Antibody-mediated rejection without elevated anti-blood type antibody after ABO-incompatible living donor liver transplantation: a case report.

The incidence of antibody-mediated rejection (AMR) following ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) has decreased since the introduction of rituximab. However, the prognosis is extremely poor once AMR develops. Therefore, perioperative monitoring of anti-blood type antibody titers is important. Here, we report a rare case of ABO-I LDLT that developed AMR without elevated anti-blood type antibody titers. The patient was a 65-year-old man (Type A +) who underwent ABO-I LDLT for alcoholic cirrhosis using a liver right-lobe graft from a 60-year-old woman (Type B +). Rituximab was administered preoperatively. On postoperative day (POD) 5, the portal blood flow decreased drastically. Liver biopsy showed AMR, although there was no increase in the anti-blood type B antibody titer. This resulted in a delay in the diagnosis and treatment of AMR. Steroid pulse therapy, high-dose intravenous immunoglobulin, and plasma exchange were immediately performed. However, the patient developed prolonged graft dysfunction and died on POD40. The pathological findings at autopsy revealed a diagnosis of hepatic veno-occlusive disease. This case suggests that a method other than anti-blood type antibodies should be developed for early diagnosis of AMR.