Late liver allograft rejection is under-recognized because it is often clinically silent, liver tests are insensitive, protocol biopsies are uncommon, and the histology differs from classic early acute T cell-mediated rejection (TCMR) manifesting in the initial weeks after transplantation. Differences in tempo and pathogenesis lead to distinct clinical and histologic manifestations. Late- compared with acute-TCMR is characterized by more prevalent interface and perivenular inflammatory activity, a lymphocyte-predominant infiltrate and fibrosis, with less conspicuous portal duct-centered and subendothelial venular inflammation. The traditional Banff RAI scheme that works consistently well to diagnose acute-TCMR is less well calibrated to account for these later shifts of inflammatory target and density, risking under-diagnosis of clinically significant late-TCMR. This document lays out the histopathologic characteristics of acute- vs. late-TCMR and the rationale for updating the Banff scoring system for liver allograft rejection to better incorporate currently unrepresented histology features correlating with a molecular rejection signature into the Banff rejection scheme.

OBJECTIVES:This study aimed to investigate whether secondary iron overload in the liver mimics cirrhosis on abdominal CT scans, particularly in patients with end-stage renal disease (ESRD), and to develop a diagnostic algorithm to differentiate these conditions. METHODS:We conducted a radio-pathologic correlation study involving 4 patient groups: (1) patients with nodular regenerative hyperplasia (NRH) and no hepatic iron deposition, (2) ESRD patients with CT scans suggesting cirrhosis, (3) patients with biopsy-proven cirrhosis and hepatic iron overload, and (4) patients with biopsy-proven cirrhosis without hepatic iron overload. Two board-certified radiologists reviewed all cases in a blinded manner, and liver-related laboratory tests, along with features of portal hypertension, were assessed. RESULTS:CT scans of ESRD patients with secondary hepatic iron overload showed irregular liver contours resembling cirrhosis. However, these patients lacked thrombocytopenia, oesophageal varices, and other clinical markers of portal hypertension, which were consistently present in true cirrhosis cases. These findings suggest that imaging alone cannot reliably diagnose cirrhosis in ESRD patients. CONCLUSIONS:Secondary hepatic iron deposition in ESRD patients can create CT features that mimic cirrhosis. A comprehensive evaluation of clinical, laboratory, and imaging data is crucial for accurate diagnosis and to prevent unnecessary liver biopsies. ADVANCES IN KNOWLEDGE:This study emphasizes the importance of a multidisciplinary diagnostic approach for ESRD patients with suspected cirrhosis. The proposed algorithm helps differentiate true cirrhosis from secondary iron overload, reducing unnecessary invasive procedures, optimizing pre-transplant evaluations, and enhancing patient care.

Introduction: Simultaneous liver–kidney (SLK) transplant recipients are considered at lower immunologic risk than kidney-alone recipients, so steroid-only induction is often used. However, some centers continue to include basiliximab induction in their protocols. This study compared graft and infectious outcomes in SLK recipients receiving basiliximab (Bas) induction versus those without basiliximab (No Bas). Methods: Using TriNetX, we conducted a retrospective, propensity-score-matched study of SLK recipients comparing 3-, 6-, and 12-month graft and infectious outcomes. Patients receiving alemtuzumab or anti-thymocyte globulin were excluded; steroid induction was permitted but not required in either cohort. Maintenance immunosuppression included tacrolimus, mycophenolate, and prednisone. Cohorts were matched on 71 variables, including demographics, disease etiology, severity markers, and cPRA. Results: After matching, 292 patients were included per cohort (mean age 56.9 ± 10.1 years; 61% male). Kidney and liver rejection rates were similar. The No Bas cohort had more liver biopsies (25.5% vs. 18.2% at 1 year, p = 0.04). Kidney biopsy, graft failure, re-transplantation, delayed graft function, and mortality were comparable. Liver primary non-function was more frequent in Bas (2.8% vs. 0.4%, p = 0.04). The No Bas cohort had higher CMV at 3 months (13.4% vs. 6.7%, p = 0.008) and higher EBV at all time points (4.0% vs. 0.4% at 1 year, p = 0.004). Conclusions: SLK recipients without basiliximab induction had comparable rejection outcomes but more viral infections, potentially from greater steroid exposure, and more liver biopsies, which may reflect higher clinical suspicion for rejection or incomplete capture of rejection events in EMR data.

Background & aimsDirect-acting antivirals (DAAs) revolutionized hepatitis C (HCV) treatment. Yet, some patients present with persistent inflammation and still face adverse outcomes, including cirrhosis and hepatocellular carcinoma, despite achieving sustained virologic response (SVR).Approach & resultsThis study examined liver biopsies from 22 patients before and after DAA treatment to assess gene and protein expression changes linked to disease progression. Pre-treatment, patients exhibited two distinct profiles: one characterized by high pro-inflammatory and antiviral gene expression (pre-hot), and another with weaker expression (pre-cold). Patients with pre-hot profiles were initially associated with poor outcomes (OR = 14.0, 95% CI: 1.31–178.5; p = 0.049), but this lost significance after adjusting for baseline disease severity (adjusted OR = 8.04, 95% CI: 0.18–2123.07; p = 0.328). Baseline modified hepatitis activity index (MHAI) scores (OR = 1.90, 95% CI: 0.72–6.34) and fibrosis stage (OR = 1.65, 95% CI: 0.44–9.97) trended toward predicting poor outcomes but were not significant. Post-treatment, liver enzymes decreased, inflammatory scores improved, and type I interferon pathways were restored, yet 14 of 17 patients (82.3%, 95% CI: 64.2–100%) retained persistent lymphocytic infiltrates. In parallel, spectral imaging further revealed post-treatment shifts in macrophage populations, with a significant decrease in inflammatory subsets (CD14+, CD14+/Mac387+, p<0.05) and an increase in anti-inflammatory subsets (CD16+, CD16+/CD163+, CD16+/CD68+, p<0.05). Analysis of T cell–related marker expression before and after treatment shows that mixed lymphocytic infiltration (CD3+, CD4+, CD8+, CD45RO+) persists within the liver despite viral clearance, with high inter-patient variability likely limiting statistical significance.ConclusionsEven after achieving SVR and normalization of gene expression, the liver retained a heterogeneous T cell infiltrate, suggesting that persistent immune activity could continue to influence the risk of adverse outcomes.

Regardless of the source of injury or metabolic dysfunction, fibrosis is a frequent driver of liver pathology. Excessive liver fibrosis is caused by persistent activation of hepatic stellate cells (HSCs), which is defined by myofibroblast activation (MFA) and the epithelial-mesenchymal transition (EMT). Strategies to prevent or reverse this HSC phenotype will be critical for successful treatment of liver fibrosis. We have previously shown that full-term, cell-free human amniotic fluid (cfAF) inhibits MFA and EMT in fibroblasts in vitro. We hypothesize that cfAF treatment can attenuate HSC activation and limit liver fibrosis. We tested if cfAF could prevent liver fibrosis or HSC activation in murine models of liver damage, 3-dimensional hepatic spheroids, and HSC cultures. Administering cfAF prevented weight loss and the extent of fibrosis in mice with chronic liver damage without stimulating deleterious immune responses. Gene expression profiling and immunostaining indicated that cfAF administration in carbon tetrachloride-treated mice reduced EMT- and MFA-related biomarker abundance and modulated transcript levels associated with liver metabolism, immune regulatory pathways, and cell signaling. cfAF treatment lowered MFA biomarker levels in a dose-dependent manner in ex vivo hepatic spheroids. Treating HSCs with cfAF in vitro strongly repressed EMT. Multiomics analyses revealed that it also attenuates TGFβ-induced MFA and inflammation-associated processes. Thus, cfAF treatment prevents liver fibrosis by safeguarding against persistent HSC activation. These findings suggest that cfAF may be a safe and effective therapy for reducing liver fibrosis and preventing the development of cirrhosis and/or hepatocellular carcinoma.

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are immune-mediated liver diseases (IMLDs) that are diagnosed by a combination of clinical, serologic, and histologic features. Diagnosis may be challenging, particularly when patients have mixed features of both AIH and PBC, a disease often called overlap syndrome (OS). In addition, many patients have refractory disease. We hypothesized that adding molecular testing to the current diagnostic criteria would provide an additional tool that could assist in correctly classifying patients. RNA was isolated from liver biopsies from patients with AIH (n = 16), PBC (n =13), OS (n = 8), drug-induced/serology-negative AIH (AIH DI/Ser-neg, n = 6), or controls (n = 10). Gene expression was determined using an nCounter Sprint Profiler, and principal component analysis delineated distinct clusters for patients with an inflammatory profile due to AIH, PBC, and AIH DI/Ser-neg. Two patients with minimal histologic features of PBC clustered with the control group, and 2 patients with predominantly AIH and minimal PBC features clustered with the PBC group. A patient with OS who received treatment for both conditions showed no disease progression, whereas a patient with OS treated solely for AIH failed to respond. Conversely, one of the gene signatures from a patient diagnosed with PBC fell within the AIH group. This patient did not respond to treatment with ursodiol and ultimately required liver replacement. These findings suggest that the IMLD initially diagnosed in these patients may have been incorrectly classified. As expected, molecular analysis could not identify a distinct cluster for patients diagnosed with OS, and these had variable gene signatures that fell throughout the identified AIH or PBC groups. Cluster analysis was also able to distinguish patients with disease progression from nonprogressors with mild disease who responded to treatment. In summary, gene expression analysis may assist in confirming the type of IMLD, especially when the diagnosis is unclear. Combining molecular testing with existing criteria could provide an additional diagnostic tool, improving patient care and response to treatment. (c) 2025 THE AUTHORS. Published by Elsevier Inc. on behalf of the United States & Canadian Academy of Pathology. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).

Supplementary Data from Treatment Strategies and Mechanisms Associated with the Prevention of NASH-Associated HCC by a Toll-like Receptor 4 Inhibitor

Pyogenic liver abscess (PLA) is a potentially life-threatening disease. Early diagnosis and appropriate treatment are crucial to ensure high-quality healthcare for patients with PLA. However, this is complicated by their non-specific clinical symptoms. In addition, the etiologic organisms responsible for PLA are frequently culture-negative, thus complicating clinical decision-making. Here, we report a case of PLA caused by Streptococcus intermedius, as identified via DNA metagenomic sequencing of plasma.

Biliary adenofibroma (BAF) is a rare hepatic tumor with a high risk for malignant transformation. Since BAF shares many characteristics with other hepatic lesions, diagnosis usually requires meticulous evaluation. The literature review revealed 29 reported patients of BAF, with malignant transformation occurring in 45% of patients. High Ki-67 (>40%) and mutated/overexpressed p53 staining were associated with malignancy, but some patients also had malignant features with low Ki-67 (≤10%) and wild-type p53. We report an elderly female patient who was initially diagnosed with benign liver hemangioma based on an abdominal ultrasound. The mass enlarged by 4 cm raising concerns about potential complications, including hemorrhage, which led to hepatic segmental resection. Histopathological examination revealed predominantly BAF features with focal areas that showed malignant cholangiocarcinoma characteristics.

Background and aims. The first direct-acting antivirals (DAAs) to treat the viral hepatitis C (HCV) became available in 2011. Despite numerous clinical studies of patient outcomes after treatment, few have evaluated changes in the liver microenvironment. Despite achieving sustained virologic response (SVR), patients may still experience adverse outcomes like cirrhosis and hepatocellular carcinoma. By comparing gene and protein expression in liver biopsies collected before and after treatment, we sought to determine whether specific signatures correlated with disease progression and adverse clinical outcomes. Methods. Biopsies were collected from 22 patients before and after DAA treatment. We measured ∼770 genes and used multispectral imaging with custom machine learning algorithms to analyze phenotypes of intrahepatic macrophages (CD68, CD14, CD16, MAC387, CD163) and T cells (CD3, CD4, CD8, CD45, FoxP3). Results. Before DAA treatment, patients showed two distinct gene expression patterns: one with high pro-inflammatory and antiviral gene expression and another with weaker expression. Patients with adverse outcomes exhibited significantly (p<0.05) more inflammatory activity and had more advanced fibrosis stages in their baseline biopsies than those with liver disease resolution. Patients who achieved SVR had significantly decreased liver enzymes, reduced inflammatory scores, and restored type 1 interferon pathways similar to controls. However, after DAA treatment, patients with persistently high gene expression (67%, pre-hot) still had significantly worse outcomes (p<0.049) despite achieving SVR. A persistent lymphocytic infiltrate was observed in a subset of these patients (76.5%). After therapy, anti-inflammatory macrophages (CD16+, CD16+CD163+, CD16+CD68+) increased, and T cell heterogeneity was more pronounced, showing a predominance of helper and memory T cells (CD3+CD45RO+, CD4+CD45RO+, CD3+CD4+CD45RO+). Conclusions. Patients who have more inflamed livers and more advanced fibrosis before DAA treatment should be closely followed for the development of adverse outcomes, even after achieving SVR. We can enhance patient risk stratification by integrating gene and protein expression profiles with clinical data. This could identify those who may benefit from more intensive monitoring or alternative therapeutic approaches, inspiring a new era of personalized patient care. Lay Summary:Direct-acting antiviral (DAA) therapy has dramatically improved the treatment of chronic HCV, making it curable for most people. This study determined gene and protein expression differences in the liver before and after treatment of HCV. These results will lead to a deeper understanding of the changes in the hepatic immune microenvironment with and without the virus present in the liver in hopes of improving patient surveillance, prognosis, and outcome in the future.

BackgroundThe inflammatory macrophage response contributes to severe Ebola virus disease, with liver and lung injury in humans.ObjectiveWe sought to further define the activation status of hepatic and pulmonary macrophage populations in Ebola virus disease.MethodsWe compared liver and lung tissue from terminal Ebola virus (EBOV)-infected and uninfected control cynomolgus macaques challenged via the conjunctival route. Gene and protein expression was quantified using the nCounter and GeoMx Digital Spatial Profiling platforms. Macrophage phenotypes were further quantified by digital pathology analysis.ResultsHepatic macrophages in the EBOV-infected group demonstrated a mixed inflammatory/non-inflammatory profile, with upregulation of CD163 protein expression, associated with macrophage activation syndrome. Hepatic macrophages also showed differential expression of gene sets related to monocyte/macrophage differentiation, antigen presentation, and T cell activation, which were associated with decreased MHC-II allele expression. Moreover, hepatic macrophages had enriched expression of genes and proteins targetable with known immunomodulatory therapeutics, including S100A9, IDO1, and CTLA-4. No statistically significant differences in M1/M2 gene expression were observed in hepatic macrophages compared to controls. The significant changes that occurred in both the liver and lung were more pronounced in the liver.ConclusionThese data demonstrate that hepatic macrophages in terminal conjunctivally challenged cynomolgus macaques may express a unique inflammatory profile compared to other macaque models and that macrophage-related pharmacologically druggable targets are expressed in both the liver and the lung in Ebola virus disease.

Introduction: In renal transplantation, donor hepatitis C virus (HCV) status is crucial to consider when selecting a recipient given the high likelihood of transmission. We analyzed the effect of donor HCV status on post-renal transplant rejection and virologic infectious outcomes using electronic health record data from multiple US health care organizations. Methods: Using real world data from electronic health records of renal transplant recipients, a propensity score-matched case-control study of one-year renal transplant outcomes was conducted on cohorts of HCV-negative recipients who received an organ from an HCV-positive donor (HCV D+/R-) versus from an HCV-negative donor (HCV D-/R-). Donor HCV positivity was defined as new recipient HCV positivity within 30 days post-transplant. Cohorts were matched by major risk factors for rejection including age, gender, race, etiologies of end-stage renal disease, dialysis dependence, donor type, induction immunosuppression, and virologic lab studies. The primary outcome was one-year incidence of rejection. Secondary outcomes included longitudinal measures of liver and kidney function, incidence of non-HCV viremia, and DAA treatment pathways and responses. Results: Data from 900 renal transplant recipients were analyzed, 450 subjects per group (D+/R-, D-/R-). Mean age at transplant was 57.1 ± 11.9 years, 60 % were male, and 38 % were African American. Kaplan-Meier analysis showed a significantly increased incidence of one-year rejection for HCV D-/R- compared to HCV D+/R- (16.6% vs 22.8 %, p = 0.02). This difference did not persist on a sub-analysis excluding subjects with delayed graft function (DGF) (16.3% vs 19.2 %, p = 0.25). Although mean eGFR was initially higher in HCV D+/R-, there were no significant differences in liver or kidney allograft function at 12 months. There was no significant difference for composite viremia (CMV/EBV/BK; 37.66% vs 31.60 %, p = 0.07). The most common DAA regimen was glecaprevir/pibrentasvir (52.8 %). DAA treatment responses were excellent, with most subjects having a negative viral load by 90 days (mean: 1.7 ± 1.9 log units/mL). Conclusion: Donor HCV positivity did not negatively impact one-year rejection outcomes post-renal transplantation. Importantly, this effect was not biased by age. Anti-HCV treatment was effective and liver and kidney function were excellent at one-year post-transplant. These data support the continued expansion of the donor pool by utilizing organs from HCV-positive donors in the era of anti-HCV direct-acting antiviral therapies.

The gut microbiota drives progression to liver fibrosis, the main determinant of mortality in metabolic dysfunction-associated steatohepatitis (MASH). In this study, we aimed to identify bacterial species associated with protection against liver fibrosis in a high-risk population, and test their potential to protect against liver fibrosis in vivo. Based on stool shotgun metagenomic sequencing of 340 subjects from a population cohort disproportionally affected by MASH, we identified bacterial species from the Bacteroidales and Clostridiales orders associated with reduced risk of liver fibrosis. A bacterial consortium was subsequently tested in a mouse model of MASH, which demonstrated protective effects against liver fibrosis. Six of the eight inoculated bacteria were detected in mouse stool and liver. Intrahepatic presence of bacteria was further confirmed by bacterial culture of mouse liver tissue. Changes in liver histological parameters, gut functional profiles, and amino acid profiles were additionally assessed. Comparison between fibrosis-associated human metagenome and bacteria-induced metagenome changes in mice identified microbial functions likely to mediate the protective effect against liver fibrosis. Amino acid profiling confirmed an increase in cysteine synthase activity, associated with reduced fibrosis. Other microbiota-induced changes in amino acids associated with reduced fibrosis included increased gut asparaginase activity and decreased hepatic tryptophan-to-kynurenine conversion. This human-to-mouse study identified bacterial species and their effects on amino acid metabolism as innovative strategies to protect against liver fibrosis in MASH.

Steroids are widely used in maintenance immunosuppression treatment in kidney transplant recipients. Older individuals undergo age-related immunosenescence that consequently decreases their ability to process and evoke a response to foreign antigens. Thus, steroids may not be necessary in preventing allograft rejection and may consequently increase older recipients’ risk of long-term steroid-related adverse effects. The objective of this study was to analyze the adverse outcomes of long-term steroid immunosuppression in older kidney transplant recipients using real-world electronic medical record data. The TriNetX database “US Collaborative Network” was utilized to perform a propensity score-matched case-control study comparing 1-year, 3-year, and 5-year adverse effects of steroid immunosuppression in older adults (aged ≥ 65 years) kidney transplant recipients who underwent either an early-steroid withdrawal (ESW) maintenance regimen or a steroid continuous immunosuppression (SCI) regimen between 31 December, 2010 and 31 December, 2020. Early-steroid withdrawal was defined as tacrolimus plus mycophenolate mofetil maintenance with no prednisone after the seventh day post-transplant. Steroid continuous immunosuppression was defined as tacrolimus plus mycophenolate mofetil plus prednisone maintenance. Cohorts were matched on age, race/ethnicity, and risk factors for adverse steroid-related outcomes and rejection. Outcomes included post-transplant diabetes mellitus, dyslipidemia osteoporosis/fractures, myocardial infarction, glaucoma/cataract, stroke, pulmonary embolism, and malignancy. Secondary outcomes analyzed incidences of infection-related outcomes, graft-related outcomes, and recipient mortality. After matching, there were 304 recipients in each group (ESW, SCI). Mean age at the time of transplant was 69.2 ± 3.7 years (ESW) and 69.2 ± 3.4 years (SCI, p = 0.96). The Kaplan–Meier analysis showed recipients who underwent SCI had increased incidences of post-transplant diabetes mellitus at 1 year (22.36

Background & Aims:Clinical trials for reducing fibrosis in steatotic liver disease (SLD) have targeted macrophages with variable results. We evaluated intrahepatic macrophages in patients with SLD to determine if activity scores or fibrosis stages influenced phenotypes and expression of druggable targets, such as CCR2 and galectin-3. Methods:Liver biopsies from controls or patients with minimal or advanced fibrosis were subject to gene expression analysis using nCounter to determine differences in macrophage-related genes (n = 30). To investigate variability among individual patients, we compared additional biopsies by staining them with multiplex antibody panels (CD68/CD14/CD16/CD163/Mac387 or CD163/CCR2/galectin-3/Mac387) followed by spectral imaging and spatial analysis. Algorithms that utilize deep learning/artificial intelligence were applied to create cell cluster plots, phenotype profile maps, and to determine levels of protein expression (n = 34). Results:Several genes known to be pro-fibrotic (e.g. CD206, TREM2, CD163, and ARG1) showed either no significant differences or significantly decreased with advanced fibrosis. Although marked variability in gene expression was observed in individual patients with cirrhosis, several druggable targets and their ligands (e.g. CCR2, CCR5, CCL2, CCL5, and LGALS3) were significantly increased when compared to patients with minimal fibrosis. Antibody panels identified populations that were significantly increased (e.g. Mac387+), decreased (e.g. CD14+), or enriched (e.g. interactions of Mac387) in patients that had progression of disease or advanced fibrosis. Despite heterogeneity in patients with SLD, several macrophage phenotypes and druggable targets showed a positive correlation with increasing NAFLD activity scores and fibrosis stages. Conclusions:Patients with SLD have markedly varied macrophage- and druggable target-related gene and protein expression in their livers. Several patients had relatively high expression, while others were like controls. Overall, patients with more advanced disease had significantly higher expression of CCR2 and galectin-3 at both the gene and protein levels. Impact and implications:Appreciating individual differences within the hepatic microenvironment of patients with SLD may be paramount to developing effective treatments. These results may explain why such a small percentage of patients have responded to macrophage-targeting therapies and provide additional support for precision medicine-guided treatment of chronic liver diseases.