Plant lipid transfer protein allergens: no cross-reactivity between those from foods and olive and Parietaria pollen.

BACKGROUND: Cross-reactivity among plant food allergens belonging to the nonspecific lipid transfer protein (LTP) family is well known. In contrast, the relationship among these allergens and their putative homologs from olive (Ole e 7) and Parietaria (Par j 1) pollen has not been clarified.
METHODS: Sera with specific IgE to LTP allergens were obtained from peach-, mustard- and olive pollen-allergic patients. Purified LTP allergens from foods (peach, apple, mustard and wheat) and pollens (olive, mugwort and Parietaria) were tested by ELISA and ELISA-inhibition assays.
RESULTS: Plant food LTP-allergic patients showed a significantly higher number of sera (89-100 vs. 33-64%) with specific IgE and mean specific IgE levels (0.30-1.56 vs. 0.21-0.34 OD units) to the 4 food LTP allergens tested than to olive Ole e 7 and Parietaria Par j 1 pollen. ELISA-inhibition assays indicated cross-inhibition between food LTP allergens but no cross-reactivity between these allergens and Ole e 7 and Par j 1, or, even more, between the LTP allergens from olive and Parietaria pollen.
CONCLUSIONS: LTP allergens from olive and Parietaria pollen cross-react neither with allergenic LTPs from plant foods nor between themselves. Therefore, both pollens do not seem to be related with the LTP syndrome.