T-CELL RECEPTOR EXPRESSION IN THE T-CELL MALIGNANCIES

Twenty-eight cases with T-cell neoplasms (10 with T-cell acute lymphoblastic leukemia [T-ALL], 10 with T-lymphoblastic lymphoma, and 8 with peripheral T-cell lymphomas) and 2 cases with reactive lymph nodes were immunohistochemically stained with monoclonal antibodies βF1, δTCS1, and WT31; βF1 antibody recognizes the β-subunit of T-cell receptor (TCR), whereas δTCS1 and WT31 recognize the δ- and αβ-subunits of TCR, respectively. Five cases with T-ALL, four with T-lymphoblastic lymphoma (T-LL), and seven with peripheral T-cell lymphomas were positive for βF1. None showed positive reactivity for δTCS1. One case with T-LL and four cases with peripheral T-cell lymphomas were positive for WT31. Of the nine cases positive for βF1 amont T-ALLs and T-LLs, six were also positive for CD1 (OKT6), whereas six of seven positive cases for CD1 were positive for βF1. The authors therefore suggest that TCRβ is expressed in the immature T-cells just earlier than or around the same stage of differentiation as those expressing CD1. The authors' immuno-electron microscopy study revealed that positive reactivity for βF1 was localized predominantly in the cytoplasm of the neoplastic cells in the cases with T-ALL, T-LL and peripheral T-cell lymphomas, and in the cytoplasm of the reactive T-cells. However, it was not localized on the surface membrane. In contrast, positive reactivity for WT31 was localized on the surface membrane of the neoplastic and reactive T-cells. Only half of the cases of peripheral T-cell lymphomas showed positive reactivity for WT31. The authors consider that it may not be a very useful antibody for the detection of TCRαβ on the T-cell neoplasms using frozen tissue sections.