[Immunonegative necrotizing glomerulonephritis: an atypical case of lupus nephropathy].

We report here a case of systemic lupus erythematosus with severe, active pauci-immune necrotizing and crescentic glomerulonephritis. This patient had been diagnosed of a lupus nephritis type III previously and treated with steroids and azathioprine. After a renal symptomless period of nine years, she developed heavy proteinuria and hypertension. A second kidney biopsy was then performed. The pathological study disclosed a pauci-immune necrotizing crescentic and segmental glomerulonephritis. The absence of subendothelial and mesangial deposits was confirmed by both immunofluorescent microscopy and electron microscopy. The simultaneous immunological study showed normal ANCA levels while complement, anti-dsDNA and ANA were altered. The patient was treated with steroids and cyclophosphamide eith good response. This case points out the possibility previously recognized by others of an association between lupus and an pauci-immune necrotizing glomerulonephritis.