Preformed donor-specific antibodies do not affect the 1-year allograft survival in living donor liver transplantation

Impact of Preformed Donor-specific Antibodies in Comparison to ABO Incompatibility in Living Donor Liver Transplantation: A Propensity Score-Matched Analysis

BACKGROUND

Immunological factors play a pivotal role in the outcomes of solid organ transplantation. We aimed to elucidate the effects of donor-specific antibodies (DSAs) and ABO compatibility on living donor liver transplantation (LDLT) outcomes.

METHODS

A retrospective analysis was conducted on 584 LDLT recipients from 2015 to 2020. The recipients were stratified into 3 groups: ABO-compatible recipients without DSAs (group 1), ABO-compatible recipients with DSAs (group 2), and ABO-incompatible recipients without DSAs (group 3). Propensity score matching was used for balanced comparisons.

RESULTS

In the matched comparisons, group 2 exhibited a higher incidence of T cell-mediated rejection compared with group 1 (22.7% versus 4.5%, P  = 0.030). Despite this, the 5-y survival rates were similar between groups 1 and 2 (81.6% versus 95.5%, P  = 0.085). Group 3, in comparison with group 1, showed elevated rates of cytomegalovirus infection (23.2% versus 7.3%, P  = 0.008), T cell-mediated rejection (28.0% versus 7.3%, P  = 0.001), and antibody-mediated rejection (13.4% versus 0%, P  = 0.001). However, the survival rates were comparable between group 3 and group 1 (82.0% versus 86.5%, P  = 0.220, respectively). Comparisons between group 2 and group 3 did not reveal significant differences in postoperative outcomes or survival rates ( P  > 0.05).

CONCLUSIONS

DSA positivity and ABO incompatibility contribute to distinct posttransplant complications in LDLT. The integrated consideration of both factors in pretransplant assessment may enhance risk stratification and inform tailored interventions. Further research is required to corroborate these findings and provide mechanistic insights.

The fate of anti-HLA antibodies following liver transplantation

Introduction

Liver transplant recipients may have pre-formed anti-HLA antibodies directed to mismatched HLA of the liver donor (donor specific antibodies, DSA) or not directed to the liver donor (non-donor specific, non-DSA). We observed the fate of these antibodies (DSA and non-DSA) at 12 months after transplant.

Methods

Patients transplanted between 4/2015 and 12/2018 (N = 216) who had anti-HLA antibody measurements at both transplant and 12 months posttransplant (N = 124) and with DSAs at transplant (N = 31) were considered informative for a paired analysis of the natural history of DSA and non-DSA following liver transplantation.

Results

Class I DSAs and non-DSAs decreased between transplant and 12 months; however, Class I DSAs essentially disappeared by 12 months while Class I non-DSAs did not. Anti-HLA Class II DSAs performed differently. While there was a significant drop in values between transplant and 12 months, these antibodies mostly persisted at a low level.

Discussion

Our study demonstrated a significant difference in the kinetics of DSA compared to non-DSA following liver transplantation, most profoundly for anti-HLA Class I antibodies. Class I DSAs were mostly absent at 12 months while Class II DSAs persisted, although at lower levels. The mechanisms of reduction in anti-HLA antibodies following liver transplantation are not completely understood and were not pursued as a part of this study. This detailed analysis of Class I and Class II DSAs and non-DSAs represents and important study to explore the change in antibodies at one year from liver transplantation.

Factors associated with rituximab-mediated B cell depletion in ABO-incompatible adult living donor liver transplantation

Background

Pretransplant therapies such as rituximab and plasmapheresis have led to an increase in ABO-incompatible (ABOi) living donor liver transplantation (LDLT), thus helping to overcome organ shortages. This study evaluated the changes in anti-A/B titers and CD19 levels over time in patients undergoing ABOi LT and aimed to understand the effect of single-nucleotide polymorphisms (SNPs) in Fc gamma receptor (FcγR) on rituximab therapy.

Methods

Two SNPs of FCGR2A (131H/R) and FCGR3A (158F/V) were identified. The clinical data on 44 patients who underwent ABOi LDLT between May 2019 and October 2021 at Seoul National University Hospital were reviewed retrospectively.

Results

Following desensitization with rituximab and subsequent LDLT, the anti-A/B titer recovered within 1 week, but decreased thereafter. The CD19 level increased at 3 months after LT. The genotyping data for FCGR3A (158F/V) indicated that two patients had the V/V genotype, and 42 had the F/V genotype. In the genotyping data for FCGR2A (131H/R), 21 patients had the H/H genotype, three had the R/R genotype, and 20 had the H/R genotype. However, there were no significant differences in anti-A/B and CD19 levels, bacteremia rates, T cell-mediated rejection, antibody-mediated rejection, or the survival rate among the FCGR2A types.

Conclusions

There were significant changes in the anti-A/B titers and CD19 levels over time in each patient after ABOi LDLT. The difference in outcomes following LT according to the FcγR SNP type for rituximab was unclear. Further studies with larger sample sizes are needed to confirm the effect of FcγR SNPs on rituximab therapy.

Clinical recommendations for posttransplant assessment of anti-HLA (Human Leukocyte Antigen) donor-specific antibodies: A Sensitization in Transplantation: Assessment of Risk consensus document

Although anti-HLA (Human Leukocyte Antigen) donor-specific antibodies (DSAs) are commonly measured in clinical practice and their relationship with transplant outcome is well established, clinical recommendations for anti-HLA antibody assessment are sparse. Supported by a careful and critical review of the current literature performed by the Sensitization in Transplantation: Assessment of Risk 2022 working group, this consensus report provides clinical practice recommendations in kidney, heart, lung, and liver transplantation based on expert assessment of quality and strength of evidence. The recommendations address 3 major clinical problems in transplantation and include guidance regarding posttransplant DSA assessment and application to diagnostics, prognostics, and therapeutics: (1) the clinical implications of positive posttransplant DSA detection according to DSA status (ie, preformed or de novo), (2) the relevance of posttransplant DSA assessment for precision diagnosis of antibody-mediated rejection and for treatment management, and (3) the relevance of posttransplant DSA for allograft prognosis and risk stratification. This consensus report also highlights gaps in current knowledge and provides directions for clinical investigations and trials in the future that will further refine the clinical utility of posttransplant DSA assessment, leading to improved transplant management and patient care.

Refractory Acute Antibody Mediated Rejection in Liver Transplant After Desensitization of Preformed Donor Specific Antibody-Validity of Bortezomib and Everolimus: A Case Report

Here, we report a case of living donor liver transplantation (LDLT) complicated with severe acute antibody-mediated rejection (aAMR), although desensitization was performed for preformed donor-specific anti-human leukocyte antigen antibody (DSA). LDLT was performed in a 59-year-old woman with alcoholic cirrhosis with a graft from her 60-year-old husband as a living donor. She had reproductive history of 4 gravidity and parity with her husband. Preoperative serologic studies showed positive complement-dependent cytotoxic crossmatch and anti-human leukocyte antigen-A26 antibody was identified as DSA. Desensitization for preformed DSA with rituximab and plasma exchange was performed before LDLT. We decided to perform LDLT using her husband right liver as living donor graft since the DSA mean fluoro-intensity was down to negative range. The immunosuppressive regimen was comprised with steroid and tacrolimus. However, the recipient developed acute cellular rejection on day 5 after LDLT, followed by severe aAMR. Re-administration of rituximab followed by 4 courses of plasma exchange failed to treat aAMR. The DSA mean fluoro-intensity was successfully suppressed after bortezomib was administered however impaired serologic liver function test and cholestasis were remained. The liver function test and cholestasis in the graft were improved after Everolimus was administered. The recipient was discharged on postoperative day 196. In conclusion, we report a case of LDLT who developed aAMR after desensitization of preformed DSA and was successfully treated with intensive therapy with bortezomib and everolimus.

Antibody-mediated rejection of the liver allograft: An update and a clinico-pathological perspective

Antibody-mediated rejection after liver transplantation is an under-recognised cause of allograft injury. While definitions of acute and chronic antibody-mediated rejection have increased clinical awareness, timely identification and management of antibody-mediated rejection remain difficult because of complexities in diagnosis and histopathology, lack of treatment protocols, and unclear long-term outcomes. While recent cohort studies assessing the importance of donor-specific antibodies have aided in its diagnosis, literature on the treatment of antibody-mediated rejection in liver transplantation remain limited to case reports and small series. Further increasing the awareness and timely recognition of antibody-mediated rejection post-liver transplantation is crucial in order to stimulate future research and the development of protocols for its diagnosis and treatment. This review will summarise recent advances in the clinical diagnosis and treatment of antibody-mediated rejection in liver transplantation, as well as some of the histopathologic features (on liver biopsy tissue) of acute and chronic antibody-mediated rejection.

Immunosuppression in liver and intestinal transplantation

Immunosuppression handling plays a key role in the early and long-term results of transplantation. The development of multiple immunosuppressive drugs led to numerous clincial trials searching to reach the ideal regimen. Due to heterogeneity of the studied patient cohorts and flaws in many, even randomized controlled, study designs, the answer still stands out. Nowadays triple-drug immunosuppression containing a calcineurin inhibitor (preferentially tacrolimus), an antimetabolite (using mycophenolate moffettil or Azathioprine) and short-term steroids with or without induction therapy (using anti-IL2 receptor blocker or anti-lymphocytic serum) is the preferred option in both liver and intestinal transplantation. This chapter aims, based on a critical review of the definitions of rejection, corticoresistant rejection and standard immunosuppression to give some reflections on how to reach an optimal immunosuppressive status and to conduct trials allowing to draw solid conclusions. Endpoints of future trials should not anymore focus on biopsy proven, acute and chronic, rejection but also on graft and patient survival. Correlation between early- and long-term biologic, immunologic and histopathologic findings will be fundamental to reach in much more patients the status of operational tolerance.

Rituximab Desensitization in Liver Transplant Recipients With Preformed Donor-specific HLA Antibodies: A Japanese Nationwide Survey

Background.

The significance of preformed donor-specific anti-HLA antibodies (DSAs) in liver transplant recipients is controversial. Moreover, there has been no established desensitization protocol for DSA-positive recipients.

Methods.

A Japanese nationwide survey was performed to investigate the clinical practice among preformed DSA-positive patients with special reference to rituximab desensitization.

Results.

There was a total of 47 cases, including 2 pediatric cases, in which rituximab (287 ± 159 mg [319 (50–916)/m²]) was administered to desensitize preformed DSA. The decision for the indication of rituximab desensitization was based on a single-antigen assay in the majority of cases (83%, 39/47), and the most frequent protocol was rituximab monotherapy (n = 12) followed by quadruple treatment with rituximab tacrolimus, mycophenolate mofetil, and plasmapheresis (n = 11). The overall 1-, 3-, and 5-y graft and patient survival rates among adult patients were 85%, 83%, 83%, and 81%, 77%, 74%, respectively, while neither graft loss nor death was observed in the 2 pediatric cases. The 1-, 3-, and 12-mo cumulative incidence of antibody-mediated rejection (AMR) was 11%, 13%, and 13%, respectively. The incidence of AMR was significantly higher in the lower rituximab dose group than in the higher rituximab dose group (cutoff 300 mg/m², 4% versus 24%, P = 0.041). The rate of infusion-related adverse drug reactions (ADRs) was 4.4%, and all ADRs were mild and self-limiting. A total of 99 ADRs among 27 patients were reported, none of which were severe adverse events associated with rituximab.

Conclusions.

The rituximab induction was well tolerated among DSA-positive liver transplant recipients with a satisfactory outcome. A rituximab dose >300 mg/m² was observed to achieve less incidence of the development of AMR.

Autoantibodies to LG3 are associated with poor long-term survival after liver retransplantation

Autoantibodies are detrimental to the survival of organ transplantation. We demonstrated that Angiotensin II Type I Receptor agonistic autoantibodies (AT1R-AA) were associated with poor outcomes after liver retransplantation. To examine the effect of other autoantibodies, we studied a retrospective cohort of 93 patients who received a second liver transplant. Pre-retransplant sera were tested with Luminex-based solid-phase assays. Among 33 tested autoantibodies, 15 were significantly higher in 48 patients who lost their regrafts than 45 patients whose regrafts were still functioning. Specifically, patients with autoantibodies to the C-terminal laminin-like globular domain of Perlecan (LG3) experienced significantly worse regraft survival (p = .002) than those with negative LG3 autoantibodies (LG3-A). In multivariate analysis, LG3-A (HR = 2.35 [1.11-4.98], p = .027) and AT1R-AA (HR = 2.09 [1.07-4.10], p = .032) remained significant predictors of regraft loss after adjusting for recipient age and sex. There were synergistic deleterious effects on regraft survival in patients who were double-positive for LG3-A and donor-specific antibody (DSA) (HR = 5.26 [2.15-12.88], p = .001), or LG3-A and AT1R-AA (HR = 3.23 [1.37-7.66], p = .008). All six double-positive patients lost their liver regrafts. In conclusion, LG3-A is associated with inferior long-term outcomes of a second liver transplant. Screening anti-HLA antibodies and autoantibodies such as LG3-A/AT1R-AA identifies patients with a higher risk for liver transplantation.

Rapid reduction of high-level pre-formed donor-specific antibodies after simultaneous liver-kidney transplantation: a report of two cases

Background

Kidney transplantation performed in the presence of high-titre donor-specific antibodies (DSA) may result in hyper-acute or accelerated antibody-mediated rejection and rapid allograft loss. Previous studies have shown that this risk may be mitigated with simultaneous liver-kidney transplantation (SLKT); however, the mechanisms are not well defined. Here we report the evolution of pre-formed, high-level DSAs in two highly sensitised SLKT recipients peri-operatively and describe a profound sustained depletion of all DSAs from the time of liver anastomosis with no extra desensitisation therapy required.

Case presentation

Two patients underwent SLKT and received our centre’s standard renal transplant immunosuppression with basiliximab and methylprednisolone for induction therapy and prednisolone, mycophenolate and tacrolimus for maintenance therapy. HLA antibody samples were collected pre-operatively, and immediately post-liver and post-kidney revascularisation, and then regularly in the post-transplant period. Complement Dependant Cytotoxicity (CDC) crossmatches were also performed. Both patients were highly sensitised with a PRA over 97%. One patient had a positive B- and T-cell crossmatch pre-transplant. These positive CDC crossmatches became negative and the level of pre-formed DSAs reduced profoundly and rapidly, within 3 h post-liver revascularisation. The reduction in pre-formed DSAs, regardless of subclass, was seen immediately post-liver revascularisation, before implantation of the renal allografts. No significant reduction in non-donor specific HLA-antibodies was observed. Both patients maintained good graft function with no rejection on kidney allograft protocol biopsies performed at 10-weeks post-transplant.

Conclusions

These cases support the protective immunoregulatory role of the liver in the setting of SLKT, with no extra desensitisation treatment given pre-operatively for these highly sensitised patients.

Preformed and de novo DSA are associated with T-cell-mediated rejection in pediatric liver transplant recipients requiring clinically indicated liver biopsy

Despite growing interest about the impact of donor-specific HLA antibodies (DSA) in LT limited data are available for pediatric recipients. Our aim was to perform a retrospective single-center chart review of children (0-16 years) having undergone LT between January 1, 2005 and December 31, 2017, to characterize DSA, to identify factors associated with the development of de novo DSA, and to analyze potential associations with the diagnosis of TCMR. Information on patient- and donor-characteristics and LB reports were analyzed retrospectively. Serum obtained before LT and at LB was analyzed for presence of recipient HLA antibody using Luminex^® technology. MFI > 1000 was considered positive. In 63 pediatric LT recipients with a median follow-up of 72 months, the overall prevalence of de novo DSA was 60.3%. Most were directed against class II antigens (33/38, 86.8%). Preformed DSA were present in 30% of patients. Twenty-eight (28/63) patients (44.4%) presented at least one episode of TCMR, mostly (12/28, 43%) moderate (Banff 6-7). De novo DSA were significantly more frequent in patients with TCMR than in patients without (75% vs 48.6%, P = .03), and patients with preformed and de novo DSA had a significantly higher rate of TCMR than patients without any DSA (66.7% vs 20%, P = .02). Neither preformed DSA nor de novo DSA were associated with frequency or severity of TCMR. Recipients with lower weight at LT developed de novo DSA more frequently (P = .04). De novo DSA were highly prevalent in pediatric LT recipients. Although associated with the development of TCMR, they did not appear to impact the frequency or severity of TCMR or graft survival. Instead, de novo DSA may suggest a state of insufficient IS.

Preformed donor-specific antibodies are associated with 90-day mortality in living-donor liver transplantation

AIM

The impact of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) on living donor liver transplantation (LDLT) is unclear. The aim of this study was to investigate the association between DSAs and short-term outcomes in LDLT recipients, and to clarify the clinical impact of DSAs.

METHOD

Anti-HLA antibodies were screened in preoperative serum samples taken from 40 liver transplant recipients at Ehime University (Toon, Japan) between August 2001 and July 2015. Screening was carried out using the Flow-PRA method, and DSAs were detected in anti-HLA antibody-positive recipients using the Luminex single-antigen identification test. A mean fluorescence intensity of 1000 was used as the cut-off for positivity. We retrospectively reviewed the clinical courses of patients who were DSA-positive to elucidate early clinical manifestations in LDLT recipients.

RESULTS

Fifteen (12 female and 3 male) patients (38%) had anti-HLA antibodies. Eight of the 15 anti-HLA antibody-positive patients were positive for DSAs, and all were women. The 90-day survival rate of DSA-positive patients (50%) was significantly lower than that of DSA-negative patients (84.4%) (0.0112; Wilcoxon test). On univariate analysis, the DSA-positive rate was significantly higher in the 90-day mortality group. Postoperatively, the incidence of acute cellular rejection was higher in DSA-positive than DSA-negative patients. Thrombotic microangiopathy developed only in DSA-positive patients. We found no relationship between DSA status and bile duct stricture.

CONCLUSION

Preformed DSAs could be associated with elevated 90-day mortality in LDLT recipients. Further large-scale studies are required to verify the risk associated with DSAs in LDLT.