In vitro and in vivo cytogenetic effects of recombinant interleukin-2 on human lymphocytes

To determine the cytogenetic effects of rIL-2, we investigated the rIL-2-induced sister chromatid exchange (SCE) and chromosomal aberrations in human peripheral lymphocytes in vitro and in patients given rIL-2 as a 24-hour infusion for 28 consecutive days. No significant increase in SCE frequency and chromosomal aberrations was observed after in vitro incubation of lymphocytes with 100 U/ml of rIL-2. A daily rIL-2 dose of 6.6 x 10(5) U/m2 did not induce any significant effect on SCE frequency and chromosomal aberrations while a marked increase was observed in the percentage of IL-2 receptor positive cells and HLA-DR positive cells. Although IL-2 therapy is only in developmental stage, our results suggest there is little or no potential mutagenic and/or carcinogenic hazard with this agent.