Abstract: 【Abstract】 Objective Compared with plasma exchange, double-filtration plasmapheresis (DFPP) needs only small amount of plasma or albumin. But the efficiency and safety of DFPP in treating anti-GBM disease was unclear. Patients and methods There were 8 patients admitted to this hospital in 2008 with the diagnosis of anti-GBM disease confirmed by serological and renal pathological examinations. All patients were treated with immunosuppressive agents as well as DFPP therapy daily or once every other day. OP-08W plasma separators and EC-20W or EC-30W plasma fractionators (Asahi, Japan) were used. One to one and a half of calculated plasma volume was processed in each session. Serum anti-GBM antibodies were detected by an ELISA test kit (Euroimmun). Serum total IgG, plasma albumin and fibrinogen were measured. Results We totally performed 53 DFPP sessions, with 4-9 sessions for each patient. The average plasma volume being exchanged was 1.26±0.14 times of the calculated body plasma volume. The initial levels of anti-GBM antibodies were 159.94±67.02 RU/ml (82 to 262 RU/ml). The levels of anti-GBM antibodies after DFPP sessions decreased in a liner manner despite the difference of initial levels among patients, with the slope rate from -16.3 RU/ml/session to -29.9 RU/ml/session and the average slope -20.27±1.10 RU/ml/session. Serum albumin dropped significantly after each session using plasma as replacement fluid, but remained unchanged in sessions using 8% albumin solutions. Serum IgG dropped in an exponential way. Plasma fibrinogen decreased 49.5±8.9% after each session. Conclusions Combined with immunosuppressive therapy, DFPP efficiently removed anti-GBM antibodies in this study. Anti-GBM antibodies dropped in a similar rate among patients, suggesting the possibility for physicians to estimate the total sessions needed to reach the target of negative anti-GBM test. High concentration of albumin solution can be used for the compensation of albumin loss during the therapy. Because plasma fibrinogen levels decreased obviously after DFPP, invasive procedure should be performed with caution.

Key words: Double-filtration plasmapheresis, Anti-glomerular basement membrane antibody, Anti-glomerular basement membrane disease