Microchimerism in peripheral blood and urine in renal transplant recipients: preliminary results

The role of microchimerism in peripheral blood and urine of renal transplant recipients remains a matter of debate, depending on the sensitivity of the methods used for detection. We studied 17 female renal transplant recipients who had received renal allografts from male donors. Polymerase chain reaction (PCR) was applied to blood and urine for the microsatellite markers D1S80, DYZ1, TH01, and kalphai SE33. Detection of DYZ1 that is present only on the Y chromosome was considered proof for microchimerism. No microchimerism was detected in peripheral blood, whereas it could be detected in the urine of 8/17 (48%) patients. There were no differences between patients with and without microchimerism regarding patient age, dialysis vintage, immunosuppression, time post-transplantation, and allograft function as measured using serum creatinine, creatinine clearance, and proteinuria. Two patients in each group showed chronic allograft dysfunction. These findings raise questions regarding the role of microchimerism in renal transplantation.