title: Urinary myeloid IgA Fc alpha receptor (CD89) and transglutaminase-2 as new biomarkers for active IgA nephropathy and henoch-Schönlein purpura nephritis.
abstract: BACKGROUND
  IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis (HSPN) are glomerular diseases that share a common and central pathogenic mechanism. The formation of immune complexes containing IgA1, myeloid IgA Fc alpha receptor (FcαRI/CD89) and transglutaminase-2 (TG2) is observed in both conditions. Therefore, urinary CD89 and TG2 could be potential biomarkers to identify active IgAN/HSPN.
  
  
  METHODS
  In this multicenter study, 160 patients with IgAN or HSPN were enrolled. Urinary concentrations of CD89 and TG2, as well as some other biochemical parameters, were measured.
  
  
  RESULTS
  Urinary CD89 and TG2 were lower in patients with active IgAN/HSPN compared to IgAN/HSPN patients in complete remission (P < 0.001). The CD89xTG2 formula had a high ability to discriminate active from inactive IgAN/HSPN in both situations: CD89xTG2/proteinuria ratio (AUC: 0.84, P < 0.001, sensitivity: 76%, specificity: 74%) and CD89xTG2/urinary creatinine ratio (AUC: 0.82, P < 0.001, sensitivity: 75%, specificity: 74%). Significant correlations between urinary CD89 and TG2 (r = 0.711, P < 0.001), proteinuria and urinary CD89 (r = - 0.585, P < 0.001), and proteinuria and urinary TG2 (r = - 0.620, P < 0.001) were observed.
  
  
  CONCLUSIONS
  Determination of CD89 and TG2 in urine samples can be useful to identify patients with active IgAN/HSPN.
authors.affiliation: Department of Clinical and Toxicological Analysis, Federal University of Santa Maria, Santa Maria, Brazil; Department of Clinical Chemistry, Ghent University Hospital, Gent, Belgium.
authors.forename: Rafael N
authors.initials: RN
authors.lastname: Moresco
authors.affiliation: Department of Nephrology, Ghent University Hospital, Gent, Belgium.
authors.forename: Marijn M
authors.initials: MM
authors.lastname: Speeckaert
authors.affiliation: Department of Nephrology and Transplantation Medicine, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Slawomir C
authors.initials: SC
authors.lastname: Zmonarski
authors.affiliation: Department of Nephrology and Transplantation Medicine, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Krajewska
authors.affiliation: Department of Transplantation Medicine and Nephrology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Komuda-Leszek
authors.affiliation: Department of Transplantation Medicine and Nephrology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Perkowska-Ptasinska
authors.affiliation: Department of Emergency and Organ Transplantation, Section of Nephrology, University of Bari "Aldo Moro", Bari, Italy.
authors.forename: Loreto
authors.initials: L
authors.lastname: Gesualdo
authors.affiliation: Department of Emergency and Organ Transplantation, Section of Nephrology, University of Bari "Aldo Moro", Bari, Italy.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Rocchetti
authors.affiliation: Department of Nephrology, Ghent University Hospital, Gent, Belgium.
authors.forename: Sigurd E
authors.initials: SE
authors.lastname: Delanghe
authors.affiliation: Department of Nephrology, Ghent University Hospital, Gent, Belgium.
authors.forename: Raymond
authors.initials: R
authors.lastname: Vanholder
authors.affiliation: Department of Nephrology, Ghent University Hospital, Gent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Van Biesen
authors.affiliation: Department of Clinical Chemistry, Ghent University Hospital, Gent, Belgium.
authors.forename: Joris R
authors.initials: JR
authors.lastname: Delanghe
keywords: Henoch-Schönlein purpura nephritis; IgA nephropathy; Myeloid IgA Fc alpha receptor; Transglutaminase-2