Dendritic Cells in Hematopoietic Cell Transplantation

Dendritic cells (DCs) are hematopoietic cells that belong to the antigen-presenting cell (APC) family, which also includes B cells and macrophages. DCs represent 1-5% of tissue cells depending on the organ and include two major subsets, the CD103+CD11b- and the CD11b+ DC subsets. Tissue inflammatory reactions such as those induced by graft-versus-host disease (GVHD) may also increase the presentation capacity of non-professional APCs, enhancing local inflammation. Two factors play a role in determining donor chimerism of DCs in the tissues which includes the radiosensitivity or extent of depletion by conditioning, and the alloreactivity of donor T cells in the graft. Animal models confirm the importance of recipient APCs in the GVL response. DCs are potential therapeutic targets in the peri and post-transplant settings. Antibodies such as CMRF-44 recognize activated DCs in any site and are able to lyse blood DCs and LCs in the presence of complement.