<p><b>BACKGROUND</b>The
blood vessels of a transplanted organ are the interface between
donor and recipient. The
endothelium in the
blood vessels is
thought to be the major target for
graft rejection.
Endothelial cells of a transplanted organ can be of recipient origin after
transplantation. In this study, we tested whether endothelial
chimerism correlated with the
graft rejection and
cold ischemia.</p><p><b>
METHODS</b>We studied the
biopsy samples from 34 renal
transplants of
female recipients
who received the
kidney from a
male donor for the presence of
endothelial cells of recipient origin. We examined the
tissue sections of renal
biopsy samples by fluorescence in situ hybridization (FISH) for the presence of
endothelial cells containing two
X chromosomes using a biotinylated
Y chromosome probe and
digoxigenin labelled
X chromosome probe, and then analyzed the relationship between the
endothelial cell chimerism and the rejection and
cold ischemia.</p><p><b>RESULTS</b>Endothelial
chimerism was common and irrespective of rejections (P > 0.05). The
cold ischemic time of
chimerism group was longer than no
chimerism group ((14.83 +/- 4.03) hours vs (11.27 +/- 3.87) hours, P < 0.05).</p><p><b>CONCLUSIONS</b>There is no correlation between the percentage of recipient
endothelial cells in
vascular endothelial cells and the type of
graft rejection. The
endothelium damaged by ischemic
injury might be repaired by the
endothelial cells from the recipient.</p>