Bone marrow transplantation from unrelated donors for patients with adult T-cell leukaemia/lymphoma.

Adult T-cell leukaemia/lymphoma (ATLL) is a highly aggressive haematological malignancy. More than 40 cases of ATLL treated by allogeneic bone marrow transplantation (BMT) from sibling donors have been reported, while there have been only a few cases of unrelated BMT for treatment of this disease. We began performing allogeneic BMT from unrelated donors in 1999 to improve the outcome of ATLL patients with no suitable sibling donors. Eight ATLL patients underwent unrelated BMT; five received the conventional conditioning regimen consisting of cyclophosphamide and total body irradiation, while three received a reduced-intensity preparative regimen. Two patients died due to encephalopathy of unknown aetiology on days 10 and 35, and one patient died due to progression of ATLL 25 months after BMT. Five patients are currently alive and disease-free at a median of 20 months after BMT. Proviral human T-lymphotropic virus type-I (HTLV-I) DNA load in peripheral blood mononuclear cells (PBMCs) was assessed in four cases before and after BMT. HTLV-I proviral DNA load was reduced significantly after transplantation. Unrelated BMT is feasible for treatment of ATLL. Further studies in a larger number of cases are required to determine the optimal conditioning regimen and stem cell source.