Adjuvant interleukin-2 therapy for patients refractory to donor lymphocyte infusions

Objective Donor lymphocyte infusions (DLI) can induce durable second remissions in patients relapsed after allogeneic stem cell transplantation (SCT) for hematologic malignancies. However, some patients are refractory or respond only partially to DLI. Recombinant interleukin-2 (IL-2) can increase the anti-leukemic activity of donor lymphocytes and has previously been reported as a potential enhancer of DLI. We assessed the response to adjuvant IL-2 on relapsed SCT who had failed to respond to DLI alone. Patients and methods A total of 13 patients (8 with CML, 2 with AML, 2 with MM, 1 with NHL) relapsed after SCT and were treated with DLI. All had achieved only partial or no response after DLI. Recombinant IL-2 was thereafter administered. Results Five patients achieved a CR and four a PR after DLI/IL-2 therapy. Those achieving a CR appeared to have a survival advantage compared to partial or nonresponders. The IL-2 was well tolerated; the most frequent side effects were fever (100%), lethargy (69%), and anorexia and vomiting (31%). Five patients experienced graft-vs-host disease (grade II–IV) after the treatment. Conclusions IL-2 increases the response rate with improved survival in a proportion of patients who relapse after allo-SCT and do not respond well to DLI alone. There is no major toxicity. It may therefore be valuable as adjuvant therapy in conjunction with DLI.