Cell-based therapies

Abstract

Cell therapy describes the process of introducing new cells into a tissue in order to treat a disease. Cell therapies often focus on the treatment of hereditary diseases, with or without the addition of gene therapy. There are many potential forms of cell therapy: the transplantation of stem cells that are autologous (from the patient) or allogeneic (from another donor), the transplantation of mature, functional cells, the application of modified human cells that are used to produce a needed substance, the xenotransplantation of non-human cells that are used to produce a needed substance (e.g., treating diabetic patients by introducing insulin-producing pig cells directly into their muscle) and the transplantation of trans-differentiated cells derived from the patient's own differentiated cells (e.g., the use of insulin producing beta cells trans-differentiated from isolated hepatocytes as a treatment for diabetes). Increasingly, mesenchymal stem cells are being proposed as agents for cell-based therapies, due to their plasticity, established isolation procedures, and capacity for ex vivo expansion. For safety reasons, cell therapy of systemic sclerosis (SSc) has most commonly employed autologous hematopoietic stem cell transplantation (HSCT) to replace a previously ablated or markedly reduced lymphohematopoietic/immune system with the aim of "resetting" autoimmunity. Some cases of allogeneic HSCT and mesenchymal stem cell (MSC) transplantation have also been performed, and the results and ongoing programs of these cellular therapies will be reviewed in this chapter.