Donor-directed MHC class I antibody is preferentially cleared from sensitized recipients of combined liver/kidney transplants

Summary of a Consensus Conference on the Management of Highly Sensitized Multiorgan Transplant Candidates

The number of highly sensitized patients in need of a multiorgan transplant is increasing. Criteria informing their transplant candidacy, approaches to management on the waitlist, and protocols related to alloantibody monitoring vary widely. We convened a consensus conference to discuss these different practices in the United States and the United Kingdom and to review the contemporary outcomes of these challenging cases. A detailed analysis of the data regarding the liver allografts' immunoprotective effect on simultaneously transplanted other organs was also completed, and the prospect of the use of liver allografts primarily to facilitate transplantation of highly sensitized patients in need of other organs was discussed. The ethical and allocation-related issues about such prospect were debated with a goal to standardize the approach and provide an evidence-based pathway for pre-, peri-, and post-transplantation management for the highly sensitized multiorgan transplantation candidate.

Simultaneous combined transplantation: Intricacies in immunosuppression management

Simultaneous combined transplantation (SCT), i.e. the transplantation of two solid organs within the same procedure, can be required when the patients develop more than one end-stage organ failure. The development of SCT over the last 20 years could only be possible thanks to progress in the surgical techniques and in the perioperative management of patients in an ageing population. Performing such major transplant surgeries from the same donor, in a short amount of time, and in critical pathophysiological conditions, is often considered to be counterbalanced by the immune benefits expected from these interventions. However, SCT includes a wide array of different transplant combinations, with each time a different immunological constellation. Recent research offers new insights into the immune mechanisms involved in these different settings. Progress in the understanding of these immunological intricacies help to address the optimal induction and maintenance immunosuppressive treatment strategies. In this review, we summarize the different immunological benefits according to the type of SCT performed. We also incorporate the main outcomes according to the immunological risk at transplantation, and the deleterious impact of preformed or de novo donor-specific antibodies (DSA) in the different types of SCT. Finally, we propose comprehensive and evidence-based induction and maintenance immunosuppression strategies guided by the type of SCT.

Combined Organ Transplantation in Patients with Advanced Liver Disease

Transplantation of the liver in combination with other organs is an increasingly performed procedure. Over the years, continuous improvement in survival could be realized through careful patient selection and refined organ preservation techniques, in spite of the challenges posed by aging recipients and donors, as well as the increased use of steatotic liver grafts. Herein, we revisit the epidemiology, allocation policies in different transplant zones, indications, and outcomes with regard to simultaneous organ transplants involving the liver, that is combined heart-liver, liver-lung, liver-kidney, and multivisceral transplantation. We address challenges surrounding combined organ transplantation such as equity, utility, and logistics of dual organ implantation, but also advantages that come along with combined transplantation, thereby focusing on molecular mechanisms underlying immunoprotection provided by the liver to the other allografts. In addition, the current standing and knowledge of machine perfusion in combined organ transplantation, mostly based on center experience, will be reviewed. Notwithstanding all the technical advances, shortage of organs, and the lack of universal eligibility criteria for certain multi-organ combinations are hurdles that need to be tackled in the future.

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.

Current approaches for risk assessment of intestinal transplant patients: A view from the histocompatibility laboratory

Despite its recent decline in volumes, intestinal transplantation remains an important option for patients with irreversible intestinal failures. The long-term outcome of an intestinal transplant has stagnated. The major cause of graft loss is rejection, resulting from mismatches in human leukocyte antigens (HLA) and the presence of antibodies to mismatched donor-specific HLA antigens (DSA). Literature has reported that DSAs, either preformed before transplantation or developed de novo after transplantation, are harmful to intestinal grafts, especially for those without combined liver grafts. A comprehensive assessment of DSA by the histocompatibility laboratory is critical for successful intestinal transplantation and its long-term survival. This paper briefly reviews the history and current status of different methods for detecting DSA and their clinical applications in intestinal transplantation. The focus is on applying different antibody assays to manage immunologically challenging intestinal transplant patients before and after transplantation. A clinical case is presented to illustrate the complexity of HLA tests and the necessity of multiple assays. The review of risk assessment by the histocompatibility laboratory also highlights the need for close interaction between the laboratory and the intestinal transplant program.

Targeting Liver Metastases to Potentiate Immunotherapy in MS-Stable Colorectal Cancer-A Review of the Literature

Immunotherapy has revolutionized the treatment of several cancers, including melanoma and lung cancer. However, for colorectal cancer, it is ineffective for 95% of patients with microsatellite-stable disease. Recent evidence suggests that the liver's immune microenvironment plays a pivotal role in limiting the effectiveness of immunotherapy. There is also evidence to show that targeting liver metastases with locoregional therapies, such as surgery or irradiation, could potentiate immunotherapy for these patients. This review presents evidence from preclinical studies regarding the underlying mechanisms and from clinical studies that support this approach. Furthermore, we outline potential directions for future clinical trials. This innovative strategy could potentially establish immunotherapy as an effective treatment for MS-stable colorectal cancer patients, which are currently considered resistant.

Detailed Analysis of Simultaneous Renal and Liver Allografts in the Presence of DSA

Liver allografts protect renal allografts from the same donor from some, but not all, preformed donor specific alloantibodies (DSA). However, the precise mechanisms of protection and the potential for more subtle alterations/injuries within the grafts resulting from DSA interactions require further study.

Methods

We reevaluated allograft biopsies from simultaneous liver-kidney transplant recipients who had both allografts biopsied within 60 d of one another and within 30 d of DSA being positive in serum (positive: mean florescence intensity ≥5000). Routine histology, C4d staining, and specialized immunohistochemistry for Kupffer cells (KCs; CD163) and a C4d receptor immunoglobulin-like transcript-4 were carried out in 4 patients with 6 paired biopsies.

Results

Overt antibody-mediated rejection was found in 3 of 4 renal and liver allografts. One patient had biopsy-confirmed renal and liver allograft antibody-mediated rejection despite serum clearance of DSA. All biopsies showed KC hypertrophy (minimal: 1; mild: 2; moderate: 1; severe: 2) and cytoplasmic C4d KC staining was easily detected in 2 biopsies from 2 patients; minimal and negative in 2 biopsies each. Implications of which are discussed. Control 1-y protocol liver allograft biopsies from DSA- recipients showed neither KC hypertrophy nor KC C4d staining (n = 6).

Conclusions

Partial renal allograft protection by a liver allograft from the same donor may be partially mediated by phagocytosis/elimination of antibody and complement split products by KCs, as shown decades ago in controlled sensitized experimental animal experiments.

Clinical Outcomes of Adult Fontan-Associated Liver Disease and Combined Heart-Liver Transplantation

BACKGROUND

The impact of Fontan-associated liver disease (FALD) on post-transplant mortality and indications for combined heart-liver transplant (CHLT) in adult Fontan patients remains unknown.

OBJECTIVES

The purpose of this study was to assess the impact of FALD on post-transplant outcomes and compare HT vs CHLT in adult Fontan patients.

METHODS

We performed a retrospective-cohort study of adult Fontan patients who underwent HT or CHLT across 15 centers. Inclusion criteria were as follows: 1) Fontan; 2) HT/CHLT referral; and 3) age ≥16 years at referral. Pretransplant FALD score was calculated using the following: 1) cirrhosis; 2) varices; 3) splenomegaly; or 4) ≥2 paracenteses.

RESULTS

A total of 131 patients (91 HT and 40 CHLT) were included. CHLT recipients were more likely to be older (P = 0.016), have a lower hemoglobin (P = 0.025), require ≥2 diuretic agents pretransplant (P = 0.051), or be transplanted in more recent decades (P = 0.001). Postmatching, CHLT demonstrated a trend toward improved survival at 1 year (93% vs 74%; P = 0.097) and improved survival at 5 years (86% vs 52%; P = 0.041) compared with HT alone. In patients with a FALD score ≥2, CHLT was associated with improved survival (1 year: 85% vs 62%; P = 0.044; 5 years: 77% vs 42%; P = 0.019). In a model with transplant decade and FALD score, CHLT was associated with improved survival (HR: 0.33; P = 0.044) and increasing FALD score was associated with worse survival (FALD score: 2 [HR: 14.6; P = 0.015], 3 [HR: 22.2; P = 0.007], and 4 [HR: 27.8; P = 0.011]).

CONCLUSIONS

Higher FALD scores were associated with post-transplant mortality. Although prospective confirmation of our findings is necessary, compared with HT alone, CHLT recipients were older with higher FALD scores, but had similar survival overall and superior survival in patients with a FALD score ≥2.

Examining the Role for Donor-specific Antibody Testing in Simultaneous Liver-kidney Transplantation: A Single-center Analysis of Outcomes

BACKGROUND

Simultaneous liver-kidney transplantation (SLKT) is increasingly used for patients with concurrent end-stage liver and renal disease. Emerging evidence suggests that simultaneous liver transplant can provide a tolerogenic benefit to multiorgan transplant recipients. Posttransplant donor-specific antibody (DSA) may be associated with worse outcomes; however, the role for testing DSA in SLKT is unclear.

METHODS

This study retrospectively assessed the impact of DSA on outcomes following primary SLKT at a large-volume center between 2008 and 2018. Patients were grouped by positive DSA, negative DSA, and DSA not tested, and data were obtained from our institutional database and chart review.

RESULTS

The cohort included 138 SLKT recipients with a mean age of 56.1 ± 9.7 y; 61.6% were male, and 55.8% were Hispanic. Overall, 62 patients were tested for DSA posttransplant, and 33 patients (23.9%) had at least 1 DSA detected. A total of 34 patients (24.6%) experienced at least 1 episode of liver rejection, and 23 patients (16.7%) experienced kidney rejection. Over 50% of patients with de novo DSA changed status during their posttransplant course. Rates of both liver and kidney rejection were slightly higher in the DSA + group, but liver allograft, kidney allograft, and patient survival did not differ when grouped by whether DSA testing was performed or DSA positivity.

CONCLUSIONS

These data demonstrate that SLKT is associated with excellent long-term patient and allograft survival with a relatively low rate of rejection. In our experience, testing for DSA does not impact SLKT outcomes' and further multicenter analyses are needed to establish standard of care.

Immunology of simultaneous liver and kidney transplants with identification and prevention of rejection

Simultaneous liver and kidney (SLK) transplantation is considered the best treatment modality among selected patients with both chronic kidney disease (CKD) and end-stage liver disease (ESLD). Since the first SLK transplant in 1983, the number of SLK transplants has increased worldwide, and particularly in the United States since the implementation of the MELD system in 2002. SLK transplants are considered a relatively low immunological risk procedure evidenced by multiple studies displaying the immunomodulatory properties of the liver on the immune system of SLK recipients. SLK recipients demonstrate lower rates of both cellular and antibody-mediated rejection on the kidney allograft when compared to kidney transplant-alone recipients. Therefore, SLK transplants in the setting of preformed donor-specific HLA antibodies (DSA) are a common practice, at many centers. Acceptance and transplantation of SLKs are based solely on ABO compatibility without much consideration of crossmatch results or DSA levels. However, some studies suggest an increased risk for rejection for SLK recipients transplanted across high levels of pre-formed HLA DSA. Despite this, there is no consensus regarding acceptable levels of pre-formed DSA, the role of pre-transplant desensitization, splenectomy, or immunosuppressive management in this unique population. Also, the impact of post-transplant DSA monitoring on long-term outcomes is not well-studied in SLK recipients. In this article, we review recent and relevant past articles in this field with a focus on the immunological risk factors among SLK recipients, and strategies to mitigate the negative outcomes among them.

Long-term outcomes of crossmatch positive simultaneous liver-kidney transplantations in the United States

The long-term outcomes of positive crossmatch (+XM) simultaneous liver-kidney (SLK) transplantations are conflicting. We examined the association between crossmatch status and SLK outcomes in recipients discharged on tacrolimus and mycophenolate with or without steroids. We analyzed the Scientific Registry of Transplant Recipients for all primary SLK recipients between 2003 and 2020 with available crossmatch and induction data. We grouped recipients according to the crossmatch status: negative crossmatch (-XM; n = 3040) and +XM (n = 407). Kaplan-Meier curves were generated to examine recipient, death-censored liver, and death-censored kidney survival by crossmatch status. Cox proportional hazard models were used to investigate the association between crossmatch status and outcomes of interest with follow-up censored at 10 years. Models were adjusted for recipient age, sex, diabetes mellitus, Model for End-Stage Liver Disease score, duration on the liver waiting list, induction immunosuppression, steroid maintenance, hepatitis C infection, donor age and sex, local vs. shared organ, cold ischemia time, and previous liver transplantation status. In the univariable analysis, crossmatch status was not associated with recipient survival (log-rank p = 0.63), death-censored liver graft survival (log-rank p = 0.05), or death-censored kidney graft survival (log-rank p = 0.11). Compared with -XM, +XM recipients had a similar 1-year liver rejection rate, but higher kidney rejection rate (4.6% vs. 8.9%, p = 0.002). In the multivariable models, +XM status was not associated with deleterious long-term recipient, liver, or kidney grafts survival. -XM and +XM SLK transplantations have comparable long-term recipient, liver graft, and kidney survival with a slightly increased risk of early kidney allograft rejection in the +XM group. Crossmatch positivity in SLK transplantations should not influence the decision to use organs from a specific donor.

Incidence of acute rejection and patient survival in combined heart-liver transplantation

Combined heart-liver transplantation (CHLT) is indicated for patients with concomitant end-stage heart and liver disease or patients with amyloid heart disease where liver transplantation mitigates progression. Limited data suggest that the liver allograft provides immunoprotection for heart and kidney allografts in combined transplantation from the same donor. We hypothesized that CHLT reduces the incidence of acute cellular rejection (ACR) and the development of de novo donor-specific antibodies (DSAs) compared with heart-alone transplantation (HA). We conducted a retrospective analysis of 32 CHLT and 280 HA recipients in a single-center experience. The primary outcome was incidence of ACR based on protocol and for-cause myocardial biopsy. Rejection was graded by the International Society of Heart and Lung Transplantation guidelines with Grade 2R and higher considered significant. Secondary outcomes included the development of new DSAs, cardiac function, and patient and cardiac graft survival rates. Of CHLT patients, 9.7% had ACR compared with 45.3% of HA patients (p < 0.01). Mean pretransplant calculated panel reactive antibody (cPRA) levels were similar between groups (CHLT 9.4% vs. HA 9.5%; p = 0.97). Among patients who underwent testing, 26.9% of the CHLT and 16.7% of HA developed DSA (p = 0.19). Despite the difference in ACR, patient and cardiac graft survival rates were similar at 5 years (CHLT 82.1% vs. HA 80.9% [p = 0.73]; CHLT 82.1% vs. HA 80.9% [p = 0.73]). CHLT reduced the incidence of ACR in the cardiac allograft, suggesting that the liver offers immunoprotection against cellular mechanisms of rejection without significant impacts on patient and cardiac graft survival rates. CHLT did not reduce the incidence of de novo DSA, possibly portending similar long-term survival among cardiac allografts in CHLT and HA.

Crossmatch, Donor-specific Antibody Testing, and Immunosuppression in Simultaneous Liver and Kidney Transplantation: A Review

Since the introduction of simultaneous liver-kidney transplantation (SLKT) in the 1960s, the potential for immunological protection from the liver allograft to a simultaneously transplanted kidney has been recognized. Due to expanded indications and changes in allocation policies, there has been increased utilization of SLKT. Despite growing experience, a lack of consensus exists regarding the extent of the immunological privilege of the liver the role for donor-specific HLA antibody (DSA) and crossmatch testing, and appropriateness of modern immunosuppression protocols in SLKT recipients. This review provides a detailed analysis of SLKT outcomes in the context of these factors, suggesting that although the liver can reduce the incidence of antibody-mediated rejection, attention should be given to liver allograft function, previous failed transplants, and other risk factors in pretransplant risk assessment. Current methods of DSA and crossmatch testing in SLKT are also discussed, and the role of specific DSA (high mean fluorescence intensity antibody, C1q+ binding) and their potential importance in posttransplant risk assessment are examined. Finally, trends in SLKT immunosuppression are discussed, including the use of nondepleting agents for induction and de-escalating use of steroids for maintenance immunosuppression. Ongoing research, including multicenter or randomized trials, will be necessary to optimize immune-related outcomes in SLKT recipients.

The Utility of Donor-specific Antibody Monitoring and the Role of Kidney Biopsy in Simultaneous Liver and Kidney Recipients With De Novo Donor-specific Antibodies

BACKGROUND

There is limited information about the utility of donor-specific antibody (DSA) against HLA monitoring and the role of protocol kidney biopsy for de novo DSA (dnDSA) in simultaneous liver and kidney (SLK) transplant recipients.

METHODS

We analyzed SLK transplant recipients transplanted between January 2005 and December 2017, who had DSA checked posttransplant. Patients were divided into 2 groups based on whether they developed dnDSA posttransplant (dnDSA+) or not (dnDSA-). Kidney graft rejection ±45 d of dnDSA and a kidney death-censored graft survival were the primary endpoints.

RESULTS

A total of 83 SLK transplant recipients fulfilled our selection criteria. Of those, 23 were dnDSA+ and 60 were dnDSA-. Twenty-two of 23 dnDSA+ patients had DSA against class II HLA, predominantly against DQ. Fifteen recipients underwent kidney biopsy ±45 d of dnDSA. Six of these were clinically indicated due to kidney graft dysfunction. The other 9 had a protocol kidney biopsy only due to dnDSA, and 6 of these 9 had a rejection. Also, 3 recipients had sequential biopsies of both the kidney and liver grafts. Among those with sequential biopsies of both grafts, there was a difference between the organs in the rate and types of rejections. At last follow up, dnDSA was not associated with graft failure of either the kidney or liver.

CONCLUSIONS

Although our study was limited by a small sample size, it suggests the potential utility of DSA monitoring and protocol kidney biopsy for dnDSA.

Combined liver-kidney transplantation with positive crossmatch: Role of delayed kidney transplantation

BACKGROUND

Positive crossmatch (XM+) combined liver-kidney transplantation due to preformed donor-specific human leukocyte antigen antibodies has produced mixed results. We sought to understand the role of delayed kidney transplant approach in XM+ combined liver-kidney transplantations.

METHODS

XM+ combined liver-kidney transplantations were retrospectively reviewed. T- and B-cell XM, complement-dependent cytotoxic crossmatch, and flow cytometric crossmatch were performed prospectively.

RESULTS

Of 183 combined liver-kidney transplantations performed (2002-2019), 114 (62%) were with "delayed" kidney transplant approach and 19 (19 of 183, 10%) were XM+. Of 19 XM+ combined liver-kidney transplantations, kidney transplant was "delayed" in 14 by an average of 47 hours (range 24-64 hours) from liver transplant. There was a significant reduction in both class I (mean pre-liver transplant mean fluorescence intensity (MFI) 26,230 versus mean post-liver transplant and pre-delayed kidney transplant MFI 3,272, P = .01) and total MFI (mean pre-liver transplant MFI 27,233 vs mean post liver transplant and predelayed kidney transplant MFI 11,469, P = .01). However, there was no significant change in the MFI of class II donor-specific antibodies (mean pre-liver transplant MFI 17,899 versus post-liver transplant and pre-delayed kidney transplant MFI 14,341, P = .19). None of XM+ delayed kidney transplants had delayed graft function, and there was no antibody-mediated rejection. One-year patient survival for the XM+ combined liver-kidney transplantation with delayed kidney transplant approach was 92.9%, which is comparable to patient survival of XM- combined liver-kidney transplantation. Whereas patient survival in recipients before "delayed" approach ("simultaneous"; n = 5) was 40% when liver-kidney transplants were performed simultaneously (P = .06).

CONCLUSION

In sensitized combined liver-kidney transplantation recipients, the "delayed" kidney transplant approach is associated with a significant reduction in total and class I donor-specific antibodies after liver transplant before kidney transplant, enabling therapeutic interventions such as plasmapheresis, if needed, providing optimal outcomes similar to crossmatch recipients.

Heart-After-Liver Transplantation Attenuates Rejection of Cardiac Allografts in Sensitized Patients

BACKGROUND

In patients undergoing heart transplantation, significant allosensitization limits access to organs, resulting in longer wait times and high waitlist mortality. Current desensitization strategies are limited in enabling successful transplantation.

OBJECTIVES

The purpose of this study was to describe the cumulative experience of combined heart-liver transplantation using a novel heart-after-liver transplant (HALT) protocol resulting in profound immunologic protection.

METHODS

Reported are the results of a clinical protocol that was instituted to transplant highly sensitized patients requiring combined heart and liver transplantation at a single institution. Patients were dual-organ listed with perceived elevated risk of rejection or markedly prolonged waitlist time due to high levels of allo-antibodies. Detailed immunological data and long-term patient and graft outcomes were obtained.

RESULTS

A total of 7 patients (age 43 ± 7 years, 86% women) with high allosensitization (median calculated panel reactive antibody = 77%) underwent HALT. All had significant, unacceptable donor specific antibodies (DSA) (>4,000 mean fluorescence antibody). Prospective pre-operative flow cytometric T-cell crossmatch was positive in all, and B-cell crossmatch was positive in 5 of 7. After HALT, retrospective crossmatch (B- and T-cell) became negative in all. DSA fell dramatically; at last follow-up, all pre-formed or de novo DSA levels were insignificant at <2,000 mean fluorescence antibody. No patients experienced >1R rejection over a median follow-up of 48 months (interquartile range: 25 to 68 months). There was 1 death due to metastatic cancer and no significant graft dysfunction.

CONCLUSIONS

A heart-after-liver transplantation protocol enables successful transplantation via near-elimination of DSA and is effective in preventing adverse immunological outcomes in highly sensitized patients listed for combined heart-liver transplantation.

Optimizing the Selection of Patients for Simultaneous Liver-Kidney Transplant

Simultaneous liver-kidney transplantation has increased significantly in the Model for End Stage Liver Disease era. The transplantation policy has evolved significantly since the implementation of allocation based on the Model for End Stage Liver Disease. Current policy takes into account the medical eligibility criteria for simultaneous liver-kidney transplantation listing. It also provides a safety net option and prioritizes kidney transplant after liver transplant recipients who are unlikely to recover their renal function within 60 to 365 days after liver transplant alone. This review seeks to understand the underlying challenges in carefully selecting the candidates while optimizing the patient selection.

Donor-specific antibody and sensitized patients in intestinal transplantation

PURPOSE OF REVIEW

It has been well established that antibody to donor HLA pretransplant and the development of anti-human leukocyte antigen (HLA) antibodies posttransplant contribute to inferior graft survival outcomes. This article serves to review the current status of the management of pretransplant sensitized intestinal transplant candidate as well as to review posttransplant care of patients that harbor antidonor HLA antibodies.

RECENT FINDINGS

The intestinal transplant candidate oftentimes presents for transplant listing with high levels of anti-HLA antibodies that necessitate a careful preoperative strategy to avoid a donor-recipient pair that would result in a positive crossmatch. In the end, donor intestine offer acceptance is based on a balance between recipient clinical needs and allowable immunologic risk tolerance. The use of virtual crossmatching (VXM) enables the transplant center to effectively gauge the immunologic risk of each potential donor-recipient pair far in advance of allocating resources toward pursuing a donor organ. In those candidates with high levels of preformed donor anti-HLA antibodies, desensitization with a novel technique of donor splenic perfusion has been described as well as a single-center experience with a conventional desensitizing protocol. Posttransplant, with the use of a denovo donor-specific antibody (dnDSA) monitoring and treatment protocol, the well known deleterious effects of dnDSA can potentially be ameliorated, thus improving outcome. Efforts to establish a formal histologic criteria for antibody-mediated rejection (ABMR) in the intestinal graft continues to evolve with recent findings describing the relationship between DSA and histopathologic findings.

SUMMARY

Techniques such as the use of VXM, novel desensitization methods and protocols, monitoring and eradicating dnDSA, along with establishing new criteria for ABMR have all contributed to improving the outcomes in transplanting the immunologically challenging intestine.

Intra-operative kinetics of anti-HLA antibody in simultaneous liver-kidney transplantation

During simultaneous liver-kidney transplantation (SLK) in highly sensitized patients, donor specific anti-human leukocyte antigen antibodies (DSA, HLA) can be present prior to transplant leading to positive crossmatch, yet these recipients have relatively low incidences of acute rejection. The mechanisms and timing underlying immunologic changes that occur intra-operatively remain largely unknown. Therefore, we measured the intra- and peri-operative kinetics of anti-HLA antibodies in highly sensitized SLK recipients. In this study, pre- and post-operative blood samples were obtained from sensitized SLK candidates with documented DSA. Intra-operative samples were obtained from a sub-group of SLK recipients. Pretransplant anti-HLA antibody profiles were created and flow cytometry and anti-human globulin complement-dependent cytotoxic crossmatches were performed. Significant reductions in anti-HLA class I and II DSA were seen intra-operatively shortly after reperfusion of the liver allograft. This effect was most pronounced for anti-HLA class I DSA (mean change, −85%, p < 0.05); changes to anti-HLA class II DSA were less robust (mean change, −47%, p = 0.15). Importantly, non-DSA anti-HLA antibodies remained unchanged throughout the perioperative period, suggesting the mechanism(s) by which the liver lowers DSA levels are specific to the DSA. These data demonstrate the immunologic benefit of performing SLK is lasting and occurs very shortly after liver reperfusion.

Association between longer hospitalization and development of de novo donor specific antibodies in simultaneous liver-kidney transplant recipients

Background: De novo Donor Specific Antibodies (DSA) are considered as a risk factor for the kidney allograft outcomes in recipients after simultaneous liver-kidney transplantation (SLKT). We hypothesized that length of hospital stay (LOS) might be associated with de novo DSA development of due to the increased likelihood of receiving blood transfusions with reduced immunosuppressive regimens.Methods: This study is a single-center, retrospective cohort study consisting of 85 recipients who underwent SLKT from 2009 to 2018 in our hospital. We divided the patients into two groups according to LOS [long hospital stay (L) group (LOS >14 days) and short hospital stay (S) group (LOS ≤14 days)]. Propensity score (PS) has been created using logistic regression to predict LOS greater than median of 14 days. The association between the presence of de novo DSA and LOS was assessed by logistic regression models adjusted for PS.Results: The mean age at transplantation of the entire cohort was 55.5 ± 10.1 years. Sixty percent of the recipients were male and Caucasian. Median LOS in (L) group was three-fold longer than (S) group [L: median 30 days (IQR: 21-52), S: median 8.5 days (IQR: 7-11)]. Eight patients developed de novo DSA after SLKT (9.4%), all of them were in (L) group. Longer LOS was significantly associated with higher risk of development of de novo DSA in unadjusted (OR+ each 5 days: 1.09, 95% CI:1.02-1.16) and PS adjusted (OR+ each 5 days: 1.11, 95% CI:1.02-1.21) analysis.Conclusion: Longer hospitalization is significantly associated with the development of de novo DSA in SLKT.

Donor-specific antibodies in liver transplantation: challenges in diagnosis and determining clinical impact

PURPOSE OF REVIEW

Our understanding of the clinical impact of donor-specific antibodies in liver transplant recipients has evolved in recent years as outcomes for liver allografts have improved and advances in diagnostic testing have made recognition of antibody mediated rejection in transplant patients more sensitive.

RECENT FINDINGS

Two main types of donor-specific antibodies - preformed and de novo - have been reported in the literature to have a negative impact on graft survival, and researchers have been able to further identify subclasses of class II donor-specific antibodies as being the most clinically impactful. Furthermore, there is evidence that donor-specific antibody formation can augment cellular rejection in liver grafts and lead to worsened clinical outcomes. Recent data have shown a higher prevalence of donor-specific antibody formation than previously reported.

SUMMARY

This review explores the most recent literature regarding the clinical impact of both preformed and de-novo donor-specific antibodies and potential management guidelines for patients undergoing liver transplantation. The best practice guidelines for undergoing monitoring for donor-specific antibody formation and protocol biopsies in sensitized patients will depend on further multiinstitutional studies.

Impact of Induction Immunosuppression Strategies in Simultaneous Liver/Kidney Transplantation

BACKGROUND

There is scant data on the use of induction immunosuppression for simultaneous liver/kidney transplantation (SLKT).

METHODS

We analyzed the Organ Procurement and Transplant Network registry from 1996 to 2016 to compare outcomes of SLKT, based on induction immunosuppression.

RESULTS

Of 5172 patients, 941 (18%) received T-cell depletion induction, 1635 (32%) received interleukin 2 receptor antagonist (IL2-RA), and 2596 (50%) received no induction (NI). At 5 years, patient survivals were 68% in the T-cell group, 74% in the IL2-RA group, and 71% in the NI group (P = 0.0006). Five-year liver and kidney allograft survivals were 67% and 64% in the T-cell group, 73% and 70% in the IL2-RA group, and 70% and 68% in the NI group (P = 0.001 and 0.003), respectively. On multivariate analysis, the type of induction had no impact on patient or allograft survival. Maintenance steroids and calcineurin inhibitors (CNIs) at discharge were associated with improved patient and graft survival (steroids: patient survival hazard ratio [HR] 0.37 [0.27-0.52], liver survival HR 0.43 [0.31-0.59], kidney survival HR 0.46 [0.34-0.63]; P < 0.0001, CNI: patient survival HR 0.3 [0.21-0.43], liver survival HR 0.3 [0.2-0.44], kidney survival HR 0.4 [0.26-0.59]; P < 0.0001). CNI maintenance in patients who received T-cell induction was associated with decreased patient, liver, and kidney allograft survivals (respective HR: 1.4 [1.1, 1.8]; 1.5 [1.1, 1.9]; 1.3 [1.08, 1.7]; P < 0.05) CONCLUSION.: Induction immunosuppression had no impact on patient and allograft survival in SLKT, while maintenance steroids and CNI were associated with improved patient and graft survivals. Given the inherent limitations of a registry analysis, these findings should be interpreted with caution.

HLA class II donor specific antibodies are associated with graft cirrhosis after liver transplant independent of the mean fluorescence intensity level

Background

The importance of donor-specific antibodies (DSA) after liver transplantation (LT) for graft and patient survival is an ongoing controversy. So far it has not been elucidated when and in how far DSA are harmful for graft and patient survival. Therefore, we had the aim to investigate the association of DSA with complications after LT.

Methods

Data of 430 LT recipients were collected and statistically analyzed. Detection of HLA antibodies (Ab) was performed by Luminex assay.

Results

DSA were detected in 81 patients (18.8%). These were mainly HLA class II Ab (81.5%). HLA class II Ab show a higher MFI (median: 5.300) compared to HLA class I Ab (median: 2.300). There is no association between MFI levels and development of complications after LT. However, cirrhosis occurred significantly more often in DSA positive patients (18%) than in patients without detectable DSA (9%, P = 0.027). All DSA positive patients with cirrhosis of the graft showed HLA class II antibodies (OR: 3.028; 95% CI: 1.51–6.075; P = 0.002).

Conclusion

Occurrence of HLA class II DSA after LT is associated with graft cirrhosis and may indicate a higher risk to develop graft damage independent on MFI and requires an individualized risk management.

Delayed Implantation of Pumped Kidneys Decreases Renal Allograft Futility in Combined Liver-Kidney Transplantation

BACKGROUND

Combined liver-kidney transplantation (CLKT) improves survival for liver transplant recipients with renal dysfunction; however, the tenuous perioperative hemodynamic and metabolic milieu in high-acuity CLKT recipients increases delayed graft function and kidney allograft failure. We sought to analyze whether delayed KT through pumping would improve kidney outcomes following CLKT.

METHODS

A retrospective analysis (University of California Los Angeles [n = 145], Houston Methodist Hospital [n = 79]) was performed in all adults receiving CLKT at 2 high-volume transplant centers from February 2004 to January 2017, and recipients were analyzed for patient and allograft survival as well as renal outcomes following CLKT.

RESULTS

A total of 63 patients (28.1%) underwent delayed implantation of pumped kidneys during CLKT (dCLKT) and 161 patients (71.9%) received early implantation of nonpumped kidneys during CLKT (eCLKT). Most recipients were high-acuity with median biologic model of end-stage liver disease (MELD) score of, 35 for dCLKT and 34 for eCLKT (P = ns). Pretransplant, dCLKT had longer intensive care unit stay, were more often intubated, and had greater vasopressor use. Despite this, dCLKT exhibited improved 1-, 3-, and 5-year patient and kidney survival (P = 0.02) and decreased length of stay (P = 0.001), kidney allograft failure (P = 0.012), and dialysis duration (P = 0.031). This reduced kidney allograft futility (death or continued need for hemodialysis within 3 mo posttransplant) for dCLKT (6.3%) compared with eCLKT (19.9%) (P = 0.013).

CONCLUSIONS

Delayed implantation of pumped kidneys is associated with improved patient and renal allograft survival and decreased hospital length of stay despite longer kidney cold ischemia. These data should inform the ethical debate as to the futility of performing CLKT in high-acuity recipients.

Kidney Rejection Following Simultaneous Liver-kidney Transplantation

BACKGROUND

Donor-specific antibodies are reported to increase the risk of rejection and reduce allograft survival following simultaneous liver-kidney transplantation. Optimal immunosuppression regimens to reduce this risk and to treat rejection episodes are underinvestigated.

METHODS

Cohort analysis of the first 27 simultaneous liver-kidney transplant recipients, between 2014 and 2018 at our unit, is performed under a new risk stratification policy. Those with donor-specific antibodies to class II HLA with a mean fluorescence intensity >10 000 are considered high risk for antibody-mediated rejection (AMR). These patients received immunosuppression, which consisted of induction therapy, tacrolimus, mycophenolate mofetil, and prednisolone. All other patients are considered low risk and received tacrolimus and prednisolone alone.

RESULTS

Three patients were high risk for rejection, and 2 of these patients developed AMR, which was treated with plasma exchange and intravenous immunoglobulin. At 1 y, their estimated glomerular filtration rate (eGFR) were 50 and 59 mL/min. Two other patients developed AMR, which was similarly treated, and their 1-y eGFR was 31 and 50 mL/min. The overall histologically proven acute rejection rate within the first year was 33%, and median eGFR, for the 27 patients, at 1 y was 52 mL/min and at 2 y was 49 mL/min.

CONCLUSIONS

This study confirms that there is a risk of AMR following simultaneous liver-kidney transplantation despite increased immunosuppression. This can be effectively treated with plasma exchange and intravenous immunoglobulin.

A 14-Year Follow-Up of a Combined Liver-Pancreas-Kidney Transplantation: Case Report and Literature Review

Objective: To investigate the long-term effect of triple organ transplantation (liver, kidney, and pancreas) in a patient with end-stage liver disease, post chronic hepatitis B, cirrhosis, chronic renal failure, and insulin-dependent diabetes mellitus caused by chronic pancreatitis and to explore the optimal surgical procedure.

Case: A 43-year-old man with progressive emaciation and hypourocrinia for 2 months. Results indicated exocrine pancreatic insufficiency and insulin-dependent diabetes related to chronic pancreatitis (CP) after developing end-stage hepatic and renal failure. Simultaneous piggyback orthotopic liver and heterotopic pancreas-duodenum and renal transplantation was performed in 2005. Pancreatic exocrine secretions were drained enterically to the jejunum, and the donor kidney was placed in the left iliac fossa. Patient was prescribed with prednisone, tacrolimus, mycophenolate mofetil, Rabbit Anti-human Thymocyte Immunoglobulin, and simulect for immunosuppression.

Results: Satisfactory hepatic and pancreatic functional recovery was achieved within 7 days post-surgery. The kidney was not functional, and continuous renal replacement therapy was used. However, the donor kidney was removed at day 16 post-surgery due to acute rejection reaction. A new renal transplantation at the same position was performed, and satisfactory kidney function from the new graft was achieved 3 days later. In 14 years of follow-up, patient has not had any rejection reactions or other complications such as pancreatitis, thrombosis, and localized infections. The patient is insulin independent with normal liver and renal functions. FK506+Pred was used for immunosuppression, and the tac tough level maintained 3.0–4.5 ng/ml. Lamivudine was prescribed for long-term use to inhibit HBV virus duplication.

Conclusion: Simultaneous piggyback orthotopic liver and heterotopic pancreas-duodenum and renal transplantation is a good therapeutic option for patients with exocrine pancreatic insufficiency and insulin-dependent diabetes combined with hepatic and renal failure.

Kidney Graft Outcomes in High Immunological Risk Simultaneous Liver-Kidney Transplants

Recipients of simultaneous liver-kidney transplantations (SLKTs) have a lower risk of rejection compared with recipients of kidney transplants alone. However, there is disagreement about the impact of pretransplant anti-human leukocyte antigen sensitization on patient and kidney graft survival in the long term. The aim of the study was to evaluate the impact of the recipient immunological risk and comorbidities in renal graft outcomes on SLKT. We reviewed the SLKTs performed in our center from May 1993 until September 2017. Patient and graft survival were analyzed according to the immunological risk, comorbidities, liver and kidney rejection episodes, immunosuppression, and infections. A total of 20 recipients of SLKT were considered in the high immunological risk (HIR) group, and 68 recipients were included in the low immunological risk (LIR) control group. The prevalence of hepatitis C virus infection, second renal transplant, and time on dialysis prior to transplantation were significantly higher in the HIR group. The incidence of acute kidney rejection was higher in the HIR group (P<0.01). However, death-censored kidney graft survival as well as the estimated glomerular filtration rate at follow-up were not different between the 2 groups. Comorbidities, but not the immunological risk, impact negatively on patient survival. Despite the higher incidence of rejection in the HIR SLKT group, longterm renal function and graft survival were similar to the LIR group.

Living donor liver transplantation for congenital hepatic fibrosis in children

Congenital hepatic fibrosis (CHF) often accompanies autosomal recessive polycystic kidney disease (ARPKD), which stems from a PKHD1 gene mutation. The aim of this study was to clarify the prognosis of children with CHF who received living donor liver transplantation (LDLT) from donors who might be heterozygous carriers of a hepatorenal fibrocystic disease. Fourteen children with CHF who underwent LDLT at our center were enrolled. Eight and two patients had ARPKD and nephronophthisis, respectively. Eight of the donors were the recipients' fathers, and six donors were their mothers. We examined the histological and radiological findings of the donor livers and complications in the recipients following the liver transplantation. Seven of the donor livers presented morphological abnormalities of the bile ducts. Abdominal computed tomography revealed liver cysts in eight donors. One recipient underwent re-LT for graft failure due to rejection. Three patients presented with rejection, and one presented with sepsis. The overall survival rate was 100% and the original graft survival rate was 93%. In conclusion, the prognosis of recipients who received a LDLT from their parents for CHF was excellent. However, the morphology of half the donor livers was abnormal. Careful follow-up is needed to ensure long-term graft survival.

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.

Association between post-transplant donor-specific antibodies and recipient outcomes in simultaneous liver-kidney transplant recipients: single-center, cohort study

There is a dearth of published data regarding the presence of post-transplant donor-specific antibodies (DSA), especially C1q-binding DSA (C1q+DSA), and patient and kidney allograft outcomes in simultaneous liver-kidney transplant (SLKT) recipients. We conducted a retrospective cohort study consisted of 85 consecutive SLKT patients between 2009 and 2018 in our center. Associations between presence of post-transplant DSA, including persistent and/or newly developed DSA and C1q+DSA, and all-cause mortality and the composite outcome of mortality, allograft kidney loss, and antibody-mediated rejection were examined using unadjusted and age and sex-adjusted Cox proportional hazards and time-dependent regression models. The mean age at SLKT was 56 years and 60% of the patients were male. Twelve patients (14%) had post-transplant DSA and seven patients (8%) had C1q+DSA. The presence of post-transplant DSA was significantly associated with increased risk of mortality (unadjusted model: Hazard Ratio (HR) = 2.72, 95% confidence interval (CI): 1.06-6.98 and adjusted model: HR = 3.20, 95% CI: 1.11-9.22) and the composite outcome (unadjusted model: HR = 3.18, 95% CI: 1.31-7.68 and adjusted model: HR = 3.93, 95% CI: 1.39-11.10). There was also higher risk for outcomes in recipients with C1q+DSA compared the ones without C1q+DSA. Post-transplant DSA is significantly associated with worse patient and kidney allograft outcomes in SLKT. Further prospective and large cohort studies are warranted to better assess these associations.

Lack of Association between Pretransplant Donor-Specific Antibodies and Posttransplant Kidney Outcomes in Simultaneous Liver-Kidney Transplant Recipients with Rabbit Anti-Thymocyte Globulin Induction and Steroid-Free Protocol

INTRODUCTION AND OBJECTIVE

The impact of pretransplant donor-specific antibodies (DSAs), especially class II DSAs, on kidney allograft outcomes remains unclear in simultaneous liver-kidney transplantation (SLKT) recipients.

METHODS

We examined 85 recipients who consecutively underwent SLKT between 2009 and 2018 in our center. Associations between pretransplant DSA and worsening kidney function (WKF), kidney allograft loss, composite kidney outcome (WKF and/or antibody-mediated rejection and/or death-censored kidney allograft loss), death with functioning graft, and overall mortality were examined in survival analysis. WKF was defined as an eGFR decrease of 30% or greater from baseline, or 2 or more episodes of proteinuria, at least 90 days apart from each other.

RESULTS

The mean age at SLKT was 56 ± 10 years, and 62% of the recipients were male. More than one quarter (26%) of our recipients were African American. The 2 major causes of end-stage liver disease were hepatitis C (28%) and alcoholic hepatitis (26%). Nineteen recipients (22%) had pretransplant DSAs at the time of SLKT. The DSA(+) group and DSA(-) group had similar risk of WKF (unadjusted model: hazard ratio [HR] = 0.77, 95% confidence interval [CI]: 0.29-2.05 and adjusted model: HR = 0.36, 95% CI: 0.12-1.08); similar risk of composite kidney outcome (unadjusted model: HR = 1.04, 95% CI: 0.45-2.43 and adjusted model: HR = 0.53, 95% CI: 0.20-1.39); and similar risk of overall death (unadjusted model: HR = 1.23, 95% CI: 0.45-3.36 and adjusted model: HR = 1.28, 95% CI: 0.42-3.87). We found similar results when comparing different DSA subclasses (class I and II DSAs) with recipients without DSAs.

CONCLUSIONS

The presence of pretransplant DSAs was not associated with worse kidney allograft outcomes from our single-center experience. Further prospective larger studies are strongly warranted.

Heart-Kidney and Heart-Liver Transplantation Provide Immunoprotection to the Cardiac Allograft

BACKGROUND

Prior single-center studies suggest that kidney and liver allografts are immunoprotective toward transplanted hearts. The broader effects of the simultaneous transplantation of kidney or liver on protection from rejection are unclear.

METHODS

The United Network for Organ Sharing database for heart transplantation was queried from 1987 to 2015 and stratified into patients undergoing heart-liver transplantation (HLT) (n = 192), heart-kidney transplantation (HKT) (n = 1,174), and heart-only transplantation (HT) (n = 61,471). Perioperative and follow-up data were compared between HT versus HLT and HT versus HKT groups using analysis of variance (continuous), chi-square test (categorical), and Kaplan-Meier curves (survival).

RESULTS

HKT patients were older (51.2 ± 13.4 years of age) compared with HT patients (45.6 ± 19.2 years of age; p < 0.0001), with higher rate of diabetes (33.8% versus 14.8%; p < 0.0001) and dialysis (49.7% versus 2.1%; p < 0.0001). HKT (46.2%) and HLT (49.5%) patients had more urgent need for transplantation (status 1A) compared with HT patients (32%; p < 0.0001). Acute rejection episodes before discharge were lower in the HLT group (7.1% versus 3.1%; p = 0.03). Ten-year patient survivals were similar for HT (53.6%) versus HKT (56.7%) (p = 0.13) versus HLT (60.4%) (p = 0.09). Treatment for rejection during the first posttransplant year was lower in HLT (2.1%) and HKT (8.4%) compared with HT (17.4%) (p < 0.0001 for both). Cox multivariate analysis showed that cardiac allograft survival was improved in HKT (odds ratio, 0.58; 95% confidence interval [CI], 0.49 to 0.70; p < 0.0001). Additionally, HKT (hazard ratio, 0.52; 95% CI, 0.45 to 0.60; p < 0.0001) and HLT (hazard ratio, 0.24; 95% CI, 0.15 to 0.39; p < 0.0001) were associated with improved freedom from rejection.

CONCLUSIONS

Nationally, HKT and HLT have equivalent postoperative outcomes as HT. Simultaneous kidney or liver transplantation confers an improved clinical and immunologic outcome.

International Liver Transplantation Society Consensus Statement on Immunosuppression in Liver Transplant Recipients

Effective immunosupression management is central to achieving optimal outcomes in liver transplant recipients. Current immunosuppression regimens and agents are highly effective in minimizing graft loss due to acute and chronic rejection but can also produce a substantial array of toxicities. The utilization of immunosuppression varies widely, contributing to the wide disparities in posttransplant outcomes reported between transplant centers. The International Liver Transplantation Society (ILTS) convened a consensus conference, comprised of a global panel of expert hepatologists, transplant surgeons, nephrologists, and pharmacologists to review the literature and experience pertaining to immunosuppression management to develop guidelines on key aspects of immunosuppression. The consensus findings and recommendations of the ILTS Consensus guidelines on immunosuppression in liver transplant recipients are presented in this article.

Impact of persistent and cleared preformed HLA DSA on kidney transplant outcomes

Preformed HLA donor-specific antibodies (DSA) only detected with Luminex have been associated with increased risk of antibody-mediated rejection (ABMR) and graft failure after kidney transplantation (KT). Their evolution after KT may modify this risk. We analyzed postransplant evolution of preformed DSA identified retrospectively and their impact on outcomes of 370 KT performed 2006-2014. Antibodies were monitored prospectively at 1-3-5 years after KT and if any dysfunction. Early acute ABMR was more frequent among patients with preformed DSA class-I or I + II than isolated class-II (29.4% vs 4.5%, p = 0.02). One year post-KT, 20 of 34 patients with functioning KT had persistent DSA. Preformed DSA class-II persisted more frequently than class-I/I + II (66.7% vs 33.3%; p = 0.031). The only risk factor independently associated with persistence was pretransplant MFI. Patients with de novo DSA had the highest risk of ABMR (HR 22.2 [CI 6.1-81.2]). Although recipients with persisting preformed DSA had significantly increased ABMR risk (HR 14.7 [CI 6.5-33.0]), those with cleared preformed DSA also had a higher risk than those without DSA (HR 7.01 [CI 2.2-21.8]). Preformed DSA are a very important risk factor for ABMR and graft loss. Patients who clear preformed DSA still show an increased risk of ABMR and graft loss after KT.

Application and interpretation of histocompatibility data in liver transplantation

PURPOSE OF REVIEW

There has been a resurgence of interest in histocompatibility as it applies to liver transplantation. The association of persistent and de-novo donor specific antibody (DSA) and outcomes after liver transplantation continues to be investigated.

RECENT FINDINGS

Consensus continues to evolve regarding the existence of acute and chronic antibody-mediated rejection (AMR) and pathogenicity of DSA and associated pathologic findings after liver transplantation. The presence of persistent high level, complement fixing DSA or emergence of de novo, Class II DSA has been associated with rejection and worse long-term graft and patient survival. Significant adverse associations of DSA extend to patients after simultaneous liver kidney (SLK) transplant as well as in pediatric recipients of liver transplantation. A higher degree of HLA incompatibility has been recently associated with worse outcomes in living donor liver transplant.

SUMMARY

In summary, recent consensus guidelines describe and recognize the existence of acute and chronic AMR and provide a basis upon which to build further investigation. Important adverse outcomes including decreased survival, allograft failure and liver fibrosis have been linked to the presence of DSA. Routine donor and recipient HLA typing and DSA assessment will facilitate diagnosis and provide for baseline data, which may help guide future management. Future investigations may help to clarify the role of therapeutic interventions.

Utility in Treating Kidney Failure in End-Stage Liver Disease With Simultaneous Liver-Kidney Transplantation

Background

Simultaneous liver-kidney (SLK) transplantation plays an important role in treating kidney failure in patients with end-stage liver disease. It used 5% of deceased donor kidney transplanted in 2015. We evaluated the utility, defined as posttransplant kidney allograft lifespan, of this practice.

Methods

Using data from the Scientific Registry of Transplant Recipients, we compared outcomes for all SLK transplants between January 1, 1995, and December 3, 2014, to their donor-matched kidney used in kidney-alone (Ki) or simultaneous pancreas kidney (SPK) transplants. Primary outcome was kidney allograft lifespan, defined as the time free from death or allograft failure. Secondary outcomes included death and death-censored allograft failure. We adjusted all analyses for donor, transplant, and recipient factors.

Results

The adjusted 10-year mean kidney allograft lifespan was higher in Ki/SPK compared with SLK transplants by 0.99 years in the Model for End-stage Liver Disease era and 1.71 years in the pre-Model for End-stage Liver Disease era. Death was higher in SLK recipients relative to Ki/SPK recipients: 10-year cumulative incidences 0.36 (95% confident interval 0.33-0.38) versus 0.19 (95% confident interval 0.17-0.21).

Conclusions

SLK transplantation exemplifies the trade-off between the principles of utility and medical urgency. With each SLK transplantation, about 1 year of allograft lifespan is traded so that sicker patients, that is, SLK transplant recipients, are afforded access to the organ. These data provide a basis against which benefits derived from urgency-based allocation can be measured.

This analysis of the UNOS data demonstrated that SLK patients had decreased long term renal graft function that SPK patients. This analysis demonstrates the difficult policy choices epitomized by prioritizing the SLK population and its impact of utility considerations. Supplemental digital content is available in the text.

[Caracterization of HLA allo-immunization and clinical impact in transfusion and organ transplantation]

Allo-immunizations against HLA antigens are known to be deleterious in transfusion and organ transplantation. The development of new tests based on solid phase assays for screening and identification of HLA antibodies in particular those using Luminex^® bead based technology has completely changed the way of allo-immunization monitoring because of their extreme sensitivity. They allow a better characterization of these antibodies, identification of acceptable antigens and the use of virtual cross-matches. All these new possibilities improve the managing of patients before and after platelets transfusion or organ transplantation. However, this technology displays some limits that should be known in order to interpret correctly the results. Beside these bead based assays, cellular cross-matches based on Complement Dependent Cytotoxicity (CDC) and flow cytometry are still used and useful in organ transplantation since beads are produced in vitro and do not reflected exactly what happens physiologically. Moreover, differences of sensitivity between these methods make results interpretation and decision making difficult in some cases.

Prevalence and Clinical Impact of Donor-Specific Alloantibody Among Intestinal Transplant Recipients

BACKGROUND

Rejection remains the leading cause of allograft loss, and a major barrier to improving long-term outcomes after intestinal transplantation. Our aim is to define the prevalence and investigate the role of donor-specific antibody (DSA) on intestinal graft outcomes.

METHODS

The study includes 109 transplants performed in 95 recipients at a single center. Patients were screened for DSA pretransplant, monitored regularly posttransplant and when clinically indicated using the single-antigen bead Luminex assay. Standard induction immunosuppression was with interleukin-2 receptor antagonists, and antithymocyte globulin in high-risk recipients. Maintenance regimens were tacrolimus-based.

RESULTS

Pretransplant DSA was detected in 12 (11%) recipients with 50% continuing to have circulating antibodies posttransplant. An additional 24 (25%) patients developed de novo DSA, and of these, 71% had persistent antibodies. Recipients with preformed DSA demonstrated elevated risks of early graft failure, whereas those with de novo DSA experienced accelerated graft loss once DSA was detected, reaching a 28% failure rate within 2 years. HLA-DQ mismatch is a significant risk factor for de novo DSA emergence, whereas the persistence of antibodies is predicted by DSA strength and specificity. Although inclusion of the liver in the intestinal allograft imparts an immunological advantage against rejection-related graft loss, this protective effect was lost among recipients with persistent DSA.

CONCLUSIONS

The presence of DSA is associated with inferior graft outcomes among intestinal transplant recipients. An enhanced understanding of the mechanisms by which DSA causes allograft injury, and effective strategies targeting humoral immune reactivity are needed to improve long-term intestinal graft outcomes.

Longterm renal allograft survival after sequential liver-kidney transplantation from a single living donor

Combined liver-kidney transplantation (CLKT) is well established as a definitive therapy with the potential to provide complete recovery for certain liver-kidney diseases, although the results might be contingent on the cause of transplantation. The purposes of the present study were to review the longterm outcome of renal allografts in CLKT patients from single living donors and to investigate the beneficial factors, compared with solitary renal transplantation. Thirteen patients underwent sequential liver transplantation (LT) and kidney transplantation (KT) from single living donors. The indications for KT were oxaluria (n = 7), autosomal recessive polycystic disease (n = 3), and others (n = 3). The same immunosuppressive regimen used after LT was also used after KT. KT was performed between 1.7 and 47.0 months after the LT. The overall patient survival rate was 92.3% at 10 years. In 12 of the 13 surviving patients, the renal allografts were found to be functioning in 11 patients after a mean follow-up period of 103.6 months. The death-censored renal allograft survival rate at 10 years was 100%, which was better than that of KT alone (84.9%) in Japan. Immunological protection conferred by the preceding liver allograft may have contributed to the longterm outcomes of the renal allografts. In addition, the donation of double organs from a single living and related donor may have a favorable impact on the graft survival rate. In the future, investigations of factors affecting the longterm outcome of renal allografts, including details of the involvement of de novo donor-specific antibody, will be needed. Liver Transplantation 23 315-323 2017 AASLD.

Five-year histological and serological follow-up of operationally tolerant pediatric liver transplant recipients enrolled in WISP-R

Pediatric liver transplant recipients arguably have the most to gain and the most to lose from discontinuing immunosuppression (IS). Whereas IS undoubtedly exerts a cumulative toll, there is concern that insufficient or no IS may contribute to allograft deterioration. Twelve pediatric recipients of parental living donor liver grafts, identified as operationally tolerant through complete IS withdrawal (WISP-R; NCT00320606), were followed for a total of 5 years (1 year of IS withdrawal and 4 years off IS) with serial liver tests and autoantibody and alloantibody assessments. Liver biopsies were performed 2 and 4 years off IS, and, at these time points, immunoglobulin G (IgG) subclass and C1q binding activity for donor-specific antibodies (DSAs) were determined. There were no cases of chronic rejection, graft loss, or death. Allografts did not exhibit progressive increase in inflammation or fibrosis. Smooth-muscle actin expression by stellate cells and CD34 expression by liver sinusoidal endothelial cells remained stable, consistent with the absence of progressive graft injury. Three subjects never exhibited DSA. However, 3 subjects showed intermittent de novo class I DSA, 4 subjects showed persistent de novo class II DSA, and 5 subjects showed persistent preexisting class II DSA. Class II DSA was predominantly against donor DQ antigens, often of high mean fluorescence intensity, rarely of the IgG3 subclass, and often capable of binding C1q.

CONCLUSION

Operationally tolerant pediatric liver transplant recipients maintain generally stable allograft histology in spite of apparently active humoral allo-immune responses. The absence of increased inflammation or progressive fibrosis suggests that a subset of liver allografts seem resistant to the chronic injury that is characteristic of antibody-mediated damage. (Hepatology 2017;65:647-660).

The Role of Humoral Alloreactivity in Liver Transplantation: Lessons Learned and New Perspectives

More than ten years after the initial description of the humoral theory of transplantation by Dr. Paul I. Terasaki, the significance of humoral alloimmunity in liver transplantation has yet to be clearly defined. The liver allograft has an inherent tolerogenic capacity which confers its resistance to cell-mediated as well as antibody-mediated rejection. Nevertheless, the protection against alloimmunity is not complete, and antibody-mediated tissue injury can occur in the liver graft under specific circumstances. In this article the evidence on the clinicopathologic effects of donor-specific alloantibodies in liver transplantation will be examined and interpreted in parallel with lessons learned from renal transplantation. The unique anatomic and immunologic features of the liver will be reviewed to gain new insights into the complex interactions between humoral immune system and the liver allograft.

Liver Allograft Provides Immunoprotection for the Cardiac Allograft in Combined Heart-Liver Transplantation

When transplanted simultaneously, the liver allograft has been thought to have an immunoprotective role on other organs; however, detailed analyses in simultaneous heart-liver transplantation (SHLT) have not been done to date. We analyzed patient outcomes and incidence of immune-mediated injury in 22 consecutive SHLT versus 223 isolated heart transplantation (IHT) recipients between January 2004 and December 2013, by reviewing 3912 protocol- and indication-specific cardiac allograft biopsy specimens. Overall survival was similar (86.4%, 86.4%, and 69.1% for SHLT and 93.3%, 84.7%, and 70.0% for IHT at 1, 5, and 10 years; p = 0.83). Despite similar immunosuppression, the incidence of T cell-mediated rejection (TCMR) was lower in SHLT (31.8%) than in IHT (84.8%) (p < 0.0001). Although more SHLT patients had preexisting donor-specific HLA antibody (22.7% versus 8.1%; p = 0.04), the incidence of antibody-mediated rejection was not different in SHLT compared with IHT (4.5% versus 14.8%, p = 0.33). While the left ventricular ejection fraction was comparable in both groups at 5 years, the incidence and severity of cardiac allograft vasculopathy were reduced in the SHLT recipients (42.9% versus 66.8%, p = 0.03). Simultaneously transplanted liver allograft was associated with reduced risk of TCMR (odds ratio [OR] 0.003, 95% confidence interval [CI] 0-0.02; p < 0.0001), antibody-mediated rejection (OR 0.04, 95% CI 0-0.46; p = 0.004), and cardiac allograft vasculopathy (OR 0.26, 95% CI 0.07-0.84; p = 0.02), after adjusting for other risk factors. These data suggest that the incidence of alloimmune injury in the heart allograft is reduced in SHLT recipients.

Successful Simultaneous Liver-Kidney Transplantation in the Presence of Multiple High-Titered Class I and II Antidonor HLA Antibodies

The results of simultaneous liver-kidney transplants in highly sensitized recipients have been controversial in terms of antibody-mediated rejection and kidney allograft outcomes. This case report provides a detailed and sophisticated documentation of histocompatibility and pathologic data in a simultaneous liver-kidney transplant performed in a recipient with multiple high-titered class I and II antidonor HLA antibodies and a strongly positive cytotoxic crossmatch. Patient received induction with steroids, rituximab, and eculizumab without lymphocyte depleting agents. The kidney transplant was delayed by 6 hours after the liver transplant to allow more time to the liver allograft to “absorb” donor-specific antibodies (DSA). Interestingly, the liver allograft did not prevent immediate antibody-mediated injury to the kidney allograft in this highly sensitized recipient. Anti-HLA single antigen bead analysis of liver and kidney allograft biopsy eluates revealed deposition of both class I and II DSA in both liver and kidney transplants during the first 2 weeks after transplant. Afterward, both liver and kidney allograft functions improved and remained normal after a year with progressive reduction in serum DSA values.