Cell Therapy in Solid-Organ Transplant.

In solid-organ transplant, cell therapy is used as an immunomodulation therapy or as a functioning graft (bioengineering medicine). Before such treatment can be more accepted among transplant societies, some uncertainties should be clarified. These include: why is such therapy mandatory? What are the indications for this therapy, and what are the mechanism(s) of actions? What types of cells are involved and what are their routes of actions? Finally, what is known about the safety? In general, the risks associated with intravenous administration of immunoregulatory cell products are similar to those encountered with conventional blood transfusions. The adverse effects of immunosuppressive drugs, such as infections, cardiovascular disease, metabolic complications, and malignancies, would be decreased with cell therapy. Immunoregulatory cells act when necessary and through multiple mechanisms through different targets. Immunoregulatory cells are not only passive inhibitors such as drugs, but they have active functions. Treatment would only be once or perhaps a few times but not indefinitely, which is in contrast to immunosuppressive drugs; therefore, complications involving immunosuppressive drugs are no longer present. Cell therapy in solid-organ transplant is indicated for treatment of ischemic-reperfusion injury, prevention of chronic allograft nephropathy, minimization of immune suppression, and induction of long-term allograft tolerance. Many cell types have being investigated as potential cell-based immunotherapies for use in solid-organ transplant, including mesenchymal stromal cells, regulatory macrophages, tolerogenic dendritic cells, regulatory T cells, and regulatory B cells. Efficacy and safety of each group of cells should be clarified before widespread clinical use. The landscape of transplant science would be at least partially, if not totally, changed with cell therapy.