[The spectrum of lymphoproliferations and malignant lymphoma after organ transplant]. / Das Spektrum lymphoproliferativer Erkrankungen und maligner Lymphome nach Organtransplantation.

Lymphoproliferative disease in patients with organ transplantation has increasingly been diagnosed in recent years. It is caused by immunosuppression after organ transplantion. A large percentage of these tumors is associated with Epstein-Barr virus infection. The classification differentiates between early lesions, polymorphic and monomorphic lymphoproliferations. Whereas the early lesions are often polyclonal, the remaining groups are mostly monoclonal. Polymorphic lymphoproliferative disease shows a wide spectrum of B-cell differentiation, whereas monomorphic proliferations resemble sproadic malignant lymphomas. The latter also show genetic abberations of the c-myc-, Ras-, p53- and Bcl6-genes. With reference to the germinal center reaction, posttransplant lymphoproliferations have to be assigned to the post-follicular activated B-cell type. While until 1991 only 2% of the cases of PTLD had an EBV-association, the EBV-associated PTLD have been frequently observed in recent times and presently constitute about 20% of the cases. EBV-negative PTLD constitute a negative prognostic factor. Posttransplant lymphomas might also represent a model for sporadic lymphoproliferative disease, that for example also occurs at elderly patients.