CD34+ cell is an important surface marker of the hematopoietic stem/progenitor cells. "Positive selection" method in which this marker is adapted has been used to obtain highly purified CD34+ cells that play an important role in the study of the hematopoietic stem/progenitor cells. The transplantation of the bone marrow and peripheral blood stem cells that now generally applied is actually the transplantation of the mixture including the stem/progenitor cells and the mature cells of various lineages. The hematopoietic reconstitution needs only enough number of stem/progenitor cells and other fractions would even be harmful to transplantation. "Negative selection" method has been used to remove the non-stem/progenitor cells, but its effectiveness was usually not good and it could be harmful to the stem/progenitor cells. "Positive selection" method not only gets rid of the above flaw but also can be used to obtain high dose of purified CD34+ cells to meet clinical need for the stem/progenitor cells. The transplantation of CD34+ cells purified with clinical-grade Magnetic Activated Cell Sorting system, CliniMACS(Miltenyi Biotec /AmCell), has been proceeded in Europe and the preliminary study was successful (1). Since 1998, using CliniMACS system, we have purified CD34+ cells from 27 leukapheresis products which were separated with CS-3000 plus blood cell separator from 24 mobilized patients or normal donors. 21 patients have received transplants, of which 18 patients are eligible for preliminary evaluation.
3. Patients and methods
a) Donors and recipients
24 donors, including 15 males and 9 females ，the median age was 37 (range:12-55)，normal donor (ND) 5 cases，multiple myeloma(MM)6 cases，non-Hodgkin's lymphoma(NHL)3 cases， metastatic breast cancer(BC)2 cases，Hodgkin's disease(HD)1 case and medulloblastoma (MB) with bone marrow infiltration 1 case，auto-immune diseases 5 cases，Table 1 shows the details. Purified CD34+ cells have been successfully reinfused to 16 patients with autologous cells and 5 patients with HLA haploidentical cells. Table 2 shows the details.
b) PBSPC mobilization and harvest
43 leukapheresis products were collected using Baxter CS-3000 plus blood cell separator with 10L of circulatory volume after the donors mobilized with chemotherapy plus G-CSF or only with G-CSF (some of those plus GM-CSF). The purification of CD34+ cells were proceeded from 11 leukapheresis products within the same day of collection, while 16 leukapheresis products were stored at 4℃ until the next day and were mixed with the leukapheresis collected in the next day, the purification of CD34+ cells were proceeded from the mixed leukapheresis products.
1.3 Purification of CD34+ cells with CliniMACS
(陈虎)
|
