Immunoadsorption for removal of anti-A and anti-B blood group antibodies in ABO-incompatible bone marrow transplantation.

About 10-15 percent of all patients undergoing allogeneic bone marrow transplantation have a major ABO-incompatibility with their donors. The risk of acute hemolytic reactions due to the infusion of an incompatible donor marrow into the recipient can basically be prevented by recipient antibody depletion or by donor marrow red cell depletion. Nine patients were treated by immunoadsorption using a cartridge with chemically synthesized human blood group A and B antigen as immunoadsorbent for antibody depletion. Within a four-hour-procedure about 2-4 times the patient plasma volume could be processed, thus lowering the anti-A and -B hemagglutinins by 2 to 3 tubes. There was a tendency of better IgG removal when titers initially were high, showing a high antibody clearing capacity. There was no significant correlation between starting titer or amount of plasma volume processed and titer reduction. No decrease in titers were observed in one case. We propose repeated immunoadsorption procedures over 2-3 consecutive days before BMT. The procedure is largely safe and without serious side effects. A major advantage is the avoidance of nonautologous human blood products compared to the conventional plasma exchange. All 8 patients surviving long enough had prompt and stable engraftment of all three cell lines post BMT. No late serological complications occurred when patients were regularly monitored and in vivo adsorption was used when titers increased.