Clinical Relevance

Anecdotal evidence suggests that Jack fruit can occasionally induce symptoms of food allergy in sensitized individuals; however, few studies have been reported to date. Increased consumption of this fruit will result in a rise in allergic reactions. Ingestion of jackfruit resulting in anaphylaxis has been reported in 3 individuals.

A 30-year-old Filipino man with pollen allergy developed symptoms of oral allergy syndrome (OAS) after eating raw apple, raw peach, raw celery, and Jack fruit. Despite evidence of multiple sensitization in skin-prick tests and serum IgE tests for birch, grass and mugwort pollen, related fruits and vegetables, and Jack fruit, in RAST inhibition studies neither rBet v 1 nor rBet v 2 (profilin) – the well-known cross-reacting allergenic components in OAS – could inhibit the specific IgE response to Jack fruit. Whether the reaction to Jack fruit is specific or whether other pollen-related cross-reacting allergenic components exist could not be elucidated, and the authors suggested that this should be further investigated.

Two Jack fruit-allergic patients are described. Both patients claimed they had never eaten Jack fruit before. A 31-year-old man with a history of hay fever in the birch pollen season increasingly reported episodes of OA symptoms after eating apple, hazelnut or peanut. He developed oral allergy symptoms within 5 minutes of eating a very small piece of fresh Jack fruit. Within 10 minutes, that had progressed to hoarseness, swelling of the throat and dyspnoea. A 27-year-old female with hay fever in the birch and grass pollen season reported increased oral allergy-like symptoms after eating apple, hazelnut and peanut. She experienced oral allergy symptoms and abdominal cramps within 5 minutes of eating a small piece of fresh Jack fruit. Double-blind placebo-controlled challenges confirmed the diagnosis in both patients. Skin-prick tests were positive, and serum-specific IgE to Jack fruit was 5.9 and 0.8 IU/ml for the 2 patients. Sensitization was demonstrated to a Bet v 1-related allergen. Five patients with concomitant birch pollen and fruit allergy who underwent an oral challenge with Jack fruit developed oral allergy, confirming the presence of a panallergen and suggesting that individuals with both birch pollen and fruit allergy should avoid this fruit.

Adverse reactions to lectins present in the fruit are possible, including the agglutination of red blood cells in humans and animals.

Cross-Reactivity

Cross-reactivity among the different individual species of the genus could be expected.

To assess whether Jack fruit allergy might be common in patients with birch pollen and fruit allergy, 5 birch-pollen and concomitant fruit-allergy patients were orally challenged with Jack fruit. All 5 developed symptoms of oral allergy. The study concludes that Jack fruit contains at least 1 panallergen, which may result in birch pollen-related food allergy.