CIRCULATING FACTOR ASSOCIATED WITH INCREASED GLOMERULAR-PERMEABILITY TO ALBUMIN IN RECURRENT FOCAL SEGMENTAL GLOMERULOSCLEROSIS

Background, Heavy proteinuria and progressive renal injury recur after transplantation in up to 40 percent of patients with renal failure ca used by idiopathic focal segmental glomerulosclerosis. A circulating f actor may be responsible for this recurrence. Methods. To determine wh ether patients with focal segmental glomerulosclerosis have a circulat ing factor capable of causing glomerular injury, we tested serum sampl es from 100 patients with the disorder in an in vitro assay of glomeru lar permeability to albumin. Of the 56 patients who had undergone rena l transplantation, 33 had recurrences, Sixty-four patients, many of wh om had undergone transplantation, were being treated with dialysis. Th irty-one patients with other renal diseases and nine normal subjects w ere also studied, Results. The 33 patients with recurrent focal segmen tal glomerulosclerosis after transplantation had a higher mean (+/-SE) value for permeability to albumin (0.47+/-0.06) than the normal subje cts (0.06+/-0.07) or the patients who did not have recurrences (0.14+/ -0.06), After plasmapheresis in six patients with recurrences, the per meability was reduced (from 0.79+/-0.06 to 0.10+/-0.05, P=0.008), and proteinuria was significantly decreased, Patients with corticosteroid- sensitive nephrotic syndrome or with membranous nephropathy after tran splantation had low levels of serum activity. The circulating factor b ound to protein A and hydrophobic-interaction columns and had an appar ent molecular mass of about 50 kd. Conclusions, A circulating factor f ound in some patients with focal segmental glomerulosclerosis is assoc iated with recurrent disease after renal transplantation and may be re sponsible for initiating the renal injury.