Sensitization to Gibberellin-regulated protein (Peamaclein) among Italian cypress pollen-sensitized patients

Background and objective: Peach gibberellin-regulated protein (peamaclein) has recently emerged as a relevant food allergen in cypress pollen-hypersensitive patients. Objective: We looked for mono-sensitization to peamaclein among Italian cypress-pollen allergic patients. Material and methods: 835 cypress pollen hypersensitive patients from 28 Italian allergy centers under went thorough interview for food-allergic reactions, and SPT with a commercial peach extracts containing peamaclein. In peach reactors, IgE to rPru p 3 was measured, and those scoring negative were enrolled as potentially mono-sensitized to peamaclein. IgE reactivity to rPru p 7 was evaluated by immunoblot and by an experimental ImmunoCAP with rPru p 7. Results: Peach SPT scored positive in 163 (19.5%) patients but 127 (77,9%) were excluded because Pru p 3 reactors. Twenty-four (14,7%, corresponding to 2.8% of the entire study population) were considered as potentially mono-sensitized to peamaclein. Their distribution did not show any geographic preference. Seventeen/24 (70,8%) had a history of food allergy, in most cases (n=15) to peach. Other offending foods included other Rosaceae, citrus fruits, fig, melon, tree nuts, and kiwi. On peach immunoblot, only 3/18 putative peamaclein allergic subjects reacted to a band at about 7kDa; 4 other patients reacted at about 50-60 kDa. Ten/18 (56%) scored positive for Pru p 7 on ImmunoCAP. Conclusion: Peamaclein allergy and sensitization prevalence seem rare in Italy. Most patients react to peach, albeit other Rosaceae fruits and several citrus fruits may also act as offending foods. Peach and cypress pollen probably share also cross-reacting allergens other than peamaclein.