Adverse reactions to nonsteroidal anti-inflammatory drugs and hypersensitivity to lipid transfer proteins

Lipid transfer proteins (LTP) constitute a family of proteins widely distributed through the plant kingdom [1]. Allergenic LTP have been identified in tree pollen and weeds, plant food allergen sources and latex. The primary sensitizer agent and the fruit mostly involved seems to be the peach [2]. Allergy to LTP has been mainly described in Italy, Spain and Greece [3] and only exceptionally in the Central and Northern Europe. The allergenic potential of LTP is influenced by their localization and stability to proteolytic and thermal dena-turation: indeed LTP are stable molecules, predominantly present in the fruit peel; it might explain why some LTP-sensitized individuals easily tolerate fruits without peel [4, 5]. Due to its heat and pepsin-resistance, LTP may determine local symptoms such as the oral allergy syndrome and systemic symptoms up to anaphylaxis after the in-gestion of fruits and vegetables [6]. Previous studies documented the connection among hypersensitivity to LTP and reactions to nonsteroidal anti-inflammatory drugs (NSAIDS) [7]. We describe the case of a patient, a 33-year-old woman with generalized urticaria and angioedema thirty minutes after eating a veal steak and lettuce; after lunch she also took an oral film of ketoprofen for headache. Skin prick tests (SPT) with commercial extracts of many plant foods The patient had positive SPT to apple, hazelnut, peach, soy and celery and specific IgE positive (> 0.35 U/ ml) only to apple (0.83 U/ml), peach (1.70 U/ml) and hazelnut (3.73 U/ml). The patient told us she did not eat currently these foods because previously she presented oral allergy syndrome (which includes itching and swelling of the lips, palate and tongue) after their ingestion. SPT (Alk-Abello, Milan, Italy) with the commercial extracts of LTP and profilin were performed: only LTP was positive; we also detected specific IgE (UniCAP, Phadia, Uppsala, Sweden) for the recombinant allergen Pru p 3 whose value was 0.44 U/ml. Moreover SPT and patch test with ketoprofen were negative. Before the reaction she had already taken ketoprofen without symptoms but she had never associated the intake of this drug with the ingestion of lettuce (which is one of the plant foods-containing LTP). When she came to our attention she had already reintroduced veal steak in her diet without presenting reactions. On the basis of these results we decided to perform an oral test with ketoprofen oral film 80 mg: we diluted the drug in 10 ml of water and we administered …