Lymphoproliferative disorders in renal transplant patients in Japan

Post-transplantation lymphoproliferative disorders (PT-LPD) are characterized by a clinically and morphologically heterogeneous group of lymphoid proliferation occurring after organ or bone marrow transplantation. The immunodeficient state provides a basis for lymphomagenesis probably through activation of oncogenic viruses. Twenty-four patients in whom PT-LPD developed after renal transplantation in Japan were analyzed. They received hemodialysis for 4 to 226 (median 13) months before transplantation. In situ hybridization was performed to detect Epstein-Barr virus (EBV). Polymerase chain reaction and Southern hybridization with primers in the tax and pol regions of human T-cell leukemia virus type I (HTLV-1) were performed on DNA extracted from paraffin-embedded specimens. Immunohistochemical analysis revealed that 12 cases were B-cell type, 10 cases (42%) T-cell type and 2 NK-cell type. Five of the T-cell cases were classified as adult T-cell lymphoma with proven HTLV-1 genome in the tumor and seropositivity for the virus. These cases were classified as adult T-cell lymphoma (ALT). More than 80% of B-cell, 30% of T-cell and both NK/T-cell lymphomas were EBV-positive. Co-infection of EBV and HTLV-1 was found in 2 cases with ATL. These findings showed that ATL is common among Japanese renal transplant patients, which might be due to transmission of HTLV-1 via blood transfusion during hemodialysis.