Chronic T lymphocytic leukaemia: antigenic, morphological and functional properties of the neoplastic lymphocytes.

We describe 2 cases of T cell leukaemia. Both patients react with OKT 4 monoclonal antibody, while their clinical course, surface markers and in vitro immunological reactivity present opposite behaviour. The cells of 1 patient react with all pan T cell markers (OKT 3, OKT 11, Leu 1), from E and Ea rosettes and respond well to mitogens. This patient does not present liver, spleen or lymph node enlargement; white cell count is stable and no other haematological alterations are present. The cells from the 2 patient are unreactive with OKT 3 and are unable to form Ea rosettes. The response to mitogens is almost abolished. The disease has an aggressive clinical course with progressively increasing blood leucocyte count and infiltration of liver and spleen. These data suggest that the study of antigenic and functional properties of T CLL may be useful to better define the biologic characteristics and the prognostic criteria of the disease.