Pru p 7 and other gibberellin-regulated proteins: sweet fruit for the allergists
Résumé
Background: The gibberellin-regulated protein (GRP) family, unknown as allergens until 2013, has become the latest addition to allergens involved in pollen-food allergy syndromes, expanding that group to almost ten members characterized until 2020. While peach, Japanese apricot and orange are confirmed GRP sources, patients’ history suggests that GRP sensitization might be associated with clinical reactions to a wide array of other fruits. In this study, we sought to identify such fruits, other than peach, which may be involved in GRP-related food allergy in Southern France.
Method: The study included 386 patients (median age 19, range 1-74; sex ratio 0.9) attending one of the participating allergy practices for suspected fruit allergy. Diagnosis of fruit allergy was based on a detailed anamnesis and sensitization to the culprit fruit. Skin prick tests were performed with commercial extracts and native fruit. Oral food challenges were performed in a minority of cases. IgE to Pru p 1, Prup 3, Pru p 4, and Pru p 7 served as markers of PR-10, LTP, profilin, and GRP sensitization, and Cup a 1 as a marker of Cupressaceae sensitization.
Results: Allergy to fruits other than peach was demonstrated in 204 (53%) patients of whom 116 (63%) were sensitized to Pru p 7. Allergy to Rosaceae fruits, kiwifruit, citrus fruits, tomato, and fig was present in 91 (24%), 46 (12%), 34 (9%), 19 (5%), and 7 (2%) patients, respectively. The prevalence of Pru p 7 sensitization ranged from 86% (fig) to 42% (tomato). Among Pru p 7-sensitized fruit allergic patients, apparent monosensitization to Pru p 7 was highest in citrus and fig allergy (85 and 83%) and lowest in kiwifruit allergy (27%). Allergy to pomegranate, suspected in 4 patients, could not be confirmed. All severity grades were represented. Cofactor involvement, usually exercise, was reported for 14% Pru p 7-sensitized patients. A “multifruit syndrome”, defined as confirmed reactions to more than 3 fruit families, was present in 92 patients (24%) of whom 52 (57%) were sensitized to Pru p 7 (28 with apparent monosensitization, or 54%). Primary sensitization to Cupressaceae was present in all Pru p 7-sensitized patients.
Conclusion: GRP sensitization is frequent in fruit allergic Mediterranean patients with Cupressaceae pollinosis. Allergists receiving patients with a current or past history of living in a Cupressaceae pollination area should be aware of GRP-related fruit allergy and its hallmark sensitization to Pru p 7.