Diagnosis and Management of Patients with the α-Gal Syndrome

Anaphylaxis: Advances in the Past 10 Years

In the past 10 years, anaphylaxis has grown into its own special area of study within Allergy-Immunology, both at the bench and at the bedside. This review focuses on some of the most clinically relevant advances over the past decade. These include simplified and more inclusive diagnostic criteria for adults and children, uniform definition of biphasic anaphylaxis, and improved systems for objective severity grading. Studies reported in the past decade have led to improved understanding of normal and abnormal regulation of mast cell function, translating into better diagnostic and therapeutic approaches to patients with anaphylaxis. Research has provided improved recognition and treatment of mast cell disorders and has identified a new condition, hereditary α-tryptasemia, that may impact anaphylactic syndromes. We have learned to recognize new causes (α-gal), new pathways (Mas-related G protein-coupled receptor-X2), and many risk factors for severe anaphylaxis. The stability of epinephrine in autoinjectors was reported to be very good for several years after the labeled expiry date, and it can tolerate freezing and thawing. Repeated and prolonged exposure to excessive heat leads to degradation of epinephrine activity. New treatments to prevent severe anaphylaxis have been described, using new ways to block the IgE receptor or modulate intracellular signaling pathways.

Alpha-gal syndrome and delayed anaphylaxis after ingestion of red meat: A case report

α-gal syndrome (AGS) is caused by the intake of products containing α-gal (galactose-α-1,3-galactose) like mammalian meat. Over the last decade, scientific literature about AGS has been increasing, but the true burden of cases is still unknown [1, 2]. In the USA (University of Virginia Allergy Clinic), the number of confirmed cases of AGS was 24 in 2009 [3] and increased to 34,000 in the entire USA by 2019 [4]. As shown in surveys, in Italy AGS is present throughout the country [5]. The literature suggests that a previous tick bite can cause AGS, but in our case it was not possible to demonstrate this association as the patient did not recall any tick bite, even in childhood. After eating red meat, a 56-year-old male patient had developed symptoms such as a generalized urticaria, diarrhea, and faintness, requiring admission to the Emergency Department. The diagnosis was verified using blood CAP-FEIA test and prick-to-prick test. After completing the diagnostic process, we provided the patient with emergency therapy, and auto-injectable adrenaline was prescribed. Despite the diagnosis, the patient ate red meat once again which resulted in severe urticaria 2 hours after the meal, requiring a second visit to the Emergency Room. Now the patient is under follow-up at our Department of Allergy and Clinical Immunology.

Idiopathic Anaphylaxis? Analysis of Data from the Anaphylaxis Registry for West Pomerania Province, Poland

The most common causes of anaphylaxis, according to various authors and depending on the age of the studied groups, are: Hymenoptera venom, food, and medications. Unfortunately, we are not always able to indicate the cause of anaphylaxis. There are data in the literature where as many as 41% of all cases are idiopathic anaphylaxis. Since the introduction of new diagnostic methods such as molecular diagnostics (MD) in our centre, the percentage of idiopathic anaphylaxis in the Anaphylaxis Register has significantly decreased. The purpose of this study was to identify possible causes of idiopathic anaphylaxis in patients with a history of moderate to severe anaphylactic reactions. After using MD, the causative agent was found in another 29 people. The proportion of people with idiopathic anaphylaxis in the Registry decreased from 9.2% to 3.5%. There were no significant differences in the incidence, although men appear to be slightly more common in primary idiopathic anaphylaxis. The mean age of primary idiopathic anaphylaxis was 40 years, but this was as high as 51 for anaphylaxis with alpha-gal allergy. Exercise may or may not be present as a cofactor despite its established role, e.g., in wheat-dependent exercise-induced anaphylaxis (WDEIA). In most of the analyzed cases, i.e., 70%, the reaction took place within an hour. The longest time interval from exposure to the development of symptoms is in the case of alpha-gal allergy; in this analysis, it was at least 5 h after ingestion of the so-called "red meat". Patients are not aware of the disease, or further attacks cannot be prevented. As many as 80% had idiopathic anaphylaxis prior to visiting the centre, and 80% developed anaphylaxis after visiting the centre, which emphasizes the need to not stop the medical team in their search for the causes. As many as 93% of cases required medical intervention, of which adrenaline was used only in 34.5%, antihistamines in 86%, systemic glucocorticosteroids (sCS) in 75%, and fluids in 62% of cases. A total of 83% of patients received an emergency kit for self-administration. Idiopathic anaphylaxis can be resolved as known-cause anaphylaxis after a thorough medical history and, if possible, without exposing the patient after using appropriate, modern in vitro diagnostic methods, including molecular diagnostics. The diagnosis of idiopathic anaphylaxis should extend the diagnosis to include alpha-gal syndrome, LTP syndrome and WDEIA.

Knowledge, attitudes, and practices of Illinois medical professionals related to ticks and tick-borne disease

Background

The rising incidence of tick-borne disease (TBD) underscores the importance of proficiency in TBD diagnosis. Clinicians' knowledge about vector ticks and TBDs in their area may influence whether patients are questioned about potential tick exposure and the consideration of diagnostic testing for TBDs.

Objective

Our objective was to assess the knowledge, attitudes, and practices of Illinois clinicians towards ticks and TBDs. The study aimed to 1) identify predictors associated with knowledge, 2) identify knowledge gaps, and 3) evaluate attitudes and practices related to TBDs.

Methods

A web-based knowledge, attitudes, and practices survey about Illinois ticks and TBDs was disseminated to physicians, mid-level practitioners, and nurses between August 2020 and February 2022. Poisson regression analysis was conducted to identify predictors of higher scores.

Results

Of 346 respondents, 80% correctly identified Lyme disease as endemic to Illinois, and 95% were familiar with diagnostic testing for Lyme. Knowledge of other TBDs present in the state was highest among physicians, yet only 26% of physicians believed Rocky Mountain spotted fever (RMSF) to be present in Illinois, and only 17% believed ehrlichiosis to be endemic. Only 32% of physicians knew the cause of Alpha-gal syndrome and fewer than 18% were aware of available diagnostic testing. Tick or TBD-related education within the past two years was the most significant predictor of higher scores, increasing overall knowledge scores by 26% (RR 1.26, 95% CI 1.13-1.41) and increasing scores specific to TBDs by 42% (RR 1.42, 95% CI 1.19-1.69).

Conclusion

Illinois clinicians were informed about Lyme disease but lacked knowledge of other TBDs endemic to the state, including RMSF, ehrlichiosis, and Alpha-gal syndrome. The strongest predictor of knowledge was tick/TBD training in the previous two years, highlighting the importance of frequent region-specific training on ticks and TBDs.

Alpha-Gal Syndrome in the Infectious Diseases Clinic: A Series of 5 Cases in Central North Carolina

Background

Alpha-gal syndrome (AGS) is a recently described allergy to galactose-α-1,3-galactose, an oligosaccharide present in mammalian meat. AGS can present with angioedema, urticaria, and anaphylaxis arising 3-6 hours after ingestion, although symptoms such as gastrointestinal distress, fatigue, and arthralgias are also reported. Because AGS appears to be associated with tick bites, patients may present to infectious diseases (ID) clinics for evaluation.

Methods

We documented a series of 5 patients referred to the University of North Carolina ID Clinic between 2020 and 2022 for various tick-borne infections that were found to have symptoms and laboratory testing consistent with AGS. Patients were subsequently referred to the Allergy and Immunology Clinic.

Results

Patients were referred to the ID Clinic for persistent symptoms following positive tick-borne disease testing or presumed tick-borne infection. All patients had an elevated alpha-gal immunoglobulin E and clinical presentation consistent with AGS. Common symptoms included episodic gastrointestinal distress (eg, cramping, nausea, diarrhea), fatigue, arthralgias, and subjective cognitive impairment, but a notable absence of severe anaphylaxis. Four patients were seen by at least 1 nonallergy specialist prior to referral to ID. Patients reported substantial improvement in their symptoms following dietary restriction.

Conclusions

ID physicians should be aware of AGS as a cause of persistent, nonspecific symptoms following a tick exposure or tick-borne illness. Further research is needed to determine the prevalence of alpha-gal sensitization and AGS following tick-borne bites.

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.

The Meat of the Matter: Understanding and Managing Alpha-Gal Syndrome

Alpha-gal syndrome is an unconventional food allergy, characterized by IgE-mediated hypersensitivity responses to the glycan galactose-alpha-1,3-galactose (alpha-gal) and not to a food-protein. In this review, we discuss how alpha-gal syndrome reframes our current conception of the mechanisms of pathogenesis of food allergy. The development of alpha-gal IgE is associated with tick bites though the possibility of other parasites promoting sensitization to alpha-gal remains. We review the immune cell populations involved in the sensitization and effector phases of alpha-gal syndrome and describe the current understanding of why allergic responses to ingested alpha-gal can be delayed by several hours. We review the foundation of management in alpha-gal syndrome, namely avoidance, but also discuss the use of antihistamines, mast cell stabilizers, and the emerging role of complementary and alternative therapies, biological products, and oral immunotherapy in the management of this condition. Alpha-gal syndrome influences the safety and tolerability of medications and medical devices containing or derived from mammalian products and impacts quality of life well beyond food choices.

Cohort study of subclinical sensitization against galactose‐α‐1,3‐galactose in Japan: Prevalence and regional variations

Sensitization to galactose-α-1,3-galactose (α-Gal) leads to the development of α-Gal syndrome, which includes red meat allergy and cetuximab-induced anaphylaxis. Since tick bites represent the main cause of α-Gal sensitization, it was speculated that sensitization to α-Gal occurs throughout Japan. However, few cohort studies have investigated α-Gal sensitization in Japan. Therefore, we aimed to elucidate the subclinical sensitization rate to α-Gal in Japan. Sera were obtained from 300 participants without food or cetuximab allergy at Shimane University Hospital (Shimane prefecture), Tokyo Medical and Dental University Hospital (Tokyo metropolis), and Tohoku University Hospital (Miyagi prefecture). ImmunoCAP-bovine thyroglobulin (BTG), ImmunoCAP-beef, and IgE immunoblotting with cetuximab were performed to detect α-Gal-specific IgE. Clinical information was collected from participants using a questionnaire. The overall positivity rate of ImmunoCAP-BTG was 4.0% without significant inter-institute differences, whereas that for ImmunoCAP-beef was 9.7% with a significant inter-institute difference. Tokyo Medical and Dental University Hospital (19.0%) had the highest positivity rate. The positivity rate based on cetuximab IgE immunoblotting was 2.7%, without any significant inter-institute differences. The overall positivity rate for both ImmunoCAP-BTG and cetuximab immunoblotting was 2.0%, with a significant inter-institute difference; 5.0% of Shimane University Hospital was the highest. Two cases showed sensitization against the non-α-Gal epitope of cetuximab. The overall positivity rate for both ImmunoCAP-beef and cetuximab immunoblotting was 1.3%, without significant inter-institute differences. Male sex was associated with positive beef-specific IgE. The prevalence of subclinical sensitization to α-Gal is estimated at 2.0%-4.0% in Japan and may be higher in rural areas, supporting an association between tick bites and α-Gal sensitization. In contrast, the prevalence of subclinical sensitization to beef is 9.7% in Japan and is highest in Tokyo Metropolis, suggesting the presence of another IgE-binding epitope apart from α-Gal and another sensitization route in the sensitization to beef IgE.

Current and Future Strategies for the Diagnosis and Treatment of the Alpha-Gal Syndrome (AGS)

The α-Gal syndrome (AGS) is a pathognomonic immunoglobulin E (IgE)-mediated delayed anaphylaxis in foods containing the oligosaccharide galactose-α-1,3-galactose (α-Gal) such as mammalian meat or dairy products. Clinical presentation of AGS can also comprise immediate hypersensitivity due to anticancer therapy, gelatin-containing vaccines or mammalian serum-based antivenom. The IgE initial sensitization is caused by hard-bodied tick bites and symptomatic individuals typically develop delayed pruritus, urticaria, angioedema, anaphylaxis, malaise or gut-related symptoms. Due to inapparent presentation, delayed reactions and a wide variety of patients´ clinical history, the AGS diagnosis and treatment remain challenging. This review covers not only current diagnostic methods used for AGS such as the skin prick test (SPT), the oral food challenge (OFC), anti-α-Gal IgE levels measurement and the basophil activation test (BAT), but also potentially relevant next-generation diagnostic tools like the mast cell activation test (MAT), the histamine-release (HR) assay, omics technologies and model-based reasoning (MBR). Moreover, it focuses on the therapeutical medical and non-medical methods available and current research methods that are being applied in order to elucidate the molecular, physiological and immune mechanisms underlying this allergic disorder. Lastly, future treatment and preventive tools are also discussed, being of utmost importance for the identification of tick salivary molecules, with or without α-Gal modifications, that trigger IgE sensitivity as they could be the key for further vaccine development. Bearing in mind climate change, the tick-host paradigm will shift towards an increasing number of AGS cases in new regions worldwide, which will pose new challenges for clinicians in the future.

Adverse reactions to food: Navigating the maze in primary health care

Primary health care providers are often confronted with patients describing adverse reactions to food. With a multiplex of differential diagnoses, it is essential to have a structured approach to these complaints. Just as allergies can have a negative impact on quality of life, inappropriate food allergy labelling can cause unnecessary distress and hardship for patients. Understanding the diagnostic approaches to adverse food reactions, alongside an appreciation of multidisciplinary collaboration, can assist the clinician in making appropriate decisions in the management of these patients.

Diagnostic therapeutic care pathway for pediatric food allergies and intolerances in Italy: a joint position paper by the Italian Society for Pediatric Gastroenterology Hepatology and Nutrition (SIGENP) and the Italian Society for Pediatric Allergy and Immunology (SIAIP)

Epidemiologic data suggest an increased prevalence of pediatric food allergies and intolerances (FAIs) during the last decades. This changing scenario has led to an increase in the overall healthcare costs, due to a growing demand for diagnostic and treatment services. There is the need to establish Evidence-based practices for diagnostic and therapeutic intervention that could  be adopted in the context of public health policies for FAIs are needed.

This joint position paper has been prepared by a group of experts in pediatric gastroenterology, allergy and nutrition from the Italian Society for Pediatric Gastroenterology Hepatology and Nutrition (SIGENP) and the Italian Society for Pediatric Allergy and Immunology (SIAIP). The paper is focused on the Diagnostic Therapeutic Care Pathway (DTCP) for pediatric FAIs in Italy.

Adult anaphylaxis: A state-of-the-art review

Anaphylaxis is the most severe among acute allergic diseases and potentially life threatening. Despite its increasing frequency and related burden, it remains often underdiagnosed and improperly managed. Its multisystemic involvement, protean clinical manifestations and its rapid onset are contributory factors. In recent years new acquisitions have shed light into its pathogenesis pathways (and related biomarkers), triggers, factors increasing its severity, along with peculiar clinical manifestations. These breakthrough discoveries have contributed to phenotyping and endotyping this disease, possibly paving the way to a personalized approach which is not available at present. Moreover, to disseminate awareness and standardize diagnostic criteria and management practices, several guidelines and consensus reports, albeit mainly intended for specialist care, have been issued. We here discuss the latest issues in the field of anaphylaxis from the perspective of the emergency and/or internal medicine physician, so to improve its early recognition and treatment in the acute setting and favor allergology referral to implement therapeutical and preventive strategies, such as allergen identification in unclear cases and desensitizing therapies when available (e.g., for Hymenoptera venom allergy).

Meat Allergy: A Ticking Time Bomb

Food allergies are relatively prevalent, but mammalian meat allergy remains uncommon and represents an important, potentially acute healthcare risk. This risk is partly because both clinicians and the public lack awareness of this serious allergy, which is unique in three important ways: it incurs a delayed reaction, it is induced by a carbohydrate rather than a protein, and it is linked to tick bites. Although various symptoms are possible, its unique presentation means that mammalian meat allergy is often presented to the dermatologist. We review this challenging subject, which is particularly salient considering the unique connection between ticks and mammalian meat allergy, the expanding tick territory, and the dependency by so many on meat products, not only in the diet but also in medications and medical devices.

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

BACKGROUND

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.

OBJECTIVE

We analyzed and compared the in vitro allergenicity of α-Gal-carrying glycoproteins and glycolipids from natural food sources.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Clinical Issues-April 2022

Perioperative care of the patient with alpha-gal syndrome Key words: alpha-gal syndrome (AGS), red meat allergy, allergic reaction, mammalian-derived ingredients, gelatin. Overnight storage of sterile supplies Key words: sterile supplies, event-related sterility, terminal cleaning, damp dusting, instrument table. Unsterile medication cartridges Key words: dental cartridge, local anesthesia, lidocaine, alcohol, sterile field. Personnel traffic into the OR Key words: OR traffic, door openings, airflow, environmental contamination, automatic doors.

The Quantification of IgG Specific to α-Gal Could Be Used as a Risk Marker for Suffering Mammalian Meat Allergy

The alpha-Gal Syndrome is a delayed meat allergy characterized by the presence of sIgE against α-Gal epitope. It is known that the α-Gal present in tick saliva induces the sensitization to this epitope ending in the production of sIgG and sIgE to α-Gal. It could be considered that the more times a person is bitten by tick species, the higher the probability of making the switch from sIgG to sIgE to α-Gal and developing allergy, but it is no clear when the switch occurs. To determine the likelihood that a subject bitten by ticks but without AGS be at risk of developing this allergy, we quantified the levels of sIgG to α-Gal by an automated system (ImmunoCap). To stablish a cut-off value for sIgG to α-Gal, a receiving operating curve (ROC) was constructed. The statistical analysis demonstrated that the risk of suffering AGS in individuals bitten by ticks was 35% when the sIgG to α-Gal was greater than or equal to 40 µg/mL. Our data indicate that the sIgG values against α-Gal could be used as a prognostic marker for developing mammalian meat allergy.

Alpha-Gal Syndrome in Children: Peculiarities of a "Tick-Borne" Allergic Disease

The alpha-gal syndrome is an allergic syndrome that comprises two clinical pictures: an immediate hypersensitivity to drugs containing alpha-gal and a delayed hypersensitivity to the ingestion of red mammalian meat. This allergic syndrome is often under-recognized, and patients are mislabeled with diagnosis as spontaneous urticaria or idiopathic anaphylaxis. Even though less frequently, children could also be of interest, especially in tick-endemic areas. In most cases, a positive anamnesis for tick bites months before the onset of symptoms is recorded. The clinical manifestations could range from asymptomatic cases to severe anaphylaxis. The most frequently used diagnostic test is the determination of specific IgE for alpha-gal. Oral provocation test is usually reserved to unclear cases or to verify tolerance after diet. No long-term follow-up studies have been published, although an elimination diet could lead to a decrease of specific IgE for alpha-gal and a possible reintroduction of some avoided foods. This paper provides a literature review, focused on pediatric age, and an evaluation of available diagnostic tests. We analyze the correlation between tick bites and symptom onset and unfold the different clinical pictures to help clinicians to promptly recognized this syndrome. Lastly, we address unmet needs in this specific allergy.

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.

Demystifying α-gal syndrome: identification and risk management in the perioperative setting

PURPOSE OF REVIEW

α-Gal syndrome is among a vexing perioperative consideration for anesthesiologists. Commonly referred to as 'red meat allergy', α-Gal syndrome is precipitated by a lone star tick bite resulting in the formation of immunoglobulin E (IgE) antibodies against the tick salivary glycoproteins and noncatarrhine mammalian tissue.

RECENT FINDINGS

Up to 20% of the population in the southeastern United States may test positive for IgE antibodies to α-Gal. Increasingly, recognition of α-Gal syndrome as an immune response to red meat consumption and certain drugs, many of which may be administered within the perioperative period, has led to greater awareness of the insidious nature of its presentation - from mild urticaria and gastrointestinal symptoms to severe anaphylaxis.

SUMMARY

With the increasing prevalence and identification of α-Gal syndrome, a safe and tailored perioperative process is needed to integrate a pathway that involves multidisciplinary communication, robust information sharing platform, and a structured peri-procedure management.

Anaphylaxis: Epidemiology and Differential Diagnosis

Anaphylaxis-related emergency department (ED) visits and hospitalizations are increasing. Triggers for anaphylaxis include food, medications, and stinging insects. Idiopathic anaphylaxis accounts for 30% to 60% of cases of anaphylaxis in adults and up to 10% of cases in children with novel allergens such as galactose-α-1,3 galactose reclassifying these cases. Recent practice guidelines have recommended against the routine use of systemic corticosteroids and antihistamines for the prevention of biphasic reactions and recommend an extended observation, up to 6 hours, for those with risk factors for biphasic anaphylaxis and those with lack of access to epinephrine and to emergency medical services.

Biosynthesis of α-Gal Epitopes (Galα1-3Galβ1-4GlcNAc-R) and Their Unique Potential in Future α-Gal Therapies

The α-gal epitope is a carbohydrate antigen which appeared early in mammalian evolution and is synthesized in large amounts by the glycosylation enzyme α1,3galactosyltransferase (α1,3GT) in non-primate mammals, lemurs, and New-World monkeys. Ancestral Old-World monkeys and apes synthesizing α-gal epitopes underwent complete extinction 20–30 million years ago, and their mutated progeny lacking α-gal epitopes survived. Humans, apes, and Old-World monkeys which evolved from the surviving progeny lack α-gal epitopes and produce the natural anti-Gal antibody which binds specifically to α-gal epitopes. Because of this reciprocal distribution of the α-gal epitope and anti-Gal in mammals, transplantation of organs from non-primate mammals (e.g., pig xenografts) into Old-World monkeys or humans results in hyperacute rejection following anti-Gal binding to α-gal epitopes on xenograft cells. The in vivo immunocomplexing between anti-Gal and α-gal epitopes on molecules, pathogens, cells, or nanoparticles may be harnessed for development of novel immunotherapies (referred to as “α-gal therapies”) in various clinical settings because such immune complexes induce several beneficial immune processes. These immune processes include localized activation of the complement system which can destroy pathogens and generate chemotactic peptides that recruit antigen-presenting cells (APCs) such as macrophages and dendritic cells, targeting of antigens presenting α-gal epitopes for extensive uptake by APCs, and activation of recruited macrophages into pro-reparative macrophages. Some of the suggested α-gal therapies associated with these immune processes are as follows: 1. Increasing efficacy of enveloped-virus vaccines by synthesizing α-gal epitopes on vaccinating inactivated viruses, thereby targeting them for extensive uptake by APCs. 2. Conversion of autologous tumors into antitumor vaccines by expression of α-gal epitopes on tumor cell membranes. 3. Accelerating healing of external and internal injuries by α-gal nanoparticles which decrease the healing time and diminish scar formation. 4. Increasing anti-Gal–mediated protection against zoonotic viruses presenting α-gal epitopes and against protozoa, such as Trypanosoma, Leishmania, and Plasmodium, by vaccination for elevating production of the anti-Gal antibody. The efficacy and safety of these therapies were demonstrated in transgenic mice and pigs lacking α-gal epitopes and producing anti-Gal, raising the possibility that these α-gal therapies may be considered for further evaluation in clinical trials.

Alpha-gal syndrome: the first report in Poland

Alpha-gal syndrome is an immunoglobulin E (IgE)-dependent allergy to galactose-α-1,3-galactose, resulting in a delayed anaphylactic reaction to red meat. The syndrome is causally linked to bites from ticks and associated with cross-reactivity to some drugs, e.g. cetuximab. Although cases of alpha-gal allergy have already been reported in a few European countries, to our best knowledge, no cases have been reported so far in Central-Eastern Europe. In the current report, we describe a case of alpha-gal syndrome diagnosed in Poland, to highlight the fact that it may occur in new geographic areas. Within three months, the described patient underwent five anaphylactic reactions with typical clinical manifestations. They developed a few hours after ingestion of red meat (pork, beef or mutton) and were preceded by tick bites. The level of specific IgE antibodies to alpha-gal reached 72.6 kAU/l, whereas the levels of specific IgE antibodies to other food allergens were within the reference range. As the onset of symptoms in this syndrome is usually delayed, numerous cases may be identified as idiopathic anaphylaxis, while early diagnosis is indispensable to avoid potentially life-threatening complications.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Management of Tick-Borne Illness in the United States

The Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the prevention and management of tick-borne illness (TBI). Recommendations are graded based on quality of supporting evidence according to criteria put forth by the American College of Chest Physicians. The guidelines include a brief review of the clinical presentation, epidemiology, prevention, and management of TBI in the United States, with a primary focus on interventions that are appropriate for resource-limited settings. Strong recommendations are provided for the use of DEET, picaridin, and permethrin; tick checks; washing and drying clothing at high temperatures; mechanical tick removal within 36 h of attachment; single-dose doxycycline for high-risk Lyme disease exposures versus "watchful waiting;" evacuation from backcountry settings for symptomatic tick exposures; and TBI education programs. Weak recommendations are provided for the use of light-colored clothing; insect repellents other than DEET, picaridin, and permethrin; and showering after exposure to tick habitat. Weak recommendations are also provided against passive methods of tick removal, including the use of systemic and local treatments. There was insufficient evidence to support the use of long-sleeved clothing and the avoidance of tick habitat such as long grasses and leaf litter. Although there was sound evidence supporting Lyme disease vaccination, a grade was not offered as the vaccine is not currently available for use in the United States.

Successful Treatment for Alpha Gal Mammal Product Allergy Using Auricular Acupuncture: A Case Series

Introduction: Alpha gal syndrome (AGS) is an acquired allergy to mammalian products correlates with a tick bite(s) that appears to cause immune sensitization to an oligosaccharide in meat. Most publications on AGS describe no management other than avoidance of the offending agent(s). The objective of this study is to describe 2 populations of subjects who underwent Soliman Auricular Allergy Treatment (SAAT) for significant AGS meat and/or dairy allergy. Methods: We performed a retrospective review of subjects treated at 2 different medical clinics that apply the same method of auricular acupuncture (SAAT) to AGS patients. Results: A total of 137 patients presented to the 2 sites included in this study. The majority of patients were mammal product eaters before AGS; however, at the time of treatment only 7.3% of individuals (n = 10) actively consumed mammal products. Most subjects were reactive to beef (n = 135) and dairy (n = 95). The most common organ system involved in prior allergic reactions associated with AGS were gastrointestinal (n = 82, 59.9%) and dermatologic (n = 61, 44.5%). For those individuals with available outcome data on SAAT effectiveness (n = 126), 121 (96%) patients indicated that their symptoms were in remission after SAAT. Five individuals indicated that their symptoms were not in remission. Eleven individuals were unsure of treatment response or unable to be reached for follow-up. Conclusion: The SAAT method showed effectiveness in the large majority of patients. No adverse reactions were noted as a result of auricular acupuncture. This alternative medicine approach to AGS management should be further studied in prospective trials with laboratory confirmation both before and after the procedure. This low-risk treatment shows promise in treating a medical condition that causes distress in an increasing number of patients.

Allergy to Mammalian Meat Linked to Alpha-Gal Syndrome Potentially After Tick Bite in the Amazon: A Case Series

The past decade has seen the emergence of a new type of food allergy occurring after ingestion of mammalian meat. This allergy is related to immunoglobulin (Ig)E specific for galactose-alpha-1,3 galactose (α-Gal). Originally described in the United States in 2009, other cases have subsequently been described in Australia and in Europe, but still very few in Latin America. The purpose of this study was to show the existence of this pathology in French Guiana and to describe the historical, clinical, and biological characteristics of these patients. Patients reporting an allergy to mammalian meat were included between September 2017 and August 2019. Eleven patients were included, nine of whom exhibited digestive symptoms; four, urticaria reactions; three, respiratory reactions; and five angioedema. The time between ingestion of red meat and reaction varied between 1.5 and 6 hours. The implicated meats were most often beef and pork. All patients had been regularly exposed to tick bites before the appearance of symptoms. All the samples (n = 7) were positive for anti-α-Gal anti-mammalian meats IgE. All the patients were Caucasian French expatriates. This study confirms the presence of this new entity in French Guiana and is the largest reported in Latin America. Our results do not clearly allow us to state that tick bites are the cause of this allergy, but all patients reported being exposed regularly to these arthropods.

The expanding spectrum of disease caused by the Lone Star Tick, Amblyomma americanum

Ticks are remarkable vectors of a diverse and growing list of infectious agents of importance to both medical and veterinary disciplines. The tick Amblyomma americanum is one of the most frequently identified ticks in the United States with an expanding spectrum of human disease given its vast geographic range. The recently described Bourbon and Heartland viruses are likely transmitted by the Lone Star tick and are just two of the several novel tick-borne pathogens discovered in recent decades. The review will focus on these two viruses that can cause illness with similar characteristics to other diseases transmitted by the Lone Star tick. Healthcare professionals should consider these viruses in patients presenting with an ailment suggestive of a tick-born rickettsial disease that fails to improve with treatment with doxycycline. Additionally, some individuals may develop life-threatening allergic reactions triggered by the bite of the Lone Star tick.

Achieving Precision Medicine in Allergic Disease: Progress and Challenges

Allergic diseases (atopic dermatitis, food allergy, eosinophilic esophagitis, asthma and allergic rhinitis), perhaps more than many other traditionally grouped disorders, share several overlapping inflammatory pathways and risk factors, though we are still beginning to understand how the relevant patient and environmental factors uniquely shape each disease. Precision medicine is the concept of applying multiple levels of patient-specific data to tailor diagnoses and available treatments to the individual; ideally, a patient receives the right intervention at the right time, in order to maximize effectiveness but minimize morbidity, mortality and cost. While precision medicine in allergy is in its infancy, the recent success of biologics, development of tools focused on large data set integration and improved sampling methods are encouraging and demonstrates the utility of refining our understanding of allergic endotypes to improve therapies. Some of the biggest challenges to achieving precision medicine in allergy are characterizing allergic endotypes, understanding allergic multimorbidity relationships, contextualizing the impact of environmental exposures (the “exposome”) and ancestry/genetic risks, achieving actionable multi-omics integration, and using this information to develop adequately powered patient cohorts and refined clinical trials. In this paper, we highlight several recently developed tools and methods showing promise to realize the aspirational potential of precision medicine in allergic disease. We also outline current challenges, including exposome sampling and building the “knowledge network” with multi-omics integration.

Diseases Transmitted by the Black-Legged Ticks in the United States: A Comprehensive Review of the Literature

The black-legged tick is endemic to the midwestern, northeastern, western, south-eastern, and southern regions of the United States. There has been an increased burden of black-legged ticks in humans in recent years. COVID-19 pandemic has further heightened this burden. We thereby reviewed the literature to discuss the seasonality, infections, and clinical spectrum of diseases transmitted by the black-legged ticks. We also discuss the reported delay in the diagnosis of these diseases during the pandemic situation, the alpha-gal syndrome, the importance of prompt diagnosis, and early medical intervention with an aim to increase awareness of the black-legged tick-borne diseases.

Carbohydrate epitopes currently recognized as targets for IgE antibodies

Until recently, glycan epitopes have not been documented by the WHO/IUIS Allergen Nomenclature Sub-Committee. This was in part due to scarce or incomplete information on these oligosaccharides, but also due to the widely held opinion that IgE to these epitopes had little or no relevance to allergic symptoms. Most IgE-binding glycans recognized up to 2008 were considered to be "classical" cross-reactive carbohydrate determinants (CCD) that occur in insects, some helminths and throughout the plant kingdom. Since 2008, the prevailing opinion on lack of clinical relevance of IgE-binding glycans has been subject to a reevaluation. This was because IgE specific for the mammalian disaccharide galactose-alpha-1,3-galactose (alpha-gal) was identified as a cause of delayed anaphylaxis to mammalian meat in the United States, an observation that has been confirmed by allergists in many parts of the world. Several experimental studies have shown that oligosaccharides with one or more terminal alpha-gal epitopes can be attached as a hapten to many different mammalian proteins or lipids. The classical CCDs also behave like haptens since they can be expressed on proteins from multiple species. This is the explanation for extensive in vitro cross-reactivity related to CCDs. Because of these developments, the Allergen Nomenclature Sub-Committee recently decided to include glycans as potentially allergenic epitopes in an adjunct section of its website (www.allergen.org). In this article, the features of the main glycan groups known to be involved in IgE recognition are revisited, and their characteristic structural, functional, and clinical features are discussed.

Lessons in Innate and Allergic Immunity From Dust Mite Feces and Tick Bites

Allergic diseases represent a major cause of morbidity in modern industrialized and developing countries. The origins and development of allergic immune responses have proven difficult to unravel and remain an important scientific objective. House dust mites (HDM) and ticks represent two important causes of allergic disease. Investigations into HDM fecal particles and tick bites have revealed insights which have and will continue to shape our understanding of allergic immunity. In the present review, focus is given to the role of innate immunity in shaping the respective responses to HDM and ticks. The HDM fecal particle represents a rich milieu of molecules that can be recognized by pathogen-recognition receptors of the innate immune system. Factors in tick saliva and/or tissue damage resultant from tick feeding are thought to activate innate immune signaling that promotes allergic pathways. Recent evidence indicates that innate sensing involves not only the direct recognition of allergenic agents/organisms, but also indirect sensing of epithelial barrier disruption. Although fecal particles from HDM and bites from ticks represent two distinct causes of sensitization, both involve a complex array of molecules that contribute to an innate response. Identification of specific molecules will inform our understanding of the mechanisms that contribute to allergic immunity, however the key may lie in the combination of molecules delivered to specific sites in the body.

Nationwide pharmacovigilance data for cetuximab-induced anaphylaxis and predictive model validation using prospective specific IgE detection

Background

Cetuximab (chimeric monoclonal antibody to human epidermal growth factor receptor) is used to treat colorectal and head and neck cancers. Due to cross-reactivity with galactose-α-1,3-galactose (alpha-gal), it can induce hypersensitivity even at first administration. We aimed to determine the incidence and clinical manifestation of cetuximab-induced anaphylaxis, and to establish a means of predicting its incidence in patients ahead of treatment.

Methods

Nationwide and single-center pharmacovigilance data from 2010 to 2017 were collected from the Korea Institute of Drug Safety-Korea Adverse Event Reporting System and Severance Regional Pharmacovigilance Center. Patients scheduled for cetuximab administration were enrolled prospectively. A skin prick test was carried out and serum IgE specific to cetuximab and cross-reactive allergens were measured. Reactions were monitored after cetuximab infusion.

Results

Over 8 years, there were 23 reports of anaphylaxis nationwide. In a single-center study, incidence of cetuximab-induced anaphylaxis was 1.1%. Most anaphylaxis occurred at first injection (93.3%), even under pretreatment with anti-allergic drugs. Four of 64 patients (6.3%) experienced severe anaphylaxis. The median cetuximab-specific IgE titer was 6.9 kU_A/L in patients experiencing anaphylaxis and 0 kU_A/L in those who did not (P < 0.001). The results of alpha-gal, beef sIgE, and cetuximab skin prick testing were similar to those of cetuximab sIgE. Patients who did not experience hypersensitivity were negative in all 4 allergy tests. Its positive and negative predictive values were 100%.

Conclusions

Specific IgE detection of cetuximab or alpha-gal can accurately predict cetuximab-induced anaphylaxis prior to first administration.

Treatment Approaches to Food Allergy

IgE-mediated food allergies affect both children and adults and are associated with dramatic decreases in the quality of life. In the majority of cases, food allergens have to be avoided which may be difficult, particularly in patients who suffer from life-threatening symptoms following the ingestion of minimal doses of food allergens. Several novel therapeutic approaches have been studied during the recent past and are summarized in this review. Therapies with novel therapeutic monoclonal antibodies, innovative allergen-specific immunotherapies using subcutaneous, sublingual, or epicutaneous routes, and oral immunotherapies leading to increases of individual thresholds of tolerable foods upon their continuous ingestion showed promising results which may change future management strategies in moderate to severe food allergy.

Food Allergy: Catering for the Needs of the Clinician

The practice of food allergy (FA) for clinicians has boomed, with a dramatic rise in the number of patients and families seeking care and with many advances on several fronts. The practice itself sometimes is evidence-based science and sometimes an art of pattern and phenotype recognition. This article examines the tools for diagnosis and management and therapy options available to physicians providing care for patients with FA. The article touches on pressing needs of clinicians and highlights the rapid and important movements in national and international support and advances that will have a positive impact on the field of FA.

Alpha-Gal Allergy as a Cause of Intestinal Symptoms in a Gastroenterology Community Practice

OBJECTIVES

Immunoglobulin E (IgE) to galactose-α-1,3-galactose (alpha-gal) is a recently appreciated cause of allergic reactions to mammalian meat and dairy. In eastern North America Lone Star tick bites are the dominant mode of sensitization. Classically the alpha-gal syndrome manifests with urticaria, gastrointestinal symptoms, and/or anaphylaxis, but increasingly there are reports of isolated gastrointestinal symptoms without other common allergic manifestations. The objective of this retrospective study was to determine the frequency of IgE to alpha-gal in patients presenting with unexplained gastrointestinal symptoms to a community gastroenterology practice, and to evaluate the symptom response to the removal of mammalian products from the diet in alpha-gal-positive individuals.

METHODS

An electronic medical record database was used to identify patients with alpha-gal IgE laboratory testing performed within the past 4 years. These charts were reviewed for alpha-gal test results, abdominal pain, diarrhea, nausea and vomiting, hives, bronchospasm, diagnosis of irritable bowel syndrome, postprandial exacerbation of symptoms, meat exacerbation of symptoms, patient recall of tick bite, other simultaneous gastrointestinal tract diagnoses, and clinical improvement with mammalian food product avoidance.

RESULTS

A total of 1112 adult patients underwent alpha-gal IgE testing and 359 (32.3%) were positive. Gastrointestinal symptoms were similar in those positive and negative for alpha-gal seroreactivity. Of the 359 alpha-gal-positive patients, 122 had follow-up data available and 82.0% of these improved on a diet free of mammalian products. Few patients reported hives (3.9%) or bronchospasm (2.2%). Serum alpha-gal IgE titers ranged from 0.1 to >100 kU/L, with an average of 3.43 kU/L and a median of 0.94 kU/L.

CONCLUSIONS

Clinicians practicing in the region of the Lone Star tick habitat need to be aware that patients with IgE to alpha-gal can manifest with isolated abdominal pain and diarrhea, and these patients respond well to dietary exclusion of mammalian products.

'Doc, will I ever eat steak again?': diagnosis and management of alpha-gal syndrome

PURPOSE OF REVIEW

Alpha-gal syndrome encompasses a constellation of symptoms associated with immune-mediated hypersensitivity responses to galactose-alpha-1,3-galactose (alpha-gal). The purpose of this review is to discuss our current understanding of the etiology, clinical symptoms, natural history, epidemiology, and management of alpha-gal syndrome.

RECENT FINDINGS

Sensitization to alpha-gal is associated with bites from ectoparasites like the lone star tick Amblyomma americanum. Allergic reactions in alpha-gal syndrome are often delayed and inconsistent. The magnitude of the allergic response depends on co-factors like exercise and alcohol consumption and the amount of alpha-gal and fat present in the food. Assaying alpha-gal-specific IgE in the serum is the primary diagnostic test used to confirm the allergy. Long-term management of the condition involves avoidance of both mammalian food products and tick bites.

SUMMARY

Alpha-gal syndrome disrupts the current paradigm for understanding food allergy. Exposure to an ectoparasite is critical for the development of specific IgE antibodies underlying sensitization, and allergic reactions depend on the activation of mast cells and basophils sensitized with IgE against a carbohydrate rather than a protein. Research in this field may lead to the development of improved diagnostic and therapeutic tools that can revolutionize the management of patients with alpha-gal syndrome.

World allergy organization anaphylaxis guidance 2020

Anaphylaxis is the most severe clinical presentation of acute systemic allergic reactions. The occurrence of anaphylaxis has increased in recent years, and subsequently, there is a need to continue disseminating knowledge on the diagnosis and management, so every healthcare professional is prepared to deal with such emergencies. The rationale of this updated position document is the need to keep guidance aligned with the current state of the art of knowledge in anaphylaxis management. The World Allergy Organization (WAO) anaphylaxis guidelines were published in 2011, and the current guidance adopts their major indications, incorporating some novel changes. Intramuscular epinephrine (adrenaline) continues to be the first-line treatment for anaphylaxis. Nevertheless, its use remains suboptimal. After an anaphylaxis occurrence, patients should be referred to a specialist to assess the potential cause and to be educated on prevention of recurrences and self-management. The limited availability of epinephrine auto-injectors remains a major problem in many countries, as well as their affordability for some patients.

Diagnosis and management of anaphylaxis

Anaphylaxis is a serious allergic reaction that is rapid in onset and may be life threatening. An informal review of the literature was performed in a nonsystematic way for this article. Key published work was identified and included. The incidence and prevalence of anaphylaxis have increased over time. Anaphylaxis is unpredictable and can be the result of various allergic triggers, including food, insect venom, and medication. In children, the most frequent trigger is food. The diagnosis is based on clinical criteria. After confirmation of the relevant allergen trigger, prevention occurs through strict avoidance of the allergen and optimal management of existing comorbidities. Patients with anaphylaxis require immediate assessment and treatment. The management of a patient with anaphylaxis should start with the removal of exposure to the known or suspected trigger, followed by the assessment of the patient's circulation, airway patency, breathing, and mental status. The administration of epinephrine at a dose of 0.01 mg/kg (1:1000) intramuscularly is the first-line treatment for anaphylaxis, and there are no absolute contraindications to this treatment. The maximum single dose of epinephrine is 0.5 mg and may be repeated after 5-10 minutes if needed. After administration of epinephrine, patients with anaphylaxis should be placed supine with their lower limbs elevated. They should not be placed in the upright position. Studies of fatal and near-fatal allergic reactions identified potential risk factors for fatalities such as asthma, peanuts and/or tree nuts, and delayed epinephrine use, and provided important information that may help minimize the future risk. Patients and their families need to be well educated on how to manage potential anaphylactic reactions with training in the use of epinephrine autoinjectors and personalized emergency management plans. Health care professionals must be familiar with this clinical emergency and able to respond to anaphylaxis in a timely and appropriate manner.

Galactose-alpha-1,3-galactose syndrome

The galactose-alpha-1,3-galactose (alpha-Gal) syndrome is a newly recognized and unique form of food allergy, characterized by delayed reactions to mammalian meats. This form of allergy occurs in individuals who become sensitized to alpha-Gal, a carbohydrate that is present on most mammalian tissues. Sensitization occurs after exposure to multiple arthropod bites, most commonly the lone star tick. Cases of the alpha-Gal syndrome are primarily found in the southeastern United States, which overlaps with the known geographic distribution of the lone star tick. Patients present with a history of delayed symptom onset, ~2-6 hours after ingestion of mammalian meat. As with other immunoglobulin E (IgE) mediated food allergic reactions, alpha-Gal reaction symptoms may include skin, respiratory, gastrointestinal, or cardiovascular systems, and severity may range from mild reactions to severe anaphylaxis. The diagnosis is based on the detection of alpha-Gal specific IgE (sIgE) as well as the total IgE value because some cases include patients with low total IgE levels but a high percentage of alpha-Gal sIgE to total serum IgE levels. Percutaneous testing with commercial meat skin-prick testing extracts is not a reliable tool for diagnosis. Prick-prick skin testing to fresh cooked meat may be considered, whereas intradermal testing to fresh meat is primarily reserved for research purposes. The mainstay of treatment involves avoidance of mammalian meat and medications that express the same carbohydrate antigen. With a small portion of patients, other meat-containing products should also be avoided if symptoms persist with mammalian meat avoidance alone. Prolonged avoidance of mammalian meat as well as avoidance of further tick bites can decrease alpha-Gal sIgE over time, and some patients are able to reintroduce mammalian meat into their diet.

B Cell Responses in the Development of Mammalian Meat Allergy

Studies of meat allergic patients have shown that eating meat poses a serious acute health risk that can induce severe cutaneous, gastrointestinal, and respiratory reactions. Allergic reactions in affected individuals following meat consumption are mediated predominantly by IgE antibodies specific for galactose-α-1,3-galactose (α-gal), a blood group antigen of non-primate mammals and therefore present in dietary meat. α-gal is also found within certain tick species and tick bites are strongly linked to meat allergy. Thus, it is thought that exposure to tick bites promotes cutaneous sensitization to tick antigens such as α-gal, leading to the development of IgE-mediated meat allergy. The underlying immune mechanisms by which skin exposure to ticks leads to the production of α-gal-specific IgE are poorly understood and are key to identifying novel treatments for this disease. In this review, we summarize the evidence of cutaneous exposure to tick bites and the development of mammalian meat allergy. We then provide recent insights into the role of B cells in IgE production in human patients with mammalian meat allergy and in a novel mouse model of meat allergy. Finally, we discuss existing data more generally focused on tick-mediated immunomodulation, and highlight possible mechanisms for how cutaneous exposure to tick bites might affect B cell responses in the skin and gut that contribute to loss of oral tolerance.

Red Meat Allergies after Lone Star Tick (Amblyomma americanum) Bites

Red meat allergies have followed tick bites on every continent except Antarctica. The sensitizing antigen is galactose-α-1,3-galactose (α-gal), an oligosaccharide constituent of nonprimate blood and meat, acquired by ticks during animal bloodfeeding. Because red meat allergy after tick bites is a worldwide phenomenon, the objectives of this review were to describe the global epidemiology of red meat allergy after tick bites and its immunological mechanisms; to identify the human risk factors for red meat allergy after tick bites; to identify the most common tick vectors of red meat allergy worldwide; to describe the clinical manifestations, diagnostic confirmation, and management of patients with red meat allergy after tick bites; and to recommend strategies for the prevention of tick bites. To meet these objectives, Internet search engines were queried with keywords to select scientific articles for review. The keywords included ticks, tick bites, allergy, anaphylaxis, and meat allergy. The study period was defined as 1980-2019. The major risk factors for red meat allergy after tick bites included male sex, non-B blood type, systemic mastocytosis, a bioprosthetic (bovine or porcine) heart valve, and preexisting allergies to gelatin or animal dander. Following confirmation by challenge testing, patients with red meat allergies should avoid red meats, foods containing gelatin, and intravenous immunotherapy with monoclonal antibodies such as cetuximab and infliximab produced in SP2/0 mouse cell lines. Red meat allergy after tick bites represents an emerging threat from tick bites in addition to infectious diseases.

The Possible Role of Anti-Neu5Gc as an Obstacle in Xenotransplantation

Seventy to ninety percentage of preformed xenoreactive antibodies in human serum bind to the galactose-α(1,3)-galactose Gal epitope, and the creation of Gal knockout (KO) pigs has eliminated hyperacute rejection as a barrier to xenotransplantation. Now other glycan antigens are barriers to move ahead with xenotransplantation, and the N-glycolyl neuraminic acid, Neu5Gc (or Hanganutziu-Deicher antigen), is also a major pig xenoantigen. Humans have anti-Neu5Gc antibodies. Several data indicate a strong immunogenicity of Neu5Gc in humans that may contribute to an important part in antibody-dependent injury to pig xenografts. Pig islets express Neu5Gc, which reacted with diet-derived human antibodies and mice deleted for Neu5Gc reject pancreatic islets from wild-type counterpart. However, Neu5Gc positive heart were not rejected in Neu5Gc KO mice indicating that the role of Neu5Gc-specific antibodies has to be nuanced and depend of the graft situation parameters (organ/tissue, recipient, implication of other glycan antigens). Recently generated Gal/Neu5Gc KO pigs eliminate the expression of Gal and Neu5Gc, and improve the crossmatch of humans with the pig. This review summarizes the current and recent experimental and (pre)clinical data on the Neu5Gc immunogenicity and emphasize of the potential impact of anti-Neu5Gc antibodies in limiting xenotransplantation in humans.

On the cause and consequences of IgE to galactose-α-1,3-galactose: A report from the National Institute of Allergy and Infectious Diseases Workshop on Understanding IgE-Mediated Mammalian Meat Allergy

The mammalian meat allergy known as the "α-Gal syndrome" relates to IgE specific for galactose-α-1,3-galactose (α-Gal), an oligosaccharide that is present in cells and tissues of nonprimate mammals. The recognition of delayed reactions to food derived from mammals in patients with IgE to α-Gal and also the association with tick bites have been increasing worldwide. In 2018, the National Institute of Allergy and Infectious Diseases, Division of Allergy, Immunology and Transplantation, sponsored a workshop on this emerging tick-related disease. International experts from the fields of tick biology, allergy, immunology, infectious disease, and dermatology discussed the current state of our understanding of this emerging medical condition. The participants provided suggestions for specific research priorities and for the development of resources to advance our knowledge of the mechanisms, diagnosis, management, and prevention of this allergic disease. This publication is a summary of the workshop and the panel's recommendations are presented herein.