Priming and Maintenance of Adaptive Immunity in the Liver.

The liver's unique characteristics have a profound impact on the priming and maintenance of adaptive immunity. This review delves into the cellular circuits that regulate adaptive immune responses in the liver, with a specific focus on hepatitis B virus infection as an illustrative example. A key aspect highlighted is the liver's specialized role in priming CD8+ T cells, leading to a distinct state of immune hyporesponsiveness. Additionally, the influence of the liver's hemodynamics and anatomical features, particularly during liver fibrosis and cirrhosis, on the differentiation and function of adaptive immune cells is discussed. While the primary emphasis is on CD8+ T cells, recent findings regarding the involvement of B cells and CD4+ T cells in hepatic immunity are also reviewed. Furthermore, we address the challenges ahead and propose integrating cutting-edge techniques, such as spatial biology, and combining mouse models with human sample analyses to gain comprehensive insights into the liver's adaptive immunity. This understanding could pave the way for novel therapeutic strategies targeting infectious diseases, malignancies, and inflammatory liver conditions like nonalcoholic steatohepatitis and autoimmune hepatitis. Expected final online publication date for the Annual Review of Immunology, Volume 42 is April 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

CD8 cis-targeted IL-2 drives potent antiviral activity against hepatitis B virus.

CD8+ T cells are key antiviral effectors against hepatitis B virus (HBV), yet their number and function can be compromised in chronic infections. Preclinical HBV models displaying CD8+ T cell dysfunction showed that interleukin-2 (IL-2)-based treatment, unlike programmed cell death ligand 1 (PD-L1) checkpoint blockade, could reverse this defect, suggesting its therapeutic potential against HBV. However, IL-2's effectiveness is hindered by its pleiotropic nature, because its receptor is found on various immune cells, including regulatory T (Treg) cells and natural killer (NK) cells, which can counteract antiviral responses or contribute to toxicity, respectively. To address this, we developed a cis-targeted CD8-IL2 fusion protein, aiming to selectively stimulate dysfunctional CD8+ T cells in chronic HBV. In a mouse model, CD8-IL2 boosted the number of HBV-reactive CD8+ T cells in the liver without substantially altering Treg or NK cell counts. These expanded CD8+ T cells exhibited increased interferon-γ and granzyme B production, demonstrating enhanced functionality. CD8-IL2 treatment resulted in substantial antiviral effects, evidenced by marked reductions in viremia and antigenemia and HBV core antigen-positive hepatocytes. In contrast, an untargeted CTRL-IL2 led to predominant NK cell expansion, minimal CD8+ T cell expansion, negligible changes in effector molecules, and minimal antiviral activity. Human CD8-IL2 trials in cynomolgus monkeys mirrored these results, achieving a roughly 20-fold increase in peripheral blood CD8+ T cells without affecting NK or Treg cell numbers. These data support the development of CD8-IL2 as a therapy for chronic HBV infection.

Increased spine bone density in patients with chronic hepatitis B switched to tenofovir alafenamide: A prospective, multinational study.

BACKGROUND: Data on patients switched to tenofovir alafenamide (TAF) from nucleos(t)ide analogues (NUCs) other than tenofovir disoproxil fumarate are limited. AIMS: To assess the treatment and renal/bone safety outcomes following the switch to TAF. METHODS: We prospectively enrolled adult patients with chronic hepatitis B (CHB) who switched from any NUC to TAF at 14 centres in Japan, Korea, Taiwan and the U.S. Study outcomes were viral suppression (VR; HBV DNA < 20 IU/mL), biochemical response (BR; alanine aminotransferase normalisation), and changes in estimated glomerular filtration rate (eGFR) and T-scores (L-spine) by bone absorptiometry by 24 months after switch to TAF. RESULTS: We enrolled 270 eligible patients. Mean age was 58.1; 58.2% were male; 12.2% had cirrhosis and 73.3% previously received entecavir monotherapy. VR rate increased significantly from 95.2% to 98.8% by 24 months after the switch to TAF (p = 0.014). Between the switch and 24 months later, the mean spine T-score improved significantly from -1.43 ± 1.36 to -1.17 ± 1.38 (p < 0.0001), while there was no significant change in mean eGFR (88.4 ± 16.9-89.5 ± 16.3 mL/min/1.73 m2 , p = 0.13). On multivariable analysis adjusted for age, sex, baseline spine T-score and prior TDF or adefovir dipivoxil use, male sex was significantly associated with lower risk of worsening spine T-score (odds ratio: 0.29, p = 0.020), while age was significantly associated with a higher risk of worsening chronic kidney disease stage (OR: 1.07, p = 0.019). CONCLUSIONS: At 24 months after the switch to TAF, VR rates and spine bone density improved significantly while renal function remained stable.

Sex Differences in Treatment Response to Nucleos(t)ide Therapy in Chronic Hepatitis B: A Multicenter Longitudinal Study.

BACKGROUND & AIMS: It is unclear if there may be sex differences in response to nucleos(t)ide analogs including virologic response (VR), biochemical response (BR), complete response (CR), and hepatocellular carcinoma (HCC) incidence among hepatitis B patients. We compared nucleos(t)ide analog treatment outcomes by sex. METHODS: We performed a retrospective cohort study of 3388 treatment-naïve adult hepatitis B patients (1250 female, 2138 male) from the Real-World Evidence from the Global Alliance for the Study of Hepatitis B Virus consortium who initiated therapy with either entecavir or tenofovir from 22 sites (Argentina, Korea, Japan, Taiwan, and the United States). We used propensity-score matching to balance background characteristics of the male and female groups and competing-risks analysis to estimate the incidence and subdistribution hazard ratios (SHRs) of VR, BR, CR, and HCC. RESULTS: Females (vs males) were older (52.0 vs 48.6 y); less likely to be overweight/obese (49.3% vs 65.7%), diabetic (9.9% vs 13.1%), or cirrhotic (27.9% vs 33.0%); and had a lower HBV DNA level (5.9 vs 6.0 log10 IU/mL) and alanine aminotransferase level (91 vs 102 IU/L) (all P < .01). However, after propensity-score matching, relevant background characteristics were balanced between the 2 groups. Females (vs males) had similar 5-year cumulative VR (91.3% vs 90.3%; P = .40) and HCC incidence rates (5.1% vs 4.4%; P = .64), but lower BR (84.0% vs 90.9%; P < .001) and CR (78.8% vs 83.4%; P = .016). Males were more likely to achieve BR (SHR, 1.31; 95% CI, 1.17-1.46; P < .001) and CR (SHR, 1.16; 95% CI, 1.03-1.31; P = .016), but VR and HCC risks were similar. CONCLUSIONS: Sex differences exist for treatment outcomes among hepatitis B patients. Male sex was associated with a 16% higher likelihood of clinical remission and a 31% higher likelihood of biochemical response than females, while virologic response and HCC incidence were similar between the 2 groups.

Droplet digital PCR assay provides intrahepatic HBV cccDNA quantification tool for clinical application.

The persistence of covalently closed circular DNA (cccDNA) poses a major obstacle to curing chronic hepatitis B (CHB). Here, we used droplet digital PCR (ddPCR) for cccDNA quantitation. The cccDNA-specific ddPCR showed high accuracy with the dynamic range of cccDNA detection from 101 to 105 copies/assay. The ddPCR had higher sensitivity, specificity and precisely than qPCR. The results of ddPCR correlated closely with serum HB core-related antigen and HB surface antigen (HBsAg) in 24 HBV-infected human-liver-chimeric mice (PXB-mice). We demonstrated that in 2 PXB-mice after entecavir treatment, the total cccDNA content did not change during liver repopulation, although the cccDNA content per hepatocyte was reduced after the treatment. In the 6 patients with HBV-related hepatocellular carcinoma, ddPCR detected cccDNA in both tumor and non-tumor tissues. In 13 HBeAg-negative CHB patients with pegylated interferon alpha-2a, cccDNA contents from paired biopsies were more significantly reduced in virological response (VR) than in non-VR at week 48 (p = 0.0051). Interestingly, cccDNA levels were the lowest in VR with HBsAg clearance but remained detectable after the treatment. Collectively, ddPCR revealed that cccDNA content is stable during hepatocyte proliferation and persists at quantifiable levels, even after serum HBsAg clearance.

Bile acid dysmetabolism in the gut-microbiota-liver axis under hepatitis C virus infection.

BACKGROUND & AIMS: We recently analysed and reported the features of the micro biome under hepatitis C virus (HCV) infection, but the effect of HCV infection on bile acid (BA) metabolism in the gut-liver axis remains poorly understood. The aim of this study was to clarify the characteristics of the gut-liver axis in HCV-infected patients. METHODS: The faecal BAs composition and gut microbiota from 100 chronic hepatitis C (CHC) patients were compared with those from 23 healthy individuals. For transcriptional analysis of the liver, 22 mild CHC (fibrosis stages [F] 0-2) and 42 advanced CHC (F3-4) cases were compared with 12 healthy individuals. The findings were confirmed using chimeric mice with human hepatocytes infected with HCV HCR6. RESULTS: Chronic hepatitis C patients, even at earlier disease stages, showed BA profiles distinct from healthy individuals, in which faecal deoxycholic acid (DCA) was significantly reduced and lithocholic acid or ursodeoxycholic acid became dominant. The decrease in faecal DCA was correlated with reduction in commensal Clostridiales and increase in oral Lactobacillales. Impaired biosynthesis of cholic acid (CA) was observed as a reduction in the transcription level of cytochrome P450 8B1 (CYP8B1), a key enzyme in CA biosynthesis. The reductions in faecal DCA and liver CYP8B1 were also observed in HCV-infected chimeric mice. CONCLUSIONS: Chronic hepatitis C alters the intestinal BA profile, in association with the imbalance of BA biosynthesis, which differs from the pattern in NAFLD. These imbalances appear to drive disease progression through the gut-microbiome-liver axis.

A New Species of Pseudostrandesia Savatenalinton and Martens, 2009 (Ostracoda, Crustacea) Collected from Two Pet Shops in Central Japan: an Alien Species?

An undescribed species of freshwater ostracod belonging to the genus Pseudostrandesia Savatenalinton and Martens, 2009 was collected from two pet shops in the Kanto region of central Japan. This species, herein named Pseudostrandesia tenebrarum sp. nov., is similar to four species previously reported from Southeast Asia, but can be distinguished by carapace and appendage features. It is the second species of the genus for which males are known. Of the nine previously described species in the genus, one is exclusively known from Turkey, and the others are found in Southeast Asia and the vicinity, one of which is also recorded in India and east China. There are two scenarios to explain the existence of Pseudostrandesia tenebrarum sp. nov. in pet shops in Japan: it is either native to Japan but has yet to be discovered in its natural habitat, or it is an alien species, perhaps unwittingly imported with plants or fish for the pet trade. We review the likelihood of both scenarios, and conclude that although there is insufficient evidence to be sure, it is potentially an alien species in Japan. The most likely origin is Southeast Asia, as evidenced by its close morphological resemblance to particular Southeast Asian species. Juveniles as well as adults were recovered, indicating that this species is reproducing in the pet trade, supporting the notion that it has invasive potential to areas outside of its natural range. The description and report of this species highlights a possible introduction of an alien species to Japan, and facilitates further monitoring.

HBV-Specific CD8+ T-Cell Tolerance in the Liver.

Hepatitis B virus (HBV) remains a leading cause of liver-related morbidity and mortality through chronic hepatitis that may progress to liver cirrhosis and cancer. The central role played by HBV-specific CD8+ T cells in the clearance of acute HBV infection, and HBV-related liver injury is now well established. Vigorous, multifunctional CD8+ T cell responses are usually induced in most adult-onset HBV infections, while chronic hepatitis B (CHB) is characterized by quantitatively and qualitatively weak HBV-specific CD8+ T cell responses. The molecular basis of this dichotomy is poorly understood. Genomic analysis of dysfunctional HBV-specific CD8+ T cells in CHB patients and various mouse models suggest that multifaceted mechanisms including negative signaling and metabolic abnormalities cooperatively establish CD8+ T cell dysfunction. Immunoregulatory cell populations in the liver, including liver resident dendritic cells (DCs), hepatic stellate cells (HSCs), myeloid-derived suppressor cells (MDSCs), may contribute to intrahepatic CD8+ T cell dysfunction through the production of soluble mediators, such as arginase, indoleamine 2,3-dioxygenase (IDO) and suppressive cytokines and the expression of co-inhibitory molecules. A series of recent studies with mouse models of HBV infection suggest that genetic and epigenetic changes in dysfunctional CD8+ T cells are the manifestation of prolonged antigenic stimulation, as well as the absence of co-stimulatory or cytokine signaling. These new findings may provide potential new targets for immunotherapy aiming at invigorating HBV-specific CD8+ T cells, which hopefully cures CHB.

Interferon signaling suppresses the unfolded protein response and induces cell death in hepatocytes accumulating hepatitis B surface antigen.

Virus infection, such as hepatitis B virus (HBV), occasionally causes endoplasmic reticulum (ER) stress. The unfolded protein response (UPR) is counteractive machinery to ER stress, and the failure of UPR to cope with ER stress results in cell death. Mechanisms that regulate the balance between ER stress and UPR are poorly understood. Type 1 and type 2 interferons have been implicated in hepatic flares during chronic HBV infection. Here, we examined the interplay between ER stress, UPR, and IFNs using transgenic mice that express hepatitis B surface antigen (HBsAg) (HBs-Tg mice) and humanized-liver chimeric mice infected with HBV. IFNα causes severe and moderate liver injury in HBs-Tg mice and HBV infected chimeric mice, respectively. The degree of liver injury is directly correlated with HBsAg levels in the liver, and reduction of HBsAg in the transgenic mice alleviates IFNα mediated liver injury. Analyses of total gene expression and UPR biomarkers' protein expression in the liver revealed that UPR is induced in HBs-Tg mice and HBV infected chimeric mice, indicating that HBsAg accumulation causes ER stress. Notably, IFNα administration transiently suppressed UPR biomarkers before liver injury without affecting intrahepatic HBsAg levels. Furthermore, UPR upregulation by glucose-regulated protein 78 (GRP78) suppression or low dose tunicamycin alleviated IFNα mediated liver injury. These results suggest that IFNα induces ER stress-associated cell death by reducing UPR. IFNγ uses the same mechanism to exert cytotoxicity to HBsAg accumulating hepatocytes. Collectively, our data reveal a previously unknown mechanism of IFN-mediated cell death. This study also identifies UPR as a potential target for regulating ER stress-associated cell death.

Restoration of type I interferon signaling in intrahepatically primed CD8+ T cells promotes functional differentiation.

Hepatitis B virus-specific (HBV-specific) CD8+ T cells fail to acquire effector functions after priming in the liver, but the molecular basis for the dysfunction is poorly understood. By comparing the gene expression profile of intrahepatically primed, dysfunctional HBV-specific CD8+ T cells with that of systemically primed, functional effector counterparts, we found that the expression of interferon-stimulated genes (ISGs) is selectively suppressed in the dysfunctional CD8+ T cells. The ISG suppression was associated with impaired phosphorylation of STAT1 in response to IFN-α treatment. Importantly, a strong induction of type I interferons (IFN-Is) in the liver facilitated the functional differentiation of intrahepatically primed HBV-specific CD8+ T cells in association with the restoration of ISGs' expression in the T cells. These results suggest that intrahepatic priming suppresses IFN-I signaling in CD8+ T cells, which may contribute to the dysfunction. The data also suggest a therapeutic value of the robust induction of intrahepatic IFN-Is for the treatment of chronic HBV infection.

Inhibitory Effect of a Human MicroRNA, miR-6133-5p, on the Fibrotic Activity of Hepatic Stellate Cells in Culture.

BACKGROUND: We recently identified 39 human microRNAs, which effectively suppress hepatitis B virus (HBV) replication in hepatocytes. Chronic HBV infection often results in active, hepatitis-related liver fibrosis; hence, we assessed whether any of these microRNAs have anti-fibrotic potential and predicted that miR-6133-5p may target several fibrosis-related genes. METHODS: The hepatic stellate cell line LX-2 was transfected with an miR-6133-5p mimic and subsequently treated with Transforming growth factor (TGF)-ß. The mRNA and protein products of the COL1A1 gene, encoding collagen, and the ACTA2 gene, an activation marker of hepatic stellate cells, were quantified. RESULTS: The expression of COL1A1 and ACTA2 was markedly reduced in LX-2 cells treated with miR-6133-5p. Interestingly, phosphorylation of c-Jun N-terminal kinase (JNK) was also significantly decreased by miR-6133-5p treatment. The expression of several predicted target genes of miR-6133-5p, including TGFBR2 (which encodes Transforming Growth Factor Beta Receptor 2) and FGFR1 (which encodes Fibroblast Growth Factor Receptor 1), was also reduced in miR-6133-5p-treated cells. The knockdown of TGFBR2 by the corresponding small interfering RNA greatly suppressed the expression of COL1A1 and ACTA2. Treatment with the JNK inhibitor, SP600125, also suppressed COL1A1 and ACTA2 expression, indicating that TGFBR2 and JNK mediate the anti-fibrotic effect of miR-6133-5p. The downregulation of FGFR1 may result in a decrease of phosphorylated Akt, ERK (extracellular signal-regulated kinase), and JNK. CONCLUSION: miR-6133-5p has a strong anti-fibrotic effect, mediated by inactivation of TGFBR2, Akt, and JNK.

The antiviral effects of human microRNA miR-302c-3p against hepatitis B virus infection.

BACKGROUND: Conventional treatments of chronic hepatitis B virus (HBV) infection rarely achieve a decline of serum hepatitis B surface antigen (HBsAg) levels and eradication of the virus. AIM: To elucidate the antiviral mechanisms of a human microRNA, miR-302c-3p, against HBV replication. METHODS: The antiviral effect of miR-302c-3p was evaluated in vitro and in vivo by transfecting the miR-302c-3p mimic into HBV-infected HepG2-hNTCP-C4 cells and HBV transgenic mice respectively. RESULTS: miR-302c-3p decreased not only HBV replication but also production of HBsAg. Pregenomic RNA and HBsAg mRNA concentrations decreased in the cells treated with miR-302c-3p. Interestingly, the amount of cccDNA was significantly reduced in the miR-302c-3p-treated cells, in association with disappearance of the HBV core protein. An RNA immunoprecipitation assay showed that miR-302c-3p decreased the binding of the HBV polymerase to the pregenomic RNA by hybridising with the ε-loop region. A number of host genes were downregulated in miR-302c-3p-treated cells, including BMPR2 and HNF4A. Knockdown of these two genes by corresponding siRNAs also suppressed HBV replication and HBsAg secretion. The antiviral effect of miR-302c-3p was also observed in HBV transgenic mice. CONCLUSION: miR-302c-3p had anti-HBV activity, in vitro and in vivo, via several mechanisms.

An Association Between Core Mutations in Hepatitis B Virus Genotype F1b and Hepatocellular Carcinoma in Alaskan Native People.

Hepatitis B virus (HBV) genotype F1b infection is strongly associated with hepatocellular carcinoma (HCC) in young Alaskan Native (AN) people. However, the mechanisms by which genotype F1b causes HCC are unclear. Here, we analyzed the clinical and virological significance of genotype F1b in long-term serial samples from 20 HCC patients with HBV infection. Complete sequence analyses revealed that all isolates were genotype F1b. In the HCC patients, T1938C and A2051C mutations in the core region had accumulated significantly with A1762T/G1764A mutations in the basal core promoter (BCP) region and G1896A mutation in the precore (PC) region. Several HBV clones containing the core mutations were examined for their replication efficiency and core stability in vitro. Clones containing the A2051C mutation replicated more efficiently than the wild type in association with enhanced stability of core protein dimerization. In chimeric mice with human hepatocytes carrying BCP/PC/2051 mutant but not with wild-type virus, liver fibrosis was induced in association with high levels of serum HBV DNA and hepatitis B surface antigen. Interestingly, microarray analysis and validation study showed that five genes associated with cell proliferation or carcinogenesis, v-myc avian myelocytomatosis viral oncogene homolog, Grb2-associated binding protein 2, bradykinin receptor B2, follistatin, and mitogen-activated protein kinase kinase kinase 8, were significantly up-regulated in human hepatocytes infected with genotype F1b, particularly the BCP/PC/2051 mutant, compared with other genotypes. Conclusion: We have identified an association between Alaska-specific core mutations and HCC development in AN people infected with genotype F1b; accumulation of these core mutations during the course of chronic infection with genotype F1b would contribute to HCC development in AN people earlier in life.

Type I Interferon Signaling Prevents Hepatitis B Virus-Specific T Cell Responses by Reducing Antigen Expression.

Robust virus-specific CD8+ T cell responses are required for the clearance of hepatitis B virus (HBV). However, the factors that determine the magnitude of HBV-specific CD8+ T cell responses are poorly understood. To examine the impact of genetic variations of HBV on HBV-specific CD8+ T cell responses, we introduced three HBV clones (Aa_IND [Aa], C_JPN22 [C22], and D_IND60 [D60]) that express various amounts of HBV antigens into the livers of C57BL/6 (B6) (H-2b) mice and B10.D2 (H-2d) mice. In B6 mice, clone C22 barely induced HBV-specific CD8+ T cell responses and persisted the longest, while clone D60 elicited strong HBV-specific CD8+ T cell responses and was rapidly cleared. These differences between HBV clones largely diminished in H-2d mice. Interestingly, the magnitude of HBV-specific CD8+ T cell responses in B6 mice was associated with the HB core antigen expression level during the early phase of HBV transduction. Surprisingly, robust HBV-specific CD8+ T cell responses to clone C22 were induced in interferon-α/ß receptor-deficient (IFN-αßR-/-) (H-2b) mice. The induction of HBV-specific CD8+ T cell responses to C22 in IFN-αßR-/- mice reflects enhanced HBV antigen expression because the suppression of antigen expression by HBV-specific small interfering RNA (siRNA) attenuated HBV-specific T cell responses in IFN-αßR-/- mice and prolonged HBV expression. Collectively, these results suggest that HBV genetic variation and type I interferon signaling determine the magnitude of HBV-specific CD8+ T cell responses by regulating the initial antigen expression levels.IMPORTANCE Hepatitis B virus (HBV) causes acute and chronic infection, and approximately 240 million people are chronically infected with HBV worldwide. It is generally believed that virus-specific CD8+ T cell responses are required for the clearance of HBV. However, the relative contributions of genetic variation and innate immune responses to the induction of HBV-specific CD8+ T cell responses are not fully understood. In this study, we discovered that different clearance rates between HBV clones after hydrodynamic transduction were associated with the magnitude of HBV-specific CD8+ T cell responses and initial HB core antigen expression. Surprisingly, type I interferon signaling negatively regulated HBV-specific CD8+ T cell responses by reducing early HBV antigen expression. These results show that the magnitude of the HBV-specific CD8+ T cell response is regulated primarily by the initial antigen expression level.

Intrahepatic Cross-Presentation and Hepatocellular Antigen Presentation Play Distinct Roles in the Induction of Hepatitis B Virus-Specific CD8+ T Cell Responses.

CD8+ T cells are the key cellular effectors mediating the clearance of hepatitis B virus (HBV) infections. However, early immunological events surrounding the priming of HBV-specific CD8+ T cell responses remain poorly understood. This study examined the importance of priming location and the relative contribution of endogenous antigen presentation by hepatocytes versus cross-presentation by bone marrow-derived cells to the induction of functional HBV-specific CD8+ T cell responses using the animal models of acute and chronic HBV infection. Functional HBV-specific CD8+ T cell responses could be induced to intrahepatically expressed HBV even when T cell homing to the lymphoid tissues was severely suppressed, suggesting that functional priming could occur in the liver. The expansion of HBV-specific CD8+ T cells was significantly reduced in the mice whose major histocompatibility complex (MHC) class I expression was mostly restricted to nonhematopoietic cells, suggesting the importance of cross-presentation by hematopoietic cells in the induction of HBV-specific CD8+ T cells. Strikingly, the expansion and cytolytic differentiation of HBV-specific CD8+ T cells were reduced even more severely in the mice whose MHC class I expression was restricted to hematopoietic cells. Collectively, these results indicate that cross-presentation is required but relatively inefficient in terms of inducing the cytolytic differentiation of HBV-specific CD8+ T cells by itself. Instead, the expansion and functional differentiation of HBV-specific CD8+ T cells are primarily dependent on hepatocellular antigen presentation.IMPORTANCE Hepatitis B virus (HBV) causes acute and chronic hepatitis. Approximately 260 million people are chronically infected with HBV and under an increased risk of developing cirrhosis and hepatocellular carcinoma. Host immune responses, particularly HBV-specific CD8+ T cell responses, largely determine the outcome of HBV infection. It is widely accepted that antigen inexperienced CD8+ T cells should be initially activated by professional antigen-presenting cells (pAPCs) in lymphoid tissues to differentiate into effector CD8+ T cells. However, this notion has not been tested for HBV-specific CD8+ T cells. In this study, we show that HBV-specific CD8+ T cell responses can be induced in the liver. Surprisingly, antigen presentation by hepatocytes is more important than cross-presentation by hematopoietic cells for the induction of HBV-specific CD8+ T cell responses. These results revealed a previously unappreciated role of antigen presentation by hepatocytes in the induction of HBV-specific CD8+ T cell responses.

Non-alcoholic fatty liver disease comorbid with major depressive disorder: The pathological features and poor therapeutic efficacy.

BACKGROUND AND AIM: Major depressive disorder (MDD) is an important public health problem, and it is often comorbid with many chronic diseases. The purpose of this study was to identify the clinical features of non-alcoholic fatty liver disease (NAFLD) patients comorbid with MDD and to investigate the influence of MDD on the effect of treatment in patients with NAFLD. METHODS: A total of 258 patients with biopsy-proven NAFLD were included. MDD was diagnosed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision. The patients were followed up for 48 weeks under standard care for NAFLD, which consisted mainly of lifestyle modification. RESULTS: There were 32 patients comorbid with MDD. They were characterized by more severe histological steatosis and higher NAFLD activity score, and also significantly higher levels of serum aminotransferase, γ-glutamyl transpeptidase and ferritin, than age-and-sex-matched NAFLD patients without MDD. Moreover, NAFLD patients with MDD showed poor response to the standard care for NAFLD, in body weight loss and in other parameters. Particularly, NAFLD patients with unstable MDD (not in full/partial remission) showed severe resistance to the treatment. CONCLUSION: This is the first study to demonstrate the clinical features and response to therapy of NAFLD patients comorbid with MDD. The comorbid state of MDD was associated with more severe histological liver steatosis and worse treatment outcomes in patients with NAFLD. Further investigations are required to develop new lifestyle modification programs that enable NAFLD patients with MDD to achieve the treatment goal.

Non-alcoholic fatty liver disease adversely affects the glycemic control afforded by sitagliptin.

BACKGROUND/AIMS: Recently, high serum DPP-4 activity was found in patients with NAFLD. Therefore, the possibility of NAFLD adversely influencing the therapeutic effect afforded by DPP-4 inhibitors in type 2 diabetic patients was suggested. METHODOLOGY: A total of 20 type 2 DM patients with NAFLD and 85 type 2 DM patients without NAFLD were enrolled in the present study. The patients were administered sitagliptin at the dose of 50 mg/day for 12 weeks. RESULTS: The change in HbA1c from the baseline following treatment with sitagliptin was -0.47% (4 weeks), -0.73% (8 weeks) and -0.88% (12 weeks) in the type 2 DM patients with NAFLD and -0.26% (4 weeks), -0.41% (8 weeks) and -0.49% (12 weeks) in type 2 DM without NAFLD. The changes in the HbA1c from the baseline after sitagliptin treatment for 8 and 12 weeks were significantly greater in type 2 DM patients with NAFLD than in type 2 DM patients without NAFLD. CONCLUSIONS: The results of this study suggest that NAFLD might adversely affect the therapeutic effect afforded by sitagliptin treatment in patients with type 2 DM. NAFLD may be an independent predictor of the effect of sitagliptin in patients with type 2 DM.