Characterization of postcardiac transplant lymphomas. Histology, immunophenotyping, immunohistochemistry, and gene rearrangement.

Objective: Between 2% and 9% of cardiac transplant recipients develop posttransplant lymphoproliferative disease, which includes lymphomas. These are usually aggressive Epstein-Barr virus-associated B-cell proliferations similar to those seen in other immunodeficiency states. A retrospective pathologic study of the tumor tissue from 21 cardiac transplant recipients with posttransplant lymphoproliferative disease was undertaken.

Design: Tumor histology, immunohistochemistry, immunophenotyping, and DNA analysis for clonal gene rearrangement and the presence of Epstein-Barr virus DNA were performed.

Patients: The mean patient age was 53.4 +/- 10.2 years (range 33-67 years); 33% of the patients were alive at the time of study.

Results: Histologically, the samples comprised one Burkitt's lymphoma, three diffuse mixed lymphomas, eight diffuse large-cell lymphomas, and nine immunoblastic lymphomas. Thirteen (93%) of 14 samples were infiltrated by small reactive T cells; five of the lymphomas qualified as T-cell rich. Of 14 cases studied, 12 had clonal immunoglobulin gene rearrangements, 1 had oligoclonal bands, and 1 exhibited only a germline pattern. The B cells were CD10+, CD19+, and CD20+, and the reactive T cells were CD2+, CD3+, CD5+, CD7+, CD8+, and CD57+ by immunophenotyping.

Conclusions: In this patient series, morphologically aggressive lymphomas and disseminated disease occurred early as well as late after transplantation. Most of the tumors showed a reactive T-cell component, which may represent a host attempt at controlling the B-cell proliferation.