Intraperitoneal infusion of interleukin-2 in patients with malignant ascites: Phenotypic and functional effects on tumor-associated lymphocytes

The aim of the present study was to evaluate the effects of intraperitoneal interleukin-2 (IL-2) infusion on tumor-associated lymphocytes (TAL) and peripheral blood lymphocytes (PBL) in patients with malignant ascites. Six patients were given IL-2 daily for 14 days by intraperitoneal infusion using a delivery system. TAL were isolated from the ascitic fluid before (day 0) and 7 and 14 days after the initiation of the treatment. Although no variations were observed in cytolytic activity and surface markers of PBL, TAL showed an important increase in the percentage of cells expressing IL-2 receptors of lymphokine-activated killer (LAK)-l antigen (i.e., a surface molecule expressed by human LAK cells and their precursors). Perhaps more importantly, a sharp increase of natural killer activity and the de novo generation of LAK activity were also observed.