To the Editor: Relapse is still a problem for leukemias, particularly in the autologous bone marrow transplantation (ABMT) setting. Moreover, the CD20 positive phenotype, de®ned as >20% expression, may be associated with a worse outcome [1]. Therefore, our experience with such a patient in whom we administered Rituximab (anti-CD20 monoclonal antibody, Mabthera 1 ) post-ABMT is of interest.
She was a 13 1/2-year-old adopted girl from Peru who had acute B-precursor acute lymphocytic leukemia (ALL), and was treated according to the high-risk Pediatric Oncology Group protocol 9406. Autologous bone marrow was collected 6 months after the initial diagnosis. She had Central Nervous System (CNS) and bone marrow relapse 1 year after the end of treatment. Immunophenotyping showed presence of blasts with the surface markers CD34/CD19 77%, CD20 22%, CD10 76% as in initial diagnosis sample. Chemotherapy was started. No hematopoietic stem cell donor or compatible cord blood was found. Following conditioning with 12 Gy of total body irradiation and etoposide (60 mg/kg), autologous bone marrow (1 Â 10 8 nucleated cells/kg) was given. Rituximab was administered at 375 mg/m 2 once a week for a total of four doses starting from D 35 post-BMT before bone marrow recovery. At D 83, IL-2 was started at 18 Â 10 6 IU/m 2 /24 hr continuous infusion per dose 3 doses/week for a period of 3 months. However, even the ®rst dose had to be reduced to 13 Â 10 6 IU/m 2 because of fever (39±40 C) and oliguria. The subsequent doses had to be decreased due to high fever, headaches, severe mucositis, vomiting, abdominal cramps, and oliguria. The patient was dependent on erythrocyte and platelet transfusions for 7 months post-transplantation. She is at present in CR 2 at 2 years post-ABMT.