ANCA negative pauci-immune glomerulonephritis with systemic involvement.

Systemic vasculitides (SV) are a group of diseases with multi system involvement and varied clinical presentation. Anti-neutrophil cytoplasmic antibody (ANCA) testing has high sensitivity and specificity for SV. We describe the clinical course of four patients who had pauci-immune glomerulonephritis with systemic involvement without serological ANCA positivity; they were followed up for a cumulative 55 patient months. The mean Birmingham vasculitis score score was 23. All four had systemic symptoms with arthralgias and fever (100%). Neurological manifestations were seen in two patients (66%). Accelerated hypertension was seen in one. One patient had pulmonary renal syndrome. Renal manifestation was characterized by nephrotic range of proteinuria with glomerular hematuria in all (100%) and severe renal failure requiring dialysis in three (66%). At admission the mean blood urea was 146 +/- 19 mg% and mean serum creatinine was 5.6 +/- 1.9 mg%. Renal biopsy revealed focal proliferative glomerulonephritis with crescents only in 20-30% of glomeruli. There was significant chronic interstitial involvement in two patients (66%). Therapy with pulse steroids, cyclophosphamide, and mycophenolate mofetil (MMF) was effective in three patients while one died with lung hemorrhage. In conclusion, majority of patients with ANCA negative pauci-immune glomerulonephritis have multi-system involvement at admission. Renal biopsy is characterized by focal proliferative lesions with crescents and significant chronic interstitial fibrosis. Immunosuppressive drugs in the form of corticosteroids, MMF and cyclophosphamide bring about marked renal recovery in most patients.