Background: We describe a 1-year-old female who underwent living-related liver transplantation for biliary atresia and developed Epstein-Barr virus (EBV)-related posttransplant lymphoproliferative disorder. This disorder was resolved after withdrawal of immunosuppression therapy and administration of a high dose of acyclovir.
Methods: To quantify the extent of EBV activation and EBV load in peripheral blood, we measured the levels of EBV-infected peripheral lymphocytes by in situ hybridization (ISH) of EBV-encoded small mRNA 1 (EBER1).
Results: The decline in the number of EBER1-positive lymphocytes (from 362/50,000 mononuclear cells to 0/50,000) after treatment was in accord with the patient's clinical improvement.
Conclusions: This finding showed that quantitative analysis of EBV-infected peripheral lymphocytes by ISH of EBER1 is very useful for monitoring the EBV load and response to treatment of patients with EBV-related disorders. Furthermore, ISH may become an important tool for the early diagnosis and prevention of life-threatening posttransplant lymphoproliferative disorder in posttransplant patients.