Autologous Organoid‐T Cell Co‐Culture Platform for Modeling of Immune‐Mediated Drug‐Induced Liver Injury

A matrix‐free human liver organoid–T cell co‐culture platform enables modeling of immune‐mediated drug‐induced liver injury (iDILI). Using flucloxacillin and patient‐matched cells, this system recapitulates HLA‐B*57:01–restricted CD8⁺ T cell activation and hepatocyte damage. By linking genetic risk to immune function, this approach enables mechanistic dissection and functional prediction of idiosyncratic hepatotoxicity in vitro. Abstract Modeling adaptive immune responses in induced pluripotent stem cell (iPSC)‐derived liver systems remains a critical barrier for studying immune‐mediated hepatic diseases, including idiosyncratic drug‐induced liver injury (iDILI). Conventional hepatotoxicity models lack the components required to capture patient‐specific, T cell‐mediated injury. Here, a scalable and matrix‐free human liver organoid (HLO) microarray platform is presented that enables controlled co‐culture of Human Leukocyte Antigen (HLA)‐genotyped, iPSC‐derived HLOs with autologous CD8⁺ T cells. This immune‐competent system supports antigen‐specific T cell activation and reproduces cytotoxic effector responses in a genetically defined context. As a proof‐of‐concept, the platform models clinically relevant iDILI caused by flucloxacillin in HLA‐B*57:01 carriers, recapitulating CD8⁺ T cell proliferation, hepatocyte apoptosis, and variability in immune responses across donors. The system captures hallmark features of adaptive immune‐mediated hepatotoxicity, including secretion of tumor necrosis factor‐alpha and Granzyme B, and cytokeratin‐18 release from injured hepatocytes. By linking genetic susceptibility with functional immune outcomes, this platform provides a modular and scalable approach for evaluating immune‐mediated toxicities. The method offers broad utility for mechanistic studies of drug hypersensitivity, immune‐related adverse events, and preclinical safety assessment in support of precision medicine. A matrix-free human liver organoid–T cell co-culture platform enables modeling of immune-mediated drug-induced liver injury (iDILI). Using flucloxacillin and patient-matched cells, this system recapitulates HLA-B*57:01–restricted CD8⁺ T cell activation and hepatocyte damage. By linking genetic risk to immune function, this approach enables mechanistic dissection and functional prediction of idiosyncratic hepatotoxicity in vitro. Abstract Modeling adaptive immune responses in induced pluripotent stem cell (iPSC)-derived liver systems remains a critical barrier for studying immune-mediated hepatic diseases, including idiosyncratic drug-induced liver injury (iDILI). Conventional hepatotoxicity models lack the components required to capture patient-specific, T cell-mediated injury. Here, a scalable and matrix-free human liver organoid (HLO) microarray platform is presented that enables controlled co-culture of Human Leukocyte Antigen (HLA)-genotyped, iPSC-derived HLOs with autologous CD8⁺ T cells. This immune-competent system supports antigen-specific T cell activation and reproduces cytotoxic effector responses in a genetically defined context. As a proof-of-concept, the platform models clinically relevant iDILI caused by flucloxacillin in HLA-B*57:01 carriers, recapitulating CD8⁺ T cell proliferation, hepatocyte apoptosis, and variability in immune responses across donors. The system captures hallmark features of adaptive immune-mediated hepatotoxicity, including secretion of tumor necrosis factor-alpha and Granzyme B, and cytokeratin-18 release from injured hepatocytes. By linking genetic susceptibility with functional immune outcomes, this platform provides a modular and scalable approach for evaluating immune-mediated toxicities. The method offers broad utility for mechanistic studies of drug hypersensitivity, immune-related adverse events, and preclinical safety assessment in support of precision medicine. Advanced Science, Volume 12, Issue 43, November 20, 2025.