Allogeneic bone marrow transplantation for adult leukaemia with soy bean lectin fractionated marrow

A heterogeneous group of 11 consecutive patients with leukaemia have been transplanted successfully with allogeneic marrow depleted of T lymphocytes by soy bean lectin agglutination and neuraminidase-treated sheep erythrocyte rosetting. Effective depletion was achieved, leaving less than 1% of donor T lymphocytes. Despite the small numbers of nucleated cells infused (mean 0.14 X 10(8)/kg) there was only moderately delayed recovery of peripheral blood counts and no graft failures have occurred. Standard methotrexate prophylaxis against graft-versus-host disease (GVHD) was also employed in the first four transplants. Only one case of mild grade I (skin only) acute GVHD has occurred and there has been no chronic GVHD to date. The group of patients show an actuarial cumulative survival of 55% with two early infective deaths (days 42 and 44 post-transplant) and three late deaths, two with leukaemic relapse and the third with probable viral encephalitis. The longest survivor is now 1109 days post-transplant. This series indicates that lectin fractionation of donor marrow, previously employed mainly in children, can also be effective in minimizing GVHD in adults without endangering successful engraftment.