[Cells in the epidermotropic lymphomas (mycosis fungoides and Sézary syndrome. Study using monoclonal antibodies].

The phenotypic expression of immunocompetent cells involved in lesions of cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome) was studied by using monoclonal antibodies specific for T-cell subsets and HLA DR antigens (OKT3, T4, T6, T8) (BL6, BL2). In Sezary syndrome, the phenotype of Sezary cell is homogeneous (T3+, T4+, T8-, T6-, BL2-) and corresponds to the phenotype expressed by the normal helper T-cell population. At ultrastructural level, the discontinuous distribution of OKT4 and OKT3 antigenic sites on the cell surface is similar to the HTLA antigens. In skin lesions, the Langerhans cells expressed two specificities shared by normal thymocytes (T6 and BL6). The tumoral lymphoid cells infiltrating the skin showed the same phenotype (helper type) as the circulating Sezary cells (T3+, T4+, T8-, T6-). Moreover, the T3+ cells also expressed HLA DR antigens and corresponded to activated T-lymphocytes. These results led us to the conclusion that the epidermotropic cutaneous T cell lymphoma represent a homogeneous expression of helper T-cells and could be included in the helper cell neoplasms.