For the therapeutic administration of human ES cells
to be an option, the rejection of the cells by the immune
system will have to be addressed. Although the immune
response should be less intense than the response to
xenotransplants, the major histocompatibility complex
differences between human ES cells and a recipient will
require immunosuppression. The extent to which immunosuppression
will be necessary for the transplantation of
cells into the inner ear must be determined, because the
inner ear might display the immune privilege that is
observed in the brain [64].