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

We have previously shown that lymphocytes from idiopathic minimal-lesi on nephrotic patients produce a lymphokine (supernatant factor) that i ncreases the (35)sulfate uptake in the glomerular basement membrane (G EM), The purpose of this report was to further characterize the supern atant factor by studying the effects of interleukins (IL) 2-4, 6, and 8, granulocyte-macrophage colony stimulating factor, and tumor necrosi s 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 co ntrol cultures: 10.8 +/- (SEM) 1.7 and 7.9 +/- 1.4 cpm/mu g GEM protei n, respectively (p < 0.005), IL-8 reproduces the effect of the reporte d supernatant factor on the GEM (35)sulfate uptake. Because IL-8 was d etected in the supernatant of peripheral mononuclear cell cultures fro m idiopathic minimal-lesion nephrotic syndrome patients in relapse and because the increased GEM (35)sulfate incorporation induced by the su pernatant factor has been abolished by the addition to the culture med ia of anti-IL-8 neutralizing antibodies, we postulate that IL-8 is the previously described supernatant factor.