title: Rapid whole blood flow cytometric test to detect ICOS deficiency in patients with common variable immunodeficiency.
abstract: OBJECTIVE
  Common variable immunodeficiency (CVID) is the most common primary immunodeficiency. With respect to underlying defects it comprises a heterogeneous group of deficiencies. For some patients, distinct phenotypical abnormalities have been described, e.g. partial CD40L deficiency or complete ICOS deficiency. For the diagnosis of CD40L deficiency, a rapid whole blood flow cytometric method has been described several years ago. We aimed to determine if the same method can be used to diagnose ICOS deficiency.
  
  
  METHODS
  Whole blood from 8 healthy volunteers was stimulated for 4 and 20 h with phorbol 12-myristate 13-acetate (PMA) and ionomycin. Induction of ICOS expression was analyzed on CD8-CD3+ lymphocytes using three-color flow cytometry. Blood from a patient with diagnosed ICOS deficiency was also analyzed.
  
  
  RESULTS
  Whole-blood stimulation with PMA and ionomycin for 20 h resulted in a significant induction of ICOS expression on CD8-CD3+ lymphocytes in healthy volunteers. Four-hour incubation also demonstrated ICOS upregulation but to a much lower extent. In CD8-CD3+ lymphocytes from an ICOS-deficient patient, no ICOS expression could be induced following 20 h of stimulation.
  
  
  CONCLUSIONS
  ICOS expression can be analyzed using a rapid whole blood flow cytometric test.
authors.affiliation: Institute of Medical Immunology, University Hospital, Campus Charité Mitte, Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Bunk
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Dittrich
authors.forename: Ilka
authors.initials: I
authors.lastname: Schulze
authors.forename: Julia
authors.initials: J
authors.lastname: Horn
authors.forename: Kathrin
authors.initials: K
authors.lastname: Schmolke
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Volk
authors.forename: Volker
authors.initials: V
authors.lastname: Wahn
authors.forename: Conny
authors.initials: C
authors.lastname: Höflich
mesh_terms: D015703:Antigens, CD / Q000097:blood; D000945:Antigens, Differentiation, T-Lymphocyte / Q000097:blood* / Q000378:metabolism; D017252:CD3 Complex / Q000097:blood; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D017074:Common Variable Immunodeficiency / Q000097:blood* / Q000473:pathology; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D060889:Inducible T-Cell Co-Stimulator Protein; D015759:Ionomycin / Q000494:pharmacology; D037181:Lectins, C-Type; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D060889:Inducible T-Cell Co-Stimulator Protein; D015759:Ionomycin; D037181:Lectins, C-Type; D013755:Tetradecanoylphorbol Acetate; D000099192:CD69 Antigens; C556692:ICOS protein, human