High prevalence of microchimerism in female patients.

Evaluation of free plasma DNA has been suggested as one of the option to detect organ rejection in transplanted patients. However, the presence of chimeric cells in organs could make this approach complicated. To study the presence of Y-chromosome chimeric cells, we examined biopsy samples of 40 thoracic aortas of female donors and recipients. Using nested polymerase chain reaction, the presence of Y-chromosome-specific DNA sequences was detected in 19 (47.5%) analyzed tissue samples. Thus, free DNA originating from more than two genomes could be present in plasma in such a high proportion of cases. This phenomenon makes the use of plasma free DNA for the detection of organ rejection difficult and impractical.

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.

[Cell-free human DNA in body fluids--potential for clinical applications]. / Volná (nebunená) lidská DNA v telních tekutinách--moznosti klinického vyuzití.

Despite being discovered long time ago--in the 50th of the previous century, the existence of free cell human DNA in different body fluids is getting its importance only in the last decade. The presence of the free cell human DNA in different body fluids gives us new opportunities in diagnosis and/or in follow up of different diseases or clinical settings. Being a relatively new method, even its methodology is waiting to be standardized, as well its clinical role under different clinical courses. The aim of this text is to review the current literature concerning free cell DNA importance under different clinical situations.