Operative stress potentiates the inductivity of membrane associated lymphotoxin (mLT) on lymphokine activated killer (LAK) cells in vitro.

Membrane-associated lymphotoxin (mLT) is induced in human peripheral blood mononuclear cells when cultured with interleukin 2, in the form of lymphokine-activated killer (LAK) cells. The inductivity of mLT is thought to be dependent upon the differentiation potential of LAK cell precursors, being T cells and natural killer cells. In this study, we investigated the inductivity of mLT on LAK cells from surgical patients. The preoperative values of mLT inductivity were found to be generally higher in malignant than benign cases, and the postoperative time course of mLT inductivity showed a transient decrease immediately after the operation followed by gradual increase over 2 weeks. Moreover, patients with an intraoperative bleeding volume of more than 1,000 ml showed a delay in the postoperative increase of mLT inductivity. These data suggest that operative stress potentiates the inductivity of mLT on LAK cells; however, excess stress may cause a delay in the restoration of mLT inductivity.