Considering the common sources of stem cells, are the risks of rejection the same from each source?
Autologous stem or progenitor cells stored earlier by the recipient or obtained during a surgical procedure from the recipient have the least risk of rejection, provided they do not become contaminated during processing or handling so that the body recognizes them as foreign, rather than part of itself. If the cells can be re-programmed to be the “appropriate” cell type they have the highest probability for success. Stem cells of fetal, embryonic, or cord blood origin express lower amounts of antigens that might cause transplant rejection and therefore may be more suitable and require fewer immune suppression drugs in the patients who receive them compared to unrelated (allogeneic) cells or tissues (from other, unrelated people) or from animal (xenogeneic) cell or tissue donors.
