Difficult management of a patient with pr10 related anaphylaxis

Proteins belonging to pathogenesis-related (PR10) ones consist in Bet v 1 homologues, proteins that have an aminoacid sequence homology with the allergen Bet v 1 from birch pollen [1].
Bet v 1 is the major allergen of birch and about 50–70% of birch pollen allergic patients, usually after respiratory sensitization, report symptoms after ingestion of fruits and vegetables, such as tree nuts, kiwi, soybean and those belonging to the Rosaceae family (apple, pear, peach, plum, apricot, almond) and Apiaceae family (celery, carrot, fennel). Other Bet v 1 homologues include Mal d 1 from apple, Pru p 1 from peach, Pru a v 1 from cherry, Pru a r 2 from apricot, Pyr c 1 from pear, Api γ 1 from celery, Dau c 1 from carrot and Cor a 1 from hazelnut [2].
Many proteins homologous to Bet v 1, in particular those present in the fruits of the Rosaceae family, are extremely labile and easily degraded by heat, oxidation, procedures of extraction, pepsin digestion and they are randomly distributed in pulp and peel [3, 4]. For this reason the skin prick tests with commercial extracts of foods are less specific than those with fresh fruits and vegetables, and remain the best method for the diagnosis of food allergy in these patients [5].
Therefore, PR10 allergic patients mostly experience local reactions in the oropharyngeal mucosa (oral allergy syndrome – OAS: oral itching, swelling of the lips, tongue and throat, hoarseness and laryngeal oedema) after eating fresh foods, while they usually tolerate heat-processed foods such as commercial fruit juices.
In the literature there are few articles about PR-10 related proteins induced anaphylaxis [6–8].
We describe the case of a 30-year-old girl with perennial rhinoconjunctivitis and asthma with an aggravation from February to June, who referred OAS after the ingestion of apricot, cherry and strawberry, and throat constriction, generalized urticaria, lip and palpebral oedema after eating apple, kiwi, peach, pear, pepper and juice with carrots, lemon and orange.
We performed an allergological evaluation including skin prick tests (SPT) to aeroallergens, latex, vegetables and panallergens (apple PR10 50 µg/ml, peach Lipid Transfer Protein 50 µg/ml and palm profiling 50 µg/ml) (Alk-Abellò, Milan, Italy) and assay of specific IgE (UniCAP, Phadia, Uppsala, Sweden) for the positive allergens. Moreover, the culprit vegetables have been investigated by the prick by prick method.
The patient had...


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