[T-cell leukemias of adulthood]

9 adult patients suffering from different forms of T-cell-malignancies were investigated: 4 patients with T-ALL; 1-T-ALL-CLL mixed form (prolymphocytic); 2 T-CLL; 2 Sézary-syndrome. The clinical peculiarities of the different forms of leukemias were compared: involvement of lymph nodes and spleen, of the central nervous system and the skin was frequent; in contrast to the findings in Sézary-syndrome, bone marrow infiltration was prominent. Light and electron microscopic morphology of the malignant cells are described. In all cases a strong activity of acid phosphatase was demonstrated, in one patient prominent deposits of glycogen. The T-cell-quality of the respective malignant cell population as well as the B-T-cell distribution of the remaining "normal" lymphocytes were shown by the following cell markers: demonstration of T-cell-antigen, resp. membrane immunoglobulins with the aid of specific heterologous antisera conjugated with peroxidase, 125iodine or fluoresceine; complement consumtion or cytotoxicity with such antisera; spontaneous rosette formation with sheep red cells or with acrylic acid beads. Usually, there was a good coincidence in results obtained with the different markers. In two patients, however, T-cells demonstrated by anti-T-globulin were not able to form T-rosettes. Responsiveness of the malignant T-cells and also of the remaining "normal" blood lymphocytes to different mitogens usually was depressed, immunoglobulin levels in the blood mostly were normal. Taking all findings into consideration, T-cell-leukemias of the adult represent a special group of hematological malignancies; the different subgroups show similarities; transitional forms occur.