Graft-versus-leukemia-induced complete remission following unrelated umbilical cord blood transplantation for acute leukemia

A 15-year-old female received an unrelated three of six HLA antigen matched umbilical cord blood (UCB) transplant for refractory, relapsed T-cell ALL. Conditioning consisted of TBI, melphalan, and anti-thymocyte globulin (ATG ), with cyclosporin A (CsA) and solumedrol for GVHD prophylaxis. She engraf ted and a day 34 bone marrow aspirate showed 100% donor cells and no eviden ce of leukemia. The post-transplant course was complicated by mild grade I acute GVHD involving skin, and limited chronic GVHD of the gut which resolv ed with the addition of 1 mg/kg/day of steroids to her CsA prophylaxis. One hundred and ninety days after transplantation the patient developed pancyt openia and was subsequently found to have a leukemic relapse. Immunosuppres sion was discontinued and she was started on G-CSF. and erythropoietin. Mod erate skin and gut GVHD developed which was treated with both topical and l ow-dose oral steroids. Over the next few weeks she became transfusion indep endent and a follow-up bone marrow aspirate showed complete remission. She continued in complete remission for 4 months, at which time localized leuke mic relapse was found in a soft tissue breast mass in spite of continued bo ne marrow remission. While the patient ultimately died of progressive disea se, this case demonstrates that mismatched UCB in conjunction with G-CSF is capable of generating a GVL effect that can induce a complete remission.