ADOPTIVE IMMUNOTHERAPY FOR RELAPSE OF CHRONIC MYELOID-LEUKEMIA AFTER ALLOGENEIC BONE-MARROW TRANSPLANT - EQUAL EFFICACY OF LYMPHOCYTES FROMSIBLING AND MATCHED UNRELATED DONORS

Lymphocyte transfusion from the marrow donor (DLT) is well established as an effective therapy for relapse of CML post allogeneic BMT, Repor ts thus far have been mostly limited to patients who received DLT from a matched sibling donor. We compared the efficacy and toxicity of DLT in 30 patients who were treated with cells from their HLA-identical s ibling (n = 18) or from their phenotypically HLA-matched unrelated mar row donor (n = 12), The overall probability of obtaining a cytogenetic remission was 69% (95%CI: 51-83%) and was not significantly different between the two groups. The disease stage at the time of DLT was the only factor associated with cytogenetic remission by multivariate anal ysis; patients treated in cytogenetic or molecular relapse (n = 11) we re seven times more likely (RR = 7.4 95%CI: 2.4-22.4, P = 0.0005) to r espond compared to patients treated for hematologic relapse (n = 19), There was a trend towards more acute GVHD II-IV in the unrelated donor group (58 vs 39%, P = 0.09), but the probability of developing extens ive chronic GVHD was not significantly different (56 vs 39%, P = 0.4), We conclude that transfusion of donor cells from HLA-matched voluntee r donors does not appreciably increase the risk of GVHD compared with transfusion of cells from HLA-identical siblings in patients with CML who relapse following allogeneic BMT, Conversely, there is no evidence for an increased graft-versus-leukemia effect after DLT from voluntee r donors.