Objective: To investigate the clinical and pathologic characteristics of anti-glomerular basement membrane(GBM) disease with normal renal function.
Methods: The clinical and pathologic data of 6 patients with anti-GBM disease and normal renal function in Peking Union Medical College Hospital were reviewed retrospectively. Furthermore, 29 patients with anti-GBM disease and impaired renal function in the same period in the same hospital were enrolled as the control group. Factors that may influence the prognosis were analyzed.
Results: Six (17.1%) of all 35 patients maintained normal renal function for 12-133 months during follow-up. Five patients had microhematuria and proteinuria, one had pulmonary hemorrhage only, and three manifested as Goodpasture syndrome. Renal biopsies from 4 patients revealed linear deposition of IgG 2+-3+ along the glomerular capillary walls by immunofluorescence. As shown by normal light microscopy, mild mesangial proliferation and crescentic glomerulonephritis with a large amount of fibrinoid necrosis of glomerular capillary walls were observed in different patients; however, most pathological changes were mild. Five of these six patients were treated with immunosuppressive drugs and/or plasma exchange. Compared with the control group, the 6 patients with normal renal function had significantly higher hemoglobin[(77.97±20.62 vs.(99.67±19.80 g/L P=0.024], lower titers of anti-GBM antibody[(224.34 ± 145.79 vs.(80.23 ± 85.73 EU/ml P=0.027], and lower ratio of glomeruli with crescents[(0.58±0.29 vs.(0.17±0.27 ,P=0.005]. These 6 patients with normal renal function were followed up for 12-133 months, among whom 4 patients achieved complete remission and 2 had mild proteinuria and microhematuria.
Conclusion: Anti-GBM disease with normal renal function is not uncommon. Most patients have mild pathologic changes and good prognosis.