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

Abstract

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