Anaphylactic reaction in patient allergic to mango

Food-Pollen Cross-Reactivity and its Molecular Diagnosis in China

PURPOSE OF REVIEW

Plant-derived foods are one of the most common causative sources of food allergy in China, with a significant relationship to pollinosis. This review aims to provide a comprehensive overview of this food-pollen allergy syndrome and its molecular allergen diagnosis to better understand the cross-reactive basis.

RECENT FINDINGS

Food-pollen cross-reactivity has been mainly reported in Northern China, Artemisia pollen is the major related inhalant source, followed by tree pollen (Betula), while grass pollen plays a minor role. Pollen allergy is relatively low in Southern China, with allergies to grass pollen being more important than weed and tree pollens. Rosaceae fruits and legume seeds stand out as major related allergenic foods. Non-specific lipid transfer protein (nsLTP) has been found to be the most clinically relevant cross-reacting allergenic component, able to induce severe reactions. PR-10, profilin, defensin, chitinase, and gibberellin-regulated proteins are other important cross-reactive allergen molecules. Artemisia pollen can induce allergenic cross-reactions with a wide range of plant-derived foods in China, and spring tree pollens (Betula) are also important. nsLTP found in both pollen and plant-derived food is considered the most significant allergen in food pollen cross-reactivity. Component-resolved diagnosis with potential allergenic proteins is recommended to improve diagnostic accuracy and predict the potential risk of causing allergic symptoms.

New light on an old syndrome: Role of Api g 7 in mugwort pollen-related celery allergy

BACKGROUND

Celery root is known to cause severe allergic reactions in patients sensitized to mugwort pollen.

OBJECTIVE

We studied clinically well-characterized patients with celery allergy by IgE testing with a comprehensive panel of celery allergens to disentangle the molecular basis of what is known as the celery-mugwort syndrome.

METHODS

Patients with suspected food allergy to celery underwent a standardized interview. Main inclusion criteria were a positive food challenge with celery or an unambiguous case history of severe anaphylaxis. IgE to celery allergens (rApi g 1.01, rApi g 1.02, rApi g 2, rApi g 4, nApi g 5, rApi g 6, rApi g 7) and to mugwort allergens (rArt v 1, rArt v 3, rArt v 4) were determined. IgE levels ≥0.35 kUA/L were regarded positive.

RESULTS

Seventy-nine patients with allergy to celery were included. Thirty patients had mild oral or rhinoconjunctival symptoms, and 49 had systemic reactions. Sixty-eight percent had IgE to celery extract, 80% to birch pollen, and 77% to mugwort pollen. A combination of Api g 1.01, 1.02, 4, 5, and 7 increased the diagnostic sensitivity for celery allergy to 92%. The lipid transfer proteins Api g 2 and Api g 6 were not relevant in our celery-allergic population. IgE to Api g 7, detected in 52% of patients, correlated closely (r = 0.86) to Art v 1 from mugwort pollen. Eleven of 12 patients with monosensitization to Api g 7 were IgE negative to celery extract. The odds ratio for developing a severe anaphylactic reaction rather than only mild oral symptoms was about 6 times greater (odds ratio, 5.87; 95% confidence interval, 1.08-32.0; P = .0410) for Api g 7-sensitized versus -nonsensitized subjects.

CONCLUSION

There is an urgent need for routine diagnostic tests to assess sensitization to Api g 7, not only to increase test sensitivity but also to identify patients at risk of a severe allergic reaction to celery.

The use of inhibition assay in Api g 7 suspected allergy in a female patient with anaphylaxis: A case report

The symptoms of celery allergy are mainly presented as oral allergy symptom, but there are several case reports of patients who experienced anaphylaxis. Defensin (Api g 7), as a novel allergen in celery root, was described in 2022 r. The female patient had a history of several episodes of dyspnea and cough, associated with ingestion of spice mixes containing dried celery. Up to the point of hospitalization, there were no objective tests, either sIgE or skin prick tests, that would confirm celery sensitization. During hospitalization, patient had a positive double-blind placebo-controlled food challenge with cooked celery. The patient was sensitized to mugwort defensin Art v 1. An inhibition assay with celery allergen extract was performed to prove cross-sensitization between Art v 1 and celery allergen responsible for symptoms in the patient. In conclusion, Api g 7 is an important celery allergen that can be responsible for severe reactions. Its cross-reactivity with Art v 1 is characteristic. Negative diagnostic tests with celery do not exclude Api g 7 sensitization.

The Role of Defensins as Pollen and Food Allergens

PURPOSE OF REVIEW

Defensin-polyproline-linked proteins are relevant allergens in Asteraceae pollen. Depending on their prevalence and amount in the pollen source, they are potent allergens, as shown for the major mugwort pollen allergen Art v 1. Only a few allergenic defensins have been identified in plant foods, such as peanut and celery. This review provides an overview of structural and immunological features, IgE cross-reactivity, and diagnostic and therapeutic options regarding allergenic defensins.

RECENT FINDINGS

We present and critically review the allergenic relevance of pollen and food defensins. The recently identified Api g 7 from celeriac and other allergens potentially involved in Artemisia pollen-related food allergies are discussed and related to clinical severity and allergen stability. To specify Artemisia pollen-related food allergies, we propose the term "defensin-related food allergies" to account for defensin-polyproline-linked protein-associated food syndromes. There is increasing evidence that defensins are the causative molecules in several mugwort pollen-associated food allergies. A small number of studies have shown IgE cross-reactivity of Art v 1 with celeriac, horse chestnut, mango, and sunflower seed defensins, while the underlying allergenic molecule remains unknown in other mugwort pollen-associated food allergies. As these food allergies can cause severe allergic reactions, identification of allergenic food defensins and further clinical studies with larger patient cohorts are required. This will allow molecule-based allergy diagnosis and a better understanding of defensin-related food allergies to raise awareness of potentially severe food allergies due to primary sensitization to Artemisia pollen.

Clinical Use of the ImmunoCAP Inhibition Test in the Diagnosis of Meat Allergy Caused by a Tick Bite in an Adult Male with No Previous Atopic History

(1) Background: alpha-gal syndrome (AGS) is a serious, potentially life-threatening allergic reaction. This is a type of food allergy to red meat and other mammalian products (e.g., gelatin). In Poland, this problem seems to be rare or, more likely, very underdiagnosed. The diagnosis of AGS is difficult. It seems that the knowledge about this syndrome is insufficient. There are no effective diagnostic tools able to clearly diagnose this cross-reactive allergy. This paper presents the clinical application of a non-standard method in the diagnosis of a cross-reactive allergy using the example of AGS. (2) Methods: standard tests for in vitro allergy diagnostics and the non-standard ImmunoCAP inhibition test(IT) were carried out for serum collected from a patient with a red meat allergy. (3) Results: the serum concentration of anti-α-Gal IgE was very high (302 kUA/L), and IgE antibodies toanti-mammalian-meat allergens were found. The level of IgE antibodies to mammalian meat allergens decreased after blocking on α-GAL-CAP. The concentration of anti-α-Gal IgE decreased after blocking on CAPs coated with various mammalian meat allergens. Blocking with allergens of poultry meat did not affect the concentration of anti-α-Gal IgE. (4) Conclusions: the ImmunoCAP ITseems to be a useful tool in the diagnosis of cross-reactive allergies. Based on their clinical history and test results, the patient was diagnosed with AGS caused by a primary sensitization to α-Gal after a tick bite. This is the second case of AGS described in Poland and the first in Pomerania.

The Two-Sided Experimental Model of ImmunoCAP Inhibition Test as a Useful Tool for the Examination of Allergens Cross-Reactivity on the Example of α-Gal and Mammalian Meat Sensitization-A Preliminary Study

Cross-reactivity of allergens is the cause of various, sometimes unexpected, clinical reactions. There are no standard methods to investigate cross-reactivity. We present an experimental model of a two-sided inhibition test (IT) on ImmunoCAP membranes (CAP). We constructed the described model based on the known cross-allergy syndrome to red meat developing in people bitten by ticks (α-Gal syndrome; AGS). Some individuals who are bitten by ticks develop IgE antibodies specific to the carbohydrate determinant, galactose-α-1,3-galactose (α-Gal), present in the tick's saliva. These antibodies can cross-react with α-Gal molecules expressed on mammalian meat proteins. The well-known property of anti-α-Gal IgE antibodies binding by various sources of this allergen was used by us in the proposed model of the two-sided inhibition test on ImmunoCAP membranes. We expected that anti-α-Gal IgE antibodies bind allergens from mammalian meat and blocking them abolishes this reactivity, and the two-sided inhibition test model we proposed on ImmunoCAP membranes allowed us to observe such a relationship. We conducted the experiment three times on biological material from people with different clinical manifestations of allergy to α-Gal, each time obtaining similar results. In conclusion, the model of bilateral inhibition on ImmunoCAP membranes proposed by us seems to be an attractive, simple tool for direct testing of allergic cross-reactivity.

Experimental Research Models to Assess the Cross-Reactivity between Can f 5 and Human PSA—Two Different Perspectives

The similarity in antigenic structures, including the degree of correspondence between the amino acid sequence and the spatial structure, is not always reflected in the actual cross-reactivity of allergens. Inhibition tests appear to be an invaluable tool for assessing potential cross-reactivity between allergens under natural conditions. In this publication, we present two experimental models of inhibition tests: solid phase (SP-IT) and liquid phase (LP-IT). As an exemplary research model, we used the cross-reactivity between human PSA and anti-Can f 5 IgE antibodies. We performed an SP-IT model using a microplate coated with human PSA. The LP-IT model was based on mixing anti-Can f 5 IgE positive serum with a material containing human PSA. Anti-Can f 5 IgE and PSA concentrations before and after inhibition were measured to evaluate inhibition effectiveness. The results of the performed experiments showed that both proposed models of inhibition tests are an effective tools for studying cross-reactive relationships between antigens. In the SP-IT, the concentration of anti-Can f 5 decreased by 21.6% and, in the LP-IT, it decreased by 34.51%. In turn, the PSA concentration in the SP-IT decreased by 11.25% and, in the LP-IT, it decreased by 15.49%. In conclusion, both the SP-IT and the LP-IT seem to be effective tools for assessing the actual cross-reactivity between different allergens.

Prevalence, clinical presentation, and associated atopic diseases of pediatric fruit and vegetable allergy: A population-based study

BACKGROUND

In children, fruit and vegetable allergies are often overlooked compared with well-known allergies such as those to eggs, milk, and shellfish. Therefore, this study aimed to analyze fruit and vegetable allergies in children, including prevalence, types of food allergens, clinical presentation, management, and associated comorbid atopic diseases.

METHODS

In 2012, a nationwide, cross-sectional, random sampling questionnaire-based survey for common fruit and vegetable allergies was conducted in Taiwan. Information regarding these plant food allergies was collected. Physicians diagnosed food allergies according to the descriptions of convincing symptoms. Enrolled questionnaires were reviewed by expert pediatricians.

RESULTS

A total of 9,982 valid questionnaires were analyzed. The overall prevalence of fruit and vegetable allergies was 5.6% (n = 560) and 3.0% (n = 304), respectively. The most common fruit allergen was mango, followed by kiwifruit, whereas taro and bamboo shoot were the most common vegetable allergens. Meanwhile, most allergic symptoms were of the mucocutaneous tissue, followed by the upper airway and gastrointestinal tract. Most only required avoidance of allergens and not medical treatment. Children with fruit or vegetable allergies had a higher percentage of comorbid atopic dermatitis, allergic rhinitis, and asthma than those without food allergies; additionally, the proportion of comorbid atopic diseases was similar between fruit and vegetable allergies and shellfish allergy. One child developed anaphylaxis due to a corn allergy.

CONCLUSIONS

Fruits and vegetables are common food allergens in Taiwanese children who present with diverse and potentially severe symptoms. Children with plant food allergies had a percentage of comorbid atopic diseases similar to that of shellfish allergy, the most common allergen. These findings indicate the importance of considering fruit and vegetable allergies in children.

Contact Allergy Induced by Mango (Mangifera indica): A Relevant Topic?

Introduction: The most common clinical manifestation of mango allergy is contact dermatitis, which can be localized or systemic. The sensitising substances that have long been suspected are alk(en)yl catechols and/or alk(en)yl resorcinols. Methods: We reviewed the original articles published on Pubmed, Embase and Cochrane Library before 15 September 2021, on the topic of contact allergy induced by mango and we synthesized the key data. Results: We found 12 case reports and four case series, with a total of 37 patients. Only seven of these cases were reported in patients from mango-cultivating countries, the other 30 were from countries where mango cultivation does not occur, and 26 were also from countries where poison ivy/oak are commonly found. We found that contact dermatitis may occur on the first exposure to mango due to previous sensitisation to urushiol-containing plants. The diagnosis was confirmed by patch testing in some of the cases. There was great heterogeneity between the reagents used. Conclusion: Mango fruit is frequently consumed, but mango induced contact dermatitis, the main hypersensitivity reaction induced by mango, is rare. Further data is necessary for a better understanding of sensitising substances and, consecutively, standardization of patch test reagents.

Analysis of allergen profile in patients sensitized to canine allergen and potential Can f 5 cross-reactivity with human PSA

Can f 5 allergy and possible cross-reactivity with human semen in which there are significant amounts of prostate-specific antigen (PSA) are particularly interesting aspects of allergy to dog. The objective of the study was to confirm cross-reactivity between human PSA and Can f 5 in a study of canine sensitised women. A total of 100 women (aged 18-73, 41 on average) with a positive history of animal fur allergy or positive skin prick tests to canine allergens were selected. Levels of Immunoglobulin E (IgE) specific to Can f 1, Can f 2, Can f 3, Can f 5 were determined. Patients with increased concentration of sIgE Can f 5 were selected for further inhibition testing using polystyrene microplate ELISA test coated with human PSA. In the studied population, allergy to Can f 5 dominated (52.3% of patients with increased concentration of canine-specific IgE were allergic to this allergenic component). In all analyzed cases, the concentration of IgE Can f 5 decreased after incubation on the ELISA plate coated with human PSA. The minimum decrease in concentration was 10.44%, the maximum was 37.73%, the average decrease was 21.6%. No statistically significant influence of the presence or absence of allergenic sIgE Can f 5 in blood serum on the occurrence of symptoms after intercourse was found. The study confirmed the moderate ability of Can f 5 to cross-react with human PSA sIgE, which may be clinically significant in some women. At the same time, symptoms of an allergy to male semen do not constitute a typical clinical presentation of allergy to Can f 5.