In vivo biological response following low-dose interleukin-2 in complete remission B-cell non-Hodgkin's lymphoma patients

The aim of the present study is to verify whether recombinant interleukin-2 (rIL-2) at low doses is well tolerated in aggressive lymphoma in complete remission (CR), and if there may be a biological justification for its use as a remission-maintenance therapy able to reduce the percentage of relapses. We treated 6 patients with B-cell non-Hodgkin's lymphoma (B-NHL) in CR following PM-Cytabom with rIL-2 3 IMU s.c. x 5 d per wk, every other wk for 8 wk. Our results show that this treatment provokes statistically significant changes in the absolute number of lymphocytes, eosinophils, CD25 + and CD122 + cells and soluble IL-2 receptors ; these doses, however, are not sufficient to modify CD3 + , CD16 + and CD56 + cell values or natural killer and lymphokine activated killer cell activity. Thus these findings do not appear to constitute a biological rationale for the use of rIL-2 at this dose and schedule as a remission-maintenance therapy in B-cell NHL. Nevertheless, the results are a valid basis for further study of the use of the same rIL-2 doses for a longer period of time in combination with other cytokines, in the hope that the biological effects can be augmented without increasing the toxic side effects.