ELIMINATION OF ACQUIRED FACTOR-VIII ANTIBODIES BY EXTRACORPOREAL ANTIBODY-BASED IMMUNOADSORPTION (IG-THERASORB(R))

Treatment of potent factor VIII antibodies is a difficult problem. In some cases a reduction of the antibody titer is necessary for effectiv e treatment with human factor VIII concentrates. We describe a new met hod for extracorporal elimination of factor VIII antibodies (antibody- based immunoadsorption). Blood is drawn from an antecubital vein, citr ated, and plasma is separated with a rotating membrane. Plasma passes alternately through one of two columns filled with sepharose-coupled p olyclonal sheep antibodies to human immunoglobulins (Ig-Therasorb(R)), whereas the other column is regenerated. Each cycle has a duration of 15 min. Three patients with high titer factor VIII antibodies (one he mophiliac and 2 with spontaneous antibodies; titers 29, 132, and 313 B U/ml, respectively) were treated. The average reduction of the antibod y titer was 76.1 +/- 17.2% per session. In each patient 4 sessions wer e necessary to reduce the antibody titer to < 1 BU/ml. The mean proces sed plasma volume was 6731 +/- 640 ml and the mean duration of each se ssion 3.9 +/- 0.7 h. Serum IgG, IgA and IgM levels decreased by 75.3 /- 11.9%, 62.9 +/- 19.1%, and 54.8 +/- 23.8% respectively. The procedu re was tolerated without any side effects. Thus, rapid elimination of factor Vm inhibitors can be achieved with antibody-based immunoadsorpt ion, which can be lifesaving in some cases. This promising method shou ld be evaluated in a larger number of patients.