IgG4-related kidney disease and retroperitoneal fibrosis: An update

Abstract

The most representative kidney lesion of IgG4-related disease (IgG4-RD) is plasma cell-rich tubulointerstitial nephritis (TIN) with distinctive imaging findings including multiple low-density lesions on contrast-enhanced computed tomography. In addition, membranous glomerulonephritis is a representative glomerular lesion of this disease. Recent advances have clarified that inflammation with IgG4-positive plasma cell infiltrates is not restricted to the renal parenchyma, but can be seen in outside the renal capsule, around medium-sized arteries such as lobar arteries, around nerves, and in the renal pelvis and periureter. Hypocomplementemia is a very important feature of IgG4-TIN, and serum complement level might serve as a convenient biomarker to predict relapse. Although good responsiveness to glucocorticoid has been considered characteristic of IgG4-RD, delayed start of treatment is associated with partial scarring in the kidneys on imaging study. Therefore, steroid therapy should be immediately initiated as soon as the diagnosis of IgG4-TIN is made. Future analyses of pathogenesis will be needed to more precisely define the optimal therapeutic strategies for the various subsets of Ig4-RD patients.

Keywords:

• IgG4
• IgG4-related kidney disease
• tubulointerstitial nephritis
• membranous glomerulonephritis

Acknowledgments

The authors thank Mr. John Gelblum for his critical reading of the manuscript.

Conflict of interest

None.

Additional information

Funding

This work was supported by Health and Labour Sciences Research Grants for the Study of Intractable Diseases from the Ministry of Health, Labour and Welfare, Japan.