Background & objective: The complete remission of refractory leukemia treated with conventional chemotherapy is below 50 percent. The high dose chemotherapy can cause more mortality of patients with refractory leukemia. Cytolysis of leukemia cells induced by halpotype lymphocytes was observed in vitro in our previous experiment. In order to improve the complete remission of refractory leukemia and decrease the complication of chemotherapy,the authors treated the patients with refractory leukemia by combined chemotherapy and halpotype lymphocytes infusion and to assess the therapeutic effects and the side effects of this modality.
Methods: Sixteen patients with refractory leukemia were treated by combined chemotherapy. Halpotype lymphocytes irradiated by 7.5 Gygamma radial were infused when patient's white cells count was at the lowest after the chemotherapy. A mean number of 1x10(8)/kg (range:0.8-1.2x10(8)/kg) of halpotype lymphocytes irradiated by 7.5 Gygamma radial was infused. The side effects of infusion of halpotype lymphocyte and completed remission rate were observed.
Results: Out of thirteen patients with refractory acute non-lymphocyte leukemia, eleven cases got complete remission and two partial remissions. Out of three patients with refractory acute lymphocyte leukemia, two got complete remission and one no reaction. The total remission rate was 81.2%. No severe side effects and no transfusion related graft versus host disease was observed.
Conclusion: The results show that chemotherapy combined with 7.5 Gy irradiated halpotype lymphocyte infusion could improve the complete remission of refractory leukemia and decrease the complications caused by chemotherapy.