Donor lymphocyte transfusion for relapse after allogeneic bone marrow transplantation

Relapse of leukaemia after allogeneic bone marrow transplantation has a poor prognosis. In patients with recurrent chronic myelogenous leukaemia (CML) treatment with interferon a may induce haematological and cytogenetic remissions, but most remissions are of limited duration. Chimerism and transplantation tolerance toward the donor offer the possibility of adoptive immunotherapy using donor lymphocytes. We initiated the treatment of recurrent leukaemia by transfusing donor lymyhocytes into a CML patient. A complete remission was induced with the disappearance of Philadelphia chromosome positive cells and bcr-abl transcripts detected in polymerase chain reaction. In the meantime transfusion of donor lymphocytes has become the treatment of choice for recurrent leukaemia. Best results are obtained in patients with CML in cytogenetic or haematologic relapse, several months may be necessary for the achievement of molecular remissions. Complications of this treatment are graft versus host disease (GVHD) and marrow aplasia, mortality rates of 20% have been reported. Transfusion of donor marrow may rescue the patient from cytopenia. The rate of response increases with the degree of severity of GVHD, but responses are also observed in patients without GVHD. The role of interferon remains to be defined. Donor lymphocytes may induce remissions in acute myelogenous leukaemia, myelodysplastic syndromes, multiple myeloma, rarely in acute lymphoblastic leukaemia. Further attempts to improve anti leukaemic reactivity are discussed.