Igg4-associated nephropathy N11.8

Most frequent renal (partial) manifestation of an autoimmunological IgG4-associated disease. IgG4-associated nephropathy manifests as tubulointerstitial nephritis and manifests either as chronic renal insufficiency or in a foudroyant form also with acute renal failure.

Neither incidence nor prevalence are known.

So far unsolved

Mostly male, older adults (average age 56 years: Singh N et al. 2018)

Typically, there is non-nephrotic proteinuria, hematuria, and complement depletion. In addition, (pseudotumorous) renal space-occupying lesions are found, often bilaterally and detectable in multiples (Bledsoe JR et al 2018). Associated autoimmunologic hemolytic anemia has been described (Gou SJ et al. 2018).

Serum levels of IgG and IgG4 are high, hypocomplementary, often highly elevated IgE; hematoeosinophilia.

In addition to the typical IgG4-positive plasma cell infiltrate, there is a pronounced interstitial fibrosis and a deposition of immune complexes (detection of IgG and complement in direct immunofluorescence) along the tubular basement membrane (Pradhan D et al. 2015).

Good response to glucocorticoids; typical tendency to relapse; to what extent rituximab will be a complementary alternative will have to be tested on a larger collective (Quattrocchio G et al. 2018).

Despite the typically good response to glucocorticoids (high recurrence rate) in all IgG4-associated diseases, renal fibrosis or atrophy due to delayed diagnosis can lead to chronic renal failure.

Glomerular involvement (membranous glomerulonephritis - MGN) is possible. This so-called MGN form is negative for the phospholipase A2 receptor in contrast to the classical form in immunohistochemistry.

1. Gou SJ et al (2018) Immunoglobulin G4-related Kidney Disease Associated With Autoimmune Hemolytic Anemia. Iran J Kidney Dis 12: 243-246. https://www.ncbi.nlm.nih.gov/pubmed/30087220
2. Herwig Pieringer H et al (2014) IgG4- related disease: an orphan disease with many faces Orphanet Journal of Rare Diseases 9:110
3. Bledsoe JR et al (2018) IgG4-related disease: review of the histopathologic features, differentialdiagnosis, and therapeutic approach. APMIS 126:459 476. https://www.ncbi.nlm.nih.gov/pubmed/29924455
4. Quattrocchio G et al (2018) IgG4-related kidney disease: the effects of a Rituximab-based immunosuppressive therapy. Oncotarget 9:21337-21347. https://www.ncbi.nlm.nih.gov/pubmed/29765543
5. Pradhan D et al (2015) IgG4-related kidney disease--A review. Pathol Res Pract 211:707-711. https://www.ncbi.nlm.nih.gov/pubmed/26341570
6. Singh N et al (2018) Spectrum of IgG4-related Kidney Disease at a Tertiary Care Center. Indian J Nephrol 28: 209-214. https://www.ncbi.nlm.nih.gov/pubmed/29962671