title: Effect of Different Sensitization Events on HLA Alloimmunization in Kidney Transplantation Candidates.
abstract: BACKGROUND
  HLA alloimmunization is caused by sensitization events (SEs), such as transfusion, pregnancy, or previous organ transplantation, and the effects of particular SEs have not been thoroughly studied. Our aim was to evaluate how each SE affected HLA alloimmunization by considering Luminex assays.
  
  
  METHODS
  Sera from 722 kidney transplantation candidates were screened per protocol by means of Luminex assays to determine the presence of anti-HLA class I/II antibodies; positive sera underwent single-antigen assay to determine the presence of specific antibodies against HLA A, B, C, DR, DQ, DP loci (positivity if median fluorescence intensity values were >1,000). The effect of each SE was analyzed considering only patients exposed to 1 kind of sensitization.
  
  
  RESULTS
  In the 453 candidates with ≥1 SE, anti-HLA class I positivity rates were significantly higher in patients with previous transfusion (18.9%; P = .014), pregnancy (38.3%; P < .001) or transplant (75%; P < .001) compared with those with no SE (similar results for class II). The strength (median fluorescence intensity) of specific antibodies was significantly higher in patients with previous transplantation than in those with previous transfusion for HLA-A (8,017 vs 2,302; P = .02), HLA-B (7,765 vs 2,901; P = .018), and HLA-DR (9,835 vs 2,060; P = .003). Other anti-HLA antibody strengths were similar between patients with previous pregnancy or transplantation.
  
  
  CONCLUSIONS
  Presence of any SE analyzed was associated with a higher prevalence of anti-HLA antibodies for class I ± II compared with nonsensitized patients. Transplantation had the strongest immunization effect on both classes, followed by pregnancy and then transfusion.
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal. Electronic address: bannyel@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Lopes
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: T
authors.initials: T
authors.lastname: Barra
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Malheiro
authors.affiliation: Centro do Sangue e Transplantação do Porto, Porto, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Tafulo
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Martins
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Almeida
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Pedroso
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Dias
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Castro Henriques
authors.affiliation: Nephrology and Kidney Transplantation Department, Centro Hospitalar do Porto, Hospital de Santo António, Porto, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Cabrita
mesh_terms: D001323:Autoantibodies / Q000276:immunology*; D005260:Female; D006084:Graft Rejection / Q000276:immunology / Q000517:prevention & control*; D015235:HLA-B Antigens / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology*; D006801:Humans; D007114:Immunization / Q000379:methods*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D012189:Retrospective Studies
chemical_list: D001323:Autoantibodies; D015235:HLA-B Antigens; D006684:HLA-DR Antigens