Allergenicity of carbohydrates and their role in anaphylactic events

Allergenic potency of various foods of mammalian origin in patients with α-Gal syndrome

BACKGROUND

The α-Gal syndrome (AGS) is an emerging allergy to mammalian food caused by IgE-mediated reactions to the carbohydrate galactose-α-1,3-galactose (α-Gal). Mammalian food sources contain α-Gal, but the amount differs. The objective of this study was to investigate the allergenic potency of various foods of mammalian origin among AGS patients.

METHODS

Twenty-six AGS patients were included. Food extracts from innards, lean meats, processed meat products, milk, and whey were analyzed. Immunoblot, ELISA, immunofluorescence, and basophil activation test were used to determine the α-Gal content, characterize IgE binding, and assess foods' allergenicity.

RESULTS

The determined amount of α-Gal, IgE reactivity to food extracts, and food extract potencies to activate patients' basophils correlated well with each other. Pork and beef kidney showed the highest allergenicity. Beef liver and bacon showed allergenicity comparable to that of lean meats. Game meat seemed to have a higher allergenic potency than meats from farm-raised animals. The processed meat products liver pâté and black pudding, despite lower α-Gal content, demonstrated moderate allergenicity. Milk showed the lowest allergenicity. IgE reactivity to food extracts was highly similar for all patients and strongly dominated by the α-Gal epitope.

CONCLUSIONS

The allergenic potency of mammalian meat depends on the origin of the meat, the different cuts, and type of processing, with innards posing the greatest risk to AGS patients. Even processed mammalian meat constitutes a risk. Dairy products show the lowest risk. This study highlights the importance of analyzing even more foods to improve the management of AGS.

Molecular Allergology and Component-Resolved Diagnosis in Current Clinical Practice

Specific immunoglobulin E immunodiagnostics is becoming a convenient way to identify allergic patients and their specific allergies. These results are comparable to skin testing and may be more accessible for some populations. Each allergen contains thousands of molecules but only a few of these molecules are allergenic to humans. Each allergen has a number of individual components-generally proteins-which have different characteristics that may impact the effects of sensitization. Identification of the specific component allows for differentiation of the true allergies and can help to determine the risk of a significant clinical response.

The α-Gal epitope - the cause of a global allergic disease

The galactose-α-1,3-galactose (α-Gal) epitope is the cause of a global allergic disease, the α-Gal syndrome (AGS). It is a severe form of allergy to food and products of mammalian origin where IgE against the mammalian carbohydrate, α-Gal, is the cause of the allergic reactions. Allergic reactions triggered by parenterally administered α-Gal sources appear immediately, but those triggered via the oral route appear with a latency of several hours. The α-Gal epitope is highly immunogenic to humans, apes and old-world monkeys, all of which produce anti-α-Gal antibodies of the IgM, IgA and IgG subclasses. Strong evidence suggests that in susceptible individuals, class switch to IgE occurs after several tick bites. In this review, we discuss the strong immunogenic role of the α-Gal epitope and its structural resemblance to the blood type B antigen. We emphasize the broad abundance of α-Gal in different foods and pharmaceuticals and the allergenicity of various α-Gal containing molecules. We give an overview of the association of tick bites with the development of AGS and describe innate and adaptive immune response to tick saliva that possibly leads to sensitization to α-Gal. We further discuss a currently favored hypothesis explaining the mechanisms of the delayed effector phase of the allergic reaction to α-Gal. We highlight AGS from a clinical point of view. We review the different clinical manifestations of the disease and the prevalence of sensitization to α-Gal and AGS. The usefulness of various diagnostic tests is discussed. Finally, we provide different aspects of the management of AGS. With climate change and global warming, the tick density is increasing, and their geographic range is expanding. Thus, more people will be affected by AGS which requires more knowledge of the disease.

Tick salivary glycans - a sugar-coated tick bite

Ticks are hematophagous arthropods that transmit disease-causing pathogens worldwide. Tick saliva deposited into the tick-bite site is composed of an array of immunomodulatory proteins that ensure successful feeding and pathogen transmission. These salivary proteins are often glycosylated, and glycosylation is potentially critical for the function of these proteins. Some salivary glycans are linked to the phenomenon of red meat allergy - an allergic response to red meat consumption in humans exposed to certain tick species. Tick salivary glycans are also invoked in the phenomenon of acquired tick resistance wherein non-natural host species exposed to tick bites develop an immune response that thwarts subsequent tick feeding. This review dwells on our current knowledge of these two phenomena, thematically linked by salivary glycans.

Incidence and associated factors of cetuximab-induced hypersensitivity infusion reactions in 1392 cancer patients treated in four French areas: a possible association with Lyme disease?

BACKGROUND

Previous studies have observed an increased incidence of Cetuximab-induced hypersensitivity infusion reactions (CI-IRs) in the southeastern states of the USA. Tick's bites were suspected of generating cross-reactions between cetuximab and alpha-gal. This study aims was to describe the incidence and associated risk factors of CI-IRs, in the French areas chosen according to their Lyme disease incidence.

PATIENTS AND METHODS

A retrospective chart review was conducted on patients that received cetuximab infusion from January 2010 to June 2019 in 4 French areas with different Lyme disease incidence rates.

RESULTS

Of 1392 patients, 117 (8.4%) experienced a CI-IR, including 68 severe (grade 3 or 4) reactions (4.9%). This CI-IR incidence was significantly higher in the Lyme disease high-risk area than in the other areas (13.2% versus 7.1%, 8.1% and 6.4%; P = 0.016). Sex (P = 0.53), premedication (P = 0.91), primary cancer location (P = 0.46) and chemotherapy regimen type (P = 0.78) had no impact on CI-IR incidence in the overall population. In the head and neck squamous cell carcinoma (HNSCC) patient subgroup, CI-IRs were significantly more frequent in the high-risk area (16.4% versus 6.7%, 7.1% and 7.0%; P = 0.0015).

CONCLUSION

This study suggests that patients treated in the French area with the highest incidence of Lyme disease are at a higher risk of CI-IRs.

Towards the prediction of non-peptidic epitopes

In-silico methods for the prediction of epitopes can support and improve workflows for vaccine design, antibody production, and disease therapy. So far, the scope of B cell and T cell epitope prediction has been directed exclusively towards peptidic antigens. Nevertheless, various non-peptidic molecular classes can be recognized by immune cells. These compounds have not been systematically studied yet, and prediction approaches are lacking. The ability to predict the epitope activity of non-peptidic compounds could have vast implications; for example, for immunogenic risk assessment of the vast number of drugs and other xenobiotics. Here we present the first general attempt to predict the epitope activity of non-peptidic compounds using the Immune Epitope Database (IEDB) as a source for positive samples. The molecules stored in the Chemical Entities of Biological Interest (ChEBI) database were chosen as background samples. The molecules were clustered into eight homogeneous molecular groups, and classifiers were built for each cluster with the aim of separating the epitopes from the background. Different molecular feature encoding schemes and machine learning models were compared against each other. For those models where a high performance could be achieved based on simple decision rules, the molecular features were then further investigated. Additionally, the findings were used to build a web server that allows for the immunogenic investigation of non-peptidic molecules (http://tools-staging.iedb.org/np_epitope_predictor). The prediction quality was tested with samples from independent evaluation datasets, and the implemented method received noteworthy Receiver Operating Characteristic-Area Under Curve (ROC-AUC) values, ranging from 0.69–0.96 depending on the molecule cluster.

Small molecules found in cosmetics, foodstuffs, dyes, and industrial materials, but also those produced by plants, bacteria, and animals can trigger strong reactions of the human immune system and can therefore be hazardous to health. In the present work, several thousand immune-reactive small molecules (so-called non-peptidic epitopes) were classified by molecular structure and studied with the aim of identifying specific parts of the molecules responsible for such immune responses. Using a machine-learning approach (random forests and neural networks), we identified some substructures that appear strikingly often in non-peptidic epitopes and which may be responsible for the hazardous immune response. Such knowledge may help to explain allergic reactions to chemicals and also to minimize the health risks of new chemicals in industrial production. To support this endeavor, we have implemented the method in a publicly available web application. This can be used for the prediction and identification of non-peptidic epitopes and their underlying substructures.

Epitope mapping and the effects of various factors on the immunoreactivity of main allergens in egg white

Egg white has high protein content and numerous biological/functional properties. However, reported allergenicity for some of the proteins in egg white is an issue that needs to be paid exclusive attention. A consideration of the structure of IgE epitopes and their sequences, as well as a comprehensive understanding of the effects of various processes on epitopes and the impact of the gastrointestinal tract on them, can help target such issues. The current study focuses on the identified IgE epitopes in egg white proteins and evaluation of the effects of the gastrointestinal digestion, carbohydrate moiety, food matrix, microbial fermentation, recombinant allergen, heat treatment, Maillard reaction and combination of various processes and gastrointestinal digestion on egg white allergenicity. Although the gastrointestinal tract reduces the immunoreactivity of native egg white proteins, some of the IgE epitope-containing fragments remain intact during the digestion process. It has been found that the gastrointestinal tract can have both positive and negative impacts on the IgE binding activities of egg white proteins. Elimination of the carbohydrate moiety leads to a reduction in the immunoreactivity of ovalbumin. But, such effects from the carbohydrate parts in the IgE binding activity need to be explored further. In addition, the interaction between the egg white proteins and the food matrix leads to various effects from the gastrointestinal tract on the digestion of egg white proteins and their subsequent immunoreactivity. Further on this matter, studies have shown that both microbial fermentation and Maillard reaction can reduce the IgE binding activities of egg white proteins. Also, as an alternate approach, the thermal process can be used to treat the egg white proteins, which may result in the reduction or increase in their IgE binding activities depending on the conditions used in the process. Overall, based on the reported data, the allergenicity levels of egg white proteins can be mitigated or escalated depending on the conditions applied in the processing of the food products containing egg white. So far, no practical solutions have been reported to eliminate such allergenicity.

The α-Gal Syndrome and Potential Mechanisms

The α-Gal syndrome is a complex allergic disease characterized by the development of specific IgE antibodies against the carbohydrate galactose-α-1,3-galactose (α-Gal), an oligosaccharide present in cells and tissues of non-primate mammals. Individuals with IgE antibodies to α-Gal suffer from a delayed form of anaphylaxis following red meat consumption. There are several features that make the α-Gal syndrome such a unique allergic disease and distinguish it from other food allergies: (1) symptoms causing IgE antibodies are directed against a carbohydrate moiety, (2) the unusual delay between the consumption of the food and the onset of the symptoms, and (3) the fact that primary sensitization to α-Gal occurs via tick bites. This review takes a closer look at the immune response against α-Gal, in healthy and in α-Gal allergic individuals. Furthermore, the similarities and differences between immune response against α-Gal and against the other important glycan moieties associated with allergies, namely cross-reactive carbohydrate determinants (CCDs), are discussed. Then different mechanisms are discussed that could contribute to the delayed onset of symptoms after consumption of mammalian meat. Moreover, our current knowledge on the role of tick bites in the sensitization process is summarized. The tick saliva has been shown to contain proteins carrying α-Gal, but also bioactive molecules, such as prostaglandin E2, which is capable of stimulating an increased expression of anti-inflammatory cytokines while promoting a decrease in the production of proinflammatory mediators. Together these components might promote Th2-related immunity and trigger a class switch to IgE antibodies directed against the oligosaccharide α-Gal. The review also points to open research questions that remain to be answered and proposes future research directions, which will help to get a better understanding and lead to a better management of the disease.

Are humanized IgE reporter systems potential game changers in serological diagnosis of human parasitic infection?

Immunoglobulin E (IgE) is thought to have evolved to protect mammalian hosts against parasitic infections or toxins and plays a central role in the pathogenesis, diagnosis, and therapy of IgE-mediated allergy. Despite the prominence of IgE responses in most parasitic infections, and in stark contrast to its use in the diagnosis of allergy, this isotype is almost completely unexploited for parasite diagnosis. Here, we discuss the perceived or real limitations of IgE-based diagnosis in parasitology and suggest that the recent creation of a new generation of very sensitive cellular IgE-based reporters may represent a powerful new diagnostic platform, but needs to be based on a very careful choice of diagnostic allergens.

ChAlPred: A web server for prediction of allergenicity of chemical compounds

BACKGROUND

Allergy is the abrupt reaction of the immune system that may occur after the exposure to allergens such as proteins, peptides, or chemicals. In the past, various methods have been generated for predicting allergenicity of proteins and peptides. In contrast, there is no method that can predict allergenic potential of chemicals. In this paper, we described a method ChAlPred developed for predicting chemical allergens as well as for designing chemical analogs with desired allergenicity.

METHOD

In this study, we have used 403 allergenic and 1074 non-allergenic chemical compounds obtained from IEDB database. The PaDEL software was used to compute the molecular descriptors of the chemical compounds to develop different prediction models. All the models were trained and tested on the 80% training data and evaluated on the 20% validation data using the 2D, 3D and FP descriptors.

RESULTS

In this study, we have developed different prediction models using several machine learning approaches. It was observed that the Random Forest based model developed using hybrid descriptors performed the best, and achieved the maximum accuracy of 83.39% and AUC of 0.93 on validation dataset. The fingerprint analysis of the dataset indicates that certain chemical fingerprints are more abundant in allergens that include PubChemFP129 and GraphFP1014. We have also predicted allergenicity potential of FDA-approved drugs using our best model and identified the drugs causing allergic symptoms (e.g., Cefuroxime, Spironolactone, Tioconazole). Our results agreed with allergenicity of these drugs reported in literature.

CONCLUSIONS

To aid the research community, we developed a smart-device compatible web server ChAlPred (https://webs.iiitd.edu.in/raghava/chalpred/) that allows to predict and design the chemicals with allergenic properties.

Hypersensitivity reactions to biologics (part I): allergy as an important differential diagnosis in complex immune-derived adverse events

Purpose

Biotechnological substances (BSs) are strongly relied upon to prevent rejection of transplanted organs, and to treat oncological, allergological, and other inflammatory diseases. Allergic reactions to partly foreign biologics can occur due to their potential immunogenicity. The severity of an immune response to a biological drug may range from no clinical significance to a severe, life-threatening anaphylactic reaction.

Methods

Detailed searches were performed on Pubmed, Web of Science, and Google Scholar to include all available publications. In addition, the Food and Drug Administration, the European Medicines Agency, and British Columbia Cancer Agency Drug Manual databases were screened for hypersensitivity reaction (HSR), infusion reaction, injection site reaction, urticaria, and anaphylaxis for individual BSs.

Results

Treatment with BSs can cause various types of HSR. These are mentioned in the literature with definitions such as allergic reactions, anaphylactoid reactions, anaphylaxis, HSR, infusion reactions, injection site reactions, cytokine release syndrome, and urticaria. Due to the overlap in signs and symptoms in the reported descriptions, it is not always possible to differentiate these reactions properly according to their pathomechanism. Similarly, many data reported as anaphylaxis actually describe severe anaphylactic reactions (grades III or IV).

Conclusion

There is an urgent need for a simpler symptom- or system-based classification and scoring system to create an awareness for HSRs to BSs. A better understanding of the pathophysiology of HSRs and increased clinical experience in the treatment of side effects will provide timely control of unexpected reactions. As a result, immunotherapy with BSs will become safer in the future.

Galactose-α-1,3-galactose (alpha-gal) allergy: first pediatric case in a series of patients in Spain

INTRODUCTION AND OBJECTIVES

Allergy to galactose-α-1,3-galactose (alpha-gal) is a peculiar form of food allergy generally manifesting as an anaphylactic reaction hours after mammalian meat consumption, due to the presence of specific IgE against this oligosaccharide. In addition, immediate anaphylaxis may develop after exposure to other sources of alpha-gal, such as monoclonal antibody cetuximab, vaccines, plasma expanders or anti-snake venoms. Sensitization to alpha-gal has also been implicated in the rapid degeneration of biological valve implants, and recognized as a cause of occupational disease in cattle raisers. The implication of tick bites in this type of sensitization has been accepted by all the research groups dedicated to this disease.

PATIENTS AND METHOD

The present study describes the clinical and sensitization characteristics of 39 patients diagnosed with alpha-gal allergy in the hospitals of our province (Lugo, Monforte de Lemos and Burela, Spain).

RESULTS

Most patients were middle-age males. Of note, is the fact that the series includes the first pediatric patient reported in Spain to date. The predominant clinical manifestations were urticaria or delayed anaphylaxis after consumption of mammalian meat. Seventy-four percent of the patients reported having suffered a previous tick bite, and the clinical presentation of anaphylaxis was significantly more prevalent in those with a persistent local reaction following the bite than in those with no such reaction (p = 0.032).

CONCLUSIONS

A review is also made of the disorder which, due to its variable clinical expression, is referred to as alpha-gal syndrome. The study concludes that a diagnosis of alpha-gal allergy should be considered in patients with urticaria-anaphylaxis of uncertain origin or manifesting after the administration of vaccines or products of bovine/porcine origin.

Only α-Gal bound to lipids, but not to proteins, is transported across enterocytes as an IgE-reactive molecule that can induce effector cell activation

BACKGROUND

The oligosaccharide galactose-α-1,3-galactose (α-Gal), present in mammalian proteins and lipids, causes an unusual delayed allergic reaction 3 to 6 hours after ingestion of mammalian meat in individuals with IgE antibodies against α-Gal. To better understand the delayed onset of allergic symptoms and investigate whether protein-bound or lipid-bound α-Gal causes these symptoms, we analyzed the capacity of α-Gal conjugated proteins and lipids to cross a monolayer of intestinal cells.

METHODS

Extracts of proteins and lipids from beef were prepared, subjected to in vitro digestions, and added to Caco-2 cells grown on permeable supports. The presence of α-Gal in the basolateral medium was investigated by immunoblotting, thin-layer chromatography with immunostaining and ELISA, and its allergenic activity was analyzed in a basophil activation test.

RESULTS

After addition of beef proteins to the apical side of Caco-2 cells, α-Gal containing peptides were not detected in the basolateral medium. Those peptides that crossed the Caco-2 monolayer did not activate basophils from an α-Gal allergic patient. Instead, when Caco-2 cells were incubated with lipids extracted from beef, α-Gal was detected in the basolateral medium. Furthermore, these α-Gal lipids were able to activate the basophils of an α-Gal allergic patient in a dose-dependent manner.

CONCLUSION

Only α-Gal bound to lipids, but not to proteins, is able to cross the intestinal monolayer and trigger an allergic reaction. This suggests that the slower digestion and absorption of lipids might be responsible for the unusual delayed allergic reactions in α-Gal allergic patients and identifies glycolipids as potential allergenic molecules.

Preventing iatrogenic gelatin anaphylaxis

OBJECTIVE

To assess the iatrogenic risks of gelatin allergy and identify resources for patient management.

DATA SOURCES

A literature review was performed using PubMed and public databases provided by the National Library of Medicine.

STUDY SELECTIONS

Reports of iatrogenic gelatin allergy associated with vaccines, hemostatic agents, intravenous colloids, medicinal capsules, and intraoperative surgical supplies.

RESULTS

Gelatin ingredients may not be identified by electronic medical record safeguards, and an exhaustive listing of potential iatrogenic exposures is elusive. The National Library of Medicine AccessGUDID (https://accessgudid.nlm.nih.gov/) can be a useful resource in evaluating medical devices for gelatin content. Unexpected sources of iatrogenic gelatin exposure include hemostatic agents, vascular grafts, intravascular cannulas, bone replacement implants, and emergency resuscitation fluids.

CONCLUSION

Vigilance is important within medical systems to avoid inadvertent gelatin exposure when caring for patients with gelatin allergy. Additional safeguards are needed to remove latent health care system errors that fail to prevent gelatin administration in this at-risk population.

Diagnoses and Management of Drug Hypersensitivity and Anaphylaxis in Cancer and Chronic Inflammatory Diseases: Reactions to Taxanes and Monoclonal Antibodies

Due to the increase in utilization of chemotherapies and antibodies, drug hypersensitivity reactions have increased dramatically worldwide, preventing the use of first-line therapies and impacting patients' survival and quality of life. Some of the more frequently used medications in cancer include taxanes for ovarian, lung, breast, and prostate cancers. Monoclonal antibodies are used in the treatment of neoplastic, autoimmune, and inflammatory diseases, and their clinical applications are becoming broader. Monoclonal antibody targets include CD20, HER-2, EGFR, IL-6 receptor, TNF-α, CD30, VEGF-A, IgE, and more, and examples of immune-mediated and inflammatory diseases that respond to monoclonal antibodies include rheumatoid arthritis, Crohn's disease, ulcerative colitis, juvenile idiopathic arthritis, psoriasis and psoriatic arthritis, Wegener's granulomatosis, microscopic polyangiitis, ankylosing spondylitis, plaque psoriasis, and asthma. Neoplastic diseases include non-Hodgkin's lymphoma, chronic lymphocytic leukemia, and colorectal, breast, gastric, and lung cancer. The clinical presentation of drug hypersensitivity reactions ranges from mild cutaneous reactions to life-threatening symptoms including anaphylaxis. Rapid drug desensitization (RDD) has become a groundbreaking approach to the management of immediate drug hypersensitivity reactions IgE and non-IgE mediated. It is the only effective procedure that enables sensitized patients to receive the full treatment dose safely, thus representing an important advance in the patients' treatment and prognosis. The aim of this review is to provide an update on hypersensitivity reactions to commonly used monoclonal and taxanes, their clinical presentations, diagnosis, and the use of RDD for their management.

Allergic and intolerance reactions to wine

Hypersensitivity reactions to alcoholic beverages (particularly red wine) are relatively frequent, affecting 10% of the general population. Hypersensitivity reactions due to alcoholic drinks, mainly in the form of airway reactions (rhinitis and asthma), occur significantly more frequently in persons with pre-existing rhinitis and asthma. In terms of pathogenesis, it has to be differentiated between immunologic, mainly IgE-mediated, hypersensitivity reactions (wine allergies), and intolerance reactions in which no causative allergen-specific immune mechanisms can be detected. Allergens responsible for wine allergy could be: grape (Vitis vinifera) proteins (particularly the major allergen lipid transfer protein Vit v1), proteins and ingredients used for the fining of wines such as fish gelatin or isinglass (swim bladder of the fish huso, family of sturgeons), ovalbumin, dairy (casein) products, gum arabic, enzymes (lysozyme, pectinase, glucanase, cellulase, glucosidase, urease, aromatic enzymes), molds (particularly Botrytis cinerea) responsible for the noble rot in wines, yeasts and proteins from insects that contaminated the mash. Type 1 allergic reactions (positive prick tests) have been described for inorganic components like ethanol, acetaldehyde, acetic acid and sulfites, but no specific IgE could be detected in the serum. Ethanol, acetaldehyde and acetic acid, flavonoids (anthocyanins and chatechines), sulfites, histamine and other biogenic amines are the main causative agents of intolerance reactions (pseudoallergic reactions) to wine. After a short historic review of viticulture and the importance of wine in classical antiquity, we go into the chemical processes of alcoholic fermentation and the genetically inherited “flush syndrome” caused by an acetaldehyde dehydrogenase 2 polymorphism, subsequently we focus on the different etiologic factors of allergies and intolerance reactions to wine. The most frequent intolerance reactions to sulfites occur particularly after the ingestion of white wine and in asthma patients. Intolerance reactions to histamine and other biogenic amines occur mainly after ingestion of red wine and in persons with diamine oxidase (DAO) deficiency.

Under the superficial dichotomy pathogen and allergen are two manifestations of same immune activation and pathogenesis mechanisms

Pathogens and allergens are deemed as two contrasting facets of host immune status, deficiency and exuberant. In silico domain analysis of a diverse panel of pathogen and allergen proteins has revealed the shortcoming of this notion. Both the pathogen and allergen proteins elicit immune activation, with the outcome of immune agitation depending on the pathogen strain, allergen exposure duration, and host factors. Pathogens can replicate within the host and constantly irritate the immune system, leading to blood coagulation, respiratory collapse and death. Allergens, being non-viable, can only provoke the immune system transiently; however, depending on the allergen dose and extent exposed to, inflammation and fatality can occur. In silico analysis of pathogen and allergen proteins showed the conserved domains to be AAA, WR1, VKc, Kelch, Hr1, HAMP, HELICc, Dak2, CHAD, CHASE2, Galanin, PKS_TE, Robl_LC7, Excalibur, DISIN, etc. This exciting discovery can have far-reaching effects in drug target identification approaches.

Qualitative and Quantitative Analysis of Carbohydrate Modification on Glycoproteins from Seeds of Ginkgo biloba

Recent progress in the relationship between carbohydrate cross-reactive determinants (CCDs) and allergic response highlights the importance of carbohydrate moieties in the innate immune system. Previous research pointed out that the protein allergen in Ginkgo biloba seeds is glycosylated, and the oligosaccharides conjugated to these proteins might also contribute to the allergy. The aim of this study was to analyze carbohydrate moieties, especially N-linked glycans, of glycoproteins from Ginkgo seeds originating from different places for detailed structures, to enable further research on the role played by N-glycans in Ginkgo-caused allergy. Results of monosaccharide composition and immunoblotting assays indicated the existence of N-glycans. Detailed structural elucidation of the N-glycans was further carried out by means of hydrophilic interaction ultraperformance liquid chromatography (HILIC-UPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In total, 14 out of 16 structures detected by UPLC were confirmed by MALDI-TOF-MS and tandem mass spectrometry, among which complex-type N-glycans bearing Lewis A determinants and high-mannose-type N-glycans were identified from Ginkgo seeds for the first time. Precise quantification of N-glycans was performed by use of an external standard, and both the absolute amount of each N-glycan and the percentage of different types of N-glycan showed significant diversity among the samples without any pattern of geographic variation.

Accurate assessment of alpha-gal syndrome using cetuximab and bovine thyroglobulin-specific IgE

SCOPE

IgE against galactose-α-1,3-galactose (α-Gal) causes alpha-gal syndrome. Bovine thyroglobulin (BTG) and cetuximab share this epitope. We aimed to determine the utility of specific IgE (sIgE) against cetuximab as compared to BTG for diagnosing alpha-gal syndrome.

METHODS AND RESULTS

Twelve patients with alpha-gal syndrome, 11 patients with immediate beef or pork allergy, 18 asymptomatic individuals with meat sensitization, and 10 non-atopic subjects were enrolled. We checked the levels of sIgE against BTG and cetuximab using the streptavidin CAP assay. Additionally, IgE reactivity to BTG and cetuximab was assessed by immunoblotting. All alpha-gal syndrome patients had a high concentration of sIgE against BTG, and cetuximab. In contrast to alpha-gal syndrome, patients with immediate allergic reactions to meat consumption and those with asymptomatic sensitization had significantly lower concentration of BTG and cetuximab sIgE, and a high prevalence of sIgE against bovine or porcine serum albumin. Although the concentration of sIgE against alpha-gal was lower in individuals with asymptomatic sensitization, IgE immunoblotting showed the presence of sIgE against α-Gal in this group.

CONCLUSION

Differentiation of alpha-gal syndrome from patients with immediate allergy to meat consumption or asymptomatic sensitization requires quantification of cetuximab- or BTG-induced sIgE via detection of IgE for α-gal.

Outpatient Emergencies: Anaphylaxis

Anaphylactic fatalities are rare; however, mild reactions can rapidly progress to cardiovascular and respiratory arrest. The clinical course of anaphylaxis can be unpredictable. Prompt and early use of epinephrine should be considered. Most anaphylaxis episodes have an immunologic mechanism involving immunoglobulin E (IgE). Foods are the most common cause in children; medications and insect stings are more common in adults. When the cause is not completely avoidable or cannot be determined, a patient should be supplied with autoinjectable epinephrine and be instructed its use. They should keep the device with them at all times and taught the signs and symptoms of anaphylaxis.

Food Allergy: What We Know Now

Food allergy is an adverse immune reaction that occurs reproducibly on exposure to a given food. Prevalence rates of food allergy continue to increase worldwide, sparking continual research efforts in finding a suitable and safe cure. Food avoidance, the current standard of care, can be difficult to achieve. This review aims to provide a broad overview of immunoglobulin E-mediated food allergy, highlighting its epidemiology, masqueraders, immunopathophysiology, clinical presentation, diagnostic work-up and available preventative and treatment strategies. This review also discusses novel, investigative therapies that offer promising therapeutic options, yet require continued research efforts to determine safety effects. Inducing tolerance, whether by immunotherapy or by the administration of monoclonal antibodies, allows us to move toward a cure for food allergy, which could vastly change this field of allergic diseases in the coming decades.

Delayed immediate-type hypersensitivity to red meat and innards: current insights into a novel disease entity

The development of component-resolved diagnostics instead of whole extracts has brought about major advances in recent years. Particularly remarkable has been the identification of new disease entities based on the detection of IgE antibodies against specific individual components. In this context, delayed immediate-type hypersensitivity to red meat and innards plays a key role. This disorder is more common in German-speaking countries and likely still underdiagnosed. Affected individuals exhibit delayed type I reactions following the consumption of red meat or innards (responses to the latter are more rapid). All patients have IgE antibodies against the oligosaccharide galactose-α-1,3-galactose - alpha-gal. Those affected also have to avoid alpha-gal-containing drugs such as cetuximab or gelatin-containing colloidal solutions. Also referred to as alpha-gal syndrome, this condition is unique in that it is characterized by type I hypersensitivity to a sugar instead of a protein. Given that many patients have a history of recurrent episodes of acute urticaria or angioedema, dermatologists should be familiar with the alpha-gal syndrome.

Clinical spectrum of α-Gal syndrome: from immediate-type to delayed immediate-type reactions to mammalian innards and meat

The term α-Gal syndrome describes a novel IgE-mediated immediate-type allergy to the disaccharide galactose-α-1,3-galactose (α-Gal). Its classification as a syndrome is proposed on the basis of its clinical relevance in three different fields of allergy: food, drugs, and tick bites. The main focus of the present article is on α-Gal as an eliciting allergen in food allergy. It was recently shown that immediate-type allergies to pork kidney and other mammalian innards belong to the spectrum of α-Gal syndrome. These allergic reactions manifest as classic immediate-type allergies with a typical latency of under 1 h. The phenomenon of a delayed-onset immediate-type allergy with a latency of 3-6 h following ingestion of mammalian meat is considered pathognomonic for α-Gal syndrome. This clinically distinct type of presentation can be explained using the concept of food-dependent exercise-induced anaphylaxis (FDEIA). However, clinical observations and challenge testing in this constellation reveal that individual sensitivity in α-Gal patients is highly variable and which broadens our basic understanding of α-Gal syndrome.

Overview of food allergy diagnosis

Food allergy is a condition with significant social and economic impact and a topic of intense concern for scientists and clinicians alike. Worldwide, over 220 million people suffer from some form of food allergy, but the number reported is just the tip of the iceberg. Recent years have brought new perspectives in diagnosing food allergy. Elucidating incriminated immunological mechanisms, along with drawing the clinical phenotype of food hypersensitivity reactions ensures an accurate diagnosis of food allergy. Moreover, molecular based allergy diagnosis, which is increasingly used in routine care, is a stepping-stone to improved management of food allergy patients. The aim of this review is to summarize the topic of IgE-mediated food allergy from the perspective of current diagnostic methods.

IgE reactivity to carbohydrate moieties of glycoproteins in wheat allergy

Carbohydrate moieties of different glycoproteins, such as cross-reactive carbohydrate determinants (CCDs) and galactose α-1,3-galactose, can induce IgE reactivity with varied clinical significance. In this study, the possible participation of glycan from wheat gliadin, with respect to its IgE-binding capacity, was investigated in children with food allergies to wheat. Total IgE and wheat-specific IgE quantification, documentation of history, and/or oral food challenge (OFC) were performed for 52 children. Subjects with positive wheat-specific IgE were characterized as the symptomatic group, never-exposed group, or asymptomatic group. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and glycan detection in gliadin were performed. IgE binding to gliadin and deglycosylated gliadin was measured by immunoblotting and ELISA. Gliadin-specific IgE was detected and correlated with wheat-specific IgE in the symptomatic, never-exposed, and asymptomatic groups. The glycan range overlapped significantly with the gliadin range. Deglycosylation of gliadin reduced the allergenicity of gliadin. In gliadin, the allergenicity of the glycan portion was greater in the symptomatic group than in the never-exposed and asymptomatic groups. We conclude that N-glycan in gliadin might exhibit allergenicity as a possible carbohydrate epitope in wheat allergy in children.

The project data sphere initiative: accelerating cancer research by sharing data

BACKGROUND

In this paper, we provide background and context regarding the potential for a new data-sharing platform, the Project Data Sphere (PDS) initiative, funded by financial and in-kind contributions from the CEO Roundtable on Cancer, to transform cancer research and improve patient outcomes. Given the relatively modest decline in cancer death rates over the past several years, a new research paradigm is needed to accelerate therapeutic approaches for oncologic diseases. Phase III clinical trials generate large volumes of potentially usable information, often on hundreds of patients, including patients treated with standard of care therapies (i.e., controls). Both nationally and internationally, a variety of stakeholders have pursued data-sharing efforts to make individual patient-level clinical trial data available to the scientific research community.

POTENTIAL BENEFITS AND RISKS OF DATA SHARING

For researchers, shared data have the potential to foster a more collaborative environment, to answer research questions in a shorter time frame than traditional randomized control trials, to reduce duplication of effort, and to improve efficiency. For industry participants, use of trial data to answer additional clinical questions could increase research and development efficiency and guide future projects through validation of surrogate end points, development of prognostic or predictive models, selection of patients for phase II trials, stratification in phase III studies, and identification of patient subgroups for development of novel therapies. Data transparency also helps promote a public image of collaboration and altruism among industry participants. For patient participants, data sharing maximizes their contribution to public health and increases access to information that may be used to develop better treatments. Concerns about data-sharing efforts include protection of patient privacy and confidentiality. To alleviate these concerns, data sets are deidentified to maintain anonymity. To address industry concerns about protection of intellectual property and competitiveness, we illustrate several models for data sharing with varying levels of access to the data and varying relationships between trial sponsors and data access sponsors.

THE PROJECT DATA SPHERE INITIATIVE

PDS is an independent initiative of the CEO Roundtable on Cancer Life Sciences Consortium, built to voluntarily share, integrate, and analyze comparator arms of historical cancer clinical trial data sets to advance future cancer research. The aim is to provide a neutral, broad-access platform for industry and academia to share raw, deidentified data from late-phase oncology clinical trials using comparator-arm data sets. These data are likely to be hypothesis generating or hypothesis confirming but, notably, do not take the place of performing a well-designed trial to address a specific hypothesis. Prospective providers of data to PDS complete and sign a data sharing agreement that includes a description of the data they propose to upload, and then they follow easy instructions on the website for uploading their deidentified data. The SAS Institute has also collaborated with the initiative to provide intrinsic analytic tools accessible within the website itself. As of October 2014, the PDS website has available data from 14 cancer clinical trials covering 9,000 subjects, with hopes to further expand the database to include more than 25,000 subject accruals within the next year. PDS differentiates itself from other data-sharing initiatives by its degree of openness, requiring submission of only a brief application with background information of the individual requesting access and agreement to terms of use. Data from several different sponsors may be pooled to develop a comprehensive cohort for analysis. In order to protect patient privacy, data providers in the U.S. are responsible for deidentifying data according to standards set forth by the Privacy Rule of the U.S. Health Insurance Portability and Accountability Act of 1996. USING DATA SHARING TO IMPROVE OUTCOMES IN CANCER THE "PROSTATE CANCER CHALLENGE": Control-arm data of several studies among patients with metastatic castration-resistant prostate cancer (mCRPC) are currently available through PDS. These data sets have multiple potential uses. The "Prostate Cancer Challenge" will ask the cancer research community to use clinical trial data deposited in the PDS website to address key research questions regarding mCRPC. General themes that could be explored by the cancer community are described in this article: prognostic models evaluating the influence of pretreatment factors on survival and patient-reported outcomes; comparative effectiveness research evaluating the efficacy of standard of care therapies, as illustrated in our companion article comparing mitoxantrone plus prednisone with prednisone alone; effects of practice variation in dose, frequency, and duration of therapy; level of patient adherence to elements of trial protocols to inform the design of future clinical trials; and age of subjects, regional differences in health care, and other confounding factors that might affect outcomes.

POTENTIAL LIMITATIONS AND METHODOLOGICAL CHALLENGES

The number of data sets available and the lack of experimental-arm data limit the potential scope of research using the current PDS. The number of trials is expected to grow exponentially over the next year and may include multiple cancer settings, such as breast, colorectal, lung, hematologic malignancy, and bone marrow transplantation. Other potential limitations include the retrospective nature of the data analyses performed using PDS and its generalizability, given that clinical trials are often conducted among younger, healthier, and less racially diverse patient populations. Methodological challenges exist when combining individual patient data from multiple clinical trials; however, advancements in statistical methods for secondary database analysis offer many tools for reanalyzing data arising from disparate trials, such as propensity score matching. Despite these concerns, few if any comparable data sets include this level of detail across multiple clinical trials and populations.

CONCLUSION

Access to large, late-phase, cancer-trial data sets has the potential to transform cancer research by optimizing research efficiency and accelerating progress toward meaningful improvements in cancer care. This type of platform provides opportunities for unique research projects that can examine relatively neglected areas and that can construct models necessitating large amounts of detailed data. The full potential of PDS will be realized only when multiple tumor types and larger numbers of data sets are available through the website.

IgE antibodies to alpha-gal in the general adult population: relationship with tick bites, atopy, and cat ownership

BACKGROUND

The carbohydrate alpha-gal epitope is present in many animal proteins, including those of red meat and animal immunoglobulins, such as cat IgA. Systemic anaphylaxis to the alpha-gal epitope has recently been described.

OBJECTIVE

To investigate and compare the prevalence of alpha-gal-specific (s)IgE and its associated factors in the general adult population from two separated (Northern and Southern) European regions (Denmark and Spain, respectively).

METHODS

Cross-sectional study of 2297 and 444 randomly selected adults from 11 municipalities in Denmark and one in Spain. Alpha-gal sIgE was assessed by ImmunoCAP to bovine thyroglobulin. Additional assessments included a panel of skin prick test (SPT) to common aeroallergens and epidemiological factors, including the history of tick bites in the Danish series.

RESULTS

The prevalence of positive (≥ 0.1 kUA /L) sIgE to alpha-gal was 5.5% and 8.1% in the Danish and Spanish series, respectively. The prevalence of sIgE ≥ 0.35 kUA /L was 1.8% and 2.2% in Denmark and Spain, respectively. Alpha-gal sIgE positivity was associated with pet ownership in both series and, particularly, cat ownership (data available in the Danish series). Alpha-gal sIgE positivity was associated with atopy (SPT positivity) in both series, although it was not associated with SPT positivity to cat or dog dander. Alpha-gal sIgE positivity was strongly associated with a history of tick bites.

CONCLUSIONS AND CLINICAL RELEVANCE

The prevalence of alpha-gal sIgE antibodies in these general adult European populations is similarly low. The presence of alpha-gal sIgE antibodies is associated with a history of tick bites, atopy, and cat ownership.

Human antibody response to N-glycans present on plant-made influenza virus-like particle (VLP) vaccines

BACKGROUND

Plant-made biotherapeutics are gathering momentum and some plant glycoproteins are allergens. Glycans with core β1-2xylose and α1,3fucose motifs and antennae terminated by mannose residues (e.g.: MMXF) are found on several plant allergens and can cross-react with glyco-epitopes from other sources. To date, reactivity to these cross-reactive determinants has not been associated with clinical symptoms.

OBJECTIVE

We produced VLP vaccines bearing the hemagglutinin(HA) of H5(A/Indonesia/5/05) or H1(A/California/07/09) influenza viruses by transfection of Nicotiana benthamiana. Subjects enrolled in Phase I/II trials were followed for evidence of allergy/hypersensitivity and development of antibodies against plant glyco-epitopes.

METHODS

A total of 280/349 subjects received either one (H1) or 2 doses (H5) of vaccine (5-45 μg of HA/dose) intramuscularly including 40 with pre-existing plant allergies. Subjects were monitored for 6 months. IgG and IgE to plant glyco-epitopes were measured by ELISA using corn-/egg-derived avidin and bromelain as target antigens.

RESULTS

No subject developed allergic/hypersensitivity symptoms. Some (34%) developed transient IgG and, in some cases IgE, to plant glyco-epitopes but no subject mounted an IgE response to the MMXF motif. Antibodies returned to baseline by 6 months in most subjects.

CONCLUSION

VLP vaccines bearing influenza HA glycoproteins can elicit transient IgG and, in some cases, IgE responses that are not associated with either the development or worsening of allergic/hypersensitivity symptoms.

Food allergy: a practice parameter update-2014

This parameter was developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma & Immunology (JCAAI). The AAAAI and the ACAAI have jointly accepted responsibility for establishing "Food Allergy: A practice parameter update-2014." This is a complete and comprehensive document at the current time. The medical environment is a changing one, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, ACAAI, and JCAAI. These parameters are not designed for use by pharmaceutical companies in drug promotion.

Minimizing fucosylation in insect cell-derived glycoproteins reduces binding to IgE antibodies from the sera of patients with allergy

The baculovirus/insect cell system has proven to be a very powerful tool for the expression of several therapeutics. Nevertheless, these products sometimes suffer from reduced biological activity and unwanted side effects. Several studies have demonstrated that glycosylation can greatly influence the structure, function, half-life, antigenicity and immunogenicity of various glycoproteins. Yet, the glycosylation pattern of insect cell-derived products is not favorable for many applications. Especially, the presence of core α1,3-linked fucose bears the risk of causing immediate hypersensitivity reactions in patients with allergy. In this study, we evaluated the impact of fucose residues on the allergenic potential of an insect cell-expressed vaccine candidate. In order to block the GDP-L-fucose de novo synthesis pathway, we integrated the Pseudomonas aeruginosa GDP-6-deoxy-D-lyxo-4-hexulose reductase (RMD) gene into a baculovirus backbone. This virus was then used for the expression of soluble influenza A virus hemagglutinin (HA). Expression studies showed that the co-expression of RMD did not influence the overall level of recombinant protein secretion. We confirmed the result of our strategy by analyzing PNGase A-released N-glycans using MALDI-TOF-MS. In order to evaluate the biological impact of defucosylation of influenza HA we tested the binding activity of IgE derived from the sera of patients with allergy to the purified antigen. The non-fucosylated HA showed a 10-fold decrease in IgE binding levels as compared to wildtype variants.

Tick bites and red meat allergy

PURPOSE OF REVIEW

A novel form of anaphylaxis has been described that is due to IgE antibody (Ab) directed against a mammalian oligosaccharide epitope, galactose-alpha-1,3-galactose (alpha-gal). Ongoing work regarding the cause and distribution of this IgE response is reviewed.

RECENT FINDINGS

Our recent work has identified a novel IgE Ab response that has been associated with two distinct forms of anaphylaxis: immediate-onset anaphylaxis during first exposure to intravenous cetuximab and delayed-onset anaphylaxis 3-6 h after ingestion of mammalian food products (e.g. beef and pork). Further studies strongly suggested that tick bites were a cause, if not the only significant cause, of IgE Ab responses to alpha-gal in the United States and internationally.

SUMMARY

Large numbers of patients with IgE Ab to alpha-gal continue to be identified in the USA and globally. Clinicians should be aware of this IgE response as the reactions often appear to be idiopathic because of the significant delay between eating mammalian meat and the appearance of symptoms.

Laminin γ-1 and collagen α-1 (VI) chain are galactose-α-1,3-galactose-bound allergens in beef

BACKGROUND

Sensitization to the carbohydrate galactose-α-1,3-galactose (α-Gal) has been reported in patients with beef allergy. However, the proteins responsible for this allergy have not yet been identified. This study aimed to identify beef proteins that predominantly react with serum IgE in Japanese patients with beef allergy.

METHODS

Sera were collected from 29 patients with beef allergy who had allergic reaction(s) such as urticaria, abdominal pain, vomiting, and anaphylactic shock after ingestion of beef and pork; the sera tested positive for IgE against beef and pork. IgE-binding proteins were detected by immunoblotting sera from the patients and identified using a combination of two-dimensional gel electrophoresis and peptide mass fingerprinting techniques. The involvement of carbohydrate in the binding of IgE to allergens was examined by periodate treatment and an inhibition assay with cetuximab by immunoblotting. Specific IgE binding to cetuximab was measured using the CAP-fluorescent enzyme immunoassay.

RESULTS

Two IgE-binding proteins (240 kDa and 140 kDa) were detected in beef extract and identified as laminin γ-1 and the collagen α-1 (VI) chain from Bos taurus, respectively. Periodate treatment or the inhibition assay resulted in the loss of IgE binding to these proteins. Immunoblotting with anti-α-Gal antibody revealed the presence of α-Gal on the 240- and 140-kDa beef proteins. The amount of IgE bound to cetuximab was significantly correlated with that to beef in the patients with beef allergy.

CONCLUSION

The carbohydrate moiety (α-Gal) on laminin γ-1 and collagen α-1 (VI) chain are possibly common IgE-reactive proteins in the Japanese patients with beef allergy.

Development of hypoallergenic galacto-oligosaccharides on the basis of allergen analysis

Galacto-oligosaccharides (GOSs) are recognized as prebiotics beneficial to human health through their abilities to modulate gut microbiota. On the other hand, it has been reported that immediate allergic reactions are caused by a GOS product (Bc-GOS) produced by treating lactose with β-galactosidase derived from Bacillus circulans. The objective of this study was to create a safer GOS product that is less likely to cause GOS-induced allergy (GOS-AL). First, we identified two derivatives of tetrasaccharide sugar chains in Bc-GOS as the factors responsible for GOS-AL by histamine release test (HRT) using blood samples obtained from two GOS-AL patients. Through our search for non-allergic GOS, we developed a new GOS product, SK-GOS, which was produced by catalyzing lactose with β-galactosidase derived from Sporobolomyces singularis and Kluyveromyces lactis. We regard it as a hypoallergic and safe GOS product that does not cause GOS-AL.

Food Allergy

Food allergy has established itself as a matter of significant public health importance and relevance. It has had substantial impacts across the world and continues to represent the most common cause of anaphylaxis seen in emergent settings. However, its increasing incidence has yielded a silver lining of increased interest and investment, which has powered major research in the field. Much has been learned about food allergy as a result. Recent work has elicited increased understanding about food allergy prevalence, mechanisms, and risk factors. In turn, this has allowed for application of this understanding to potential treatments. Current practice of food allergy treatment through restricted exposure may ultimately be replaced with novel therapies including, perhaps ironically, introduction of the allergenic foods in question. This review presents broad highlights of the rapidly increasing understanding into food allergy mechanisms and experimental therapies.

Incidence of cetuximab-related infusion reactions in oncology patients treated at the University of North Carolina Cancer Hospital

PURPOSE

The primary purpose of this study was to determine the rate of infusion reactions to cetuximab in oncology patients treated at the University of North Carolina Cancer Hospital. Secondarily, we sought to evaluate predictors of grade 3-4 hypersensitivity, including geography.

METHODS

Data were collected by retrospective chart review for patients treated with cetuximab at the University of North Carolina Cancer Hospital between 15 November 2006 and 31 December 2010. Data were analyzed for occurrence of hypersensitivity reaction in 125 patients with various cancer types.

RESULTS

Of the 125 subjects, 31 (24.8%) experienced an infusion reaction of any grade. Of 125, 18 (14.4%) experienced a grade 3 or 4 reaction. The odds ratio for patients with an allergy history having a grade 3 or 4 reaction was 2.57 (95% CI 0.93 to 7.09, p = 0.07). Pretreatment with steroids was associated with absence of grade 3 or 4 reaction with an odds ratio of 0.21 (95% CI 0.05 to 0.83, p = 0.04). Mapping of reaction rates by county revealed higher rates in some of the more rural counties of North Carolina, however, statistical power was lacking.

CONCLUSIONS

Rates of hypersensitivity reaction at UNC are similar to rates seen in other areas of the southeastern United States and higher than in other regions of the United States and Europe. Rates of both hypersensitivity reactions and grade 3 to 4 hypersensitivity reactions have not substantially changed over time. Geography, allergy history, and perhaps smoking or cancer type may help predict who will react to cetuximab. Steroids should be strongly considered as premedication in addition to diphenhydramine.

Inhibition of IgE binding to cross-reactive carbohydrate determinants enhances diagnostic selectivity

Background

Allergy diagnosis by determination of allergen-specific IgE is complicated by clinically irrelevant IgE, of which the most prominent example is IgE against cross-reactive carbohydrate determinants (CCDs) that occur on allergens from plants and insects. Therefore, CCDs cause numerous false-positive results. Inhibition of CCDs has been proposed as a remedy, but has not yet found its way into the routine diagnostic laboratory. We sought to provide a simple and affordable procedure to overcome the CCD problem.

Methods

Serum samples from allergic patients were analysed for allergen-specific IgEs by different commercial tests (from Mediwiss, Phadia and Siemens) with and without a semisynthetic CCD blocker with minimized potential for nonspecific interactions that was prepared from purified bromelain glycopeptides and human serum albumin.

Results

Twenty two per cent of about 6000 serum samples reacted with CCD reporter proteins. The incidence of anti-CCD IgE reached 35% in the teenage group. In patients with anti-CCD IgE, application of the CCD blocker led to a clear reduction in read-out values, often below the threshold level. A much better correlation between laboratory results and anamnesis and skin tests was achieved in many cases. The CCD blocker did not affect test results where CCDs were not involved.

Conclusion

Eliminating the effect of IgEs directed against CCDs by inhibition leads to a significant reduction in false-positive in vitro test results without lowering sensitivity towards relevant sensitizations. Application of the CCD blocker may be worthwhile wherever natural allergen extracts or components are used.