Influence of hematopoietic microchimerism in organ tolerance after kidney or heart transplantation

Presence of donor-and-recipient-derived DNA microchimerism in the cell-free blood samples of renal transplantation recipients associates with the acceptance of transplanted kidneys

“…The present study used a larger number of renal recipients and longer observation post-transplantation period than previous studies. There are several case reports indicating that a microchimerism-positive finding in the recipients of renal transplantation is an index of acceptance of transplanted kidney, as shown by relative longer survival time of transplanted kidneys in the recipients [6,8,10]. Tajik et al [6] documented that among the 20 recipients in their study only 3 recipients had an episode of acute rejection during the first week after transplantation, and all were in the non-microchimerism group.…”

“…Microchimerism was detected in 13 (65%) of the 20 recipients. Among the 60 kidney transplant recipients, examined for up to 1.5 years, Pujal et al [10] found 43.7% with microchimerism. Microchimerism-positive rates in both studies were significantly lower than those in the present study ( Table 2).…”

“…Tajik et al [6] documented that among the 20 recipients in their study only 3 recipients had an episode of acute rejection during the first week after transplantation, and all were in the non-microchimerism group. Pujal et al [10] analyzed 51 renal transplant recipients for rejection within 18 months (1.5 years) and found that 11.5% of microchimerism-positive recipients showed rejection, whereas 28% of microchimerismnegative recipients showed rejection. The preliminary findings from these two small case studies were further confirmed by the present, large-case study ( Table 2).…”

“…In addition, the positive correlation of microchimerism with the acceptance of the transplanted organs was also evident in recipients with other organ transplants. Pujal et al [10] analyzed 17 heart recipients and found a microchimerism-positive rate of 47% (8 of 17) in these patients. The rejection rate was 25% in the microchimerismpositive recipients and 57% in the microchimerism-negative patients (P < 0.05).…”

“…In summary, the detection of donor-DNA from the blood of recipients with renal transplantation was positively associated with the immunotolerance of transplanted organs in the recipients. Although the exact mechanisms by which microchimerisms were formed remain largely unknown [10][11][12][13][14][15], the microchimerism were proposed to be derived from kidney cells, organcontained leukocytes or blood stem cells [15]. From a clinical view, the microchimerism might be one of several immunological mechanisms that lead to long-term graft survival.…”