Apheresis in primary focal segmental glomerulosclerosis of native and transplanted kidneys: a therapeutic protocol.

BACKGROUND Patients with focal segmental glomerulosclerosis (FSGS) develop nephrotic syndrome and terminal renal failure in most cases. FSGS reappears in 15-50% of transplanted kidneys and frequently causes the graft loss. Sera from patients with FSGS of native or transplanted kidneys contain some proteinuric or permeability factors (PF) which can be removed by means of plasma exchange (PE) or protein A Immunoadsorption (IA). METHODS We suggest a therapeutic protocol, for patients with biopsy proven FSGS of native or transplanted kidneys, resistant to steroid and immunosuppressive therapy, based on the association of PE or IA to conventional drug therapy. Daily proteinuria, renal function, serum albumin and circulating level of proteinuric factors (permeability test) will be monitored at regular time intervals during the apheresis cycle, which will be intensive at the beginning (8-10 sessions in 4 weeks) and very gradually discontinued. Results. We will consider satisfactory remission the reduction of proteinuria below 1 g/day, improvement of renal function, normalization of serum albumin level (> 3.5 g/dl). Partial remission will be considered: proteinuria below 3 g/day, stable renal function, serum albumin level between 3 and 3.5 g/dl. Permeability test, if positive at baseline examination, should be negative after apheresis. CONCLUSIONS The primary endpoint of our protocol is: lasting remission (satisfactory or partial) after the apheresis suspension. Secondary endpoints are: maintained remission with continuing apheresis sessions, correlation between permeability activity and disease activity, identification of responders and non responders patients on the basis of positive permeability test.