adaptive emotion regulation strategies such as reappraisal.

Allergy diagnosis from symptoms to molecules, or from molecules to symptoms: a comparative clinical study.

BACKGROUND: Classical allergy diagnostic workup "from symptoms to molecules" comprises 1) clinical investigation, 2) skin prick- and IgE- testing, and recently, 3) molecular allergy testing. We aimed to examine the diagnostic fidelity of the alternative approach "from molecules to symptoms", which was recently suggested in the EAACI Molecular Allergology User's Guide, in a retrospective clinical study. METHODS: Records from 202 patients with clinically suspected allergic sensitizations were extracted from files at two sites applying either the "ISAC-first" workup with IgE-testing by immuno-solid phase allergen chip ISAC112 followed by selected skin prick tests (SPT) or the "SPT-first" starting with SPT followed by the microarray test. RESULTS: In the ISAC-first procedure significantly less SPTs were performed during allergy diagnosis (median 4 vs. 14). By SPT in 19% of patients in the ISAC-first group and in 34% in the SPT-first group additional respiratory allergens (p = 0.014) were detected not positive in ISAC microarray. By ISAC microarray test 18% additional sensitizations were found in the ISAC-first, and 32% in SPT-first cohort (p = 0.016). For food allergens 13 and 12% additional sensitizations were detected by the microarray not detected by SPT in the two groups (p = 0.800). No additional food allergen was found by SPT in the ISAC-first group, while in 6% of the cases in the SPT-first group detected sensitizations were negative in the microarray. DISCUSSION: The ISAC-first approach followed by (fewer) SPTs meets the demands for a patient's tailored diagnostic work-up and therefore can be considered equivalent to the conventional way using the skin prick test as first screening tool, followed by IgE diagnosis. CONCLUSIONS: For the diagnostic verification of clinically suspected allergy, the novel concept "from molecules to clinic" offers a reliable diagnostic workup in shorter time. Due to lower skin test numbers it is especially applicable for young children and seniors, in atopic patients, and whenever skin tests get difficult or unreliable.

Allergen immunotherapy in people, dogs, cats and horses - differences, similarities and research needs.

In human patients with seasonal allergic rhinoconjunctivitis sensitized to grass pollen, the first successful allergen immunotherapy (AIT) was reported in 1911. Today, immunotherapy is an accepted treatment for allergic asthma, allergic rhinitis and hypersensitivities to insect venom. AIT is also used for atopic dermatitis and recently for food allergy. Subcutaneous, epicutaneous, intralymphatic, oral and sublingual protocols of AIT exist. In animals, most data are available in dogs where subcutaneous AIT is an accepted treatment for atopic dermatitis. Initiating a regulatory response and a production of "blocking" IgG antibodies with AIT are similar mechanisms in human beings and dogs with allergic diseases. Although subcutaneous immunotherapy is used for atopic dermatitis in cats, data for its efficacy are sparse. There is some evidence for successful treatment of feline asthma with AIT. In horses, most studies evaluate the effect of AIT on insect hypersensitivity with conflicting results although promising pilot studies have demonstrated the prophylaxis of insect hypersensitivity with recombinant antigens of biting midges (Culicoides spp.). Optimizing AIT using allergoids, peptide immunotherapy, recombinant allergens and new adjuvants with the different administration types of allergen extracts will further improve compliance and efficacy of this proven treatment modality.

Preclinical In Vitro and In Vivo Evaluation of [18F]FE@SUPPY for Cancer PET Imaging: Limitations of a Xenograft Model for Colorectal Cancer.

Molecular imaging probes such as PET-tracers have the potential to improve the accuracy of tumor characterization by directly visualizing the biochemical situation. Thus, molecular changes can be detected early before morphological manifestation. The A3 adenosine receptor (A3AR) is described to be highly expressed in colon cancer cell lines and human colorectal cancer (CRC), suggesting this receptor as a tumor marker. The aim of this preclinical study was the evaluation of [18F]FE@SUPPY as a PET-tracer for CRC using in vitro imaging and in vivo PET imaging. First, affinity and selectivity of FE@SUPPY and its metabolites were determined, proving the favorable binding profile of FE@SUPPY. The human adenocarcinoma cell line HT-29 was characterized regarding its hA3AR expression and was subsequently chosen as tumor graft. Promising results regarding the potential of [18F]FE@SUPPY as a PET-tracer for CRC imaging were obtained by autoradiography as ≥2.3-fold higher accumulation of [18F]FE@SUPPY was found in CRC tissue compared to adjacent healthy colon tissue from the same patient. Nevertheless, first in vivo studies using HT-29 xenografts showed insufficient tumor uptake due to (1) poor conservation of target expression in xenografts and (2) unfavorable pharmacokinetics of [18F]FE@SUPPY in mice. We therefore conclude that HT-29 xenografts are not adequate to visualize hA3ARs using [18F]FE@SUPPY.

Clinical reactivity of celery cultivars in allergic patients: Role of Api g 1.

BACKGROUND: Celery (Apium graveolens L.) is a vegetable consumed world-wide. Celery stalks and celeriac roots are often ingredients in convenient food products like spice blends and soups. OBJECTIVE: In this study, we examined the allergenicity of distinct celeriac cultivars. METHODS: Sixteen celery-allergic patients were identified using a double-blind, placebo-controlled food challenge. Ten different celeriac cultivars were used for skin prick testing in the patients. Two cultivars were further applied for oral food challenges; their protein composition was analysed by immunoblotting, and contents of major allergen Api g 1 were quantified. RESULTS: From the 10 investigated celeriac cultivars, two cultivars elicited significantly different skin reactivity ("Anita": 5.0 [2.0-12.0] mm vs "Prinz": 7.0 [3.0-9.5] mm; P = .047). Moreover, "Anita" induced fewer symptoms after a controlled oral-celeriac challenge in 14 patient (P < .001). The protein profiles on 2DE protein gels showed distinct protein patterns and higher protein amounts of Api g 1 in "Prinz" than in "Anita." CONCLUSIONS AND CLINICAL RELEVANCE: Taken together, the data from this study suggest that cultivar Anita is better tolerated in celery-allergic patients than "Prinz." Differences in the protein expression profile between the cultivars, particularly the different content of Api g 1, could cause the different allergenicity.

Molecular allergen profiling in horses by microarray reveals Fag e 2 from buckwheat as a frequent sensitizer.

BACKGROUND: Companion animals are also affected by IgE-mediated allergies, but the eliciting molecules are largely unknown. We aimed at refining an allergen microarray to explore sensitization in horses and compare it to the human IgE reactivity profiles. METHODS: Custom-designed allergen microarray was produced on the basis of the ImmunoCAP ISAC technology containing 131 allergens. Sera from 51 horses derived from Europe or Japan were tested for specific IgE reactivity. The included horse patients were diagnosed for eczema due to insect bite hypersensitivity, chronic coughing, recurrent airway obstruction and urticaria or were clinically asymptomatic. RESULTS: Horses showed individual IgE-binding patterns irrespective of their health status, indicating sensitization. In contrast to European and Japanese human sensitization patterns, frequently recognized allergens were Aln g 1 from alder and Cyn d 1 from Bermuda grass, likely due to specific respiratory exposure around paddocks and near the ground. The most prevalent allergen for 72.5% of the tested horses (37/51) was the 2S-albumin Fag e 2 from buckwheat, which recently gained importance not only in human but also in horse diet. CONCLUSION: In line with the One Health concept, covering human health, animal health and environmental health, allergen microarrays provide novel information on the allergen sensitization patterns of the companion animals around us, which may form a basis for allergen-specific preventive and therapeutic concepts.

AllergoOncology: Opposite outcomes of immune tolerance in allergy and cancer.

While desired for the cure of allergy, regulatory immune cell subsets and nonclassical Th2-biased inflammatory mediators in the tumour microenvironment can contribute to immune suppression and escape of tumours from immunological detection and clearance. A key aim in the cancer field is therefore to design interventions that can break immunological tolerance and halt cancer progression, whereas on the contrary allergen immunotherapy exactly aims to induce tolerance. In this position paper, we review insights on immune tolerance derived from allergy and from cancer inflammation, focusing on what is known about the roles of key immune cells and mediators. We propose that research in the field of AllergoOncology that aims to delineate these immunological mechanisms with juxtaposed clinical consequences in allergy and cancer may point to novel avenues for therapeutic interventions that stand to benefit both disciplines.

Debates in allergy medicine: Molecular allergy diagnosis with ISAC will replace screenings by skin prick test in the future.

In today's clinical practice patients' skin is used as screening organ for diagnosing type 1 allergy. According to European guidelines skin prick testing with a panel of 18 allergen extracts is recommended, in the US between 10 to 50 allergens are used. The specificity and sensitivity of skin testing is individually highly variable depending on age, body mass, and skin barrier status. In atopic inflammation skin testing gives more false positive results. Smaller skin area and strain limits prick testing in small children. Although the risk for systemic reactions in skin prick testing is very small, emergency medications must be available. Considering the fact that IgE is the only reliable biomarker for type I allergy, upfront IgE screening with ISAC, followed by fewer skin tests to approve positive sensitizations, is proposed. It is time to arrive in the age of molecular allergy diagnosis in daily patient care.

Spontaneous food allergy in Was-/- mice occurs independent of FcεRI-mediated mast cell activation.

BACKGROUND: Food allergies are a growing health problem, and the development of therapies that prevent disease onset is limited by the lack of adjuvant-free experimental animal models. We compared allergic sensitization in patients with food allergy or Wiskott-Aldrich syndrome (WAS) and defined whether spontaneous disease in Was-/- mice recapitulates the pathology of a conventional disease model and/or human food allergy. METHODS: Comparative ImmunoCAP ISAC microarray was performed in patients with food allergy or WAS. Spontaneous food allergy in Was-/- mice was compared to an adjuvant-based model in wild-type mice (WT-OVA/alum). Intestinal and systemic anaphylaxis was assessed, and the role of the high-affinity IgE Fc receptor (FcεRI) in allergic sensitization was evaluated using Was-/- Fcer1a-/- mice. RESULTS: Polysensitization to food was detected in both WAS and food-allergic patients which was recapitulated in the Was-/- model. Oral administration of ovalbumin (OVA) in Was-/- mice induced low titers of OVA-specific IgE compared to the WT-OVA/alum model. Irrespectively, 79% of Was-/- mice developed allergic diarrhea following oral OVA challenge. Systemic anaphylaxis occurred in Was-/- mice (95%) with a mortality rate >50%. Spontaneous sensitization and intestinal allergy occurred independent of FcεRI expression on mast cells (MCs) and basophils. CONCLUSIONS: Was-/- mice provide a model of food allergy with the advantage of mimicking polysensitization and low food-antigen IgE titers as observed in humans with clinical food allergy. This model will facilitate studies on aberrant immune responses during spontaneous disease development. Our results imply that therapeutic targeting of the IgE/FcεRI activation cascade will not affect sensitization to food.

Comparing immediate-type food allergy in humans and companion animals-revealing unmet needs.

Adverse food reactions occur in human as well as veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in both. In this position paper, we summarize the current knowledge on immediate-type food allergy vs other food adverse reactions in companion animals, and compare this to the human situation. While the prevalence of food allergy in humans has been well studied for some allergens, this remains to be investigated for animal patients, where owner-reported as well as veterinarian-diagnosed food adverse reactions are on the increase. The characteristics of the disease in humans vs dogs, cats, and horses are most often caused by similar, but sometimes species-dependent different pathophysiological mechanisms, prompting the specific clinical symptoms, diagnoses, and treatments. Furthermore, little is known about the allergen molecules causative for type I food allergy in animals, which, like in human patients, could represent predictive biomarkers for risk evaluation. The definite diagnosis of food allergy relies-as in humans-on elimination diet and provocation tests. Besides allergen avoidance in daily practice, novel treatment options and tolerization strategies are underway. Taken together, numerous knowledge gaps were identified in veterinary food allergy, which need to be filled by systematic comparative studies.

Biomarkers for monitoring clinical efficacy of allergen immunotherapy for allergic rhinoconjunctivitis and allergic asthma: an EAACI Position Paper.

BACKGROUND: Allergen immunotherapy (AIT) is an effective treatment for allergic rhinoconjunctivitis (AR) with or without asthma. It is important to note that due to the complex interaction between patient, allergy triggers, symptomatology and vaccines used for AIT, some patients do not respond optimally to the treatment. Furthermore, there are no validated or generally accepted candidate biomarkers that are predictive of the clinical response to AIT. Clinical management of patients receiving AIT and efficacy in randomised controlled trials for drug development could be enhanced by predictive biomarkers. METHOD: The EAACI taskforce reviewed all candidate biomarkers used in clinical trials of AR patients with/without asthma in a literature review. Biomarkers were grouped into seven domains: (i) IgE (total IgE, specific IgE and sIgE/Total IgE ratio), (ii) IgG-subclasses (sIgG1, sIgG4 including SIgE/IgG4 ratio), (iii) Serum inhibitory activity for IgE (IgE-FAB and IgE-BF), (iv) Basophil activation, (v) Cytokines and Chemokines, (vi) Cellular markers (T regulatory cells, B regulatory cells and dendritic cells) and (vii) In vivo biomarkers (including provocation tests?). RESULTS: All biomarkers were reviewed in the light of their potential advantages as well as their respective drawbacks. Unmet needs and specific recommendations on all seven domains were addressed. CONCLUSIONS: It is recommended to explore the use of allergen-specific IgG4 as a biomarker for compliance. sIgE/tIgE and IgE-FAB are considered as potential surrogate candidate biomarkers. Cytokine/chemokines and cellular reponses provided insight into the mechanisms of AIT. More studies for confirmation and interpretation of the possible association with the clinical response to AIT are needed.

AllergoOncology - the impact of allergy in oncology: EAACI position paper.

Th2 immunity and allergic immune surveillance play critical roles in host responses to pathogens, parasites and allergens. Numerous studies have reported significant links between Th2 responses and cancer, including insights into the functions of IgE antibodies and associated effector cells in both antitumour immune surveillance and therapy. The interdisciplinary field of AllergoOncology was given Task Force status by the European Academy of Allergy and Clinical Immunology in 2014. Affiliated expert groups focus on the interface between allergic responses and cancer, applied to immune surveillance, immunomodulation and the functions of IgE-mediated immune responses against cancer, to derive novel insights into more effective treatments. Coincident with rapid expansion in clinical application of cancer immunotherapies, here we review the current state-of-the-art and future translational opportunities, as well as challenges in this relatively new field. Recent developments include improved understanding of Th2 antibodies, intratumoral innate allergy effector cells and mediators, IgE-mediated tumour antigen cross-presentation by dendritic cells, as well as immunotherapeutic strategies such as vaccines and recombinant antibodies, and finally, the management of allergy in daily clinical oncology. Shedding light on the crosstalk between allergic response and cancer is paving the way for new avenues of treatment.

Allergens in veterinary medicine.

Allergic diseases in animals are increasingly gaining importance in veterinary practice and as research models. For intradermal testing and allergen immunotherapy, a good knowledge of relevant allergens for the individual species is of great importance. Currently, the knowledge about relevant veterinary allergens is based on sensitization rates identified by intradermal testing or serum testing for allergen-specific IgE; crude extracts are the basis for most evaluations. Only a few studies provide evidence about the molecular structure of (particularly) dust mite, insect and mould allergens in dogs and horses, respectively. In those species, some major allergens differ from those in humans. This position paper summarizes the current knowledge about relevant allergens in dogs, cats and horses.

Structural similarities of human and mammalian lipocalins, and their function in innate immunity and allergy.

Owners and their domestic animals via skin shedding and secretions, mutually exchange microbiomes, potential pathogens and innate immune molecules. Among the latter especially lipocalins are multifaceted: they may have an immunomodulatory function and, furthermore, they represent one of the most important animal allergen families. The amino acid identities, as well as their structures by superposition modeling were compared among human lipocalins, hLCN1 and hLCN2, and most important animal lipocalin allergens, such as Can f 1, Can f 2 and Can f 4 from dog, Fel d 4 from cats, Bos d 5 from cow's milk, Equ c 1 from horses, and Mus m 1 from mice, all of them representing major allergens. The ß-barrel fold with a central molecular pocket is similar among human and animal lipocalins. Thereby, lipocalins are able to transport a variety of biological ligands in their highly conserved calyx-like cavity, among them siderophores with the strongest known capability to complex iron (Fe(3+) ). Levels of human lipocalins are elevated in nonallergic inflammation and cancer, associated with innate immunoregulatory functions that critically depend on ligand load. Accordingly, deficient loading of lipocalin allergens establishes their capacity to induce Th2 hypersensitivity. Our similarity analysis of human and mammalian lipocalins highlights their function in innate immunity and allergy.

Impact of glutathione on the allergenicity of the peach lipid transfer protein Pru p 3.

BACKGROUND AND OBJECTIVE: The allergenic potential of proteins can be altered under various physicochemical conditions. Glutathione (GSH) is a reducing agent that is used as an antioxidant in food products. We aimed to characterize the natural folding of peach proteins and test the allergenicity of reduced and natural Pru p 3, the major peach allergen. METHODS: Pru p 3 was purified from peach, and its conformation was analyzed by means of circular dichroism. Using a thiol fluorescent probe, reduced proteins were detected in fresh peach. GSH-reduced Pru p 3 was tested in vitro for T-cell proliferation and in vivo using skin prick testing. RESULTS: GSH-reduced Pru p 3 produced variable skin prick reactions in peach-allergic patients. The proliferative response of peripheral blood mononuclear cells from allergic patients to reduced Pru p 3 tended to be less intense, whereas secretion of the cytokines IFN-γ, IL-5, and IL-10 was comparable. In a pool of sera from peach-allergic patients, reduction hardly impaired IgE-binding. Moreover, the stability of reduced Pru p 3 to gastrointestinal digestion was similar to that of the natural form. CONCLUSIONS: GSH can at least transiently reduce Pru p 3. We found that the effect of reduction on the allergenicity of Pru p 3 varied. Therefore, as an additive, GSH does not seem to eliminate the risk of reactions for peach-allergic patients.