000336 - Cutaneous Reaction After Persimmon Ingestion: Implication of a PR-10 Protein as a Possible Allergen in Diospyros kaki

Persimmon (Diospyros kaki), marketed as "persimon" at its early-ripening stage, is a widely consumed fruit in Mediterranean countries. Despite its popularity, the allergenic profile of this fruit remains poorly characterized, with only isolated reports suggesting potential IgE-mediated reactions.

A 24-year-old man with intermittent allergic rhinitis to olive pollen developed facial and upper-thoracic erythema two hours after consuming persimmon. Symptoms resolved with corticosteroids and antihistamines, without respiratory or gastrointestinal involvement. Prick-by-prick testing with fresh persimmon yielded a strong positive reaction (12 mm), whereas skin tests for profilin, LTP, and common cross-reactive fruits were negative.

Protein extracts from persimmon and ripened kaki were prepared. SDS-PAGE under reducing and non-reducing conditions and IgE Western blot using the patient’s serum were performed to characterize IgE-binding components.

Both persimmon and kaki extracts showed comparable protein profiles regardless of redox conditions. IgE Western blot revealed a prominent 18–19 kDa band recognized by the patient’s IgE in all extracts except persimmon under reducing conditions, suggesting that epitope recognition depends on the protein’s native conformation.Although no allergens from Diospyros kaki are listed in the WHO/IUIS database, Allergome includes Dio k 1 (PR-10), Dio k 2 (profilin), and Dio k IFR. Considering the band size (18–19 kDa), the negative profilin testing, and the exclusion of isoflavone reductase based on molecular weight, a PR-10 protein is the most plausible candidate.

This case indicates that persimmon can elicit IgE-mediated allergic reactions, with a PR-10-like protein as the potential culprit. The similar allergenic profiles observed between persimmon and fully ripened kaki suggest that the maturation stage does not substantially modify PR-10 expression in this patient’s case. Preliminary molecular characterization highlights the need for further systematic investigation of this emerging food allergen source.