Elimination of acquired factor VIII antibodies by extracorporal antibody-based immunoadsorption (Ig-Therasorb).

Treatment of potent factor VIII antibodies is a difficult problem. In some cases a reduction of the antibody titer is necessary for effective treatment with human factor VIII concentrates. We describe a new method for extracorporal elimination of factor VIII antibodies (antibody-based immunoadsorption). Blood is drawn from an antecubital vein, citrated, and plasma is separated with a rotating membrane. Plasma passes alternately through one of two columns filled with sepharose-coupled polyclonal sheep antibodies to human immunoglobulins (Ig-Therasorb), whereas the other column is regenerated. Each cycle has a duration of 15 min. Three patients with high titer factor VIII antibodies (one hemophiliac and 2 with spontaneous antibodies; titers 29, 132, and 313 BU/ml, respectively) were treated. The average reduction of the antibody titer was 76.1 +/- 17.2% per session. In each patient 4 sessions were necessary to reduce the antibody titer to < 1 BU/ml. The mean processed plasma volume was 6731 +/- 640 ml and the mean duration of each session 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 procedure was tolerated without any side effects. Thus, rapid elimination of factor VIII inhibitors can be achieved with antibody-based immunoadsorption, which can be life-saving in some cases. This promising method should be evaluated in a larger number of patients.