The frequency of phospholipase A2 binding of basophilic granulocytes does not decrease during bee-venom-specific immunotherapy.
BACKGROUND
The major allergenic component of bee venom is phospholipase A2 (PLA2).


METHODS
In this study, PLA2 was used to analyze and enrich PLA2-binding cells from peripheral blood by high gradient magnetic cell sorting.


RESULTS
In normal donors, the frequency of allergen (PLA2)-binding cells among peripheral blood mononuclear cells (PBMC) as determined by flow cytometry is below 0.1%, whereas in bee-venom-allergic patients, PLA2-binding cells are readily detectable at frequencies of up to 2.3%. In severely bee-venom-allergic patients, many basophilic granulocytes are present, as defined by anti-CD9, CD25, and CD38 mAb, comprising up to 95% of the PLA2-binding cells. From blood of allergic and normal donors, about equal absolute numbers of allergen-binding CD19/21-positive B cells can be enriched. Severe anaphylactic reactions (Mueller grade IV) and failure of or adverse reactions during immunotherapy are associated with high numbers of circulating allergen-binding basophils. Interestingly, in the patients studied, the number of PLA2-binding basophilic granulocytes did not markedly change during rush immunotherapy and up to 6 months of maintenance immunotherapy.


CONCLUSIONS
The specific and reproducible enrichment of PLA2-binding cells provides a new tool for the analysis and monitoring of effector cells in bee-venom-allergic patients with immediate-type hypersensitivity.
Irsch
J
J
Department of Genetics, University of Cologne, Germany.
König
C
C
Löhndorf
A
A
Tesch
H
H
Krieg
T
T
Merk
H
H
Radbruch
A
A
Hunzelmann
N
N
D000293:Adolescent; D000328:Adult; D001491:Basophils / Q000166:cytology* / Q000378:metabolism*; D001514:Bee Venoms / Q000008:administration & dosage / Q000276:immunology*; D003888:Desensitization, Immunologic; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000628:therapy*; D018189:Immunomagnetic Separation; D007958:Leukocyte Count; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D012882:Skin Tests
D001514:Bee Venoms; D010741:Phospholipases A; D054467:Phospholipases A2