title: Collaborative study to establish the first international standard for quantitation of anti-HPA-1a.
abstract: OBJECTIVE
  This report describes the production of a freeze-dried preparation of pooled human plasma, containing immunoglobulin G (IgG) antibodies against the human platelet antigen 1a (HPA-1a). The material, coded 03/152, is proposed as an International Standard containing 100 arbitrary units of anti-HPA-1a for use in quantitative assays to determine the anti-HPA-1a activity in clinical samples.
  
  
  METHODS
  Plasma samples containing potent anti-HPA-1a were pooled and freeze dried in 1-ml ampoules. In addition, three individual plasma samples were selected which had varying levels of anti-HPA-1a activity. The anti-HPA-1a activity of these three samples was determined by using a variety of quantitative assays with the proposed standard as a reference.
  
  
  RESULTS
  An international collaborative study, which was part of the 2004 ISBT Platelet Immunology Workshop, involved 39 laboratories in 24 countries and showed that the anti-HPA-1a activity in three test samples could be reliably determined by using the proposed standard.
  
  
  CONCLUSIONS
  Laboratories can use this standard to measure the anti-HPA-1a activity in patient's samples. Further studies are required to determine the relationship between anti-HPA-1a activity and clinical outcome in patients with neonatal alloimmune thrombocytopenia (NAIT).
authors.affiliation: National Blood Service, Oxford, UK.
authors.forename: D
authors.initials: D
authors.lastname: Allen
authors.forename: P
authors.initials: P
authors.lastname: Rigsby
authors.forename: H
authors.initials: H
authors.lastname: Bessos
authors.forename: J
authors.initials: J
authors.lastname: Berry
authors.forename: D
authors.initials: D
authors.lastname: Wilson
authors.forename: W H
authors.initials: WH
authors.lastname: Ouwehand
authors.forename: S
authors.initials: S
authors.lastname: Urbaniak
authors.forename: P
authors.initials: P
authors.lastname: Metcalfe
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D016824:Antigens, Human Platelet / Q000276:immunology*; D001792:Blood Platelets / Q000166:cytology / Q000276:immunology; D001793:Blood Preservation / Q000379:methods* / Q000592:standards*; D015925:Cryopreservation; D005615:Freezing; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D007231:Infant, Newborn; D039661:Integrin beta3; D007391:International Cooperation; D017713:Platelet Transfusion / Q000379:methods; D013048:Specimen Handling; D013696:Temperature; D013921:Thrombocytopenia / Q000097:blood
chemical_list: D000911:Antibodies, Monoclonal; D016824:Antigens, Human Platelet; C061248:ITGB3 protein, human; D007074:Immunoglobulin G; D039661:Integrin beta3