Recurrent focal glomerulosclerosis: natural course and treatment with plasma exchange.

BACKGROUND: Focal glomerulosclerosis (FGS) can recur after renal transplantation and prognosis is poor in untreated patients. A circulating plasma factor has been implicated in the pathogenesis of a recurrent FGS and treatment with plasma exchange has proven effective in decreasing proteinuria in some patients. METHODS: We retrospectively studied the course of disease in patients with recurrent FGS, transplanted in our centre. Seven patients transplanted between 1991 and 1997, received treatment with plasma exchange, whereas 10 patients, transplanted between 1973 and 1991, were left untreated and served as historical controls. RESULTS: The time of onset of proteinuria (>3.5 g/day) was comparable in the untreated and treated patients (9 and 10 days respectively), as was the average proteinuria at that time (5.5 and 5.8 g/day respectively). In the untreated patients, proteinuria persisted and eventually all grafts were lost, on average 43 months after the diagnosis of a recurrence. In five cases (50%) the recurrence was the single cause of graft loss. The clinical course was different in the seven patients who were treated with plasma exchange. In five of these patients, the recurrence occurred within 3 weeks after transplantation. Plasma exchange was started 1-14 days after onset of proteinuria in these patients. Two lost their grafts after 0.7 and 1.0 months because of untreatable rejection. In the remaining three patients the plasma exchange resulted in abrupt disappearance of the proteinuria, and the response has been lasting for 2-3.2 years. In these patients the only histological abnormality was foot effacement on electron-microscopy. In two patients the recurrence became manifest at 9 weeks and 5.8 years after transplantation respectively. These two patients relapsed after the initial course of plasma exchange, but responded to repeated session, and are currently being treated once a month. They have been followed for 1. 7 and 1.4 years after the onset of proteinuria and their urinary protein levels are 0.23 and 1.2 g/10 mmol creatinine. CONCLUSIONS: The prognosis of untreated recurrent FGS is poor. Treatment with plasma exchange can lead to complete remission of proteinuria and relapsing patients may respond to repeated sessions. Best results are obtained when plasma exchange is started early, when there are no visible lesions on light-microscopy.