Summary
Treatment of potent factor VIII antibodies is a difficult problem. In some cases a
reduction ofthe antibody titer is necessary for effective treatment with human factor
VIII concentrates. We describe a new method for extracorporal eliminationof 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-Therasorb00), 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 lifesaving in some cases. This promising method should be evaluated in a larger
number of patients.