ABO-Incompatible Adult Living Donor Liver Transplantation in the Era of Rituximab: A Systematic Review and Meta-Analysis. Gastroenterol Res Pract. 2019;2019:8589402. [PMID: 31285743 PMCID: PMC6594289 DOI: 10.1155/2019/8589402]

The suggestion of mitigating disparity in the liver transplantation field among ABO blood type

Medical literature highlights differences in liver transplantation (LT) waitlist experiences among ABO blood types. Type AB candidates reportedly have higher LT rates and reduced mortality. Despite liver offering guidelines, ABO disparities persist. This study examines LT access discrepancies among blood types, focusing on type AB, and seeks equitable strategies. Using the United Network for Organ Sharing database (2003-2022), 170 276 waitlist candidates were retrospectively analyzed. Dual predictive analyses (LT opportunity and survival studies) evaluated 1-year recipient pool survival, considering waitlist and post-LT survival, alongside anticipated allocation value per recipient, under 6 scenarios. Of the cohort, 97 670 patients (57.2%) underwent LT. Type AB recipients had the highest LT rate (73.7% vs 55.2% for O), shortest median waiting time (90 vs 198 days for A), and lowest waitlist mortality (12.9% vs 23.9% for O), with the lowest median model for end-stage liver disease-sodium (MELD-Na) score (20 vs 25 for A/O). The LT opportunity study revealed that reallocating type A (or A and O) donors originally for AB recipients to A recipients yielded the greatest reduction in disparities in anticipated value per recipient, from 0.19 (before modification) to 0.08. Meanwhile, the survival study showed that ABO-identical LTs reduced disparity the most (3.5% to 2.8%). Sensitivity analysis confirmed these findings were specific to the MELD-Na score < 30 population, indicating current LT allocation may favor certain blood types. Prioritizing ABO-identical LTs for MELD-Na score < 30 recipients could ensure uniform survival outcomes and mitigate disparities.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Biliary complications after adult-to-adult living-donor liver transplantation: An international multicenter study of 3633 cases

In living-donor liver transplantation, biliary complications including bile leaks and biliary anastomotic strictures remain significant challenges, with incidences varying across different centers. This multicentric retrospective study (2016-2020) included 3633 adult patients from 18 centers and aimed to identify risk factors for these biliary complications and their impact on patient survival. Incidences of bile leaks and biliary strictures were 11.4% and 20.6%, respectively. Key risk factors for bile leaks included multiple bile duct anastomoses (odds ratio, [OR] 1.8), Roux-en-Y hepaticojejunostomy (OR, 1.4), and a history of major abdominal surgery (OR, 1.4). For biliary anastomotic strictures, risk factors were ABO incompatibility (OR, 1.4), blood loss >1 L (OR, 1.4), and previous abdominal surgery (OR, 1.7). Patients experiencing biliary complications had extended hospital stays, increased incidence of major complications, and higher comprehensive complication index scores. The impact on graft survival became evident after accounting for immortal time bias using time-dependent covariate survival analysis. Bile leaks and biliary anastomotic strictures were associated with adjusted hazard ratios of 1.7 and 1.8 for graft survival, respectively. The study underscores the importance of minimizing these risks through careful donor selection and preoperative planning, as biliary complications significantly affect graft survival, despite the availability of effective treatments.

The role of Roux-en-Y hepaticojejunostomy for the management of biliary complications after living donor liver transplantation

INTRODUCTION

Post living donor liver transplantation (LDLT) biliary complications can be troublesome over the post-operative course of patients, especially those with recurrent cholangitis or choledocholithiasis. Thus, in this study, we aimed to evaluate the risks and benefits of Roux-en-Y hepaticojejunostomy (RYHJ) performed after LDLT as a last option to deal with post-LDLT biliary complications.

METHODS

Retrospectively, of the 594 adult LDLTs performed in a single medical center in Changhua, Taiwan from July 2005 to September 2021, 22 patients underwent post-LDLT RYHJ. Indications for RYHJ included choledocholithiasis formation with bile duct stricture, previous intervention failure, and other factors. Restenosis was defined if further intervention was needed to treat biliary complications after RYHJ was performed. Thereafter, patients were categorized into success group (n = 15) and restenosis group (n = 4).

RESULTS

The overall success rate of RYHJ in the management of post-LDLT biliary complications was 78.9% (15/19). Mean follow-up time was 33.4 months. As per our findings, four patients experienced recurrence after RYHJ (21.2%), and mean recurrence time was 12.5 months. Three cases were recorded as hospital mortality (13.6%). Outcome and risk analysis presented no significant differences between the two groups. A higher risk of recurrence tended to be related to patients with ABO incompatible (ABOi).

CONCLUSION

RYHJ served well as either a rescue but definite procedure for recurrent biliary complications or a safe and effective solution to biliary complications after LDLT. A higher risk of recurrence tended to be related to patients with ABOi; however, further research would be needed.

Multimodal Management for Refractory Biliary Stricture After Living Donor Liver Transplantation

BACKGROUND

Biliary stricture is a common complication of living donor liver transplantation (LDLT). Endoscopic retrograde biliary drainage (ERBD) is the primary treatment of biliary stricture, which is sometimes refractory. This study aimed to evaluate the risk factors for biliary stricture after LDLT and present successful management for refractory biliary stricture.

METHODS

Data from 26 patients who underwent LDLT were retrospectively analyzed. The relationship between the incidence of biliary strictures and clinical variables, including pre/intra/postoperative factors, was assessed.

RESULTS

Univariate analysis showed that ABO incompatibility (P = .037) was a significant risk factor for biliary strictures. Case 1 was a 57-year-old woman who underwent LDLT using a left-lobe graft for primary biliary cholangitis (PBC) and developed a biliary stricture 1 month after surgery. Percutaneous transhepatic cholangiodrainage (PTCD) and embolization of the portal vein and hepatic artery were performed. Thereafter, ethanol was injected into the biliary duct, and the intervention was successfully completed. Case 2 was a 54-year-old woman who underwent LDLT using a right-lobe graft and duct-to-duct biliary reconstruction for PBC. Internal plastic stent insertion by ERBD was unsuccessful due to the significantly bending bile duct. After PTCD, the gun-site technique for the posterior branch and dual hepatic vascular embolization of the anterior branch was performed. The patient was followed up without an external fistula tube.

CONCLUSION

ABO incompatibility was a risk factor for refractory biliary stricture. Appropriate procedures should be chosen based on stricture types.

The fate of donor-type ABO blood group antigen expression in liver grafts in ABO-incompatible adult living donor liver transplantation

BACKGROUND/PURPOSE

Donor-type ABO blood group antigens (dABOAgs) have been detected in ABO-incompatible adult living donor liver transplantation (ABOi ALDLT) grafts, but their fate and role in ABOi ALDLT rejection remain uncertain.

METHODS

The 0-day, <1-month, and 1-year serial liver graft biopsies from 30 ABOi ALDLT recipients were retrospectively evaluated. ABO antigen expression was quantitatively and serially measured by the mean number of positively stained vascular structures (endothelium of the capillaries, arteries, hepatic veins, and portal veins) within the portal tracts (sS).

RESULTS

The dABOAg sS counts of 0-day, <1-month, and 1-year liver graft biopsies (32.3, 20.8, and 20.6, respectively) decreased significantly (p < .001). Early rejection in the <1-month biopsy was observed in 8/30 (26.7%) recipients, four (13.3%) of whom showed antibody-mediated rejection. The sS counts tended to rebound in grafts showing early rejection, with minimal changes from the 0-day to <1-month period, but increased to pre-transplantation levels after 1 year, compared to that in grafts without early rejection (36.0, 20.4, 19.6 vs. 23.7, 21.9, 23.0, respectively; p = .040).

CONCLUSIONS

While dABOAg expression decreased after ABOi ALDLT, recipients showing early rejection showed sustained graft dABOAg expression. Therefore, dABOAg expression may be involved in the mechanism of accommodation in ABOi transplantation.

Antiviral prophylaxis or preemptive therapy for cytomegalovirus after liver transplantation?: A systematic review and meta-analysis

BACKGROUND

To conduct a meta-analysis with the aim of comparing the outcomes of antiviral prophylaxis and preemptive therapy for the prevention of cytomegalovirus (CMV) infection in liver transplant (LT) recipients.

METHODS

We searched databases for qualified studies up until March 2022. Finally, a meta-analysis was carried out using a fixed-effect or random-effect model based on the heterogeneity.

RESULTS

With a total of 1834 LT patients, the pooled incidence of CMV infection and CMV disease in the overall LT recipients using antiviral prophylaxis and preemptive therapy were 24.7% vs. 40.4% and 6.4% vs. 9.4%, respectively. Our meta-analysis exhibited a significant reduction in the incidence of CMV infection due to antiviral prophylaxis when compared to preemptive therapy in the high-risk group (OR: 6.67, 95% CI: 1.73, 25.66; p = 0.006). In contrast, there was a significant reduction in the incidence of late-onset of CMV disease in preemptive therapy compared to antiviral prophylaxis in the high-risk group (OR: 0.29, 95% CI: 0.12, 0.74; p = 0.009). However, the incidence of CMV disease, allograft rejection, graft loss, drug related adverse effects, opportunistic infections and mortality did not differ significantly between both the interventions (all p> 0.05).

CONCLUSIONS

We found the use of antiviral prophylaxis, compared with preemptive therapy, is superior in controlling CMV infection and prolonging the time to CMV disease in LT recipients without an increased risk of opportunistic infections, allograft rejection, graft loss, drug related adverse effects, development of drug resistance, and mortality.

Immunosuppressive Drugs in Liver Transplant: An Insight

Liver transplantation (LT) is the standard of care for end-stage liver failure and hepatocellular carcinoma. Over the years, immunosuppression regimens have improved, resulting in enhanced graft and patient survival. At present, the side effects of immunosuppressive agents are a significant threat to post-LT quality of life and long-term outcome. The role of personalized immunosuppression is to reach a delicate balance between optimal immunosuppression and minimal side effects. Today, immunosuppression in LT is more of an art than a science. There are no validated markers for overimmunosuppression and underimmunosuppression, only a few drugs have therapeutic drug monitoring and immunosuppression regimens vary from center to center. The immunosuppressive agents are broadly classified into biological agents and pharmacological agents. Most regimens use multiple agents with different modes of action to reduce the dosage and minimize the toxicities. The calcineurin inhibitor (CNI)-related toxicities are reduced by antibody induction or using mTOR inhibitor/antimetabolites as CNI sparing or CNI minimization strategies. Post-liver transplant immunosuppression has an intensive phase in the first three months when alloreactivity is high, followed by a maintenance phase when immunosuppression minimization protocols are implemented. Over time some patients achieve "tolerance," defined as the successful stopping of immunosuppression with good graft function and no indication of rejection. Cell-based therapy using immune cells with tolerogenic potential is the future and may permit complete withdrawal of immunosuppressive agents.

Massive Polycystic Liver with a Poor Performance Status Successfully Treated by ABO-incompatible Adult Living-donor Liver Transplantation While Overcoming Complications

We encountered a 47-year-old woman with polycystic liver disease (PLD) and severe malnutrition successfully treated by living-donor liver transplantation (LDLT). Her PLD became symptomatic with abdominal distension and appetite loss. Transcatheter arterial embolization and percutaneous cyst drainage failed to improve her symptoms. ABO-incompatible LDLT from her husband was performed after rituximab administration and mycophenolate mofetil introduction. Although she showed severe postoperative complications, she ultimately regained the ability to walk and was discharged. Because advanced PLD cases are difficult to treat conservatively or with surgery, like fenestration and hepatectomy, liver transplantation should be considered before it becomes too late.

When Push Comes to Shove! Emergency ABO-Incompatible Pediatric Living Donor Liver Transplant for Acute Wilson's Disease

ABO-incompatible living donor liver transplantation (ABOi-LDLT) is on the rise as a viable option in countries with limited access to deceased donor grafts. While reported outcomes of ABOi-LT in children are similar to ABO- Compatible liver transplant (ABOc-LT), most children beyond 1-2 years of age will need desensitization to overcome the immunological barrier of incompatible blood groups. The current standard protocol for desensitization is Rituximab that targets B lymphocytes and is given 2-3 weeks prior to LT. However, this timeline may not be feasible in children requiring emergency LT for acute liver failure (ALF) or acute-on-chronic liver failure (ACLF). In this emergency situation of ABOi-LT, a safe multipronged approach may be an acceptable alternative solution. We report a child with acute Wilson's disease with rapidly deteriorating liver function who underwent a successful ABOi-LDLT using a rapid desensitization protocol.

Quick preparation of ABO-incompatible living donor liver transplantation for acute liver failure

Acute liver failure is life-threatening and has to be treated by liver transplantation urgently. When deceased donors or ABO-compatible living donors are not available, ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) becomes the only choice. How to prepare ABO-I LDLT urgently is an unsolved issue. A quick preparation regimen was designed, which was consisted of bortezomib (3.5mg) injection to deplete plasma cells and plasma exchange to achieve isoagglutinin titer ≤ 1: 64 just prior to liver transplantation and followed by rituximab (375mg/m² ) on post-operative day one to deplete B-cells. Eight patients received this quick preparation regimen to undergo ABO-I LDLT for acute liver failure from 2012 to 2019. They aged between 50 and 60 years. The median MELD score was 39 with a range from 35 to 48. It took 4.75 ± 1.58 days to prepare such an urgent ABO-I LDLT. All the patients had successful liver transplantations, but one patient died of antibody-mediated rejection at post-operative month 6. The 3-month, 6-month, and 1-year graft/patient survival were 100%, 87.5%, and 75%, respectively. In conclusion, this quick preparation regimen can reduce isoagglutinin titers quickly and make timely ABO-I LDLT feasible for acute liver failure. This article is protected by copyright. All rights reserved.

Clinical Relevance of Isoagglutinin Rebound in Adult ABO-Incompatible Living Donor Liver Transplantation

ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) can be performed successfully. However, anti-ABO isoagglutinin rebound may cause antibody-mediated rejection (AMR) and graft loss. The risk threshold of isoagglutinin rebound is still not defined. 76 ABO-I LDLT recipients were divided into group A (n = 56) with low isoagglutinin titers (<1:256), and group B (n = 20) with high isoagglutinin titers (≥1:256), at initial assessment for liver transplantation. The last 12 patients in group B received a modified desensitization regimen by adding bortezomib to deplete plasma cells. Six (10.7%) patients in group A and 10 (50.0%) patients in group B had postoperative isoagglutinin rebound (p < 0.001). Three patients (5.54%) in group A and two patients (10%) in group B developed clinical AMR (p = 0.602). The cutoff value of postoperative isoagglutinin rebound to cause clinical AMR was ≥1:1024. Among the 12 patients in group B with bortezomib administration, isoagglutinin rebounded up to 1:128 only, and no clinical AMR occurred. In conclusion, the patients with high isoagglutinin titers had a higher rate of postoperative isoagglutinin rebound. Isoagglutinin rebound ≥1:1024 is risky for developing clinical AMR. Adding bortezomib into the desensitization regimen may mitigate isoagglutinin rebound, and avoid clinical AMR.

Can Microscopic Biliary Reconstruction Reduce Biliary Complication Rate in ABO-Incompatible Adult Living Donor Liver Transplantation?

Background

With the introduction of rituximab, ABO-incompatible (ABOi) living donor liver transplantation (LDLT) has been considered a feasible and safe procedure to overcome the shortage of organ donors. However, higher biliary complication rates remain an unresolved problem in the ABOi group. In our center, biliary anastomosis has been done with microscopic biliary reconstruction (MBR), which effectively reduced the biliary complication rate. The aim of the current study was to investigate whether the microscopic approach reduced anastomotic biliary complications in ABOi LDLT.

Material/Methods

From March 2006 to December 2018, 30 adult ABOi and 60 ABO-compatible (ABOc) LDLT patients were selected from over 1300 recipients through 1: 2 propensity score-matched cohorts. All patients received MBR during the transplantation. Biliary complications included bile leakage and biliary stricture. Patients with diffuse intrahepatic biliary stricture were excluded from analysis.

Results

Patient characteristics were similar in the 2 groups. There was no in-hospital mortality in the ABOi LDLT. The long-term survival rates of the ABOi patients were comparable to those of the patients that underwent ABOc LDLT (87.1% vs 87.4%, P=0.964). Those in the ABOi group with anastomotic biliary complications were about 40%, which was higher than in the ABOc patients (40% vs 15%, P=0.01).

Conclusions

Microscopic biliary reconstruction does not help to reduce the high biliary complication rate in ABOi LDLT. Further investigation and identification regarding other risk factors and precautionary measures involving immunologic and adaptation mechanisms are needed.

Assessment of the global practice of living donor liver transplantation

Criteria that drive the selection and utilization of living liver donors are limited. Herein, the global availability of living donor liver transplantation (LDLT) and components of donor selection and utilization were assessed via an international survey. There were 124 respondents representing 41 countries, including 47 from Asia/Middle East (A/ME), 20 from Europe, and 57 from the Americas. Responses were obtained from 94.9% of countries with ≥10 LDLT cases/year. Most centers (82.3%) have defined donor age criteria (median 18-60 years), while preset recipient MELD cutoffs (median 18-30) were only reported in 54.8% of programs. Overall, 67.5% of programs have preset donor BMI (body mass index) ranges (median 18-30), and the mean acceptable macrosteatosis was highest for A/ME (20.2 ± 9.2%) and lowest for Americas (16.5 ± 8.4%, P = 0.04). Americas (56.1%) and European (60.0%) programs were more likely to consider anonymous donors versus A/ME programs (27.7%, P = 0.01). There were no differences in consideration of complex anatomical variations. Most programs (75.9%) perform donor surgery via an open approach, and A/ME programs are more likely to use microscopic arterial reconstruction. Despite variations in practice, key aspects of living donor selection were identified. These findings provide a contemporary reference point as LDLT continues to expand into areas with limited access to liver transplantation.

Expanding Donor Selection and Recipient Indications for Living Donor Liver Transplantation

There is an acute shortage of deceased donor organs for liver transplantation in the United States. Nearly a third of patients either die or become too sick for transplant while on the transplant waitlist. Living donor liver transplantation (LDLT) bridges the gap between demand and supply of organs for liver transplantation. This article reviews current living donor selection criteria, and avenues for expansion of criteria with novel surgical techniques and ongoing outcomes research. Ways in which institutions can establish and expand LDLT programs using the Living Donor Champion model are discussed. Efforts to expand recipient indications for LDLT are described.

Successful ABO-incompatible living donor liver transplantation using splenectomy and intravenous immunoglobulin in high isoagglutinin titer patients

The role of the isoagglutinin (IA) titer in liver transplantation (LT) is still not well defined, but the general belief is that a higher titer may result in a higher risk of rejection in ABO-incompatible living donor LT. To reduce the IA titer by 1:16 or lower, plasmapheresis is usually performed before transplantation. However, there is no established protocol for patients for whom plasmapheresis has failed before reaching the target IA titers. Here, we report the cases of three patients who show high baseline IA titers and have failed plasmapheresis: no-response to plasmapheresis, allergic reaction associated with plasmapheresis, and anaphylactic reaction to platelet transfusion. For various reasons, after several plasmapheresis procedures, IA titers were not effectively reduced. In these patients, splenectomy and intravenous immunoglobulin (0.8 g/kg, from the anhepatic phase to 2 days after transplantation) were carried. The protocol biopsy on postoperative day 7 showed no histologic evidence of meaningful acute rejection. The main aim of this work is to demonstrate that we can apply this protocol to patients who have high baseline IA titers and have failed plasmapheresis. Furthermore, this report is enhanced to promote to the transplant community this approach with this type of recipient.

The Human Immune Response to Cadaveric and Living Donor Liver Allografts

The liver is an important contributor to the human immune system and it plays a pivotal role in the creation of both immunoreactive and tolerogenic conditions. Liver transplantation provides the best chance of survival for both children and adults with liver failure or cancer. With current demand exceeding the number of transplantable livers from donors following brain death, improved knowledge, technical advances and the desire to prevent avoidable deaths has led to the transplantation of organs from living, ABO incompatible (ABOi), cardiac death donors and machine based organ preservation with acceptable results. The liver graft is the most well-tolerated, from an immunological perspective, of all solid organ transplants. Evidence suggests successful cessation of immunosuppression is possible in ~20–40% of liver transplant recipients without immune mediated graft injury, a state known as “operational tolerance.” An immunosuppression free future following liver transplantation is an ambitious but perhaps not unachievable goal. The initial immune response following transplantation is a sterile inflammatory process mediated by the innate system and the mechanisms relate to the preservation-reperfusion process. The severity of this injury is influenced by graft factors and can have significant consequences. There are minimal experimental studies that delineate the differences in the adaptive immune response to the various forms of liver allograft. Apart from ABOi transplants, antibody mediated hyperacute rejection is rare following liver transplant. T-cell mediated rejection is common following liver transplantation and its incidence does not differ between living or deceased donor grafts. Transplantation in the first year of life results in a higher rate of operational tolerance, possibly due to a bias toward Th2 cytokines (IL4, IL10) during this period. This review further describes the current understanding of the immunological response toward liver allografts and highlight the areas of this topic yet to be fully understood.

ABO-nonidentical liver transplantation from a deceased donor and clinical outcomes following antibody rebound: A case report

BACKGROUND

Although ABO-nonidentical and ABO-incompatible liver transplantation (LT) are other options for end-stage liver disease treatment, the development of antibodies against blood group antigens (anti-A/B antibodies) is still a challenge in managing and follow-up of the recipients.

CASE SUMMARY

A 56-year-old male with end-stage liver disease with rapid deterioration and poor prognosis was considered to receive a deceased ABO-nonidentical liver graft. All required tests were performed according to our pre-LT diagnostic protocol. The orthotopic LT procedure involving O+ donor and A1B+ recipient was performed. Our treatment strategy to overcome the antibody‐mediated rejection included a systemic triple immunosuppressive regimen: methylprednisolone, mycophenolate mofetil, and tacrolimus. The immunological desensitization consisted of the chimeric anti-CD20 monoclonal antibody rituximab and intravenous immunoglobulins. The patient was also on antibiotic treatment with amoxicillin/clavulanate, cefotaxime, and metronidazole. On the 10^th postoperative day, high titers of IgG anti-A and anti-B antibodies were found in the patient’s plasma. We performed a liver biopsy, which revealed histological evidence of antibody-mediated rejection, but the rejection was excluded according to the Banff classification. The therapy was continued until the titer decreased significantly on the 18^th postoperative day. Despite the antibiotic, antifungal, and antiviral treatment, the patient deteriorated and developed septic shock with anuria and pancytopenia. The conservative treatment was unsuccessful, which lead to the patient’s fatal outcome on the 42^nd postoperative day.

CONCLUSION

We present a patient who underwent ABO-nonidentical LT from a deceased donor. Even though we implemented the latest technological advancements and therapeutic approaches in the management of the patient and the initial results were promising, due to severe infectious complications, the outcome was fatal.