Relevance of HLA compatibility in living donor liver transplantation: the double-edged sword associated with the patient outcome

The Consequences of HLA Screening in the Prevention of Graft-Versus-Host Disease in Living Donor Liver Transplantation

AIMS

To study the effects of routine HLA screening and the policy of avoiding donor-dominant one-way HLA match to prevent graft-versus-host disease (GVHD) after living donor liver transplantation (LDLT).

PATIENTS AND METHODS

The records of potential living liver donors and recipients who attended our center between 2007 and 2018 were reviewed retrospectively.

RESULTS

Of the 149 patients who underwent LDLT and survived longer than 3 months, two developed GVHD despite our strict policy. The first patient presented with grade II GVHD limited to the skin. She was treated successfully by briefly discontinuing immunosuppression and switching to everolimus. In the second case, the policy had been relaxed due to the availability of a single donor for ABO-incompatible transplantation without any intervention to decrease anti-A antibody levels (special case: A2 to O). Nevertheless, the patient presented with grade I GVHD limited to skin and was treated successfully by adding oral methylprednisolone to tacrolimus and mycophenolate mofetil. To the best of our information, this is the second reported case who recovered from GVHD after LDLT from a donor, homozygous at HLA A, B and DR and a recipient, heterozygous for all. Sixteen potential donors (1.2% of all candidates) of 14 recipients were disqualified solely on the basis of the HLA results; five of these patients died due to unavailability of another donor.

CONCLUSION

The results support the policy of avoiding HLA combinations that preclude immune recognition of graft lymphocytes as foreign to decrease the risk of GVHD after LDLT.

One-way donor-to-recipient human leukocyte antigen mismatch and graft-versus-host disease in liver transplantation: an observational study of a single-center experience in Korea

Background

Graft-versus-host disease (GVHD) is a rare, but potentially fatal complication of liver transplantation. One-way human leukocyte antigens (HLA) mismatch has emerged as a risk factor for GVHD. However, the risk of mortality associated with HLA-one-way mismatch (OWMM) remains uncertain. We investigated the incidence and characteristics of GVHD.

Methods

In total, 899 patients who underwent liver transplantation at a single center were retrospectively reviewed. The incidence of GVHD and 1- and 5-year survival rates were compared according to whether HLA-OWMM developed.

Results

In the HLA-OWMM group, GVHD developed in two patients (14.3%). Notably, GVHD was only observed in living donor liver transplant (LDLT) recipients in the HLA-OWMM group. The HLA-OWMM group exhibited a lower 1-year patient survival rate than the control (i.e., non-HLA-OWMM) group (78.6% vs. 90.7%, P=0.120). However, the 5-year survival rate in the HLA-OWMM group was similar to that in the control group (78.6% vs. 78.2%, P=0.821). When the HLA-OWMM group was further stratified by the number of mismatched loci, the 5-year survival rate was 83.3% in patients with HLA-OWMM at one to two loci and 75.0% in those with HLA-OWMM at three loci.

Conclusions

Despite the higher incidence of GVHD in LDLT recipients with HLA-OWMM, the 5-year patient survival rates were comparable to those in recipients without HLA-OWMM. The decision to perform LDLT in patients with HLA-OWMM depends on the patient's status and the organ supply of a specific region.

The effect of donor against recipient one-way HLA mismatch on liver transplantation outcomes from a multicenter registry analysis

Donor against recipient one-way Human leukocyte antigen (HLA) mismatch (D → R one-way HLA MM) seemed strongly associated with graft-versus-host disease (GVHD). The aim of this study is to investigate the relevance of D → R one-way HLA MM in outcome of liver transplantation (LT). We retrospectively analyzed 2670 patients in Korean Organ Transplantation Registry database between April 2014 and December 2020. The patients were categorized into two groups whether D → R one-way HLA MM or not and evaluated the outcomes of LT between the two groups. 18 patients were found to be D → R one-way HLA MM. The incidence of GVHD (0.3% vs. 22.2%, p < 0.001) and mortality rate (11.6% vs. 38.9%, p = 0.003) was much higher in D → R one-way HLA MM group. D → R one-way HLA MM at 3 loci was seemed to be strongly associated with the incidence of GVHD (OR 163.3, p < 0.001), and found to be the strongest risk factor for patient death (HR 12.75, p < 0.001). Patients with D → R one-way HLA MM at 3 loci showed significantly lower overall survival (p < 0.001) but there were no significant differences in rejection-free survival and death-censored graft survival. D → R one-way HLA MM at 3 loci not only affects the overall survival of LT patients but also the incidence of GVHD.

The clinical impact of donor against recipient HLA one way mismatch on the occurrence of graft versus host disease in liver transplantation

Graft versus host disease (GVHD) after liver transplantation (LT) is a rare, fatal disease. This study aimed to evaluate the risk factors of GVHD after LT including the human leukocyte antigen (HLA) donor-recipient relationship after LT. LT recipients, who underwent HLA typing together with donors, were included in the study. The donor against recipient (D → R) one-way mismatch of HLA loci was evaluated. HLA relationships, along with basic characteristics, were analyzed as variable factors of GVHD, graft survival, and patient survival. A total of 994 living donor LT (LDLT) and 393 deceased donor LT (DDLT) patients were included. Nine patients had suffered GVHD, four LDLT with D → R one-way at three loci, one LDLT without D → R one-way at three loci, and four DDLT without D → R one-way at three loci. Four (57.1%) of seven LDLT patients, with D → R one-way mismatch at three loci, developed GVHD. D → R one-way mismatch at three loci was related to high GVHD incidence (HR 787, p < 0.001, multivariate). D → R one-way mismatch at three loci was related to graft failure and patient death (HR 9.90, p = 0.020 and HR 12.8, p < 0.001, respectively, multivariate). Only one GVHD without D → R one-way mismatch at three loci, survived despite receiving multiple modalities including tumor necrosis factor-alpha inhibitors. D → R one-way mismatch at three loci was significantly related to GVHD incidence after LT.

The incidence and risk factors of chronic rejection in acutely rejected pediatric liver transplantation

Background. Chronic graft rejection (CR) represents an increasing concern in pediatric liver transplantation (LT). Risk factors of CR in this population are uncertain. In present study, we aimed to ascertain if clinical parameters could predict the occurrence of CR in LT children.

Methods. We retrospectively analyzed the results from 47 children who had experienced acute hepatic rejection in Namazee hospital, Shiraz, Iran during 2007–2017.

Results. Out of 47 children, 22 (46.8%) and 25 (53.2%) were boys and girls respectively. Ascites, gastrointestinal bleeding, and spontaneous bacterial peritonitis were observed in 20 (44.4%), 14 (31.1%), and 4 (9.1%) respectively. Posttransplant vascular and biliary complications were observed in 3 (7%) and 4 (9.3%) cases respectively. The mean time from LT to normalization of liver enzymes was 14.2 ± 7.5 days. The mean of acute rejection episodes was 1.4 ± 0.6 (median = 1 (22, 46.8%), range of 1–3). Six (12.7%) patients experienced CR. The mean time from LT to CR was 75 ± 28.4 days. A significant association was found between CR and patients’ condition (being inpatient or outpatient) before surgery (P = 0.03). No significant relationship was found between CR and post-transplant parameters except for biliary complications (P = 0.01). Both biliary complication (RR = 33.7, 95% CI: 2.2–511, P = 0.01) and inpatient status (RR = 10.9, 95% CI: 1.1–102.5, P = 0.03) significantly increased the risk of CR.

Conclusion. Being hospitalized at the time of LT, and development of biliary complications might predict risk factors for development of CR in LT children.

Donor-dominant one-way matching of human leukocyte antigen-A/B/DR alleles predicts graft-versus-host disease following living donor liver transplantation

AIM

Graft-versus-host disease (GVHD) following liver transplantation is rare but fatal. Therefore, it is important to identify possible risk factors before transplantation. Although it has been suggested that donor-dominant one-way human leukocyte antigen (HLA) matching of three loci (HLA-A/B/DR) is associated with the occurrence of GVHD, the precise significance of HLA matching including HLA-C/DQ/DP remains unclear.

METHODS

We retrospectively analyzed the impact of donor-dominant one-way HLA matching at six HLA loci at the allele level on GVHD using clinical registry data from 1759 cases who underwent living donor liver transplantation between June 1990 and June 2019. We extracted cases with donor-dominant one-way HLA matching at the antigen level and reconfirmed them at the allele level using preserved DNA samples.

RESULTS

Three of four cases (75%) who developed GVHD showed donor-dominant one-way HLA matching at three HLA-A/B/DR loci. These cases also showed donor-dominant one-way HLA matching at HLA-C/DQ/DP. Three of six cases (50%) with donor-dominant one-way HLA matching at three loci of HLA-A/B/DR developed GVHD. Notably, none of the cases with donor-dominant one-way HLA matching at one or two HLA-A/B/DR loci developed GVHD, irrespective of matching status at HLA-C/DQ/DP. The HLA matching status at the antigen level was revised in 22 of 56 cases, following reconfirmation at the allele level.

CONCLUSIONS

Pairing of donors and recipients with donor-dominant one-way HLA matching at three HLA-A/B/DR loci should be avoided to prevent GVHD. No impact of HLA-C/DQ/DP on GVHD was identified. For liver transplantation, HLA genotypes should be determined at the allele level.

Understanding, predicting and achieving liver transplant tolerance: from bench to bedside

In the past 40 years, liver transplantation has evolved from a high-risk procedure to one that offers high success rates for reversal of liver dysfunction and excellent patient and graft survival. The liver is the most tolerogenic of transplanted organs; indeed, immunosuppressive therapy can be completely withdrawn without rejection of the graft in carefully selected, stable long-term liver recipients. However, in other recipients, chronic allograft injury, late graft failure and the adverse effects of anti-rejection therapy remain important obstacles to improved success. The liver has a unique composition of parenchymal and immune cells that regulate innate and adaptive immunity and that can promote antigen-specific tolerance. Although the mechanisms underlying liver transplant tolerance are not well understood, important insights have been gained into how the local microenvironment, hepatic immune cells and specific molecular pathways can promote donor-specific tolerance. These insights provide a basis for the identification of potential clinical biomarkers that might correlate with tolerance or rejection and for the development of novel therapeutic targets. Innovative approaches aimed at promoting immunosuppressive drug minimization or withdrawal include the adoptive transfer of donor-derived or recipient-derived regulatory immune cells to promote liver transplant tolerance. In this Review, we summarize and discuss these developments and their implications for liver transplantation.

Superior Outcomes and Reduced Wait Times in Pediatric Recipients of Living Donor Liver Transplantation

Background

Living donor liver transplantation (LDLT) is increasingly used to bridge the gap between the current supply and demand imbalance for deceased donor organs to provide lifesaving liver transplantation.

Methods

Outcomes of 135 children who underwent LDLT were compared with 158 recipients of deceased donor liver transplantation (DDLT) at the largest pediatric liver transplant program in Canada.

Results

Recipients of LDLT were significantly younger than deceased donor recipients (P ≤ 0.001), less likely to require dialysis pretransplant (P < 0.002) and had shorter wait time duration when the primary indication was cholestatic liver disease (P = 0.003). The LDLT donors were either related genetically or emotionally (79%), or unrelated (21%) to the pediatric recipients. One-, 5-, and 10-year patient survival rates were significantly higher in LDLT (97%, 94%, and 94%) compared with DDLT (92%, 87%, and 80%; log-rank P = 0.02) recipients, as were graft survival rates (96%, 93%, and 93% for LDLT versus 89%, 81.4%, and 70%, respectively, for DDLT; log-rank P = 0.001). Medical and surgical complications were not statistically different between groups. Graft failure was higher in recipients of DDLT (odds ratio, 2.60; 95% confidence interval, 1.02, 6.58) than in the LDLT group after adjustment for clinical characteristics and propensity score.

Conclusions

Living donor liver transplantation provides superior outcomes for children and is an excellent and effective strategy to increase the chances of receiving a liver transplant.

Human leukocyte antigen, allele, and eplet mismatches in liver transplantation; observations from a small, single center cohort

BACKGROUND

The impact of human leukocyte antigen (HLA) matching on outcomes in liver transplantation is controversial. Varying levels of HLA matching resolutions were examined in a uniform patient population with no pre-transplant DSA from a small, single center cohort.

METHODS

Retrospective chart review from a single center yielded 131 patients, 67 of which were confirmed to be DSA negative, all of which received induction immunotherapy and post-operative immunosuppression. HLA typing was achieved by sequence specific oligonucleotide probe (SSOP) method using LABType® kits. Eplet mismatch analysis was conducted using HLAMatchMaker software.

RESULTS

The mean number of HLA-A antigen mismatches was significantly higher in patients experiencing acute rejection (1.8 vs 1.6, p = 0.006). Rejection patients more frequently possessed two HLA-A mismatches compared to their non-rejection counterparts (77% vs 43%, p = 0.071). Patient survival was found to be non-significantly decreased in patients with a higher eplet mismatch load at the HLA-A locus (p = 0.155). No other loci were found to be predictive.

CONCLUSION

In conclusion, HLA mismatches were found to increase acute rejection and be associated with decreased patient survival. The outcomes of this study suggest an involvement of HLA-A locus mismatches in predicting liver transplant rejection and patient survival.

Elevated Soluble Platelet Glycoprotein VI Levels in Patients After Living Donor Liver Transplantation

Plasma-soluble platelet glycoprotein VI (sGPVI) levels were examined in patients undergoing living donor liver transplantation (LDLT), and the relationship between platelet activation and thrombocytopenia was evaluated to understand the mechanism of thrombocytopenia in LDLT. Platelet counts were significantly higher in the donors compared to the recipient, and the plasma sGPVI levels increased in both groups after the operation. Regarding the relationship between the platelet counts and the sGPVI levels, the slope varied on different days, and it became negative on day 3, suggesting that the plasma sGPVI levels are related to platelet activation in LDLT. The frequency of complications was high in the nonsurvivors. The platelet counts were higher in the survivors than in the nonsurvivors on days 14 and 28. Although the plasma levels of sGPVI in the survivors increased after the operation, those in the nonsurvivors were high only on day 3. Although the ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 domain, member 13) levels were markedly reduced, von Willebrand factor (VWF) and VWF propeptide (VWFpp) were markedly elevated during LDLT. The antithrombin activity was significantly lower (day 14) and VWFpp (day 28) was significantly higher in the nonsurvivors than in the survivors. These findings suggest that platelet activation first occurs after LDLT, and it is high in the nonsurvivors on day 3. Thereafter, the hemostatic abnormality and vascular endothelial cell injuries may appear on days 14 and 28.

Cytokine and human leukocyte antigen (HLA) profile for graft-versus-host disease (GVHD) after organ transplantation

BACKGROUND

Graft-versus-host disease (GVHD) after liver and kidney transplantation has high mortality and causes diagnostic challenges. This study aims to describe the cytokine and human leukocyte antigen (HLA) profile in the GVHD after liver and kidney transplantation.

METHODS

A high-throughput detection kit was applied and altogether 18 different cytokines were tested simultaneously. GVHD patients included 23 post-liver transplantation patients; 22 post-renal transplantation patients; The control patients include 22 hepatocellular carcinoma (HCC) patients without transplantation and 20 healthy controls. Their HLA characters were compared.

RESULTS

The full spectrum of cytokines was present. The inflammatory markers were activated significantly in liver transplantation. The level of inflammatory markers in liver transplantation was higher than that in renal transplantation, HCC or healthy controls. GVHD was associated with the HLA characters; HLA characters are involved in liver GVHD occurrence and act as risk factors.

CONCLUSION

Our findings confirmed that the inflammatory cytokines play a pathogenic role in GVHD and can be used as early diagnostic markers. The HLA mismatch acts as a risk factor in liver transplantation to predict GVHD occurrence.

Fatal Graft-Versus-Host Disease Following Adult-To-Adult Living Donor Liver Transplantation From an HLA Nonhomozygous Donor

The use of a human leukocyte antigen (HLA) homozygous donor to a haploidentical recipient is a well-documented cause of transfusion-associated graft-versus-host disease (GVHD). Several authors have reported that use of a graft from an HLA-homozygous donor with 1-way donor-recipient HLA matching led to an extremely high risk of developing GVHD in LDLT. We have experienced a fatal case of acute GVHD following adult-to-adult LDLT from a donor who was heterozygous at a single HLA locus. A 53-year-old female underwent LDLT for chronic hepatitis B and recurrent hepatocellular carcinoma. The donor was her 23-year-old son. The HLA phenotype of the donor was not homozygous (A24, -; B54, -; DR4, 9) and revealed one-way donor-dominant HLA matching at two loci with the recipient (A2, 24; B48, 54; DR4, 12). On the fortieth postoperative day, the patient showed erythematous skin lesions. Skin biopsy revealed typical findings of GVHD. Donor-derived chimerism was demonstrated by performing fluorescent in situ hybridization (FISH) using the recipient's skin tissue. As the clinical course deteriorated, etanercept was started in addition to broad-spectrum antibiotics but there was no improvement. As multi-organ failure progressed, the patient succumbed to death on the 54th postoperative day, which was 2 weeks after onset of GVHD. The prevention of GVHD is more important since the results of treatment have been disappointing. We have experienced a fatal case of acute GVHD following adult-to-adult LDLT from a HLA non-homozygous donor. HLA heterozygosity at a single locus does not preclude the possibility of developing GVHD following adult-to-adult LDLT.

Risk factors for early and late biliary complications in pediatric liver transplantation

BC are a common source of morbidity after pediatric LT. Knowledge about risk factors may help to reduce their incidence. Retrospective analysis of BC in 116 pediatric patients (123 LT) (single institution, 05/1990-12/2011, medium follow-up 7.9 yr). One-, five-, and 10-yr survival was 91.1%, no patient died of BC. Prevalence and risk factors for anastomotic and intrahepatic BC were examined. There were 29 BC in 123 LT (23.6%), with three main categories: 10 (8.1%) primary anastomotic strictures, eight (6.5%) anastomotic leaks, and three (2.4%) intrahepatic strictures. Significant risk factors for anastomotic leaks were total operation time (increase 1.26-fold) and early HAT (<30 days post-LT; increase 5.87-fold). Risk factor for primary anastomotic stricture was duct-to-duct choledochal anastomosis (increase 5.96-fold when compared to biliary-enteric anastomosis). Risk factors for intrahepatic strictures were donor age >48 yr (increase 1.09-fold) and MELD score >30 (increase 1.2-fold). To avoid morbidity from anastomotic BC in pediatric LT, the preferred biliary anastomosis appears to be biliary-enteric. Operation time should be kept to a minimum, and HAT must by all means be prevented. Children with a high MELD score or receiving livers from older donors are at increased risk for intrahepatic strictures.

Experimental orthotopic transplantation of a tissue-engineered oesophagus in rats

A tissue-engineered oesophageal scaffold could be very useful for the treatment of pediatric and adult patients with benign or malignant diseases such as carcinomas, trauma or congenital malformations. Here we decellularize rat oesophagi inside a perfusion bioreactor to create biocompatible biological rat scaffolds that mimic native architecture, resist mechanical stress and induce angiogenesis. Seeded allogeneic mesenchymal stromal cells spontaneously differentiate (proven by gene-, protein and functional evaluations) into epithelial- and muscle-like cells. The reseeded scaffolds are used to orthotopically replace the entire cervical oesophagus in immunocompetent rats. All animals survive the 14-day study period, with patent and functional grafts, and gain significantly more weight than sham-operated animals. Explanted grafts show regeneration of all the major cell and tissue components of the oesophagus including functional epithelium, muscle fibres, nerves and vasculature. We consider the presented tissue-engineered oesophageal scaffolds a significant step towards the clinical application of bioengineered oesophagi.

Revisiting the safety of living liver donors by reassessing 441 donor hepatectomies: is a larger hepatectomy complication-prone?

Donor safety is of paramount importance in performing living donor liver transplantation (LDLT). We retrospectively reviewed donor medical records to confirm whether larger donor hepatectomy is absolutely complication-prone. A total of 441 living donor hepatectomies were performed between October 1996 and July 2012 in our institute, which were divided into three eras (Era I, October 1996 to March 2004; Era II, April 2004 to March 2008; Era III, April 2008 to July 2012) and the incidences of postoperative complications were compared among the three types of hepatectomy-right hepatectomy (RH), left hepatectomy (LH) and left lateral segmentectomy (LLS). Although severe complications (Clavien's grade 3 or more) frequently occurred in RH in Eras I and II (15.4% and 10.7%, respectively), the incidence in Era III decreased to the comparable level observed in LH and LLS (5.4% in RH, 2.3% in LH and 5.3% in LLS). The incidence of postoperative complications did not relate to the type of hepatectomy selected in the latest era. Since most complications after hepatectomy were considered preventable, step-by-step meticulous surgical procedures are a prerequisite for further assuring donor safety irrespective of the type of hepatectomy selected.

MHC universal cells survive in an allogeneic environment after incompatible transplantation

Cell, tissue, and organ transplants are commonly performed for the treatment of different diseases. However, major histocompatibility complex (MHC) diversity often prevents complete donor-recipient matching, resulting in graft rejection. This study evaluates in a preclinical model the capacity of MHC class I-silenced cells to engraft and grow upon allogeneic transplantation. Short hairpin RNA targeting β2-microglobulin (RN_shβ2m) was delivered into fibroblasts derived from LEW/Ztm (RT1^l) (RT1-A^l) rats using a lentiviral-based vector. MHC class I (RT1-A-) expressing and -silenced cells were injected subcutaneously in LEW rats (RT1^l) and MHC-congenic LEW.1W rats (RT1^u), respectively. Cell engraftment and the status of the immune response were monitored for eight weeks after transplantation. In contrast to RT1-A-expressing cells, RT1-A-silenced fibroblasts became engrafted and were still detectable eight weeks after allogeneic transplantation. Plasma levels of proinflammatory cytokines IL-1α, IL-1β, IL-6, TNF-α, and IFN-γ were significantly higher in animals transplanted with RT1-A-expressing cells than in those receiving RT1-A-silenced cells. Furthermore, alloantigen-specific T-cell proliferation rates derived from rats receiving RT1-A-expressing cells were higher than those in rats transplanted with RT1-A-silenced cells. These data suggest that silencing MHC class I expression might overcome the histocompatibility barrier, potentially opening up new avenues in the field of cell transplantation and regenerative medicine.