Immunotherapy after hematopoietic stem cell transplantation using umbilical cord blood-derived products

Umbilical cord blood (UCB) is being increasingly used as a source of hematopoietic stem cells (HSC) for transplantation. UCB transplantation (UCBT) has some advantages such as less stringent HLA-matching requirements, fast availability of the graft and reduced incidence and severity of graft-versus-host disease. However, UCBT is also associated with a higher incidence of infection, graft failure, slow engraftment and slow immune reconstitution. UCB is mainly used as a source of HSC; however, it is also rich in immune cells that could be used to treat some of the main complications post-UCBT as well as other diseases, thus implicating the use of UCB for immunotherapy. Here, we aim to describe some of the therapies currently developed that use UCB as a cell source, focusing in particular on regulatory T cells and natural killer cells.