Quantitative Polymerase Chain Reaction Detection of Microchimerism in Female Transplant Renal Recipients

Introduction: Microchimerism (MC) is the presence of a small amount of foreign cells or DNA within a person's circulation or tissues. It has been identified also in recipients of solid organ transplants where it seems to be critical for the development and maintenance of immunological tolerance. Nevertheless, natural and/or iatrogenic MC can be acquired prior to transplantation, through pregnancy and/or blood transfusion. Objective: The aim of this study was to detect the presence of MC in women after renal transplantation from male cadaveric donors and its relationship with graft outcomes. Methods: We studied by qPCR the presence of the DYS14 gene sequence of the Y chromosome in 12 females who received a kidney graft from a male donor before transplantation (T0), after 15 days (T1) and 1 year of transplantation (T2). We found the sequence in all recipients after renal transplantation. Results: All the women were negative for this sequence prior to transplantation (T0). Mean (SD) Y-related DNA quantity was 0.80 (0.69) ng/mL plasma and 0.15 (0.26) ng/mL plasma at T1 and T2, respectively. No acute rejection was observed, and mean (SD) estimated Cr clearance was 68.8 (16.9) mL/min within 1 year from transplantation. Conclusions: Presence of MC was associated with good kidney graft outcomes after 1 year of transplantation, but further studies will be needed to investigate the relationship between clinical outcomes and the development of MC in renal transplant recipient.