ROLE OF ALLOGENEIC BONE-MARROW TRANSPLANTATION FROM AN HLA-IDENTICAL SIBLING OR A MATCHED UNRELATED DONOR IN THE TREATMENT OF CHILDREN WITHJUVENILE CHRONIC MYELOID-LEUKEMIA

Seven children (age range 1.8-11 years) with juvenile chronic myelomon ocytic leukaemia (JCML) received an allogeneic bone marrow transplanta tion (BMT), four from an HLA-identical sibling and three from a matche d unrelated donor. In the four children transplanted using an HLA-iden tical sibling, conditioning regimen included busulfan (BU), cyclophosp hamide (CY) and melphalan (L-PAM), whereas: graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine-A (Cs-A). The preparative regimen was well tolerated and all patients engrafted promptly. None of the patients have relapsed and all four children remain in haematol ogical remission after an observation time of 7,24,25 and 48 months, r espectively. Of the three children given BMT from an unrelated volunte er, one was < 2 years of age and she received the BU/CY/L-PAM regimen. In view of the increased risk of graft rejection described in patient s transplanted from unrelated donors, we chose to prepare the other tw o patients with fractionated total body irradiation (TBI), thiotepa an d CY. Cs-A, short-term methotrexate and Campath-1G in vivo were employ ed to prevent GVHD in this group of patients. Graft failure with autol ogous reconstitution of haemopoiesis occurred in the child given the c hemotherapy-based regimen. One of the two girls given TBI relapsed aft er BMT; therefore only one of the three patients who received a marrow transplant from a matched unrelated donor survives in complete haemat ological remission 10 months after BMT. Our study suggests that the co nditioning regimen we employed for allogeneic BMT from a compatible si bling is an effective means of eradicating the leukaemic clone. In our experience, results obtained using unrelated donors are less satisfac tory and, at present, the use of such donors seems to be riskier and a ssociated with a lower success rate as compared with BMT from an HLA-i dentical sibling.