Parietaria judaica pollen allergen (Par j)

Parietaria pollen allergens, primarily the major components Par j 1 and Par j 2 from the weed Parietaria judaica (Pellitory-of-the-wall), are potent triggers of respiratory allergic diseases, especially in Mediterranean regions. These proteins belong to the non-specific lipid transfer protein (nsLTP) family and are characterized by their small size, high thermal stability, and resistance to proteolytic digestion, which contributes to their high allergenicity [1, 2, 4]. In the plant, they function as lipid transporters and pathogenesis-related proteins involved in defense against microbial infections [3, 12]. In humans, inhalation of these pollen grains induces a Type I hypersensitivity response characterized by the production of allergen-specific IgE and subsequent mast cell degranulation [5, 6]. Clinically, these allergens are responsible for severe allergic rhinitis, conjunctivitis, and bronchial asthma, often exacerbated by the long pollination season of the Parietaria genus [5, 17]. These molecules are the primary targets for allergen-specific immunotherapy (AIT), which uses standardized extracts or allergoids to induce immune tolerance and provide long-term symptom relief [7, 11, 16].

Other names

Pellitory-of-the-wall allergenParietaria officinalis allergenNon-specific lipid transfer proteinnsLTPPar j 1Par j 2Par o 1

Allergen-specific immunotherapy (AIT) modifies the disease course by shifting the immune response from a Th2-dominated (IgE) profile to a Th1/Treg-dominated profile, inducing the production of regulatory cytokines such as IL-10 and TGF-beta, and promoting the synthesis of allergen-specific IgG4 blocking antibodies that prevent IgE-mediated mast cell activation [9, 14, 16].