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Muthukumaran A, Wanchoo R, Seshan SV, Gudsoorkar P. Paraneoplastic Glomerular Diseases. ADVANCES IN KIDNEY DISEASE AND HEALTH 2024; 31:346-357. [PMID: 39084760 DOI: 10.1053/j.akdh.2024.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/25/2024] [Accepted: 04/30/2024] [Indexed: 08/02/2024]
Abstract
Paraneoplastic glomerular disease (PGD) develops from tumor cell products, leading to renal dysfunction. Unlike direct tumor effects, PGD illustrates the complex association between cancer and diverse clinical presentations and outcomes. Initially detected in a Hodgkin's disease patient, current research has defined diagnostic criteria based on PGD symptoms and cancer progression. PGDs, although rare (found in <1% of adult cancer patients with overt renal manifestations), are crucial, as they can signal cancer onset and frequently resist standard glomerulonephritis treatments. The emerging field of onconephrology studies this relationship between kidney disorders and cancers. The exact cause of many PGD cases remains unknown. This review examines PGDs, their clinicopathological features, related cancers, and mechanisms, emphasizing the need for early diagnosis and tailored treatment for kidney disease and linked cancer.
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Affiliation(s)
- Aarthi Muthukumaran
- Division of Nephrology, Hammersmith Hospital, Imperial College Healthcare, NHS, London, UK
| | - Rimda Wanchoo
- Division of Kidney Diseases and Hypertension, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Great Neck, NY
| | - Surya V Seshan
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY
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2
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Viejo-Boyano I, Moreno-Abenza G, Álvarez-Muñoz AS, Pérez-Rojas J, Martínez-I-Cózar V, Garrigós-Almerich E, Hernández-Jaras J. Fibrillary glomerulonephritis: more frequent than it seems? The diagnostical importance of immunohistochemistry. Nefrologia 2024; 44:608-611. [PMID: 39097514 DOI: 10.1016/j.nefroe.2023.05.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/22/2023] [Accepted: 05/07/2023] [Indexed: 08/05/2024] Open
Affiliation(s)
- Iris Viejo-Boyano
- Department of Nephrology, La Fe University and Polytechnic Hospital, Valencia, Spain.
| | - Gema Moreno-Abenza
- Department of of Anatomical Pathology, La Fe University and Polytechnic Hospital, Valencia, Spain.
| | | | - Judith Pérez-Rojas
- Department of of Anatomical Pathology, La Fe University and Polytechnic Hospital, Valencia, Spain.
| | - Vicent Martínez-I-Cózar
- Department of of Anatomical Pathology, La Fe University and Polytechnic Hospital, Valencia, Spain.
| | | | - Julio Hernández-Jaras
- Department of Nephrology, La Fe University and Polytechnic Hospital, Valencia, Spain.
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3
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Attieh RM, Yang Y, Rosenstock JL. Updates on the Diagnosis and Management of Fibrillary Glomerulonephritis. ADVANCES IN KIDNEY DISEASE AND HEALTH 2024; 31:374-383. [PMID: 39084762 DOI: 10.1053/j.akdh.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/15/2024] [Accepted: 03/25/2024] [Indexed: 08/02/2024]
Abstract
Fibrillary glomerulonephritis (FGN) is a rare kidney disease typically affecting individuals in middle age, frequently presenting with advanced renal failure, proteinuria, and hypertension. FGN can be associated with autoimmune diseases, hepatitis C infection, and malignancies. Its exact pathogenesis remains elusive, and the exact role of DnaJ homolog subfamily B member 9 is yet to be determined. On renal biopsy, FGN exhibits distinctive Congo-red-negative, nonbranching fibrils, approximately 20 nm in diameter. DnaJ homolog subfamily B member 9 immunohistochemical staining has become a gold standard for diagnosis. Atypical variants exist, including congophilic, monotypic, and crescentic FGN, highlighting the disease's heterogeneity. Treatment with immunosuppression, including rituximab, has shown variable success, with no standard therapy established. FGN often leads to end-stage kidney disease, with a median progression time of 2-4 years postdiagnosis. Kidney transplantation is a viable option for FGN-related end-stage kidney disease, but recurrence in transplanted kidneys is not rare.
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Affiliation(s)
- Rose Mary Attieh
- Division of Kidney Diseases and Hypertension, Glomerular Center at Northwell Health, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York
| | - Yihe Yang
- Department of Pathology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York
| | - Jordan L Rosenstock
- Division of Nephrology, Lenox Hill Hospital, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, NY.
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4
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Lafargue MC, Cohen C. [Latest updates on immunotactoid glomerulopathy and fibrillary glomerulonephritis]. Bull Cancer 2024; 111:741-747. [PMID: 36803980 DOI: 10.1016/j.bulcan.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 12/10/2022] [Accepted: 12/18/2022] [Indexed: 02/17/2023]
Abstract
Various hematologic malignancies can lead to renal complications. The most common of these hemopathies to affect the kidney is multiple myeloma, however an increasing number of kidney diseases are associated with other monoclonal gammopathies. It is recognized that clones in small abundance can be responsible for severe organ damage, thus the concept of monoclonal gammopathy of renal significance (MGRS) has emerged. Although the hemopathy in these patients is more consistent with monoclonal gammopathy of undetermined significance (MGUS) than with multiple myeloma, the diagnosis of a renal complication changes the therapeutic management. Preservation and restoration of renal function is possible with treatment targeting the responsible clone. In this article, we take as an example immunotactoid and fibrillary glomerulopathies, two distinct entities with different etiologies and consequently different management. Immunotactoid glomerulopathy is most often associated with monoclonal gammopathy or chronic lymphocytic leukemia, the deposits on renal biopsy are monotypic, and treatment is therefore based on clone targeting. Fibrillary glomerulonephritis, on the other hand, is caused by autoimmune diseases or solid cancers. Deposits on renal biopsy are in the vast majority polyclonal. There is a specific immunohistochemical marker, DNAJB9, and treatment is less well established.
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Affiliation(s)
- Marie-Camille Lafargue
- Université Paris Cité, Assistance Publique-hôpitaux de Paris, hôpital Necker, service de néphrologie, 149, rue de Sèvres, 75015 Paris, France
| | - Camille Cohen
- Inserm U1151 « mechanisms and therapeutic strategies of chronic kidney diseases », hôpital Necker, université Paris Cité, service de néphrologie et transplantation rénale, hôpital Necker, Assistance Publique-hôpitaux de Paris, Paris, France.
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5
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Dumas De La Roque C, Brocheriou I, Mirouse A, Cacoub P, Le Joncour A. [Fibrillary glomerulonephritis]. Rev Med Interne 2024:S0248-8663(24)00567-8. [PMID: 38755072 DOI: 10.1016/j.revmed.2024.05.005] [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: 12/11/2023] [Revised: 04/15/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024]
Abstract
Fibrillary glomerulonephritis (FGN) is a glomerular disease described since 1977, with a prevalence in renal biopsies of less than 1%. It presents as renal failure, proteinuria, haematuria and hypertension in middle-aged adults. It is defined histologically, using light microscopy, which reveals organised deposits of fibrils measuring around 20nm, which are negative for Congo red staining. Electron microscopy, the first gold standard for diagnosis, has now been superseded by immunohistochemistry using the anti-DNAJB9 antibody. The discovery of this molecule has revolutionised the diagnosis of GNF, thanks to its excellent sensitivity and specificity (98% and 99% respectively). The association of GNF with hepatitis C virus, autoimmune diseases, neoplasia or haemopathy is debated. Renal prognosis is guarded, with 50% of patients progressing to end-stage renal failure within 2 to 4years of diagnosis. In the absence of randomised controlled trials, the recommended treatment is based on nephroprotective measures, corticosteroid therapy and possibly a second-line immunosuppressant such as rituximab. After renal transplantation, recovery or recurrence is possible. The pathophysiology of the disease is still poorly understood, and further studies are needed.
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Affiliation(s)
- C Dumas De La Roque
- Département de médecine interne et immunologie clinique, hôpital de la Pitié-Salpêtrière, 75013 Paris, France; Centre de référence maladies auto-immunes systémiques rares, Paris, France; Sorbonne université, Paris, France
| | - I Brocheriou
- Service d'anatomie pathologique, hôpital de la Pitié-Salpêtrière, 75013 Paris, France; Sorbonne université, Paris, France
| | - A Mirouse
- Département de médecine interne et immunologie clinique, hôpital de la Pitié-Salpêtrière, 75013 Paris, France; Centre de référence maladies auto-immunes systémiques rares, Paris, France; Sorbonne université, Paris, France
| | - P Cacoub
- Département de médecine interne et immunologie clinique, hôpital de la Pitié-Salpêtrière, 75013 Paris, France; Centre de référence maladies auto-immunes systémiques rares, Paris, France; Sorbonne université, Paris, France
| | - A Le Joncour
- Département de médecine interne et immunologie clinique, hôpital de la Pitié-Salpêtrière, 75013 Paris, France; Centre de référence maladies auto-immunes systémiques rares, Paris, France; Sorbonne université, Paris, France.
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Sabanis N, Liaveri P, Geladari V, Liapis G, Moustakas G. DNAJB9 Fibrillary Glomerulonephritis With Membranous-Like Pattern: A Case-Based Literature Review. Cureus 2023; 15:e47862. [PMID: 37899889 PMCID: PMC10612487 DOI: 10.7759/cureus.47862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2023] [Indexed: 10/31/2023] Open
Abstract
Fibrillary glomerulonephritis (FGN) is a rare immune-mediated glomerular disease traditionally characterized by the presence of amyloid-like, randomly aligned, fibrillary deposits in the capillary wall, measuring approximately 20 nm in diameter and composed of polyclonal IgG. FGN is usually a primary disease with no pathognomonic clinical or laboratory findings. More than that, on light microscopic evaluation, it can receive various histological patterns, rendering its diagnosis indistinguishable. However, the identification by immunohistochemistry of a novel biomarker, DNA-J heat-shock protein family member B9 (DNAJB9), has created a new era in FGN diagnosis even in the absence of electron microscopy. Typically, most patients manifest various degrees of renal insufficiency, hypertension, microscopic hematuria, proteinuria, and occasionally frank nephrotic syndrome. The prognosis is usually severe and progression to end-stage kidney disease (ESKD) is the rule, given that no specific treatment is available until now, despite the fact that in small studies rituximab-based therapy seems to alleviate the severity and improve the disease progression. Herein, we report the case of a 63-year-old Caucasian man presenting with uncontrolled hypertension, headache, shortness of breath, and lower limb edema. Diagnostic evaluation revealed mild deterioration of kidney function, nephrotic range proteinuria, and faint IgGκ monoclonal bands in serum and urine immunofixation. After negative meticulous investigation for secondary nephrotic syndrome causes, the patient underwent a kidney biopsy. Biopsy sample showed two glomeruli with mesangial expansion and thickened glomerular basement membrane (GBM) on light microscopy, a pattern masquerading as membranous nephropathy stage III-IV, while IgG and C3 were 1-2+ on GBM and mesangium in immunofluorescence. Thickened GBM with fibrils on electron microscopy were found, while DNAJB9 in immunohistochemistry was positive, confirming FGN. Once diagnosis of FGN was made, a combination of steroids with rituximab was initiated while the patient was receiving the standard anti-hypertensive therapy, simultaneously with a sodium-glucose cotransporter-2 (SGLT2) inhibitor. The 12-month follow-up showed approximately 85% decrease in proteinuria alongside stabilization of kidney function and blood pressure normalization. Hence, in this article, we aim to highlight that DNAJB9-associated FGN may mimic membranous glomerulopathy stage III-IV on light microscopy, especially when a small kidney sample with extensive involvement by fibrils of GBM is examined. Moreover, we underscore the fact that ultramicroscopic examination is of crucial importance in the differential diagnosis of glomerular deposition diseases and that DNAJB9 identification on immunohistochemistry consists of a revolutionary and robust biomarker in FGN diagnosis.
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Affiliation(s)
- Nikolaos Sabanis
- Department of Nephrology, General Hospital of Trikala, Trikala, GRC
| | - Paraskevi Liaveri
- Department of Nephrology, General Hospital of Athens "Georgios Gennimatas", Athens, GRC
| | - Virginia Geladari
- Department of Internal Medicine, General Hospital of Trikala, Trikala, GRC
| | - George Liapis
- Department of Pathology, National and Kapodistrian University of Athens, Athens, GRC
| | - George Moustakas
- Department of Nephrology, General Hospital of Athens "Georgios Gennimatas", Athens, GRC
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Javaugue V, Said SM, Bu L, Bridoux F, François A, Goujon JM, Fayad R, Ross D, Sastry A, Fervenza FC, Leung N, Nasr SH. Prognostic Value of Diffuse Crescentic Lesions in Fibrillary Glomerulonephritis. Am J Kidney Dis 2023; 81:368-370. [PMID: 36228825 DOI: 10.1053/j.ajkd.2022.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/11/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Vincent Javaugue
- Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Department of Nephrology, Centre Hospitalier Universitaire, Université de Poitiers, Poitiers, France.
| | - Samar M Said
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Lihong Bu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Frank Bridoux
- Department of Nephrology, Centre Hospitalier Universitaire, Université de Poitiers, Poitiers, France
| | - Arnaud François
- Department of Pathology, Centre Hospitalier Universitaire, Rouen, France
| | - Jean-Michel Goujon
- Department of Pathology and Ultrastructural Pathology, Centre Hospitalier Universitaire, Poitiers, France
| | - Ramy Fayad
- Nephrology Consultants of Northwest Ohio, Toledo, Ohio
| | - Dennis Ross
- Kansas Nephrology Physicians, Wichita, Kansas
| | - Ashok Sastry
- Department of Internal Medicine, Florida State University School of Medicine, Sarasota, Florida
| | - Fernando C Fervenza
- Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Nelson Leung
- Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Hematology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Samih H Nasr
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
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8
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Jagadish A, Vedantam V, Vedantam N, Magacha HM. Fibrillary Glomerulonephritis in a Patient With Vulvar Squamous Cell Carcinoma. Cureus 2023; 15:e35068. [PMID: 36942185 PMCID: PMC10024594 DOI: 10.7759/cureus.35068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 02/18/2023] Open
Abstract
Fibrillary glomerulonephritis is a rare condition characterized by glomerular accumulation of non-branching fibrils, leading to hematuria, proteinuria, and hypertension. It is often associated with malignancy but has no known cause. A 66-year-old Caucasian female with a history of vulvar squamous cell carcinoma presented with one month of painless hematuria in the setting of new-onset progressive renal dysfunction and nephrotic range proteinuria. Comprehensive evaluation, including renal biopsy with staining for DnaJ heat shock protein family member B9 (DNAJB9), provided a definitive diagnosis of fibrillary glomerulonephritis. The patient initially received rituximab and prednisone therapy. Unfortunately, her renal function continued to decline over the next month, requiring re-hospitalization with initiation of hemodialysis. To our knowledge, this is the first case describing an association between vulvar squamous cell carcinoma and fibrillary glomerulonephritis.
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Affiliation(s)
- Ashwin Jagadish
- Internal Medicine, East Tennessee State University Quillen College of Medicine, Johnson City, USA
| | - Venkata Vedantam
- Internal Medicine, East Tennessee State University Quillen College of Medicine, Johnson City, USA
| | - Neethu Vedantam
- Infectious Diseases, East Tennessee State University Quillen College of Medicine, Johnson City, USA
| | - Hezborn M Magacha
- General Practice, East Tennessee State University College of Public Health, Johnson City, USA
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Da Y, Goh GH, Lau T, Chng WJ, Soekojo CY. Fibrillary Glomerulonephritis and Monoclonal Gammopathy: Potential Diagnostic Challenges. Front Oncol 2022; 12:880923. [PMID: 35692803 PMCID: PMC9174543 DOI: 10.3389/fonc.2022.880923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
Fibrillary glomerulonephritis (FGN) is a rare glomerular disease featured by the randomly arranged 12- to 24-nm fibrils under electron microscopy (EM). Up to 10% of FGN patients have monoclonal gammopathy. However, distinguishing between FGN as monoclonal gammopathy of renal significance (MGRS) and FGN from other causes with incidental monoclonal gammopathy of undetermined significance (MGUS) can be challenging, as the current way of demonstrating monoclonality is flawed due to (1) the suboptimal sensitivity of kappa staining by immunofluorescence in frozen tissue (IF-F) as compared to pronase-digested paraffin sections (IF-P), causing incorrect labeling of light chain restriction; (2) the unavailability of immunoglobulin G (IgG) subtyping in some centers; and (3) the unavailability of tests demonstrating the monoclonality of highly variable VH or VL domains in immunoglobulin structures in clinical use. The discovery of DnaJ homolog subfamily B member 9 (DNAJB9) allows diagnosis for FGN with less reliance on EM, and the summary of recent studies revealed that genuine MGRS is extremely rare among FGN. Further research integrating IF-P, IgG subtyping, VH or VL domain monoclonality confirmation, and DNAJB9 as diagnostic modalities, with corresponding clinical data including treatment response and prognosis, is required for a better understanding of this subject.
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Affiliation(s)
- Yi Da
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore, Singapore
| | - Giap Hean Goh
- Department of Pathology, National University Hospital, Singapore, Singapore
| | - Titus Lau
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore, Singapore
| | - Wee Joo Chng
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, Singapore
| | - Cinnie Yentia Soekojo
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, Singapore
- *Correspondence: Cinnie Yentia Soekojo,
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Sy-Go JPT, Herrmann SM, Seshan SV. Monoclonal Gammopathy-Related Kidney Diseases. Adv Chronic Kidney Dis 2022; 29:86-102.e1. [PMID: 35817530 DOI: 10.1053/j.ackd.2022.01.004] [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: 07/14/2021] [Revised: 12/09/2021] [Accepted: 01/18/2022] [Indexed: 11/11/2022]
Abstract
Monoclonal gammopathies occur secondary to a broad range of clonal B lymphocyte or plasma cell disorders, producing either whole or truncated monoclonal immunoglobulins. The kidneys are often affected by these monoclonal proteins, and, although not mutually exclusive, can involve the glomeruli, tubules, interstitium, and vasculature. The nephrotoxic potential of these monoclonal proteins is dependent on a variety of physicochemical characteristics that are responsible for the diverse clinicopathologic manifestations, including glomerular diseases with organized deposits, glomerular diseases with granular deposits, and other lesions, such as C3 glomerulopathy and thrombotic microangiopathy with unique pathophysiologic features. The diseases that involve primarily the tubulointerstitial and vascular compartments are light chain cast nephropathy, light chain proximal tubulopathy, crystal-storing histiocytosis, and crystalglobulin-induced nephropathy with distinct acute and chronic clinicopathologic features. The diagnosis of a monoclonal gammopathy-related kidney disease is established by identification of an underlying active or more commonly, low-grade hematologic malignancy, serologic evidence of a monoclonal gammopathy when detectable, and most importantly, monoclonal protein-induced pathologic lesions seen in a kidney biopsy, confirming the association with the monoclonal protein. Establishing a diagnosis may be challenging at times, particularly in the absence of an overt hematologic malignancy, with or without monoclonal gammopathy, such as proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Overall, the treatment is directed against the underlying hematologic disorder and the potential source of the monoclonal protein.
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Affiliation(s)
| | - Sandra M Herrmann
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN.
| | - Surya V Seshan
- Department of Anatomic Pathology and Clinical Pathology, Weil Cornell Medical College, New York, NY
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Andeen NK, Avasare RS. DNA J homolog subfamily B member 9 and other advances in fibrillary glomerulonephritis. Curr Opin Nephrol Hypertens 2021; 30:294-302. [PMID: 33767057 DOI: 10.1097/mnh.0000000000000706] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Fibrillary glomerulonephritis (FGN) involves ∼1% of native kidney biopsies and is characterized by glomerular deposition of fibrils larger than amyloid (12-24 nm diameter) composed of polyclonal immunoglobulin G (IgG). The recent discovery of DNA J homolog subfamily B member 9 (DNAJB9) in FGN glomerular deposits has contributed a specific and sensitive biomarker, informing morphologic classification and pathogenesis. This review will consider contemporary FGN incidence and genetics, pathogenesis, (lack of) paraprotein association, variants, treatment, and transplantation. RECENT FINDINGS DNAJB9 tissue assays have enabled the identification of morphologic variants and improved classification of fibrillary-like glomerular diseases. Together with paraffin immunofluorescence and IgG subclass studies, these have established that FGN is only rarely monoclonal and these patients usually do not have an monoclonal gammopathy. The discovery of DNAJB9 opens new avenues of investigation into FGN pathogenesis, especially those of the unfolded protein response. Treatment for FGN remains empiric, with some encouraging data on rituximab-based therapy. Transplantation is a good option for patients progressing to end-stage kidney disease. SUMMARY Advances building on the discovery of DNAJB9 in FGN should lead to long-term evolution in targeted treatment and outcome of this glomerular disease.
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Affiliation(s)
| | - Rupali S Avasare
- Department of Medicine, Division of Nephrology and Hypertension, Portland, Oregon, USA
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12
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Klomjit N, Alexander MP, Zand L. Fibrillary Glomerulonephritis and DnaJ Homolog Subfamily B Member 9 (DNAJB9). ACTA ACUST UNITED AC 2020; 1:1002-1013. [DOI: 10.34067/kid.0002532020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/02/2020] [Indexed: 11/27/2022]
Abstract
Fibrillary GN (FGN) is a rare glomerular disease that is diagnosed based on the presence of fibrils in glomeruli. The fibrils are typically noncongophilic, randomly oriented, and measure 12–24 nm. Traditionally, electron microscopy (EM) has been an important tool to aid in the diagnosis of FGN by identifying the fibrils and to distinguish it from other entities that could mimic FGN. However, recently DnaJ homolog subfamily B member 9 (DNAJB9) has emerged as both a specific and sensitive biomarker in patients with FGN. It allows prompt diagnosis and alleviates reliance on EM. DNAJB9 is a cochaperone of heat shock protein 70 and is involved in endoplasmic reticulum protein-folding pathways. But its role in the pathogenesis of FGN remains elusive. DNAJB9 may act as a putative antigen or alternatively it may secondarily bind to misfolded IgG in the glomeruli. These hypotheses need future studies to elucidate the role of DNAJB9 in the pathogenesis of FGN. The treatment regimen for FGN has been limited due to paucity of studies. Most patients receive combination immunosuppressive regimens. Rituximab has been studied the most in FGN and it may delay disease progression. Prognosis of FGN remains poor and 50% require dialysis within 2 years of diagnosis. Despite its poor prognosis in native kidneys, the rate of recurrence post-transplantation is low (20%) and patient as well as allograft outcomes are similar to patients without FGN.
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