Human recombinant interleukin-2 provokes infiltration of lymphocytes into myocardium and liver in rabbits.

Treatment with human recombinant interleukin-2 (rIL-2) is associated with multiple organ dysfunctions, including hepatic and cardiac toxicities. We present a rabbit model that may be highly suited to investigations of these organ toxicities. Rabbits were treated with rIL-2 at a dose of 3 x 10(6) Cetus units/kg/day in divided doses every 8 h for 9-11 doses. Control animals received either excipient or 5% dextrose in water. Treatment with rIL-2 resulted in hepatic and myocardial infiltration by lymphocytes and mononuclear cells. Monoclonal antibody-staining techniques revealed a high percentage of T lymphocytes. It remains to be shown whether these infiltrates are responsible for the respective organ toxicities or represent merely an epiphenomenon of rIL-2 treatment.