T cell depletion
As T-cell depletion is known method for removal of T lymphocytes from blood stem cell preparations (bone marrow or Leukapherisat) prior to bone marrow or stem cell transplantation to prevent graft-versus-host disease (GvH) or graft-versus-host disease (English GvHD or Graft-versus-Host Disease). T-cell depletion is a form of cell depletion .
technology
A wide variety of processes have been used over the years, of which only a few are currently in use. A method that is frequently used in Germany is depletion with the CliniMACS system from Miltenyi Biotec. The T cells are recognized by antibodies, which are directed against the CD3 antigen on T cells and are coupled to magnetic particles, and are separated from the other cells of the blood stem cell donation in a magnetic field.
Stem cell enrichment
The enrichment of stem cells with antibodies against CD34 or AC133 with the CliniMACS system ( Miltenyi Biotec ) is also a form of T cell depletion, since T cells are not selected and thus indirectly removed. This method is usually more effective in reducing T cells than T cell depletion itself.
Other procedures
Complement-based methods
Antibodies bind to the T cells and activate the complement system. This destroys the T cells.
Campath in the bag and Campath iv: Campath recognizes the CD52 antigen, which is also expressed on T cells, among other things.
ATG: (Anti-Thymocyte Globulin) The globulin fraction from a polyclonal serum against T cells.
SRBC rosetting
Sheep red blood cells, which have a natural receptor for T cells (CD2), are mixed with the bone marrow and form so-called rosettes. They are then separated by density gradient centrifugation over Percoll or Ficoll . Previously used method with high cell losses and low efficiency.
Lectin agglutination
Separation with plant lectins, often done in conjunction with SRBC rossetting.
meaning
T-cell depletion enables blood stem cell transplantation even in HLA-incompatible situations, i.e. H. when an HLA-identical donor is not available. A haploidentical transplant is then carried out by one of the parents, especially in children. Half of the HLA antigens are always identical (haplo-identical).
In addition, T-cell depletion is sometimes carried out during autologous blood stem cell transplantation in patients with autoimmune diseases in order to remove the diseased T-cells from the transplant.
Individual evidence
- ↑ Schumm: Cytotherapy. 8 (5): 465-472, 2006.