title: In vivo reflectance confocal microscopy of the skin: a noninvasive means of assessing body cystine accumulation in infantile cystinosis.
abstract: BACKGROUND
  Patients with infantile nephropathic cystinosis have progressive accumulation of cystine in tissues leading to delayed extrarenal complications. No simple tool is available to evaluate the level of body cystine accumulation.
  
  
  OBJECTIVE
  We sought to determine the value of in vivo reflectance confocal microscopy of the skin in patients with infantile nephrogenic cystinosis.
  
  
  METHODS
  Nine patients and control subjects were recruited for this study. Images were acquired by means of a near-infrared reflectance confocal laser scanning microscope.
  
  
  RESULTS
  Scattered bright particles within the papillary dermis were observed in all patients but not in control subjects. The density of particles ranged from numerous (+++) to very few (+/-) and their distribution was heterogeneous. Electron microscopy confirmed that these particles corresponded to cystine crystal deposits within dermal fibroblasts. The density of cystine crystals within the dermis was greater in older patients, in patients with a high leukocyte cystine concentration, and with delayed cysteamine therapy. There was no correlation between the density of cystine deposits and renal disease or hypopigmentation but high levels of deposition occurred in association with extrarenal manifestations.
  
  
  CONCLUSIONS
  This is a preliminary study on a small sample of patients. Repeated examination and longer follow-up is necessary.
  
  
  CONCLUSIONS
  In vivo reflectance confocal microscopy of the skin appears to be a noninvasive means of assessing body cystine accumulation in infantile cystinosis and could be used as a complementary marker of treatment response in addition to leukocyte cystine measurement.
authors.affiliation: Department of Dermatology, Archet 2 Hospital, Nice, France; INSERM U895 Team 1, Nice, France. Electronic address: chiaverini.c@chu-nice.fr.
authors.forename: Christine
authors.initials: C
authors.lastname: Chiavérini
authors.affiliation: Department of Dermatology, Archet 2 Hospital, Nice, France.
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Kang
authors.affiliation: Department of Dermatology, Archet 2 Hospital, Nice, France.
authors.forename: Laura
authors.initials: L
authors.lastname: Sillard
authors.affiliation: Department of Pediatric Nephrology, Archet 2 Hospital, Nice, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Berard
authors.affiliation: Department of Pediatric Nephrology, Necker Hospital, Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Niaudet
authors.affiliation: Department of Pediatric Nephrology, Necker Hospital, Paris, France.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Guest
authors.affiliation: Timone Hospital, Marseille, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Cailliez
authors.affiliation: Department of Dermatology, Archet 2 Hospital, Nice, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bahadoran
authors.affiliation: Department of Dermatology, Archet 2 Hospital, Nice, France.
authors.forename: Jean Philippe
authors.initials: JP
authors.lastname: Lacour
authors.affiliation: INSERM U895 Team 1, Nice, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Ballotti
authors.affiliation: Department of Dermatology, Archet 2 Hospital, Nice, France.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Ortonne
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003553:Cystine / Q000032:analysis* / Q000378:metabolism; D003554:Cystinosis / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D055815:Young Adult
chemical_list: D003553:Cystine