title: Immuno-histological analysis of dendritic cells in nasal biopsies of IgA nephropathy patients.
abstract: BACKGROUND
  IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Intranasal vaccination of patients with IgAN has shown mucosal and systemic IgA hyporesponsiveness. Here, we investigated whether this IgA hyporesponse in IgAN patients can be explained by reduced numbers or altered subset distribution of dendritic cells (DCs) in nasal mucosa.
  
  
  METHODS
  Eighteen IgAN patients and 18 healthy volunteers were recruited for this study. Nasal biopsies were taken, after local anaesthesia, from the lower edge of the inferior turbinate. Staining for different subsets of DCs was performed using specific monoclonal antibodies. To detect myeloid DCs, we used CD1a, DC-SIGN and blood dendritic cell antigen-1 (BDCA-1) as a marker and for plasmacytoid DCs we used BDCA-2. DC-cell numbers in the epithelium and in lamina propria were counted separately and expressed as positively stained cells per mm(2).
  
  
  RESULTS
  Both myeloid and plasmacytoid DC could be demonstrated in nasal biopsies. Quantification showed that IgAN patients contained significantly more DC-SIGN-positive cells in the lamina propria compared to controls. In addition, in IgAN patients, we observed more CD1a-positive cells in the epithelium. No differences in BDCA-1 and BDCA-2-positive cells were found between patients and controls. The number of positively stained cells in the epithelial layer correlated strongly with the number of positively stained cells in the lamina propria.
  
  
  CONCLUSIONS
  Patients with IgAN have higher numbers of CD1a-positive cells in the epithelial layer and more DC-SIGN-positive cells in the lamina propria. Therefore, the earlier observed IgA hyporesponsiveness in IgAN patients after mucosal vaccination cannot be explained by lower numbers of nasal DCs.
authors.affiliation: Department of Nephrology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: Eijgenraam
authors.forename: Susanne M
authors.initials: SM
authors.lastname: Reinartz
authors.forename: Sylvia W A
authors.initials: SW
authors.lastname: Kamerling
authors.forename: Vanessa J
authors.initials: VJ
authors.lastname: van Ham
authors.forename: Kim
authors.initials: K
authors.lastname: Zuidwijk
authors.forename: Cornelis M
authors.initials: CM
authors.lastname: van Drunen
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: Daha
authors.forename: Wytske J
authors.initials: WJ
authors.lastname: Fokkens
authors.forename: Cees
authors.initials: C
authors.lastname: van Kooten
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D002452:Cell Count; D003713:Dendritic Cells / Q000473:pathology*; D005260:Female; D005922:Glomerulonephritis, IGA / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000473:pathology*