Hypersensitivity to mugwort (Artemisia vulgaris) in patients with peach allergy is due to a common lipid transfer protein allergen and is often without clinical expression.
BACKGROUND
The observation of mugwort-specific IgE antibodies in patients with peach allergy suggests that mugwort sensitization might play a role in sensitization to peach.


OBJECTIVE
We sought to study the clinical manifestations of mugwort hypersensitivity in patients with peach allergy, identify the common allergens, and evaluate their IgE crossreactivity.


METHODS
Patients with oral allergy syndrome for peach and specific IgE antibodies to mugwort were investigated for respiratory symptoms during the mugwort season. Peach and mugwort allergens were identified by means of SDS-PAGE and IgE immunoblotting. Immunoblotting inhibition experiments were done to study cross-reactivity between peach and mugwort and other pollens.


RESULTS
Seventeen patients were studied, 10 with no seasonal respiratory symptoms and 7 with clear late summer respiratory symptoms. In IgE immunoblotting the 10 asymptomatic patients reacted only to a 9-kd allergen of both mugwort and peach, whereas the 7 patients with pollinosis reacted to other allergens. Ten patients with mugwort allergy, no history of allergy to peach, and negative results for peach-specific IgE antibodies were also studied. The mugwort 9-kd protein was identified as a lipid transfer protein (LTP) homologous to peach LTP. Immunoblotting inhibition showed that IgE binding to the peach 9-kd band was totally inhibited by 4 microg of peach LTP but only by 400 microg of mugwort LTP, whereas 4 microg of both mugwort and peach LTP totally inhibited the mugwort immunoblotting. The results were similar with other pollens.


CONCLUSIONS
Patients sensitized only to the 9-kd LTP of mugwort do not present hay fever symptoms, and this sensitization is a consequence of the peach sensitization.
Pastorello
Elide A
EA
Allergy Center, 3rd Division of General Medicine, Ospedale Maggiore IRCCS, Via Francesco Sforza 35, 20122 Milan, Italy.
Pravettoni
Valerio
V
Farioli
Laura
L
Rivolta
Federica
F
Conti
Amedeo
A
Ispano
Marco
M
Fortunato
Donatella
D
Bengtsson
Anders
A
Bianchi
Matilde
M
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D019306:Artemisia / Q000009:adverse effects*; D002352:Carrier Proteins / Q000276:immunology*; D003429:Cross Reactions; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D010940:Plant Proteins; D011058:Pollen / Q000276:immunology*; D027861:Prunus / Q000009:adverse effects*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*
D000485:Allergens; D052179:Antigens, Plant; D002352:Carrier Proteins; D010940:Plant Proteins; C511920:lipid transfer proteins, plant; D007073:Immunoglobulin E