Two-Step Allogeneic Hematopoietic Stem Cell Transplantation

The Two-Step Allogeneic Hematopoietic Stem Cell Transplantation is a specialized therapeutic protocol developed at the Sidney Kimmel Cancer Center at Thomas Jefferson University. Designed to improve outcomes for patients with high-risk hematologic malignancies who lack fully matched donors, the protocol separates the infusion of donor T cells and hematopoietic stem cells. In the first step, patients receive a fixed dose of donor CD3+ T cells following a conditioning regimen (typically total body irradiation). This is followed by the administration of high-dose cyclophosphamide on days -3 and -2 to induce T-cell tolerization, which selectively eliminates alloreactive T cells to prevent graft-versus-host disease (GVHD) while preserving T cells that provide anti-tumor and anti-infection immunity. In the second step (day 0), CD34-selected hematopoietic stem cells are infused to achieve marrow recovery. This approach allows for the use of partially matched (haploidentical) related donors and aims to optimize the graft-versus-tumor effect while minimizing transplant-related toxicity.

Other names

Jefferson Two-Step ProtocolTwo-Step HSCTTwo-Step Approach to Allogeneic Hematopoietic Stem Cell Transplantation