Published papers

Background: The Model for End-Stage Liver Disease 3.0 (MELD 3.0) was developed in the United States to improve prioritization for liver transplantation (LT); however, its utility in Japanese patients with liver cirrhosis (LC) and acute decompensation (AD) remains invalidated. Methods: We retrospectively analyzed 312 patients with LC and first-time AD admitted to our institution between 2012 and 2022. Prognostic accuracy of MELD 3.0 was evaluated at 90 and 180 days after admission by comparison with other predictive models. Prognoses according to cirrhosis etiology and contributing factors were also examined. Results: MELD 3.0 demonstrated superior prognostic accuracy at day 180 (C-index: 0.770) compared to the original MELD and MELD Na, although its C-index up to day 90 was comparable to that of MELD and MELD Na. A cut-off value of MELD 3.0 > 20.5 predicted LT or liver-related death at day 180. Patients with primary biliary cholangitis (PBC) had poorer outcomes than non-PBC cases through 180 days and remained an independent risk factor in the Cox proportional hazards model incorporating MELD 3.0. A progressive increase in both MELD 3.0 and total bilirubin from day 0 to day 90 after AD was observed specifically in the PBC group, which may have been associated with the poor prognosis at day 180. Conclusions: MELD 3.0 was effective in predicting 180-day outcomes in Japanese patients with LC and AD. Progressive bilirubin elevation in PBC may be associated with poor prognosis. These findings suggest that early consideration of LT is warranted in patients with PBC.

Primary sclerosing cholangitis (PSC) is a chronic inflammatory liver disease and its frequent complication with ulcerative colitis highlights the pathogenic role of epithelial barrier dysfunction. Intestinal barrier dysfunction has been implicated in the pathogenesis of PSC, yet its underlying mechanism remains unknown. Here, we identify Klebsiella pneumonia in the microbiota of patients with PSC and demonstrate that K. pneumoniae disrupts the epithelial barrier to initiate bacterial translocation and liver inflammatory responses. Gnotobiotic mice inoculated with PSC-derived microbiota exhibited T helper 17 (TH17) cell responses in the liver and increased susceptibility to hepatobiliary injuries. Bacterial culture of mesenteric lymph nodes in these mice isolated K. pneumoniae, Proteus mirabilis and Enterococcus gallinarum, which were prevalently detected in patients with PSC. A bacterial-organoid co-culture system visualized the epithelial-damaging effect of PSC-derived K. pneumoniae that was associated with bacterial translocation and susceptibility to TH17-mediated hepatobiliary injuries. We also show that antibiotic treatment ameliorated the TH17 immune response induced by PSC-derived microbiota. These results highlight the role of pathobionts in intestinal barrier dysfunction and liver inflammation, providing insights into therapeutic strategies for PSC.

The gut-liver axis is of clinical importance as a potential therapeutic target in a wide range of liver diseases; however, the mechanisms underlying interactions between microbial products and immune responses in the liver remain unknown. In this study, we demonstrated that IL-10-producing macrophages contribute to immune tolerance in the inflamed liver under intestinal barrier disruption in a murine tandem model of dextran sulfate sodium (DSS) colitis and concanavalin A (Con A) hepatitis. Intestinal barrier disruption protected mice from subsequent liver injury, and the severity of colitis directly affected susceptibility to such injury. The protective effect of DSS-Con A was canceled in gut-sterilized mice, suggesting that gut microbiota play a substantial role in this process. Altered gut microbiota and their metabolites, along with a disrupted intestinal barrier, directly gave rise to immunological permissiveness in the inflamed liver. We identified 1-methylnicotinamide (1-MNA) as a candidate metabolite capable of suppressing liver injury with the potential to induce IL-10-producing macrophages. Consistently, expression of nicotinamide N-methyltransferase, which converts nicotinamide to 1-MNA, was upregulated in the liver of DSS-Con A mice, and this effect was abrogated by gut sterilization. Collectively, our results provide a mechanistic insight into the regulation of immunological balance in the liver via the gut-liver axis.

Acute liver failure (ALF) is a life-threatening condition, and liver transplantation is the only therapeutic option. Although immune dysregulation is central to its pathogenesis, the precise mechanism remains unclear. Here, we show that the number of peripheral and hepatic plasmacytoid DCs (pDCs) decrease during acute liver injury in both humans and mice. Selective depletion of pDCs in Siglechdtr/+ mice exacerbated concanavalin A-induced acute liver injury. In contrast, adoptively transferred BM-derived pDCs preferentially accumulated in the inflamed liver and protected against liver injury. This protective effect was independent of TLR7 and TLR9 signaling, since a similar effect occurred following transfer of MyD88-deficient pDCs. Alternatively, we found an unexpected immunosuppressive role of pDCs in an IL-35-dependent manner. Both Il12a and Ebi3, heterodimeric components of IL-35, were highly expressed in transferred pDCs and CD4+CD25+ Tregs. However, the protective effect of pDC transfer was completely lost in mice depleted of Tregs by anti-CD25 antibody. Moreover, pDCs derived from IL-35-deficient mice had less of a protective effect both in vivo and in vitro even in the presence of Tregs. These results highlight a unique aspect of pDCs in association with Tregs, serving as a guide for immunotherapeutic options in ALF.

BACKGROUND: Genetic polymorphisms of alcohol dehydrogenase-1B (ADH1B; rs1229984, His48Arg) and aldehyde dehydrogenase-2 (ALDH2; rs671, Glu504Lys) affect body weight, body fat, and lipid metabolism in individuals with alcohol dependence, and the aim of this study was to identify their determinants in relation to the development of fatty liver. METHODS: We evaluated associations between the presence of fatty liver and ADH1B and ALDH2 genotypes and other factors in 1604 Japanese men who had been admitted for treatment of alcohol dependence. RESULTS: Fatty liver was diagnosed when ultrasonography showed both hepatorenal contrast and liver brightness. Age-adjusted usual alcohol intake did not differ according to ADH1B or ALDH2 genotypes. A multivariate analysis showed that the adjusted odds ratio (OR, 95% confidence interval) of slow-metabolizing ADH1B Arg/Arg carriers was 1.61 (1.27-2.03) for fatty liver and 1.82 (1.37-2.41) for fatty liver with deep attenuation in comparison with the ADH1B His/Arg or His/His carriers, and that the OR of inactive heterozygous ALDH2 Glu/Lys carriers was 1.43 (1.08-1.91) for fatty liver and 1.84 (1.31-2.59) for fatty liver with deep attenuation in comparison with the ALDH2 Glu/Glu carriers. Younger age, shorter interval between the last drink and the ultrasound examination, larger body mass index, and absence of cirrhosis were identified as other positive determinants for fatty liver. CONCLUSIONS: The ADH1B Arg/Arg genotype and the ALDH2 Glu/Lys genotype were positive determinants of fatty liver in the subjects. These results suggest that slow ethanol and acetaldehyde metabolism accelerates the development of alcoholic fatty liver in heavy drinkers.

Late-onset acute liver failure due to Wilson's disease (WD-ALF) is rare. A 44-year-old female patient presenting acute hepatic decompensation with extreme coagulopathy was transferred to our hospital for evaluation for liver transplantation (LT). Alveolar hemorrhage and Coombs-negative acute hemolysis occurred during workup. Mechanical ventilation, plasmapheresis, and hemodiafiltration with zinc and chelation were started immediately before placing the patient on the waitlist for deceased donor LT (DDLT), with a tentative diagnosis of WD-ALF using the Leipzig score and quick diagnostic criteria suggested by the Acute Liver Failure Study Group Registry. The peak MELD score was 40, and the revised version of King's score for WD was 13. Serum free copper levels and the patient's overall general condition were stabilized with artificial support systems, although triphasic wave on electroencephalogram and liver atrophy were noted. She successfully underwent emergent DDLT approximately 2 weeks after suffering from acute hemolysis and survived. The genetic tests confirmed mutations at 2 loci in the ATP7B gene and, therefore, the diagnosis of WD. This is the first and oldest patient reported in Japan to present late-onset WD-ALF that was successfully treated with emergent DDLT.

BACKGROUND: Moderate alcohol consumption is believed to be associated with reduced mortality from cardiovascular disease (CVD) in the general population. This cross-sectional study aimed to comprehensively examine the association between alcohol consumption and subclinical cardiovascular damage or hepatic fibrosis in non-alcoholic fatty liver disease (NAFLD). METHODS: Subjects with NAFLD without a history of heart disease were extracted from 977 consecutive examinees who completed health checkups and optional cardiovascular examinations. Subclinical cardiovascular damage was assessed by coronary artery calcification (CAC), carotid artery ultrasound, and brachial-ankle pulse wave velocity (ba-PWV). CAC scores were classified into three grades (0, 100) by Agatston's method. Alcohol consumption was divided into three groups [Non-drinking (G0); Light (G1), 0.1-6.9 drinks/week; Moderate (G2), 7-20.9 drinks/week for men and 7-13.9 drinks/week for women]. Noninvasive markers (FIB-4, Fibrosis-4; NFS, NAFLD fibrosis score) were calculated for assessment of hepatic fibrosis and classified into low and intermediate-high grade. RESULTS: The overall mean age was 60.2 years and males were 200 (74.6%) among 268 subjects with NAFLD. Number (%) of G0, G1, and G2 were 102 (38.1%), 103 (38.4%), and 63 (23.5%). Binary logistic regression analysis showed no significant difference between G0 and G1, or G0 and G2 in any of the above subclinical cardiovascular damages (CAC score >0, or CAC score >100, carotid plaque +, intima-media thickness >/=1.1 mm, and ba-PWV >1400 cm/s). However, only G2 had a significant association with intermediate-high grade of FIB-4 or NFS [odds ratio (95% confidence intervals), p value: 1.871 (1.209-2.893), p = 0.005; 2.910 (1.715-4.939), p = 0.000], compared to G0. CONCLUSIONS: Non-heavy drinking might not reduce the risk of CVD in NAFLD subjects. On the contrary, even moderate drinking could promote hepatic fibrosis. Thus, NAFLD drinkers should not be recommended for even a moderate amount of alcohol.

The gut-brain axis, a reciprocal interaction between the central nervous system (CNS) and peripheral intestinal functions, is conceptually feasible from recent clinical and experimental evidence showing mutual interactions between the CNS and gut microbiota that are closely associated with the bidirectional effects of inflammatory bowel diseases (IBDs) and CNS disorders(1-4). Despite recent advances in our understanding of neuroimmune interactions, it remains unclear how the gut and brain communicate to maintain gut immune homeostasis, including induction and maintenance of peripheral regulatory T cells (pTreg cells) and what environmental cues prompt the host to protect host from development of IBDs. Here, we report a novel liver-brain-gut neural arc that ensures proper differentiation and maintenance of pTreg cells in the gut. The hepatic vagal sensory afferents were responsible for indirectly sensing the gut microenvironment and relaying the sensory inputs to the nucleus tractus solitarius of the brainstem, and ultimately to the vagal parasympathetic nerves and enteric neurons. Surgical and chemical perturbation of the vagal sensory afferents at the hepatic afferent level significantly impaired colonic pTreg cells, which was attributed to impairment of aldehyde dehydrogenase (ALDH) expression and retinoic acid (RA) synthesis by intestinal antigen-presenting cells (APCs). Muscarinic Ach receptor (mAChR) activation directly induced ALDH gene expression both in human and mouse colonic APCs, whereas genetic ablation of mAChRs abolished APC excitement in vitro. Disruption of left vagal sensory afferents from the liver to the brainstem in colitis models reduced the colonic pTreg pool, resulting in increased susceptibility to colitis. These results demonstrate that the novel vago-vagal liver-brain-gut reflex arc tunes the number of pTreg cells and maintains the gut homeostasis. Intervening in this autonomic feedback feed-forward system could help develop new therapeutic strategies to treat or prevent immunological disorders of the gut.

Severe acute-onset autoimmune hepatitis (SA-AIH), a possible cause of acute liver failure (ALF), poses great challenges in diagnosis and management. Latest guidelines and expert reviews advocate a trial of corticosteroids (CS) followed by assessments of their clinical effect for 1-2 weeks with consideration for liver transplantation (LT).

Group 2 innate lymphoid cells (ILC2s) serve as frontline defenses against parasites. However, excluding helminth infections, it is poorly understood how ILC2s function in intestinal inflammation, including inflammatory bowel disease. Here, we analyzed the global gene expression of ILC2s in healthy and colitic conditions and revealed that type I interferon (T1IFN)-stimulated genes were up-regulated in ILC2s in dextran sodium sulfate (DSS)-induced colitis. The enhancement of T1IFN signaling in ILC2s in DSS-induced colitis was correlated with the downregulation of cytokine production by ILC2s, such as interleukin-5. Blocking T1IFN signaling during colitis resulted in exaggeration of colitis in both wild-type and Rag2-deficient mice. The exacerbation of colitis induced by neutralization of T1IFN signaling was accompanied by reduction of amphiregulin (AREG) in ILC2s and was partially rescued by exogenous AREG treatment. Collectively, these findings show the potential roles of T1IFN in ILC2s that contribute to colitis manifestation.

In addition to carcinogenesis, T helper 17 (Th17) cells (a subtype of CD4 + T lymphocytes) are involved in the acute, chronic, and cirrhotic phases of liver diseases; however, their role in the development and progression of liver diseases remains unclear. It is difficult to elucidate the role of Th17 cells in liver diseases due to their dichotomous nature, i.e., plasticity in terms of pathogenic or host protective function depending on environmental and time phase factors. Moreover, insufficient depletion of Th17 cells by inhibiting the cytokines and transcription factors involved in their production causes difficulties in analyzing their specific role in vitro and in vivo murine models, partially due to complex interaction. This review summarizes the recent progress in understanding the plasticity and function of hepatic Th17 cells and type 3 cytokines.

Diagnosing sarcopenia is challenging. This multicenter cross-sectional study aimed to evaluate the utility of the SARC-F score system for identifying sarcopenia in patients with chronic liver disease (CLD). We enrolled 717 patients from five participating centers who completed the SARC-F between November 2019 and March 2021. Sarcopenia was diagnosed based on the Japan Society of Hepatology Working Group on Sarcopenia in Liver Disease Consensus. Muscle strength was estimated using a grip dynamometer, and muscle mass was assessed using computed tomography or bioelectrical impedance analysis. The association between SARC-F and sarcopenia was analyzed using a logistic regression model. The optimal SARC-F cutoff value for identifying sarcopenia was determined using receiver operating characteristic (ROC) curve analysis. Of the 676 eligible patients, 15% were diagnosed with sarcopenia. The SARC-F distribution was 0 points in 63% of patients, 1 point in 17%, 2 points in 7%, 3 points in 4%, and ≥4 points in 8%. The SARC-F items of “Strength” (odds ratio (OR), 1.98; 95% confidence interval (CI), 1.03–3.80) and “Falls” (OR, 2.44; 95% CI, 1.48–4.03) were significantly associated with sarcopenia. The SARC-F value of 1 point showed a higher discriminative ability for identifying sarcopenia than the 4 points that are conventionally used (p < 0.001), with an area under the ROC curve of 0.68, sensitivity of 0.65, specificity of 0.68, positive predictive value of 0.27, and negative predictive value of 0.92. SARC-F is useful for identifying patients with CLD who are at risk of sarcopenia.

The pathophysiology of inflammatory bowel diseases (IBDs) involves immunological, genetic and environmental factors. Through its ability to sense environmental stimuli, the autonomic nervous system plays a key role in the development and persistence of IBDs. The vagus nerve (VN), which contains sensory and motor neurons, travels throughout the body to innervate the gut and other visceral organs in the thoracic and abdominopelvic cavities. Recent studies show that the VN has anti-inflammatory effects via the release of acetylcholine, in what is known as the cholinergic anti-inflammatory pathway (CAIP). In the gut immune system, the CAIP is proposed to be activated directly by signals from the gut and indirectly by signals from the liver, which receives gut-derived bioactive substances via the portal vein and senses the status of the gut. The gut-brain axis and liver-brain-gut reflex arc regulate a wide variety of peripheral immune cells to maintain homeostasis in the gut. Therefore, targeting the neural reflex by methods such as VN stimulation is now under investigation for suppressing intestinal inflammation associated with IBDs. In this review, we describe the role of the VN in the regulation of intestinal immunity, and we discuss novel therapeutic approaches for IBDs that target neuroimmune interactions.

BACKGROUND: We previously showed that knockdown of nuclear factor E2-related factor 2 (Nrf2) resulted in suppression of hepatitis C virus (HCV) infection. In this study, whether brusatol, an Nrf2 inhibitor, has dual anti-HCV and anticancer effects was explored. METHODS: The anti-HCV effect of brusatol was investigated by analyzing HCV RNA and proteins in a hepatic cell line persistently-infected with HCV, HPI cells, and by analyzing HCV replication in a replicon-replicating hepatic cell line, OR6 cells. Then, dual anti-HCV and anticancer effects of brusatol and enhancement of the effects by the combination of brusatol with anticancer drugs including sorafenib, which has been reported to have the dual effects, were then investigated. RESULTS: Brusatol suppressed the persistent HCV infection at both the RNA and protein levels in association with a reduction in Nrf2 protein in the HPI cells. Analysis of the OR6 cells treated with brusatol indicated that brusatol inhibited HCV persistence by inhibiting HCV replication. Combination of brusatol with an anticancer drug not only enhanced the anticancer effect but also, in the case of the combination with sorafenib, strongly suppressed HCV infection. CONCLUSIONS: Brusatol has dual anti-HCV and anticancer effects and can enhance the comparable effects of sorafenib. There is therefore the potential for combination therapy of brusatol and sorafenib for HCV-related hepatocellular carcinoma.

INTRODUCTION: Radiofrequency ablation (RFA) has been accepted as safe and effective for treating early-stage hepatocellular carcinoma (HCC). However, it often causes severe pain. Therefore, in this study, we performed RFA under deep sedation and investigated its efficacy and safety. METHODS: We conducted a retrospective study including 511 HCC patients who received approximately 886 RFA treatments between December 2014 and November 2016 at our institution. Respiratory depression was defined as oxygen saturation of below 90%; and severe body movement was defined as movement caused by pain, which was managed by lowering the power of the generator. Factors associated with respiratory depression and severe body movement were examined via univariate and multivariate regression analyses. RESULTS: Respiratory depression occurred in 15.3% of the patients and severe body movement in 26.5% of the patients. In the multivariate analysis, BMI (>/= 25 kg/m(2), odds ratio [OR] = 1.75, P = 0.035) and longer ablation (>/= 10 min, OR = 2.59, P = 0.002) were significant respiratory depression-related factors. Male sex (OR = 2.02, P = 0.005), Child-Pugh class A (odds ratio = 1.96, P = 0.018), and longer ablation (>/= 10 min, OR = 3.03, P < 0.001) were significant factors related to severe body movement. CONCLUSION: Deep sedation for RFA can be performed safely and effectively. Higher BMI and longer ablation were risk factors for respiratory depression and male sex, Child-Pugh class A, and longer ablation were independent predictors of severe body movement during RFA under deep sedation.

AIM: To elucidate associations among liver disease, lipid profile, body mass index (BMI), ketonuria, and meal skipping under the influence of alcohol dehydrogenase-1B (ADH1B; rs1229984) and aldehyde dehydrogenase-2 (ALDH2; rs671) genotypes in men with alcohol dependence. METHODS: We investigated the associations among these variables in 1768 Japanese men with alcohol dependence. Serum lipid levels were followed up after abstinence. RESULTS: The slow-metabolizing ADH1B Arg/Arg genotype and inactive ALDH2 Glu/Lys genotype increased the age- and drinking-adjusted odds ratio or regression coefficient for fatty liver, ketonuria, and serum high-density-lipoprotein cholesterol levels (HDL-C), and decreased these for cirrhosis and serum triglyceride levels (TG). The ADH1B Arg/Arg genotype increased the adjusted regression coefficient for BMI and non-HDL-C. In addition to the positive interlinkage among fatty liver, BMI, and atherogenic dyslipidemia, positive associations were observed of fatty liver with ketonuria and meal skipping, of cirrhosis with the BMI, and of ketonuria with non-HDL-C. Negative associations were observed of cirrhosis with fatty liver, TG, non-HDL-C, and HDL-C, and of ketonuria with BMI and TG. Overall, after admission for 4 or 6 weeks, the TG and HDL-C decreased, and the serum low-density lipoprotein cholesterol levels increased. However, there was no change of the serum low-density lipoprotein in the patients with cirrhosis or of the serum TG in those with fatty liver. CONCLUSIONS: These associations and the alterations in lipid profile after abstinence serve as useful information for a better understanding of the clinical features of men with alcohol dependence.

Recombinant human soluble thrombomodulin (rTM) was approved recently and has been used for treatment of disseminated intravascular coagulation (DIC). The aim of the present study was to evaluate the efficacy of rTM for DIC. The data of 53 inpatients with sepsis-induced DIC were retrospectively analyzed. Patients were classified into the rTM treatment group (n=25) and conventional treatment group (rTM not used) was the control group (n=28). Diagnosis of DIC was made according to the criteria for acute DIC of the Japan Association of Acute Medicine. Platelet count, prothrombin time-international normalized ratio, levels of fibrin/fibrinogen degradation products (FDP), C-reactive protein and DIC scores were measured on days 0, 3 and 7. Furthermore, the DIC resolution rate was assessed on days 3 and 7. Prior to treatment, DIC scores were 5.0+/-1.0 in the rTM group and 5.9+/-1.3 in the control group (P<0.05). Significant intra-group improvements were observed in all the parameters, except for FDP in the two groups. Significant improvements were observed in the DIC scores in the rTM group (Delta2.0+/-1.9 vs. Delta1.5+/-1.9, P=0.001). Therefore, the results suggest that rTM would be a useful medicine for treatment of DIC in the gastroenterology field.

Hepatitis C virus (HCV) genotype 1 infections are significantly more difficult to eradicate with PEG-IFN/ribavirin therapy, compared to HCV genotype 2. The aim of this work is to investigate the difference of immunological impairments underlying this phenomenon. Pre-treatment NKG2D expression on peripheral CD56+CD3+ lymphocytes and CD56+CD3- NK cells from cases of chronic hepatitis C were analyzed and assessed by treatment effect. Two strains of HCV were used to co-incubate with immune cells in vitro. NKG2D expression on peripheral CD56+CD3+ lymphocytes, but not NK cells, was significantly impaired in genotype 1 infection, compared to genotype 2. When peripheral blood mononuclear cells from healthy donors were co-incubated with TNS2J1, a genotype 1b/2a chimera strain, or with JFH1, a genotype 2a strain, genotype-specific decrease of NKG2D on CD56+CD3+ lymphocytes, but not NK cells, was observed.Pre-treatment NKG2D expression on peripheral CD56+CD3+ lymphocytes significantly correlated with reduction in serum HCV RNA levels from week 0 to week 4, and predicted treatment response. Ex vivo stimulation of peripheral CD56+CD3+ lymphocytes showed NKG2D expression-correlated IFN-gamma production. In conclusion, Decreased NKG2D expression on CD56+CD3+ lymphocytes in chronic HCV genotype 1 infection predicts inferior treatment response to PEG-IFN/ribavirin therapy compared to genotype 2.

A prognostic system for acute liver failure (ALF) with a higher predictive value is urgently needed. The role of extracellular matrix (ECM) remodeling in ALF has not been fully elucidated. We hypothesized that serologic fibrosis markers, which reflect ECM remodeling, are predictive of ALF outcome at first presentation. This observational study included 110 patients with acute liver dysfunction, of which 73 had non-acetaminophen-associated ALF (NAA-ALF). We evaluated serum levels of hyaluronic acid, 7S domain of type IV collagen (4COL7S), and Wisteria floribunda agglutinin-positive Mac-2-binding protein at first presentation to a tertiary center. Serologic fibrosis markers were significantly higher in NAA-ALF compared with acute hepatitis. Elevated hyaluronic acid and 4COL7S levels at first presentation correlated significantly with worse clinical outcomes. 4COL7S, along with age, ammonia, and the Model for End-Stage Liver Disease (MELD) score, was a significant prognostic factor in multivariate analysis; 4COL7S correlated significantly with coagulopathy, decreased hepatic synthetic functions, advanced hepatic encephalopathy, and liver atrophy and also predicted 180-day transplant-free survival. Cox regression models incorporating 4COL7S with the MELD system had profoundly improved predictive values that significantly surpassed the MELD system alone. Conclusion: Elevation of serologic fibrosis markers reflecting ECM remodeling in NAA-ALF predicted a worse clinical outcome. Incorporation of 4COL7S at first presentation to a transplant center improves the specificity while retaining the sensitivity of the MELD system. External validation of a fibrosis marker as part of a clinical prediction tool in ALF warrants further investigation.

BACKGROUND AND AIMS: Interferon (IFN)- free direct antiviral agents (DAAs) with rapid HCV eradication might evoke immunological reconstitutions, and some early recurrences of HCC after IFN-free DAAs have been reported. This study aimed to investigate whether natural killer group 2, member D (NKG2D) predicts early emergence of HCC after IFN-free DAAs. METHODS: We conducted a clinical practice-based observational study of 101 patients infected with genotype 1 HCV who received IFN-free (DAAs), and stratified them into those who did or did not develop early (i.e., during the 6-month surveillance period following treatment.) recurrence or occurrence of clinically evident HCC. We also analyzed the peripheral blood mononuclear cells, both before treatment and at end of treatment (EOT), of 24 of the patients who received IFN-free DAAs, and 16 who received IFN-combined protease inhibitor. RESULTS: We found early emergence of clinically evident HCC after IFN-free DAAs in 12 (12%) patients. Higher pre-treatment NKG2D expression, higher FIB-4 score, previous HCC history and failure to achieve sustained viral response were significant factors correlating to early HCC emergence. After IFN-free DAAs, a rapid decrease of NKG2D at EOT correlated with early HCC emergence in the IFN-free DAA-treated patients, but not in patients treated with the IFN-combined regimen. The decrease of NKG2D until EOT was predictive of early HCC emergence at a cut-off of -52% (AUC = 0.92). CONCLUSIONS: On-treatment decrease of NKG2D may be a useful predictor of early emerging HCC in patients treated with IFN-free DAAs.