Background:
An allergy to mango is extremely rare. The antigenic composition of the fruit is not fully known. Profilin from mango has a structure similar to birch tree profiling: it is responsible for cross-reactions between mango and pear, apple, and peach. A panallergen with a structure similar to mugwort defensin (Art v 1) which cross-reacts with celery, carrot, peanuts, pepper, aniseed, and caraway has been previously described.
Case study:
A female patient, 30 years old, was admitted in February 2017 because of recurrent allergic reactions following consumption of various foods. The most severe allergic reaction in the patient's life occurred after eating a mango fruit. Within several minutes the patient developed a generalised urticaria, followed by facial oedema, strong stomach pain and watery diarrhoea. The diagnostics involved skin tests with a set of inhalatory and food allergens, including native skin tests. The patient also experienced symptoms of recurrent, generalized urticaria in connection with consumption of various types of food, especially complex dishes containing many different ingredients. Additionally, an interview revealed that the patient was experiencing symptoms of the oral allergy syndrome after ingesting various fruit and vegetables, especially during late summer and fall. Diagnostics was extended by determining the levels of IgE specific for allergen components, using the ImmunoCap ISAC method. In order to confirm the occurence of a cross-reaction between mugwort and mango allergens, we performed the inhibition test of IgE specific for mugwort using a mango allergen extract and ImmunoCap matrix.
Results:
Skin prick tests (SPT) were positive for allergens of grass 7 mm; weeds 8 mm; cat's fur 5 mm; mugwort 6 mm. SPT were also positive for mango. The level of specific IgE was increased for allergens of mugwort, grass, celery, pepper, carrot, mango, banana, peach, and apple. The ImmunoCap ISAC test demonstrated a high level of specific IgE rPhl p 1 (timothy grass) and Art v 1 (mugwort). We also performed the IgE inhibition test using both mango extract and ImmunoCap matrix and confirmed a cross-reaction with Art v 1 in the pathogenesis of symptoms observed in the patient.
Conclusions:
An anaphylactic reaction to consumed mango, resulting from cross-allergy with mugwort Art v 1 was diagnosed in the patient. Acute urticarial in this case is a manifestation of IgE-mediated food allergy. During in vitro diagnostic procedures we found an elevated concentration of IgE specific to several food allergens (including celery, peppers, carrot, banana, peach, apple, shrimp). The elimination diet removing allergens the patient was allergic to was recommended. Considering the anaphylactic reaction the patient was instructed to carry a rescue set composed of an adrenaline autosyringe, steroids, and antihistamines.