Two patients undergoing marrow transplantation for acute lymphocytic leukaemia in third remission received from histocompatible siblings marrow pretreated with a mixture of three anti-T-cell immunotoxins, consisting of murine monoclonal antibodies covalently linked to ricin. This marrow processing effectively- eliminated functional T-cell responses while preserving the marrow precursors necessary for sustained haematoimmunopoietic engraftment. No post-transplant immunoprophylaxis was administered. Both patients showed prompt peripheral engraftment and were discharged from hospital within a month of transplantation. No toxic effects or graft-versus-host disease were apparent after the administration of immunotoxin-treated marrow. Ex-vivo immunotoxin pretreatment appears a safe and simple procedure which deserves further clinical testing as a sole method of graft-versus-host disease prophylaxis.
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enough to treat many patients, eliminating the variability experienced with other biological reagents such as sheep erythrocytes and rabbit complement. We thank Christie Soderling, Karen Jordan-Heinitz, Ellen Sevenich, and Susan Azemove for technical assistance; Carol Krawczak for preparing the manuscript; and Dr J. Faegler, Omaha, Nebraska, and Dr R. Weetman, Indianapolis, Indiana, for referring the patients. This work was supported by NIH grants ROI-CA21737 and RO1-CA31618. A. H. F. is recipient of Clinical Investigator Award NIADD 5K08-AM 00959.