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Abstract Reliable and available non-invasive methods for hepatic fibrosis assessment are important in chronic liver disease (CLD). Our aim was to compare stepwise algorithms combining standard ultrasound with serum markers and transient elastography (TE) for detecting advanced fibrosis (F3-4) and cirrhosis. Retrospective single center study between 2012 and 2018 of CLD patients with biopsy, TE, blood tests, and liver ultrasound parameters of surface nodularity (SN), lobar redistribution, and hepatic vein nodularity. Our cohort included 157 patients (51.6% males), mean age 47.6 years, predominantly non-alcoholic fatty liver disease and viral hepatitis (61%), with F3-4 prevalence of 60.5%. Area under the curve for F3-4 was 0.89 for TE ≥ 9.6 kPa and 0.80 for FIB-4 > 3.25. In multivariate modeling, TE ≥ 9.6 kPa (OR 21.78) and SN (OR 3.81) had independent association with F3-4; SN (OR 5.89) and TE ≥ 10.2 kPa (OR 15.73) were independently associated with cirrhosis. Two stepwise approaches included FIB-4 followed by SN or TE; sensitivity and specificity of stepwise SN were 0.65 and 1.00, and 0.89 and 0.33 for TE ≥ 9.6 kPa, respectively. Ultrasound SN and TE were independently predictive of F3-4 and cirrhosis in our cohort. FIB-4 followed by SN had high specificity for F3-4.

The development of single cell RNA sequencing technologies has been instrumental in advancing our understanding of tissue biology. Here, MacParland et al. performed single cell RNA sequencing of human liver samples, and identify distinct populations of intrahepatic macrophages that may play specific roles in liver disease.

Mounting effective innate and adaptive immune responses are critical for viral clearance and the generation of long lasting immunity. It is known that production of inhibitory factors may result in the inability of the host to clear viruses, resulting in chronic viral persistence. Fibrinogen-like protein 2 (FGL2) has been identified as a novel effector molecule of CD4(+)CD25(+) Foxp3(+) regulatory T (Treg) cells that inhibits immune activity by binding to FCγRIIB expressed primarily on antigen presenting cells (APC). In this study, we show that infection of mice with Lymphocytic Choriomeningitis Virus WE (LCMV WE) leads to increased plasma levels of FGL2, which were detected as early as 2 days post-infection (pi) and persisted until day 50 pi. Mice deficient in FGL2 (fgl2(-/-)) had increased viral titers of LCMV WE in the liver early p.i but cleared the virus by day 12 similar to wild type mice. Dendritic cells (DC) isolated from the spleens of LCMV WE infected fgl2(-/-) had increased expression of the DC maturation markers CD80 and MHC Class II compared to wild type (fgl2(+/+)). Frequencies of CD8(+) and CD4(+) T cells producing IFNγ in response to ex vivo peptide re-stimulation isolated from the spleen and lymph nodes were also increased in LCMV WE infected fgl2(-/-) mice. Increased frequencies of CD8(+) T cells specific for LCMV tetramers GP33 and NP396 were detected within the liver of fgl2(-/-) mice. Plasma from fgl2(-/-) mice contained higher titers of total and neutralizing anti-LCMV antibody. Enhanced anti-viral immunity in fgl2(-/-) mice was associated with increased levels of serum alanine transaminase (ALT), hepatic necrosis and inflammation following LCMV WE infection. These data demonstrate that targeting FGL2 leads to early increased viral replication but enhanced anti-viral adaptive T & B cell responses. Targeting FGL2 may enhance the efficacy of current anti-viral therapies for hepatotropic viruses.

TCRαβ(+) CD4(-)CD8(-)NK(-) double negative T cells (DN T cells) can act as regulatory T cells to inhibit allograft rejection and autoimmunity. Their role in graft-versus-host disease and mechanisms of suppression remain elusive. In this study, we demonstrate that DN T cells can inhibit CD4(+) T cell-mediated GVHD in a semi-allogeneic model of bone marrow transplantation. Furthermore, we present evidence of a novel autocrine IFNγ signaling pathway in Fas-deficient C57BL/6.lpr (B6.lpr) DN T cells. B6.lpr DN T cells lacking IFNγ or its receptor were impaired in their ability to suppress syngeneic CD4(+) T cells responding to alloantigen stimulation both in vitro and in vivo. Autocrine IFNγ signaling was required for sustained B6.lpr DN T cell IFNγ secretion in vivo and for upregulation of surface Fas ligand expression during TCR stimulation. Fas ligand (FasL) expression by B6.lpr DN T cells permitted lysis of activated CD4(+) T cells and was required for suppression of GVHD. Collectively, our data indicate that DN T cells can inhibit GVHD and that IFNγ plays a critical autocrine role in controlling the regulatory function of B6.lpr DN T cells.

Xenografting primary human solid tumor tissue into immunodeficient mice is a widely used tool in studies of human cancer biology; however, care must be taken to prove that the tumors obtained recapitulate parent tissue. We xenografted primary human hepatocellular carcinoma (HCC) tumor fragments or bulk tumor cell suspensions into immunodeficient mice. We unexpectedly observed that 11 of 21 xenografts generated from 16 independent patient samples resembled lymphoid neoplasms rather than HCC. Immunohistochemistry and flow cytometry analyses revealed that the lymphoid neoplasms were comprised of cells expressing human CD45 and CD19/20, consistent with human B lymphocytes. In situ hybridization was strongly positive for Epstein-Barr virus (EBV) encoded RNA. Genomic analysis revealed unique monoclonal or oligoclonal immunoglobulin heavy chain gene rearrangements in each B-cell neoplasm. These data demonstrate that the lymphoid neoplasms were EBV-associated human B-cell lymphomas. Analogous to EBV-associated lymphoproliferative disorders in immunocompromised humans, the human lymphomas in these HCC xenografts likely developed from reactivation of latent EBV in intratumoral passenger B lymphocytes following their xenotransplantation into immunodeficient recipient mice. Given the high prevalence of latent EBV infection in humans and the universal presence of B lymphocytes in solid tumors, this potentially confounding process represents an important pitfall of human solid tumor xenografting. This phenomenon can be recognized and avoided by routine phenotyping of primary tumors and xenografts with human leukocyte markers, and provides a compelling biological rationale for exclusion of these cells from human solid tumor xenotransplantation assays.