Immunomagnetic selection of CD34⁺peripheral blood stem cells for autografting in patients with breast cancer

Abstract

Summary. Contamination of transplants with tumour cells may contribute to relapse after peripheral blood stem cell transplantation (PBSCT). We studied the feasibility of CD34 þ cell selection from blood-derived autografts obtained following G-CSF-supported cytotoxic chemotherapy in a group of 25 patients with breast cancer (10 with high-risk stage II/III and 15 with stage IV without bone or bone marrow involvement).Using immunomagnetic beads (Isolex 300 SA, Baxter) CD34 þ cells were enriched and released by chymopapain resulting in a median purity of 95% (range 82-99%) and a median recovery of 80% (range 27-132%). The enrichment procedure did not change the proportion of CD34 þ subsets coexpressing HLA-DR, CD38 and Thy-1, while L-selectin was removed from the cell surface following selection. Using a sensitive immunocytological technique with a cocktail of epithelial-specific antibodies (anti-cytokeratin 8, 18 and 19; HEA125; BM7 and BM8), five leukaphereses products contained epithelial cells, whereas the selected CD34 þ cell fraction was free of tumour cells. A neutrophil count of 0·5 × 10 9 /l and a platelet count of 20 × 10 9 /l was reached after a median time of 14 and 10 d following 40 high-dose chemotherapy (HDC) cycles. Our results indicate that immunomagnetic selection of CD34 þ cells yields highly purified autografts devoid of tumour cells whereas the engraftment ability of the progenitor and stem cells is fully retained.

Selective loss of progenitor subsets following clinical CD34+ cell enrichment by magnetic field, magnetic beads or chromatography separation

“…[10][11][12] Preclinical studies have suggested several clinical applications of highly purified CD34 ϩ cells, including tumour cell purging. Enrichment of CD34 ϩ cells has been proven to deplete tumour cells from autografts, [13][14][15][16][17][18] and is necessary for ex vivo expansion of progenitor cells. Furthermore, highly purified CD34 ϩ cells are essential for optimal cytokine-mediated expansion and differentiation in short-term culture.…”

Enrichment of peripheral blood CD34+ cells for transplantation using a fully automated immunomagnetic cell selection system and a novel octapeptide releasing agent

“…Chymopapain has been shown to modify the CD34 + cell surface. 5,36 In contrast, peptide release has been found by scanning electron microscopy to result in a highly homogeneous cell population with complete surface integrity and free of magnetic beads. 18 Murine MoAbs recognize different epitopes of the CD34 sialoglycoprotein.…”

“…[1][2][3][4][5] Among the potential benefits of CD34 + cell enrichment for patients with malignant disease is the concomitant depletion of tumor cells in autologous transplant grafts. [5][6][7][8] CD34 antigen has been shown to be present primarily on progenitor and stem cells, and is not found on mature blood cells or non-Hodgkin's lymphoma, myeloma or most solid tumor cells. 9 In allogeneic transplantation, CD34 selection can provide hematopoietic cells that support hematological recovery and can serve to reduce the number of T cells in transplant grafts.…”

Toward complete laser ablation of melanoma contaminant cells in a co‐culture outgrowth model via image cytometry

“…With the 103 objective, tight square packing of the smaller HSC cells with low (0.1%) proportion of contaminant cells, and fast, dynamic ablation implemented in parallel with scanning, the 175 million cells required for one adult patient (21,22) would be processed in as little as 1 h, or as fast as about 48,600 cells/s. At lower magnification, Cyntellect (San Diego, CA) has reported microscope image-based ablation at a rate of 100,000 cells/s with as many as 2,000 cells/s (or 2%) contaminant cells (4).…”