STUDIES OF GLOMERULAR PERMEABILITY FACTORS DERIVED FROM T LYMPHOCYTE CULTURES IN PATIENTS WITH MINIMAL CHANGE NEPHROTIC SYNDROME

Abstract

In order to clarify glomerular permeability factors in minimal change nephrotic syndrome (MCNS), T cell-rich fractions were obtained from the peripheral blood of nine patients with MCNS and six healthy donors as controls. Each T cell-rich fraction was co-cultured with Concanavalin A, and the supernatants, which were rich in glomerular permeability factors, were collected after 48 hours of cultivation.Then, 2 ml of the supernatant was perfused into left renal artery of the anesthetized adult male Wistar rats for 30min. Urine samples were serially collected and their protein concentration were analyzed. This experiment revealed that urine protein excretion in the experimental animals increased during 12 hours after the renal perfusion of culture supernatants derived from MCNS patients. However, urine protein excretion was not increased in the control experiment. To determine the cause of increased glomerular permeability in experimental animals perfused with culture supernatants derived from MCNS, the animals were injected with polyethyleneimine (PEI) solution into the tail vein after the perfusion of supernatants. Electron microscopically, PEI-binding particles were counted in glomerular basement membrane (GBM). Compared with the control, PEI-binding particles were decreased in the lamina rara interna of glomeruli perfused with the supernatant derived from MCNS. The experimental result that supernatants derived from the T lymphocytes of MCNS patients decreased the negative charge of the GBM, resulting increased glomerular permeability, may suggest the pathogenesis of MCNS.