Clinical efficacy of intravenous immunoglobulin for patients with MPO-ANCA-associated rapidly progressive glomerulonephritis

Background: To determinewhether intravenous immunoglobulin (IVIg) cancontrol disease activity in patients with myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-associated rapidly progressive glomerulonephritis (RPGN). Methods: Twelve patients with serologically and histologically confirmed MPO-ANCA-associated RPGN (7 men, 5 women; mean age 71 ± 3 years) received IVIg (400 mg/kg/day) alone for 5 days. The effects of IVIg were evaluated by white blood cell counts, serum C-reactive protein levels, Birmingham Vasculitis Activity Score, rate of change in reciprocal creatinine (1/Cre), and plasma tumor necrosis factor-α levels after IVIg administration. Corticosteroids with or without cyclophosphamide were commenced after IVIg. Results:After IVIg treatment, a significant decrease was observed in white blood cell count (p < 0.05), C-reactive protein values (p < 0.001), and Birmingham Vasculitis Activity Score (p < 0.001) concomitant with the amelioration of systemic symptoms. The rate of change in 1/Cre significantly improved (p < 0.05). Plasma tumor necrosis factor-α levels that were significantly elevated in patients before IVIg compared with normal controls (p < 0.0001), rapidly declined after IVIg with a significant reduction(p < 0.05). Three months post-treatment with IVIg, all patients showed improvement of disease without serious infectious complications. Conclusion: IVIg is a potential component of remission induction therapy for patients with MPO-ANCA-associated RPGN.