[In vitro effects of GH and IGF-1 on natural cytostatic activity]

We previously reported that natural cytotoxicity, mediated by Natural Killer (NK) cells, is low in GH-deficient children and increases up to normal levels after a long-term treatment. In order to investigate the role of GH and IGF1 on the restoration of this immune function, we studied the in vitro effect of increasing doses of biosynthetic GH and IGF1 on NK activity of GH-deficient children. No variations of NK activity were observed after incubation of GH-deficient children's cells in the presence of GH as well as IGF1. Our data suggest the effect of GH and IGF1 on NK activity not to be direct, but mediated by unidentified factors.