Safety and preliminary efficacy of pembrolizumab following trans-arterial chemoembolization for hepatocellular carcinoma: the PETAL phase Ib study.

BACKGROUND: TACE may prime adaptive immunity and enhance immunotherapy efficacy. PETAL evaluated safety, preliminary activity of TACE plus pembrolizumab and explored mechanisms of efficacy. METHODS: Patients with liver-confined HCC were planned to receive up to 2 rounds of TACE followed by pembrolizumab 200 mg every 21 days commencing 30-days post-TACE until disease progression or unacceptable toxicity for up to 1 year. Primary endpoint was safety, 21-days dose-limiting toxicities (DLT) from pembrolizumab initiation. Secondary endpoints included progression-free survival (PFS) and evaluation of tumour and host determinants of response. RESULTS: Fifteen patients were included in the safety and efficacy population: 73% had non-viral cirrhosis, median age was 72 years. Child-Pugh (CP) class was A in 14 patients. Median tumour size was 4 cm. Ten patients (67%) received pembrolizumab after 1 TACE, 5 patients after 2 (33%). Pembrolizumab yielded no synergistic toxicity nor DLTs post-TACE. Treatment-related adverse events occurred in 93% of patients most commonly skin rash (40%), fatigue and diarrhoea (27%). After a median follow-up of 38.5 months, objective response rate (ORR) 12 weeks post-TACE was 53%. PFS rate at 12 weeks was 93% and median PFS was 8.95 months (95%CI 7.30-NA). Median duration of response was 7.3 months (95%CI: 6.3-8.3). Median OS was 33.5 months (95%CI: 11.6-NA). Dynamic changes in peripheral T-cell subsets, circulating tumour DNA, serum metabolites and in stool bacterial profiles highlight potential mechanisms of action of multi-modal therapy. CONCLUSIONS: TACE plus pembrolizumab was tolerable with no evidence of synergistic toxicity, encouraging further clinical development of immunotherapy alongside TACE.

Therapeutic inhibition of monocyte recruitment prevents checkpoint inhibitor-induced hepatitis.

BACKGROUND: Checkpoint inhibitor-induced hepatitis (CPI-hepatitis) is an emerging problem with the widening use of CPIs in cancer immunotherapy. Here, we developed a mouse model to characterize the mechanism of CPI-hepatitis and to therapeutically target key pathways driving this pathology. METHODS: C57BL/6 wild-type (WT) mice were dosed with toll-like receptor (TLR)9 agonist (TLR9-L) for hepatic priming combined with anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) plus anti-programmed cell death 1 (PD-1) ("CPI") or phosphate buffered saline (PBS) control for up to 7 days. Flow cytometry, histology/immunofluorescence and messenger RNA sequencing were used to characterize liver myeloid/lymphoid subsets and inflammation. Hepatocyte damage was assessed by plasma alanine transaminase (ALT) and cytokeratin-18 (CK-18) measurements. In vivo investigations of CPI-hepatitis were carried out in Rag2-/- and Ccr2rfp/rfp transgenic mice, as well as following anti-CD4, anti-CD8 or cenicriviroc (CVC; CCR2/CCR5 antagonist) treatment. RESULTS: Co-administration of combination CPIs with TLR9-L induced liver pathology closely resembling human disease, with increased infiltration and clustering of granzyme B+perforin+CD8+ T cells and CCR2+ monocytes, 7 days post treatment. This was accompanied by apoptotic hepatocytes surrounding these clusters and elevated ALT and CK-18 plasma levels. Liver RNA sequencing identified key signaling pathways (JAK-STAT, NF-ΚB) and cytokine/chemokine networks (Ifnγ, Cxcl9, Ccl2/Ccr2) as drivers of CPI-hepatitis. Using this model, we show that CD8+ T cells mediate hepatocyte damage in experimental CPI-hepatitis. However, their liver recruitment, clustering, and cytotoxic activity is dependent on the presence of CCR2+ monocytes. The absence of hepatic monocyte recruitment in Ccr2rfp/rfp mice and CCR2 inhibition by CVC treatment in WT mice was able to prevent the development and reverse established experimental CPI-hepatitis. CONCLUSION: This newly established mouse model provides a platform for in vivo mechanistic studies of CPI-hepatitis. Using this model, we demonstrate the central role of liver infiltrating CCR2+ monocyte interaction with tissue-destructive CD8+ T cells in the pathogenesis of CPI-hepatitis and highlight CCR2 inhibition as a novel therapeutic target.

Detection of senescence using machine learning algorithms based on nuclear features.

Cellular senescence is a stress response with broad pathophysiological implications. Senotherapies can induce senescence to treat cancer or eliminate senescent cells to ameliorate ageing and age-related pathologies. However, the success of senotherapies is limited by the lack of reliable ways to identify senescence. Here, we use nuclear morphology features of senescent cells to devise machine-learning classifiers that accurately predict senescence induced by diverse stressors in different cell types and tissues. As a proof-of-principle, we use these senescence classifiers to characterise senolytics and to screen for drugs that selectively induce senescence in cancer cells but not normal cells. Moreover, a tissue senescence score served to assess the efficacy of senolytic drugs and identified senescence in mouse models of liver cancer initiation, ageing, and fibrosis, and in patients with fatty liver disease. Thus, senescence classifiers can help to detect pathophysiological senescence and to discover and validate potential senotherapies.

Integrated phenotyping of the anti-cancer immune response in HIV-associated hepatocellular carcinoma.

Background & Aims: HIV-seropositivity shortens survival in patients with hepatocellular carcinoma (HCC). Although risk factors for HCC including HCV infection can influence T cell phenotype, it is unknown whether HIV can influence functional characteristics of the T cell infiltrate. Methods: From the Liver Cancer in HIV biorepository, we derived 129 samples of transplanted (76%) or resected (20%) HCC in eight European and North American centres. We profiled intra- and peritumoural tissue to evaluate regulatory CD4+/FOXP3+ and immune-exhausted CD8+/PD1+ T cells in HIV+ (n = 66) and HIV- (n = 63) samples. We performed targeted transcriptomics and T-cell receptor sequencing in a restricted subset of samples evaluated in relationship with HIV status. We correlated immunopathologic features with patients' characteristics including markers of HIV infection. Results: Of the 66 HIV+ patients, 83% were HCV coinfected with an undetectable HIV viral load (51%) and a median blood CD4+ cell count of 430 cells/mm3 (range 15-908). Patients who were HIV+ were compared with HIV- controls with similar staging characteristics including Barcelona Clinic Liver Cancer (BCLC) stage A-B (86% vs. 83%, p = 0.16), <3 nodules (90% vs. 83%, p = 0.3) and median alpha-foetoprotein values (10.9 vs. 12.8 ng/ml, p = 0.72). HIV+ samples had higher PD-L1 expression rates in tumour tissue (51% vs. 8% p <0.0001) and displayed denser intratumoural CD4+/FOXP3+ (p <0.0001), CD8+/PD1+ (p <0.0001), with lower total peritumoural CD4+ (p <0.0001) and higher peritumoural CD8+/PD1+ (p <0.0001). Gene set analysis revealed HIV+ cases to have evidence of dysregulated adaptive and innate immunity. Tumour-infiltrating lymphocyte clonality was not influenced by HIV status. Conclusions: HIV-associated HCC harbours a profoundly immune-exhausted tumour microenvironment, warranting prospective testing of immunotherapy in this treatment-deprived patient population. Impact and Implications: Hepatocellular carcinoma is a non-AIDS defining malignancy characterised by poor survival. The programmed cell death (PD-1) pathway governs antiviral and anticancer immune exhaustion and is a therapeutic target in HCC. This study highlights how HIV infection is associated with significantly higher PD-L1 expression in HCC cells and in the surrounding microenvironment, leading to changes in cytotoxic and regulatory T cell function and dysregulation of proinflammatory pathways. Taken together, our results suggest dysfunctional T cell immunity as a mechanism of worse outcome in these patients and suggest clinical testing of checkpoint inhibitors in HIV-associated HCC.

Metabolic Profile Reflects Stages of Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease worldwide, with fibrosis stage being the main predictor for clinical outcomes. Here, we present the metabolic profile of NAFLD patients with regards to fibrosis progression. We included all consecutive new referrals for NAFLD services between 2011 and 2019. Demographic, anthropometric and clinical features and noninvasive markers of fibrosis were recorded at baseline and at follow-up. Significant and advanced fibrosis were defined using liver stiffness measurement (LSM) as LSM ≥ 8.1 kPa and LSM ≥ 12.1 kPa, respectively. Cirrhosis was diagnosed either histologically or clinically. Fast progressors of fibrosis were defined as those with delta stiffness ≥ 1.03 kPa/year (25% upper quartile of delta stiffness distribution). Targeted and untargeted metabolic profiles were analysed on fasting serum samples using Proton nuclear magnetic resonance (1H NMR). A total of 189 patients were included in the study; 111 (58.7%) underwent liver biopsy. Overall, 11.1% patients were diagnosed with cirrhosis, while 23.8% were classified as fast progressors. A combination of metabolites and lipoproteins could identify the fast fibrosis progressors (AUROC 0.788, 95% CI: 0.703-0.874, p < 0.001) and performed better than noninvasive markers. Specific metabolic profiles predict fibrosis progression in patients with nonalcoholic fatty liver disease. Algorithms combining metabolites and lipids could be integrated in the risk-stratification of these patients.

Regulation of immunological tolerance by the p53-inhibitor iASPP.

Maintenance of immunological homeostasis between tolerance and autoimmunity is essential for the prevention of human diseases ranging from autoimmune disease to cancer. Accumulating evidence suggests that p53 can mitigate phagocytosis-induced adjuvanticity thereby promoting immunological tolerance following programmed cell death. Here we identify Inhibitor of Apoptosis Stimulating p53 Protein (iASPP), a negative regulator of p53 transcriptional activity, as a regulator of immunological tolerance. iASPP-deficiency promoted lung adenocarcinoma and pancreatic cancer tumorigenesis, while iASPP-deficient mice were less susceptible to autoimmune disease. Immune responses to iASPP-deficient tumors exhibited hallmarks of immunosuppression, including activated regulatory T cells and exhausted CD8+ T cells. Interestingly, iASPP-deficient tumor cells and tumor-infiltrating myeloid cells, CD4+, and γδ T cells expressed elevated levels of PD-1H, a recently identified transcriptional target of p53 that promotes tolerogenic phagocytosis. Identification of an iASPP/p53 axis of immune homeostasis provides a therapeutic opportunity for both autoimmune disease and cancer.

Pembrolizumab-Induced Pancreatic Exocrine Insufficiency Complicated by Severe Hepatic Steatosis.

Anti-programmed death receptor-1 (anti-PD-1) monoclonal antibodies (mAbs) are used to treat an increasing range of cancers. However, the distinct toxicity profile of immune-related adverse events (irAEs) is a frequent drawback of their clinical application. Among the more common irAEs are hepatitis and colitis, which are diagnosed and graded in patients based on elevated serum liver enzyme levels and increased stool frequency, respectively, and both of which often require treatment with high-dose corticosteroids. Herein, we describe the case of a patient who developed severe transaminase elevation and diarrhoea due to an unusual irAE, which was successfully treated without corticosteroids.

Quality standards for the management of non-alcoholic fatty liver disease (NAFLD): consensus recommendations from the British Association for the Study of the Liver and British Society of Gastroenterology NAFLD Special Interest Group.

Non-alcoholic fatty liver disease (NAFLD) is common, affecting approximately 25% of the general population. The evidence base for the investigation and management of NAFLD is large and growing, but there is currently little practical guidance to support development of services and delivery of care. To address this, we produced a series of evidence-based quality standard recommendations for the management of NAFLD, with the aim of improving patient care. A multidisciplinary group of experts from the British Association for the Study of the Liver and British Society of Gastroenterology NAFLD Special Interest Group produced the recommendations, which cover: management of people with, or at risk of, NAFLD before the gastroenterology or liver clinic; assessment and investigations in secondary care; and management in secondary care. The quality of evidence for each recommendation was evaluated by the Grading of Recommendation Assessment, Development and Evaluation tool. An anonymous modified Delphi voting process was conducted individually by each member of the group to assess the level of agreement with each statement. Statements were included when agreement was 80% or greater. From the final list of statements, a smaller number of auditable key performance indicators were selected to allow services to benchmark their practice. It is hoped that services will review their practice against our recommendations and key performance indicators and institute service development where needed to improve the care of patients with NAFLD.

Predictive biomarkers of response to immune checkpoint inhibitors in hepatocellular carcinoma.

INTRODUCTION: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and fourth-leading cause of cancer death. While drug discovery to improve disease survival was historically poor, there is now evidence of significant potential for immune checkpoint inhibitors (ICPIs) in treatment of the disease, and indeed such drug approvals are beginning to emerge. AREAS COVERED: HCC typically arises in the context of cirrhosis and chronic liver disease (CLD), and HCC exhibits significant biological heterogeneity, in part reflecting the broad range of etiologies of CLD. Different classes and combinations of ICPI-based therapy exist, but not all patients will respond and predictive biomarkers are not yet available to guide clinician decision-making, unlike some other cancer types. In this review, we discuss the emerging biomarkers for ICPI sensitivity in HCC, including tumor genomic features, perturbation of the gut microbiome, and systemic inflammatory markers. EXPERT OPINION: Additional profiling studies are required to appreciate existing trends with clinical outcome and to further drive clinical studies in disease stratification by response. This will only be possible within collaborative and international efforts, especially regarding biopsy collection. A close collaboration between basic scientists and clinicians will be the key to shape the next future of HCC biomarker research.

Holistic Characterization of a Salmonella Typhimurium Infection Model Using Integrated Molecular Imaging.

A more complete and holistic view on host-microbe interactions is needed to understand the physiological and cellular barriers that affect the efficacy of drug treatments and allow the discovery and development of new therapeutics. Here, we developed a multimodal imaging approach combining histopathology with mass spectrometry imaging (MSI) and same section imaging mass cytometry (IMC) to study the effects of Salmonella Typhimurium infection in the liver of a mouse model using the S. Typhimurium strains SL3261 and SL1344. This approach enables correlation of tissue morphology and specific cell phenotypes with molecular images of tissue metabolism. IMC revealed a marked increase in immune cell markers and localization in immune aggregates in infected tissues. A correlative computational method (network analysis) was deployed to find metabolic features associated with infection and revealed metabolic clusters of acetyl carnitines, as well as phosphatidylcholine and phosphatidylethanolamine plasmalogen species, which could be associated with pro-inflammatory immune cell types. By developing an IMC marker for the detection of Salmonella LPS, we were further able to identify and characterize those cell types which contained S. Typhimurium.

Trans-arterial chemoembolization as a loco-regional inducer of immunogenic cell death in hepatocellular carcinoma: implications for immunotherapy.

BACKGROUND: Modulation of adaptive immunity may underscore the efficacy of trans-arterial chemoembolization (TACE). We evaluated the influence of TACE on T-cell function by phenotypic lymphocyte characterization in samples of patients undergoing surgery with (T+) or without (T-) prior-TACE treatment. METHODS: We profiled intratumoral (IT), peritumoral (PT) and non-tumoral (NT) background tissue to evaluate regulatory CD4+/FOXP3+ (T-reg) and immune-exhausted CD8+/PD-1+ T-cells across T+ (n=58) and T- (n=61). We performed targeted transcriptomics and T-cell receptor sequencing in a restricted subset of samples (n=24) evaluated in relationship with the expression of actionable drivers of anti-cancer immunity including PD-L1, indoleamine 2,3 dehydrogenase (IDO-1), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), Lag-3, Tim-3 and CD163. RESULTS: We analyzed 119 patients resected (n=25, 21%) or transplanted (n=94, 79%) for Child-Pugh A (n=65, 55%) and Barcelona Clinic Liver Cancer stage A (n=92, 77%) hepatocellular carcinoma. T+ samples displayed lower IT CD4+/FOXP3+ (p=0.006), CD8+ (p=0.002) and CD8+/PD-1+ and NT CD8+/PD-1+ (p<0.001) compared with T-. Lower IT (p=0.005) and NT CD4+/FOXP3+ (p=0.03) predicted for improved recurrence-free survival. In a subset of samples (n=24), transcriptomic analysis revealed upregulation of a pro-inflammatory response in T+. T+ samples were enriched for IRF2 expression (p=0.01), an interferon-regulated transcription factor implicated in cancer immune-evasion. T-cell clonality and expression of PD-L1, IDO-1, CTLA-4, Lag-3, Tim-3 and CD163 was similar in T+ versus T-. CONCLUSIONS: TACE is associated with lower IT density of immune-exhausted effector cytotoxic and T-regs, with significant upregulation of pro-inflammatory pathways. This highlights the pleiotropic effects of TACE in modulating the tumor microenvironment and strengthens the rationale for developing immunotherapy alongside TACE.

Severe Immune Checkpoint Inhibitor Hepatitis in KRAS G12C-Mutant NSCLC Potentially Triggered by Sotorasib: Case Report.

Sotorasib is a first-in-class small molecule that irreversibly inhibits KRAS G12C, locking it in an inactive state, inhibiting oncogenic signaling, and inducing a proinflammatory microenvironment. Here, we report the first case of life-threatening hepatitis in a patient with NSCLC shortly after commencing sotorasib, in which biopsy result was consistent with checkpoint inhibitor (CPI) immune-related adverse event, implicating sotorasib as being able to trigger CPI immune hepatitis. Given the large proportion of patients potentially treatable with sequential sotorasib after CPI, coupled with limited trial data, sotorasib-triggered CPI immune-related hepatitis should be considered in patients with sotorasib hepatotoxicity.

Phenotypic Characteristics of the Tumour Microenvironment in Primary and Secondary Hepatocellular Carcinoma.

(1) Background: The intra-tumoural heterogeneity (ITH) of hepatocellular carcinoma (HCC) and its microenvironment (TME) across primary and secondary disease is poorly characterised. (2) Methods: Intra-tumoural (IT) and peri-tumoural (PT) staining of matched primary and secondary samples was conducted to evaluate the distribution of CD4+/FOXP3+ and CD8+/PD1+ T-cells. Samples underwent PD-L1/2 immunostaining, tumour mutational burden (TMB) evaluation, and high-resolution T-cell receptor (TCR) sequencing to derive T-cell clonality and targeted transcriptomics. (3) Results: We analysed 24 samples from matched primary (n = 11) and secondary (n = 13; 5 synchronous, 6 metachronous) deposits, 11 being extrahepatic (84.6%). IT CD8+ density was lower than PT in both primary (p = 0.005) and secondary deposits (p = 0.01), consistent with immune exclusion. PD-L1+ tumours displayed higher IT and PT CD8+/PD1+ cell density compared to PD-L1- (p < 0.05), and primary IT infiltrate was enriched in CD4+/FOXP3+ cells, compared to PT regions (p = 0.004). TCR-sequencing demonstrated enrichment of the top T-cell clonotype in secondary versus primary HCC (p = 0.02), without differences in overall productive clonality (p = 0.35). TMB was similar across primary versus secondary HCC (p = 0.95). While directed gene set analysis demonstrated the uniformity of transcriptional signatures of individual immune cell types, secondary deposits demonstrated higher COLEC12 (p = 0.004), CCL26 (p = 0.02), CD1E (p = 0.02) and CD36 (p = 0.03) expression with downregulation of CXCL1 (p = 0.03), suggesting differential regulation of innate immunity. (4) Conclusion: Immune exclusion is a defining feature of the HCC TME. Despite evidence of homogeneity in somatic TMB, secondary HCC is characterised by the expansion of a distinct T-cell clonotype and differential regulation of innate immune pathways.

Activation and transcriptional profile of monocytes and CD8+ T cells are altered in checkpoint inhibitor-related hepatitis.

BACKGROUND & AIMS: Checkpoint inhibitor-related hepatitis (CPI-Hep) is an emerging clinical challenge. We aimed to gain insights into the immunopathology of CPI-Hep by comprehensively characterising myeloid and lymphoid subsets. METHODS: CPI-treated patients with or without related hepatitis (CPI-Hep; n = 22 and CPI-noHep; n = 7) were recruited. Phenotypic and transcriptional profiling of peripheral immune subsets was performed and compared with 19 healthy controls (HCs). In vitro monocyte-derived macrophages (MoMFs) were assessed for activation and cytokine production. CD163, CCR2, CD68, CD3, CD8 and granzyme B expression was assessed using immunohistochemistry/immunofluorescence (n = 4). RESULTS: A significant total monocyte depletion was observed in CPI-Hep compared with HCs (p = 0.04), along with a proportionate increase in the classical monocyte population (p = 0.0002) and significant upregulation of CCR2, CD163 and downregulation of CCR7. Soluble CD163 levels were significantly elevated in CPI-Hep compared with HCs (p <0.0001). In vitro MoMFs from CPI-Hep showed enhanced production of pro-inflammatory cytokines. CD8+ T cells demonstrated increased perforin, granzyme B, ICOS and HLA-DR expression in CPI-Hep. Transcriptional profiling indicated the presence of activated monocyte and enhanced effector CD8+ T cell populations in CPI-Hep. Immunohistochemistry demonstrated co-localisation of CD8+/granzyme B+ T cells with CD68+CCR2+/CD68+CD163+ macrophages in CPI-Hep liver tissue. CONCLUSIONS: CPI-Hep is associated with activation of peripheral monocytes and an enhanced cytotoxic, effector CD8+ T cell phenotype. These changes were reflected by liver inflammation composed of CD163+/CCR2+ macrophages and CD8+ T cells. LAY SUMMARY: Some patients who receive immunotherapy for cancer develop liver inflammation, which requires cessation of cancer treatment. Herein, we describe ways in which the white blood cells of patients who develop liver inflammation differ from those of patients who receive the same immunotherapy but do not experience liver-related side effects. Targeting some of the pathways we identify may help to prevent or manage this side effect and facilitate cancer treatment.

Liver function tests and metabolic-associated fatty liver disease: Changes in upper normal limits, does it really matter?

BACKGROUND: Metabolic-associated fatty liver disease (MAFLD) is the commonest cause of abnormal liver function tests (LFTs). Current upper normal of limit (UNL) of LFTs was derived from a "healthy" population, where undiagnosed MAFLD and viral hepatitis might be suspected. AIM: To evaluated potential implications of changes in UNL of alanine aminotransferase (ALT) in MAFLD. METHODS: We retrospectively assessed consecutive first referrals with a diagnosis of MAFLD from 2010 to 2017. The conventional UNL of ALT was 45 IU/L for men and 34 IU/L for women, while a low UNL of ALT was 30 IU/L for men and 19 IU/L for women. The UNL of aspartate aminotransferase (AST) was 40 IU/L. RESULTS: Total 436 patients were enrolled; of these, 288 underwent liver biopsy. Setting a lower UNL reduced the percentage of those with significant disease despite normal ALT; specifically, patients with advanced fibrosis (F ≥ F3) or definite "metabolic-associated steato-hepatitis (MASH)" (NAS ≥ 5) within normal ALT decreased from 10% to 1% and from 28% to 4% respectively. However, the proportion of those with elevated ALT and no evidence of advanced fibrosis or "definite MASH" increased from 39% to 47% and from 3% to 19%. Overall, LFTs performed poorly in distinguishing "definite MASH" from simple steatosis (receiver operating characteristic areas under the curves 0.59 for ALT and 0.55 for AST). CONCLUSION: Liver function tests might both under- and overestimate MASH-related liver disease. Reducing the UNL might not be beneficial and imply an increase in healthcare burden. Risk stratification in MAFLD should rely on a combination of risk factors, not on LFTs alone.

Qualification of tumour mutational burden by targeted next-generation sequencing as a biomarker in hepatocellular carcinoma.

BACKGROUND & AIMS: Tumour mutational burden (TMB) predicts improved response and survival to immunotherapy. In this pilot study, we optimized targeted next-generation sequencing (tNGS) to estimate TMB in hepatocellular carcinoma (HCC). METHODS: We sequenced 48 non-paired samples (21 fresh-frozen [FF] and 27 paraffin-embedded [FFPE]), among which 11 FFPE samples were pretreated with uracil-DNA glycosylase (UDG). Thirty samples satisfied post-sequencing quality control. High/low TMB was defined by median number of mutations/Mb (Mut/Mb), across different minimum allele frequency (MAF) thresholds (≥0.05, ≥0.1 and ≥0.2). RESULTS: Eligible patients (n = 29) were cirrhotic (84%) with TNM stage I-II HCC (75%). FFPE samples had higher TMB (median 958.39 vs 2.51 Mut/Mb, P < .0001), estimated deamination counts (median 1335.50 vs 0, P < .0001) and C > T transitions at CpG sites (median 60.3% vs 9.1%, P = .002) compared to FF. UDG-treated samples had lower TMB (median 4019.92 vs 353 Mut/Mb, P = .041) and deamination counts (median 6393.5 vs 328.5, P = .041) vs untreated FFPE. At 0.2 MAF threshold with UDG treatment, median TMB was 5.48 (range 1.68-16.07) and did not correlate with salient pathologic features of HCC, including survival. CONCLUSION: While tNGS on fresh HCC samples appears to be the optimal source of tumour DNA, the low median TMB values observed may limit the role of TMB as a predictor of response to immunotherapy in HCC.

PD-1 blockade improves Kupffer cell bacterial clearance in acute liver injury.

Patients with acute liver failure (ALF) have systemic innate immune suppression and increased susceptibility to infections. Programmed cell death 1 (PD-1) expression by macrophages has been associated with immune suppression during sepsis and cancer. We therefore examined the role of the programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) pathway in regulating Kupffer cell (KC) inflammatory and antimicrobial responses in acetaminophen-induced (APAP-induced) acute liver injury. Using intravital imaging and flow cytometry, we found impaired KC bacterial clearance and systemic bacterial dissemination in mice with liver injury. We detected increased PD-1 and PD-L1 expression in KCs and lymphocyte subsets, respectively, during injury resolution. Gene expression profiling of PD-1+ KCs revealed an immune-suppressive profile and reduced pathogen responses. Compared with WT mice, PD-1-deficient mice and anti-PD-1-treated mice with liver injury showed improved KC bacterial clearance, a reduced tissue bacterial load, and protection from sepsis. Blood samples from patients with ALF revealed enhanced PD-1 and PD-L1 expression by monocytes and lymphocytes, respectively, and that soluble PD-L1 plasma levels could predict outcomes and sepsis. PD-1 in vitro blockade restored monocyte functionality. Our study describes a role for the PD-1/PD-L1 axis in suppressing KC and monocyte antimicrobial responses after liver injury and identifies anti-PD-1 immunotherapy as a strategy to reduce infection susceptibility in ALF.

Tumour subregion analysis of colorectal liver metastases using semi-automated clustering based on DCE-MRI: Comparison with histological subregions and impact on pharmacokinetic parameter analysis.

PURPOSE: To use a novel segmentation methodology based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to define tumour subregions of liver metastases from colorectal cancer (CRC), to compare these with histology, and to use these to compare extracted pharmacokinetic (PK) parameters between tumour subregions. MATERIALS AND METHODS: This ethically-approved prospective study recruited patients with CRC and ≥1 hepatic metastases scheduled for hepatic resection. Patients underwent DCE-MRI pre-metastasectomy. Histological sections of resection specimens were spatially matched to DCE-MRI acquisitions and used to define histological subregions of viable and non-viable tumour. A semi-automated voxel-wise image segmentation algorithm based on the DCE-MRI contrast-uptake curves was used to define imaging subregions of viable and non-viable tumour. Overlap of histologically-defined and imaging subregions was compared using the Dice similarity coefficient (DSC). DCE-MRI PK parameters were compared for the whole tumour and histology-defined and imaging-derived subregions. RESULTS: Fourteen patients were included in the analysis. Direct histological comparison with imaging was possible in nine patients. Mean DSC for viable tumour subregions defined by imaging and histology was 0.738 (range 0.540-0.930). There were significant differences between Ktrans and kep for viable and non-viable subregions (p < 0.001) and between whole lesions and viable subregions (p < 0.001). CONCLUSION: We demonstrate good concordance of viable tumour segmentation based on pre-operative DCE-MRI with a post-operative histological gold-standard. This can be used to extract viable tumour-specific values from quantitative image analysis, and could improve treatment response assessment in clinical practice.

High-Throughput, Machine Learning-Based Quantification of Steatosis, Inflammation, Ballooning, and Fibrosis in Biopsies From Patients With Nonalcoholic Fatty Liver Disease.

BACKGROUND & AIMS: Liver biopsy is the reference standard for staging and grading nonalcoholic fatty liver disease (NAFLD), but histologic scoring systems are semiquantitative with marked interobserver and intraobserver variation. We used machine learning to develop fully automated software for quantification of steatosis, inflammation, ballooning, and fibrosis in biopsy specimens from patients with NAFLD and validated the technology in a separate group of patients. METHODS: We collected data from 246 consecutive patients with biopsy-proven NAFLD and followed up in London from January 2010 through December 2016. Biopsy specimens from the first 100 patients were used to derive the algorithm and biopsy specimens from the following 146 were used to validate it. Biopsy specimens were scored independently by pathologists using the Nonalcoholic Steatohepatitis Clinical Research Network criteria and digitalized. Areas of steatosis, inflammation, ballooning, and fibrosis were annotated on biopsy specimens by 2 hepatobiliary histopathologists to facilitate machine learning. Images of biopsies from the derivation and validation sets then were analyzed by the algorithm to compute percentages of fat, inflammation, ballooning, and fibrosis, as well as the collagen proportionate area, and compared with findings from pathologists' manual annotations and conventional scoring systems. RESULTS: In the derivation group, results from manual annotation and the software had an interclass correlation coefficient (ICC) of 0.97 for steatosis (95% CI, 0.95-0.99; P < .001); ICC of 0.96 for inflammation (95% CI, 0.9-0.98; P < .001); ICC of 0.94 for ballooning (95% CI, 0.87-0.98; P < .001); and ICC of 0.92 for fibrosis (95% CI, 0.88-0.96; P = .001). Percentages of fat, inflammation, ballooning, and the collagen proportionate area from the derivation group were confirmed in the validation cohort. The software identified histologic features of NAFLD with levels of interobserver and intraobserver agreement ranging from 0.95 to 0.99; this value was higher than that of semiquantitative scoring systems, which ranged from 0.58 to 0.88. In a subgroup of paired liver biopsy specimens, quantitative analysis was more sensitive in detecting differences compared with the nonalcoholic steatohepatitis Clinical Research Network scoring system. CONCLUSIONS: We used machine learning to develop software to rapidly and objectively analyze liver biopsy specimens for histologic features of NAFLD. The results from the software correlate with those from histopathologists, with high levels of interobserver and intraobserver agreement. Findings were validated in a separate group of patients. This tool might be used for objective assessment of response to therapy for NAFLD in practice and clinical trials.