[Bone marrow transplantation in chronic myeloid leukemia]

Chronic Myelogenous Leukemia (CML) is an oncohematological disease characterized by a clonal proliferation concerning the primitive hematopoietic cell. A typical cytogenetic alteration known as Philadelphia Chromosome (Ph1), a 9:22 chromosomic translocation which produces a hybrid gene BCR/ABL, is present in 95% of the patients. Nineteen CML patients (9 female and 10 male) underwent Bone Marrow Transplantation (BMT). Median age was 32 years (range 9 to 47); 15 of them were in chronic phase (CP), and 4 in accelerated phase (AP). At diagnosis, all patients were Ph1+, BCR/ABL+. The conditioning regimen consisted of busulphan and cyclophosphamide while patients in AP received etoposide as well. Seventeen patients received cyclosporine A, methotrexate and methylprednisone as prophylaxis for Graft Versus Host Disease (GVHD) while 2 patients received only the first two drugs. The 9.22 translocation was determined by means of RT-PCT technique using the primers NB1+, Abl3, B2A, CA3 and A2. The sensitivity of the method was 1 x 10(-6). Among the 19 patients who entered the protocol, 14 are alive and in clinical, hematological and cytogenetic remission (Ph1-) and 3 patients died due to acute GVHD, 1 due to graft failure and 1 due to Hemolytic Uremic Syndrome. Of the 4 transplanted patients in AP, 3 are alive and in complete remission. The patients had a 74% survival, with a median follow-up of 655 days. Complete hematopoietic chimerism was demonstrated in 16 patients, with the study of 3 loci, D1S80, APO B and D17S30. No relationship was found between post BMT hybrid BCR/ABL (RT.PCR) persistence and disease relapse; the presence of acute and/or chronic GVHD did not influence the BCR/ABL positivity. In our experience, BMT has proved to be the only therapeutic alternative for CML with complete clinical, hematological and cytogenetic remission and a mean survival of 74%, comparable to the international experience.