The present invention relates to fusion proteins comprising differentallergens of the ns-LTPs family, and their use in the prevention and thetreatment of allergic symptoms associated to said allergens. In particular,fusion proteins in the form of heterodimers comprising the major allergens ofParietaria judaica, Par 1 and Parj 2, are described. Methods of preparation ofthe fusion proteins by expression in genetically modified host cells andpharmaceutical compositions comprising said fusion proteins are described aswell.