Autologous Peripheral Blood Stem Cell Transplantation (PBSCT) Combined with Haploidentical Lymphocytes Infusion Increases the Long Term Survival of Adult Acute Myeloid Leukemia with Standard Risk.

OBJECTIVES: The long term survival of adult patients with acute myeloid leukemia with standard risk factor which treated by autologous peripheral blood stem cell transplantation is about 30–50%. We designed a new therapy to improve the long term survival of adult patients with acute myeloid leukemia with standard risk factor. After completely remission, patients underwent 2–3 courses of consolidation chemotherapy. Autologous peripheral blood stem cell transplantation (PBSCT) was performed. After hematology recovery, haploidentical lymphocytes irradiated with 7.5 Gy were infused into patients. Here we evaluate the outcome of this approach in adult patients with acute myeloid leukemia with standard risk.

METHODS: From July 1998 to July 2007, twenty-four patients including 17 males and 7 females, median age 36 year old (range 14–58) with acute myeloid leukemia with morphology M2 subtype and normal karotype received this approach therapy. Autologous peripheral blood stem cells were collected by aphereses and froze in −198° and storied after 2–3 courses of median dose cytarabine consolidation chemotherapy The autologous stem cells were grafted to patients following the conditioning with the BuCy regimen (Bu16mg/kg and CTX 120mg/kg). Haploidentical lymphocytes obtained by leukapheresis from sibling donors or other relatives were irradiated with 7.5 Gy and were infused into patients after hematopoietic reconstitution.

RESULTS: A median dose of 2.5×10⁸/kg, nucleated cells/kg (range, 2.97×10⁷/kg-6.0×10⁸/kg)containing 5 × 10⁶ CD34+ cells/kg (range,1.5– 4.8) were autografted. All patients were got hematopoietic reconstitution. The median time for granulocyte recovery >0.5 × 10⁹ /L was 11 days and for platelets >20 × 10⁹/L was 14 days following transplantation. All patients were administrated a median dose of 2.0×10⁸/kg haploidentical lymphocytes irradiated with 7.5 Gy. Severe acute GVHD occurred in two patients. One died with severe acute GVHD. Hematopoietic reconstitution delayed in four patients. No other side effects were observed. For the whole group of 24 patients, the median overall survival rate (OSR) was 83.7%. The median disease-free survival (DFS) time was 28.3 moths (range 2–120 m) and the 5-year DFS rate was 50%. The 2-year OS rate was 71%. After a median follow-up of 5.0 years from transplantation, the median DFS and OS were 28.3 years respectively, and the 3-year rates were 50%. Nineteen patients were still in continuous complete remission, 4 patients had relapsed and 3 had died.

CONCLUSIONS: Autologous peripheral blood stem cell transplantation (PBSCT) combined with haploidentical lymphocytes infusion may prolong the long term survival of adult acute myeloid leukemia with standard risk.