Basophil activation tests for the diagnosis of food allergy in children.
BACKGROUND
Positive skin prick tests (SPT) for food allergens and specific IgE (sIgE) in serum indicate sensitization but do not enable distinction between sensitized but tolerant and clinically allergic patients.


OBJECTIVE
Herein, we evaluate the clinical relevance of basophil activation tests (BATs) for peanut or egg allergy diagnosis.


METHODS
Thirty-two peanut-allergic, 14 peanut-sensitized (sIgE(+) and/or SPT(+) to peanuts) but tolerant children and 29 controls with no history of an adverse reaction to peanuts were included. Similarly, 31 egg-allergic, 14 egg-sensitized children (sIgE(+) and/or SPT(+) to egg white) and 22 controls were studied. Flow cytometric analysis of CD63 expression or CD203c upregulation on basophils and the production of leukotrienes (LT) were performed in response to an in vitro crude peanut extract or ovalbumin (OVA) challenge.


RESULTS
After in vitro peanut challenge, the basophils from peanut-allergic children showed significantly higher levels of activation than those from controls (P<0.001). After OVA challenge, a similar distinction (P<0.001) was observed between egg-allergics and controls. Interestingly, the majority of egg- or peanut-sensitized children failed to activate basophils, respectively, in response to OVA and peanut challenge. The sensitivity of the CD63, CD203c and LT assay was 86.7%, 89.5% and 76.0% with a specificity of 94.1%, 97.1% and 94.6% for peanut allergy diagnosis. The corresponding performances of BATs applied to egg allergy diagnosis were 88.9%, 62.5% and 77.8% for the sensitivity and 100%, 96.4% and 96.4% for the specificity.


CONCLUSIONS
Neither conventional tests nor BATs are sensitive and specific enough to predict food allergy accurately. However, BATs may helpfully complete conventional tests, especially SPT, allowing improved discrimination between allergic and non-allergic individuals.
Ocmant
A
A
Clinique d'Immunobiologie, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium. aocmant@ulb.ac.be
Mulier
S
S
Hanssens
L
L
Goldman
M
M
Casimir
G
G
Mascart
F
F
Schandené
L
L
D000293:Adolescent; D015703:Antigens, CD / Q000097:blood; D015549:Basophil Degranulation Test / Q000379:methods*; D001491:Basophils / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004306:Dose-Response Relationship, Immunologic; D021181:Egg Hypersensitivity / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D004531:Eggs / Q000009:adverse effects*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D015289:Leukotrienes / Q000276:immunology; D008297:Male; D021183:Peanut Hypersensitivity / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D010727:Phosphoric Diester Hydrolases / Q000097:blood; D010980:Platelet Membrane Glycoproteins; D011755:Pyrophosphatases / Q000097:blood; D012680:Sensitivity and Specificity; D012882:Skin Tests; D060149:Tetraspanin 30
D015703:Antigens, CD; C554586:CD63 protein, human; C427944:ENPP3 protein, human; D015289:Leukotrienes; D010980:Platelet Membrane Glycoproteins; D060149:Tetraspanin 30; D007073:Immunoglobulin E; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases