Anti-CD25 instead of ATG for the Conditioning of HLA-Mismtched Hematopoietic Stem Cell Transplantation.

To analysis the effect of Anti-CD25 instead of ATG for the conditioning of HLA-mismatched hematopoietic stem cell transplantation (HSCT).

21 cases underwent HLA-mismatched HSCT in our hospital from Mar. 2006 to May 2009. Diagnosis included ANLL(n=9)(2 in CR,7 in Relapse)?ALL(n=2), AHL(n=2), CML(n=4), MDS (n=2) and SAA (n=1), HLA Typing : All patients receive transplants from HLA-mismatched related donors. Among whom, 1,2 and 3 antigen mismatched were 11,8 and 2 cases respectively. Conditioning regimen consisted of modified BU/CY (n=12), BU/CY (n=6), FLU/BU (n=2) and CY/ATG for SAA(n=1). In addition, ATG(Thymoglobuline, 5-7.5mg/Kg, iv, divided into three days, -8∼-6d) was given for 8 patients. Anti-CD25 was given for 13 patients, including Daclizumab (50mg/d, -1?,03?,+4?,+11d) for 7 patients and Basiliximab (20mg/d, -1?,02?,+2?,+7d) for 6 patients. GVHD prophylaxis consisted of CSA and short course of MTX. In addition, MMF was given in all patients at the dosage 1.0 g/d for one month. The donors were given granulocyte colony-stimulating factor (G-CSF) at a dosage of 5 μg/Kg.d subcutaneously for 5 days, bone marrow was collected on day 3, peripheral blood stem cells were collected at day 4 and 5.

Engraftment was obtained in all 21 patients, the median time to WBC >0.5×10⁹/L and BPC>20×10⁹/L in ATG and Anti-CD25 group were 14, 13d and 13, 12d, respectively (p>0.05), I∼II aGVHD accurred in 3 cases(37.5%) in ATG group and 5 cases(23.1%) in Anti-CD25 group,III∼IV aGVHD was observed in 1 case (12.5%) in ATG group and 2 cases (15.3%) in Anti-CD25 group. cGVHD was evaluable in 14 patients who survived after day +100, Extensive cGVHD developed in 1 (20%) of 5 patients in ATG group, and in 4 (44%) of 9 patients in Anti-CD25 group. Daclizumab and Basiliximab were not cause any infusion-related toxicity. Up to now, 13 patients survived in complete remission follow up 3-59 months, 4 cases (50%) died (3 in TRM and 1 in relapse) in ATG group, 4 cases (30.7%) died (1 in TRM and 3 in relapse) in Anti-CD25 group.

The replacement of ATG with Anti-CD25 seems to be more safety and effective for the conditioning of HLA –mismatched HSCT.

No relevant conflicts of interest to declare.