Involvement of lipid transfer proteins in saffron hypersensitivity: molecular cloning of the potential allergens.

BACKGROUND Lipid transfer proteins (LTPs) are relevant allergens, and have recently been proposed as model plant allergens from fruit, vegetables, seeds, and pollens. However, no LTP spice allergen has been characterized to date. OBJECTIVES To identify and isolate saffron LTPs and to explore their relevance in saffron allergy. METHODS Six patients with rhinitis and positive skin prick test (SPT) results to saffron extract were selected. Two recombinant LTPs from saffron were isolated, cloned into pPIC9 plasmid, and produced in Pichia pastoris. Immunoglobulin (Ig) E immunodetection and enzyme-linked immunosorbent assays were performed with the 2 purified allergens and with the major peach allergen Pru p 3. RESULTS Full cDNA corresponding to 2 saffron LTP variants was isolated and expressed in P pastoris. The molecular weight of rCro s 3.01 and rCro s 3.02 was 9.15 kDa and 9.55 kDa, respectively. The sequences obtained had a 47% identity with each other and 51% and 43% with Pru p 3. Both proteins were recognized by anti-Pru p 3 antibodies. Specific IgE to the purified allergens was found in 50% of patients for rCro s 3.01 and 33% for rCro s 3.02 and Pru p 3 in the saffron-allergic patients. CONCLUSIONS Our results indicated that rCro s 3.01 and rCro s 3.02 are minor allergens of saffron, at least in the study patients. To our knowledge, this is the first report on the implication of LTPs in spice allergy.