High frequency of epithelial chimerism in liver transplants demonstrated by microdissection and STR-analysis

Abstract

It has recently been shown that epithelial cells derived from stem cells originating outside the liver are integrated into liver allografts. Whether epithelial intragraft chimerism protects transplants from rejection or chronic transplant dysfunction, and whether it interferes with recurrence of primary liver disease, is not known. Twenty-seven sequential biopsies derived from 9 liver-transplant recipients were studied for chimerism of hepatocytes and cholangiocytes. The target cells were isolated by laser microdissection after cytokeratin immunolabeling and genotyped using DNA analysis of a highly polymorphic short tandem repeat. Irrespective of whether early (up to 4 weeks) or late (more than 12 months) posttransplantation biopsies were studied, cholangiocyte chimerism was almost constantly found in 91% of the samples. No significant differences occurred between samples derived from patients with chronic organ dysfunction (n ‫؍‬ 3), recurrent hepatitis (n ‫؍‬ 3), or mild, unspecific changes (n ‫؍‬ 3). By contrast, hepatocyte chimerism tended to occur later (55% vs. 22%) and appeared to be associated with recurrent hepatitis (67% vs. 27%). In this respect, chronic organ dysfunction did not differ from mild, unspecific changes. While cholangiocyte chimerism represents a constant and early phenomenon in liver transplantations, an enhanced chimeric integration of recipient-derived hepatocytes can be observed in recurrent hepatitis, supporting the concept of an increased recruitment of extrahepatic progenitor cells to the liver in chronic hepatitis. (HEPATOLOGY 2002;35:110-116.)

Quantitative Gene Expression Analysis Reveals Transition of Fetal Liver Progenitor Cells to Mature Hepatocytes after Transplantation in uPA/RAG-2 Mice

“…10 -12 Generation of hepatocytes from bone marrow cells also occurs after allergenic liver transplantation in humans and is associated with the frequency and severity of rejection episodes. 37 The molecular events, however, inducing differentiation and transdifferentiation in adult and embryonic/fetal stem cells are primarily unknown. Stage-and differentiation-specific gene expression patterns with quantitative PCR and genome-wide technologies may be helpful in unraveling the underlying molecular mechanisms and will be crucial for developing in vitro differentiation protocols for stem cell populations.…”

Chimerism of Metanephric Adenoma but Not of Carcinoma in Kidney Transplants

“…Fragments of laser-destroyed cells do not cause contamination of STR-PCR as shown previously. 5,6 Chimerism-negative tumors could be taken as controls that indicate elimination of the contamination problem by the methodological approach applied. Furthermore, we confirmed our STR-PCR results by X chromosome in situ hybridization revealing tumor cells with a XX karyotype in allografts from male donors in a female recipient.…”

“…[5][6][7][8]13 To exclude any contamination of the following PCR analysis by infiltrating recipient cells, an immunohistochemical stain for leukocytes and histiocytes combining antibodies against CD45 and CD68 (both DAKO, Hamburg, Germany) was performed following a standard ABC technique. 8 Laser-based microdissection of pure epithelial tumor cell populations were performed using the PALM Laser MicroBeam system (P.A.L.M., Bernried, Germany).…”

“…We combined laser-microdissection of pure tumor cell populations with genotyping (DNA fingerprinting). [5][6][7][8] This approach enabled analysis of all allografts independent of gender mismatch. In two cases, in which the recipient and donor were of different gender, we detected sex chromosomes by in situ hybridization to confirm short tandem repeat (STR)-polymerase chain reaction (PCR) results.…”

“…Examples include renal tubular epithelial cells, endothelial cells, interstitial myofibroblast, hepatocytes, bile duct epithelial cells, cardiomyocytes, pneumocytes, and bronchial epithelial cells. [1][2][3][4][5][6][7][8][9][10][11] Chimerism in organ transplantation is not only generated by recipient-derived stem cells, but also can originate from a spread of graft cells beyond the transplanted organ. Mazal and colleagues 12 showed that donor-derived tubular epithelial cells from renal transplants are the source for nephrogenic adenomas arising in the urinary bladder of allograft recipients.…”