Whole-exome sequencing reveals novel cancer genes and actionable targets in biliary tract cancers in primary sclerosing cholangitis.

BACKGROUND: People with primary sclerosing cholangitis (PSC) have a 20% lifetime risk of biliary tract cancer (BTC). Using whole-exome sequencing, we characterized genomic alterations in tissue samples from BTC with underlying PSC. METHODS: We extracted DNA from formalin-fixed, paraffin-embedded tumor and paired nontumor tissue from 52 resection or biopsy specimens from patients with PSC and BTC and performed whole-exome sequencing. Following copy number analysis, variant calling, and filtering, putative PSC-BTC-associated genes were assessed by pathway analyses and annotated to targeted cancer therapies. RESULTS: We identified 53 candidate cancer genes with a total of 123 nonsynonymous alterations passing filtering thresholds in 2 or more samples. Of the identified genes, 19% had not previously been implicated in BTC, including CNGA3, KRT28, and EFCAB5. Another subset comprised genes previously implicated in hepato-pancreato-biliary cancer, such as ARID2, ELF3, and PTPRD. Finally, we identified a subset of genes implicated in a wide range of cancers such as the tumor suppressor genes TP53, CDKN2A, SMAD4, and RNF43 and the oncogenes KRAS, ERBB2, and BRAF. Focal copy number variations were found in 51.9% of the samples. Alterations in potential actionable genes, including ERBB2, MDM2, and FGFR3 were identified and alterations in the RTK/RAS (p = 0.036), TP53 (p = 0.04), and PI3K (p = 0.043) pathways were significantly associated with reduced overall survival. CONCLUSIONS: In this exome-wide characterization of PSC-associated BTC, we delineated both PSC-specific and universal cancer genes. Our findings provide opportunities for a better understanding of the development of BTC in PSC and could be used as a platform to develop personalized treatment approaches.

Early and accurate detection of cholangiocarcinoma in patients with primary sclerosing cholangitis by methylation markers in bile.

BACKGROUND AND AIMS: Primary sclerosing cholangitis (PSC) is associated with increased risk of cholangiocarcinoma (CCA). Early and accurate CCA detection represents an unmet clinical need as the majority of patients with PSC are diagnosed at an advanced stage of malignancy. In the present study, we aimed at establishing robust DNA methylation biomarkers in bile for early and accurate diagnosis of CCA in PSC. APPROACH AND RESULTS: Droplet digital PCR (ddPCR) was used to analyze 344 bile samples from 273 patients with sporadic and PSC-associated CCA, PSC, and other nonmalignant liver diseases for promoter methylation of cysteine dioxygenase type 1, cannabinoid receptor interacting protein 1, septin 9, and vimentin. Receiver operating characteristic (ROC) curve analyses revealed high AUCs for all four markers (0.77-0.87) for CCA detection among patients with PSC. Including only samples from patients with PSC diagnosed with CCA ≤ 12 months following bile collection increased the accuracy for cancer detection, with a combined sensitivity of 100% (28/28) and a specificity of 90% (20/203). The specificity increased to 93% when only including patients with PSC with longtime follow-up (> 36 months) as controls, and remained high (83%) when only including patients with PSC and dysplasia as controls (n = 23). Importantly, the bile samples from the CCA-PSC ≤ 12 patients, all positive for the biomarkers, included both early-stage and late-stage CCA, different tumor growth patterns, anatomical locations, and carbohydrate antigen 19-9 levels. CONCLUSIONS: Using highly sensitive ddPCR to analyze robust epigenetic biomarkers, CCA in PSC was accurately detected in bile, irrespective of clinical and molecular features, up to 12 months before CCA diagnosis. The findings suggest a potential for these biomarkers to complement current detection and screening methods for CCA in patients with PSC.

Circulating Macrophage Activation Markers Predict Transplant-Free Survival in Patients With Primary Sclerosing Cholangitis.

INTRODUCTION: Primary sclerosing cholangitis (PSC) is a progressive liver disease characterized by bile duct inflammation and fibrosis. The role of macrophages in PSC development and progression is less studied. Macrophage activation markers soluble (s)CD163 and mannose receptor (sMR) are associated with disease severity and outcome in other liver diseases, but not previously investigated in PSC. We evaluated sCD163 and sMR regarding disease severity and prognosis in patients with PSC. METHODS: We investigated 2 independent PSC cohorts from Oslo (n = 138) and Helsinki (n = 159) and analyzed blood sCD163 and sMR levels. The Mayo score, Enhanced Liver Fibrosis Test, and Amsterdam-Oxford model were assessed for comparison. RESULTS: Median (interquartile range) sCD163 was 3.32 (2.27-5.60) and 1.96 (1.47-2.70) mg/L in the Oslo and Helsinki cohorts, respectively, reflecting differences in disease severity between cohorts. Median sMR was similar in both cohorts, 0.28 (0.22-0.44) and 0.28 mg/L (0.20-0.36), respectively. In both cohorts, sCD163 and sMR levels raised with increasing disease severity (liver enzymes, Mayo score, and enhanced liver fibrosis test). Patients with high baseline levels of sCD163 had shorter transplant-free survival than patients with low baseline levels. Furthermore, sCD163 was associated with transplant-free survival in univariate cox-regression analyses. Both sCD163 and sMR performed better in the Oslo cohort of more severely diseased patients than those in the Helsinki cohort of more mildly diseased patients. DISCUSSION: Macrophage activation markers are elevated according to disease severity suggesting an important role of macrophages in PSC. Furthermore, sCD163 was identified as a prognostic marker and predictor of transplant-free survival in PSC (see Visual Abstract, Supplementary Digital Content 4, http://links.lww.com/CTG/A516).

Genomic Characterization of Cholangiocarcinoma in Primary Sclerosing Cholangitis Reveals Therapeutic Opportunities.

BACKGROUND AND AIMS: Lifetime risk of biliary tract cancer (BTC) in primary sclerosing cholangitis (PSC) may exceed 20%, and BTC is currently the leading cause of death in patients with PSC. To open new avenues for management, we aimed to delineate clinically relevant genomic and pathological features of a large panel of PSC-associated BTC (PSC-BTC). APPROACH AND RESULTS: We analyzed formalin-fixed, paraffin-embedded tumor tissue from 186 patients with PSC-BTC from 11 centers in eight countries with all anatomical locations included. We performed tumor DNA sequencing at 42 clinically relevant genetic loci to detect mutations, translocations, and copy number variations, along with histomorphological and immunohistochemical characterization. Regardless of the anatomical localization, PSC-BTC exhibited a uniform molecular and histological characteristic similar to extrahepatic cholangiocarcinoma. We detected a high frequency of genomic alterations typical of extrahepatic cholangiocarcinoma, such as TP53 (35.5%), KRAS (28.0%), CDKN2A (14.5%), and SMAD4 (11.3%), as well as potentially druggable mutations (e.g., HER2/ERBB2). We found a high frequency of nontypical/nonductal histomorphological subtypes (55.2%) and of the usually rare BTC precursor lesion, intraductal papillary neoplasia (18.3%). CONCLUSIONS: Genomic alterations in PSC-BTC include a significant number of putative actionable therapeutic targets. Notably, PSC-BTC shows a distinct extrahepatic morpho-molecular phenotype, independent of the anatomical location of the tumor. These findings advance our understanding of PSC-associated cholangiocarcinogenesis and provide strong incentives for clinical trials to test genome-based personalized treatment strategies in PSC-BTC.

Autotaxin activity predicts transplant-free survival in primary sclerosing cholangitis.

Autotaxin has been associated with liver disease severity and transplant-free survival. This study aimed to validate autotaxin as a biomarker in two cohorts of Norwegian large-duct PSC patients, one discovery panel (n = 165) and one validation panel (n = 87). Serum activity of autotaxin was measured in diluted sera by a fluorometric enzymatic assay. Patients reaching an end-point, liver transplantation or death, (discovery panel: n = 118 [71.5%]; validation panel: n = 35 [40.2%]), showed higher autotaxin activity compared with the other patients, P < 0.001 and P = 0.004, respectively. Kaplan-Meier survival analyses showed a strong association between increasing autotaxin activity and shorter liver transplant-free survival (discovery panel: P < 0.001, validation panel: P = 0.001). There was no relationship between autotaxin activity and the presence of inflammatory bowel disease or occurrence of hepatobiliary malignancy. In a multivariable analysis, high autotaxin activity was associated with an increased risk of liver transplantation or death (hazard ratio 2.03 (95% confidence interval 1.21-3.40), P < 0.01), independent from Mayo risk score, an in-house enhanced liver fibrosis score and interleukin-8 in serum. In conclusion, increased serum autotaxin activity is associated with reduced liver transplant-free survival independent from Mayo risk score and markers of inflammation and fibrosis.

Cholangiocarcinoma is associated with a raised enhanced liver fibrosis score independent of primary sclerosing cholangitis.

BACKGROUND: Cholangiocarcinoma (CCA) complicates primary sclerosing cholangitis (PSC) in 10%-20% of cases, but current tools for prediction of a CCA diagnosis are inadequate. Recently, we demonstrated the utility of the enhanced liver fibrosis (ELF) test to stratify prognosis in PSC. We observed that patients with PSC + CCA had significantly higher ELF score than those with PSC alone. In this study, we aimed to investigate further this association in a larger cohort of PSC patients with CCA compared with patients with PSC or CCA alone. MATERIALS AND METHODS: Stored sera from patients with PSC (n = 119), CCA without known chronic liver disease (n = 36) and PSC + CCA (n = 32) were tested for ELF. ELF score, gender, age, age at disease diagnosis, inflammatory bowel disease, PSC duration and severity, and CCA features were compared amongst the three cohorts. Factors related to an elevated ELF score were investigated. RESULTS: Enhanced liver fibrosis score was significantly higher in patients with CCA without underlying chronic liver disease and in patients with PSC + CCA compared to those with PSC alone (P < 0.001). In multivariate analysis, elevated ELF score was associated with the diagnosis of CCA independently of age and PSC status (P < 0.001). CONCLUSIONS: Enhanced liver fibrosis score was elevated in patients with CCA irrespective of the presence of PSC, and independently of liver disease stage. Our results indicate that the association between high ELF score and CCA may be related to the tumour's desmoplastic nature, independent of background liver fibrosis, suggesting that ELF score could be used to risk stratify for CCA in PSC.

Risk factors and prognosis for recurrent primary sclerosing cholangitis after liver transplantation: a Nordic Multicentre Study.

OBJECTIVES: The risk for recurrent primary sclerosing cholangitis (rPSC) after liver transplantation is associated with inflammatory bowel disease (IBD). We assessed the frequency of rPSC and studied risk factors for recurrent disease with special focus on IBD. We also evaluated the importance of rPSC for prognosis. MATERIALS AND METHODS: All liver transplanted PSC patients in the Nordic countries between 1984 and 2007 (n = 440), identified by the Nordic Liver Transplant Registry, were studied. Data were retrieved from patients' chart reviews. Multivariable Cox regression models were used to calculate risk factors for rPSC and death. RESULTS: Of the 440 patients with a follow-up time after liver transplantation of 3743 patient years, rPSC was diagnosed in 19% (n = 85). Colectomy before liver transplantation was associated with a reduced risk of rPSC (HR 0.49; 95% CI, 0.26-0.94, p = 0.033). Neither high IBD activity nor presence of IBD flares before or after liver transplantation was associated with rPSC. Treatment with tacrolimus was an independent risk factor associated with increased risk for rPSC (HR, 1.81; 95% CI, 1.15-2.86, p = 0.010). The risk of dying or needing a re-transplantation after rPSC was increased in all age groups, but highest in patients transplanted before 40 years of age (HR 7.3; 95% CI, 4.1-12.8, p = 0.0001). CONCLUSIONS: This study confirms that colectomy before liver transplantation is associated with a decreased risk of rPSC. Inflammatory activity of IBD was not associated with the risk of rPSC. Tacrolimus was an independent risk factor for PSC recurrence and its use as first line immunosuppression in PSC needs further study.

Enhanced liver fibrosis test predicts transplant-free survival in primary sclerosing cholangitis, a multi-centre study.

BACKGROUND & AIMS: Biomarkers reflecting disease activity and prognosis in primary sclerosing cholangitis (PSC) have not been firmly established. Enhanced liver fibrosis (ELF) test was previously reported to predict outcome in PSC. We aimed to validate the prognostic utility of ELF test in an independent, multi-centre, retrospective PSC study population. METHODS: We collected serum samples from PSC patients from seven countries. We estimated rates of transplant-free survival by the Kaplan-Meier method, used Cox proportional hazards regression to explore the association between ELF test and clinical outcome and determined prognostic performance of ELF test by computing the area under the receiver operating characteristic (AUC-ROC) curve. RESULTS: The final analysis included 534 PSC patients (61% males). Features of autoimmune hepatitis or concomitant inflammatory bowel disease affected 44 (8%) and 379 (71%) patients respectively. ELF test levels were higher in patients reaching the combined endpoint liver transplantation or death (median 10.9 [Interquartile range (IQR): 9.8-12.1]; n=24 deaths, 79 liver transplantations) compared to those censored (8.8 [IQR: 8.0-9.8]); P<.001. ELF test expressed as mild, moderate and severe fibrosis was significantly associated with the risk of reaching the endpoint (P<.001). ELF test independently predicted clinical outcome (Hazard ratio 1.31; 95% confidence interval [1.05-1.65]; P=.018), and enabled good discrimination between PSC patients with and without endpoint (AUC-ROC: 0.79). CONCLUSION: Our retrospective data validates the predictive utility of ELF test for clinical outcomes in PSC. The clinical utility of biomarkers for fibrosis in patients with PSC should be assessed in prospective patient cohorts.

Antineutrophil antibodies define clinical and genetic subgroups in primary sclerosing cholangitis.

BACKGROUND & AIMS: The strongest genetic risk factors in primary sclerosing cholangitis (PSC) are encoded in the HLA complex. Antineutrophil cytoplasmic antibodies (ANCA) have been reported in up to 94% of PSC patients, but their clinical significance and immunogenetic basis are ill defined. We aimed to characterize clinical and genetic associations of ANCA in PSC. METHODS: Antineutrophil cytoplasmic antibodies were analysed with indirect immunofluorescence in 241 Norwegian PSC patients. HLA-B and HLA-DRB1 genotyping was performed in the patients and in 368 healthy controls. Data on perinuclear ANCA (pANCA) and HLA-DRB1 were available from 274 ulcerative colitis (UC) patients without known liver disease. RESULTS: Antineutrophil cytoplasmic antibodies were found in 193 (80%) of the PSC patients, with pANCA in 169 (70%). ANCA-positive patients were younger than ANCA negative at diagnosis of PSC and had a lower frequency of biliary cancer (9% vs 19%, P=.047). There were no differences between PSC patients with and without inflammatory bowel disease. Genetically, the strong PSC risk factors HLA-B*08 (frequency in healthy 13%) and DRB1*03 (14%) were more prevalent in ANCA-positive than -negative patients (43% vs 25%, P=.0012 and 43% vs 25%, P=.0015 respectively). The results were similar when restricting the analysis to pANCA-positive patients. In UC patients without liver disease, HLA-DRB1*03 was more prevalent in pANCA-positive compared with -negative patients (P=.03). CONCLUSIONS: Antineutrophil cytoplasmic antibodies identified PSC patients with particular clinical and genetic characteristics, suggesting that ANCA may mark a clinically relevant pathogenetic subgroup in the PSC-UC disease spectrum.

Genome-wide association study of primary sclerosing cholangitis identifies new risk loci and quantifies the genetic relationship with inflammatory bowel disease.

Primary sclerosing cholangitis (PSC) is a rare progressive disorder leading to bile duct destruction; ∼75% of patients have comorbid inflammatory bowel disease (IBD). We undertook the largest genome-wide association study of PSC (4,796 cases and 19,955 population controls) and identified four new genome-wide significant loci. The most associated SNP at one locus affects splicing and expression of UBASH3A, with the protective allele (C) predicted to cause nonstop-mediated mRNA decay and lower expression of UBASH3A. Further analyses based on common variants suggested that the genome-wide genetic correlation (rG) between PSC and ulcerative colitis (UC) (rG = 0.29) was significantly greater than that between PSC and Crohn's disease (CD) (rG = 0.04) (P = 2.55 × 10-15). UC and CD were genetically more similar to each other (rG = 0.56) than either was to PSC (P < 1.0 × 10-15). Our study represents a substantial advance in understanding of the genetics of PSC.

No Evidence That Azathioprine Increases Risk of Cholangiocarcinoma in Patients With Primary Sclerosing Cholangitis.

BACKGROUND & AIMS: Patients with primary sclerosing cholangitis (PSC) are at increased risk for developing cholangiocarcinoma (CCA). Patients with PSC also can have inflammatory bowel diseases (IBDs) or features of autoimmune hepatitis (AIH), and therefore are treated with azathioprine. Azathioprine has been associated with an increased risk for malignancy, therefore we investigated whether azathioprine use affects the risk of CCA in persons with PSC. METHODS: We performed a retrospective study of well-defined patients with PSC using data collected from 3 large-volume, tertiary care centers in Germany and Norway. We analyzed data from 638 patients (70% men; 5900 patient-years of follow-up evaluation); 91 patients had received azathioprine therapy (considered to be effective at 90 days after first intake). Risk analysis was performed using the Cox proportional hazard model when risks competing with study end points were present. RESULTS: Of patients who received azathioprine treatment, 3.3% developed CCA, compared with 6.8% of patients without azathioprine treatment. However, azathioprine did not significantly affect the risk for CCA (hazard ratio, 0.96; 95% confidence interval, 0.29-3.13; P = .94). The only factor associated with an increased risk of CCA was age 35 years or older at PSC diagnosis (hazard ratio, 3.87; 95% confidence interval, 1.96-7.67; P < .01). Patient sex, concomitant IBD, or AIH did not affect the risk of CCA. Overall, the cumulative 10-year incidence of CCA was 4.6% and the cumulative 15-year incidence was 7.7%. CONCLUSIONS: A retrospective analysis of patients with PSC treated at tertiary centers in Europe found no evidence that azathioprine significantly affects the risk of CCA. Azathioprine therefore should not be withheld from patients with PSC and concomitant IBD and/or AIH.

Expert consensus document: Cholangiocarcinoma: current knowledge and future perspectives consensus statement from the European Network for the Study of Cholangiocarcinoma (ENS-CCA).

Cholangiocarcinoma (CCA) is a heterogeneous group of malignancies with features of biliary tract differentiation. CCA is the second most common primary liver tumour and the incidence is increasing worldwide. CCA has high mortality owing to its aggressiveness, late diagnosis and refractory nature. In May 2015, the "European Network for the Study of Cholangiocarcinoma" (ENS-CCA: www.enscca.org or www.cholangiocarcinoma.eu) was created to promote and boost international research collaboration on the study of CCA at basic, translational and clinical level. In this Consensus Statement, we aim to provide valuable information on classifications, pathological features, risk factors, cells of origin, genetic and epigenetic modifications and current therapies available for this cancer. Moreover, future directions on basic and clinical investigations and plans for the ENS-CCA are highlighted.

Liver transplantation with deceased ABO-incompatible donors is life-saving but associated with increased risk of rejection and post-transplant complications.

ABO-incompatible (ABOi) liver transplantation (LT) with deceased donor organs is performed occasionally when no ABO-compatible (ABOc) graft is available. From 1996 to 2011, 61 ABOi LTs were performed in Oslo and Gothenburg. Median patient age was 51 years (range 13-75); 33 patients were transplanted on urgent indications, 13 had malignancy-related indications, and eight received ABOi grafts for urgent retransplantations. Median donor age was 55 years (range 10-86). Forty-four patients received standard triple immunosuppression with steroids, tacrolimus, and mycophenolate mofetil, and forty-four patients received induction with IL-2 antagonist or anti-CD20 antibody. Median follow-up time was 29 months (range 0-200). The 1-, 3-, 5-, and 10-year Kaplan-Meier estimates of patient survival (PS) and graft survival (GS) were 85/71%, 79/57%, 75/55%, and 59/51%, respectively, compared to 90/87%, 84/79%, 79/73%, and 65/60% for all other LT recipients in the same period. The 1-, 3-, 5-, and 10-year GS for A2 grafts were 81%, 67%, 62%, and 57%, respectively. In conclusion, ABOi LT performed with non-A2 grafts is associated with inferior graft survival and increased risk of rejection, vascular and biliary complications. ABOi LT with A2 grafts is associated with acceptable graft survival and can be used safely in urgent cases.

Indications and Outcomes in Liver Transplantation in Patients With Primary Sclerosing Cholangitis in Norway.

BACKGROUND: Primary sclerosing cholangitis (PSC) is 1 of the leading causes of liver transplantation (LTX) in Scandinavia, and an increasing number of PSC patients have been transplanted in Norway during the last 2 decades. This trend is partly attributable to the recently established practice in Norway of offering LTX to PSC patients with cholangiocellular dysplasia. Based on the controversy associated with this practice, we herein aimed to report the main features and outcomes of our LTX program in PSC. METHODS: The primary indication for LTX (quality of life/end-stage liver disease or suspected neoplasia) was retrospectively determined for 222 patients undergoing LTX for PSC or other autoimmune liver diseases (primary biliary cirrhosis/autoimmune hepatitis) with at least 5 years of follow-up. RESULTS: In PSC patients impaired quality of life (43.5%) and end-stage liver disease (38.4%) were the most frequent indications for LTX, whereas suspected neoplasia accounted for 18.1%. The proportion of PSC patients with manifest encephalopathy, variceal bleeding, or ascites declined over time. In patients with suspected neoplasia as the primary indication for LTX (n = 25), neoplasia was confirmed in the explanted liver in 20 patients (80%). Five-year survival rates for PSC patients transplanted between 2001 and 2009 were 91.9% for patients receiving LTX due to impaired quality of life or end-stage liver disease and 83.3% for suspected neoplasia. CONCLUSIONS: The PSC patients are increasingly listed for LTX at an earlier stage of their liver disease. In patients with suspected neoplasia before LTX, 5-year survival was acceptable, despite confirmation of neoplasia in 80% of the liver explants.

HLA variants related to primary sclerosing cholangitis influence rejection after liver transplantation.

AIM: To investigate influence of human leukocyte antigen (HLA) and killer immunoglobuline-like receptor (KIR) genotypes on risks of acute rejection (AR) after liver transplantation (LTX). METHODS: In this retrospective study we included 143 adult donor-recipient pairs with a minimum of 6 mo follow-up after LTX for whom DNA was available from both donor and recipients. Clinical data, all early complications including episodes and severity of AR and graft/patient survival were registered. The diagnosis of AR was based on clinical, biochemical and histological criteria. All suspected episodes of AR were biopsy confirmed. Key classical HLA loci (HLA-A, HLA-B, HLA-C and HLA-DRB1) were genotyped using Sanger sequencing. 16 KIR genes were genotyped using a novel real time PCR approach which allows for determination of the diploid copy number of each KIR gene. Immunohistochemical staining for T (CD3), B (CD20) and natural killer (NK) cells (CD56 and CD57) were performed on liver biopsies from 3 different patient groups [primary sclerosing cholangitis (PSC), primary biliary cirrhosis and non-autoimmune liver disease], 10 in each group, with similar grade of AR. RESULTS: Fourty-four (31%) patients were transplanted on the basis of PSC, 40% of them had AR vs 24% in the non-PSC group (P = 0.04). No significant impact of donor-recipient matching for HLA and KIR genotypes was detected. In the overall recipient population an increased risk of AR was detected for HLA-B*08 (P = 0.002, OR = 2.5; 95%CI: 1.4-4.6), HLA-C*07 (P = 0.001, OR = 2.4; 95%CI: 1.4-4.0) and HLA-DRB1*03 (P = 0.03, OR = 1.9; 95%CI: 1.0-3.3) and a decreased risk for HLA-DRB1*04 (P = 0.001, OR = 0.2; 95%CI: 0.1-0.5). For HLA-B*08, HLA-C*07 and DRB1*04 the associations remained evident in a subgroup analysis of non-PSC recipients (P = 0.04, P = 0.003 and P = 0.02, respectively). In PSC recipients corresponding P values were 0.002, 0.17 and 0.01 for HLA-B*08, HLA-C*07 and DRB1*04, respectively. A dosage effect of AR prevalence according to the PSC associated HLA alleles was also notable in the total recipient population. For HLA-B*08 the frequency of AR was 56% in HLA-B*08 homozygous recipients, 39% in heterozygous recipients and 21% in recipients lacking HLA-B*08 (P = 0.02). The same was observed for the HLA-C*07 allele with AR in 57%, 27% and 18% in recipients being homozygous, heterozygous and lacking HLA-C*07 respectively (P = 0.003). Immunohistochemical analysis showed similar infiltration of T, B and NK cells in biopsies with AR in all three groups. CONCLUSION: We found significant associations between the PSC-associated HLA-B*08, HLA-C*07, HLA-DRB1*03 and HLA-DRB1*04 alleles and risk of AR in liver transplant recipients.

Small duct primary sclerosing cholangitis without inflammatory bowel disease is genetically different from large duct disease.

BACKGROUND & AIMS: Small duct primary sclerosing cholangitis (PSC) is phenotypically a mild version of large duct PSC, but it is unknown whether these phenotypes share aetiology. We aimed to characterize their relationship by investigating genetic associations in the human leucocyte antigen (HLA) complex, which represent the strongest genetic risk factors in large duct PSC. METHODS: Four classical HLA loci (HLA-A, HLA-B, HLA-C and HLA-DRB1) were genotyped in 87 small duct PSC patients, 485 large duct PSC patients and 1117 controls across three geographical regions. RESULTS: HLA-DRB1*13:01 (OR = 2.0, 95% CI 1.2-3.4, P = 0.01) and HLA-B*08 (OR = 1.6, 95% CI 1.1-2.4, P = 0.02) were significantly associated with small duct PSC compared with healthy controls. Based on the observed frequency of HLA-B*08 in small duct PSC, the strongest risk factor in large duct PSC, an estimated 32% (95% CI 4-65%) of this population can be hypothesized to represent early stages or mild variants of large duct PSC. This subgroup may be constituted by small duct PSC patients with inflammatory bowel disease (IBD), which greatly resembled large duct PSC in its HLA association. In contrast, small duct PSC without IBD was only associated with HLA-DRB1*13:01(P = 0.03) and was otherwise distinctly dissimilar from large duct PSC. CONCLUSIONS: Small duct PSC with IBD resembles large duct PSC in its HLA association and may represent early stages or mild variants of large duct disease. Different HLA associations in small duct PSC without IBD could indicate that this subgroup is a different entity. HLA-DRB1*13:01 may represent a specific risk factor for inflammatory bile duct disease.

Genome-wide association analysis in primary sclerosing cholangitis and ulcerative colitis identifies risk loci at GPR35 and TCF4.

UNLABELLED: Approximately 60%-80% of patients with primary sclerosing cholangitis (PSC) have concurrent ulcerative colitis (UC). Previous genome-wide association studies (GWAS) in PSC have detected a number of susceptibility loci that also show associations in UC and other immune-mediated diseases. We aimed to systematically compare genetic associations in PSC with genotype data in UC patients with the aim of detecting new susceptibility loci for PSC. We performed combined analyses of GWAS for PSC and UC comprising 392 PSC cases, 987 UC cases, and 2,977 controls and followed up top association signals in an additional 1,012 PSC cases, 4,444 UC cases, and 11,659 controls. We discovered novel genome-wide significant associations with PSC at 2q37 [rs3749171 at G-protein-coupled receptor 35 (GPR35); P = 3.0 × 10(-9) in the overall study population, combined odds ratio [OR] and 95% confidence interval [CI] of 1.39 (1.24-1.55)] and at 18q21 [rs1452787 at transcription factor 4 (TCF4); P = 2.61 × 10(-8) , OR (95% CI) = 0.75 (0.68-0.83)]. In addition, several suggestive PSC associations were detected. The GPR35 rs3749171 is a missense single nucleotide polymorphism resulting in a shift from threonine to methionine. Structural modeling showed that rs3749171 is located in the third transmembrane helix of GPR35 and could possibly alter efficiency of signaling through the GPR35 receptor. CONCLUSION: By refining the analysis of a PSC GWAS by parallel assessments in a UC GWAS, we were able to detect two novel risk loci at genome-wide significance levels. GPR35 shows associations in both UC and PSC, whereas TCF4 represents a PSC risk locus not associated with UC. Both loci may represent previously unexplored aspects of PSC pathogenesis.

Inflammatory markers sampled by microdialysis catheters distinguish rejection from ischemia in liver grafts.

Rejection and ischemia are serious complications after liver transplantation. Early detection is mandatory, but specific markers are largely missing, particularly for rejection. The objective of this study was to explore the ability of microdialysis catheters inserted in liver grafts to detect and discriminate rejection and ischemia through postoperative measurements of inflammatory mediators. Microdialysis catheters with a 100-kDa pore size were inserted into 73 transplants after reperfusion. After the study's completion, complement activation product 5a (C5a), C-X-C motif chemokine 8 (CXCL8), CXCL10, interleukin-1 (IL-1) receptor antagonist, IL-6, IL-10, and macrophage inflammatory protein 1ß were analyzed en bloc in all grafts with biopsy-confirmed rejection (n = 12), in grafts with vascular occlusion/ischemia (n = 4), and in reference grafts with a normal postoperative course of circulating transaminase and bilirubin levels (n = 17). The inflammatory mediators were elevated immediately after graft reperfusion and decreased toward low, stable values during the first 24 hours in nonischemic grafts. In grafts suffering from rejection, CXCL10 increased significantly (P = 0.008 versus the reference group and P = 0.002 versus the ischemia group) 2 to 5 days before increases in circulating alanine aminotransferase and bilirubin levels. The area under the receiver operating characteristic curve was 0.81. Grafts with ischemia displayed increased levels of C5a (P = 0.002 versus the reference group and P = 0.008 versus the rejection group). The area under the curve was 0.99. IL-6 and CXCL8 increased with both ischemia and rejection. In conclusion, CXCL10 and C5a were found to be selective markers for rejection and ischemia, respectively.