Background/Aims: Allogeneic recognition of donor cells by host T lymphocytes requires the expression of cytokine-dependent molecules, such as class II major histocompatibility antigens, intracellular adhesion molecule 1 (ICAM-1), and lymphocyte function-associated antigen 3 (LFA-3). In the liver, activation of Kupffer cells after ischemic injury during the transplantation procedure may result in an early induction of cytokinedependent molecules. Methods: The pattern of induction of ICAM-1, HLA-DR, HLA-DQ, and LFA-3 was investigated in 30 postreperfusion surgical biopsy specimens of liver allografts by an immunohistochemical technique. Results: Two patterns of induction were observed: focal or diffuse. On hepatocytes, ICAM-1 was induced in 22 cases (11 focal, 11 diffuse), HLA-DR in 18 cases (13 focal, 5 diffuse), HLA-DQ in 13 cases (3 focal, 10 diffuse), and LFA-3 in 1 case (focal). On bile duct cells, HLA-DR was expressed in 19 cases, associated with HLA-DQ in 7 cases. No induction of ICAM-1 and LFA-3 was detected. Compared with the other patients, the group of patients with diffuse postoperative hepatocellular induction of ICAM-1 was characterized by higher preharvesting serum transaminase levels in the donor (P ≤ 0.001), suggestive of preoperative ischemic injury, and increased incidence of acute graft rejection (P = 0.04). Conclusions: Preoperative warm ischemia may modify the immunogenicity of liver allografts.