Identification of cross-reactive and genuine Parietaria judaica pollen allergens.
BACKGROUND
The weed Parietaria judaica is one of the most important pollen allergen sources in the Mediterranean area.


OBJECTIVE
We sought to identify P judaica pollen allergen, which might be used to serologically distinguish genuine Parietaria sensitization and cross-reactivity to allergens from other weed species (eg, mugwort and ragweed).


METHODS
The allergen profile of P judaica IgE-reactive sera from weed pollen-sensitized allergic individuals from the Mediterranean region (n = 36) with high Parietaria pollen exposure and from weed pollen-allergic patients with little or no Parietaria exposure (Austria, n = 42; Scandinavia, n = 8; United States, n = 19) was established by CAP FEIA measurements and by IgE immunoblot inhibition experiments with recombinant allergens.


RESULTS
The majority (83%) of the Mediterranean weed pollen-allergic patients mounted high IgE antibody levels (mean specific IgE, 20.89 kUA/L) against recombinant (r) Par j 2, whereas only 7% of the non-Mediterranean weed-allergic patients showed low IgE reactivity to rPar j 2 (mean specific IgE, 1.03 kUA/L). The cytoskeletal protein profilin and a 2-EF-hand calcium-binding allergen were identified as cross-reactive Parietaria allergens, which were recognized preferentially by Parietaria -positive, non-Mediterranean weed pollen-allergic patients.


CONCLUSIONS
rPar j 2 might be used as a diagnostic marker allergen to identify weed pollen-allergic patients who are genuinely sensitized against Parietaria pollen and thus would be particularly suited for specific immunotherapy with Parietaria pollen extract.
Department of Pathophysiology, AKH, University of Vienna, Vienna, Austria.
Sabine
S
Stumvoll
Kerstin
K
Westritschnig
Jonas
J
Lidholm
Susanne
S
Spitzauer
Paolo
P
Colombo
Giovanni
G
Duro
Dietrich
D
Kraft
Domenico
D
Geraci
Rudolf
R
Valenta
D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D003429:Cross Reactions; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007167:Immunotherapy; D032403:Parietaria / Q000276:immunology*; D010936:Plant Extracts / Q000276:immunology; D011058:Pollen / Q000276:immunology*
D000485:Allergens; D052179:Antigens, Plant; C103299:Par j 2.0101; D010936:Plant Extracts; D007073:Immunoglobulin E