The chief job of our immune system is to distinguish "self" versus "non-self" so that our immune system can attack anything that ought not to be there. This creates obvious problems when organs are transplanted from one person to another and means that most recipients of transplanted organs must take immunosuppressive drugs for the rest of their lives. Living in an immune suppressed state allows the body to accept a new organ, but make the recipient susceptible to bacterial and viral infections.

Jennifer and I attended a symposium put on by the Stanford Medical School about advances in stem cell technology. Dr. Irving Weissman, Professor of Cancer Biology at Stanford, described a new transplantation protocol that has worked 100% of the time in mice:

1. Irradiate the transplant recipient to destroy the blood forming stem cells

2. Transplant blood marrow, which has been purified to eliminate the T-cells, from the transplant donor to the recipient.

3. Transplant an organ from the donor to the recipient.

An amazing thing then happens: the donor's immune system takes root in the recipient. This means that there is no need for immunosupressive drugs to guard against organ rejection because the transplanted immune system sees the transplanted organ as "self."

This is very awe inspiring technology, but it begs a existential question:

The immune system's job is to distinguish between "self" and "non-self." I have received an immune system from someone else: Who do I perceive myself to be?

New technologies continue to bring new hope but also new questions.

-Tim
1:20:19 PM