Recombinant allergens promote expression of CD203c on basophils in sensitized individuals.
BACKGROUND
Traditionally, the diagnosis of type I allergies is based on clinical data, skin test results, and laboratory test results with allergen extracts. During the past few years, several attempts have been made to refine diagnostic assays in clinical allergy by introducing recombinant allergens and novel markers of IgE-dependent cell activation.


OBJECTIVE
We have identified the ectoenzyme CD203c as a novel basophil antigen that is upregulated on IgE receptor cross-linkage. In this study we applied CD203c and a panel of recombinant allergens to establish a novel basophil test that allows for a reliable quantification of IgE-dependent responses at the effector cell level.


METHODS
Patients allergic to birch (Bet v 1, n = 15; Bet v 2, n = 8) and grass (Phl p 1, n = 15; Phl p 2, n = 10; Phl p 5, n = 14) pollen allergens, as well as 10 nonallergic donors, were examined. Basophils were exposed to various concentrations of recombinant allergens for 15 minutes and then examined for expression of CD203c by means of flow cytometry. CD203c upregulation was correlated with the increase in CD63.


RESULTS
Exposure to recombinant allergens resulted in a dose-dependent increase in expression of CD203c on peripheral blood basophils in sensitized individuals, whereas no increase was seen in healthy control subjects. The effects of the recombinant allergens on CD203c expression were also time dependent. There was a good correlation between allergen-induced upregulation of CD203c and upregulation of CD63 (R = 0.76).


CONCLUSIONS
Flow cytometric quantitation of CD203c on blood basophils exposed to recombinant allergens is a useful approach to determine the allergic state in sensitized individuals and represents a basis for a sensitive novel allergy test.
Department of Internal Medicine I, Division of Hematology and Hemostaseology, University of Vienna, Vienna, Austria.
Alexander W
AW
Hauswirth
Susanne
S
Natter
Minoo
M
Ghannadan
Yasamin
Y
Majlesi
Gerit-Holger
GH
Schernthaner
Wolfgang R
WR
Sperr
Hans-Jörg
HJ
Bühring
Rudolf
R
Valenta
Peter
P
Valent
D000485:Allergens / Q000008:administration & dosage / Q000276:immunology*; D015703:Antigens, CD / Q000378:metabolism; D001491:Basophils / Q000276:immunology*; D029662:Betula / Q000276:immunology; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006636:Histamine Release; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010940:Plant Proteins / Q000008:administration & dosage / Q000276:immunology*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D006109:Poaceae / Q000276:immunology; D011755:Pyrophosphatases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology*; D060149:Tetraspanin 30; D015854:Up-Regulation
D000485:Allergens; D015703:Antigens, CD; C554586:CD63 protein, human; C427944:ENPP3 protein, human; D010940:Plant Proteins; D010980:Platelet Membrane Glycoproteins; D011994:Recombinant Proteins; D060149:Tetraspanin 30; D007073:Immunoglobulin E; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases