Measurement of IgE antibodies to shrimp tropomyosin is superior to skin prick testing with commercial extract and measurement of IgE to shrimp for predicting clinically relevant allergic reactions after shrimp ingestion.
BACKGROUND
Shrimp is a frequent cause of food allergy. Tropomyosin is the major allergen in shrimp, and it shares homology to tropomyosins from other crustaceans, dust mites, cockroach, and parasites.


OBJECTIVE
The aim of this study was to determine the value of detection of IgE to shrimp tropomyosin in the diagnosis of shrimp allergy.


METHODS
We have studied 35 patients with asthma, rhinitis, or both who were sensitized to Dermatophagoides pteronyssinus. All subjects underwent skin prick testing in addition to double-blind, placebo-controlled food challenges (DBPCFC); oral open challenges; or both with shrimp. Measurements of IgE to shrimp and shrimp tropomyosin were carried out by means of CAP and chimeric ELISA, respectively.


RESULTS
Oral challenges confirmed the diagnosis of shrimp allergy in 7 patients. IgE measurement to shrimp tropomyosin was positive in 71.4% of the patients with shrimp allergy. Of the 28 patients without shrimp allergy, only 7.1% (2/28) had IgE to shrimp tropomyosin compared with 25% (7/28) who had IgE to shrimp and 35.7% (10/28) who had positive skin prick test responses to shrimp. Sensitivity was similar for all 3 methods (71.4%); in contrast, specificity of IgE to shrimp tropomyosin (92.8%) was greater than that of IgE to shrimp (75%) and skin prick testing (64.2%). With regard to diagnostic efficiency, measurement of IgE to shrimp tropomyosin was superior to measurement of IgE to shrimp and skin prick testing (88.5%, 74.2%, and 65.7%, respectively).


CONCLUSIONS
Use of measurements of IgE to shrimp tropomyosin provided added value to the diagnosis of shrimp allergy.
Division of Clinical Immunology and Allergy, University of São Paulo School of Medicine, São Paulo, Brazil.
Ariana C
AC
Yang
L Karla
LK
Arruda
Ana Beatriz R
AB
Santos
Michelle C R
MC
Barbosa
Martin D
MD
Chapman
Clóvis E S
CE
Galvão
Jorge
J
Kalil
Fábio F
FF
Morato-Castro
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D000918:Antibody Specificity; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis*; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D008875:Middle Aged; D033561:Penaeidae / Q000145:classification / Q000276:immunology*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012882:Skin Tests; D014335:Tropomyosin / Q000276:immunology*; D055815:Young Adult
D000485:Allergens; D014335:Tropomyosin; D007073:Immunoglobulin E