Recurrence of acute leukemia more than two years after allogeneic marrow grafting

The records of 232 patients with acute leukemia in continuous complete remission at two years after a marrow graft from genotypically or phenotypically HLA-identical family member were reviewed. With a followup time of 2-14.2 years, 17 patients have developed recurrent leukemia 2.0-6.3 years after grafting. No relapses have occurred beyond 6.3 years. Actuarial analysis shows a low but significant risk of recurrence of leukemia more than two years after grafting. These data suggest that the majority of the disease-free patients have had their original leukemic clone eliminated. It is important to study the leukemic cells in patients who suffer a relapse more than two years after grafting to determine whether the leukemia is of host or donor origin.