Crescentic Glomerulonephritis With Immunoglobulin G4-Related Disease

Immunoglobulin G4 (IgG4)-related disease is an uncommon autoimmune disease that affects multiple organ systems. Renal involvement typically presents as tubulointerstitial nephritis and less commonly as membranous glomerulonephritis. In this case report, we discuss a 68-year-old patient who presented with rapidly progressive glomerulonephritis. His renal biopsy revealed a membranoproliferative pattern of injury with fibrocellular crescents and extensive infiltration of the tubulointerstitium with IgG4-positive plasma cells. We treated the patient with both corticosteroids and rituximab because of the aggressive nature of crescentic glomerulonephritis. The patient demonstrated a partial improvement in kidney function after 2 cycles of rituximab with a decrease in serum creatinine levels from 6.9-4.7mg/dL after 6 months from presentation. This case illustrates the importance of considering IgG4-related disease in cases of rapidly progressive glomerulonephritis and the need for effective treatments for more aggressive forms of this recently recognized disease entity.