title: The frequency of phospholipase A2 binding of basophilic granulocytes does not decrease during bee-venom-specific immunotherapy.
abstract: 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.
authors.affiliation: Department of Genetics, University of Cologne, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Irsch
authors.forename: C
authors.initials: C
authors.lastname: König
authors.forename: A
authors.initials: A
authors.lastname: Löhndorf
authors.forename: H
authors.initials: H
authors.lastname: Tesch
authors.forename: T
authors.initials: T
authors.lastname: Krieg
authors.forename: H
authors.initials: H
authors.lastname: Merk
authors.forename: A
authors.initials: A
authors.lastname: Radbruch
authors.forename: N
authors.initials: N
authors.lastname: Hunzelmann
mesh_terms: 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
chemical_list: D001514:Bee Venoms; D010741:Phospholipases A; D054467:Phospholipases A2