Adoptive immunotherapy for relapsed leukemia following allogeneic bone marrow transplantation.

Donor mononuclear cell (MNC) infusions provide a very potent and effective anti-leukemic therapy. For patient's with CML who relapse after allogeneic BMT, the administration of donor MNC can result in a direct GVL effect and re-establish sustained remissions, even when assessed by very sensitive PCR-based techniques. The GVL reaction appears to be most prominent in patients with chronic phase CML. It is less apparent for patients with more advanced stages of CML or for patients with relapsed acute leukemia and myelodysplasia, although only small numbers of these patients have been treated. While the majority of patients tolerate this therapy very well, treatment related morbidity and mortality is still quite significant, and efforts to limit the severity of GVHD, and to recognize and treat marrow aplasia early may be useful. Longer follow-up of patients who have achieved complete remission will be required to determine if this therapy will have an impact on long term disease free survival, but at the current time, it would seem to be a very acceptable alternative to a second BMT.