Abstract: Objective: To Evaluate the purging effect of interleukin-2 （IL-2） and interferon γ （IFN-γ） on minimal residual leukemic cells during autologous bone marrow transplantation and the use of RT PCR technique in determining the purging effect. Methods: The imitative chronic myeloid leukemic bone marrow in remission had been cultured in liquid mediam with IL-2 and IFN-γ for 1-6 days, and the puring effect was determined by detection of the bcr/ab1 mRNA. Results: The bcr/ab1 mRNA could be detected by RT PCR among bone marrow treated with IL-2 or IFN-γ alone for 24, 48 and 72 hours, but it was negative after 6 days of culture. And among bone marrows treated with both IL-2 and IFN-γ, the bcr/ab1 mRNA was positive when treated for 24 and 48 hours and negative when treated for 72 hours and 6 days. In those contrast bone marrows ,which neither IL-2 nor IFN-γ was used, the bcr/ab1 mRNA could still be detected after 6 days of culture. Conclusion: IL-2 and IFN-γ can be used to purge K₅₆₂ leukemic cells in bone marrow in remission and they have coordinate effect when used together. RT PCR is a sensitive and reliable method to evaluate the purging efftec.