Anti-HLA donor-specific antibodies(DSA) identified by Luminex are questioned for excess in sensitivity and lack of prediction of clinical events after kidney transplantation(KT). We performed a retrospective study to evaluate if specific types of preformed DSA (class I or II or C1qfixing ones) have impact on graft survival.
Methods: KT performed 2006-2011 across a negative mixed-lympocytes CDC-crossmatch were included(n=355). Anti-HLA antibodies were tested using Luminex Lifecodes LifeScreen and LSA Class I/II assays. One Lambda commercial kits confirmed DSA before detection of C1q fixing antibodies with One Lambdas Single Antigens Beads and C1q screen kits.
Results: 66 patients with positive screening were tested for DSA; 28 pretransplant DSA+ KT with MFI>2000 were tested for C1q fixation. They were 75% female, 64.3% reKT with a high rate of biopsy-proven acute rejection(35.7%) and acute antibody-mediated-rejection(AMR=25%). Early graft loss (<3 months post-KT) was 14.3% and global loss=21.4% at 30 months follow-up. Renal function for surviving grafts was good (median last SCr=1.27 mg/dl).
DSA were C1q+ in 15 patients and C1q- in 13 without significant differences in demographics, acute rejection(33.3 vs 46.2%), acute AMR(26.7% vs 30.8%), graft loss(20 vs 23.1%) or renal function at follow-up. Immunodominant DSAC1q+ had higher MFI than C1q-DSA (12190+7141vs5630+4747, p=0.008). Postransplant monitoring showed C1q+ DSA class-II persisted postKT more frequently than C1q- DSA class-II (60 vs 30.8%) without statistical significance.
Ten patients had anti-HLA DSA class-I with/without class-II and 18 patients only class-II. Patients with class-I suffered more AMR than class-II (50 vs 16.7%, p=0.06). They had significant worse graft survival over time (p=0.01); four early graft losses (<3mo postKT) occurred in DSA-I group. Capacitiy of DSA I to fix C1q did not correlate to AMR (50% in C1q+DSAI and C1q-DSAI) or graft loss (C1q+ 50% vs. C1q- 33%). Postransplant persistence of DSA class-II was more frequent than of DSA-I (66.7 vs 16.7%,p=0.06).
Conclusion: C1q testing in pretransplant sera with DSA was unable to predict antibody-mediated rejection or graft loss, but the presence of DSA class-I compared to class-II did. PreKT DSA-I C1q- can mediate AMR and graft loss.
To cite this abstract in AMA style:Crespo M, Torío A, Mas V, Perez-Saez M, Mir M, Faura A, Checa M, Pascual J. Detection of Anti-HLA Class I but Not C1q-Fixing Donor-Specific Antibodies before Kidney Transplantation Predicts Early Graft Loss [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/detection-of-anti-hla-class-i-but-not-c1q-fixing-donor-specific-antibodies-before-kidney-transplantation-predicts-early-graft-loss/. Accessed September 22, 2020.
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