Thymic Irradiation Is Required for Transplantation Tolerance After TLI/ATS Non-Myeloablative Conditioning

Allogeneic hematopoietic stem cell transplantation after immunosuppressive but non-myeloablative conditioning: "miniallografts" are no small matter.

Thymic recovery after allogeneic hematopoietic cell transplantation with non-myeloablative conditioning is limited to patients younger than 60 years of age.

BACKGROUND Long-term immune recovery in older patients given hematopoietic cell transplantation after non-myeloablative conditioning remains poorly understood. This prompted us to investigate long-term lymphocyte reconstitution and thymic function in 80 patients given allogeneic peripheral blood stem cells after non-myeloablative conditioning. DESIGN AND METHODS Median age at transplant was 5...

Non-myeloablative transplantation.

The concept of utilizing enhanced immunosuppression rather than myeloablative cytotoxic conditioning has allowed the engraftment of allogeneic stem cells from related and unrelated donors with lower early transplant-related mortality (TRM) and morbidity. This approach shifts tumor eradication to the graft-vs-host immune response directed against minor histocompatibility antigens expressed on tu...

Peyer patches are not required for acute graft-versus-host disease after myeloablative conditioning and murine allogeneic bone marrow transplantation.

Graft-versus-host disease (GVHD) is a multistep disease process following allogeneic bone marrow transplantation (BMT). It has been postulated that the induction of acute GVHD requires the presence of Peyer patches (PPs). A new tumor necrosis factor (TNF)-deficient strain has been developed that totally lacks PPs and displays the defects characteristic of TNF ablation but not lymphotoxin-associ...

Prevalence of chimerism after non-myeloablative hematopoietic stem cell transplantation.

CONTEXT AND OBJECTIVE Non-myeloablative hematopoietic stem cell transplantation (NMA-HSCT) is performed in onco-hematological patients who cannot tolerate ablative conditioning because of older age or comorbidities. This approach does not completely eliminate host cells and initially results in mixed chimerism. Long-term persistence of mixed chimerism results in graft rejection and relapse. Inv...