Table 3.

HLA typing and immune suppression. As discussed in the text cells may be less immunogeneic than tissues or organs and this has raised that possibility that with HLA matching no immune suppression will be required. The argument for and against this are summarized. For a detailed discussion the reader is directed to the references that discuss these issues in detail

Will HLA typing allow us to eliminate use of immunosuppressants?
YES– Because	No– Because
• Cells are less immunogenic than organs or tissue	• But nevertheless cells are immunogenic
• Data that immune suppression can be removed	• However in kidney and islets these data are controversial
• Data that fetal cells can tolerate some degree of mismatch	• True but only limited mismatch tolerated
• Many target therapies are in immune privileged sites	• However, blood and other non immune privileged sites being considered
• Embryonic cells have low or no MHC expression	• Embryonic cells will elevate expression after transplantation and in cases of sensitization or immune activation
• Cells may have localized immune modulatory activity	• True but this may be overcome when homeostasis changes

If foreign protein expressed then immune suppression to that antigen will be required