Utility of glomerular Gd-IgA1 staining for indistinguishable cases of IgA nephropathy or Alport syndrome

Shinya Ishiko, Akihito Tanaka, Asami Takeda, Masayuki Hara, Naoto Hamano, Masahiro Koizumi, Toshinori Ueno, Hiroki Hayashi, Atsushi Kondo, Sadayuki Nagai, Yuya Aoto, Nana Sakakibara, China Nagano, Tomoko Horinouchi, Tomohiko Yamamura, Takeshi Ninchoji, Yuko Shima, Koichi Nakanishi, Norishige Yoshikawa, Kazumoto IijimaKandai Nozu

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Pathological findings in Alport syndrome frequently show mesangial proliferation and sometimes incidental IgA deposition, in addition to unique glomerular basement membrane (GBM) changes including thin basement membrane and/or lamellation. However, similar GBM abnormalities are also often observed in IgA nephropathy. Both diseases are also known to show hematuria, proteinuria, and sometimes macrohematuria when associated with viral infection. Therefore, it can be difficult to make a differential diagnosis, even based on clinical and pathological findings. Some recent articles demonstrated that galactose-deficient IgA1 (Gd-IgA1)-specific monoclonal antibody (KM55) could potentially enable incidental IgA deposition to be distinguished from IgA nephropathy. Methods: We performed comprehensive gene screening and glomerular Gd-IgA1 and type IV collagen α5 chain immunostaining for five cases with both IgA deposition and GBM changes to confirm that Gd-IgA1 can help to distinguish these two diseases. Results: Four of the cases were genetically diagnosed with Alport syndrome (Cases 1–4) and one was IgA nephropathy with massive GBM changes, which had a negative gene test result (Case 5). In Cases 1–4, glomerular Gd-IgA1 deposition was not detected, although there was positivity for IgA in the mesangial area. In Case 5, glomerular Gd-IgA1 deposition was observed. Conclusion: Gd-IgA1 expression analysis could clearly differentiate these two disorders. This approach can be applied to identify these two diseases showing identical clinical and pathological findings.

Original languageEnglish
Pages (from-to)779-787
Number of pages9
JournalClinical and Experimental Nephrology
Volume25
Issue number7
DOIs
Publication statusAccepted/In press - 2021

All Science Journal Classification (ASJC) codes

  • Physiology
  • Nephrology
  • Physiology (medical)

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