University of Tübingen

Longitudinal Follow-up Reveals Peripheral Immunological Changes Upon Tick Bite in α-Gal-Sensitized Individuals.

α-Gal syndrome is characterized by specific IgE (sIgE) antibodies to the carbohydrate galactose-α-1,3-galactose (α-Gal) and delayed onset of allergic symptoms after ingestion of mammalian meat. While tick bites are assumed to mediate sensitization, the immune response to tick bites has not yet been investigated. Objective: To investigate the peripheral immune response to tick bites in humans over time. In a longitudinal cohort study, immunological reactions associated with tick bites (Ixodes species) were analyzed within 1 day (V1), 2 weeks (V2), 1 month (V3), and 3 months (V4) after the occurrence of a bite. sIgE, sIgG, and sIgG subclass levels, as well as 10 cytokines, were quantified. Deep immune phenotyping was performed using mass cytometry. A total of 4 controls and 10 patients were bitten by a tick and followed up over 3 months. None of the controls developed sIgE to α-Gal, and sIgE increased in all patients from V1 until V2/V3, as did IL-8 levels. We noted a significant increase in CD19+ B cells and B-cell subpopulations, as well as a decrease in γδ CD56+ T cells in patients between V0 and V1. At V1, frequencies of plasmacytoid dendritic cells (pDCs) and γδ CD56+ T cells were lower in patients than in controls. Our study provides evidence of significant changes in several immune cell populations in α-Gal-sensitized patients, along with increased levels of IL-8 and sIgE. This is the first exploratory study to investigate longitudinal peripheral immune profiles in patients and controls bitten by ticks.

Recurrent tick bites induce high IgG1 antibody responses to α-Gal in sensitized and non-sensitized forestry employees in Luxembourg.

The α-Gal syndrome (AGS) is characterized by the presence of specific IgE-antibodies to the carbohydrate galactose-α-1,3-galactose (α-Gal). Sensitization to α-Gal has been associated with tick bites and individuals exposed to ticks have an elevated risk of sensitization. The aim of this study was to analyze IgG and IgE antibody responses to α-Gal in a high-risk cohort of forestry employees (FE) in Luxembourg. Questionnaires and serum samples of FE from Luxembourg (n = 219) were retrospectively analyzed. α-Gal specific IgE was quantified by ImmunoCAP, α-Gal specific IgG and subclasses IgG were determined by ELISA. Additionally, sera from population-based controls (n = 150) and two groups of food-allergic patients, patients with AGS (n = 45) and fish-allergic patients (n = 22) were assessed for IgG antibody responses to α-Gal and cod extract. Twenty-one percent of FE was sensitized to α-Gal (sIgE ≥ 0.1 kU/L). Both sensitized and non-sensitized FE exhibited high levels of α-Gal specific IgG, IgG1 and IgG3 compared with controls, indicating a stimulation of IgG responses by recurrent tick bites, independent of the sensitization status. AGS patients had the highest levels of IgG1 and IgG2 antibodies, whereas the profile of fish-allergic patients was similar to the profile of the controls for which anti-α-Gal responses were dominated by IgG2 antibodies. α-Gal sIgG4 levels were either very low or undetectable in all groups. Our study provides evidence for a continuous stimulation of α-Gal related immune responses by repeated tick bites, translating into highly elevated levels of IgG1 antibodies directed against α-Gal.

IgE and anaphylaxis specific to the carbohydrate alpha-gal depend on IL-4.

Alpha-gal (Galα1-3Galβ1-4GlcNAc) is a carbohydrate with the potential to elicit fatal allergic reactions to mammalian meat and drugs of mammalian origin. This type of allergy is induced by tick bites, and therapeutic options for this skin-driven food allergy are limited to the avoidance of the allergen and treatment of symptoms. Thus, a better understanding of the immune mechanisms resulting in sensitization through the skin is crucial, especially in the case of a carbohydrate allergen for which underlying immune responses are poorly understood. We aimed to establish a mouse model of alpha-gal allergy for in-depth immunologic analyses. Alpha-galactosyltransferase 1-deficient mice devoid of alpha-gal glycosylations were sensitized with the alpha-gal-carrying self-protein mouse serum albumin by repetitive intracutaneous injections in combination with the adjuvant aluminum hydroxide. The role of basophils and IL-4 in sensitization was investigated by antibody-mediated depletion. Alpha-gal-sensitized mice displayed increased levels of alpha-gal-specific IgE and IgG and developed systemic anaphylaxis on challenge with both alpha-gal-containing glycoproteins and glycolipids. In accordance with alpha-gal-allergic patients, we detected elevated numbers of basophils at the site of sensitization as well as increased numbers of alpha-gal-specific B cells, germinal center B cells, and B cells of IgE and IgG isotypes in skin-draining lymph nodes. By depleting IL-4 during sensitization, we demonstrated for the first time that sensitization and elicitation of allergy to alpha-gal and correspondingly to a carbohydrate allergen is dependent on IL-4. These findings establish IL-4 as a potential target to interfere with alpha-gal allergy elicited by tick bites.

α-Gal present on both glycolipids and glycoproteins contributes to immune response in meat-allergic patients.

The α-Gal syndrome is associated with the presence of IgE directed to the carbohydrate galactose-α-1,3-galactose (α-Gal) and is characterized by a delayed allergic reaction occurring 2 to 6 hours after ingestion of mammalian meat. On the basis of their slow digestion and processing kinetics, α-Gal-carrying glycolipids have been proposed as the main trigger of the delayed reaction. We analyzed and compared the in vitro allergenicity of α-Gal-carrying glycoproteins and glycolipids from natural food sources. Proteins and lipids were extracted from pork kidney (PK), beef, and chicken. Glycolipids were purified from rabbit erythrocytes. The presence of α-Gal and IgE binding of α-Gal-allergic patient sera (n = 39) was assessed by thin-layer chromatography as well as by direct and inhibition enzyme-linked immunosorbent assay. The in vitro allergenicity of glycoproteins and glycolipids from different meat extracts was determined by basophil activation test. Glycoprotein stability was evaluated by simulated gastric and intestinal digestion assays. α-Gal was detected on glycolipids of PK and beef. Patient IgE antibodies recognized α-Gal bound to glycoproteins and glycolipids, although binding to glycoproteins was more potent. Rabbit glycolipids were able to strongly activate patient basophils, whereas lipid extracts from PK and beef were also found to trigger basophil activation, but at a lower capacity compared to the respective protein extracts. Simulated gastric digestion assays of PK showed a high stability of α-Gal-carrying proteins in PK. Both α-Gal-carrying glycoproteins and glycolipids are able to strongly activate patient basophils. In PK and beef, α-Gal epitopes seem to be less abundant on glycolipids than on glycoproteins, suggesting a major role of glycoproteins in delayed anaphylaxis upon consumption of these food sources.

Spatial distribution of alpha-gal in Ixodes ricinus - A histological study.

Alpha-gal syndrome is a complex allergic disease in humans that is caused by specific IgE (sIgE) against the carbohydrate galactose-α-1,3-galactose (alpha-gal). Tick saliva contains alpha-gal, and tick bites are considered a major cause of the induction of alpha-gal-sIgE. The origin of alpha-gal in tick saliva remains unclarified. The presence of alpha-gal in tick tissue was visualized in this study to provide an overview of the spatial distribution of alpha-gal and to further elucidate the origin of alpha-gal in tick saliva. Fed and unfed Ixodes ricinus females were examined by histology, immunohistochemistry, immunofluorescence, transmission electron microscopy and immunoelectron microscopy using the alpha-gal-specific monoclonal antibody M86 and Marasmius oreades agglutinin (MOA) lectin. Alpha-gal epitopes were detected in the midgut, hemolymph and salivary glands, and the immunofluorescence analysis revealed signs of the endocytosis of alpha-gal-containing constituents during the process of hematophagy. Alpha-gal epitopes in endosomes of the digestive gut cells of the ticks were observed via immunoelectron microscopy. Alpha-gal epitopes were detected in dried droplets of hemolymph from unfed ticks. Intense staining of alpha-gal epitopes was found in type II granular acini of the salivary glands of fed and unfed ticks. Our data suggest that alpha-gal is not ubiquitously expressed in tick tissue but is present in both fed and unfed ticks. The findings also indicate that both the metabolic incorporation of constituents from a mammalian blood meal and endogenous production contribute to the presence of alpha-gal epitopes in ticks.

Radiochemotherapy with or without cetuximab for unresectable esophageal cancer: final results of a randomized phase 2 trial (LEOPARD-2).

To investigate the efficacy and toxicity of cetuximab when added to radiochemotherapy for unresectable esophageal cancer. This randomized phase 2 trial (clinicaltrials.gov, identifier NCT01787006) compared radiochemotherapy plus cetuximab (arm A) to radiochemotherapy (arm B) for unresectable esophageal cancer. Primary objective was 2‑year overall survival (OS). Arm A was considered insufficiently active if 2‑year OS was ≤40% (null hypothesis = H), and promising if the lower limit of the 95% confidence interval was >45%. If that lower limit was >40%, H was rejected. Secondary objectives included progression-free survival (PFS), locoregional control (LC), metastases-free survival (MFS), response, and toxicity. The study was terminated early after 74 patients; 68 patients were evaluable. Two-year OS was 71% in arm A (95% CI: 55-87%) vs. 53% in arm B (95% CI: 36-71%); H was rejected. Median OS was 49.1 vs. 24.1 months (p = 0.147). Hazard ratio (HR) for death was 0.60 (95% CI: 0.30-1.21). At 2 years, PFS was 56% vs. 44%, LC 84% vs. 72%, and MFS 74% vs. 54%. HRs were 0.51 (0.25-1.04) for progression, 0.43 (0.13-1.40) for locoregional failure, and 0.43 (0.17-1.05) for distant metastasis. Overall response was 81% vs. 69% (p = 0.262). Twenty-six and 27 patients, respectively, experienced at least one toxicity grade ≥3 (p = 0.573). A significant difference was found for grade ≥3 allergic reactions (12.5% vs. 0%, p = 0.044). Given the limitations of this trial, radiochemotherapy plus cetuximab was feasible. There was a trend towards improved PFS and MFS. Larger studies are required to better define the role of cetuximab for unresectable esophageal cancer.

The History of Carbohydrates in Type I Allergy.

Although first described decades ago, the relevance of carbohydrate specific antibodies as mediators of type I allergy had not been recognized until recently. Previously, allergen specific IgE antibodies binding to carbohydrate epitopes were considered to demonstrate a clinically irrelevant cross-reactivity. However, this changed following the discovery of type I allergies specifically mediated by oligosaccharide structures. Especially the emerging understanding of red meat allergy characterized by IgE directed to the oligosaccharide alpha-gal showed that carbohydrate-mediated reactions can result in life threatening systemic anaphylaxis which in contrast to former assumptions proves a high clinical relevance of some carbohydrate allergens. Within the scope of this review article, we illustrate the historical development of carbohydrate-allergen-research, reaching from only diagnostically relevant crossreactive-carbohydrate-determinants to clinically important antigens mediating type I allergy. Focusing on clinical and immunological features of the alpha-gal syndrome, we highlight the discovery of oligosaccharides as potentially highly immunogenic antigens and mediators of type I allergy, report what is known about the route of sensitization and the immunological mechanisms involved in sensitization and elicitation phase of allergic responses as well as currently available diagnostic and therapeutic tools. Finally, we briefly report on carbohydrates being involved in type I allergies different from alpha-gal.

Prevalence and Impact of Type I Sensitization to Alpha-Gal in Patients Consulting an Allergy Unit.

Alpha-gal syndrome is a complex allergy with high clinical relevance regarding mammalian-derived food and drugs and is characterized by the presence of IgE antibodies directed at the carbohydrate galactose-α-1,3-galactose. As not all alpha-gal sIgE-positive individuals pre-sent clinical symptoms upon consumption of mammalian meat, the diagnostic value of alpha-gal sIgE has yet to be clarified. To investigate the prevalence of alpha-gal-sIgE positivity among allergy patients, examine the impact of tick bites as associated risk factors and determine the diagnostic value of alpha-gal-sIgE positivity. A retrospective cross-sectional study evaluating patients in the Allergy Unit was performed. Alpha-gal-sIgE levels were assessed by ImmunoCAP assay. Exposure to tick bites was assessed by a questionnaire. A receiver operating characteristics (ROC) curve analysis was performed to determine the diagnostic value of alpha-gal sIgE for the diagnosis of alpha-gal syndrome. In the study population (n = 1369), the overall prevalence of alpha-gal-sIgE-positive (≥0.10 kUA/L) individuals was 19.9%, and the highest prevalence (30.2%) was found in patients with insect venom allergies. A reported tick bite within the 12 months prior to blood sampling significantly increased the risk of alpha-gal-sIgE positivity (OR 2.084). The ROC curve analysis indicated alpha-gal sIgE ≥0.54 kUA/L as the optimal cutoff point for assessing the diagnostic value of alpha-gal syndrome in allergy patients. In allergy care settings, alpha-gal-sIgE positivity is a common finding. Alpha-gal sIgE is a sensitive marker in the diagnosis of alpha-gal syndrome but has limited predictive value for the characteristics or severity of this allergy.

Role and Mechanism of Galactose-Alpha-1,3-Galactose in the Elicitation of Delayed Anaphylactic Reactions to Red Meat.

The alpha-Gal (α-Gal) syndrome is characterized by the presence of IgE antibodies directed at the carbohydrate galactose-alpha-1,3-galactose (α-Gal). In this article, we review the presence of α-Gal in food and non-food sources; we discuss the evolutionary context of the antibody response to α-Gal and highlight immune responses to α-Gal and other carbohydrates. IgE antibodies have been associated with delayed allergy to red meat. In addition to food, drugs, and other products of animal origin are increasingly perceived as a risk for patients sensitized to α-Gal. The link between tick bites and anti-α-Gal IgE-antibody production that has been established first by epidemiological studies has now been confirmed in mouse models. The anti-α-Gal immune response is complex and characterized by a unique feature. IgM and IgG antibodies have been found to confer protection against pathogens whereas the IgE-response to α-Gal is detrimental and causes severe reactions upon exposure to mammalian meat and other products.

The basophil activation test differentiates between patients with alpha-gal syndrome and asymptomatic alpha-gal sensitization.

Galactose-alpha-1,3-galactose (alpha-gal) syndrome is characterized by the presence of serum specific IgE antibodies to alpha-gal and delayed type I allergic reactions to the carbohydrate alpha-gal after consumption of mammalian (red) meat products and drugs of mammalian origin. Diagnostics currently rely on patient history, skin tests, determination of serum specific IgE antibodies, and oral food or drug challenges. We sought to assess the utility of different basophil parameters (basophil reactivity and sensitivity, the ratio of the percentage of CD63 basophils induced by the alpha-gal-containing allergen to the percentage of CD63 basophils after stimulation with anti-FcεRI antibody [%CD63/anti-FcεRI], and area under the dose-response curve [AUC]) as biomarkers for the clinical outcome of patients with alpha-gal syndrome compared with subjects with asymptomatic alpha-gal sensitization. In addition to routine diagnostics, a basophil activation test (Flow CAST) with different concentrations of alpha-gal-containing allergens (eg, commercially available alpha-gal-carrying proteins and pork kidney extracts) was performed in 21 patients with alpha-gal syndrome, 12 alpha-gal-sensitized subjects, and 18 control subjects. Alpha-gal-containing allergens induced strong basophil activation in a dose-dependent manner in patients. Basophil reactivity at distinct allergen concentrations, the %CD63/anti-FcεRI ratio across most allergen concentrations, the AUC of dose-response curves, and basophil allergen threshold sensitivity (CD-sens) with pork kidney extract were significantly higher in patients with alpha-gal syndrome compared with those in sensitized subjects. All parameters were negative in control subjects. The basophil activation test should be considered as an additional diagnostic test before performing time-consuming and potentially risky oral provocation tests. The %CD63/anti-FcεRI ratio for all allergens and AUCs for pork kidney were the best parameters for distinguishing patients with alpha-gal syndrome from subjects with asymptomatic alpha-gal sensitization.

Drugs of porcine origin-A risk for patients with α-gal syndrome?

Meat allergy associated with galactosyl-α-(1,3)-galactose (α-Gal)-Closing diagnostic gaps by anti-α-Gal IgE immune profiling.

Glycoproteins and glycolipids of some mammalian species contain the disaccharide galactosyl-α-(1,3)-galactose (α-Gal). It is known that α-Gal is immunogenic in humans and causes glycan-specific IgG and also IgE responses with clinical relevance. α-Gal is part of the IgE-reactive monoclonal therapeutic antibody cetuximab (CTX) and is associated with delayed anaphylaxis to red meat. In this study, different α-Gal-containing analytes are examined in singleplex and multiplex assays to resolve individual sensitization patterns with IgE against α-Gal. Three serum groups, α-Gal-associated meat allergy (MA) patients, idiopathic anaphylaxis (IA) patients with suspected MA, and non-meat-allergic healthy control individuals (HC), were analyzed via singleplex allergy diagnostics and a newly established immunoblot diagnostic system. The new dot blot detection system resolved individual IgE sensitization profiles for α-Gal-containing analytes CTX, bovine thyroglobulin (Bos d TG), and human serum albumin (HSA)-conjugated α-Gal. Singleplex allergy diagnostics using the α-Gal analytes CTX and Bos d TG confirms the history of MA patients in 91% and 88% of the cases, respectively. A novel dot blot-based assay system for the detection of IgE against α-Gal reveals individual IgE sensitization profiles for α-Gal-containing analytes. An α-Gal-associated IgE cross-reactivity profile (IgE against CTX, Bos d TG, and HSA-α-Gal) was identified, which is associated with MA. Detection of individual sensitization patterns with different α-Gal-containing analytes provides the basis for an individual allergy diagnosis for α-Gal-sensitized patients. Higher amounts of α-Gal in pork and beef innards compared to muscle meat as indicated by a higher staining intensity are a plausible explanation for the difference in allergic symptom severity.

Prevalence of type I sensitization to alpha-gal in forest service employees and hunters.

The production of IgE molecules specific to the carbohydrate galactose-α-1,3-galactose (alpha-gal) is known to induce delayed anaphylaxis against mammalian meat. Tick bites constitute the primary sensitization source, as ticks transfer alpha-gal in their saliva to a host during a bite. The reported prevalence of alpha-gal-specific IgE (alpha-gal-sIgE) positivity varies between different populations from diverse geographic regions. To investigate the prevalence of alpha-gal-sIgE positivity in a population of forest service employees who are highly exposed to ticks in comparison with a residential population and a historic sample. A cross-sectional study evaluating 300 forest service employees and hunters from southwest Germany was performed. Alpha-gal-sIgE levels were assessed by ImmunoCAP assay. The prevalence of alpha-gal-sIgE-positive individuals was compared with a matched cohort composed of a residential population and blood samples from forest service employees collected 15 years ago. In the study population, the prevalence of alpha-gal-sIgE-positive (≥0.10 kU /L) individuals was 35.0%, whereas the prevalence of individuals with alpha-gal-sIgE levels ≥0.35 kU /L was 19.3%. Alpha-gal-sIgE positivity was associated with total IgE levels and recent tick bites. Mammalian meat-induced delayed anaphylaxis was found in 8.6% of the participants with alpha-gal-sIgE levels ≥0.35 kU /L. For forest service employees and hunters, the odds ratio for alpha-gal-sIgE positivity was 2.48 compared to the residential population. The prevalence of alpha-gal-sIgE positivity in the current and historic cohort was comparable. Forest service employees and hunters compose a population with a high prevalence of alpha-gal-sIgE positivity and carry a considerable risk of red meat allergy.

Alpha-gal is a possible target of IgE-mediated reactivity to antivenom.

Antivenoms are mammalian immunoglobulins with the ability to neutralize snake venom components and to mitigate the progression of toxic effects. Immediate hypersensitivity to antivenoms often occurs during the first administration of these heterologous antibodies. A comparable clinical situation occurred after introduction of cetuximab, a chimeric mouse-human antibody, for cancer treatment. The carbohydrate epitope galactose-alpha-1,3-galactose, located on the Fab region of cetuximab, was identified as the target responsible for IgE reactivity. To investigate whether serum IgE antibodies directed to the α-gal epitope are associated with hypersensitivity to equine antivenoms. Antivenoms were screened for α-gal epitopes via immunoblot and in comparison with cetuximab and pork kidney by IgE reactivity assays. Basophil activation tests were used to investigate reactivity to antivenoms in samples from 20 patients with specific IgE antibodies to α-gal and 10 controls. Additional IgE detection, IgE inhibition, ImmunoCAP inhibition, and skin prick tests were performed using samples from selected patients. Both antivenoms and cetuximab induced positive skin prick test results in patients with sIgE to α-gal. Alpha-gal epitopes were detected by immunoblotting on antivenoms. Measurements of IgE reactivity and ImmunoCAP inhibition indicated that the antivenoms contained lower α-gal contents than cetuximab. Deglycosylation assays and IgE inhibition tests confirmed that IgE-mediated reactivity to antivenom is associated with α-gal. Antivenoms, pork kidney, and cetuximab activated basophils from patients with IgE to α-gal. Alpha-gal is a potential target of IgE-mediated reactivity to equine antivenom and a possible cause of the high incidence of hypersensitivity reactions during the first application of equine antivenom.

Prevalence of type I sensitization to alpha-gal in forest service employees and hunters: Is the blood type an overlooked risk factor in epidemiological studies of the α-Gal syndrome?

Two galactose-α-1,3-galactose carrying peptidases from pork kidney mediate anaphylactogenic responses in delayed meat allergy.

Serum IgE antibodies directed at galactose-α-1,3-galactose (α-Gal) are associated with a novel form of delayed anaphylaxis occurring upon consumption of red meat or innards. Pork kidney is known as the most potent trigger of this syndrome, but the culprit allergens have not yet been identified. The aim of this study was the identification and characterization of pork kidney proteins mediating delayed anaphylactic reactions through specific IgE to α-Gal. A cohort of 59 patients with specific IgE to α-Gal was screened by immunoblot for IgE-reactive proteins in pork kidney. Proteins were identified by peptide mass fingerprinting. Isolated proteins were assayed in ELISA and ELISA inhibition, basophil activation and skin prick test. Several IgE-binding proteins of high molecular weight (100- >200 kDa) were detected in pork kidney extracts by immunoblot using patient sera and an anti-α-Gal antibody. Two major IgE-binding proteins were identified as porcine angiotensin-I-converting enzyme (ACE I) and aminopeptidase N (AP-N). Reactivity of patient sera and anti-α-Gal antibody to both proteins was abolished by carbohydrate oxidation. The α-Gal IgE epitopes were resistant to heat denaturation. Pork kidney extract, isolated ACE I, and AP-N were able to activate patient basophils and elicit positive responses in skin prick tests. Two cell-membrane proteins carrying α-Gal epitopes were identified in pork kidney. For the first time, isolated meat proteins were shown to induce basophil activation in patients with delayed anaphylaxis to red meat providing further confirmation for the clinical relevance of these α-Gal-carrying proteins.

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.

Cross-reactivity to fish and chicken meat - a new clinical syndrome.

Fish is one of the most allergenic foods. While clinical cross-reactivity among different fishes is a widely accepted feature of fish allergy, associations with other food allergies are not well understood. This study aims at analyzing the relevance of clinical cross-reactivity between fish and chicken meat in patients with allergy to chicken meat without sensitization to hen's eggs. Patients with food allergy to fish and chicken meat (n = 29) or chicken meat only (n = 7) were recruited. IgE-reactive chicken proteins were identified (Edman, MS analysis) and quantified (ELISA). Allergens were used in IgE ELISA and skin testing. Chicken parvalbumin and two new allergens, aldolase and enolase, were identified at 12, 40, and 50 kDa, respectively. They were recognized by sIgE of 61%, 75%, and 83% of all patient sera which were in the majority of the cases positive for the fish homologues as well. Fish and chicken meat allergens were highly cross-reactive while high inhibition rates with fish or chicken allergens correlated with the patients' primary sensitization to fish or chicken. In cooked or roasted foods, enolase and aldolase were detectable in chicken breast while parvalbumin was detectable in chicken legs and wings. Fish and chicken meat are cross-reactive foods; both fish-allergic and chicken meat-allergic patients might be at risk of developing a food allergy to chicken meat or to fish, respectively. This clinical phenomenon is proposed to be termed 'fish-chicken syndrome' with cross-reactive allergens involved being parvalbumins, enolases, and aldolases.

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.

Mammalian meat allergy: a diagnostic challenge.

Panitumumab: A safe option for oncologic patients sensitized to galactose-α-1,3-galactose.

Galactose-alpha-1,3-galactose sensitization is a prerequisite for pork-kidney allergy and cofactor-related mammalian meat anaphylaxis.

Gelatin-containing sweets can elicit anaphylaxis in a patient with sensitization to galactose-α-1,3-galactose.

The structure of the major cell wall polysaccharide of Bacillus anthracis is species-specific.

In this report we describe the structure of the polysaccharide released from Bacillus anthracis vegetative cell walls by aqueous hydrogen fluoride (HF). This HF-released polysaccharide (HF-PS) was isolated and structurally characterized from the Ames, Sterne, and Pasteur strains of B. anthracis. The HF-PSs were also isolated from the closely related Bacillus cereus ATCC 10987 strain, and from the B. cereus ATCC 14579 type strain and compared with those of B. anthracis. The structure of the B. anthracis HF-PS was determined by glycosyl composition and linkage analyses, matrix-assisted laser desorption-time of flight mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectroscopy. The HF-PSs from all of the B. anthracis isolates had an identical structure consisting of an amino sugar backbone of -->6)-alpha-GlcNAc-(1-->4)-beta-ManNAc-(1-->4)-beta-GlcNAc-(1-->, in which the alpha-GlcNAc residue is substituted with alpha-Gal and beta-Gal at O-3 and O-4, respectively, and the beta-GlcNAc substituted with alpha-Gal at O-3. There is some variability in the presence of two of these three Gal substitutions. Comparison with the HF-PSs from B. cereus ATCC 10987 and B. cereus ATCC 14579 showed that the B. anthracis structure was clearly different from each of these HF-PSs and, furthermore, that the B. cereus ATCC 10987 HF-PS structure was different from that of B. cereus ATCC 14579. The presence of a B. anthracis-specific polysaccharide structure in its vegetative cell wall is discussed with regard to its relationship to those of other Bacillus species.

The hydrophobic mannoside Man alpha 1-6Man alpha 1-S-(CH2)7-CH3 acts as an acceptor for the UDP-Gal:glycosylphosphatidylinositol anchor alpha 1,3-galactosyltransferase of Trypanosoma brucei.

The variant surface glycoproteins (VSGs) of Trypanosoma brucei are attached to the plasma membrane via a glycosylphosphatidylinositol (GPI) membrane anchor. This anchor contains the core sequence ethanolamine-PO4-6Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6myo-inositol, which is conserved in all GPI anchors, and a unique alpha Gal side chain attached to the 3-position of the alpha Man residue adjacent to the alpha GlcN residue. Here we report that trypanosome membranes can catalyse the transfer of Gal from UDP-Gal to the hydrophobic thioglycoside Man alpha 1-6Man alpha 1-S-(CH2)7-CH3. Characterization of the galactosylated products by electrospray mass spectrometry, exoglycosidase digestion and periodate-oxidation studies revealed that the major product was Man alpha 1-6(Gal alpha 1-3)Man alpha 1-S-(CH2)7-CH3. The similarity of this product to part of the mature VSG GPI anchor suggests that the thioglycoside is able to act as an acceptor for the trypanosome-specific UDP-Gal-GPI anchor alpha 1,3-galactosyltransferase.