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Abstract: PO1845

Glomerular Galactose-Deficient IgA1 Expression Analysis in Pediatric Patients with Glomerular Diseases

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Ishiko, Shinya, Kobe University Graduate School of Medicine, Kobe, Japan
  • Nozu, Kandai, Kobe University Graduate School of Medicine, Kobe, Japan
  • Fujimaru, Rika, Osaka City General Hospital, Osaka, Japan
  • Shima, Yuko, Wakayama Medical University, Wakayama, Wakayama, Japan
  • Kaito, Hiroshi, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
  • Tanaka, Ryojiro, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
  • Ishimori, Shingo, Takatsuki General Hospital, Takatsuki, Japan
  • Aoto, Yuya, Kobe University Graduate School of Medicine, Kobe, Japan
  • Sakakibara, Nana, Kobe University Graduate School of Medicine, Kobe, Japan
  • Nagano, China, Kobe University Graduate School of Medicine, Kobe, Japan
  • Horinouchi, Tomoko, Kobe University Graduate School of Medicine, Kobe, Japan
  • Yamamura, Tomohiko, Kobe University Graduate School of Medicine, Kobe, Japan
  • Ninchoji, Takeshi, Kobe University Graduate School of Medicine, Kobe, Japan
  • Nakanishi, Koichi, University of Ryukyus, Nishihara, Japan
  • Yoshikawa, Norishige, Takatsuki General Hospital, Takatsuki, Japan
  • Iijima, Kazumoto, Kobe University Graduate School of Medicine, Kobe, Japan
Background

Galactose-deficient IgA1 (Gd-IgA1) has been identified as a key molecule in the pathogenesis of IgA nephropathy (IgAN). Using a Gd-IgA1-specific monoclonal antibody (KM55), glomerular Gd-IgA1 deposition has been detected in patients with IgAN and IgA vasculitis with nephritis (IgAV-N), but not other glomerular diseases. However, this specificity is controversial and there are currently no studies in pediatric cases.

Methods

We conducted a retrospective, multicenter study to examine double-immunofluorescence staining of IgA and Gd-IgA1 (KM55) in 60 pediatric patients with various glomerular diseases.

Results

Glomerular Gd-IgA1 deposition was detected in all cases of IgAN (n=17/17) and IgAV-N (n=6/6), and in patients with immunocomplex-mediated glomerulonephritis, including lupus nephritis (n=9/9), membranoproliferative glomerulonephritis (n=3/4), and membranous nephropathy (n=1/1). However, Gd-IgA1 was negative in patients with non-immune related glomerular diseases with IgA deposition, including idiopathic nephrotic syndrome (n=6/6), oligomeganephronia (n=2/2), Alport syndrome (n=1/1), dense deposit disease (n=1/1), and crescentic glomerulonephritis (n=1/1). Both IgA and Gd-IgA1 were negative in patients with idiopathic nephrotic syndrome (n=5/5), membranoproliferative glomerulonephritis, membranous nephropathy, oligomeganephronia, Alport syndrome, C3 glomerulonephritis, poststreptococcal acute glomerulonephritis, and hemolytic uremic syndrome (n=1/1 each).

Conclusion

Gd-IgA1-positivity in patients with IgAN and IgAV-N was consistent with previous reports. However, Gd-IgA1 was also positive in patients with IgA-positive immunocomplex-mediated glomerulonephritis. KM55 may have the potential to distinguish incidental IgA deposition in pediatric cases. We speculate that Gd-IgA1 may be involved in the pathogenesis of these immune-related diseases, or KM55 may recognize IgA-related immunocomplex nonspecifically.