Impact of post-transplant flow cytometric panel-reactive antibodies on late-onset hepatic venous outflow obstruction following pediatric living donor liver transplantation.

The development of late-onset hepatic venous outflow obstruction (LOHVOO) following pediatric living donor liver transplantation (LDLT) can lead to uncontrollable fibrotic damage in liver grafts, even long-term patency of the graft outflow is achieved with appropriate therapeutic modalities. The aim of this study was to verify our hypothesis that some immunological responses, particularly cellular and/or antibody-mediated rejection (AMR), are associated with LOHVOO, which occurs following damage to liver sinusoidal endothelial cells in zone 3 of liver grafts. One hundred and eighty-nine patients underwent LDLT between May 2001 and December 2010 at our institute. Nine patients (4.8%) were identified as having LOHVOO. The preoperative factors, operative factors, and mortality, morbidity, and survival rates were examined and compared between the groups with and without LOHVOO. No statistical differences were observed between the groups with regard to preoperative factors, technical factors, or postoperative complications. However, FlowPRA reactivity was found to be a statistically significant risk factor for LOHVOO (P=0.006). The patients with both class I- and class II-reactive antibodies also had a significant risk of developing LOHVOO (P=0.03) and exhibited significantly higher retransplant rates. In conclusion, although further studies are needed to clarify this phenomenon, the pathophysiological mechanism underlying the development of LOHVOO after LDLT may be explained by immune-mediated responses that facilitate damage in zone 3 of liver grafts.