Recombinant interleukin-2 (rIL-2) after autologous bone marrow transplantation (BMT): a pilot study in 19 patients

In vivo use of rIL-2 autologous BMT may be the means of reproducing a kind of "adoptive immunotherapy" from grafted cells after allogeneic BMT. This approach may enhance the spontaneous generation of cytotoxic T-cells and NK cells which are presumably involved in this immunotherapy. Potential risks of such an approach would be to increase the usual toxicity of rIL-2 and to jeopardize the hemopoietic reconstitution. To determine the feasibility of this approach we have treated 19 poor prognosis patients with a succession of autologous BMT followed 78 +/- 12 days later by a continuous infusion of rIL-2. Eighteen million international units (IU) per m2 per day of Proleukine (CETUS, Amsterdam, The Netherlands) were administrated over 6 or 12 days. No patient died of the procedure. Clinical toxicity related to rIL-2 was not increased. Hemopoietic toxicity, significant both for platelets and granulocytes, was transient. Immune stimulation was dramatic for lymphocytes and subpopulations (CD3+ and NK cells) and for cytolytic functions (NK and LAK activity). This trial establishes the feasibility of administration of high doses of rIL-2, 2 months after autologous BMT. In this setting a 6 day period of continuous infusion of 18 million per m2 per day of Proleukine appears to be a regularly tolerable dosage conducting to a major immune activation and invites further studies to determine the clinical impact of such an approach.