Allergic reactions to jackfruit in birch pollen allergic patients

Abstract

Rationale Confirm allergy to jackfruit in 2 patients with an according personal history and characterize allergens and cross-reactivity of specific IgE antibodies to (birch) pollen and food allergens. In addition, determine the prevalence of jackfruit allergy in a group (n=5) of birch pollen (BP) and food allergic patients. Methods All patients underwent skin prick testing (SPT). Two patients were tested in a double-blind placebo-controlled food challenge (DBPCFC) and the additional 5 underwent an open challenge (OC) with jackfruit. Specific IgE was measured with the radio-allergosorbent test (RAST). RAST and immunoblot (inhibitions) were carried out. In the 2 jackfruit allergic patients, basophil histamine release was measured with several allergens. Results Both patients had positive SPT responses to jackfruit and BP and reacted with oral allergy symptoms (OAS) in the DBPCFC. The 5 selected patients reacted with OAS in the OC. Specific IgE of patient 1 to jackfruit was completely inhibited by BP extract and natural (n)Bet v 1 in RAST and immunoblot inhibition. In addition, this patient showed histamine release upon stimulation with jackfruit, apple or BP extracts and nBet v 1. Conclusions Sensitization to jackfruit allergy is due to the cross-reactive BP allergen Bet v 1. The prevalence of jackfruit allergy in the selected group of 5 patients was 100%, but jackfruit is not regularly consumed in Northern Europe, explaining why jackfruit allergy is not common.