Supernatant factor from peripheral blood mononuclear cell (PBMC) cultu
res of idiopathic minimal lesion nephrotic syndrome (IMLNS) patients i
n relapse induces in vivo albuminuria and increases (35)sulfate uptake
by glomerular basement membrane (GBM) in rats. The purpose of this st
udy was to evaluate the effect of anti-interleukin 8 (IL8) neutralizin
g antibody on the effects induced by the supernatant factor. Supernata
nt factor col lected from six cultures of PBMC from IMLNS patients in
relapse were combined and aliquoted into two samples. Anti-IL8 neutral
izing antibody (750 ng) was added to one. Supernatant factor or supern
atant factor and anti-IL8 antibody were infused for 5 days into the le
ft renal artery of Wistar rats using an osmotic pump. On the last day
of infusion, rats were injected with (35)sulfate (1.0 mCi/200 g) intra
peritoneally and killed after 8 h. Glomeruli were isolated and GEM obt
ained. There was a significant increase in (35)sulfate uptake of the i
nfused kidney (169 +/- 52 cpm/mg dry glomerular weight, mean +/- SEM)
compared with the uptake seen in the contralateral kidney (116 +/- 41,
P < 0.05) when the supernatant factor was infused alone. No significa
nt differences in (35)sulfate incorporation were seen between infused
kidney (173 +/- 5) and contralateral kidney (190 +/- 49) when supernat
ant factor and anti-IL8 antibody were administered. A significant incr
ease in albuminuria was seen on the last day of infusion (0.43 +/- 0.1
1 albumin/ creatinine ratio, mean) SEM) compared with the ratio prior
to infusion of the supernatant factor alone (0.18 +/- 0.03, P <0.05).
No significant differences in urinary albumin/creatinine ratios prior
to and on the 5th day of infusion were seen when the supernatant facto
r was administered with anti-IL8 antibody. Supernatant factor effects
were abolished by the addition of anti-IL8 neutralizing antibody, sugg
esting that the described effects are mediated by IL8.