title: The relevance of HPA-15 antigen expression for anti-HPA-15 antibody detection.
abstract: BACKGROUND
  The HPA-15 antigen system is characterized by a low antigen expression on platelets. The antibodies against this antigen are implied in fetal/neonatal alloimmune thrombocytopenia (F/NAIT), post-transfusion purpura, and refractoriness to platelet transfusions. Detection of these antibodies appears to be related to the level of HPA-15 expression on the platelets used in the monoclonal antibody-specific immobilization of platelet antigen (MAIPA) assay.
  
  
  METHODS
  We performed genotyping of 300 healthy blood donors for HPA-15 by TaqMan real-time PCR technology, and the HPA-15 antigen expression was investigated in 13 HPA-15aa and 19 HPA-15bb individuals. We also investigated the relevance of HPA-15 antigen expression on donor platelets used in MAIPA for antibody detection in 223 multitransfused hematological patients and 271 women with suspected F/NAIT.
  
  
  RESULTS
  In Polish donors, the HPA-15a allele frequencies were lower than the HPA-15b (0.480 vs. 0.515). We identified three HPA-15 expression groups: high (36.7 ± 8.36 MFI - eight cases), medium (19.5 ± 6.2 MFI - 21 cases), and low (6.5 ± 5.9 MFI - three cases). The HPA-15 expression was stable over time. The HPA-15aa and HPA-15bb platelets with high antigen expression were used for anti-HPA-15 antibody detection; anti-HPA-15 antibodies were detected in 4/223 (1.8%) patients receiving multiple transfusions but in none of the 271 women with suspected F/NAIT. Further examination of the four sera by MAIPA with various platelets revealed the optical density in the assay to be closely related to the level of HPA-15 antigen expression.
  
  
  CONCLUSIONS
  Anti-HPA-15 antibody detection should be based on carefully selected platelets with high HPA-15 expression level.
authors.affiliation: Institute of Hematology and Transfusion Medicine, Warsaw, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Maślanka
authors.forename: H
authors.initials: H
authors.lastname: Michur
authors.forename: K
authors.initials: K
authors.lastname: Guz
authors.forename: A
authors.initials: A
authors.lastname: Wróbel
authors.forename: M
authors.initials: M
authors.lastname: Uhrynowska
authors.forename: A
authors.initials: A
authors.lastname: Misiak
authors.forename: A
authors.initials: A
authors.lastname: Ejduk
authors.forename: E
authors.initials: E
authors.lastname: Brojer
authors.forename: B
authors.initials: B
authors.lastname: Zupańska
mesh_terms: D000328:Adult; D000483:Alleles; D015703:Antigens, CD / Q000235:genetics* / Q000276:immunology*; D016824:Antigens, Human Platelet / Q000235:genetics* / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology / Q000378:metabolism; D058851:GPI-Linked Proteins / Q000235:genetics / Q000276:immunology; D005787:Gene Frequency; D005838:Genotype; D060005:Genotyping Techniques; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics* / Q000276:immunology*; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D016824:Antigens, Human Platelet; D001323:Autoantibodies; C120523:CD109 protein, human; D058851:GPI-Linked Proteins; D009363:Neoplasm Proteins