T-Cell-Rich Large-B-Cell Lymphomas Contain Non-Activated CD8 + Cytolytic T Cells, Show Increased Tumor Cell Apoptosis, and Have Lower Bcl-2 Expression Than Diffuse Large-B-Cell Lymphomas

The factor(s) responsible for the reduced B cell number and increased T cell infiltrate in T-cell-rich large-B-cell lymphomas (TCRBCLs) have not been well characterized. We studied 18 TCRBCLs and 12 diffuse large-B-cell lymphomas (DLBCLs) to compare the 1) predominant T cell subpopulation(s), 2) expression of cytotoxic granule proteins (TIA-1 and granzyme B), 3) level of tumor cell apoptosis (Apoptag system, Oncor, Gaithersburg, MD), and 4) expression of Ki-67 (Mib-1) and apoptosis-related proteins (fas (CD95), bcl-2, and p53). T cells in TCRBCLs and DLBCLs were predominantly CD8 + T cells expressing αβ T-cell receptors and TIA-1 (16 of 18 TCRBCLs with >50% TIA-1 + small lymphocytes) but lacking granzyme B (16 of 18 TCRBCLs with