The role of soluble inflammatory mediators in the wound healing process is under investigation. Interleukin 2 (IL2), an immune modulator produced by T lymphocytes, was tested in vitro for its effects on human diploid fibroblasts. Human diploid fibroblasts (1.0 x 10(4)) were incubated for 24 hours in Alpha minimal essential media (Gibco Laboratories, Gaithersburg, Md.) at 37 degrees C in 5% CO2 in air with 500 U/ml of IL2 (Cetus Corp., Emeryville, Calif.). Cells were then pulsed with 3 mu Ci/ml of tritiated thymidine overnight. The mean increase in the incorporation of tritiated thymidine of the cells treated with IL2 over control cells was 38% (p value less than 0.05). Interleukin 2 has a significant effect on the metabolism of human dermal fibroblasts and may accelerate the wound healing process.