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Sivadas S, Narayanan R, Kurien AA, Abdulla MC. DNAJB9-Associated Fibrillary Glomerulonephritis and Immunoglobulin A Nephropathy - A Rare Combination. Indian J Nephrol 2024; 34:276-277. [PMID: 39114401 PMCID: PMC11302112 DOI: 10.4103/ijn.ijn_101_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 04/25/2023] [Indexed: 08/10/2024] Open
Affiliation(s)
- Sajeesh Sivadas
- Department of Nephrology, Aster MIMS Hospital, Kotakkal, Kerala, India
| | - Ranjit Narayanan
- Department of Nephrology, Aster MIMS Hospital, Kotakkal, Kerala, India
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Muto R, Maeda K, Fukui S, Saito S, Kato N, Kosugi T, Shimizu A, Maruyama S. IgA-dominant glomerulonephritis with DNAJB9-negative fibrillar polytypic immunoglobulin deposits in the subepithelium. CEN Case Rep 2022:10.1007/s13730-022-00759-2. [PMID: 36576710 PMCID: PMC10393911 DOI: 10.1007/s13730-022-00759-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 11/21/2022] [Indexed: 12/29/2022] Open
Abstract
Fibrillary glomerulonephritis (FGN), a rare disease is pathologically characterized by glomerular fibril accumulation ranging from 12 to 24 nm in diameter with negative Congo red staining. Recently, the identification of DnaJ homolog subfamily B member 9 (DNAJB9) as a highly sensitive and specific marker for FGN has revolutionized diagnosis of this disease. However, few recent studies have reported DNAJB9-negative glomerulonephritis with fibrillar deposits. As such, it remains unclear whether DNAJB9-negative cases can be considered equivalent to FGN. Here, we report the case of a 70-year-old woman who developed renal impairment and nephrotic-range proteinuria. Renal biopsy and pathological examination revealed focal glomerulonephritis with fibrocellular crescents. Immunofluorescence microscopy showed IgA-dominant deposition of polytypic IgG in the glomerulus. Electron microscopy revealed hump-like subepithelial electron dense deposits with fibrils of 15-25 nm in diameter. These findings were consistent with FGN; thus, Congo red and direct fast scarlet (DFS) staining, and immunohistochemistry for DNAJB9 were performed. In addition to negative Congo red/DFS/DNAJB9 staining, laser microdissection (LMD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) resulted negative for DNAJB9, which is a highly sensitive and specific marker for FGN. The patient's renal function further declined, prompting administration of rituximab weekly for 2 weeks, similar to the treatment for FGN. This is a unique case of IgA-dominant glomerulonephritis with DNAJB9-negative fibrillar polytypic immunoglobulin deposits in the subepithelium, unlike previous DNAJB9-negative cases. Thus, DNAJB9-negative cases diagnosed based on accurate electron microscopic evaluation must be gathered, and LMD and LC-MS/MS must be used to analyze the organized fibrillar deposits to reveal the disease entity.
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Affiliation(s)
- Reiko Muto
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
- Department of Molecular Medicine and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Kayaho Maeda
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
| | - Sosuke Fukui
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Shoji Saito
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Noritoshi Kato
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Tomoki Kosugi
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Shoichi Maruyama
- Department of Nephrology, Nagoya University Graduate School of Medicine, 65 Tsuruma-Cho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
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Gambella A, Pitino C, Barreca A, Nocifora A, Giarin MM, Bertero L, Biancone L, Roccatello D, Papotti M, Cassoni P. DNAJB9 Is a Reliable Immunohistochemical Marker of Fibrillary Glomerulonephritis: Evaluation of Diagnostic Efficacy in a Large Series of Kidney Biopsies. Biomedicines 2022; 10:biomedicines10092102. [PMID: 36140202 PMCID: PMC9495529 DOI: 10.3390/biomedicines10092102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/25/2022] [Accepted: 08/25/2022] [Indexed: 11/21/2022] Open
Abstract
Fibrillary glomerulonephritis (FGN) is a rare glomerular disease characterized by a challenging diagnostic workup requiring ultrastructural identification of 20 nm-thick randomly oriented fibrillar deposits. However, the recent introduction of DNAJB9 as a putative diagnostic marker of FGN could thoroughly improve this diagnostic scenario. This study aims to assess the DNAJB9 immunohistochemical expression in a large series of FGN cases and to eventually confirm its role as a diagnostic marker of FGN. We evaluated the immunohistochemical expression of DNAJB9 (Rabbit Polyclonal, ThermoFisher) in a series of 77 FGN and 128 non-FGN cases diagnosed between January 1992 and June 2022 at the Pathology Unit of the AOU Città della Salute e della Scienza Hospital. DNAJB9 was expressed in 73 of the 74 evaluable FGN cases, mostly showing a strong glomerular positivity (68 cases). Additionally, DNAJB9 resulted positive in all challenging scenarios [early-stage (6), congophilic (4), combined (4), and uncertain (4) cases of FGN)]. DNAJB9 was negative in all non-FGN cases, eventually resulting in a specificity of 100% and sensitivity of 99%. In conclusion, we confirmed the role of DNAJB9 as a diagnostic marker of FGN. Its adoption in the clinical routine will allow a faster, more feasible, and more accurate FGN diagnosis.
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Affiliation(s)
- Alessandro Gambella
- Pathology Unit, Department of Medical Sciences, University of Turin, 10126 Turin, Italy
| | - Chiara Pitino
- Pathology Unit, Department of Medical Sciences, University of Turin, 10126 Turin, Italy
| | - Antonella Barreca
- Pathology Unit, “Città della Salute e della Scienza di Torino” University Hospital, Via Santena 7, 10126 Turin, Italy
- Correspondence:
| | - Alberto Nocifora
- Pathology Unit, “Città della Salute e della Scienza di Torino” University Hospital, Via Santena 7, 10126 Turin, Italy
| | - Manuela Maria Giarin
- Pathology Unit, “Città della Salute e della Scienza di Torino” University Hospital, Via Santena 7, 10126 Turin, Italy
| | - Luca Bertero
- Pathology Unit, Department of Medical Sciences, University of Turin, 10126 Turin, Italy
| | - Luigi Biancone
- Division of Nephrology Dialysis and Transplantation, “Città della Salute e della Scienza di Torino” University Hospital, Department of Medical Sciences, University of Turin, 10126 Turin, Italy
| | - Dario Roccatello
- CMID, Coordinating Center of the Network for Rare Diseases of Piedmont and Aosta Valley, Nephrology and Dialysis Unit (ERK-Net Member), San Giovanni Bosco Hub Hospital, University of Turin, 10144 Turin, Italy
| | - Mauro Papotti
- Pathology Unit, Department of Oncology, University of Turin, 10126 Turin, Italy
| | - Paola Cassoni
- Pathology Unit, Department of Medical Sciences, University of Turin, 10126 Turin, Italy
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Andeen NK, Kung VL, Robertson J, Gurley SB, Avasare RS, Sitaraman S. Fibrillary Glomerulonephritis, DNAJB9, and the Unfolded Protein Response. GLOMERULAR DISEASES 2022; 2:164-175. [PMID: 36817290 PMCID: PMC9936766 DOI: 10.1159/000525542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/30/2022] [Indexed: 11/19/2022]
Abstract
Background Fibrillary glomerulonephritis (FGN) is found in approximately 1% of native kidney biopsies and was traditionally defined by glomerular deposition of fibrils larger than amyloid (12-24 nm diameter) composed of polyclonal IgG. Recent identification of DNAJB9 as a sensitive and specific marker of FGN has revolutionized FGN diagnosis and opened new avenues to studying FGN pathogenesis. In this review, we synthesize recent literature to provide an updated appraisal of the clinical and pathologic features of FGN, discuss diagnostic challenges and pitfalls, and propose molecular models of disease in light of DNAJB9. Summary DNAJB9 tissue assays, paraffin immunofluorescence studies, and IgG subclass testing demonstrate that FGN is distinct from other glomerular diseases with organized deposits and highlight FGN morphologic variants. Additionally, these newer techniques show that FGN is only rarely monoclonal, and patients with monoclonal FGN usually do not have a monoclonal gammopathy. DNAJB9 mutation does not appear to affect the genetic architecture of FGN; however, the accumulation of DNAJB9 in FGN deposits suggests that disease is driven, at least in part, by proteins involved in the unfolded protein response. Treatments for FGN remain empiric, with some encouraging data suggesting that rituximab-based therapy is effective and that transplantation is a good option for patients progressing to ESKD. Key Messages DNAJB9 aids in distinguishing FGN from other glomerular diseases with organized deposits. Further investigations into the role of DNAJB9 in FGN pathogenesis are necessary to better understand disease initiation and progression and to ultimately develop targeted therapies.
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Affiliation(s)
- Nicole K. Andeen
- Department of Pathology and Laboratory Medicine, Oregon Health & Science University, Portland, Oregon, USA,*Nicole K. Andeen,
| | - Vanderlene L. Kung
- Department of Pathology and Laboratory Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Josh Robertson
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Susan B. Gurley
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Rupali S. Avasare
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
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