Specific removal of anti-A and anti-B antibodies using modified dialysis filters

Removal of anti-A and anti-B blood group antibodies from human blood has been shown to facilitate cross-matched kidney transplantation by preventing hyperacute rejection. Patients had anti-A and anti-B antibodies removed using plasmapheresis followed by immunoadsorption onto packed bead columns. The authors´ group conducted pilot studies to assess the feasibility of selectively removing anti-A and anti-B antibodies directly from blood using modified dialysis filters. An anti-A and anti-B specific antigen was covalently attached to the lumenal surface of hollow fibers within selected commercial dialysis modules. The filters were able to reduce the anti-A and anti-B filters of 300 ml of blood to 2 or below. A low molecular weight fraction of the authors´ antigen system was found to have no antibody binding capacity. The standard antigen was purified by removal of the low molecular weight fraction and a dialysis filter was modified using the purified antigen. This filter displayed a six-fold higher capacity than a dialysis filter modified with the same mass of standard antigen. Hence the authors expect that a dialysis filter modified with purified antigen at optimal antigen binding conditions may be able to significantly reduce the anti-A and anti-B filters of 2 L of blood. It is concluded that selective blood group antibody removal by antigen-modified dialysis filters is feasible and may be a simpler system than plasmapheresis followed by immunoadsorption