Definition

A preparation of allogeneic peripheral blood stem cells (PBSCs) from an unrelated or partially matched related donor that have been selectively depleted of alpha/beta T cells and CD19-positive (CD19+) B-cells with potential immune reconstituting activity. The alpha/beta T-cell/CD19+ B-cell-depleted stem cells contain high amounts of natural killer (NK) cells, gamma/delta T cells, CD34+ stem cells, and dendritic cells (DCs), while devoid of alpha/beta T-cells and CD19-positive B cells. Depletion of alpha/beta T cells, which are implicated in the adaptive immune response that mediates graft-versus-host disease (GvHD), may promote rapid and sustained engraftment, immune reconstitution, and may prevent or reduce the development of GvHD. The depletion of CD19+ B cells may reduce the risk of Epstein-Barr virus (EBV)-driven post-transplant lymphoproliferative disorders. The retained CD3+ gamma/delta T cells and NK cells may synergistically exert an anti-leukemic and antiviral effector function, which may further promote engraftment and immune reconstitution.