PMC9275406_01
Crescentic glomerulonephritis with hematoxylin and eosin stain (at x 20 magnification).
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Figure1
The kidney biopsy showed cellular and fibrous crescents with negative immunohistochemistry, in keeping with pauci-immune glomerulonephritis (Figure 1).
A: Tubulointerstitial inflammation with a predominance of IgG4-producing plasma cells in the kidney parenchyma (at x 2 magnification). B: High-powered view with immune deposit staining confirming the presence of IgG4 deposits (at x 40 magnification).
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Figure2
Surprisingly, significant tubulointerstitial inflammation was also seen with a predominance of plasma cells (Figure 2A). These were later confirmed to be IgG4-producing plasma cells on immunohistochemistry, with the presence of IgG4 deposits confirmed following immune deposit staining, and the infiltration of 10 IgG4 cells per high-power field in keeping with IgG4-related disease (Figure 2B).