Quantitative evaluation of BCR-ABL amount of transcript post mobilization with G-CSF of peripheral blood stem cells from chronic myeloid leukemia patients in cytogenetic response.
ABSTRACT We studied nine patients affected by chronic myeloid leukemia (CML Ph+ and bcr-abl positive) and treated with alpha-interferon (alpha-INF) in order to: first, to evaluate the feasibility of a mobilization of peripheral blood stem cells induced by granulocyte-colony-stimulating factor (G-CSF) and the contamination by Ph+ cells and second, to quantify the amount of bcr-abl leukemia associated transcript by a quantitative assay during mobilization procedures, and post mobilization follow-up. Eight achieved a complete karyotypic remission before mobilization obtained with discontinuation of alpha-INF for few days and G-CSF at a dosage of 15 microg/kg/day for 5-7 consecutive days. By quantitative-competitive polymerase chain reaction (QC-PCR) assay, all the leukaphereses and bone marrow samples during post mobilization follow up were studied to determine the amount of bcr-abl transcript. Karyotypic and molecular analysis on evaluable leukapheresis showed that all the harvests were Ph negative and bcr-abl positive: in seven cases the levels of bcr-abl transcript were higher or equal to the pre-apheresis status. In three out of four patients, who underwent more than one leukapheresis procedure, we noticed a decreasing amount of bcr-abl contamination from the first to the last apheresis. Our results suggest that in patients who achieved a complete or major cytogenetic conversion with alpha-INF, it is possible to obtain a sufficient amount of PBSC for autografting by leukapheresis following priming G-CSF therapy and that the amount of neoplastic transcript does not seem to increase.
Article: Successful autologous stem cell collection in patients with chronic myeloid leukemia in complete cytogenetic response, with quantitative measurement of BCR-ABL expression in blood, marrow, and apheresis products.[show abstract] [hide abstract]
ABSTRACT: Imatinib mesylate is the initial therapy of choice for chronic myeloid leukemia in chronic phase (CML-CP), but in some patients, the disease becomes resistant to imatinib. Autologous stem cell transplantation using cells collected while in complete cytogenetic response (CCyR) may represent a therapeutic option for these patients. We mobilized and collected autologous CD34(+) stem cells from 20 CML-CP patients in CCyR, 19 of whom were taking imatinib, and measured BCR-ABL expression in the apheresis products, blood and bone marrow using real-time quantitative PCR (RQ-PCR). Stem cells were mobilized with G-CSF 10 microg/kg daily for 5 days. In patients whose initial collection was <2x10(6) CD34(+) cells/kg, G-CSF dose was increased to 10 microg/kg twice daily on the second attempt, and imatinib was held for 14 days if a third attempt was necessary. All 20 patients successfully mobilized the target yield of 2 to 5x10(6) CD34(+) cells/kg; 16 reached target yield with the first mobilization. The median number of CD34(+) cells collected was 4.4 (range, 2.0 - 8.4)x10(6)/kg in a median of 3 (range, 2 - 6) apheresis days. Of 17 patients whose stem cell products were evaluable by RQ-PCR, 11 (65%) had >or=1 daily product with undetectable BCR-ABL; 4 of these (24%) had no detectable BCR-ABL in any apheresis products. BCR-ABL expression in apheresis products was correlated with levels of expression in the blood and marrow prior to mobilization. No patient has yet required transplantation. With median follow-up of 18 months, all patients remain in CCyR and 9 of 16 (54%) have undetectable BCR-ABL in the most recent blood and marrow sample.Leukemia & lymphoma 04/2008; 49(3):531-7. · 2.40 Impact Factor