Distribution and components of interstitial inflammation and fibrosis in IgG4-related kidney disease: analysis of autopsy specimens

Satoshi Hara, Mitsuhiro Kawano, Ichiro Mizushima, Kenichi Harada, Takuma Takata, Takako Saeki, Yoshifumi Ubara, Yasuharu Sato, Michio Nagata

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

IgG4-related kidney disease (IgG4-RKD) occasionally progresses to chronic renal failure and is pathologically characterized by IgG4-positive lymphoplasmacyte-rich tubulointerstitial nephritis with storiform fibrosis (bird's-eye pattern fibrosis). Although radiology reveals a heterogeneous distribution of affected areas in this disease, their true distribution within the whole kidney is still unknown because of difficulty in estimating this from needle biopsy samples. Using 5 autopsy specimens, the present study histologically characterized the distribution and components of interstitial inflammation and fibrosis in IgG4-RKD. Interstitial lymphoplasmacytic infiltration or fibrosis was observed in a variety of anatomical locations such as intracapsular, subcapsular, cortical, perivascular, and perineural regions heterogeneously in a patchy distribution. They tended to be more markedly accumulated around medium- and small-sized vessels. Storiform fibrosis was limited to the cortex. Immunostaining revealed nonfibrillar collagens (collagen IV and VI) and fibronectin predominance in the cortical lesion, including storiform fibrosis. In contrast, fibril-forming collagens (collagen I and III), collagen VI, and fibronectin were the main components in the perivascular lesion. In addition, α-smooth muscle actin–positive myofibroblasts were prominently accumulated in the early lesion and decreased with progression, suggesting that myofibroblasts produce extracellular matrices forming a peculiar fibrosis. In conclusion, perivascular inflammation or fibrosis of medium- and small-sized vessels is a newly identified pathologic feature of IgG4-RKD. Because storiform fibrosis contains mainly nonfibrillar collagens, “interstitial fibrosclerosis” would be a suitable term to reflect this. The relation between the location and components of fibrosis determined in whole kidney samples provides new clues to the pathophysiology underlying IgG4-RKD.

Original languageEnglish
Pages (from-to)164-173
Number of pages10
JournalHuman Pathology
Volume55
DOIs
Publication statusPublished - Sep 1 2016

Keywords

  • Bird's-eye pattern fibrosis
  • IgG4-related disease
  • IgG4-related kidney disease
  • Interstitial fibrosis
  • Storiform fibrosis

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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