An improved method for T-cell depletion of allogeneic histoincompatible donor bone marrow

Area of Science:

• Hematology
• Immunology
• Transplantation Science

Background:

• Acute graft-versus-host disease (GVHD) is a major obstacle in allogeneic bone marrow transplantation for leukemia and aplastic anemia.
• GVHD is primarily mediated by T cells present in the harvested bone marrow, ranging from 5-50% of the mononuclear cell population.

Purpose of the Study:

• To evaluate the efficacy of T cell depletion (TCD) using E-rosetting for reducing GVHD in allogeneic bone marrow transplantation.
• To assess the impact of TCD on bone marrow cell viability, T cell removal efficiency, and stem cell engraftment.

Main Methods:

• T cell depletion of human bone marrow using E-rosetting with modified sheep erythrocytes for 24 hours at 4°C.
• Cytofluorographic analysis using anti-T cell monoclonal antibodies to quantify T cell removal and Ia+ cell enrichment.
• Assessment of mononuclear cell viability and stem cell engraftment in adult patients.

Main Results:

• E-rosetting achieved greater than or equal to 97% removal of T cells and abrogated T cell activity.
• TCD bone marrow mononuclear cells demonstrated >99% viability and a twofold enrichment for Ia+ cells.
• Successful engraftment was achieved with as few as 4 X 10(8) total mononuclear cells, indicating TCD does not impede stem cell engraftment.

Conclusions:

• E-rosetting is an effective and simpler method for T cell depletion compared to lectin column or monoclonal antibody/complement lysis techniques.
• This TCD method shows promise in ameliorating GVHD, potentially expanding the application of allogeneic bone marrow transplantation.
• The procedure maintains high cell viability and does not interfere with crucial stem cell engraftment processes.