Effects of interleukin 7 on the growth of clonogenic cells in T-cell acute lymphoblastic leukaemia.

The effects of the recombinant human cytokines interleukin 2 (IL-2) and IL-7 on the proliferation of T-acute lymphoblastic leukaemia (T-ALL) cells were tested in a clonogenic assay. Highly purified leukaemic cells were obtained by immunomagnetic depletion of mature T cells and fluorescence-activated cell sorting for immature leucocyte markers (CD1, CD10, CD34). Of 9 cases tested, only 3 showed evidence of stimulation by cytokines. One was stimulated by both IL-2 and IL-7, one by IL-2 only, and the third by IL-7 alone. A further case showed proliferation without addition of cytokines. The remaining 5 cases were completely unresponsive. While both IL-2 and IL-7 are capable of stimulating leukaemic cells from some cases of T-ALL, the molecules regulating the proliferation of T-ALL cells in vitro remain to be more fully elucidated.