Production of fibrogenic cytokines by interleukin-2-treated peripheral blood leukocytes: expression of transforming growth factor-beta and platelet-derived growth factor B chain genes.

Abstract

To assess the production of fibrogenic cytokines by interleukin-2 (IL-2)-stimulated peripheral blood leukocytes and to examine their ability to stimulate the production of connective tissue. Culture medium from human peripheral blood leukocytes incubated with or without IL-2 was tested for induction of fibroblast proliferation, collagen synthesis, and expression of cytokine genes. Supernatants from IL-2-treated peripheral blood leukocytes induced six times more fibroblast proliferation than medium from leukocytes cultured without IL-2. The expression of type I procollagen and fibronectin messenger RNAs was increased in human fibroblasts in response to leukocyte supernatants. Unstimulated leukocytes expressed minimal levels of transforming growth factor-beta or platelet-derived growth factor B chain messenger RNAs, but could be greatly enhanced by IL-2 treatment. Mediators that induce connective tissue production are secreted by IL-2-treated peripheral blood leukocytes. These cytokines may be responsible, in part, for the stimulation of abdominal adhesions in patients receiving intraperitoneal immunotherapy.