title: Factors influencing HLA sensitization in implantable LVAD recipients.
abstract: BACKGROUND
  Patients bridged to transplantation (TX) with the implantable left ventricular assist device (LVAD) may be at increased risk for the development of panel-reactive antibodies (PRA) during support.
  
  
  METHODS
  To investigate that, we evaluated 60 patients who received the HeartMate LVAD at our institution, of whom 53 had PRA results available for analysis. T lymphocyte PRA levels were examined before LVAD, at the peak PRA level during LVAD support (PEAK), and just before TX. A PRA level more than 10% was considered indicative of sensitization against HLA antigens.
  
  
  RESULTS
  The only factor that had a significant effect on PRA levels before LVAD was patient's sex (1.3% for men versus 7.4% for women; p = 0.005). During LVAD support, peak PRA levels increased significantly and the sex-associated differences were no longer evident (33.3% men, 34.3% women; not significant). At the time of TX, PRAs decreased to 10.9% (men) and 7.0% (women) (not significant). We examined the influence of blood products received before TX on PRA levels. Patients who received less than the median number of total units (<median) had lower peak PRA values (22.3% versus 49.2%; p = 0.01) and TX PRA values (3.5% versus 22.1%; p = 0.02) than those receiving more than the median (>median). When examined by the type of blood product, only the number of platelet transfusions significantly increased the peak PRA (<median: 24% versus >median: 46.9%; p = 0.03). Patients who received blood that was leukocyte-depleted tended to have lower TX PRA levels (2.9%) compared with those who did not (13.9%, p = 0.18). Forty-two patients were successfully bridged to TX, with three early and two late deaths after TX. Whereas 39 patients received transplants without intervention, 3 were treated by plasmapheresis with a 77% reduction in their HLA antibody levels at TX as measured by flow cytometry.
  
  
  CONCLUSIONS
  Patients with the implantable LVAD are at significant risk for the development of anti-HLA antibodies during support. Although this sensitization is often transient, intervention using plasmapheresis may be useful for some patients.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, The Cleveland Clinic Foundation, Ohio 44195-5066, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Massad
authors.forename: D J
authors.initials: DJ
authors.lastname: Cook
authors.forename: S K
authors.initials: SK
authors.lastname: Schmitt
authors.forename: N G
authors.initials: NG
authors.lastname: Smedira
authors.forename: J F
authors.initials: JF
authors.lastname: McCarthy
authors.forename: R L
authors.initials: RL
authors.lastname: Vargo
authors.forename: P M
authors.initials: PM
authors.lastname: McCarthy
mesh_terms: D000328:Adult; D001803:Blood Transfusion; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D006353:Heart-Assist Devices; D006650:Histocompatibility Testing; D006801:Humans; D007518:Isoantibodies / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012737:Sex Factors
chemical_list: D006680:HLA Antigens; D007518:Isoantibodies