Objective: To assess the effectiveness of transplantation and observe the kinetics of residual leukemic cells during early post-transplantation period in chronic granulocytic leukemia (CGL).
Methods: Ten normal controls, seven untreated CGL patients and eleven CGL patients after allogeneic bone marrow transplantation (allo-BMT) or peripheral blood stem cell transplantation (PBSCT) were studied by interphase fluorescence in situ hybridization (I-FISH) with the FITC fluorescein labeled BCR probe. Conventional cytogenetic analysis (CCA) and reverse transcriptase-polymerase chain reaction (RT-PCR) were also employed.
Results: The normal cutoff was defined as less than 6.68% (x +/- 3s) from the analysis of normal controls. The reproduciblity of FISH method was confirmed by serial dilutions by mixing Ph positive cells and normal cells. Forty specimens from 11 CGL patients at 1 week to 6 years post-BMT were investigated after PBSCT and the results showed that (1) FISH and RT-PCR could accurately evaluate Ph (+) cells during early transplantation period (within one month), but RT-PCR was more sensitive in six months after BMT. (2) Residual Ph (+) cells tended to be linear decreasing with the time after transplantation and fell in normal range in most samples three months later. The mean time of normaligation was 57 days (20 to 170 days). (3) One case relapsed and received a second transplantation. FISH presented more precise data for predicting relapse as compared to CCA and RT-PCR.
Conclusions: I-FISH as a useful tool can not only offer more precise assessment of residual leukemic cells compared with CCA and RT-PCR, but also provide dynamic monitoring during early post-BMT period to evaluate the transplantation outcome and predict relapse.