Abnormal proliferation of T-colony-forming cells from peripheral blood of patients with T-cell acute lymphoblastic leukaemias and lymphomas in complete remission: potential prognostic value.

Peripheral blood T-colony-forming cells (T-CFC) from most patients with T-cell acute lymphoblastic leukaemias (T-ALL) and T-cell non-Hodgkin's lymphomas (T-NHL), can proliferate in vitro in methylcellulose in the absence of added growth factors or mitogens. We now report that spontaneous T-cell colonies could also be obtained during complete remission of 13 out of 21 patients with T-ALL and T-NHL, but none of eight patients with common (pre-B) ALL (cALL). Colony cells were mainly E+T3+, with a variable expression of other T cell markers. Spontaneous T-CFC did not possess self-renewal capacity in the absence of added growth factors. Moreover, incubation of spontaneous colonies with colchicine yielded mitoses in only two out of seven patients, with one normal and one abnormal karyotype. In five patients tested, recombinant interleukin 2 (IL2) could also induce the proliferation of some T-CFC. Both spontaneous and IL2-induced colonies were inhibited by an anti-IL2 receptor monoclonal antibody, suggesting that interaction of IL2 with its receptor may be involved in the proliferation of some T-CFC from these patients. A study of 14 T-ALL patients tested during their first remission indicated that patients who developed no or few spontaneous colonies during their first remission (less than 20 colonies/10(5) mononuclear cells) seemed to relapse later and to have a significantly longer survival than patients with a high number of spontaneous colonies. These data suggest that the spontaneous proliferation capacity of T-CFC might be of prognostic value in the clinical evaluation of T-ALL.