IMMUNOHISTOLOGICAL REACTIVITY PATTERN OF THE ANTI-CUTANEOUS T-CELL LYMPHOMA ANTIBODY BE2

It has been reported that the monoclonal antibody BE2, raised against leukaemic T cells, reacts specifically with [human] malignant lymphoid cells and represents a valuable reagent for the early identification of cutaneous T-cell lymphomas. To test this hypothesis, a comprehensive range of nodal and cutaneous biopsies have been examined immunohistologicaly using single and double immunoenzymatic and immunofluorescent staining methods. BE2 showed a broad range of reactivity, consistently labelling normal endothelial cells, B-lymphocytes in mantle and marginal zones, T-lymphocytes in the paracortex of lymph nodes and medulla of thymus, as well as a variety of different macrophage types, including Langerhans cells and dermal macrophages. Furthermore, although BE2-positive T-lymphocytes were most frequent in malignant lymphomas, they were also found in four of 19 benign dermatoses. We conclude that BE2 is neither T-cell nor tumour-cell specific, and that use of this reagent on tissue sections is unlikely to improve the diagnosis of cutaneous lymphomas.