"Pauci-immune" proliferative and necrotizing glomerulonephritis with thrombotic microangiopathy in patients with systemic lupus erythematosus and lupus-like syndrome

In the glomerulonephritides of systemic lupus erythematosus (SLE), the numb er of subendothelial deposits, when present, generally corresponds to the d egree of light microscopic glomerular hypercellularity; only very rarely ar e no or few such deposits present in cases of focal (WHO class III) or diff use (WHO class IV) proliferative lupus nephritis, We have recently encounte red five cases of active diffuse proliferative glomerlonephritis with no su bendothelial and few or no mesangial deposits and thrombotic microangiopath y (TMA) in four patients with SLE and one patient with lupus-like syndrome. Three of the five patients were tested for circulating lupus anticoagulant s or anticardiolipin antibodies, and two were positive. All five patients t ested negatively for antineutrophil cytoplasmic antibodies (ANCA). Three pa tients responded to steroid and cyclophosphamide treatment, although one of them died of acute bacterial bronchopneumonia, One patient was lost to fol low-up. We conclude that "pauci-immune" proliferative lupus nephritis is ra re and should be treated as proliferative lupus nephritis with a proportion ate number of subendothelial deposits. The negative ANCA suggests that thes e cases do not represent incidental ANCA-associated pauci-immune necrotizin g and crescentic glomerulonephritis in patients with SLE, Of particular int erest is that, in patients with SLE, if associated with TMA, an active prol iferative necrotizing glomerulonephritis may be present even in the absence of significant glomerular immune complex deposition. (C) 2000 by the Natio nal Kidney Foundation, Inc.