Related Experiment Videos
Critical re-evaluation of 41 cases of "idiopathic" crescentic glomerulonephritis
F Ferrario1, M T Tadros, P Napodano
1Department of Nephrology, S. Carlo Borromeo Hospital, Milan, Italy.
Insights
Idiopathic rapidly progressive glomerulonephritis (RPGN) is heterogeneous. This study identified two distinct subgroups based on histology, immunofluorescence, and clinical presentation, aiding in better classification and understanding of RPGN.
Area of Science:
- Nephrology
- Pathology
- Immunology
Background:
- "Idiopathic crescentic GN" lacks precise definition within rapidly progressive glomerulonephritis (RPGN) classifications, suggesting underlying heterogeneity.
- Existing classifications do not adequately define patients with RPGN lacking systemic disease, anti-GBM antibodies, or primary glomerulopathy.
- Understanding the distinct characteristics of "idiopathic RPGN" is crucial for accurate diagnosis and treatment.
Purpose of the Study:
- To retrospectively analyze clinical, histological, and immunopathological features of 41 patients diagnosed with "idiopathic RPGN".
- To identify and define distinct subgroups within "idiopathic RPGN" based on morphological and clinical characteristics.
- To improve the classification and understanding of heterogeneous "idiopathic RPGN" cases.
Main Methods:
- Retrospective analysis of 41 patients with "idiopathic RPGN" (no systemic disease, anti-GBM GN, or defined primary GN).
- Morphological review to define subgroups based on intraglomerular necrosis and Bowman's capsule rupture.
- Histological, immunofluorescence (C3, IgG), and clinical data (proteinuria, ANCA status) analysis for each subgroup.
Main Results:
- Group I (n=25): Characterized by intraglomerular necrosis, frequent Bowman's capsule rupture, minimal endocapillary proliferation, interstitial infiltrates, mild sclerosis. 64% showed C3 deposits; 92% were ANCA-positive with mean 1.8 g/day proteinuria.
- Group II (n=16): Characterized by no intracapillary necrosis, marked mesangial proliferation, scarce interstitial infiltrates, no Bowman's capsule rupture, and marked glomerulosclerosis/fibrosis. All had C3/IgG deposits; 50% had prior urinary abnormalities with mean 4.5 g/day proteinuria and ANCA-negative.
- Two distinct subgroups of "idiopathic RPGN" were identified with differing histological, immunopathological, and clinical profiles.
Conclusions:
- "Idiopathic crescentic GN" represents at least two distinct clinicopathological entities.
- Group I aligns with pauci-immune glomerulonephritis, often ANCA-associated.
- Group II exhibits features suggestive of immune-complex mediated glomerulonephritis, requiring further investigation.
Abstract:
Despite the availability of different classifications for rapidly progressive glomerulonephritis (RPGN), patients with "idiopathic crescentic GN" have not been yet inserted as a precisely defined subgroup, pointing to their probable heterogenicity. Trying to better define their characteristic, we retrospectively analyzed the clinical, histological and immunopathological features of 41 patients diagnostically labelled "idiopathic RPGN" because they had no evidence of systemic disease (including systemic vasculitis), no anti-GBM mediated glomerulonephritis and no clearly defined primary glomerulopathy. Starting by a thorough morphological review, 2 subgroups were defined: group I (25 patients) with variable degrees of intraglomerular necrosis, and group II (16 patients) with no intracapillary necrotizing lesions. Group I showed no or minimal endocapillary proliferation, intense interstitial infiltrates with periglomerular localization, frequent ruptures of Bowman's capsule and mild degree of glomerular and/or interstitial sclerosis. 16 patients in this group (64%) had irregular deposits of complement C3 at immunofluorescence while the remaining 9 (36%) had no immune deposits. Clinically they had no previous history of preceding urinary abnormalities, had a mean of 1.8 g/day proteinuria and a positivity for ANCA in 92% (12/13). In group II there was frequently marked mesangial proliferation, scarce interstitial infiltrates, no ruptures of Bowman's capsule and marked degrees of glomerulosclerosis and interstitial fibrosis. All patients in this group had clearly defined immune deposits of C3 and/or IgG. Clinically 50% of these patients had a history of recurrent microhematuria and/or proteinuria, a mean of 4.5 g/day proteinuria and negativity for ANCA in all 8 patients tested.(ABSTRACT TRUNCATED AT 250 WORDS)