Detection of donor DNA after heart transplantation: how far could it be affected by blood transfusion and donor chimerism?

The possibility to detect donor DNA in recipient plasma has been discussed as a method to prove organ rejection without a biopsy. Usually, the presence of Y chromosome-specific DNA sequences in female recipients has been used as an example. We have analyzed the presence of part of Y chromosomes in females after heart transplantation. The results suggested that pretransplantation blood transfusion together with cell chimerism of donor organs could be factors that affect detection of donor DNA in recipient plasma. Among females who have undergone transplantation, if the donor organ is chimeric, nested polymerase chain reaction may permit detection of Y chromosome-specific DNA sequences to estimate rejection. In other cases, extremely well-controlled methods using multiple markers need to be developed to avoid the danger of false-positive or false-negative results.