Graft‐Versus‐Tumor Effect in Major Histocompatibility Complex–Mismatched Mouse Liver Transplantation

Liver transplantation (LT) is currently considered an important method in treating hepatocellular carcinoma (HCC) and an alternative treatment for other liver malignancies. Here, we demonstrated that the graft‐versus‐tumor (GVT) effect exists in allogeneic liver transplantation (allo LT). Recipient‐derived T cells played a critical role in the GVT process of allo LT, as demonstrated by extensive infiltration and significant activation of recipient T cells in the tumor after surgery. Moreover, this process was related to donor‐derived T/B cells by improving the immune microenvironment in the tumor, as demonstrated by elevated levels of interferon‐γ (IFN‐γ), tumor necrosis factor‐α (TNF‐α), interleukin‐2 (IL‐2), IL‐6, IL‐16, chemokine (C‐X‐C motif) ligand 10 (CXCL10), and CXCL11 and decreased levels of IL‐10 and IL‐4 at tumor sites. Additionally, tacrolimus (FK506) treatment inhibited the GVT effect on allo LT. Donor liver‐derived T/B cells infiltrate extrahepatic tumors to trigger a strong T‐cell‐mediated immune response and thus improve the tumor immune microenvironment.