EFFECT OF LYMPHOKINES ON (35)SULFATE UPTAKE BY THE GLOMERULAR-BASEMENT-MEMBRANE

We have previously shown that lymphocytes from idiopathic minimal-lesion nephrotic patients produce a lymphokine (supernatant factor) that increases the (35)sulfate uptake in the glomerular basement membrane (GEM), The purpose of this report was to further characterize the supernatant factor by studying the effects of interleukins (IL) 2-4, 6, and 8, granulocyte-macrophage colony stimulating factor, and tumor necrosis factor on the (35)sulfate incorporation by rat glomeruli in vitro. A significant increase in GEM (35)sulfate uptake was only seen when the glomeruli were cultured with the addition of IL-8 as compared with control cultures: 10.8 +/- (SEM) 1.7 and 7.9 +/- 1.4 cpm/mu g GEM protein, respectively (p < 0.005), IL-8 reproduces the effect of the reported supernatant factor on the GEM (35)sulfate uptake. Because IL-8 was detected in the supernatant of peripheral mononuclear cell cultures from idiopathic minimal-lesion nephrotic syndrome patients in relapse and because the increased GEM (35)sulfate incorporation induced by the supernatant factor has been abolished by the addition to the culture media of anti-IL-8 neutralizing antibodies, we postulate that IL-8 is the previously described supernatant factor.