Heterogeneity of Pollen Food Allergy Syndrome in Seven Southern European Countries: the @IT.2020 Multicenter Study.

BACKGROUND Pollen food allergy syndrome (PFAS) is a frequently underdiagnosed disease due to diverse triggers, clinical presentations, and test results. This is especially relevant in geographic areas with a broad spectrum of pollen sensitization, such as Southern Europe. OBJECTIVES To elucidate similarities and differences ofPFAS in nine Southern European centers and identify associated characteristics and unique markers of PFAS. METHODS As part of the @IT.2020 Multicenter Study, 815 patientswith seasonal allergic rhinitis (SAR),aged 10-60 years, were recruited in seven countries. They completed questionnaires regarding SAR, comorbidities, family history, and PFAS, underwent skin prick testing (SPT) and serum IgE testing. RESULTS Of the 815 patients, 167 (20.5%) reported PFAS reactions.Most commonly, eliciting foods were kiwi (58, 34.7%), peach (43, 25.7%), and melon (26, 15.6%). Reported reactions were mostlylocal (216/319, 67.7%), occurring within five minutes of contact with elicitors (209/319, 65.5%).Associated characteristicsincluded positive IgE to at least one panallergen (profilin, PR-10, or nsLTP) (p=.007), maternal PFAS (OR:3.716, p=.026), and asthma (OR:1.752, p=.073).Between centers, heterogeneity in prevalence (Marseille: 7.5% vs. Rome: 41.4%, p<.001) and of clinical characteristics was apparent. Cypress played a limited role, with only 1/22 SPT mono-sensitized patients reporting a food-reaction (p<.073). CONCLUSIONS PFAS is a frequent comorbidity in Southern European SARpatients. Significant heterogeneity of clinical characteristics in PFAS patients amongst the centers was observed, and may be related to the different pollen sensitization patterns in each geographical area.IgE to panallergen(s), maternal PFAS, and asthma could be PFAS-associated characteristics.