title: Tubular chimerism occurs regularly in renal allografts and is not correlated to outcome.
abstract: Recent studies have demonstrated an integration of recipient-derived progenitor cells into solid allografts with differentiation into parenchymal cells. Whether or to what extent this phenomenon influences allograft outcome has still to be elucidated. To detect epithelial chimerism tubular cells were harvested from sequential renal allograft biopsy samples by laser microdissection in 36 patients. Recipient-derived cells were detected by short-tandem repeat-based genotyping. In cases with gender-mismatched transplantation, chimerism was semiquantitatively evaluated by in situ hybridization for the Y-chromosome. Findings were correlated to different pathomechanisms of epithelial injury as well as to morphologic and clinical outcome. Epithelial chimerism was detectable as early as 8 d after transplantation and lasted for 8 yr. A total of 88% of the patients showed an epithelial chimerism; 72% had a stable chimerism in sequential biopsy samples. Evaluation of Y-chromosome by in situ hybridization revealed low percentages of chimerical tubular epithelial cells (2.4% to 6.6%). No correlation to morphology was found. Chimerism was detectable in inconspicuous protocol biopsy samples, cases of drug toxicity, and rejected allografts with and without chronic changes. No correlation was found to allograft function. Epithelial microchimerism is an early and persistent phenomenon after renal transplantation. There is no correlation to morphologic or functional outcome. Probably recipient-derived stem cells contribute in a minor fashion to tissue homeostasis, and cell turnover in renal allografts is predominantly enabled by donor cell renewal.
authors.affiliation: Institut fuer Pathologie, Medizinischen Hochschule Hannover, Carl Neuberg Strasse 1, 30625 Hannover, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Mengel
authors.forename: Danny
authors.initials: D
authors.lastname: Jonigk
authors.forename: Magali
authors.initials: M
authors.lastname: Marwedel
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kleeberger
authors.forename: Martin
authors.initials: M
authors.lastname: Bredt
authors.forename: Oliver
authors.initials: O
authors.lastname: Bock
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lehmann
authors.forename: Wilfried
authors.initials: W
authors.lastname: Gwinner
authors.forename: Hermann
authors.initials: H
authors.lastname: Haller
authors.forename: Hans
authors.initials: H
authors.lastname: Kreipe
mesh_terms: D001706:Biopsy; D006801:Humans; D016030:Kidney Transplantation / Q000473:pathology; D007684:Kidney Tubules / Q000166:cytology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D018183:Transplantation Chimera / Q000235:genetics; D016896:Treatment Outcome; D019459:Urothelium / Q000166:cytology* / Q000473:pathology