EFFECT OF LIPOID NEPHROSIS CYTOKINE ON GLOMERULAR SULFATED COMPOUNDS AND ALBUMINURIA

Supernatants from peripheral blood mononuclear cells cultures of 30 id iopathic, minimal lesion, nephrotic syndrome (IMLNS) patients in relap se and the same patients in remission were fractionated by gel filtrat ion chromatography. Fractions eluting with carbonic anhydrase (29 kilo daltons) were infused for 5 days at the rate of 10 mu l/h into the lef t renal artery of Wistar rats using an Alter osmotic pump. On the last day of infusion, rats were injected with (35)sulfate (1.0 mCi/200 g) intraperitoneally and killed after 8 h. Glomeruli were isolated and gl omerular basement membrane (GEM) obtained. There was a significant inc rease in (35)sulfate uptake by GEM of the infused kidney (302 +/- 92 c pm/mg dry glomerular weight, mean +/- SEM) compared with the uptake se en in the contralateral kidney (157 +/- 36, P < 0.01) when the fractio n from IMLNS patients in relapse was infused. No significant differenc es in (35)sulfate incorporation were seen between infused kidney (166 +/- 41) and contralateral kidney (172 +/- 64) when the same fraction f rom patients in remission was administered. A significant increase in albuminuria was seen on the last day of infusion (14.2 +/- 1.0 mg/24 h , mean +/- SEM) when supernatant factor from IMLNS patients in relapse was used. No significant differences in urinary albumin excretion pri or to and after infusion were seen when the same fraction from IMLNS p atients in remission was administered. The in vivo infusion of superna tant factor from IMLNS patients in relapse increased the (35)sulfate u ptake by GEM and augmented albuminuria, suggesting that the factor may have pathogenic significance in the proteinuria of IMLNS.