[kragen]

Well, not anything. I have glass embedded in my foot which isn't being attacked, for example, and there are plenty of examples of biocompatible polymers, many of them already used in medical implants.

(By the way, all organisms are made of chiral molecules; what we're talking about is reversing the chirality.)

Some of the things the immune system uses to attack things, such as superoxide, would work fine on mirror organisms. Others, such as antibodies to existing organisms, wouldn't work at all. I don't know what the balance is.