Greater Transplant-Free Survival in Patients Receiving Obeticholic Acid for Primary Biliary Cholangitis in a Clinical Trial Setting Compared to Real-World External Controls

BACKGROUND & AIMS

The Primary Biliary Cholangitis (PBC) Obeticholic Acid (OCA) International Study of Efficacy (POISE) randomized, double-blind, placebo-controlled trial demonstrated that OCA reduced biomarkers associated with adverse clinical outcomes (ie, alkaline phosphatase, bilirubin, aspartate aminotransferase, and alanine aminotransferase) in patients with PBC. The objective of this study was to evaluate time to first occurrence of liver transplantation or death in patients with OCA in the POISE trial and open-label extension vs comparable non-OCA-treated external controls.

METHODS

Propensity scores were generated for external control patients meeting POISE eligibility criteria from 2 registry studies (Global PBC and UK-PBC) using an index date selected randomly between the first and last date (inclusive) on which eligibility criteria were met. Cox proportional hazards models weighted by inverse probability of treatment assessed time to death or liver transplantation. Additional analyses (Global PBC only) added hepatic decompensation to the composite end point and assessed efficacy in patients with or without cirrhosis.

RESULTS

During the 6-year follow-up, there were 5 deaths or liver transplantations in 209 subjects in the POISE cohort (2.4%), 135 of 1381 patients in the Global PBC control (10.0%), and 281 of 2135 patients in the UK-PBC control (13.2%). The hazard ratios (HRs) for the primary outcome were 0.29 (95% CI, 0.10-0.83) for POISE vs Global PBC and 0.30 (95% CI, 0.12-0.75) for POISE vs UK-PBC. In the Global PBC study, HR was 0.20 (95% CI, 0.03-1.22) for patients with cirrhosis and 0.31 (95% CI, 0.09-1.04) for those without cirrhosis; HR was 0.42 (95% CI, 0.21-0.85) including hepatic decompensation.

CONCLUSIONS

Patients treated with OCA in a trial setting had significantly greater transplant-free survival than comparable external control patients.

Epithelial cell specificity and apotope recognition by serum autoantibodies in primary biliary cirrhosis

A major enigma of primary biliary cirrhosis (PBC) is the selective targeting of biliary cells. Our laboratory has reported that after apoptosis, human intrahepatic biliary epithelial cells (HiBECs) translocate the E2 subunit of the pyruvate dehydrogenase complex immunologically intact into apoptotic bodies, forming an apotope. However, the cell type and specificity of this reaction has not been fully defined. To address this issue, we investigated whether the E2 subunit of the pyruvate dehydrogenase complex, the E2 subunit of the branched chain 2-oxo acid dehydrogenase complex, the E2 subunit of the oxo-glutarate dehydrogenase complex, four additional inner mitochondrial enzymes, and four nuclear antigens remain immunologically intact with respect to postapoptotic translocation in HiBECs and three additional control epithelial cells. We report that all three 2-oxo acid dehydrogenase enzymes share the ability to remain intact within the apotope of HiBECs. Interestingly, the E2 subunit of the branched chain 2-oxo acid dehydrogenase complex also remained intact in the other cell types tested. We extended the data, using sera from 95 AMA-positive and 19 AMA-negative patients with PBC and 76 controls, by testing for reactivity against the seven mitochondrial proteins studied herein and also the ability of AMA-negative sera to react with HiBEC apotopes. Sera from 3 of 95 AMA-positive sera, but none of the controls, reacted with 2,4-dienoyl coenzyme A reductase 1, an enzyme also present intact only in the HiBEC apotope, but which has not been previously associated with any autoimmune disease. Finally, the specificity of HiBEC apotope reactivity was confined to AMA-positive sera.

CONCLUSION

We submit that the biliary specificity of PBC is secondary to the unique processes of biliary apoptosis.

Increased loss of the Y chromosome in peripheral blood cells in male patients with autoimmune thyroiditis

Multiple mechanisms have been proposed to explain the peculiar distribution of autoimmune thyroiditis (AIT) among women and men. Most attention has been focused on the detection of the role of estrogens and the X chromosome. Specifically, a potential role for X haploinsufficiency has been proposed in the female patient population and an association with the disease has been confirmed. Our knowledge of the etiopathogenesis of autoimmunity in male patients remains, however, limited. Next to the possible role of androgens and their imbalances, the Y chromosome appears as a potential candidate for influence of the immune function in men. Herein we analyzed a population of male patients with AIT (n=31) and healthy controls (n=88) to define a potential association of disease and the loss of the Y chromosome. Y chromosome loss increases in AIT compared to unaffected subjects; these phenomenon increases with aging as expected, however, the degree of loss is significantly increased in the patient population compared to the healthy controls. We were, thus, able to confirm the existence of an analogous mechanism in the male population to previously identified X haploinsufficiency in female patients with AIT. We propose that this commonality might represent a relevant feature in the etiopathogenesis of AIT that should be further investigated.

Antimitochondrial antibody heterogeneity and the xenobiotic etiology of primary biliary cirrhosis

Antimitochondrial antibodies (AMAs) directed against the lipoyl domain of the E2 subunit of pyruvate dehydrogenase (PDC-E2) are detected in 95% of patients with primary biliary cirrhosis (PBC) and are present before the onset of clinical disease. The recent demonstration that AMAs recognize xenobiotic modified PDC-E2 with higher titers than native PDC-E2 raises the possibility that the earliest events involved in loss of tolerance are related to xenobiotic modification. We hypothesized that reactivity to such xenobiotics would be predominantly immunoglobulin M (IgM) and using sera from a large cohort of PBC patients and controls (n = 516), we examined in detail sera reactivity against either 6,8-bis(acetylthio) octanoic acid (SAc)-conjugated bovine serum albumin (BSA), recombinant PDC-E2 (rPDC-E2) or BSA alone. Further, we also defined the relative specificity to the SAc moiety using inhibition enzyme-linked immunosorbent assay (ELISA); SAc conjugate and rPDC-E2-specific affinity-purified antibodies were also examined for antigen specificity, isotype, and crossreactivity. Reactivity to SAc conjugates is predominantly IgM; such reactivity reflects a footprint of previous xenobiotic exposure. Indeed, this observation is supported by both direct binding, crossreactivity, and inhibition studies. In both early and late-stage PBC, the predominant Ig isotype to SAc is IgM, with titers higher with advanced stage disease. We also note that there was a higher level of IgM reactivity to SAc than to rPDC-E2 in early-stage versus late-stage PBC. Interestingly, this finding is particularly significant in light of the structural similarity between SAc and the reduced form of lipoic acid, a step which is similar to the normal physiological oxidation of lipoic acid.

CONCLUSION

Specific modifications of the disulfide bond within the lipoic-acid-conjugated PDC-E2 moiety, i.e., by an electrophilic agent renders PDC-E2 immunogenic in a genetically susceptible host.

X chromosome gene methylation in peripheral lymphocytes from monozygotic twins discordant for scleroderma

Scleroderma (SSc) is a rare connective tissue disease characterized by fibrosis, microvasculopathy and autoimmune features. The role of genetics is limited in SSc, as suggested by similar concordance rates in monozygotic and dizygotic twin pairs, while environmental factors may act through epigenetic changes, as demonstrated for specific genes. Further, sex chromosome changes have been reported in SSc and may explain the female preponderance. In the present study we compared the methylation profile of all X chromosome genes in peripheral blood mononuclear cells from monozygotic twins discordant (n=7) and concordant (n=1) for SSc. Methylated DNA immunoprecipitations from each discordant twin pair were hybridized to a custom-designed array included 998 sites encompassing promoters of all X chromosome genes and randomly chosen autosomal genes. Biostatistical tools identified sites with an elevated probability to be consistently hypermethylated (n=18) or hypomethylated (n=25) in affected twins. Identified genes include transcription factors (ARX, HSFX1, ZBED1, ZNF41) and surface antigens (IL1RAPL2, PGRMC1), and pathway analysis suggests their involvement in cell proliferation (PGK1, SMS, UTP14A, SSR4), apoptosis (MTM1), inflammation (ARAF) and oxidative stress (ENOX2). In conclusion, we propose that X chromosome genes with different methylation profiles in monozygotic twin pairs may constitute candidates for SSc susceptibility.

Innate immunity and primary biliary cirrhosis

There has been a rapid growth in our understanding of the molecular bases of primary biliary cirrhosis (PBC). These efforts were initiated when the immunodominant mitochondrial autoantigen was cloned and sequenced. Using the recombinant cloned antigen as a tool, research has focused on the effector mechanisms of disease and the uniqueness of the primary target tissue, the intrahepatic bile ducts. Most recently, there have been experimental data suggesting that innate immunity changes may be critical to the initiation and perpetuation of the autoimmune injury, as in the case of the enhanced response of monocytes and memory B cells to infectious stimulation and environmental mimics. These observations are important as they help fill in the many gaps which remain on the most difficult subject of autoimmunity, etiology. Indeed, based on the available data, several experimental models of PBC have been developed. These models illustrate and suggest that PBC can be initiated by several mechanisms, all of which lead to loss of tolerance to the mitochondrial antigens. However, once this adaptive response develops, it appears that much of the subsequent pathology is exacerbated by innate responses. We suggest that future therapeutic efforts in PBC will depend heavily on understanding the nature of this innate immune responses and methodology to blunt their cytotoxicity.

Pathway-based analysis of primary biliary cirrhosis genome-wide association studies

Genome-wide association studies (GWAS) have successfully identified several loci associated with primary biliary cirrhosis (PBC) risk. Pathway analysis complements conventional GWAS analysis. We applied the recently developed linear combination test for pathways to datasets drawn from independent PBC GWAS in Italian and Canadian subjects. Of the Kyoto Encyclopedia of Genes and Genomes and BioCarta pathways tested, 25 pathways in the Italian dataset (449 cases, 940 controls) and 26 pathways in the Canadian dataset (530 cases, 398 controls) were associated with PBC susceptibility (P<0.05). After correcting for multiple comparisons, only the eight most significant pathways in the Italian dataset had FDR <0.25 with tumor necrosis factor/stress-related signaling emerging as the top pathway (P=7.38 × 10⁻⁴, FDR=0.18). Two pathways, phosphatidylinositol signaling and hedgehog signaling, were replicated in both datasets (P<0.05), and subjected to two additional complementary pathway tests. Both pathway signals remained significant in the Italian dataset on modified gene set enrichment analysis (P<0.05). In both GWAS, variants nominally associated with PBC were significantly overrepresented in the phosphatidylinositol pathway (Fisher exact P<0.05). These results point to established and novel pathway-level associations with inherited predisposition to PBC that, on further independent replication and functional validation, may provide fresh insights into PBC etiology.

COVID-19 Digestive System Involvement and Clinical Outcomes in a Large Academic Hospital in Milan, Italy

Since February 2020, the COVID-19 pandemic has spread to Italy affecting more than 100,000 people. Several studies have reported a high prevalence of gastrointestinal (GI) symptoms, and investigated their potential association with clinical outcomes.1 The timing, clinical significance, and possible impact on viral spread of GI symptoms presentation have not been fully elucidated. Elevation of liver function tests and other laboratory values has also been reported; however, their prognostic significance has not been clearly established.2.

Predictors of hepatocellular carcinoma in HCV cirrhotic patients treated with direct acting antivirals

BACKGROUND

Despite the dramatic improvement in viral eradication rates that has been reached with direct antiviral agents (DAAs), the real benefit of viral eradication after DAAs on hepatocellular carcinoma (HCC) development is still controversial.

AIM

To prospectively assess the risk of HCC occurrence and early recurrence in a large cohort of DAA-treated HCV-cirrhotic patients and to identify potential predictors of HCC development.

METHODS

We analyzed data prospectively collected from 1927 consecutive HCV-infected cirrhotic patients treated with DAA from January to December 2015 in 10 tertiary liver centers in Italy and followed-up for one year after therapy. 161 patients had a previous HCC.

RESULTS

38/161 subjects developed tumor recurrence during the follow-up (recurrence rate = 24.8 per 100-year), patients with SVR had a significantly lower rate of recurrence. Lack of SVR and alpha-fetoprotein (AFP) were independent predictors of HCC recurrence. 50/1766 patients without a previous HCC history developed HCC during follow-up (incidence rate = 2.4 per 100-year). Lack of SVR was the strongest predictor of HCC development. Furthermore, patients with SVR and no stigmata of portal hypertension have a lower incidence rate of HCC (1.0 per 100-year).

CONCLUSIONS

SVR is associated with a significant decrease of recurrent or de novo HCC. Baseline AFP and signs of portal hypertension can help to stratify the risk of HCC.

Melatonin exerts by an autocrine loop antiproliferative effects in cholangiocarcinoma: its synthesis is reduced favoring cholangiocarcinoma growth

Cholangiocarcinoma (CCA) is a devastating biliary cancer. Melatonin is synthesized in the pineal gland and peripheral organs from serotonin by two enzymes, serotonin N-acetyltransferase (AANAT) and acetylserotonin O-methyltransferase (ASMT). Cholangiocytes secrete neuroendocrine factors, including serotonin-regulating CCA growth by autocrine mechanisms. Melatonin exerts its effects by interaction with melatonin receptor type 1A/1B (MT1/MT2) receptors. We propose that 1) in CCA, there is decreased expression of AANAT and ASMT and secretion of melatonin, changes that stimulate CCA growth; and 2) in vitro overexpression of AANAT decreases CCA growth. We evaluated the 1) expression of AANAT, ASMT, melatonin, and MT1/MT2 in human nonmalignant and CCA lines and control and CCA biopsy samples; 2) melatonin levels in nonmalignant and CCA lines, and bile and serum from controls and patients with intrahepatic CCA; 3) effect of melatonin on the growth and expression of AANAT/ASMT and MT1/MT2 in CCA lines implanted into nude mice; and 4) effect of AANAT overexpression on the proliferation, apoptosis, and expression of MT1/MT2 in Mz-ChA-1 cells. The expression of AANAT, ASMT, and melatonin decreased, whereas MT1/MT2 expression increased in CCA lines and biopsy samples. Melatonin secretion decreased in the supernatant of CCA lines and bile of CCA patients. Melatonin decreased xenograft CCA tumor growth in nude mice by increased AANAT/ASMT and melatonin, along with reduced MT1/MT2 expression. Overexpression of AANAT in Mz-ChA-1 cells inhibited proliferation and MT1/MT2 expression and increased apoptosis. There is dysregulation of the AANAT/ASMT/melatonin → melatonin receptor axis in CCA, which inhibited melatonin secretion and subsequently enhanced CCA growth.

HLA class II antigens associated with lupus nephritis in Italian SLE patients

Human leukocyte antigen DR2 (HLA-DR2), namely the allelic variant HLA-DR15, have been associated with lupus nephritis (LN) in Caucasians. The study investigated the relationships between HLA class II alleles and lupus nephritis in Italian patients. Two hundred forty-four patients fulfilling the American Rheumatism Association criteria for systemic lupus erythematosus (SLE) were typed for HLA-DRB1*, -DQA1*, -DQB1*, and -DPB1* alleles by polymerase chain reaction-sequence-specific oligonucleotide and polymears chain reaction-single-strand polymorphism; 71 patients had renal damage assessed by renal biopsy. Glomerulonephritis was classified using WHO criteria. Significance was tested by X(2) on 2x2 tables. HLA-DQA1*0101 was strongly associated with LN (OR = 2.72 [1.43-5.19]; p = 0.002), whereas HLA-DRB1*1501 was only marginally associated (OR = 1.94 [0.88-4.26]; p = not significant). HLA-DQA1*0102 demonstrated a significant protective effect (OR = 0.31 [0.14-0.86]; p = 0.002). On analyzing the distribution of HLA-DRB1*1501 bearing haplotypes in our SLE patients we found that the HLA-DRB1*1501 greatly enhanced the risk of developing LN conferred by the DQA1*0101 allele (OR = 65.96 [9.35-1326.25]), whereas DQA1*0102 suppressed the nephritogenic effect of DRB1*1501. At renal biopsy, 80% of DRB1*15 positive patients were classified as having class IV LN with the remaining 20% having class III LN. The figures were 19% and 21%, respectively, among the HLA-DR15 negative patients. In the Italian population HLA-DQA and HLA-DR alleles interact in conferring susceptibility to or protection against lupus nephritis, the diffuse proliferative glomerulonephritis (i.e., the most severe form of nephritis) is associated with the HLA-DR15 bearing haplotypes.

Experimental liver models: From cell culture techniques to microfluidic organs-on-chip

The liver is one of the most studied organs of the human body owing to its central role in xenobiotic and drug metabolism. In recent decades, extensive research has aimed at developing in vitro liver models able to mimic liver functions to study pathophysiological clues in high-throughput and reproducible environments. Two-dimensional (2D) models have been widely used in screening potential toxic compounds but have failed to accurately reproduce the three-dimensionality (3D) of the liver milieu. To overcome these limitations, improved 3D culture techniques have been developed to recapitulate the hepatic native microenvironment. These models focus on reproducing the liver architecture, representing both parenchymal and nonparenchymal cells, as well as cell interactions. More recently, Liver-on-Chip (LoC) models have been developed with the aim of providing physiological fluid flow and thus achieving essential hepatic functions. Given their unprecedented ability to recapitulate critical features of the liver cellular environments, LoC have been extensively adopted in pathophysiological modelling and currently represent a promising tool for tissue engineering and drug screening applications. In this review, we discuss the evolution of experimental liver models, from the ancient 2D hepatocyte models, widely used for liver toxicity screening, to 3D and LoC culture strategies adopted for mirroring a more physiological microenvironment for the study of liver diseases.

The immune milieu of cholangiocarcinoma: From molecular pathogenesis to precision medicine

Cholangiocarcinoma (CCA) is a deadly cancer of the biliary epithelium with limited therapeutic options. It is a heterogeneous group of cancer that could develop at any level from the biliary tree and is currently classified into intrahepatic, perihilar and distal based on its anatomical location. With incidence and mortality rates currently increasing, it is now the second most common type of primary liver cancer and represents up to 3% of all gastrointestinal malignancies. High-throughput genomics and epigenomics have greatly increased our understanding of CCA underlying biology, however its pathogenesis remains largely unknown. CCA is characterized by a highly desmoplastic microenvironment containing stromal cells, mainly cancer-associated fibroblasts, infiltrating tumor epithelium. Tumor microenvironment in CCA is a highly dynamic environment that, besides stromal and endothelial cells, encompass also an abundance of immune cells, of both the innate and adaptive immune system (including tumor-associated macrophages, neutrophils, natural killer cells, and T and B lymphocytes) and abundant proliferative factors. It is orchestrated by multiple soluble factors and signals, that eventually define a tumor growth-permissive microenvironment. Through complicate interactions with CCA cells, tumor microenvironment profoundly affects the proliferative and invasive abilities of epithelial cancer cells and plays an important role in accelerating neovascularization and preventing apoptosis of neoplastic cells. In this review, we discuss recent developments regarding the characteristics of the tumor microenvironment, the role of each cellular population, and their multiarticulate interaction with the malignant population. Further we discuss innovative treatment approaches, including immunotherapy, and how identification of CCA secreted factors by both the stromal component and immune cell subsets are leading towards a precision medicine in CCA.

Genetic associations in Italian primary sclerosing cholangitis: heterogeneity across Europe defines a critical role for HLA-C

BACKGROUND & AIMS

The HLA complex on chromosome 6p21 is firmly established as a risk locus for primary sclerosing cholangitis (PSC). We aimed to exploit genetic differences between Northern Europe and Italy in an attempt to define a causative locus in this genetic region.

METHODS

Seventy-eight North-Italian PSC patients and 79 controls were included. We performed sequencing-based genotyping of HLA-C, HLA-B, and HLA-DRB1. The major histocompatibility chain-related A (MICA) transmembrane microsatellite was analysed using PCR fragment length determination. The tumour necrosis factor-alpha (TNF-alpha)-308G-->A polymorphism was genotyped with TaqMan. Allele frequencies were compared with Chi-square tests. Uncorrected p-values <0.05 were considered statistically significant when replicating findings in previous studies. The p-values of novel associations were corrected for multiple comparisons (Bonferroni).

RESULTS

The frequency of the strong inhibitory HLA-C2 killer-immunoglobulin receptor (KIR) ligand variant was significantly reduced in PSC vs. controls (0.39 vs. 0.58, p=0.0006). Consequently, HLA-C1 homozygosity was associated with an increased risk of PSC (OR 3.1; 95% CI 1.4-6.7, p=0.004). Importantly, there were no significant associations with the HLA-Bw4 KIR ligand variant, at the neighbouring MICA locus or with TNF-alpha-308G-->A. At HLA-DRB1, we confirmed positive and negative associations with DRB1*15 and DRB1*07, respectively, while there were no associations with the DRB1*03, *04 or *1301 alleles typically detected in PSC in Northern Europe.

CONCLUSIONS

The strong inhibitory of the KIR ligand HLA-C2 protects against PSC development in all populations hitherto studied. Further studies on the role of natural killer cells and T-lymphocytes expressing KIRs in PSC pathogenesis are warranted.

Real-world experience with obeticholic acid in patients with primary biliary cholangitis

BACKGROUND & AIMS

Obeticholic acid (OCA) is the second-line treatment approved for patients with primary biliary cholangitis (PBC) and an inadequate response or intolerance to ursodeoxycholic acid. We aimed to evaluate the effectiveness and safety of OCA under real-world conditions.

METHODS

Patients were recruited into the Italian PBC Registry, a multicentre, observational cohort study that monitors patients with PBC at national level. The primary endpoint was the biochemical response according to Poise criteria; the secondary endpoint was the biochemical response according to normal range criteria, defined as normal levels of bilirubin, alkaline phosphatase (ALP), and alanine aminotransferase (ALT) at 12 months. Safety and tolerability were also assessed.

RESULTS

We analysed 191 patients until at least 12 months of follow-up. Median age was 57 years, 94% female, 61 (32%) had cirrhosis, 28 (15%) had histologically proven overlap with autoimmune hepatitis (PBC-AIH). At 12 months, significant median reductions of ALP (-32.3%), ALT (-31.4%), and bilirubin (-11.2%) were observed. Response rates were 42.9% according to Poise criteria, and 11% by normal range criteria. Patients with cirrhosis had lower response than patients without cirrhosis (29.5% vs. 49.2%, p = 0.01), owing to a higher rate of OCA discontinuation (30% vs. 12%, p = 0.004), although with similar ALP reduction (29.4% vs. 34%, p = 0.53). Overlap PBC-AIH had a similar response to pure PBC (46.4% vs. 42.3%, p = 0.68), with higher ALT reduction at 6 months (-38% vs. -29%, p = 0.04). Thirty-three patients (17%) prematurely discontinued OCA because of adverse events, of whom 11 experienced serious adverse events. Treatment-induced pruritus was the leading cause of OCA discontinuation (67%).

CONCLUSIONS

Effectiveness and safety of OCA under real-world conditions mirror those in the Poise trial. Patients with cirrhosis had lower tolerability. Overlap PBC-AIH showed higher ALT reduction at 6 months compared with patients with pure PBC.

LAY SUMMARY

Obeticholic acid (OCA) was shown to be effective in more than one-third of patients not responding to ursodeoxycholic acid in a real-world context in Italy. Patients with cirrhosis had more side effects with OCA, and this led to suspension of the drug in one-third of patients. OCA was also effective in patients who had overlap between autoimmune hepatitis and primary biliary cholangitis.

Common Variable Immunodeficiency and Liver Involvement

Common variable immunodeficiency (CVID) is a primary B-cell immunodeficiency disorder, characterized by remarkable hypogammaglobulinemia. The disease can develop at any age without gender predominance. The prevalence of CVID varies widely worldwide. The underlying causes of CVID remain largely unknown; primary B-cell dysfunctions, defects in T cells and antigen-presenting cells are involved. Although some monogenetic defects have been identified in some CVID patients, it is likely that CVID is polygenic. Patients with CVID develop recurrent and chronic infections (e.g., bacterial infections of the respiratory or gastrointestinal tract), autoimmune diseases, lymphoproliferation, malignancies, and granulomatous lesions. Interestingly, autoimmunity can be the only clinical manifestation of CVID at the time of diagnosis and may even develop prior to hypogammaglobulinemia. The diagnosis of CVID is largely based on the criteria established by European Society for Immunodeficiencies and Pan-American Group for Immunodeficiency (ESID/PAGID) and with some recent modifications. The disease can affect multiple organs, including the liver. Clinical features of CVID patients with liver involvement include abnormal liver biochemistries, primarily elevation of alkaline phosphatase (ALP), nodular regenerative hyperplasia (NRH), or liver cirrhosis and its complications. Replacement therapy with immunoglobulin (Ig) and anti-infection therapy are the primary treatment regimen for CVID patients. No specific therapy for liver involvement of CVID is currently available, and liver transplantation is an option only in select cases. The prognosis of CVID varies widely. Further understanding in the etiology and pathophysiology will facilitate early diagnosis and treatments to improve prognosis.

Genetics and epigenetics of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) has been considered a multifactorial autoimmune disease presumably arising from a combination of environmental and genetic factors, with genetic inheritance mostly suggested by familial occurrence and high concordance rate among monozygotic twins. In the last decade, genome-wide association studies, new data on sex chromosome defects and instabilities, and initial evidence on the role of epigenetic abnormalities have strengthened the crucial importance of genetic and epigenetic factors in determining the susceptibility of PBC. High-throughput genetic studies in particular have revolutionized the search for genetic influences on PBC and have the potential to be translated into clinical and therapeutic applications, although more biological knowledge on candidate genes is now needed. In this review, these recent discoveries will be critically summarized with particular focus on the possible steps that may transfer genetic and epigenetic knowledge to direct health benefits in patients with PBC.

Modulation of CD4⁺ T cell responses following splenectomy in hepatitis C virus-related liver cirrhosis

Dysfunction of T cells is a common feature in chronic persistent viral infections, including hepatitis C virus (HCV), and although hepatic and peripheral T cells have been studied extensively in chronic HCV hepatitis, the role of splenic T cell responses in such patients is poorly defined. This is an important issue, as thrombocytopenia is a complication of HCV-related liver cirrhosis (LC), due to splenic platelet sequestration and bone marrow suppression; splenectomy has been proposed to treat such patients. Herein, we studied peripheral blood mononuclear cells (PBMC) and splenic lymphoid subpopulations from a total of 22 patients, including 15 with HCV-related LC with marked thrombocytopenia treated with splenectomy, and seven controls. CD4(+) T cells from peripheral blood and spleen were isolated and phenotype and function evaluated. Splenic CD4(+) T cells in patients with LC expressed molecules associated with inhibitory signalling, including increased frequency of negative markers such as cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and programmed death 1 (PD-1) and decreased production of cytokines. Patients with LC manifest higher levels of splenic CD4(+) regulatory T cells and PD-L1- and PD-L2-expressing cells than controls. Blocking of PD-1/PD-1 ligand interaction reconstituted proliferative and cytokine responses of splenic mononuclear cells (SMC) from patients with LC. Splenectomy was followed by an increase in the ratio of interferon (IFN)-γ to interleukin (IL)-10 and a reduction of PD-1-expressing CD4(+) T cells in peripheral blood. Our data suggest that peripheral tolerance is promoted by the spleen in LC via the up-regulated expression of PD-1 ligands.

Molecular and Immunological Characterization of Biliary Tract Cancers: A Paradigm Shift Towards a Personalized Medicine

Biliary tract cancers (BTCs) are a group of rare cancers that account for up to 3-5% of cancer patients worldwide. BTCs include cholangiocarcinoma (CCA), gallbladder cancer (GBC), and ampulla of Vater cancer (AVC). They are frequently diagnosed at an advanced stage when the disease is often found disseminated. A late diagnosis highly compromises surgery, the only potentially curative option. Current treatment regimens include a combination of chemotherapeutic drugs gemcitabine with cisplatin that have a limited efficiency since more than 50% of patients relapse in the first year. More recently, an inhibitor of fibroblast growth factor receptor 2 (FGFR2) was approved as a second-line treatment, based on the promising results from the NCT02924376 clinical trial. However, novel secondary treatment options are urgently needed. Recent molecular characterization of CCA and GBC highlighted the molecular heterogeneity, etiology, and epidemiology in BTC development and lead to the classification of the extrahepatic CCA into four types: metabolic, proliferating, mesenchymal, and immune type. Differences in the immune infiltration and tumor microenvironment (TME) have been described as well, showing that only a small subset of BTCs could be classified as an immune "hot" and targeted with the immunotherapeutic drugs. This recent evidence has opened a way to new clinical trials for BTCs, and new drug approvals are highly expected by the medical community.

Implications of genome-wide association studies in novel therapeutics in primary biliary cirrhosis

Genome-wide association studies (GWAS) have revolutionized the search for genetic influences on complex disorders, such as primary biliary cirrhosis (PBC). Recent GWAS have identified many disease-associated genetic variants. These, overall, highlighted the remarkable contribution of key immunological pathways in PBC that may be involved in the initial mechanisms of loss of tolerance and the subsequent inflammatory response and chronic bile duct damage. Results from GWAS have the potential to be translated in biological knowledge and, hopefully, clinical application. There are a number of immune pathways highlighted in GWAS that may have therapeutic implications in PBC and in other autoimmune diseases, such as the anti-interleukin-12/interleukin-23, nuclear factor-kb, tumor necrosis factor, phosphatidylinositol signaling and hedgehog signaling pathways. Further areas in which GWAS findings are leading to clinical applications either in PBC or in other autoimmune conditions, include disease classification, risk prediction and drug development. In this review we outline the possible next steps that may help accelerate progress from genetic studies to the biological knowledge that would guide the development of predictive, preventive, or therapeutic measures in PBC.

Tumor-Infiltrating Lymphocytes and Macrophages in Intrahepatic Cholangiocellular Carcinoma. Impact on Prognosis after Complete Surgery

BACKGROUND

Immune infiltrate impacts prognosis of several tumors. To assess the prognostic impact of tumor-infiltrating lymphocytes and macrophages in patients undergoing resection for intrahepatic cholangiocellular carcinoma (ICC).

METHODS

All consecutive patients undergoing surgery for ICC between 2008 and 2016 were considered. Inclusion criteria were complete resection and follow-up > 12 months. Tissue sections were immunostained for CD3+, CD4+, CD8+, Foxp3+, and CD68+. The number of positive cells was quantified using a computer-aided image analysis system. Different cut-off values were tested as predictors of overall survival (OS).

RESULTS

Fifty-three patients were analyzed. ICC were T1 in 28 patients, multifocal in 11, and N+ in 13. After a median follow-up of 42 months, 5-year OS was 52.1%. The following immune infiltrate values were associated with better OS: CD3+ > 0.10% (5-year OS 63.3% vs. 13.6% if ≤ 0.10%, p = 0.001); CD8+ > 0.10% (56.2% vs. 28.6% if ≤ 0.10%, p = 0.051); Foxp3+ absent (59.4% vs. 16.0% if present, p = 0.049). CD4+ and CD68+ infiltrates were not associated with OS. Three-year OS rates in patients with 0, 1, and ≥ 2 negative prognostic factors were 73.6%, 47.3%, and 14.3%, respectively (p < 0.001). CD3+ infiltrate stratified prognosis in T1 tumors (3-year OS 71.7% if CD3+ > 0.10% vs. 14.3% if ≤ 0.10%, p < 0.001).

CONCLUSIONS

Tumor-infiltrating lymphocytes are associated with prognosis of ICC patients after complete surgery. CD3+ and CD8+ infiltrate is associated with higher survival and lower recurrence risk, while Foxp3+ infiltrate is associated with worse prognosis. CD3+ infiltrate allows refining prediction of prognosis in early tumors.

X Chromosome Contribution to the Genetic Architecture of Primary Biliary Cholangitis

BACKGROUND & AIMS

Genome-wide association studies in primary biliary cholangitis (PBC) have failed to find X chromosome (chrX) variants associated with the disease. Here, we specifically explore the chrX contribution to PBC, a sexually dimorphic complex autoimmune disease.

METHODS

We performed a chrX-wide association study, including genotype data from 5 genome-wide association studies (from Italy, United Kingdom, Canada, China, and Japan; 5244 case patients and 11,875 control individuals).

RESULTS

Single-marker association analyses found approximately 100 loci displaying P < 5 × 10-4, with the most significant being a signal within the OTUD5 gene (rs3027490; P = 4.80 × 10-6; odds ratio [OR], 1.39; 95% confidence interval [CI], 1.028-1.88; Japanese cohort). Although the transethnic meta-analysis evidenced only a suggestive signal (rs2239452, mapping within the PIM2 gene; OR, 1.17; 95% CI, 1.09-1.26; P = 9.93 × 10-8), the population-specific meta-analysis showed a genome-wide significant locus in East Asian individuals pointing to the same region (rs7059064, mapping within the GRIPAP1 gene; P = 6.2 × 10-9; OR, 1.33; 95% CI, 1.21-1.46). Indeed, rs7059064 tags a unique linkage disequilibrium block including 7 genes: TIMM17B, PQBP1, PIM2, SLC35A2, OTUD5, KCND1, and GRIPAP1, as well as a superenhancer (GH0XJ048933 within OTUD5) targeting all these genes. GH0XJ048933 is also predicted to target FOXP3, the main T-regulatory cell lineage specification factor. Consistently, OTUD5 and FOXP3 RNA levels were up-regulated in PBC case patients (1.75- and 1.64-fold, respectively).

CONCLUSIONS

This work represents the first comprehensive study, to our knowledge, of the chrX contribution to the genetics of an autoimmune liver disease and shows a novel PBC-related genome-wide significant locus.

Stereotactic Radiotherapy after Incomplete Transarterial (Chemo-) Embolization (TAE\TACE) versus Exclusive TAE or TACE for Treatment of Inoperable HCC: A Phase III Trial (NCT02323360)

Background: Hepatocellular carcinoma (HCC) is the most frequent liver malignancy and a leading cause of cancer death in the world. In unresectable HCC patients, transcatheter arterial (chemo-) embolization (TAE/TACE) has shown a disease response in 15-55% of cases. Though multiple TAE/TACE courses can be administered in principle, Stereotactic Body Radiotherapy (SBRT) has emerged as an alternative option in the case of local relapse following multiple TAE/TACE courses. Methods: This is a single-center, prospective, randomized, controlled, parallel-group superiority trial of SBRT versus standard TAE/TACE for the curative treatment of the intermediate stage of HCC after an incomplete response following TAE/TACE (NCT02323360). The primary endpoint is 1-year local control (LC): 18 events were needed to assess a 45% difference (HR: 0.18) in favor of SBRT. The secondary endpoints are 1-year Progression-Free Survival (PFS), Distant Recurrence-Free Survival (DRFS), Overall Survival (OS) and the incidence of acute and late complications. Results: At the time of the final analysis, 40 patients were enrolled, 19 (49%) in the TAE/TACE arm and 21 (51%) in the SBRT arm. The trial was prematurely closed due to slow accrual. The 1- and 2-year LC rates were 57% and 36%. The use of SBRT resulted in superior LC as compared to TAE/TACE rechallenge (median not reached versus 8 months, p = 0.0002). PFS was 29% and 16% at 1 and 2 years, respectively. OS was 86% and 62% at 1 year and 2 years, respectively. In the TAE arm, PFS was 13% and 6% at 1 and 2 years, respectively. In the SBRT arm, at 1 and 2 years, PFS was 37% and 21%, respectively. OS at 1 and 2 years was 75% and 64% in the SBRT arm and 95% and 57% in the TACE arm, respectively. No grade >3 toxicity was recorded. Conclusions: SBRT is an effective treatment option in patients affected by inoperable HCC experiencing an incomplete response following ≥1 cycle of TAE/TAC.