DNA fragmentation in childhood T-cell acute lymphoblastic leukaemia.

DNA isolated from 12 patients with childhood acute lymphoblastic leukaemia (T-ALL), analysed by gel electrophoresis exhibited a degradation pattern of increasing nucleosome repeat size, similar to that observed when nuclei from normal control cells are incubated with micrococcal nuclease. None of a group of adult T-ALL showed this fragmentation, nor was the pattern observed in normal control T-cells, cells from patients with a number of other forms of leukaemia, or in B-lymphoblastoid cells under the same incubation conditions. This phenomenon appears to be related to the changes in DNA that occur in glucocorticoid-induced cell death in mouse thymocytes, radiation-damaged spleen cells, and in cytotoxic T-cells deprived of interleukin 2. The method described here promises to be a reliable, simple approach to the characterization of T-ALL in childhood and may aid in the clinical management of this form of leukaemia.