Atypical anti-glomerular basement membrane disease superimposed on IgA nephropathy

Abstract

Anti-glomerular basement membrane (anti-GBM) disease is an autoimmune disorder characterized by crescentic glomerulonephritis, pulmonary hemorrhage, and the presence of circulating anti-GBM antibodies which bind to the α3 chain of Type IV collagen found in the GBM. IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide. The simultaneous occurrence of atypical anti-GBM disease and IgAN has not been reported previously. We report here two female patients who presented with oliguria, hypertension, and renal failure. Renal biopsy revealed crescentic glomerulonephritis and bright linear IgG staining along glomerular capillary walls and mesangial IgA (3+) deposits in immunofluorescence. Serology was negative for anti-GBM antibodies both by ELISA and immunoblot assays. Hence, a diagnosis of atypical anti-GBM disease with superimposed IgAN was made. Both patients were treated with hemodialysis, intravenous steroids, and cyclophosphamide with the improvement of renal function in one patient and the other progressed to end-stage renal disease.