Microchimerism in peripheral blood of recipients 10 years after renal transplantation.

Microchimerism is a phenomenon which occurs in some recipients after kidney transplantation (KT) and has been considered to play an important role to the induction or maintenance of allograft tolerance. In order to study the relevance of microchimerism to the long-term outcome of renal allograft (RA), we retrospectively analyzed the presence of microchimerism in peripheral blood (PB) of 14 male- to female kidney transplant recipients who had a stable graft function for 10 years or longer post-transplantation. Among the 287 recipients who underwent KT between 1983 and 1993, 88 (30.6%) are still functioning. Among these 88 patients, 14 male to - female RA recipients were suitable for analysis of the presence of microchimerism in PB and of their immunological status. Microchimerism was tested using nested-PCR ampli? cation for the SRY region of the Y chromosome and was detected in 12 (85.7%) of 14 cases at various intervals. Our results suggest that PB DNA chimerism is present in a significant percentage of the female recipients following KT and that the increase of chimeric status may be useful to determine long-term graft survival.