title: Basophilic histamine content and release during venom immunotherapy: insights by flow cytometry.
abstract: BACKGROUND
  Despite the efficiency of venom immunotherapy, the effects on basophils and mast cells remain incompletely understood and probably vary according to the treatment phase.
  
  
  OBJECTIVE
  To study the effect of build-up and maintenance venom immunotherapy on individual basophils.
  
  
  METHODS
  Intracellular histamine and its release was analyzed flow cytometrically by a new enzyme-affinity method using diamine oxidase conjugated to laser-excitable fluorochromes. Phenotyping of cells included flow cytometric quantification of CD63 and CD203c. Analyses of basophil activation experiments were performed before the start of treatment, after build-up therapy and during maintenance therapy.
  
  
  RESULTS
  Before the start of therapy, patients demonstrated significantly higher numbers of basophils when compared with stung control individuals. At the end of build-up therapy a decrease of basophil numbers was observed, whereas during maintenance therapy basophil counts returned to pretreatment values. Before the start of therapy, the intracellular histamine content per cell in patients was significantly higher when compared with stung control individuals. During maintenance therapy intracellular histamine content decreased to values observed in stung control individuals. In addition, maintenance therapy lowered the net release of histamine per cell in response to optimal stimulation with wasp venom.
  
  
  CONCLUSIONS
  We introduce a novel technique that enables to assess the effects of venom immunotherapy on basophils. This new technique may help to monitor treatment effects in individual patients and could aid in the development of more efficient and better tolerated immunotherapy protocols.
authors: Faculty of Medicine and Health Science, Department of Immunology, Allergology, Rheumatology, University of Antwerp, Antwerp University Hospital, 2610 Antwerpen, Belgium.
authors: S
authors: S
authors: Nullens
authors: V
authors: V
authors: Sabato
authors: M
authors: M
authors: Faber
authors: J
authors: J
authors: Leysen
authors: C H
authors: CH
authors: Bridts
authors: L S
authors: LS
authors: De Clerck
authors: F H
authors: FH
authors: Falcone
authors: M
authors: M
authors: Maurer
authors: D G
authors: DG
authors: Ebo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001491:Basophils / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D002648:Child; D003888:Desensitization, Immunologic / Q000379:methods; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D015870:Gene Expression; D006632:Histamine / Q000097:blood*; D006636:Histamine Release / Q000187:drug effects*; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology / Q000276:immunology / Q000378:metabolism / Q000628:therapy*; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000276:immunology; D011755:Pyrophosphatases / Q000235:genetics / Q000276:immunology; D060149:Tetraspanin 30 / Q000235:genetics / Q000276:immunology; D014862:Wasp Venoms / Q000627:therapeutic use*; D014863:Wasps
chemical_list: C554586:CD63 protein, human; C427944:ENPP3 protein, human; D060149:Tetraspanin 30; D014862:Wasp Venoms; D007073:Immunoglobulin E; D006632:Histamine; D010727:Phosphoric Diester Hydrolases; D011755:Pyrophosphatases