Lack of neo-sensitization to Pen a 1 in patients treated with mite sublingual immunotherapy

BACKGROUND: Some studies reported the possible induction of food allergy, caused by neo-sensitization to cross-reacting allergens, during immunotherapy with aeroallergens, while other studies ruled out such possibility. OBJECTIVES: The aim of this study was to evaluate the development of neo-sensitization to Pen a 1 (tropomyosin) as well as the appearance of reactions after ingestion of foods containing tropomyosin as a consequence of sublingual mite immunization. MATERIALS AND METHODS: Specific IgE to Tropomyosin (rPen a 1) before and after mite sublingual immunotherapy in 134 subjects were measured. IgE-specific antibodies for mite extract and recombinant allergen Pen a 1 were evaluated using the immunoenzymatic CAP system (Phadia Diagnostics, Milan, Italy). RESULTS: All patients had rPen a 1 IgE negative results before and after mite SLIT and did not show positive shrimp extract skin reactivity and serological rPen a 1 IgE conversion after treatment. More important, no patient showed systemic reactions to crustacean ingestion. CONCLUSIONS: Patients did not show neo-sensitization to tropomyosin, a component of the extract (namely mite group 10) administered. An assessment of a patient's possible pre-existing sensitisation to tropomyosin by skin test and/or specific IgE prior to start mite extract immunotherapy is recommended. TRIAL REGISTRATION: This trial is registered in EudraCT, with the ID number of 2010-02035531.