Microchimerism (MC) is the presence of a small amount of foreign cells or DNA within a persons circulation or tissues. In transplant recipients it seems to be critical for the development and maintenance of immunological tolerance. Nevertheless, natural and/or iatrogenic MC can also be acquired prior to transplantation, deriving from pregnancy or blood transfusion.
Aim of this study was to analyse the possible influence of donor MC after kidney transplantation for possible tolerance mechanism purposes.
We studied 12 female (mean age 47 ±8.5 years) recipients of a first renal transplant (RTR) from a male donor. All the patients recieved cyclosporine, steroids, Mycophenolate mofetil and basiliximab as induction. They were prospectively studied by a quantitative real time PCR method (qPCR) for male MC detection in plasma DNA based on the detection of the DYS14 gene sequence on the Y-chromosome. Y-related DNA sequence can be considered as a cell-death marker released from necrotic or apoptotic cells in the transplanted organ or donor-derived haemopoietic cells in the recipient's blood or other tissues.
Persistence of donor DNA in recipient plasma was assessed at day 15 and months 12 after transplantation. A pre-transplant blood sample was collected from each patient and used as negative control.
Mean serum creatinine was 1.36±0.35 mg/dl and mean GFR 74±15.5 ml/min 1 year after transplantation.
No acute rejection episode was documented.
The median of HLA mismatches was 3 (range 2-5)
No Y-related DNA was detected in pre-transplant samples.
Mean DNA quantity after 15 days resulted 0.80±0.69 ng/ml plasma corresponding to 121.8±104,8 genome equivalents/ml plasma.
A 5-fold decrease was recorded in mean plasma Y-related DNA at month 12, resulting 0.15±0.26 ng/ml plasma (23.1±40.0 genome equivalents/ml plasma). It is worth to note that most of the patients (80%) had levels of donor DNA below 10 genome equivalents/ml plasma at month 12.
Donor-specific DNA sequences are present in the plasma of all patients 15 days after transplant. A marked decrease in plasma DNA donor concentration was recorded after 1 year. We observed no acute rejection.
The absence of acute rejection episodes in these patients prevents a complete clinico-immunological correlation.
To cite this abstract in AMA style:Carta P, Zanazzi M, Pinzani P, Salvianti F, Villari D, Minetti E. PCR-Based Detection for Microchimerism and Graft Outcome in Kidney Transplant Recipients [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/pcr-based-detection-for-microchimerism-and-graft-outcome-in-kidney-transplant-recipients/. Accessed October 27, 2020.
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