Rejecting tissue and organ grafts shed cellular debris from damaged cells. Cellular debris contains fragments of nuclei with their genetic material. The question arises what is the fate of donor DNA in recipient fluids and tissues. Is it enzymatically disintegrated and becomes a waste product or it is utilized by recipient cells. We have shown, using sex-mismatched transplants and the Sry-gene fragment PCR detection method, that at the time of rejection recipient tissue contain donor DNA. The concentration of donor DNA did not parallel the concentration of live donor passenger cells. There were differences in donor DNA concentration depending on whether heart, skin or BMC were transplanted. Moreover, there was more donor DNA in recipient tissues than in control syngeneic transplants. Interestingly, a relatively high donor DNA concentration was detected in syngeneic recipients reflecting the extent of non-immune pre-transplantation ischemic damage of the graft.

Keywords: DNA, Macrophages, lymphoid tissues, allogeneic transplants