Post-transplant lymphoproliferative disease

Post-transplant lymphoproliferative disease (PTLD) is a complication of transplantation in which there is uncontrolled growth of lymphocytes. It occurs in people whose immune systems have been intentionally suppressed due to having a solid organ transplant or hematopoietic stem cell transplant. The severity of PTLD can range from causing a mild, noncancerous (benign) overgrowth of tissue, to causing a life-threatening, cancerous (malignant) form of lymphoma. Common signs and symptoms are often vague, such as feeling unwell (malaise), fever, weight loss, night sweats, fatigue, and swollen lymph nodes. Additional symptoms depend on the organs or body part(s) affected. The digestive tract, central nervous system, and/or transplanted organ are often involved.

PTLD is often caused by Epstein-Barr virus (EBV), which infects lymphocytes called B-cells. Most people get EBV in childhood, but the virus becomes "inactive" because the immune system keeps it under control. In people with PTLD due to EBV, a weakened immune system may allow EBV to reactivate in infected B-cells, leading to their uncontrolled growth. In some cases, EBV from the transplant donor is reactivated in the recipient. PTLD can also occur if a recipient first becomes infected with EBV after the transplant. The reason that PTLD develops in people without EBV is not clear.

PTLD is diagnosed by immunophenotyping a biopsy of an involved lymph node or other affected tissue. Additional tests such as blood tests, imaging tests, or bone marrow biopsy may be needed to determine the location(s) and extent of the disease in the body.

Treatment recommendations may vary among people with PTLD but typically include lowering the dose of immunosuppresive drugs to allow the immune system to fight the EBV-infected cells. There are no therapies approved by the FDA to treat PTLD, but additional treatment options include using rituximab, surgery to remove affected tissue, radiation therapy, immunotherapy, and chemotherapy. Other treatments are being studied in clinical trials.