An allergen from Olea europaea pollen (Ole e 7) is associated with plant-derived food anaphylaxis

Several cross-reacting proteins have been identified as responsible of the co-occurrence of pollinosis and plant-derived food allergy. This association has been mainly described in the birch-apple syndrome but other pollens such as Olea europaea and other fruits may also contain homologous proteins.

To evaluate the associations between sensitization to allergens of Olea europaea pollen and confirmed plant-derived food allergy, in addition to investigate if any pattern of clinical hypersensitivity of food allergy reaction (oral allergy syndrome (OAS) or anaphylaxis) and/or any fresh fruit or nut allergy, are associated to one or several Olea pollen allergen(s).

One-hundred and thirty-four consecutive patients diagnosed with pollinosis by Olea were studied. Of these patients only 40, reported adverse reaction to plant-derived food. Twenty-one (group A) were classified as OAS and 19 (group B) as anaphylaxis. Skin-tests with six Olea pollen allergens and several groups of fruits, were performed. Double-blind placebo-controlled food challenge (DBPCFC), confirmed the diagnostics of food allergy with the exception of patients who suffered previous anaphylactic reaction.

All patients, showed a positive skin prick test (SPT), against one or more of Olea europaea allergens. Sensitization to Ole e 7, was more frequent (P = 0.02) in patients from group B. A total of 84 DBPCFC were performed with 44% positive results. Challenge confirmed at least the 50% of positive SPT in any case (peach: 68.42%; pear: 50%; melon: 71.42% and kiwi: 53.84%). In patients from group B, significant association with O. europaea pollen allergens were found between positive SPT to Rosaceae fruits and Ole e 3 (P = 0.045) and Ole e 7 (P = 0.03); Cucurbitaceae and Ole e 7 (P = 0.03) and Actinidiaceae with Ole e 3 (P = 0.04).

The results of this study, establish a new spectrum of associations between pollens and plant-derived foods: sensitization to olive profilin (Ole e 2) is not more frequent in OAS patients. Patients with anaphylactic reaction after eating fruit are also sensitized to Ole e 7, a LTP present in Olea pollen, and suffer pollinic symptoms. Finally a polcalcin (Ole e 3) could be also associated to Olea pollen respiratory and food allergy.