Microchimerism in renal allografts: clinicopathological associations according to the type of chimeric cells.
OBJECTIVE
Recent studies have highlighted the presence of microchimerism in various solid allografts. The biological significance of these chimeric cells is controversial. They may be beneficial, leading to better tolerance of grafts or participating in tissue repair or, in contrast, deleterious if involved in chronic lesions. The aim was to assess the frequency and cellular nature of microchimerism in female renal grafts of male recipients by combined fluorescence in situ hybridization (FISH) for Y chromosome and immunohistochemistry and to investigate associations between intragraft microchimerism and histological lesions or allograft outcome.


RESULTS
We screened 33 renal biopsy specimens, including 11 with acute T-cell-mediated rejection and nine with transplant glomerulopathy, from 22 male recipients transplanted with female kidneys by FISH and immunohistochemistry with antibodies against smooth muscle actin (mesangial cells), CD31 (endothelial cells), KL1 (epithelial cells), CD45 (leucocyte common antigen) and glomerular epithelial protein 1 (podocytes). Tubular microchimerism was detected in 71% of the patients with a mean percentage of chimeric epithelial cells of 1.4%. Glomerular microchimerism involving podocytes, mesangial and endothelial cells was present with a mean number of chimeric cells per glomerular section of, respectively, 0.6, 2.66 and 3.53. There was an association between endothelial microchimerism and a previous episode of acute T-cell-mediated rejection.


CONCLUSIONS
In conclusion, microchimerism in renal grafts occurs frequently, but at a low level and affects tubular cells and all glomerular cell compartments in human renal allografts.
Ferlicot
Sophie
S
Service d'Anatomie et de Cytologie Pathologiques, Université Paris-Sud 11, APHP Hôpital de Bicêtre, Le Kremlin-Bicêtre, France. sophie.ferlicot@bct.aphp.fr
Vernochet
Amélia
A
Romana
Serge
S
Ortin-Serrano
Monique
M
Letierce
Alexia
A
Brégerie
Olivier
O
Durrbach
Antoine
A
Guettier
Catherine
C
D001706:Biopsy; D046528:Chimerism; D041322:Chromosomes, Human, Y / Q000235:genetics; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005921:Glomerulonephritis / Q000235:genetics*; D006084:Graft Rejection / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D016030:Kidney Transplantation / Q000473:pathology* / Q000502:physiology; D007684:Kidney Tubules / Q000378:metabolism* / Q000473:pathology; D008297:Male; D050527:Mesangial Cells / Q000378:metabolism* / Q000473:pathology; D050199:Podocytes / Q000378:metabolism* / Q000473:pathology; D012737:Sex Factors; D013601:T-Lymphocytes; D014184:Transplantation, Homologous