Active T cell depletion in graft engineering

  • Depletion of potentially harmful cells from grafts
  • Maintenance of effector cells and engraftment-facilitating cells
  • Innovative depletion strategies on the CliniMACS® Platform

Active T cell depletion allows a focused depletion of unwanted cells, while several populations of potentially therapeutic beneficial cells are preserved within the graft. Different strategies can be applied, as described below.

CD3/CD19 depletion

In contrast to the strategy of CD34+ cell enrichment, active T and B cell depletion results in a graft that contains CD34+ stem cells, CD34stem cells, other progenitor cells and natural killer (NK) cells, monocytes, and dendritic cells, which might have engraftment facilitating effects1. This active T cell depletion strategy is currently being evaluated, especially in combination with reduced intensity conditioning2,3.

TCRα/β depletion

Another possibility for active T cell depletion is provided by the CliniMACS® TCRα/β System. 
Cells which are responsible for the development of graft-versus-host disease (GvHD) are thought to derive from the pool of TCRα/β+ T cells, whereas TCRγ/δ+ T cells and NK cells may bear graft-versus-leukemia (GvL) effects, engraftment facilitating functions, and may help to fight infections4-7.
Thus, depletion of TCRα/β+ T cells may be a helpful tool to prevent GvHD, while preserving different cell populations of potential therapeutic value within the cellular product8. The CliniMACS TCRα/β product line can also be used in combination with the CliniMACS CD19 Reagent to additionally remove the CD19+ B cells from the graft9.

Video
Automated TCRα/β+ T cell depletion in stem cell transplants with the CliniMACS® TCRα/β System

Learn how TCRα/β and CD19 depletion is facilitated with the help of the CliniMACS Instruments.

CD45RA depletion

CD45RA is expressed on naive T cells, whereas memory T cells are CD45RA–. CD45RA depletion results in a cellular product passively enriched for memory T cells, while naive T cells, which have the potential to induce GvHD, are depleted10. The potential benefit of memory T cell infusion probably results from the high anti-infection potential of this cell type. It should be noted that CD45RA is also present on part of other lymphocytes and hematopoietic stem cells. This should be considered if memory T cell infusion is planned to be combined with the initial transplant. In exceptional cases it may happen that donors have CD45+ memory T cells. This should be tested prior to any clinical application.

Video
Automated magnetic depletion of CD45RA+ naive T cells with the CliniMACS® CD45RA Reagents

Learn how CD45RA depletion is facilitated with the help of the CliniMACS Instruments.

Please find below a list of product lines that can be used for active T cell depletion.

CliniMACS® CD3/CD19 Product Line – For simultaneous T and B cell depletion.

CliniMACS TCRα/β Product Line – For TCRα/β+ T cell depletion. Aim: Maintenance of γ/δ T cells, NK cells, and graft facilitating cells in the graft. For additional removal of B cells, this product line can also be used in combination with CliniMACS CD19 Product Line.TCRα/β depletion is currently available as RUO (research use only) in the USA.

CliniMACS CD45RA Product Line For naive T cell depletion. Aim: Maintenance of memory T cells in the graft or DLI product. Part of CD34 hematopoietic stem cells are also CD45RA+. This should be considered if memory  cell infusion is planned to be combined with the initial transplant. In exceptional cases it may happen that donors have CD45+ memory T cells. This should be tested prior to any clinical application.

Allogeneic stem cell transplantation is a therapeutic option for the treatment of patients with distinct malignant and non-malignant diseases.1,11

Active T cell depletion strategies can be used for haploidentical transplantation when an human leukocyte antigen (HLA) Id Sib or other HLA-matched related or unrelated donor is not available. CliniMACS technology enables the active depletion of B cells, T cells, or T cell subsets from the graft (CD3/CD19 depletion, TCRα/β/CD19 depletion). These depleted grafts have been used in the context of reduced intensity conditioning (RIC) regimens12-14.

CD3/CD19 depletion
Clinical investigation during recent years has focused on treatment of hematological malignancies but, to a certain extent, solid tumor disease and non-malignant disease have also been the subject of clinical studies15,16. Data have been acquired for patient populations, both children and adults, which demonstrate improved engraftment and immune reconstitution13,17-19. The authors conclude that CD3/CD19 depletion for graft engineering under RIC is a promising approach for patients without a matched related donor.

Especially children and elderly patients potentially benefit from the strategy of RIC. Recent findings show that a CD3/CD19 depletion graft engineering strategy for non-HLA identical donor stem cell transplantation in children resulted in a remarkable cumulative TRM rate of only 10.7% - a result which was previously only found in HLA Id Sib transplantation20.
 

TCRα/β/CD19 depletion
Results are accumulating on a most innovative active T cell depletion strategy, which is based on TCRα/β/CD19 depletion of HLA-mismatched stem cell grafts for treatment of children with advanced malignant and non-malignant disease under RIC14,21. Patients showed a rapid and sustained engraftment, a rapid immune reconstitution, and a low incidence of graft-versus-host disease (GvHD). More recent data show that promising data could be generated not only on the basis of RIC but also after myeloablative conditioning, even when no post-transplant GvHD prophylaxis was administered9.

  1. Handgretinger, R. et al. (2007) Feasibility and outcome of reduced-intensity conditioning in haploidentical transplantation. Ann. N. Y. Acad. Sci. 1106: 279–289.
  2. Lang, P. et al. (2006) Bone Marrow Transplant. 37 (Suppl. 1): 67.
  3. Schumm, M. et al. (2006) Determination of residual T- and B-cell content after immunomagnetic depletion: proposal for flow cytometric analysis and results from 103 separations. Cytotherapy 8: 465–472.
  4. D’Asaro, M. et al. (2010) V gamma 9V delta 2 T lymphocytes efficiently recognize and kill zoledronate-sensitized, imatinib-sensitive, and imatinib-resistant chronic myelogenous leukemia cells. J. Immunol. 184: 3260–3268.
  5. Kordelas, L. et al. (2008) Improved overall survival in patients recovering with high gamma/delta T cells after allogeneic haematopoietic stem cell transplantation. Blood 112: Abstract 2223.
  6. Godder, K.T. et al. (2007) Long term disease-free survival in acute leukemia patients recovering with increased gammadelta T cells after partially mismatched related donor bone marrow transplantation. Bone Marrow Transplant. 39: 751–757.
  7. Knight, A. et al. (2010) The role of Vδ2-negative γδ T cells during cytomegalovirus reactivation in recipients of allogeneic stem cell transplantation. Blood 116: 2164–2172.
  8. Aversa, F. et al. (2005) Full haplotype-mismatched hematopoietic stem-cell transplantation: a phase II study in patients with acute leukemia at high risk of relapse. J. Clin. Oncol. 23: 3447–3454
  9. Handgretinger, R. et al. (2011) Transplantation of TcRαβ/CD19 Depleted Stem Cells From Haploidentical Donors: Robust Engraftment and Rapid Immune Reconstitution In Children with High Risk Leukemia. Blood 118: Abstract 1005.
  10. Anderson, B. E. et al. (2003) Memory CD4+ T cells do not induce graft-versus-host disease. J. Clin. Invest. 112: 101–108.
  11. The EBMT Handbook 6th Edition, Haematopoietic Stem Cell Transplantation, 2012
  12. Gonzalez-Vicent, M. et al. (2010) Graft manipulation and reduced-intensity conditioning for allogeneic hematopoietic stem cell transplantation from mismatched unrelated and mismatched/haploidentical related donors in pediatric leukemia patients. J. Pediatr. Hematol. Oncol. 32: 85–90.
  13. Lang, P. et al. (2005) A comparison between three graft manipulation methods for haploidentical stem cell transplantation in pediatric patients: preliminary results of a pilot study. Klin. Padiatr. 217: 334–348.
  14. Lang, P. et al. (2011) Bone Marrow Transplant. 46 (Suppl. 1): 559.
  15. Handgretinger, R. et al. (2008) The history and future prospective of haplo-identical stem cell transplantation .Cytotherapy 10: 443–451.
  16. Lang, P. et al. (2008) Bone Marrow Transplant. 42 (Suppl. 2): 54–59.
  17. Bethge, W. A. et al. (2008) Haploidentical allogeneic hematopoietic cell transplantation in adults using CD3/CD19 depletion and reduced intensity conditioning: an update. Blood Cells Mol. Dis. 40: 13–19.
  18. Federmann et al. (2009) Bone Marrow Transplant. 43 (Suppl. 1): S66.
  19. Federmann, B. et al. (2011) Immune reconstitution after haploidentical hematopoietic cell transplantation: impact of reduced intensity conditioning and CD3/CD19 depleted grafts. Leukemia 25: 121–129.
  20. Bader, P. et al. (2011) Rapid immune recovery and low TRM in haploidentical stem cell transplantation in children and adolescence using CD3/CD19-depleted stem cells. Best Pract. Res. Clin. Hematol. 24: 331–337.
  21. Schumm, M. et al. (2011) Bone Marrow Transplant. 46 (Suppl. 1): 1093.

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