Abstract: Thirty patients （15 males and 15 females, with a median age of 35 years） with chronic myeloid leukemia （CML） in first chronic phase received allogeneic bone marrow transplantation from July 1983 to March 1989. All patients were ph' chromosome positive. They received bone marrow from HLA-identical siblings with negative mixed lymphoid cell culture.
The conditioning regimen consisted of TBI （10.2-12 Gy in 6 fractions given in 2 days with a dose rate 0.125-0.204 Gy/min） and CTX （60 mg/Kg body weight each day for 2 successive days）. In an attempt to prevent GVHD, bone marrow depleted of T cell with Campath-1 monoclonal T-cell antibodies plus cyclosporine A were transplanted to 20 patients. For comparison, the remaining 10 patients received marrow without T cell depletion in combination with cyclosporin A and MTX （day+ 1, 3. 6 and 11）.
The results indicsted that T cell depletion was associated with both beneficial and adverse consequences. The incidence of acute （≥grade 2） and Chronic GVHD was siginilicantly decreased by T-cell depletion （P＜0.05 and ＜0.005, respectively）, but ph' chromosome positive cells reappeared more frequently and duration of complete remission was short （P＜0.02 and ＜0.05, respectively）. Infections, GVHD and interstitial pneumonitis continued to be the principal causes of death following BMT in patients with leukemia.