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Serrated polyposis syndrome (SPS) is associated with a high risk for colorectal cancer. Intense promoter hypermethylation is a frequent molecular finding in the serrated pathway and may be present in normal mucosa, predisposing to the formation of serrated lesions. To identify novel biomarkers for SPS, fresh-frozen samples of normal mucosa from 50 patients with SPS and 19 healthy individuals were analyzed by using the 850K BeadChip Technology (Infinium). Aberrant methylation levels were correlated with gene expression using a next-generation transcriptome profiling tool. Two validation steps were performed on independent cohorts: first, on formalin-fixed, paraffin-embedded tissue of the normal mucosa; and second, on 24 serrated lesions. The most frequently hypermethylated genes were HLA-F, SLFN12, HLA-DMA, and RARRES3; and the most frequently hypomethylated genes were PIWIL1 and ANK3 (Δβ = 10%; P < 0.05). Expression levels of HLA-F, SLFN12, and HLA-DMA were significantly different between SPS patients and healthy individuals and correlated well with the methylation status of the corresponding differentially methylated region (fold change, >20%; r > 0.55; P < 0.001). Significant hypermethylation of CpGs in the gene body of HLA-F was also found in serrated lesions (Δβ = 23%; false discovery rate = 0.01). Epigenome-wide methylation profiling has revealed numerous differentially methylated CpGs in normal mucosa from SPS patients. Significant hypermethylation of HLA-F is a novel biomarker candidate for SPS., (Copyright © 2022 Association for Molecular Pathology and American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Background & Aims: Management of long-term immunosuppression following liver transplantation (LT) remains empirical. Surveillance liver biopsies in combination with transcriptional profiling could overcome this challenge by identifying recipients with active alloimmune-mediated liver damage despite normal liver tests, but this approach lacks applicability. Our aim was to investigate the utility of non-invasive tools for the stratification of stable long-term survivors of LT, according to their immunological risk and need for immunosuppression., Methods: We conducted a cross-sectional multicentre study of 190 adult LT recipients assessed to determine their eligibility to participate in an immunosuppression withdrawal trial. Patients had stable liver allograft function and had been transplanted for non-autoimmune non-replicative viral liver disease >3 years before inclusion. We performed histological, immunogenetic and serological studies and measured the intrahepatic transcript levels of an 11-gene classifier highly specific for T cell-mediated rejection (TCMR)., Results: In this cohort, 35.8% of patients harboured clinically silent fibro-inflammatory liver lesions (13.7% had mild damage and 22.1% had moderate-to-severe damage). The severity of liver allograft damage was positively associated with TCMR-related transcripts, class II donor-specific antibodies (DSAs), ALT, AST, and liver stiffness measurement (LSM), and negatively correlated with serum creatinine and tacrolimus trough levels. Liver biopsies were stratified according to their TCMR transcript levels using a cut-off derived from biopsies with clinically significant TCMR. Two multivariable prediction models, integrating ALT+LSM or ALT+class II DSAs, had a high discriminative capacity for classifying patients with or without alloimmune damage. The latter model performed well in an independent cohort of 156 liver biopsies obtained from paediatric liver recipients with similar inclusion/exclusion criteria., Conclusion: ALT, class II DSAs and LSM are valuable tools to non-invasively identify stable LT recipients without significant underlying alloimmunity who could benefit from minimisation of immunosuppression., Lay Summary: A large proportion of liver transplant patients with normal liver tests have inflammatory liver lesions, which in 17% of cases are molecularly indistinguishable from those seen at the time of rejection. ALT, class II donor-specific antibodies and liver stiffness are useful in identifying patients with this form of subclinical rejection. We propose these markers as a useful tool to help clinicians determine if the immunosuppression administered is adequate., Competing Interests: Conflict of interest The authors have no conflicts of interest to declare. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2021. Published by Elsevier B.V.)

Background & Aims: Porto-sinusoidal vascular disease (PSVD) is a rare vascular liver disease of unknown etiology that causes portal hypertension. It usually affects young individuals and shortens live expectancy. The deregulated pathways involved in PSVD development are unknown and therefore we lack curative treatments. The purpose of this study was to integrate transcriptomic and clinical data by comprehensive network-based modeling in order to uncover altered biological processes in patients with PSVD., Methods: We obtained liver tissue samples from 20 consecutive patients with PSVD and 21 sex- and age-matched patients with cirrhosis and 13 histologically normal livers (HNL) (initial cohort) and performed transcriptomic analysis. Microarray data were analyzed using weighted gene correlation network analysis to identify clusters of highly correlated genes differently expressed in patients with PSVD. We next evaluated the molecular pathways enriched in patients with PSVD and the core-related genes from the most significantly enriched pathways in patients with PSVD. Our main findings were validated using RNA sequencing in a different cohort of PSVD, cirrhosis and HNL (n = 8 for each group)., Results: Patients with PSVD have a distinctive genetic profile enriched mainly in canonical pathways involving hemostasis and coagulation but also lipid metabolism and oxidative phosphorylation. Serpin family (SERPINC1), the apolipoproteins (APOA, APOB, APOC), ATP synthases (ATP5G1, ATP5B), fibrinogen genes (FGB, FGA) and alpha-2-macroglobulin were identified as highly connective genes that may have an important role in PSVD pathogenesis., Conclusion: PSVD has a unique transcriptomic profile and we have identified deregulation of pathways involved in vascular homeostasis as the main pathogenic event of disease development., Lay Summary: Porto-sinusoidal vascular disease is a rare but life-shortening disease that affects mainly young people. Knowledge of the disrupted pathways involved in its development will help to identify novel therapeutic targets and new treatments. Using a systems biology approach, we identify that pathways regulating endothelial function and tone may act as drivers of porto-sinusoidal vascular disease., Competing Interests: Conflict of interest The authors involved in this study declare they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2021. Published by Elsevier B.V.)

The description of protective humoral and T cell immune responses specific against SARS-CoV-2 has been reported among immunocompetent (IC) individuals developing COVID-19 infection. However, its characterization and determinants of poorer outcomes among the at-risk solid organ transplant (SOT) patient population have not been thoroughly investigated. Cytokine-producing T cell responses, such as IFN-γ, IL-2, IFN-γ/IL-2, IL-6, IL-21, and IL-5, against main immunogenic SARS-CoV-2 antigens and IgM/IgG serological immunity were tracked in SOT (n = 28) during acute infection and at two consecutive time points over the following 40 days of convalescence and were compared to matched IC (n = 16) patients admitted with similar moderate/severe COVID-19. We describe the development of a robust serological and functional T cell immune responses against SARS-CoV-2 among SOT patients, similar to IC patients during early convalescence. However, at the infection onset, SOT displayed lower IgG seroconversion rates (77% vs. 100%; p = .044), despite no differences on IgG titers, and a trend toward decreased SARS-CoV-2-reactive T cell frequencies, especially against the membrane protein (7 [0-34] vs. 113 [15-245], p = .011, 2 [0-9] vs. 45 [5-74], p = .009, and 0 [0-2] vs. 13 [1-24], p = .020, IFN-γ, IL-2, and IFN-γ/IL-2 spots, respectively). In summary, our data suggest that despite a certain initial delay, SOT population achieve comparable functional immune responses than the general population after moderate/severe COVID-19., (© 2021 The American Society of Transplantation and the American Society of Transplant Surgeons.)