Interleukin-33 and liver natural killer cells: A novel perspective on antitumor activity in liver fibrosis.

AIM: Liver fibrosis, heralding the potential progression to cirrhosis and hepatocellular carcinoma (HCC), compromises patient survival and augments post-hepatectomy recurrence. This study examined the detrimental effects of liver fibrosis on the antitumor functions of liver natural killer (NK) cells and the interleukin-33 (IL-33) signaling pathway. METHODS: Our investigation, anchored in both human physiologies using living and deceased donor livers and the carbon tetrachloride (CCl4)-induced mouse fibrosis model, aimed to show a troubling interface between liver fibrosis and weakened hepatic immunity. RESULTS: The Fibrosis-4 (FIB-4) index emerged as a salient, non-invasive prognostic marker, and its elevation correlated with reduced survival and heightened recurrence after HCC surgery even after propensity matching (n = 385). We established a strong correlation between liver fibrosis and liver NK cell dysfunction by developing a method for extracting liver NK cells from the liver graft perfusate. Furthermore, liver fibrosis ostensibly disrupted chemokines and promoted IL-33 expression, impeding liver NK cell antitumor activities, as evidenced in mouse models. Intriguingly, our results implicated IL-33 in diminishing the antitumor responses of NK cells. This interrelation, consistent across both mouse and human studies, coincides with clinical data suggesting that liver fibrosis predisposes patients to an increased risk of HCC recurrence. CONCLUSION: Our study revealed a critical relationship between liver fibrosis and compromised tumor immunity, emphasizing the potential interference of IL-33 with NK cell function. These insights advocate for advanced immunostimulatory therapies targeting cytokines, such as IL-33, aiming to bolster the hepatic immune response against HCC in the context of liver fibrosis.

Cell competition is driven by Xrp1-mediated phosphorylation of eukaryotic initiation factor 2α.

Cell competition is a context-dependent cell elimination via cell-cell interaction whereby unfit cells ('losers') are eliminated from the tissue when confronted with fitter cells ('winners'). Despite extensive studies, the mechanism that drives loser's death and its physiological triggers remained elusive. Here, through a genetic screen in Drosophila, we find that endoplasmic reticulum (ER) stress causes cell competition. Mechanistically, ER stress upregulates the bZIP transcription factor Xrp1, which promotes phosphorylation of the eukaryotic translation initiation factor eIF2α via the kinase PERK, leading to cell elimination. Surprisingly, our genetic data show that different cell competition triggers such as ribosomal protein mutations or RNA helicase Hel25E mutations converge on upregulation of Xrp1, which leads to phosphorylation of eIF2α and thus causes reduction in global protein synthesis and apoptosis when confronted with wild-type cells. These findings not only uncover a core pathway of cell competition but also open the way to understanding the physiological triggers of cell competition.

[Well Differentiated Liposarcoma of a Lung:Report of a Case].

A 61-year-old woman was referred for further evaluation of an intracystic nodule in her left upper lung. Computed tomography( CT) showed a 15 mm nodule in a pulmonary cyst adjacent to aortic arch and mediastinum. Fluorodeoxyglucose-positron emission tomography (FDG-PET)-CT showed little uptake of FDG in the lesion. No abnormality was found in the bronchoscopy findings. On imaging findings, the possibility of pulmonary aspergilloma was considered, but the serological findings were inconsistent, and surgical resection of the lesion was performed for both diagnosis and treatment. The final pathohistological diagnosis was well differentiated liposarcoma. No adjuvant therapy was performed and the patient has been well without recurrence for 2 years after the surgery. We report a rare case of well differentiated liposarcoma of a lung mimicking pulmonary aspergilloma.

Surgery-related disseminated intravascular coagulation predicts postoperative complications.

PURPOSE: The rate of postoperative morbidity, including infectious complications, is still high after major hepatobiliary pancreatic (HBP) surgery. Although surgery-related disseminated intravascular coagulation (DIC) occurs in some cases, its significance has not been elucidated in HBP surgery. This study aimed to evaluate the influence of surgery-related DIC on the complication severity after HBP surgery. METHODS: We analyzed the records of 100 patients with hepatectomy in two or more segments, hepatectomy with biliary tract reconstruction, and pancreaticoduodenectomy. The baseline characteristics and complications were compared between patients with and without surgery-related DIC on postoperative day 1 (POD1) after HBP surgery between 2010 and 2018. Complication severity was assessed using the Comprehensive Complication Index (CCI). RESULTS: The DIC group (surgery-related DIC on POD1) had predictive factors, such as larger bleeding volume and higher liver enzyme levels. The DIC group exhibited significantly elevated rates of surgical site infection, sepsis, prolonged intensive care unit stay, more frequent blood transfusions, and higher CCI. Furthermore, compared with and without adjustment of DIC, odds ratio (OR) of AST level and operation time for  the risk of high CCI decreased (OR of AST level: 1.25 to 1.19 and OR of operation time: 1.30 to 1.23) and the significant differences had vanished. CONCLUSIONS: Surgery-related DIC on POD1 could be a partial mediator between AST level, operation time and higher CCI. The prevention or proper management of surgery-related DIC on POD1 can be an important target to reduce the severity of postoperative complications.

Adoptive immunotherapy overcomes genetic susceptibility to bloodstream infections due to fc-gamma receptor polymorphisms after liver transplantation.

Single nucleotide polymorphisms (SNPs) in FCGR3A can predict the susceptibility of liver transplant (LT) recipients to bloodstream infections (BSI) and clinical outcomes following living-donor LT (LDLT). Here, we retrospectively analyzed the relationship of adoptive immunotherapy with activated natural killer (NK) cells from perfusate effluents of liver allografts against BSI following LDLT. Higher BSI incidence and lower survival were observed in LT recipients with FcγRIIIa (158F/F or F/V) (n = 81) who did not receive adoptive immunotherapy (n = 55) than in those who did (n = 26) (BSI frequency, 36.4% vs. 11.5%; p = .033; log-rank p = .047). After matching patient background using propensity score, similar results were obtained (BSI ratio, 41.7% vs. 12.5%; p = .049; log-rank p = .039). The predominant BSI pathogens in patients who did and did not receive adoptive immunotherapy were gram-negative rods (n = 3, 100%) and gram-positive cocci (GPC) (n = 15, 65.2%), respectively. The proportion of NK cells administered to patients with BSI was significantly lower than that administered to patients without BSI (Number: 80.3 (29.9-239.2) × 106 cells vs. 37.1 (35.6-50.4) × 106 ; p = .033, percentage; 14.1 (13.3-17.8)% vs. 34.6 (16.5-47)%, p = .0078). Therefore, adoptive immunotherapy with NK cells was associated with the reduced post-transplant BSI related to GPCs due to FcγRIIIa SNP in LT recipients.

Donor plasmacytoid dendritic cells modulate effector and regulatory T cell responses in mouse spontaneous liver transplant tolerance.

We assessed the role of donor liver non-conventional plasmacytoid dendritic cells (pDCs) in spontaneous liver transplant tolerance in a fully MHC-mismatched (C57BL/6 (H2b ) to C3H (H2k )) mouse model. Compared with spleen pDCs, liver pDCs expressed higher levels of DNAX-activating protein of 12 kDa and its co-receptor, triggering receptor expressed by myeloid cells 2, and higher ratios of programed death ligand-1 (PD-L1):costimulatory CD80/CD86 in the steady state and after Toll-like receptor 9 ligation. Moreover, liver pDCs potently suppressed allogeneic CD4+ and CD8+ T cell proliferative responses. Survival of pDC-depleted livers was much poorer (median survival time: 25 days) than that of either untreated donor livers or pDC-depleted syngeneic donor livers that survived indefinitely. Numbers of forkhead box p3 (FoxP3)+ regulatory T cells in grafts and mesenteric lymph nodes of mice given pDC-depleted allogeneic livers were reduced significantly compared with those in recipients of untreated livers. Graft-infiltrating CD8+ T cells with an exhausted phenotype (programed cell death protein 1+ , T cell immunoglobulin and mucin domain-containing protein 3+ ) were also reduced in recipients of pDC-depleted livers. PD1-PD-L1 pathway blockade reversed the reduction in exhausted T cells. These novel observations link immunoregulatory functions of liver interstitial pDCs, alloreactive T cell exhaustion, and spontaneous liver transplant tolerance.

State-Targeting Stabilization of Adenosine A2A Receptor by Fusing a Custom-Made De Novo Designed α-Helical Protein.

G-protein coupled receptors (GPCRs) are known for their low stability and large conformational changes upon transitions between multiple states. A widely used method for stabilizing these receptors is to make chimeric receptors by fusing soluble proteins (i.e., fusion partner proteins) into the intracellular loop 3 (ICL3) connecting the transmembrane helices 5 and 6 (TM5 and TM6). However, this fusion approach requires experimental trial and error to identify appropriate soluble proteins, residue positions, and linker lengths for making the fusion. Moreover, this approach has not provided state-targeting stabilization of GPCRs. Here, to rationally stabilize a class A GPCR, adenosine A2A receptor (A2AR) in a target state, we carried out the custom-made de novo design of α-helical fusion partner proteins, which can fix the conformation of TM5 and TM6 to that in an inactive state of A2AR through straight helical connections without any kinks or intervening loops. The chimeric A2AR fused with one of the designs (FiX1) exhibited increased thermal stability. Moreover, compared with the wild type, the binding affinity of the chimera against the agonist NECA was significantly decreased, whereas that against the inverse agonist ZM241385 was similar, indicating that the inactive state was selectively stabilized. Our strategy contributes to the rational state-targeting stabilization of GPCRs.

Cortex glia clear dead young neurons via Drpr/dCed-6/Shark and Crk/Mbc/dCed-12 signaling pathways in the developing Drosophila optic lobe.

The molecular and cellular mechanism for clearance of dead neurons was explored in the developing Drosophila optic lobe. During development of the optic lobe, many neural cells die through apoptosis, and corpses are immediately removed in the early pupal stage. Most of the cells that die in the optic lobe are young neurons that have not extended neurites. In this study, we showed that clearance was carried out by cortex glia via a phagocytosis receptor, Draper (Drpr). drpr expression in cortex glia from the second instar larval to early pupal stages was required and sufficient for clearance. Drpr that was expressed in other subtypes of glia did not mediate clearance. Shark and Ced-6 mediated clearance of Drpr. The Crk/Mbc/dCed-12 pathway was partially involved in clearance, but the role was minor. Suppression of the function of Pretaporter, CaBP1 and phosphatidylserine delayed clearance, suggesting a possibility for these molecules to function as Drpr ligands in the developing optic lobe.

DNAX Activating Protein of 12 kDa/Triggering Receptor Expressed on Myeloid Cells 2 Expression by Mouse and Human Liver Dendritic Cells: Functional Implications and Regulation of Liver Ischemia-Reperfusion Injury.

Liver interstitial dendritic cells (DCs) have been implicated in the control of ischemia-reperfusion injury (IRI) and host immune responses following liver transplantation. Mechanisms underlying these regulatory functions of hepatic DCs remain unclear. We have shown recently that the transmembrane immunoadaptor DNAX-activating protein of 12 kDa (DAP12) negatively regulates mouse liver DC maturation and proinflammatory and immune stimulatory functions. Here, we used PCR analysis and flow cytometry to characterize expression of DAP12 and its associated triggering receptor, triggering receptor expressed on myeloid cells 2 (TREM2), by mouse and human liver DCs and other immune cells compared with DCs in other tissues. We also examined the roles of DAP12 and TREM2 and their expression by liver DCs in the regulation of liver IRI. Injury was induced in DAP12-/- , TREM2-/- , or wild-type (WT) mice by 1 hour of 70% clamping and quantified following 6 hours of reperfusion. Both DAP12 and TREM2 were coexpressed at comparatively high levels by liver DCs. Mouse liver DCs lacking DAP12 or TREM2 displayed enhanced levels of nuclear factor κB and costimulatory molecule expression. Unlike normal WT liver DCs, DAP12-/- liver DC failed to inhibit proliferative responses of activated T cells. In vivo, DAP12-/- and TREM2-/- mice exhibited enhanced IRI accompanied by augmented liver DC activation. Elevated alanine aminotransferase levels and tissue injury were markedly reduced by infusion of WT but not DAP12-/- DC. Conclusion: Our data reveal a close association between DAP12 and TREM2 expression by liver DC and suggest that, by negatively regulating liver DC stimulatory function, DAP12 promotes their control of hepatic inflammatory responses; the DAP12/TREM2 signaling complex may represent a therapeutic target for control of acute liver injury/liver inflammatory disorders.

Impact of Abdominal Aortic Calcification Among Liver Transplantation Recipients.

Abdominal aortic calcification (AAC) is known as a risk factor of coronary artery disease, stroke, hyperphosphatemia, chronic inflammation, diabetes, and decreased estimated glomerular filtration rate. However, the clinical implications of incidental AAC findings in liver transplantation (LT) have not been evaluated in terms of posttransplantation survival and complications. Therefore, we analyzed the relationships between the AAC level and the outcomes following LT. A total of 156 consecutive patients who underwent LT between January 2007 and December 2014 were divided into 2 groups according to their AAC level (<100 mm3 or ≥100 mm3 ), as calculated using the Agatston method. Even after propensity matching, the survival time was significantly longer in the low-AAC group compared with that in the high-AAC group (median survival time, 4.5 versus 3.0 years; P < 0.01). A multivariate analysis identified high AAC level (hazard ratio, 2.2) and old donor age (hazard ratio, 2.2) as prognostic factors for overall survival. In conclusion, high AAC is an independent unfavorable prognostic factor in LT.

Metabolism of steroids by cytochrome P450 2C9 variants.

CYP2C9 is a human microsomal cytochrome P450c (CYP). Much variation in CYP2C9 levels and activity can be attributed to polymorphisms of this gene. Wild-type CYP2C9 and ten mutants were co-expressed with NADPH-cytochrome P450 reductase in Escherichia coli. The hydroxylase activities toward steroids were examined. CYP2C9.2, CYP2C9.3, CYP2C9.4, CYP2C9.16, CYP2C9.28, CYP2C9.48 and CYP2C9.52 had higher testosterone 6ß-hydroxylation than CYP2C9.1. CYP2C9.4 showed higher progesterone 6ß-hydroxylation activity than CYP2C9.1. CYP2C9.28 and CYP2C9.48 showed higher progesterone 11α-hydroxylation activity than CYP2C9.1. CYP2C9.48 showed higher progesterone 16α-hydroxylation activity than CYP2C9.1. CYP2C9.2, CYP2C9.3, CYP2C9.16 and CYP2C9.30 had higher estrone 16α-hydroxylation activity than CYP2C9.1. CYP2C9.3 had higher estrone 11α-hydroxylation activity than CYP2C9.1. CYP2C9.39 and CYP2C9.57 showed similar activities to CYP2C9.1. These results indicate that the substrate specificity of CYP2C9.39 and CYP2C9.57 was not changed, but CYP2C9.2, CYP2C9.3, CYP2C9.4, CYP2C9.16, CYP2C9.28, CYP2C9.30, CYP2C9.48 and CYP2C9.52 showed different hydroxylation activities toward steroids compared with CYP2C9.1.

Metabolism of 7-ethoxycoumarin, flavanone and steroids by cytochrome P450 2C9 variants.

CYP2C9 is a human microsomal cytochrome P450c (CYP). Much of the variation in CYP2C9 levels and activity can be attributed to polymorphisms of this gene. Wild-type CYP2C9 and mutants were coexpressed with NADPH-cytochrome P450 reductase in Escherichia coli. The hydroxylase activities toward 7-ethoxycoumarin, flavanone and steroids were examined. Six CYP2C9 variants showed Soret peaks (450 nm) typical of P450 in reduced CO-difference spectra. CYP2C9.38 had the highest 7-ethoxycoumarin de-ethylase activity. All the CYP2C9 variants showed lower flavanone 6-hydroxylation activities than CYP2C9.1 (the wild-type). CYP2C9.38 showed higher activities in testosterone 6ß-hydroxylation, progesterone 6ß-/16α-hydroxylation, estrone 11α-hydroxylation and estradiol 6α-hydroxylation than CYP2C9.1. CYP2C9.40 showed higher testosterone 17-oxidase activity than CYP2C9.1; CYP2C9.8 showed higher estrone 16α-hydroxylase activity and CYP2C9.12 showed higher estrone 11α-hydroxylase activity. CYP2C9.9 and CYP2C9.10 showed similar activities to CYP2C9.1. These results indicate that the substrate specificity of CYP2C9.9 and CYP2C9.10 was not changed, but CYP2C9.8, CYP2C9.12 and CYP2C9.40 showed different substrate specificity toward steroids compared with CYP2C9.1; and especially CYP2C9.38 displayed diverse substrate specificities towards 7-ethoxycoumarin and steroids.

[A Case of Locally Advanced Pancreatic Cancer Showing R0 Resection after Resection of the Portal Vein Following Preoperative Chemoradiotherapy].

We report a case of pancreatic cancer showing R0 resection after resection of the portal vein(PV)following preoperative chemoradiotherapy. A 71-year-old woman was admitted to our hospital with back pain. We diagnosed the patient with pancreatic cancer using computed tomography scan and fine-needle aspiration biopsy. Because the tumor directly invaded the PV, we diagnosed it as a borderline resectable locally advanced pancreatic cancer. Radiation therapy(40 Gy/20 Fr)was administered with S-1 monotherapy(120 mg/body/day on days 1-5 and days 8-12). After the treatment, the main tumor was stable without distant metastasis. Therefore, we performed pancreaticoduodenectomy with resection of the PV. Pathological examination confirmed negative margin status. The patient was healthy and showed no sign of recurrence eight months after surgery.

Treatment of hepatic amyloid light-chain amyloidosis with bortezomib and dexamethasone in a liver transplant patient.

Hepatic amyloid light-chain (AL) amyloidosis is characterized by abnormal deposition of amyloid fibrils in the liver. As this precursor protein is produced by a proliferative plasma cell clone in the bone marrow, liver transplantation (LT) does not affect the disease's progression. Here, we describe the successful treatment using bortezomib- and dexamethasone-based chemotherapy, following LT, of hepatic AL amyloidosis in a 65-year-old woman with progressive liver failure. The patient presented with progressive hepatic dysfunction accompanied by hepatorenal syndrome requiring hemodialysis, and living donor LT was successfully performed. Histology revealed amyloid deposits in the liver and stomach, and serum immunofixation revealed AL amyloidosis (κ-type). The patient began chemotherapy on day 45 after the LT, and remission was achieved after one course. She was subsequently discharged 83 days after the LT, with normal liver and renal function, and no clinical evidence of recurrent disease was observed at the latest follow up (22 months post-LT).

[A case of lung cancer with small intestine metastasis with perforative peritonitis as the initial symptom].

Herein, we report a case oflung cancer with metastasis to the small intestine, with perforative peritonitis as the initial symptom. An 82-year-old man who had undergone subtotal gastrectomy and Roux-en-Y anastomosis for gastric cancer 8 years previously was admitted to our hospital with abdominal pain. We diagnosed the patient with gastrointestinal perforation, and a chest computed tomography(CT)scan showed a mass in the right lung. A laparotomy revealed a 4×3 cm sized intestinal tumor and intestinal perforation in the immediate vicinity ofthe anastomotic site. Segmentectomy ofthe small intestine was performed. Histological examination indicated that the tumor specimen was squamous cell carcinoma. Four months later, an abdominal CT scan showed multiple liver metastases, and the patient died 6 months after the operation because ofcachexia. At autopsy, a diagnosis ofsmall intestine metastatic tumor originating from squamous cell carcinoma of the lung was made. Although small intestine metastasis from lung cancer is rare, it should be considered when progressive abdominal symptoms are observed.

Association of Abdominal Aortic Calcification With the Postoperative Metabolic Syndrome Components After Liver Transplantation.

BACKGROUND: This study aimed to assess the risk factors for components of metabolic syndrome, such as diabetes mellitus, hypertension, and dyslipidemia, more than a year after liver transplantation. METHODS: This study included 164 patients with liver failure secondary to acute and chronic liver disease or hepatocellular carcinoma who underwent liver transplantation between 2000 and 2019. Univariate and multivariate analyses were performed to identify the risk factors associated with metabolic syndrome components after liver transplantation. RESULTS: The median follow-up period was 10.5 years. Of the 164 patients who underwent liver transplantation, 144 (87.8%) developed components of metabolic syndrome after liver transplantation. The most common cause of liver failure was hepatitis C virus infection (34.1%). The incidence of hepatocellular carcinoma was 36.0%. In univariate analysis, preoperative diabetes mellitus was a significantly more common component of metabolic syndrome than the others. In multivariate analysis, preoperative abdominal aortic calcification was a risk factor for the new onset of all components of metabolic syndrome after liver transplantation, despite the varying degree of calcification at risk of development (odds ratio for diabetes mellitus = 3.487, P = .0069; odds ratio for hypertension = 2.914, P = .0471; odds ratio for dyslipidemia = 3.553, P = .0030). CONCLUSIONS: Preoperative abdominal aortic calcification was significantly associated with the development of each metabolic syndrome component after liver transplantation.

Atherosclerosis Deteriorates Liver Ischemia/Reperfusion Injury Via Interferon Regulatory Factor-1 Overexpression in a Murine Model.

BACKGROUND: Abdominal aortic calcification (AAC) is associated with cardiovascular-related mortality, along with an elevated risk of coronary, cerebrovascular, and cardiovascular events. Notably, AAC is strongly associated with poor overall and recurrence free survival posthepatectomy for hepatocellular carcinoma. Despite the acknowledged significance of atherosclerosis in systemic inflammation, its response to ischemia/reperfusion injury (IRI) remains poorly elucidated. In this study, we aimed to clarify the impact of atherosclerosis on the liver immune system using a warm IRI mouse model. METHODS: Injury was induced in an atherosclerotic mouse model (ApoE-/-) or C57BL/6J wild-type (WT) mice through 70% clamping for 1 hour and analyzed after 6 hours of reperfusion. RESULTS: Elevated serum levels of aspartate and alanine aminotransferase, along with histological assessment, indicated considerable damage in the livers of ApoE-/- mice than that in WT mice. This indicates a substantial contribution of atherosclerosis to IRI. Furthermore, T and natural killer (NK) cells in ApoE-/- mouse livers displayed a more inflammatory phenotype than those in WT mouse livers. Reverse transcription-polymerase chain reaction analysis revealed a significant upregulation of interleukin (IL)-15 and its transcriptional regulator, interferon regulatory factor-1 (IRF-1) in ApoE-/- mouse livers compared with that in WT mouse livers. CONCLUSIONS: These findings suggest that in an atherosclerotic mouse model, atherosclerosis can mirror intrahepatic immunity, particularly activating liver NK and T cells through IL-15 production, thereby exacerbating hepatic damage. The upregulation of IL-15 expression is associated with IRF-1 overexpression.

Polymorphisms in genes involved in regulating follicular helper T cell differentiation predict de novo donor-specific antibody formation after liver transplantation.

BACKGROUND: De novo donor-specific antibodies (dnDSAs) significantly affect the long-term outcomes of liver transplantation (LT), highlighting the importance of risk prediction. Follicular helper T (Tfh) cells have been implicated in dnDSA formation after transplantation. Considering the influence of immune response gene polymorphisms on transplantation outcomes, we investigated the association between polymorphisms in Tfh cell-related genes and dnDSA formation after LT. METHODS: Fifty-three living-donor LT patients were included in this study. Single nucleotide polymorphisms (SNPs) were identified in six Tfh cell-related genes crucial for differentiation and maturation (BCL6, CXCR5, CXCL13, ICOS, CD40L, and IL-21); their association with the development of dnDSA after LT was evaluated. RESULTS: Among the 53 recipients, 9 developed dnDSAs. BCL6 and IL-21 SNPs showed potential associations with dnDSA formation, enabling risk stratification. CONCLUSIONS: Variations in Tfh cell-related genes may predispose individuals to dnDSA formation after LT, emphasizing the importance of genetic factors for predicting post-transplant complications.

Impact of KIR-HLA Genotype on Natural-Killer-Cell-Based Immunotherapy for Preventing Hepatocellular Carcinoma after Living-Donor Liver Transplantation.

Natural killer (NK) cells have immunosurveillance potential in hepatocellular carcinoma (HCC). We performed adaptive immunotherapy using donor-liver-derived natural killer (NK) cells after living-donor liver transplantation (LDLT) to prevent HCC recurrence. Dominant inhibitory signals tightly regulate NK cell activity via human leukocyte antigen (HLA)-specific inhibitory receptors, such as killer immunoglobulin-like receptors (KIRs). The functional recognition of HLA through KIR raises the NK cell capacity, which is a process termed "licensing." Here, we investigated the effect of polymorphic KIR-HLA genotypes on the efficacy of NK-cell-based immunotherapy after LDLT. Seventy-seven Japanese recipients with HCC who underwent LDLT and their corresponding donors between 1996 and 2016 were enrolled in this study. The median follow-up period was 8.3 years. The HCC recurrence risk was stratified using radiological and pathological assessments according to the Milan criteria. Of the 77 recipients, 38 received immunotherapy. Immunotherapy improves early post-transplantation survival and lowers the recurrence rate in the intermediate-risk recipients. We analyzed the genotypes of five inhibitory KIRs and HLA using sequence-specific polymorphism-based typing. The polymorphic KIR-HLA genotype revealed that genetically vulnerable liver transplant recipients with a poorly licensed NK genotype have an improved prognosis by immunotherapy with donor-liver-derived NK cells. Thus, the combination of recipient and donor KIR-HLA genotypes is worthy of attention for further investigation, especially considering the clinical application of NK-cell-based immunotherapy.