RESUMO
<p><b>AIM</b>To examine whether the existence of the donor-and recipient-derived DNA chimerism in recipient's plasma can be a predictive marker for the status of transplanted organ.</p><p><b>METHODS</b>One hundred and twenty-six female patients who had been transplanted with male kidneys were enrolled in the present study. In these female recipients, the SRY(1), DYZ(1)(1st) and DYZ(1)(2nd) genes on the Y chromosome from the plasma were prospectively examined using reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>SRY, DYZ(1)(1st) and DYZ(1)(2nd) sequences were detected in the cell-free blood (plasma) of 97 (77%) of 126 female patients with male kidney. The average time that the transplanted kidneys functioned was 8.7 years and 5.4 years among microchimerism-positive and microchimerism-negative recipients, respectively. The frequency of the patients who had acute rejection after renal transplantation was approximately 10% and 28% in microchimerism-positive and microchimerism-negative recipients, respectively. Serum creatinine levels in microchimerism-positive patients were significantly lower than those in microchimerism-negative patients.</p><p><b>CONCLUSION</b>These results suggest that plasma DNA microchimerism present in certain patients following renal transplantation and measurement of plasma DNA microchimerism using quantitative RT-PCR might be a useful predictor for the acceptance of transplanted kidneys.</p>