Post-transplant donor-specific anti-HLA antibodies with a higher mean fluorescence intensity are associated with graft fibrosis in pediatric living donor liver transplantation

The roles of post-transplant anti-HLA donor specific antibody (DSA) in pediatric liver transplantation (LT), including therapeutic strategies, remain controversial. This study aimed to identify the risks of post-transplant DSA for graft fibrosis progression in pediatric living donor LT (LDLT). We retrospectively evaluated 88 LDLT pediatric cases between December 1995 and November 2019. DSAs were assessed with single antigen bead test. Graft fibrosis was histopathologically scored with METAVIR and the centrilobular sinusoidal fibrosis system. Post-transplant DSAs were detected in 37 (52.9%) cases at 10.8 (1.3–26.9) years post-LDLT. The histopathological examination of 32 pediatric cases with post-transplant DSA revealed that 7 (21.9%) with a high DSA-MFI (≥9,378) showed graft fibrosis progression (≥F2). No graft fibrosis was observed in the subjects with a low DSA-MFI. The risk factors for developing graft fibrosis in pediatric cases with post-transplant DSA were an older graft age (>46.5 years old), lower platelet count (<10.7 × 104/ml) and higher Fib4 index (>0.7807, recipient age; >1.8952, donor age). Limited efficacy of additional immunosuppressants was observed in DSA positive pediatric cases. In conclusion, pediatric cases with a high DSA-MFI and risk factors should undergo a histological examination. The appropriate treatment for post-transplant DSA in pediatric LT needs to be determined

The Efficacy of the Hepatocyte Spheroids for Hepatocyte Transplantation

The safety and short-term efficacy of hepatocyte transplantation (HCTx) have been widely proven. However, issues such as reduced viability and/or function of hepatocytes, insufficient engraftment, and lack of a long-term effect have to be overcome for widespread application of HCTx. In this study, we evaluated hepatocyte spheroids (HSs), formed by self-aggregation of hepatocytes, as an alternative to hepatocytes in single-cell suspension. Hepatocytes were isolated from C57BL/6 J mice liver using a three-step collagenase perfusion technique and HSs were formed by the hanging drop method. After the spheroids formation, the HSs showed significantly higher mRNA expression of albumin, ornithine transcarbamylase, glucose-6-phosphate, alpha-1-antitrypsin, low density lipoprotein receptor, coagulation factors, and apolipoprotein E (ApoE) than 2 dimensional (2D)-cultured hepatocytes (p < 0.05). Albumin production by HSs was significantly higher than that by 2D-cultured hepatocytes (9.5 +/- 2.5 vs 3.5 +/- 1.8 mu g/dL, p < 0.05). The HSs, but not single hepatocytes, maintained viability and albumin mRNA expression in suspension (92.0 +/- 2.8% and 1.03 +/- 0.09 at 6 h). HSs (3.6 x 10(6) cells) or isolated hepatocytes (fSH, 3.6 x 10(6) cells) were transplanted into the liver of ApoE knockout (KO-/-) mice via the portal vein. Following transplantation, serum ApoE concentration (ng/mL) of HS-transplanted mice (1w: 63.1 +/- 56.7, 4w: 17.0 +/- 10.9) was higher than that of fSH-transplanted mice (1 w: 33.4 +/- 13.0, 4w: 13.7 +/- 9.6). In both groups, the mRNA levels of pro-inflammatory cytokines (IL-6, IL-1 beta, TNF-alpha, MCP-1, and MIP-1 beta) were upregulated in the liver following transplantation; however, no significant differences were observed. Pathologically, transplanted HSs were observed as flat cell clusters in contact with the portal vein wall on day 7. Additionally, ApoE positive cells were observed in the liver parenchyma distant from the portal vein on day 28. Our results indicate that HS is a promising alternative to single hepatocytes and can be applied for HCTx

Novel immunological approach to asses donor reactivity of transplant recipients using a humanized mouse model

In organ transplantation, a reproducible and robust immune-monitoring assay has not been established to determine individually tailored immunosuppressants (IS). We applied humanized mice reconstituted with human (hu-) peripheral blood mononuclear cells (PBMCs) obtained from living donor liver transplant recipients to evaluate their immune status. Engraftment of 2.5 x 10(6) hu-PBMCs from healthy volunteers and recipients in the NSG mice was achieved successfully. The reconstituted lymphocytes consisted mainly of hu-CD3(+) lymphocytes with predominant CD45RA(-)CD62L(lo) T-EM and CCR6(-)CXCR3(+)CD4(+) Th1 cells in hu-PBMC-NSG mice. Interestingly, T cell allo-reactivity of hu-PBMC-NSG mice was amplified significantly compared with that of freshly isolated PBMCs (p < 0.05). Furthermore, magnified hu-T cell responses to donor antigens (Ag) were observed in 2/10 immunosuppressed recipients with multiple acute rejection (AR) experiences, suggesting that the immunological assay in hu-PBMC-NSG mice revealed hidden risks of allograft rejection by IS. Furthermore, donor Ag-specific hyporesponsiveness was maintained in recipients who had been completely weaned off IS (n = 4), despite homeostatic proliferation of hu-T cells in the hu-PBMC-NSG mice. The immunological assay in humanized mice provides a new tool to assess recipient immunity in the absence of IS and explore the underlying mechanisms to maintaining operational tolerance

The impact of preformed donor-specific antibodies in living donor liver transplantation according to graft volume

Introduction: The roles of preformed anti-HLA donor-specific antibodies (DSAs) in liver transplantation remain controversial. We evaluated the impact of preformed DSAs in living donor liver transplantation. Methods: Adults who underwent living donor liver transplantation (n = 175) in our institute were included in this study. Lymphocyte cytotoxicity test (LCT), flow cytometric crossmatch (FCXM), and single-antigen bead assays were performed. Results: Among adult living donor liver transplantation recipients, 27 (16.5%) and 14 (8.5%) had pretransplant FCXM-positive findings and LCT-positive findings, respectively. FCXM-positive patients displayed a significantly worse 5-year graft survival rate (77.3%; vs. DSA-negative, 91.6%). Six of 14 LCT-positive patients exhibited graft loss shortly after transplantation (5-year survival rate: 57.1%). All LCT-positive patients with graft loss underwent left lobe living donor liver transplantation. Significantly lower ratio of graft volume relative to standard liver volume (32.9 +/- 5.7%) and smaller graft size (365.3 +/- 57.9 g) were observed in patients with graft loss (p<.03, vs. surviving grafts). Significantly higher DSA-mean fluorescence intensity (MFI) values were present in patients with graft loss (p=.0012, vs. surviving grafts). Conclusions: Patients with preformed DSAs exhibited worse graft outcomes in living donor liver transplantation. Higher DSA-MFI values and smaller graft size were associated with worse outcomes in LCT-positive patients. High-risk patients with preformed DSAs should be considered for appropriate graft selection and application of a desensitization protocol

Long‐term risk of a fatty liver in liver donors

Abstract Aim Approximately 30 years have passed since the first experience of living donor liver transplantation. The time to evaluate the long‐term safety of living donors has been fulfilled. Meanwhile, nonalcoholic fatty liver disease is increasingly common and a critical problem. The aim of this study was to evaluate the safety of living donor, focusing on fatty liver postdonation hepatectomy. Methods Living donors (n = 212, 1997–2019) were evaluated by computed tomography (CT) at >1‐year postdonation. A liver to spleen (L/S) ratio of 1.3, which included a case with a Fib‐4 index of >2.67, no significant increased Fib‐4 index was observed in the subjects with fatty liver as compared to those without fatty liver (p = 0.66). The independent predictive risk factors for developing fatty liver were male sex, pediatric recipient, and higher body mass index (>25) at donation. Conclusion Living donors with risk factors for developing fatty liver should be carefully followed‐up for the prevention and management of metabolic syndrome

Solid pseudopapillary neoplasm of the pancreas after living-donor liver transplantation

Background: Solid pseudopapillary neoplasm of the pancreas has been classified by the World Health Organization as a low-grade malignant tumor with potential to metastasize. The standard treatment for this neoplasm is complete surgical resection. However, it is not always feasible to perform a complex procedure such as pancreaticoduodenectomy or distal pancreatectomy, espe-cially for patients with a history of hepato-biliary-pancreatic surgery. In such cases, the treat-ment strategy must consider the patient's postoperative quality of life. We herein report a case of solid pseudopapillary neoplasm of the pancreas following living-donor liver transplantation.Case presentation: The patient was a 13-year-old girl who had undergone the Kasai procedure for biliary atresia at 140 days of age. She thereafter underwent living-donor liver transplanta-tion because of recurrent cholangitis and progressive jaundice. Her repeated history of cholan-gitis had caused narrowing of the portal vein. Therefore, the portal vein was reconstructed us -ing the donor's ovarian vein as an interposition graft. At 13 years of age, a mass was identified at the head of the pancreas. Biopsy was performed and the patient was diagnosed with solid pseudopapillary neoplasm of the pancreas. Surgical resection was planned, and three options were considered: pancreaticoduodenectomy, duodenum-preserving pancreatic head resection, and enucleation. Considering the complications associated with radical surgery, tumor enucle-ation was performed. The patient developed a postoperative pancreatic fistula that required prolonged fasting and drainage. She began a low-fat diet on postoperative day 15. Because the pancreatic fistula was well controlled with a low-fat diet, the patient was discharged on postop-erative day 51 after she and her parents had received dietary guidance. At the time of this writ-ing, 1 year had passed since the enucleation with no evidence of recurrence.Conclusions: We have herein reported a case of solid pseudopapillary neoplasm of the pancreas after living-donor liver transplantation. Although a radical operation such as pancreaticoduo- denectomy or distal pancreatectomy is preferable from an oncological perspective, enucleation should be considered for patients with high surgical risk