Lipid-transfer proteins (LTPs) exist in all branches of the plant kingdom (panallergens) and are able to induce both IgE sensitization and allergic reactions of different severities, including anaphylaxis. The allergens have a molecular weight of 6–10 kDa and show both high thermal and proteolytic stability. In addition to foods (fruits and vegetables), LTPs can also be found in pollen. Sensitization toward LTPs seems to occur via food intake; the clinical relevance of cross-reactivities to pollen-derived LTPs is still unclear. Allergic reactions to LTPs occur predominantly in the Mediterranean areas and are rare in Northern and Central Europe. In Southern Europe IgE reactivity to peach LTP (Pru p 3) is frequently diagnosed. For this reason Pru p 3 is used as a marker allergen. For practical clinical issues, the improvement of allergy diagnosis (by component-resolved methods) has priority over the avoidance of LTPs in allergy-causing foods from the diet. At present, allergen-specific immunotherapy is not available.
