Presence of antibody to A- and B-transferases in minor incompatible bone marrow transplant.

The contribution of the bone marrow to plasma A- or B-transferase activities has been studied in patients who underwent incompatible bone marrow transplantation (BMT). As deduced from major incompatibility (group O recipient/A donor), the contribution of the marrow to these plasma activities was c. 5-10% of the total activity. In cases of minor incompatible transplants (A recipient/O donor), normal plasma activity was present in two patients, while no activity was found in a further two in whom a potent antitransferase was detected. The antibody inhibited both A- and B-transferase activities to a high titre. The patients in whom this antibody arose exhibited severe graft-versus-host disease.