Component-resolved diagnosis with recombinant allergens in patients with cherry allergy.
BACKGROUND
In pollen-related food allergy, extracts for skin prick tests (SPTs) are often not standardized, and the test reliability is affected by false-negative reactions.


OBJECTIVE
We sought to evaluate a panel of recombinant allergens (RAs) derived from one allergenic food for use in component-resolved in vivo diagnosis, taking cherry as a model food.


METHODS
Seventy-nine subjects were included in the study: 24 Swiss patients (group 1) with a positive double-blind placebo-controlled food challenge result to cherries, 23 patients with birch pollen allergy but without cherry allergy (group 2), 23 nonatopic subjects (group 3), and 9 Spanish patients with a history of a cherry allergy (group 4). SPTs were performed in duplicate by using recombinant cherry allergens (Bet v 1-related allergen: recombinant (r) Pru av 1; profilin: rPru av 4; and lipid transfer protein: rPru av 3) in concentrations of 10, 50, and 100 microg/mL. Furthermore, IgE reactivity to rPru av 1, rPru av 4, and rPru av 3 was assessed by means of immunoblot analysis.


RESULTS
SPT responses with rPru av 1, rPru av 4, and rPru av 3 were positive in 92%, 17%, and 4% of the patients in group 1; in 74%, 30%, and 0% of the patients in group 2; in 0%, 22%, and 89% of the patients in group 4; and negative for all nonatopic subjects (group 3). Thus the sensitivity of a positive SPT response to at least one of the 3 RAs was 96%. The specificities, negative predictive values, and positive predictive values with the 3 RAs were 100%, 96%, and 100% if calculated in relation to the nonatopic control group but 17%, 79%, and 60% when calculated in relation to the control group with birch pollen allergy. The correlation between SPT and immunoblotting results was excellent. Sensitization to rPru av 3 was associated with more severe symptoms than sensitization to rPru av 1.


CONCLUSIONS
SPTs with RAs proved to be highly sensitive for diagnosis of cherry allergy. Component-resolved in vivo diagnosis with standardized amounts of stable RAs allows us to determine sensitization patterns directly, to correlate them with severity of clinical symptoms, and to analyze geographic differences.
Allergy Unit, Department of Dermatology, University Hospital, Zurich, Switzerland.
Barbara K
BK
Ballmer-Weber
Stephan
S
Scheurer
Philipp
P
Fritsche
Ernesto
E
Enrique
Anna
A
Cistero-Bahima
Tanja
T
Haase
Brunello
B
Wüthrich
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000235:genetics / Q000276:immunology; D052179:Antigens, Plant; D029662:Betula / Q000276:immunology; D002648:Child; D003429:Cross Reactions; D004311:Double-Blind Method; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis*; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology; D011058:Pollen / Q000276:immunology; D027861:Prunus / Q000009:adverse effects / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D012680:Sensitivity and Specificity; D012882:Skin Tests
D000485:Allergens; D052179:Antigens, Plant; C109472:PRUA1 protein, Prunus avium; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E