Early microchimerism in peripheral blood following kidney transplantation

Background: The role of microchimerism found in the peripheral blood of renal transplant recipients remains a matter of debate. We assessed the frequency of microchimerism after kidney transplantation and examined its influence on clinical courses over a 12-month follow-up period.

Patients and methods: Ten single-kidney recipients underwent microchimerism detection at 2 days, 2 weeks, and 1, 3, 6, and 12 months after transplantation, with mismatch human leukocyte antigen (HLA)-A, -B, and -C used as markers.

Results: Microchimerism was detected in 8 (80%) patients at 2 days after kidney transplantation. In 3 of those, microchimerism became negative within 3 months after transplantation, whereas it remained present for up to 12 months in 3 patients (33 %). There was 1 acute rejection episode in a patient in whom microchimerism became negative within 3 months. Protocol renal graft biopsy specimens obtained 3 months after transplantation revealed no acute cellular-mediated rejection (ACMR) or acute antibody-mediated rejection (AAMR) in the 5 patients positive for microchimerism at 3 months.

Conclusions: Microchimerism was frequently detected after kidney transplantation. Microchimerism that remained for more than 3 months post-transplantation might be correlated with a lower incidence of rejection, thus its monitoring may help identify recipients with a low rejection risk.