Use of both CD63 up regulation and IgE down regulation for the flow cytometric analysis of allergen induced basophil activation. Definition of an activation index.
OBJECTIVE
The aim of this study was to compare the use of a late (CD63) and an early (IgE) marker of basophil activation in the flow cytometric diagnosis of beta-lactam induced allergic hypersensitivity reactions.


METHODS
Twelve patients who had had a clear cut betalactam induced immediate reaction and 16 controls were selected, as well as 11 patients who had had an immediate reaction to bee or wasp stings.


METHODS
Leukocyte suspensions were incubated with allergen dilutions as well as 2 positive controls (anti-IgE and NFormyl- Methionyl-Leucyl-Phenylalanine (fMLP)). Basophils were labelled with an anti-IgE FITC (fluorescein isothiocyanate) and an anti-CD63 PE (phycoerythrin). Results were expressed as percentage CD63 expression and index calculated according to a specific algorithm including the two activation markers.


RESULTS
Significant CD63 expression (>5 %) was observed in 3/12 cases for the beta-lactam sensitized population, in 0/16 cases for the controls and in 11/11 cases for the venom sensitized population. A significant index (determined by a ROC analysis) was observed in 11/12 beta-lactam sensitized patients and in 0/16 controls.


CONCLUSIONS
These results show that IgE (an early activation marker) is more sensitive than CD63 (a later activation marker) in the diagnosis of beta-lactam allergy.
Laboratoire d'Immunologie, Hôpital universitaire Dupuytren, 2, avenue Martin-Luther-King, 87042 Limoges Cedex, France. jean.sainte-laudy@chu-limoges.fr
J
J
Sainte-Laudy
A
A
Boumediene
F
F
Touraine
I
I
Orsel
C
C
Brianchon
F
F
Bonnaud
M
M
Cogné
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000276:immunology*; D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D001491:Basophils / Q000166:cytology / Q000276:immunology*; D015536:Down-Regulation; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D007299:Insect Bites and Stings / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010980:Platelet Membrane Glycoproteins / Q000276:immunology*; D012372:ROC Curve; D060149:Tetraspanin 30; D015854:Up-Regulation; D047090:beta-Lactams / Q000276:immunology
D000485:Allergens; D015703:Antigens, CD; C554586:CD63 protein, human; D010980:Platelet Membrane Glycoproteins; D060149:Tetraspanin 30; D047090:beta-Lactams; D007073:Immunoglobulin E