The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.

Our findings implicate NETs in the protumorigenic inflammatory environment in NASH, suggesting that their elimination may reduce the progression of liver cancer in NASH. (Hepatology 2018).

We describe a new preservation modality combining machine perfusion (MP) at subnormothermic conditions (21°C) with a new hemoglobin‐based oxygen carrier (HBOC) solution. MP (n = 6) was compared to cold static preservation (CSP; n = 6) in porcine orthotopic liver transplants after 9 h of cold ischemia and 5‐day follow‐up. Recipients' peripheral blood, serial liver biopsies, preservation solutions and bile specimens were collected before, during and after liver preservation. Clinical laboratorial and histological analyses were performed in addition to mitochondrial functional assays, transcriptomic, metabolomic and inflammatory mediator analyses. Compared with CSP, MP animals had: (1) significantly higher survival (100% vs. 33%; p < 0.05); (2) superior graft function (p < 0.05); (3) eight times higher hepatic O2 delivery than O2 consumption (0.78 mL O2/g/h vs. 0.096 mL O2/g/h) during MP; and (4) significantly greater bile production (MP = 378.5 ± 179.7; CS = 151.6 ± 116.85). MP down‐regulated interferon (IFN)‐α and IFN‐γ in liver tissue. MP allografts cleared lactate, produced urea, sustained gluconeogenesis and produced hydrophilic bile after reperfusion. Enhanced oxygenation under subnormothermic conditions triggers regenerative and cell protective responses resulting in improved allograft function. MP at 21°C with the HBOC solution significantly improves liver preservation compared to CSP.

C4d-assisted recognition of antibody-mediated rejection (AMR) in formalin-fixed paraffin-embedded tissues (FFPE) from donor-specific antibody-positive (DSA+)renal allograft recipients prompted study of DSA+ liver allograft recipients as measured by lymphocytotoxic crossmatch (XM) and/or Luminex. XM results did not influence patient or allograft survival, or cellular rejection rates, but XM+ recipients received significantly more prophylactic steroids. Endothelial C4d staining strongly correlates with XM+ (<3 weeks posttransplantation) and DSA+ status and cellular rejection, but not with worse Banff grading or treatment response. Diffuse C4d staining, XM+, DSA+ and ABO-incompatibility status, histopathology and clinical-serologic profile helped establish an isolated AMR diagnosis in 5 of 100 (5%) XM+ and one ABO-incompatible, recipients. C4d staining later after transplantation was associated with rejection and nonrejection-related causes of allograft dysfunction in DSA-and DSA+ recipients, some of whom had good outcomes without additional therapy. Liver allograft FFPE C4d staining: (a) can help classify liver allograft dysfunction; (b) substantiates antibody contribution to rejection; (c) probably represents nonalloantibody insults and/or complete absorption in DSA-recipients and (d) alone, is an imperfect AMR marker needing correlation with routine histopathology, clinical and serologic profiles. Further study in late biopsies and other tissue markers of liver AMR with simultaneous DSA measurements are needed.

Histopathological parameters present in donor biopsies can independently predict post-transplant graft function. Implications for the pool of donor organs available for transplantation are discussed.