摘要Background Relapse remains an obstacle to successful allogeneic haematopoietic stem cell transplantation (alIo-HSCT) for patients with acute leukaemia and no standard treatment is available. We assessed fludarabine and cytarabine with transfusion of donor haematopoietic stem cell in treating the relapse of acute leukaemia after alIo-HSCT.Methods Seven patients, median age 34 years, with relapse of acute leukaemia after alIo-HSCT received combination chemotherapy of fludarabine with cytarabine for 5 days. Five patients suffered from acute myeloid leukaemia (2 refractory) and 2 refractory acute lymphoblastic leukaemia. After the transplantation, the median relapse time was 110 days (range,38-185 days). Two days after chemotherapy, 5 patients received infusion of donor's peripheral blood stem cells, mobilized by granulocyte colony stimulating factor. No prophylactic agents of graft versus host diseases were administered.Results Six patients achieved haematopoietic reconstitution. DNA sequence analysis at day 30 after treatment identified all as full donor chimera type. The median observation time was 189 days. After the treatment, the median time for neutrophilic granulocyte value ≥0.5x109/L and for platelet value >20x109/L were 13 days (range, 10-18 days) and 15 days (range, 11-24 days), respectively. Graft versus host disease occurred in 2 patients (acute) and 3 (chronic). Five patients suffered from pulmonary fungal infection (2 died), 3 haemorrhagic cystitis and 2 cytomegalovirus viraemia. The other patients died of leukaemia related deaths. Three patients with chronic graft versus host disease who had received donor peripheral blood stem cells reinfusion have survived for 375 days, 232 days and 195 days, respectively.Conclusions Fludarabine with cytarabine plus the donor haematopoietic stem cell should be considered as an effective therapeutic regimen for relapse of acute leukaemia after alIo-HSCT. The disease free state of patients may increase, thou.gh with hi qh risk of secondary fungal infection.