Loss of glomerular polyanion in vitro induced by mononuclear blood cells from patients with minimal-change nephrotic syndrome.

Peripheral mononuclear blood cells isolated from nephrotic subjects with minimal-change nephrotic syndrome (selective proteinuria greater than 3.5 g/24 h) or various other forms of glomerulonephritis (non-selective proteinuria greater than 3.5 g/24 h) were stimulated with concanavalin A and cultured for 20 h in the presence of kidney tissue under standard conditions. Identical cultures were developed with phosphate-buffered saline from normal control donors. Triplicate cultures of each subject (3 X 10(6) cells/ml) were incubated with or without 5, 10, or 20 micrograms/ml concanavalin A per milliliter serum-free tissue culture medium upon cryostat sections from normal rat kidney. The cells were subsequently removed, and the tissue sections were washed and stained for sialoprotein using the colloidal iron method and evaluated for stainability of glomerular polyanion using light microscopy. The results show that peripheral mononuclear blood cells from subjects with minimal-change nephrotic syndrome had affected glomerular polyanion in vitro during incubation with kidney tissue in a significantly (p less than or equal to 0.005) higher number of cases (15/17) as compared with the number of glomerulonephritis patients who scored positive in 4 out of 14 cases, whereas this was the case in 3 out of 18 cases of the normal donors. It is concluded that stimulated cellular immune reactivity of peripheral mononuclear blood cells from subjects with minimal-change nephrotic syndrome in vitro is associated with the potential impairment in vitro of an important part of the glomerular filtration barrier. Since this cellular activity occurred to a significant lesser extent in other nephrotic subjects, this response is not related to the nephrotic state per se.