From the Guidelines
Blood tests for diagnosing Post-Transplant Lymphoproliferative Disorder (PTLD) primarily focus on detecting Epstein-Barr virus (EBV) through quantitative EBV PCR, which measures viral DNA levels in the blood, as recommended by the Sixth European Conference on Infections in Leukemia (ECIL-6) guidelines 1. The main test is quantitative EBV PCR, which measures viral DNA levels in the blood. Regular monitoring of EBV viral load is recommended for transplant recipients, especially those at high risk (EBV-negative recipients with EBV-positive donors) 1. Other helpful blood tests include:
- Complete blood count to check for abnormal lymphocytes
- Lactate dehydrogenase (LDH) which is often elevated in lymphoproliferative disorders
- Liver function tests which may show abnormalities if the liver is involved While these blood tests are valuable for screening and monitoring, they cannot definitively diagnose PTLD. A tissue biopsy remains the gold standard for confirmation, as it allows pathologists to examine the tissue architecture and perform immunohistochemistry to classify the specific type of PTLD, as outlined in the ECIL-6 guidelines 1. Early detection through regular blood monitoring is crucial as it allows for preemptive reduction of immunosuppression or antiviral therapy before PTLD fully develops. The diagnosis of EBV-PTLD can be established on a proven or probable level, with probable EBV disease characterized by significant lymphadenopathy, hepatosplenomegaly, or other end-organ manifestations, together with significant EBV DNA-emia 1.
From the Research
Diagnosis of PTLD
- The diagnosis of post-transplant lymphoproliferative disorder (PTLD) is typically made by a tissue biopsy, such as a lymph node biopsy, gastric ulcer biopsy, or tonsillar biopsy 2.
- The World Health Organization (WHO) pathology classification of a tissue biopsy remains the gold standard for PTLD diagnosis 3.
- Blood tests, such as EBV DNA measurement in peripheral blood, can be used to monitor for EBV infection and potentially detect PTLD early 3, 4.
- However, there is no specific blood test that can definitively diagnose PTLD, and a tissue biopsy is often necessary to confirm the diagnosis.
Role of EBV in PTLD Diagnosis
- Epstein-Barr virus (EBV) infection is a major risk factor for PTLD, and many cases of PTLD are associated with EBV infection 2, 3, 5, 4, 6.
- EBV DNA measurement in peripheral blood can be used to monitor for EBV infection and potentially detect PTLD early 3, 4.
- Latent membrane protein (LMP) or Epstein-Barr encoded RNA (EBER) staining can be used to document EBV infection in tissue biopsies 2.
Treatment and Prevention of PTLD
- Reduction in immunosuppression (RIS) is the best validated intervention for preventing PTLD 3.
- Rituximab, a humanized monoclonal antibody against CD20, is an effective treatment for CD20+ PTLD 2, 3, 5, 6.
- Chemotherapy, such as R-CHOP, may be effective for treating patients with rituximab-resistant EBV-PTLD 5.
- Antiviral prophylaxis may not have a significant effect on the occurrence of PTLD, but rituximab induction treatment may be associated with a reduced risk of PTLD 6.