A SINGLE COURSE OF REMISSION REINDUCTION CHEMOTHERAPY FOR ACUTE MYELOGENOUS LEUKEMIA RELAPSING AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATIONIS COMPLICATED BY GRAFT-VERSUS-HOST DISEASE AND FOLLOWED BY SUSTAINEDCOMPLETE REMISSION

Graft-versus-host disease (GVHD) remains a major immunological complic ation after allogeneic bone marrow transplantation (allo-BMT), but als o favors development of the beneficial graft-versus-leukemia (GVL) eff ect. A patient with AML-M4 (inv (16)) is described, who was given non- myeloablative remission reinduction therapy for leukemic relapse (inv (16), trisomy 8) diagnosed on day 184 after HLA-compatible sibling BMT . On day 236, ie about 6 weeks after completion of this course, a clin ical syndrome suggestive of acute GVHD grade 3 had developed. Skin bio psy confirmed the clinical diagnosis of GVHD, with a compatible liver biopsy. Transfusion-associated GVHD was ruled out by analysis of short tandem repeat (STR) alleles in the skin biopsy, revealing alleles fro m donor and recipient but not from third party origin. Cyclosporin A ( CsA) therapy, which had been tapered between days 150 and 175, was res umed, resulting in a favorable response and gradual transition to limi ted chronic GVHD. The patient has since remained in complete remission with an excellent performance status for more than 40 months, without further chemotherapy. Thus this biopsy proven case of GVHD was induce d by marrow donor lymphocytes more than 200 days after transplantation and apparently triggered by remission reinduction chemotherapy. The c ase indicates that intensive non-myeloablative chemotherapy can cure A ML relapsing after allo-BMT. The therapeutic effect in this case proba bly involved a direct pharmacological suppression of the leukemic clon e followed by a GVL effect initiated by donor-derived alloreactive T l ymphocytes.