Post-transplant lymphoproliferative disease (PTLD) is currently the most serious and most commonly diagnosed complication after transplantation. It is characterized by high mortality - up to 80 percent in adult solid organ transplant patients and about 90 percent in patients after bone marrow transplantation. What are the causes of PTLD? How to recognize the symptoms of post-transplant lymphoproliferative disease and how is it treated?
Posttransplant lymphoproliferative disorder(post-transplant lymphoproliferative disorder -PTLD ) is currently the most serious and commoncomplication aftertransplant, both of solid organs (e.g. heart, kidneys) and bone marrow. The essence oflymphoproliferative syndromeis the uncontrolled multiplication (proliferation) of pathologically altered lymphocytes (most often B lymphocytes), which, with the simultaneous impairment of T-lymphocyte function caused by immunosuppressive treatment, attack internal organs and, consequently, lead to their failure and death.
Post-transplant lymphoproliferative disease - causes. Risk factors of PTLD
Transplant people take medications that weaken their immune system (inhibit the production of antibodies and immune cells) for the rest of their lives in order to minimize the risk of transplant rejection. However, long-term immunosuppression increases the risk of developing cancer. The most common cancers in organ and bone marrow recipients are skin cancer and post-transplant lymphoproliferative disease (PTLD), which usually takes the form of malignant lymphoma.
Malignant neoplasm is the result of rapid and uncontrolled multiplication of pathologically altered lymphocytes. The most common cause of this process is infection with the Epstein-Barr virus (EBV) - a carcinogenic herpes virus, which is one of the most common viruses in humans. He althy people usually pass the infection asymptomatically. In transplant recipients whose organism is weakened by immunosuppressive treatment, the virus attacks B lymphocytes and begins the process of their pathological transformation.
The risk of PTLDdepends on:
- type of organ transplanted - lymphoproliferative disease is most often diagnosed inpatients after intestinal transplantation (approx. 20%), followed by those after lung (4% -10%) and heart (1% -6%) or heart-lung transplant (2% -6%). Less frequently, the disease occurs in liver and kidney recipients (1-3%), and the least frequently in the bone marrow - 1%. (data:The Oncologist- journal of the Society for Translational Oncology)
- on the intensity of the applied immunosuppression
- Intensity of Graft versus Host Disease Prevention Therapy (GvHD)
- EBV infection type (primary or reactivation)
- donor (a transplant from an unrelated or partially compatible donor increases the risk of disease occurrence)
- of the patient's age (PTLD is most often diagnosed in children and the elderly).
Post-Transplant Lymphoproliferative Disease - Symptoms
The first symptoms of PTLD are non-specific and resemble those of a viral infection - there is fever, weakness, sweating and weight loss. You may notice enlarged lymph nodes, liver, and spleen. In the advanced stage of the disease, multi-organ failure occurs as a result of infiltration of organs by pathological lymphocytes. Symptoms of this may be gastrointestinal bleeding or pulmonary edema.
Symptoms of PTLD most often appear in the first year after transplantation, but in rare cases, they may appear up to the sixth year after transplantation.
Post-transplant lymphoproliferative disease - diagnosis
The basic examination is the histopathological examination of the affected organ. Confirmatory tests include flow cytometric immunophenotyping and quantification of EBV DNA copies in serum by PCR. Early detection of EBV allows a test aimed at assessing the activity of EBV replication.
Post-Transplant Lymphoproliferative Disease - Treatment
There is no uniform treatment regimen for PTLD. Doctors usually reduce the doses of immunosuppressive drugs used so far or replace them with other drugs. If there is no improvement, surgical excision of the neoplastic lesion, radiotherapy, antiviral therapy, combination therapy with chemotherapy, immunoglobulins, monoclonal antibodies (rituximab) or cytotoxic T lymphocytes are used.