Dataset Information

APRIL/BLyS Blockade Reduces Donor-specific Antibodies in Allosensitized Mice.

ABSTRACT:

Background

Highly sensitized candidates on the transplant waitlist remain a significant challenge, as current desensitization protocols have variable success rates of donor-specific antibody (DSA) reduction. Therefore, improved therapies are needed. A proliferation-inducing ligand (APRIL) and B-lymphocyte stimulator (BLyS) are critical survival factors for B-lymphocytes and plasma cells, which are the primary sources of alloantibody production. We examined the effect of APRIL/BLyS blockade on DSA in a murine kidney transplant model as a possible novel desensitization strategy.

Methods

C57BL/6 mice were sensitized with intraperitoneal (IP) injections of 2 × 10 BALB/c splenocytes. Twenty-one days following sensitization, animals were treated with 100 μg of BLyS blockade (B-cell activating factor receptor-immunoglobulin) or APRIL/BLyS blockade (transmembrane activator and calcium modulator and cyclophilin ligand interactor-immunoglobulin), administered thrice weekly for an additional 21 days. Animals were then euthanized or randomized to kidney transplant with Control Ig, BLyS blockade, or APRIL/BLyS blockade. Animals were euthanized 7 days posttransplant. B-lymphocytes and DSA of BLyS blockade only or APRIL/BLyS blockade-treated mice were assessed by flow cytometry, immunohistochemistry, and enzyme-linked immunospot.

Results

APRIL/BLyS inhibition resulted in a significant reduction of DSA by flow crossmatch compared with controls (P < 0.01). APRIL/BLyS blockade also significantly depleted IgM- and IgG-secreting cells and B-lymphocyte populations compared to controls (P < 0.0001). APRIL/BLyS blockade in transplanted mice also resulted in decreased B-lymphocyte populations; however, no difference in rejection rates were seen between groups.

Conclusions

APRIL/BLyS blockade with transmembrane activator and calcium modulator and cyclophilin ligand interactor-immunoglobulin significantly depleted B-lymphocytes and reduced DSA in this sensitized murine model. APRIL/BLyS inhibition may be a clinically useful desensitization strategy for sensitized transplant candidates.

SUBMITTER: Wilson NA

PROVIDER: S-EPMC6594891 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Publications

APRIL/BLyS Blockade Reduces Donor-specific Antibodies in Allosensitized Mice.

Wilson Nancy A NA Bath Natalie M NM Verhoven Bret M BM Ding Xiang X Boldt Brittney A BA Sukhwal Adarsh A Zhong Weixiong W Panzer Sarah E SE Redfield Robert R RR

Transplantation 20190701 7

<h4>Background</h4>Highly sensitized candidates on the transplant waitlist remain a significant challenge, as current desensitization protocols have variable success rates of donor-specific antibody (DSA) reduction. Therefore, improved therapies are needed. A proliferation-inducing ligand (APRIL) and B-lymphocyte stimulator (BLyS) are critical survival factors for B-lymphocytes and plasma cells, which are the primary sources of alloantibody production. We examined the effect of APRIL/BLyS blocka ...[more]

PMID: 30830041

Similar Datasets

Project description:Alloantibody represents a significant barrier in kidney transplant through the sensitization of patients prior to transplant through antibody mediated rejection (ABMR). APRIL BLyS are critical survival factors for mature B lymphocytes plasma cells, the primary source of alloantibody. We examined the effect of APRIL/BLyS blockade via TACI-Ig (Transmembrane activator calcium modulator cyclophilin lig interactor-Immunoglobulin) in a preclinical rodent model as treatment for both desensitization ABMR. Lewis rats were sensitized with Brown Norway (BN) blood for 21 days. Following sensitization, animals were then sacrificed or romized into kidney transplant (G4, sensitized transplant control); desensitization with TACI-Ig followed by kidney transplant (G5, sensitized + pre-transplant TACI-Ig); kidney transplant with post-transplant TACI-Ig for 21 days (G6, sensitized + post-transplant TACI-Ig); desensitization with TACI-Ig followed by kidney transplant post-transplant TACI-Ig for 21 days (G7, sensitized + pre- post-transplant TACI-Ig). Animals were sacrificed on day 21 post-transplant tissues were analyzed using flow cytometry, IHC, ELISPOT, RT-PCR. Sensitized animals treated with APRIL/BLyS blockade demonstrated a significant decrease in marginal zone non-switched B lymphocyte populations (p<0.01). Antibody secreting cells were also significantly reduced in the sensitized APRIL/BLyS blockade treated group. Post-transplant APRIL/BLyS blockade treated animals were found to have significantly less C4d deposition less ABMR as defined by Banff classification when compared to groups receiving APRIL/BLyS blockade before transplant or both before after transplant (p<0.0001). The finding of worse ABMR in groups receiving APRIL/BLyS blockade before both before after transplant may indicate that B lymphocyte depletion in this setting also resulted in regulatory lymphocyte depletion resulting in a worse rejection. Data presented here demonstrates that the targeting of APRIL BLyS can significantly deplete mature B lymphocytes, antibody secreting cells, effectively decrease ABMR when given post-transplant in a sensitized animal model.

Project description:Background and objectivesThe prognostic value of preformed donor-specific HLA antibodies (DSA), which are only detectable by sensitive methods, remains controversial for kidney transplantation.Design, setting, participants, & measurementsThe outcome of 4233 consecutive kidney transplants performed between 2012 and 2015 in 18 German transplant centers was evaluated. Most centers used a stepwise pretransplant antibody screening with bead array tests and differentiation of positive samples by single antigen assays. Using these screening results, DSA against HLA-A, -B, -C, -DRB1 and -DQB1 were determined. Data on clinical outcome and possible covariates were collected retrospectively.ResultsPretransplant DSA were associated with lower overall graft survival, with a hazard ratio of 2.53 for living donation (95% confidence interval [95% CI], 1.49 to 4.29; P<0.001) and 1.59 for deceased donation (95% CI, 1.21 to 2.11; P=0.001). ABO-incompatible transplantation was associated with worse graft survival (hazard ratio, 2.09; 95% CI, 1.33 to 3.27; P=0.001) independent from DSA. There was no difference between DSA against class 1, class 2, or both. Stratification into DSA <3000 medium fluorescence intensity (MFI) and DSA ≥3000 MFI resulted in overlapping survival curves. Therefore, separate analyses were performed for 3-month and long-term graft survival. Although DSA <3000 MFI tended to be associated with both lower 3-month and long-term transplant survival in deceased donation, DSA ≥3000 MFI were only associated with worse long-term transplant survival in deceased donation. In living donation, only strong DSA were associated with reduced graft survival in the first 3 months, but both weak and strong DSA were associated with reduced long-term graft survival. A higher incidence of antibody-mediated rejection within 6 months was only associated with DSA ≥3000 MFI.ConclusionsPreformed DSA were associated with an increased risk for graft loss in kidney transplantation, which was greater in living than in deceased donation. Even weak DSA <3000 MFI were associated with worse graft survival. This association was stronger in living than deceased donation.

Project description:Development of donor-specific human leukocyte antigen (HLA) antibodies (DSA) remains a major risk factor for graft loss following organ transplantation, where DSA are directed towards patches on the three-dimensional structure of the respective organ donor's HLA proteins. Matching donors and recipients based on HLA epitopes appears beneficial for the avoidance of DSA. Defining surface epitopes however remains challenging and the concepts underlying their characterization are not fully understood. Based on our recently implemented computational deep learning pipeline to define HLA Class I protein-specific surface residues, we hypothesized a correlation between the number of HLA protein-specific solvent-accessible interlocus amino acid mismatches (arbitrarily called Snowflake) and the incidence of DSA. To validate our hypothesis, we considered two cohorts simultaneously. The kidney transplant cohort (KTC) considers 305 kidney-transplanted patients without DSA prior to transplantation. During the follow-up, HLA antibody screening was performed regularly to identify DSA. The pregnancy cohort (PC) considers 231 women without major sensitization events prior to pregnancy who gave live birth. Post-delivery serum was screened for HLA antibodies directed against the child's inherited paternal haplotype (CSA). Based on the involved individuals' HLA typings, the numbers of interlocus-mismatched antibody-verified eplets (AbvEPS), the T cell epitope PIRCHE-II model and Snowflake were calculated locus-specific (HLA-A, -B and -C), normalized and pooled. In both cohorts, Snowflake numbers were significantly elevated in recipients/mothers that developed DSA/CSA. Univariable regression revealed significant positive correlation between DSA/CSA and AbvEPS, PIRCHE-II and Snowflake. Snowflake numbers showed stronger correlation with numbers of AbvEPS compared to Snowflake numbers with PIRCHE-II. Our data shows correlation between Snowflake scores and the incidence of DSA after allo-immunization. Given both AbvEPS and Snowflake are B cell epitope models, their stronger correlation compared to PIRCHE-II and Snowflake appears plausible. Our data confirms that exploring solvent accessibility is a valuable approach for refining B cell epitope definitions.

Project description:Due to the current organ shortage, living donor kidney transplantation is increasingly performed across HLA (human leukocyte antigen) or ABO antibody barriers. There is still uncertainty about the risk of antibody-mediated rejection (AMR) episodes, which may limit long-term graft survival. From March 2007 to December 2016, 58 sensitized living donor kidney transplant candidates were identified and 38 patients eventually included in the study: 36 patients (95%) had pre-transplant and pre-desensitization Luminex-detected donor-specific HLA antibodies (DSA), and 17/36 patients (47%) in addition had a positive crossmatch result. Two patients had no detectable DSA but a positive CDC B-cell crossmatch result. Patients were treated with pre- and post-transplant apheresis and powerful immunosuppression including the anti-CD20 antibody rituximab (N = 36) in combination with thymoglobulin (N = 20) or anti-IL2 receptor antibody (N = 18). The results of the 38 successfully desensitized and transplanted patients were retrospectively compared to the results of 76 matched standard-risk recipients. Desensitized patients showed patient and graft survival rates similar to that of standard-risk recipients (P = 0.55 and P = 0.16, respectively). There was a trend toward reduced death-censored graft survival in desensitized patients (P = 0.053) which, however, disappeared when the 34 patients who were transplanted after introduction of sensitive Luminex testing were analyzed (P = 0.43). The incidence of rejection episodes without borderline changes were in desensitized patients with 21% similar to the 18% in standard-risk patients (P = 0.74). Thirty-six patients had pre-transplant HLA class I and/or II DSA that were reduced by 85 and 81%, respectively, during pre-transplant desensitization (P < 0.001 for both). On day 360 after transplantation, 20 of 36 (56%) patients had lost their DSA. The overall AMR rate was 6% in these patients, but as high as 60% in 5 (14%) patients with persistent and de novo DSA during year 1; 2 (40%) of whom lost their graft due to AMR. Eleven (31%) patients with persistent DSA but without de novo DSA had an AMR rate of 18% without graft loss while one patient lost her graft without signs of AMR. Our desensitization protocol for pre-sensitized living donor kidney transplant recipients with DSA resulted in good graft outcomes with side effects and rejection rates similar to that of standard-risk recipients. Adequate patient selection prior to transplantation and frequent immunological monitoring thereafter is critical to minimize rejection episodes and subsequent graft loss.

Dataset Information

APRIL/BLyS Blockade Reduces Donor-specific Antibodies in Allosensitized Mice.

Background

Methods

Results

Conclusions

Publications

APRIL/BLyS Blockade Reduces Donor-specific Antibodies in Allosensitized Mice.

Similar Datasets

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