Human leukocyte antigen mismatch and circulating donor-specific antibodies predict graft loss after kidney transplantation: A retrospective study from Campania region - Italy.

Donor-specific antibodies (DSA) are an established biomarker predicting antibody-mediated rejection, as the leading cause of graft loss after kidney transplantation. Furthermore, human leukocyte antigen (HLA) matching offers a more precise assessment of donor-recipient HLA compatibility and may prevent more effectively sensitization against allograft tissue. Indeed, increased number of HLA mismatches (MM) is significantly associated with a higher risk of immunological rejection, de novo DSA (dnDSA) development, and graft failure. Over the last decade, a comprehensive approach to optimize kidney matching and monitor transplant recipients for acute and chronic graft dysfunction was the goal for the success of the kidney transplantation. In our long-term retrospective study, we have found that pre- and post-transplantation HLA antibodies were significantly associated with de novo dnDSA occurrence (pre-transplant HLA Class I antibodies p = 0.039p < 0.05; pre-transplant HLA Class II antibodies p = 0.011p < 0.05; post-transplant HLA Class I non-DSA antibodies p < 0.01; post-transplant HLA Class II non-DSA antibodies p < 0.01). In addition, HLA MM at locus A (hazard ratio (HR), 2.44; 95 % confidence interval (CI): 1.15-5.16; p = 0.01 hazard ratio (HR), 2.33; 95 % confidence interval (CI):1.132-4.805; p = 0.02) and DSA Class I (HR, 10.24; 95 % CI: 1.44-72.62; p = 0.02 HR, 5.539; 95 % CI: 1.264-24.272; p = 0.02) appeared to be significant predictors of poorer graft survival. Our investigation demonstrates the long medium-term experience of DSA development occurrence in patients with after kidney transplantation in Campania region - Italy.

Strozziero M ，Costa D ，Benincasa G ，Grimaldi V ，De Rosa P ，Valeriani G ，Santangelo M ，Carrano R ，Pacilio S ，Cacciatore F ，Napoli C ... -  《-》

Eplet Mismatch Load and De Novo Occurrence of Donor-Specific Anti-HLA Antibodies, Rejection, and Graft Failure after Kidney Transplantation: An Observational Cohort Study.

In kidney transplantation, evaluating mismatches of HLA eplets-small patches of surface-exposed amino acids of the HLA molecule-instead of antigen mismatches might offer a better approach to assessing donor-recipient HLA incompatibility and improve risk assessment and prediction of transplant outcomes. To evaluate the effect of number of eplet mismatches (mismatch load) on de novo formation of donor-specific HLA antibodies (DSAs) and transplant outcomes, we conducted a cohort study that included consecutive adult kidney recipients transplanted at a single center from March 2004 to February 2013. We performed retrospective high-resolution genotyping of HLA loci of 926 transplant pairs and used the HLAMatchmaker computer algorithm to count HLA eplet mismatches. De novo DSAs occurred in 43 (4.6%) patients. Multivariable analysis showed a significant independent association between antibody-verified eplet mismatch load and de novo DSA occurrence and graft failure, mainly explained by DQ antibody-verified eplet effects. The association with DQ antibody-verified eplet mismatches was linear, without a safe threshold at which de novo DSA did not occur. Odds for T cell- or antibody-mediated rejection increased by 5% and 12%, respectively, per antibody-verified DQ eplet mismatch. Eplet mismatches in HLA-DQ confer substantial risk for de novo DSA formation, graft rejection, and graft failure after kidney transplantation. Mismatches in other loci seem to have less effect. The results suggest that antibody-verified HLA-DQ eplet mismatch load could be used to guide personalized post-transplant immunosuppression. Adoption of molecular matching for DQA1 and DQB1 alleles could also help to minimize de novo DSA formation and potentially improve transplant outcomes.

Senev A ，Coemans M ，Lerut E ，Van Sandt V ，Kerkhofs J ，Daniëls L ，Driessche MV ，Compernolle V ，Sprangers B ，Van Loon E ，Callemeyn J ，Claas F ，Tambur AR ，Verbeke G ，Kuypers D ，Emonds MP ，Naesens M ... -  《-》

Characteristics of donor-specific anti-HLA antibodies and outcome in renal transplant patients treated with a standardized induction regimen.

Pre-transplant donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) have been associated with antibody-mediated rejection (AMR) and early kidney allograft loss. Uncertainties remain regarding the general applicability of these findings and the optimal induction therapy in DSA-positive patients. Pre-transplant sera from 174 patients receiving a crossmatch-negative kidney transplant were retrospectively analysed for DSA using Luminex technology. DSA with mean-fluorescence intensity (MFI) values above 500 were considered positive. All recipients received basiliximab induction and tacrolimus-based maintenance immunosuppression. DSA were monitored post-transplantation in patients with pre-transplant DSA. Antibody results were correlated with the incidence of rejection and graft loss. In total, 61/174 patients had pre-transplant DSA. We found a strong correlation between the presence of DSA against class I and II HLA and DSA MFI greater than 10 000. Both DSA patterns independently predicted an increased risk of early AMR (odds ratio 4.24 and 4.75, respectively, P < 0.05). The risk for AMR in patients with intermediate MFI (3000-10 000) gradually increased with increasing MFI but group sizes were too small to allow for final conclusions. The risk for AMR was comparable to nonsensitized patients in patients with only class I or II HLA-DSA or MFI below 3000. 5-year allograft survival was lowest in patients with simultaneous presence of class I and II HLA-DSA and MFI above 10 000 (45%) but was comparable between patients with only HLA class I or II or no DSA (90.0, 90.0 and 88.1%, respectively). AMR was the only independent predictor of graft loss. Undetectable DSA 14 days post-transplant predicted excellent long-term outcome. . The favourable outcome in the majority of DSA-positive patients despite non-depleting antibody induction and the poor outcome in patients with class I and II HLA-DSA and high DSA strength call for a differentiated therapeutic approach in this patient population.

Zecher D ，Bach C ，Staudner C ，Böger CA ，Bergler T ，Banas B ，Spriewald BM ... -  《-》

Pretransplant angiotensin II type 1-receptor antibodies are a risk factor for earlier detection of de novo HLA donor-specific antibodies.

Angiotensin II type 1 receptor antibodies (AT1Rabs) have been associated with significantly reduced graft survival. Earlier graft loss has been observed in patients who had pretransplant AT1Rabs and posttransplant donor-specific antibodies (DSA). The main goal of this retrospective cohort study was to examine the association between AT1Rabs and the time period to detection of de novo human leukocyte antigen (HLA-DSA) posttransplantation in living donor kidney transplant recipients (KTR). The analysis included 141 KTRs. Pretransplant frozen serum samples were tested for AT1Rabs by ELISA and HLA-DSA by SAB (Luminex) at both the pre- and post-KT time points. The median AT1Rab level was 9.13 U (interquartile range 5.22-14.33). After a mean follow-up period of 3.55 years, 48 patients were found to harbour de novo HLA-DSAs. The presence of AT1Rabs [hazard ratio (HR) 1.009, 95% confidence interval (CI) 1.002-1.01, P = 0.010], male-to-male transplantation (HR 2.57, 95% CI 1.42-4.67, P = 0.002) and antecedent borderline changes or acute cellular rejection (ACR) (HR 2.47, 95% CI 1.29-4.75, P = 0.006) were significantly associated with de novo DSA detection. A dose-dependent association between AT1Rab levels (<10 U, 10.1-16.9 U, 17-29.9 U and >30 U) and de novo DSA detection was observed (log-rank P = 0.0031). After multivariate analysis of AT1Rab levels (continuous variable), AT1Rabs >30 U, male-to-male transplantation, donor age, higher class I percentage of Panel Reactive Antibody and antecedent borderline changes or ACR remained as independent significant risk factors for the detection of de novo DSAs. The findings suggest that higher levels of pretransplant circulating antibodies against AT1R (>30 U) in kidney graft recipients constitute an independent risk factor for earlier de novo HLA-DSA detection during the posttransplant period.

Cuevas E ，Arreola-Guerra JM ，Hernández-Méndez EA ，Salcedo I ，Castelán N ，Uribe-Uribe NO ，Vilatobá M ，Contreras-Saldívar AG ，Sánchez-Cedillo AI ，Ramírez JB ，de Rungs D ，Granados J ，Morales-Buenrostro LE ，Alberú J ... -  《-》

Donor-Recipient Matching Based on Predicted Indirectly Recognizable HLA Epitopes Independently Predicts the Incidence of De Novo Donor-Specific HLA Antibodies Following Renal Transplantation.

De novo donor-specific HLA antibodies (dnDSA) are recognized as a risk factor for premature allograft failure. Determinants of DSA specificity are generated via the indirect allorecognition pathway. Here, we present supportive data for the relevance of predicted indirectly recognizable HLA epitopes (PIRCHE) to predict dnDSA following kidney transplantation. A total of 2787 consecutive kidney transplants performed between 1995 and 2015 without preformed DSA have been analyzed. De novo DSA were detected by single antigen bead assay. HLA epitope mismatches were determined by the HLAMatchmaker and PIRCHE approach and correlated in uni- and multivariate analyses with 10-year allograft survival and incidence of dnDSA. The PIRCHE-II score moderately predicted allograft survival. However, the predictive value of elevated PIRCHE-II scores >9 for the incidence of dnDSA was statistically significant (p < 0.001). In a multivariate Cox regression analysis adjusted for antigen mismatch and HLAMatchmaker epitopes, the PIRCHE-II score could be identified as an independent risk factor for dnDSA. The PIRCHE-II score independently from the antigen mismatch and HLAMatchmaker epitopes could be revealed as being a strong predictor for dnDSA. PIRCHE may help to identify acceptable mismatches with decreased risk of dnDSA and thus improve long-term renal allograft survival.

Lachmann N ，Niemann M ，Reinke P ，Budde K ，Schmidt D ，Halleck F ，Pruß A ，Schönemann C ，Spierings E ，Staeck O ... -  《-》