To elucidate the mechanism of immunologic abnormalities induced by surgical trauma, we measured interleukin 2 (IL-2) production and IL-2 receptor expression in peripheral blood mononuclear cells from 16 patients with cholelithiasis. Compared with preoperative levels, IL-2 production and IL-2 receptor expression were significantly reduced on postoperative day 4, and the reduction was consistent with the suppression of lymphocyte proliferative response to phytohemagglutinin.