D1.278 - Dragon fruit Allergy: A Case of Cross-Reactivity and Dietary Risks

Dragon fruit or pitahaya belongs to the Cactaceae family. This exotic fruit has become popular in Europe and the United States owing to its high nutritional value and potential health-promoting properties. The aim of this work was to study the case of a patient with anaphylaxis after the ingestion of dragon fruit.

We present the case of a 26-year-old man who experienced a systemic reaction requiring hospitalization 1 hour after ingesting a pitahaya. He was also taking nonsteroidal anti-inflammatory drugs and amoxicillin, which he has subsequently tolerated. His personal history includes allergic rhinitis to Salsola kali pollen, which was treated with immunotherapy from 2016 to 2018.

The patient was diagnosed using prick-by-prick with fruits, skin prick test (SPT) with aeroallergens and specific IgE by ImmunoCAP and ISAC. Prick-by-prick was positive to pitahaya and peach. SPT was positive to grasses, Olea europaea, Parietaria judaica, S. kali, and Platanus acerifolia and negative to LTP and profilin. ImmunoCAP was positive for peach (1.12 kU_A/L), Pru p 1 (0.38 kU_A/L), and Pru p 3 (3.56 kU_A/L). ISAC was positive for most grass allergens, Cup a 1, Ole e 1, Par j 2, Sal k 1, polcalcin, mites, and cat, with the highest values for Sal k 1 (76 ISU-E) and LTP Par j 2 (66 IUS-E).

Pitahaya pulp was used to prepare an extract. The protein concentration was determined by Bradford. Fifteen micrograms of protein were loaded into a TGX gel to study the protein profile. In the protein profile, the most intense bands were observed at 9, 26, and 56 kDa.

Protein recognition by IgE was studied by immunoblot. The patient's IgE recognized several bands ranging from 16 to >100 kDa, the most intense being those at approximately 18, 27, 37, 47, and 54 kDa.

Cross-reactivity with S. kali and peach peel extract was studied using immunoblot inhibition. The S. kali extract almost completely inhibited recognition of pitahaya, leaving only a slight recognition of the 54-kDa band. The peach peel extract completely inhibited the pitahaya extract.

In conclusion, sensitization to pitahaya was confirmed by the IgE-mediated recognition of several protein bands. This sensitization was probably due to cross-reactivity with S. kali and peach allergens, to which the patient was also sensitized. Moreover, cofactors may have contributed as aggravating elements.

This case warns of the introduction of new foods in the diet, especially in patients previously sensitized to pollen or other foods.