Lymphoproliferative disorders in cardiac transplant recipients are multiclonal lymphomas.

Tissue specimens from 5 immunosuppressed cardiac transplant recipients with lymphoproliferative disorders were examined for rearrangements in immunoglobulin DNA. In each case DNA analysis of tissues obtained from several sites or at various times showed different clonal immunoglobulin gene rearrangements for each of the three immunoglobulin gene loci. These findings indicate that lymphoproliferative disorders in immunosuppressed cardiac transplant recipients represent multiclonal or oligoclonal B cell lymphomas.