title: Single-antigen-expressing cell lines are excellent tools for detecting human leukocyte antigen-C-reactive antibodies in kidney transplant recipients.
abstract: BACKGROUND
  Human leukocyte antigen (HLA)-C is expressed on nucleated cells and platelets in lower levels than HLA-A,B, and its antigens are in linkage disequilibrium with HLA-B antigens. Therefore, HLA-C antibody detection is difficult. The authors questioned whether HLA-C could serve as a target in clinical kidney transplantation using a newly developed assay.
  
  
  METHODS
  Flow cytometry was performed with sera from patients (n=34) awaiting a kidney retransplant using nine cell lines expressing a single HLA-C antigen (single-antigen lines [SAL]).
  
  
  RESULTS
  The SAL were validated with HLA-C-specific alloantisera and human monoclonal antibodies against HLA-A, -B, and -C. The results were in agreement with the specificities previously reported. Exceptions, because of new HLA-C specificities used here, could be explained by epitope sharing between the antigens. With respect to patient sera, 15 of the 34 patients tested (44%) showed serum reactivity toward one or more HLA-C SAL.
  
  
  CONCLUSIONS
  In contrast to peripheral blood lymphocytes, SAL are excellent targets for detecting HLA-C-reactive alloantibodies by flow cytometry. This preliminary analysis revealed that HLA-C-reactive antibodies are frequently present in sera of retransplant patients, serving as possible targets in clinical transplantation.
authors.affiliation: Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Yvonne M
authors.initials: YM
authors.lastname: Zoet
authors.forename: Chantal
authors.initials: C
authors.lastname: Eijsink
authors.forename: Radka
authors.initials: R
authors.lastname: Böhmová
authors.forename: Marian D
authors.initials: MD
authors.lastname: Witvliet
authors.forename: Marrie J
authors.initials: MJ
authors.lastname: Kardol
authors.forename: Marry E I
authors.initials: ME
authors.lastname: Franke
authors.forename: Frans H J
authors.initials: FH
authors.lastname: Claas
authors.forename: Arend
authors.initials: A
authors.lastname: Mulder
authors.forename: Ilias I N
authors.initials: II
authors.lastname: Doxiadis
mesh_terms: D000906:Antibodies / Q000097:blood; D000941:Antigens / Q000276:immunology*; D015415:Biomarkers / Q000032:analysis; D002460:Cell Line; D000939:Epitopes / Q000032:analysis; D015236:HLA-C Antigens / Q000276:immunology*; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology*; D007962:Leukocytes / Q000276:immunology*; D018579:Patient Selection; D015203:Reproducibility of Results
chemical_list: D000906:Antibodies; D000941:Antigens; D015415:Biomarkers; D000939:Epitopes; D015236:HLA-C Antigens