title: Renal allograft calcification -- prevalence and etiology in pediatric patients.
abstract: BACKGROUND
  Calcification of renal allografts has been reported in adult kidney transplant (KTx) recipients with a widely differing prevalence (2-60%). Persistent hyperparathyroidism, hypercalcemia and concomitant hypercalciuria were identified as major risk factors. We aimed to determine the prevalence and risk factors for such calcifications in children.
  
  
  METHODS
  We investigated histological stains of routine graft biopsies from pediatric KTx patients for renal calcifications and determined the urinary excretion of lithogenic (oxalate, calcium) and stone-inhibitory substances (citrate).
  
  
  RESULTS
  In our series of transplant patients, tubular calcification was found in 16 of the 36 (44.4%) KTx biopsies by an additional Kossa stain. This transplant calcification was not associated with any singular risk factor and was not correlated to a worse transplant outcome.
  
  
  CONCLUSIONS
  Although our pediatric findings confirm the reported incidence rates of KTx calcification in adults, we could neither identify hypercalciuria as a risk factor nor confirm any negative influence on graft function. However, long-term studies are clearly needed to prove or disprove a negative impact of calcifications on graft function.
authors.affiliation: Department of Pediatrics, Division of Pediatric Nephrology, University Hospital, Cologne, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Habbig
authors.forename: Bodo B
authors.initials: BB
authors.lastname: Beck
authors.forename: Markus
authors.initials: M
authors.lastname: Feldkötter
authors.forename: Friederike
authors.initials: F
authors.lastname: Körber
authors.forename: Charlie
authors.initials: C
authors.lastname: Laffeber
authors.forename: Carl
authors.initials: C
authors.lastname: Verkoelen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mihatsch
authors.forename: Bernd
authors.initials: B
authors.lastname: Hoppe
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D009397:Nephrocalcinosis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D015995:Prevalence; D055815:Young Adult