Rapidly Progressive Glomerulonephritis due to Anti-glomerular Basement Membrane Disease Accompanied by IgA Nephropathy: An Unusual Association

Anti-glomerular basement membrane (anti-GBM) disease is a systemic autoimmune disorder characterized by circulating IgG antibodies (rarely IgA and IgM) to the carboxyterminal, noncollagenous 1 (NC1) domain of type IV collagen of GBM also known as Goodpasture antigen. Patients typically present with rapidly progressive glomerulonephritis (RPGN) and pulmonary hemorrhage in the presence of which it is referred to as Goodpasture's disease. Anti-GBM disease has been reported to coexist with pauci-immune antineutrophil cytoplasmic autoantibody-positive glomerulonephritis and membranous glomerulopathy. The sequential or concurrent presentation of anti-GBM disease with IgA nephropathy has been rarely described. We herein report a case of a 22-year-old female who presented with RPGN, and renal biopsy revealed crescentic glomerulonephritis with strong linear IgG (+2) staining of GBM and extensive mesangial IgA (+3) deposits. The patient was treated with three pulses of IV methylprednisolone followed by oral steroids. Plasmapheresis and cytotoxic agents were not included in the therapeutic armamentarium as the patient had no pulmonary hemorrhage and biopsy revealed established chronic changes. The association of anti-GBM disease with IgA nephropathy could open up new vistas on the implication of these IgA mesangial deposits in the pathogenesis and prognosis of anti-GBM disease.