SUBCUTANEOUS VERSUS INTRAVENOUS LOW-DOSE IL-2 THERAPY AFTER AUTOLOGOUS TRANSPLANTATION - RESULTS OF A PROSPECTIVE, NONRANDOMIZED STUDY

Use of IL-2 therapy after autologous transplantation is currently bein g explored to reduce relapse rate, Low doses of the cytokine induce si gnificant immunomodulation avoiding the severe side-effects associated with high-dose IL-2 therapy, However, low-dose IL-2 is usually given by continuous infusion through central venous lines with the consequen t risks of thrombosis and infections, Twenty-six consecutive patients who received autologous transplants received low-dose IL-2 after stabl e engraftment had been achieved, The first 13 patients (group A) were scheduled to receive 400 000/IU/m(2)/day for 3 months by continuous in travenous infusion, Ten of these patients suffered infectious episodes , mainly bacteriemias that often necessitated delaying IL-2 therapy (m edian delivered dose: 32% of planned), The next 13 patients were then assigned to receive IL-2 (800 000-1 000 000 IU/m(2)/day for 3 months) subcutaneously (group B), For group B patients, median dose intensity was 84% (P = 0.01 when compared with group A patients), Only one sever e infectious episode was observed in these patients, Clinical toxicity in group B patients consisted mainly of s.c. nodules, Immunomodulatio n, measured as an increase in the absolute number of CD56(+) cells and CD56(+bright) cells, was higher in patients who received the cytokine by the subcutaneous route (median peak increase of CD56(+) cells: 160 and 220% for group A and B patients respectively; median peak increas e of CD56(+bright) cells: 210% and 310% for group A and B respectively , P < 0.05 between groups A and B), No statistically significant incre ment of T lymphocytes was observed in any group, No hematologic toxici ty was observed apart from eosinophilia, which was very marked in grou p B (P < 0.01), Our results show that low-dose s.c. IL-2 therapy is as sociated with low clinical and hematologic toxicity after autologous t ransplantation. The immunomodulation achieved is no less than that ach ieved with the i.v. approach.