PMC5437996_01
A: The sampled glomeruli showed membranoproliferative features with accentuated lobulation, mesangial and frequent endocapillary hypercellularity, and duplication of the glomerular basement membranes (PAS, 400x); B: Direct immunofluorescence revealed strong granular mesangial and frequent capillary wall staining for IgM, C3, and kappa-light chains only (kappa-light chain shown, 400x); C: Electron microscopy showed numerous immune-type electron dense deposits in mesangial and subepithelial to intramembranous locations, which focally demonstrated a fibrillary to microtubular substructure (19,000x).
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Figure1
Renal biopsy performed 2 weeks later for persistently elevated creatinine revealed glomerulonephritis with a membranoproliferative pattern of injury, and several glomeruli contained small cellular to fibrocellular crescents (Figure 1A). By direct immunofluorescence, there was granular mesangial and capillary wall staining for IgM (3+), C3 (2-3+), and kappa-light chain only (3-4+) (Figure 1B). Ultrastructural evaluation revealed numerous mesangial and subendothelial deposits with a fibrillary to microtubular substructure (Figure 1C).
Clinical course with rituximab treatment. Alb = albumin; Cr = creatinine; Uprot/cr = urine protein-to-creatinine ratio.
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Figure2
Figure 2 summarizes the trends in relevant laboratory values over time.