Basophil CD203c levels are increased at baseline and can be used to monitor omalizumab treatment in subjects with nut allergy.
BACKGROUND
Basophils contribute to anaphylaxis and allergies. We examined the utility of assessing basophil-associated surface antigens (CD11b/CD63/CD123/CD203c/CD294) in characterizing and monitoring subjects with nut allergy.


METHODS
We used flow cytometry to analyze basophils at baseline (without any activation) and after ex vivo stimulation of whole blood by addition of nut or other allergens for 2, 10, and 30 min. We also evaluated whether basophil expression of CD11b/CD63/CD123/CD203c/CD294 was altered in subjects treated with anti-IgE monoclonal antibody (omalizumab) to reduce plasma levels of IgE.


RESULTS
We demonstrate that basophil CD203c levels are increased at baseline in subjects with nut allergy compared to healthy controls (13 subjects in each group, p < 0.0001). Furthermore, we confirm that significantly increased expression of CD203c occurs on subject basophils when stimulated with the allergen to which the subject is sensitive and can be detected rapidly (10 min of stimulation, n = 11, p < 0.0008). In 5 subjects with severe peanut allergy, basophil CD203c expression following stimulation with peanut allergen was significantly decreased (p < 0.05) after 4 and 8 weeks of omalizumab treatment but returned toward pretreatment levels after treatment cessation.


CONCLUSIONS
Subjects with nut allergy show an increase of basophil CD203c levels at baseline and following rapid ex vivo stimulation with nut allergen. Both can be reduced by omalizumab therapy. These results highlight the potential of using basophil CD203c levels for baseline diagnosis and therapeutic monitoring in subjects with nut allergy.
Gernez
Yael
Y
Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA.
Tirouvanziam
Rabindra
R
Yu
Grace
G
Ghosn
Eliver E B
EE
Reshamwala
Neha
N
Nguyen
Tammie
T
Tsai
Mindy
M
Galli
Stephen J
SJ
Herzenberg
Leonard A
LA
Herzenberg
Leonore A
LA
Nadeau
Kari C
KC
D000293:Adolescent; D000328:Adult; D018926:Anti-Allergic Agents / Q000627:therapeutic use*; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D001491:Basophils / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002469:Cell Separation; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D008297:Male; D021184:Nut Hypersensitivity / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D000069444:Omalizumab; D010727:Phosphoric Diester Hydrolases / Q000096:biosynthesis* / Q000187:drug effects; D011755:Pyrophosphatases / Q000096:biosynthesis* / Q000187:drug effects; D012680:Sensitivity and Specificity; D055815:Young Adult
D018926:Anti-Allergic Agents; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D015415:Biomarkers; C427944:ENPP3 protein, human; D000069444:Omalizumab; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases