Jim Houston @ St. Judes had a similar posting. My lab processes+cryopreserves bone marrow and apheresis collections for use in transplantation. We also perform CD34 and lymph subset analysis in the lab. Sorting of hematopoietic progenitors for use in transplant is very intriguing. A growing body of evidence has shown that tumor cells can contaminate the cell collections and contribute to disease relapse post-transplant. Purifying CD34+ cells could help improve disease-free survival in breast cancer, lymphomas, and various solid tumors. Probably not useful for most leukemias since the tumor cells may express the CD34 antigen. I know of no published papers on the subject of flow sorting of CD34+ cells for transplant. Problem is cell numbers. An average peripheral blood apheresis has 4x10e10 nucleated cells. CD34% of the product is around 1-5%. Sorting of the apheresis collection at 10,000 cells/sec will take over 3 weeks to complete. I've heard some claims that some special sorters can operate efficiently at 100,000 cells/sec. Still 3 days. Bone marrow harvests have 1 log less cells but many centers are getting away from using the cells since the collection procedure is more difficult on the patient and clinical staff. A number of biotech companies have developed immunological separation methods such as immunoabsorption (Cellpro) and immunomagnetic (Baxter). These procedures take about 3-4 hours, can achieve 90-99% purities and around 50-60% yields. I've heard of plans from some biotech companies interested in gene therapy to enrich the CD34+ cells from PB or BM using one of these immunomethodologies. Then use a cell sorter on the selected product to sort out the pluripotent hematopoietic stem cells (CD34+,CD38-,CD90+). Whole process can probably be done in a day. To get the flourescent antibodies off of the cell surface, culture overnight at 37°C. Tim Farley Hematopoietic Stem Cell Lab NY Blood Center tfarley@computer.net ---------- > From: Lucia Mariano da Rocha Silla <silla@conex.com.br> > To: Cytometry Mailing List <cytometry@flowcyt.cyto.purdue.edu> > Subject: CD34 cells separation > Date: Monday, July 28, 1997 6:26 PM > > > Dear all! > Is there anyone with informations about CD34s separation by flow for > transplantation? I am very much interested in learn how to do that. Thak you > very much. > > Lucia Silla > Laboratório de Hematologia Celular > Faculdade de Medicina > Pontificia Universidade Catolica > Porto Alegre - RS. BRAZIL >
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