Urinary myeloid IgA Fc alpha receptor (CD89) and transglutaminase-2 as new biomarkers for active IgA nephropathy and henoch-Schönlein purpura nephritis

Rafael N Moresco; Marijn M Speeckaert; Slawomir C Zmonarski; Magdalena Krajewska; Ewa Komuda-Leszek; Agnieszka Perkowska-Ptasinska; Loreto Gesualdo; Maria T Rocchetti; Sigurd E Delanghe; Raymond Vanholder; Wim Van Biesen; Joris R Delanghe

doi:10.1016/j.bbacli.2016.02.002

Urinary myeloid IgA Fc alpha receptor (CD89) and transglutaminase-2 as new biomarkers for active IgA nephropathy and henoch-Schönlein purpura nephritis

BBA Clin. 2016 Feb 17:5:79-84. doi: 10.1016/j.bbacli.2016.02.002. eCollection 2016 Jun.

Affiliations

¹ Department of Clinical and Toxicological Analysis, Federal University of Santa Maria, Santa Maria, Brazil; Department of Clinical Chemistry, Ghent University Hospital, Gent, Belgium.
² Department of Nephrology, Ghent University Hospital, Gent, Belgium.
³ Department of Nephrology and Transplantation Medicine, Wroclaw Medical University, Wroclaw, Poland.
⁴ Department of Transplantation Medicine and Nephrology, Medical University of Warsaw, Warsaw, Poland.
⁵ Department of Emergency and Organ Transplantation, Section of Nephrology, University of Bari "Aldo Moro", Bari, Italy.
⁶ Department of Clinical Chemistry, Ghent University Hospital, Gent, Belgium.

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.

Keywords: Henoch-Schönlein purpura nephritis; IgA nephropathy; Myeloid IgA Fc alpha receptor; Transglutaminase-2.