IgE Reactivity Research Articles

Design of an Ara h 2 hypoallergen from conformational epitopes.

Adverse reactions are relatively common during peanut oral immunotherapy. To reduce the risk to the patient, some researchers have proposed modifying the allergen to reduce IgE reactivity, creating a putative hypoallergen. Analysis of recently cloned human IgG from patients treated with peanut immunotherapysuggested that there are three common conformational epitopes for the major peanut allergen Ara h 2. We sought to test if structural information on these epitopes could indicate mutagenesis targets for designing a hypoallergen and evaluated the reduction in IgE binding via immunochemistry and a mouse model of passive cutaneous anaphylaxis (PCA). X-ray crystallography characterized the conformational epitopes in detail, followed by mutational analysis of key residues to modify monoclonal antibody (mAb) and serum IgE binding, assessed by ELISA and biolayer interferometry. A designed Ara h 2 hypoallergen was tested for reduced vascularization in mouse PCA experiments using pooled peanut allergic patient serum. A ternary crystal structure of Ara h 2 in complex with patient antibodies 13T1 and 13T5 was determined. Site-specific mutants were designed that reduced 13T1, 13T5, and 22S1 mAbs binding by orders of magnitude. By combining designed mutations from the three major conformational bins, a hexamutant (Ara h 2 E46R, E89R, E97R, E114R, Q146A, R147E) was created that reduced IgE binding in serum from allergic patients. Further, in the PCA model where mice were primed with peanut allergic patient serum, reactivity upon allergen challenge was significantly decreased using the hexamutant. These studies demonstrate that prior knowledge of common conformational epitopes can be used to engineer reduced IgE reactivity, an important first step in hypoallergen design.

Clinical characteristics, allergic response to autologous semen, and desensitization in patients with postorgasmic illness syndrome.

Postorgasmic illness syndrome (POIS) is rare and includes a cluster of physical and cognitive symptoms that occur after ejaculation. The pathogenesis and effective treatments remain unclear. This study aimed to characterize the symptomatology of POIS, study the allergic response of autologous semen in patients and controls, and evaluate the effects of desensitization therapy. The clinical characteristics of 24 Chinese patients with POIS were analyzed. Skin prick tests, intracutaneous tests, and specific IgE detection were performed with autologous semen. Five patients were desensitized via subcutaneous injections of autologous semen. Evaluated outcomes included the clinical features of POIS; scores of the Self-rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), and visual analog scale (VAS) of symptoms; skin reactions; desensitization with diluted autologous seminal fluid; and the IgE reactivity patterns of immunoblotting and enzyme-linked immunosorbent assay in vitro. The most common symptom cluster was the general cluster, and the most prevalent symptoms were extreme fatigue and inattention. A total of 66.67% (14/21) of the patients had no symptoms or milder symptoms after nocturnal emission than after intercourse or masturbation. Of the patients, 87.5% (21/24) had psychiatric symptoms and 53.85% (7/13) had abnormal sex hormone levels. The SAS and SDS scores of the high and low VAS groups were significantly higher than those of the control group. Pearson analysis showed that the correlation coefficient between the SAS and VAS was 0.607 (P < .01) and that between the SDS and VAS was 0.490 (P < .05). The patients and healthy donors all had positive intracutaneous test results with their own semen, negative skin prick test results, and no IgE specific to autologous semen. Most patients (4/5) did not achieve ideal therapeutic effects with desensitization. Allergy is not the main pathogenesis of POIS, and desensitization with autologous semen is not effective for most patients. This project included the largest number of patients with POIS in China and assessed the allergic response to autologous semen and the effect of desensitization therapy. There is no objective method for evaluating the efficacy of desensitization with autologous semen. IgE-mediated semen allergy is not the main pathogenesis of POIS, and there is a positive chance that POIS is related to psychological factors. Most patients do not respond to desensitization with autologous semen, and POIS treatment should be individualized, especially in cases with uncertain causes.

Identification of Pla a 7 as a novel pollen allergen group in Platanus acerifolia pollen

BackgroundPlatanus acerifolia is recognized as a source of allergenic pollen worldwide. Currently, five Platanus acerifolia pollen allergens belonging to different protein families have been identified, in which profilin and enolase were characterized by our group recently. Besides, we also screened and identified a novel allergen candidate as triosephosphate isomerase, which was different from already known types of pollen allergens. However, the role of this novel allergen group in Platanus acerifolia pollen allergy was unclear. Therefore, we further investigated the allergenicity and clarify its clinical relevance in this study. MethodsThe natural triosephosphate isomerase from Platanus acerifolia pollen was purified by three steps of chromatography and identified by mass spectrometry. The cDNA sequence of this protein was matched from in-house transcripts based on internal peptide sequences, which was further confirmed by PCR cloning. The recombinant triosephosphate isomerase was expressed and purified from E. coli. Allergenicity analysis of this protein was carried out by enzyme linked immunosorbent assay, immunoblot, and basophil activation test. ResultsA novel allergen group belonging to triosephosphate isomerase was firstly identified in Platanus acerifolia pollen and named as Pla a 7. The cDNA of Pla a 7 contained an open reading frame of 762 bp encoding 253 amino acids. The natural Pla a 7 displayed 41.4% IgE reactivity with the patients’ sera by ELISA, in which the absorbance value showed correlation to the serum sIgE against Platanus acerifolia pollen extract. Inhibition of IgE-binding to pollen extracts reached 26%-94% in different Pla a 7-positive sera. The recombinant Pla a 7 exhibited weaker IgE-reactivity in ELISA than its natural form, but showed comparable activity in immunoblot. The allergenicity was further confirmed by basophil activation test. ConclusionsTriosephosphate isomerase (Pla a 7) was first recognized as pollen allergen in Platanus acerifolia pollen, which is a completely different type of pollen allergen from those previously reported. This finding is essential to enrich information on allergen components and pave the way for molecular diagnosis or treatment strategies for Platanus acerifolia pollen allergy.

Multi-omics analysis of zebrafish response to tick saliva reveals biological processes associated with alpha-Gal syndrome

The alpha-Gal syndrome (AGS) is a tick-borne allergy. A multi-omics approach was used to determine the effect of tick saliva and mammalian meat consumption on zebrafish gut transcriptome and proteome. Bioinformatics analysis using R software was focused on significant biological and metabolic pathway changes associated with AGS. Ortholog mapping identified highly concordant human ortholog genes for the detection of disease-enriched pathways. Tick saliva treatment increased zebrafish mortality, incidence of hemorrhagic type allergic reactions and changes in behavior and feeding patterns. Transcriptomics analysis showed downregulation of biological and metabolic pathways correlated with anti-alpha-Gal IgE and allergic reactions to tick saliva affecting blood circulation, cardiac and vascular smooth muscle contraction, behavior and sensory perception. Disease enrichment analysis revealed downregulated orthologous genes associated with human disorders affecting nervous, musculoskeletal, and cardiovascular systems. Proteomics analysis revealed suppression of pathways associated with immune system production of reactive oxygen species and cardiac muscle contraction. Underrepresented proteins were mainly linked to nervous and metabolic human disorders. Multi-omics data revealed inhibition of pathways associated with adrenergic signaling in cardiomyocytes, and heart and muscle contraction. Results identify tick saliva-related biological pathways supporting multisystemic organ involvement and linking α-Gal sensitization with other illnesses for the identification of potential disease biomarkers.

Penicillin allergy de-labelling by non-allergists: a comparison of testing protocols.

Optimizing penicillin allergy de-labelling (PADL) to ensure patients with an incorrect penicillin allergy record are de-labelled with minimal patient harm is important for antibiotic stewardship. The heterogeneity of inclusion and exclusion criteria in the published penicillin allergy testing protocols risks suboptimal delivery of PADL. We compared the similarities and the differences between non-allergist-delivered PADL testing protocols and make suggestions for harmonization. The observed variation in testing practice has two broad elements: (i) definitions and terminology; and (ii) differences in the acceptability of perceived risk. All direct drug provocation testing (DDPT) protocols included patients with benign delayed rash as eligible for testing, although the remoteness of the rash, and the terminology used to describe the rash, differed. Patients with features of potential IgE reactions were excluded from most DDPT protocols, but not all of them. There was differing advice on how to manage patients who had subsequently tolerated penicillin since the index reaction and differences in which patients were considered ineligible for DDPT due to acuity of illness, comorbidities and concomitant medications. Standardization of the terminology used in penicillin allergy testing protocols and consensus on inclusion and exclusion criteria are required for safe and efficient PADL delivery at scale by non-allergists.

Identification of S-adenosyl-l-homocysteine hydrolase from banana fruit as a novel plant panallergen

Banana allergy is often associated with the pollen and latex allergies, which led us to the hypothesis that some yet unidentified banana allergen could provide a basis of the latex-pollen-fruit syndrome. S-adenosyl-l-homocysteine hydrolase (SAHH) was recently identified in the literature as a novel plant allergen. This study aimed to assess the allergenic potential of the naturally occurring banana SAHH (nSAHH) and its recombinant homolog produced in E. coli (rSAHH). nSAHH showed IgE reactivity with a serum pool of twelve banana-allergic persons, while rSAHH displayed IgE reactivity in ten out of the twelve tested patients. Five linear B-cell epitopes were identified on the rSAHH surface, exhibiting ≥ 90 % sequence homology with relevant plant SAHH allergens. Our findings have elucidated SAHH as a novel plant panallergen, underlying the cross-reactivity between plant-derived food and respiratory allergens, confirming our initial hypothesis.

Serum Allergen-Specific Immunoglobulin E in Cats with Inflammatory Bronchial Disease.

The etiology of feline inflammatory bronchial disease is poorly understood. This study compares the degree of allergen-specific serum IgE responses between cats with feline asthma, chronic bronchitis, mixed inflammation, and clinically healthy cats (HCs). The retrospective case-control study used serum from eighteen cats with eosinophilic inflammation (EI), ten with neutrophilic inflammation (NI), six with mixed inflammation (MI), and fourteen HCs. Affected cats were categorized into groups based on bronchoalveolar lavage cytology. The measurement of IgE for 34 different allergens including fungal organisms, weeds, grasses, trees, mites, and insects was performed using an indirect ELISA. Positive reactions to allergens were detected in the serum of 17/18 cats with EI, 8/10 with NI, 6/6 with MI, and 11/14 HCs (p = 0.364). When overall positive reactions were compared between groups, cats with MI (p = <0.01) had significantly more positive reactions against mite allergens than HCs. Blood eosinophils inversely correlated with the absolute amount of allergen-specific serum IgE expressed in ELISA absorbance units (EAs) (p = 0.014). Sensitization against dust mites seems to be more prevalent in cats with MI. However, positive IgE reactions can be observed in healthy and diseased cats, and, therefore, need to be interpreted in the light of clinical findings and environmental conditions of individual patients.

Horse allergy: Curly Horses can mediate immune tolerance.

American Bashkir Curly Horses are claimed to be hypoallergenic, but this has not been clinically proven. In the present study, the effect of exposure to Curly Horses was investigated in 141 patients allergic to horses by measuring their lung function and nasal patency during Curly Horse contact. Continuous contact with Curly Horses, including riding and brushing, decreased the allergic riders' reactivity as measured by FEV1, PEF, and PNIF. Subsequent visits (up to 40 or more hours of riding) further reduced reactivity to the Curly Horses. Allergic events to horses occurred only in 72 out of 1312 riding hours, mainly in the first ten riding hours.In 41 out of the 141 patients, it was further investigated whether repeated exposure to Curly Horses could induce tolerance to other horses. Patients in the tolerance induction study were tested annually for horse allergy using a nasal provocation test. The tolerance induction study showed that exposure to Curly Horses induced immune tolerance to other horses in 88% of patients who completed the study.To understand the mechanism causing hypoallergenicity, we performed IgE immunoblots to determine whether Curly Horse hairs contain IgE binding proteins. However, no differences in IgE reactivity were found between Curly and non-Curly Horses. Moreover, the immune tolerance induction study patients did not show decreased IgE reactivity to hairs from Curly or non-Curly Horses even though patients had developed tolerance. However, we did find increasing levels of anti-horse IgG antibodies in the study patients.Overall, our data strongly suggests that continuous exposure to Curly Horses can induce immune tolerance, rendering these patients non-reactive to horses. The reason for the reduced clinical allergenicity of Curly Horses remains unclear, but the data suggest that blocking IgG antibodies may be of importance for immune tolerance development.

B-059 Allergen-specific IgE Measurement for Peanut Ara h 2*

Abstract Background Legumes such as peanuts are a major source of food allergies among children and adults. Ingestion is the primary route of exposure, although inhalation may also trigger an allergic response in patients with known hypersensitivity. Allergic reactions to peanut can include atopic dermatitis, angioedema, vomiting, diarrhea, and anaphylaxis. Several allergenic peanut proteins have been identified and linked with variable severity of patient symptoms. Ara h 2 is one of the proteins uniquely associated with severe peanut allergy. In this study, we evaluate the analytical performance of the Ara h 2 allergen containing reagent for use in the IMMULITE® 2000 3gAllergy® Specific IgE assay. Methods Serum samples were collected from 13 patient samples with documented histories of tree nut or legume-related allergies. The samples were analyzed for specific IgE reactivity to a commercially available recombinant Ara h 2 (rAra h 2) using the IMMULITE 2000 3gAllergy Specific IgE assay (Siemens Healthcare Diagnostics Inc., Tarrytown, NY). Precision, linearity, limit of detection, and endogenous interference were assessed. Results Repeatability and within-lab precision at all levels tested were less than 10% over a 20-day study. Regression analysis was performed following linearity assessment and resulted in a slope 95% CI of 0.9251–1.0492 (range 0.3–24 kU/L). Limit of blank and limit of detection were 0.02 kU/L and 0.08 kU/L, respectively. Endogenous interference testing showed &amp;lt;10% difference when spiked with hemoglobin (1000 mg/dL), intralipid (3000 mg/dL), and unconjugated bilirubin (40 mg/dL). Conclusion rAra h 2 allergen containing reagent for use in the IMMULITE 2000 3gAllergy Specific IgE assay is sensitive and capable of quantitatively measuring IgE in patients with clinical history of nut allergy. *Assay under development. Not available for sale. Future availability cannot be guaranteed.

Removal of N-Terminal Peptide Impacts Structural Aspects of an IgE-Reactive Recombinant Der p 5

(1) Background: Modification of the structural elements of allergens is widely used in the field of allergies. The goal of the present research was to express, purify, and characterize the shortened recombinant group 5 allergen of Dermatophagoides pteronyssinus (rDer p 5). (2) Methods: rDer p 5 storage stability and aggregation capacity were explored through in silico analysis, dynamic light scattering (DLS), and SDS-PAGE. Serum IgE reactivity and cytokine amount were investigated in sera or cell culture supernatants through ELISA, MULTIPLEX®, and Western blot analysis using sera from sensitized humans from Brazil, Colombia, and Ecuador. (3) Results: Dimeric rDer p 5 was detected through native PAGE, and this result was confirmed by data from DLS. The protein was thermically stable, as it did not degrade at 4 °C for 21 days. The shortened rDer p 5 was classified as a major IgE allergen in Brazil and Colombia, but minor in Ecuador. IL-13, IL-10, IL-1β, and IL-6 were significantly elevated in the sera of rDer p 5-reactive patients. The same cytokines plus IL-5 were more secreted by human cells upon rDer p 5 stimulation. (4) Conclusions: N-terminal peptide deletion led to a higher rDer p 5 folding stability, which, even though dimeric, was an IgE-reactive protein. Therefore, rDer p 5 could be used for molecular diagnostic applications or as backbone for hypoallergen design.

Bile salts enhance the susceptibility of the peach allergenic lipid transfer protein, Pru p 3, to in vitro gastrointestinal proteolysis

Sensitisation to the lipid transfer protein Pru p 3 is associated with severe allergic reactions to peach, the proteins stability being thought to play a role in its allergenicity. Lipid binding increases susceptibility of Pru p 3 to digestion and so the impact of bile salts on the in vitro gastrointestinal digestibility of Pru p 3 was investigated and digestion products mapped by SDS-PAGE and mass spectrometry. Bile salts enhanced the digestibility of Pru p 3 resulting in an ensemble of around 100 peptides spanning the protein’s sequence which were linked by disulphide bonds into structures of ~ 5–6 kDa. IgE binding studies with a serum panel from peach allergic subjects showed digestion reduced, but did not abolish, the IgE reactivity of Pru p 3. These data show the importance of including bile salts in vitro digestion systems and emphasise the need to profile of digestion in a manner that allows identification of immunologically relevant disulphide-linked peptide aggregates.

Purification, Immunological Identification, and Characterization of the Novel Silkworm Pupae Allergen Bombyx mori Lipoprotein 3 (Bomb m 6).

Allergic reactions caused by silkworm pupae greatly limit their utilization, and studies suggest that silkworm pupae proteins of 25-30 kDa may be the principal allergens. To further understand these allergens, we attempted to purify a protein of about 30 kDa by ammonium sulfate salting, pH-graded precipitation, and ion-exchange chromatography. The protein was identified by mass spectrometry and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), western blot, enzyme-linked immunosorbent assays, circular dichroism, and fluorescence spectroscopy analyses. We identified the purified protein as Bombyx mori lipoprotein 3 (Bmlp3), which has high IgE reactivity and is a novel uncharacterized allergen that we named Bomb m 6 according to the WHO/IUIS Allergen Nomenclature Sub-Committee. This allergen is stable against heat, acids, bases, and digestion. In conclusion, we successfully purified and characterized a novel silkworm pupa allergen, which may inform the diagnosis and treatment of silkworm pupa allergies.

A Food Matrix Triggers a Similar Allergic Immune Response in BALB/c Mice Sensitized with Native, Denatured, and Digested Ovalbumin.

The search for an animal model to evaluate the allergenic potential of processed food products is still ongoing. Both the sensitization to ovalbumin (OVA) in different structural states and the allergic response triggered after intragastric or food challenges were assessed. BALB/c mice were sensitized intraperitoneally to OVA (50 µg) in different structural states (native OVA, N-OVA; denatured OVA, D-OVA; formaldehyde- and lysine-treated OVA, FK-OVA; denatured OVA-FK, OVA-DFK; peptides from pepsin digestion, Pep-OVA). Anti-OVA-specific IgE responses were evaluated using ELISA. Anaphylactic signs and mMCP-1 serum levels were evaluated after intragastric (2.0 mg/OVA) and food (0.41 mg/OVA) challenges. IgE reactivities to N-OVA and D-OVA were similar among groups (p > 0.05). After the challenges, all OVA-sensitized mice developed mild to severe anaphylactic signs (p < 0.05 vs. control). Mice sensitized to N-OVA and D-OVA had the highest mMCP-1 serum levels after challenges (p < 0.05 vs. control). Allergic responses were similar despite the different OVA doses used for the challenges. The N-OVA-sensitized murine model of egg allergy proposed in the present study holds the potential for evaluating the impact of food matrix composition and processing on the threshold of egg-allergic responses.

Identification of probable pectinesterase as a major allergen of pollen of the Asian white birch (Betula platyphylla) in northern China.

Pollen of the Asian white birch (Betula platyphylla) is a major source of allergens in spring in northern China, yet little research on its pollen allergens has been done so far. To analyze the B. platyphylla pollen allergen profile of patients from northern China and to identify the major pollen allergens in this patient cohort. Sera from 35 Chinese patients with birch pollinosis were collected for this study. The IgE-binding proteins in B. platyphylla pollen extract were analyzed by IgE immunoblots. A novel major allergen was purified by cation exchange chromatography and affinity chromatography. Its IgE reactivity was evaluated by ELISA. The protein was excised from a 2D electrophoresis gel and subjected to ESI-QUAD-TOF. In our study cohort, the prevalence of IgE specific for Bet v 1 was 68.8% (n = 22/32) as measured by ImmunoCAP. In immunoblots, two major bands at around 17 kDa and 70 kDa were detected by IgE from 68.5% (24/35) and 65.7% (23/35) of sera, respectively. The 17 kDa band was identified as Bet v 1 by a monoclonal antibody to Bet v 1 and inhibition experiments with recombinant Bet v 1. The 70 kDa band was a polymorphic glycoprotein and 7 isoforms were found. The protein was identified as probably pectinesterase with a molecular weight of 66 kDa and a PI of 5.7. A 66 kDa protein, probably belonging to pectinesterase family, was identified as a novel major allergen of B. platyphylla pollen in patients from northern China.

Patterns of aeroallergen sensitization in asthma patients identified by latent class analysis: A cross-sectional study in China.

This cross-sectional study aimed to identify latent sensitization profiles of asthma patients in mainland China, unveiling the association between regional differences and sensitization patterns. 1056 asthma participants from 10 medical centers divided into eastern and western cohorts were clustered into four individual sensitization patterns, respectively, by using an unsupervised statistical modeling method, latent class analysis (LCA), based on the levels of 12 aeroallergens specific IgE reactivities. Moreover, differences in clinical characteristics and environmental exposures were compared in different sensitization patterns. Four distinct sensitization patterns in the two cohorts were defined as follows, respectively. Eastern cohort: Class 1: "High weed pollen and house dust mites (HDMs) sensitization" (8.87%), Class 2: "HDMs dominated sensitization" (38.38%), Class 3: "High HDMs and animal dander sensitization" (6.95%), Class 4: "Low/no aeroallergen sensitization" (45.80%). Western cohort: Class 1: "High weed pollen sensitization" (26.14%), Class 2: "High multi-pollen sensitization" (15.02%), Class 3: "HDMs-dominated sensitization" (10.33%), Class 4: "Low/no aeroallergen sensitization" (48.51%). Of note, the significant statistical difference in age, asthma control test score (ACT) and comorbidities were observed within or between different sensitization patterns. Exposure factors in different sensitization patterns were pointed out. Asthmatic patients with distinct sensitization patterns were clustered and identified through the LCA method, disclosing the relationship between sensitization profiles of multiple aeroallergens and geographical differences, providing novel insights and potential strategies for atopic disease monitoring, management and prevention in clinical practice.

Bos d 13, A Novel Heat-Stable Beef Allergen.

Red meat, a staple food of Western diets, can also induce IgE-mediated allergic reactions. Yet, apart from the heat-labile protein serum albumin and the carbohydrate α-Gal, the molecules causing allergic reactions to red meat remain unknown. IgE reactivity profiles of beef-sensitized individuals are analyzed by IgE-immunoblotting with protein extracts from raw and cooked beef. Two IgE-reactive proteins are identified by peptide mass fingerprinting as myosinlight chain 1 (MYL1) and myosin light chain 3 (MYL3) in cooked beef extract and are designated Bos d 13 isoallergens. MYL1 and MYL3 are produced recombinantly in Escherichia coli. ELISAs proved their IgE reactivity and circular dichroism analysis showed that they represent folded molecules with remarkable thermal stability. In vitro gastrointestinal digestion experiments showed the higher stability of rMYL1 as compared to rMYL3. Exposure of a monolayer of Caco-2 cells to rMYL1 indicated that the molecule is able to cross intestinal epithelial cells without disturbing the integrity of the tight junctions, suggesting the sensitizing capacity of MYL1. MYLs are identified as novel heat-stable bovine meat allergens.

Evaluation of IgG/IgE-binding capacity and functional properties of enzymatic hydrolysis in skimmed cow milk system.

Cow's milk (CM) allergy is a common food allergy that seriously impacts the growth and development of infants and children. However, CM is an important source of nutrients, and few studies focus on the effects of enzymatic hydrolysis treatment on the whole skimmed CM system. In this study, the IgG/IgE-binding and functional properties of Alcalase-, Protamex-, and Flavourzyme-treated skimmed CM (AT, PT, and FT, respectively) were systematically evaluated. The results showed that the treatment groups were mainly composed of low molecular weight (MW) peptides (<3kDa), accounting for 94.85%-97.90%. Additionally, the IgG reactivity of these peptides was significantly lower (p<0.05) than those of higher MW peptides (10-30kDa and >30kDa). The IgE reactivity of FT with higher MW peptides was the lowest among these groups, with the OD value reaching 0.089. Moreover, the total amino acid content of hydrolysates of skimmed CM (HM) increased significantly (skimmed CM, 5.94µg/mL; AT, 123.70 µg/mL; PT: 136.20µg/mL; FT, 988.72µg/mL) compared to that in skimmed CM. A total of 10, 10, and 7 flavor compounds were increased in AT, PT, and FT, respectively. Furthermore, the solubility, foamability, and emulsifying ability of HM were significantly improved, being 2.17-fold, 1.52-fold, and 1.96-fold higher in PT than in skimmed CM. These results lay a theoretical foundation for the development of hypoallergenic dairy products.

IgE-Mediated Shellfish Allergy in Children.

Shellfish, including various species of mollusks (e.g., mussels, clams, and oysters) and crustaceans (e.g., shrimp, prawn, lobster, and crab), have been a keystone of healthy dietary recommendations due to their valuable protein content. In parallel with their consumption, allergic reactions related to shellfish may be increasing. Adverse reactions to shellfish are classified into different groups: (1) Immunological reactions, including IgE and non-IgE allergic reactions; (2) non-immunological reactions, including toxic reactions and food intolerance. The IgE-mediated reactions occur within about two hours after ingestion of the shellfish and range from urticaria, angioedema, nausea, and vomiting to respiratory signs and symptoms such as bronchospasm, laryngeal oedema, and anaphylaxis. The most common allergenic proteins involved in IgE-mediated allergic reactions to shellfish include tropomyosin, arginine kinase, myosin light chain, sarcoplasmic calcium-binding protein, troponin c, and triosephosphate isomerase. Over the past decades, the knowledge gained on the identification of the molecular features of different shellfish allergens improved the diagnosis and the potential design of allergen immunotherapy for shellfish allergy. Unfortunately, immunotherapeutic studies and some diagnostic tools are still restricted in a research context and need to be validated before being implemented into clinical practice. However, they seem promising for improving management strategies for shellfish allergy. In this review, epidemiology, pathogenesis, clinical features, diagnosis, and management of shellfish allergies in children are presented. The cross-reactivity among different forms of shellfish and immunotherapeutic approaches, including unmodified allergens, hypoallergens, peptide-based, and DNA-based vaccines, are also addressed.

Frequent IgE recognition of Blomia tropicalis allergen molecules in asthmatic children and young adults in equatorial Africa.

Asthma is not well investigated in equatorial Africa and little is known about the disease-associated allergen molecules recognized by IgE from patients in this area. The aim was to study the molecular IgE sensitization profile of asthmatic children and young adults in a semi-rural area (Lambaréné) of an equatorial African country (Gabon), to identify the most important allergen molecules associated with allergic asthma in equatorial Africa. Fifty-nine asthmatic patients, mainly children and few young adults, were studied by skin prick testing to Dermatophagoides pteronyssinus (Der p), D. farinae (Der f), cat, dog, cockroach, grass, Alternaria and peanut. Sera were obtained from a subset of 35 patients, 32 with positive and 3 with negative skin reaction to Der p and tested for IgE reactivity to 176 allergen molecules from different allergen sources by ImmunoCAP ISAC microarray technology and to seven recombinant Blomia tropicalis (Blo t) allergens by IgE dot blot assay. Thirty-three of the 59 patients (56%) were sensitized to Der p and 23 of them (39%) were also sensitized to other allergen sources, whereas 9 patients (15%) were only sensitized to allergen sources other than Der p. IgE serology analyses (n=35) showed high IgE-binding frequencies to the Blo t allergens Blo t 5 (43%), Blo t 21 (43%) and Blo t 2 (40%), whereas the Der p allergens rDer p 2, rDer p 21 and rDer p 5 (34%, 29% and 26%) were less frequently recognized. Only few patients showed IgE reactivity to allergens from other allergen sources, except to allergens containing carbohydrate determinants (CCDs) or to wasp venom allergens (i.e., antigen 5). Our results thus demonstrate that IgE sensitization to mite allergens is very prevalent in asthmatics in Equatorial Africa with B. tropicalis allergen molecules representing the most important ones associated with allergic asthma.

2023 TERMIS – AMERICAS Conference &amp; Exhibition Boston Marriott Copley Place April 11–14, 2023

2023 TERMIS – AMERICAS Conference &amp; Exhibition Boston Marriott Copley Place April 11–14, 2023