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Stem cell transplantation across major genetic barriers
1Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel. yair.reisner@weizmann.ac.il
Annals of the New York Academy of Sciences
|July 19, 2001
Summary
Megadose haploidentical transplants achieve engraftment without graft-versus-host disease (GVHD) thanks to veto cells. These cells, particularly cytotoxic T lymphocytes (CTLs), require simultaneous FasL and CD8 expression for their function.
Area of Science:
- Immunology
- Transplantation Biology
- Cellular Immunology
Background:
- Megadose haploidentical stem cell transplants offer rapid and durable engraftment.
- Graft-versus-host disease (GVHD) remains a significant challenge in allogeneic transplantation.
- In vitro studies suggest veto cells within hematopoietic progenitors may prevent GVHD.
Purpose of the Study:
- To investigate the mechanism by which veto cells facilitate engraftment without GVHD.
- To identify the cellular components and molecular requirements for veto cell activity.
Main Methods:
- In vitro studies using hematopoietic progenitors.
- Experiments in mice involving gene deficiencies (FasL, Fas).
- Gene transfer of FasL and administration of anti-CD8 antibody.
Main Results:
- Veto cells, particularly third-party reactive cytotoxic T lymphocytes (CTLs), promote allogeneic engraftment.
- Veto activity of CTLs is dependent on the simultaneous expression of FasL and CD8.
- Absence or manipulation of FasL or CD8 impacts veto cell function.
Conclusions:
- Veto cells, especially CTLs expressing both FasL and CD8, are crucial for successful haploidentical transplantation without GVHD.
- Understanding veto cell mechanisms can lead to improved transplant strategies.
- Targeting FasL and CD8 pathways may enhance transplant outcomes and reduce GVHD.