title: Effect on cell surface markers following allergen-induced desensitization of human whole-blood basophils.
abstract: BACKGROUND
  Allergen-specific immunotherapy (SIT) leads to reduced symptoms upon allergen exposure through as yet unresolved mechanisms. Desensitization of basophils to specific allergens during the updosing phase of injection immunotherapy may contribute to the clinical effect of SIT. Here we report a protocol for efficient in vitro allergen-mediated desensitization of basophils in whole blood and the effect of desensitization on the expression of basophil activation markers (CD203c and CD63) as well as histamine release in response to allergen challenge.
  
  
  METHODS
  Whole blood from grass pollen-allergic subjects was incubated with Phleum pratense extract by stepwise increase of the allergen concentration in the culture from well below to well above the allergen threshold concentration for activation of basophils. Desensitization was determined by measuring the expression of the basophil activation markers CD63 and CD203c by FACS following challenge with high allergen concentrations.
  
  
  RESULTS
  The basophil desensitization protocol reported here affected both the expression of the cell-surface markers and the levels of histamine release. Following the stepwise desensitization procedure the whole-blood basophils were not activated when challenged with more than 10-fold increased allergen concentration.
  
  
  CONCLUSIONS
  We have established a protocol for basophil desensitization. By mimicking the updosing phase of immunotherapy we raised the allergen threshold for basophil activation and obtained efficient desensitization for all donors. We showed that conditions leading to desensitization affect histamine release and expression of different basophil markers alike.
authors.affiliation: Experimental Immunology, ALK-Abelló, Hørsholm, Denmark. gildk@alk-abello.com
authors.forename: Gitte
authors.initials: G
authors.lastname: Lund
authors.forename: Henrik
authors.initials: H
authors.lastname: Jacobi
authors.forename: Per Stahl
authors.initials: PS
authors.lastname: Skov
authors.forename: Jens
authors.initials: J
authors.lastname: Holm
authors.forename: Kaare
authors.initials: K
authors.lastname: Lund
mesh_terms: D000485:Allergens / Q000276:immunology / Q000378:metabolism; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D015549:Basophil Degranulation Test; D001491:Basophils / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D003888:Desensitization, Immunologic; D004306:Dose-Response Relationship, Immunologic; D005434:Flow Cytometry; D006632:Histamine / Q000378:metabolism; D006801:Humans; D031784:Phleum; D010727:Phosphoric Diester Hydrolases / Q000276:immunology / Q000378:metabolism*; D010940:Plant Proteins / Q000276:immunology / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism*; D011755:Pyrophosphatases / Q000276:immunology / Q000378:metabolism*; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D060149:Tetraspanin 30
chemical_list: D000485:Allergens; D015703:Antigens, CD; D015415:Biomarkers; C554586:CD63 protein, human; C427944:ENPP3 protein, human; D010940:Plant Proteins; D010980:Platelet Membrane Glycoproteins; D060149:Tetraspanin 30; C090396:PHLPI protein, Phleum pratense; D006632:Histamine; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases