[A clinical study of haploidentical and G-CSF primed bone marrow transplantation by using CD25 for aGVHD prophylaxis]

To explore the feasibility of using CD25 monoclonal antibody (Basiliximab) in T-cell undepleted allo-BMT with graft from haplotype-matched related donor for acute GVHD prophylaxis. Twenty-eight patients with leukemia received allo-BMT from HLA two or three loci mismatched related donors. The donors were given G-CSF (Lenograstim) 250 micro g/d for 7 doses prior to marrow harvest. CSA, MTX, ATG and mycophenolate mofetil (MMF) were combined for GVHD prophylaxis. ATG 5 mg/(kg.d) was infused from day 4 to day 1 before transplantation and MMF was administered from day 7. In the study group, the patients received additional CD25 monoclonal antibody for aGVHD prophylaxis. CD25 20 mg each by 30 min intravenous infusion on 2 hours before transplantation and day 4 after transplantation was administered while no application of CD25 in the controls. The outcomes of transplantation were compared between the stud y and control groups. The results showed that the median number of CD34(+) cell in graft was 5.9 x 10(6)/kg in the control group and 7.9 x 10(6)/kg in the study group. The median number of CD3(+) cell was 48 x 10(6)/kg and 52 x 10(6)/kg respectively (P > 0.05). All patients showed 100% donor-typed hematopoietic cells after transplantation by cytogenetic evidence. Five out of fifteen patients in the control group experienced II - IV acute GVHD. While none of thirteen in the study group developed the II - IV acute GVHD. However, none in both groups developed extensive cGVHD. The median follow-up duration was 8 (3-15) months in the study group and 26 (15-36) months in control. In the study group, one patient died from transplant related mortality (CMV infection); no one relapsed; and 12/13 patients survived in disease-free situation within the period of follow-up. In the control group, six patients died from transplant related mortality (3 GVHD, 2 infection and 1 relapsed) and 9/15 patients survived in disease-free situation. The one-year probabilities of disease-free survival (DFS) in two groups were significantly different (P < 0.05). It is concluded that the transplant from haploidentical donors used CD25 antibody is effective and feasible in preventing acute severe GVHD and improving DFS. The major histocompatibility barrier in the haploidentical related allo-BMT could be crossed by donors primed with G-CSF and GVHD prophylaxis with CD25 antibody in the hosts.