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Khandelwal P, Joshi A, Mathur A, Puraswani M, Gurjar BS, Sinha A, Hari P, Faruq M, Bagga A. Variants in complement genes are uncommon in patients with anti-factor H autoantibody-associated atypical hemolytic uremic syndrome. Pediatr Nephrol 2023; 38:2659-2668. [PMID: 36622444 DOI: 10.1007/s00467-022-05862-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 01/10/2023]
Abstract
BACKGROUND Coexisting genetic variants in patients with anti-factor H (FH)-associated atypical hemolytic uremic syndrome (aHUS) have implications for therapy. We estimated the prevalence of complement genetic variants in children with anti-FH aHUS from a prospective nationwide cohort and determined if significant genetic variants impact long-term kidney outcomes. METHODS Of 436 patients in the database, 77 consecutive patients, 21 with a relapse and 9 with kidney failure and/or death were included. Targeted sequencing, using a 27-gene panel including CFH, CFI, CFB, C3, CD46, PLG, DGKE, and THBD and multiplex ligation-dependent probe amplification of CFH-CFHR region, was performed. The adverse outcome was eGFR < 30 ml/min/1.73 m2 or death. RESULTS Patients had high anti-FH titers 5670 (2177-13,545) AU/ml, relapsing course (42.1%), and adverse outcomes (19.6%). Variants, chiefly of unknown significance, were found in 7 (6.5%; 95% CI 3.1-13.2%); a pathogenic variant was found in one patient. Homozygous deletion of CFHR1 was present in 91.6% compared to 9.8% in 184 healthy controls. Plasma exchanges and immunosuppression showed a trend of improving outcomes, independent of genetic defects (HR 0.32; P = 0.070). Meta-analysis of 18 studies (384 patients) showed that the pooled prevalence of pathogenic and likely pathogenic variants was 3% (95% CI 0-8%). Of 37 total variants in the meta-analysis, 7 (18.9%) each were pathogenic and likely pathogenic; others were variants of unknown significance. CONCLUSIONS Significant variants in complement regulatory genes are rare in patients with anti-FH-associated aHUS. Irrespective of genetic defects, plasma exchanges and immunosuppression showed a statistical trend to improved outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Aditi Joshi
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Aradhana Mathur
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Mamta Puraswani
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Bahadur Singh Gurjar
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
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Puraswani M, Khandelwal P, Saini H, Saini S, Gurjar BS, Sinha A, Shende RP, Maiti TK, Singh AK, Kanga U, Ali U, Agarwal I, Anand K, Prasad N, Rajendran P, Sinha R, Vasudevan A, Saxena A, Agarwal S, Hari P, Sahu A, Rath S, Bagga A. Clinical and Immunological Profile of Anti-factor H Antibody Associated Atypical Hemolytic Uremic Syndrome: A Nationwide Database. Front Immunol 2019; 10:1282. [PMID: 31231391 PMCID: PMC6567923 DOI: 10.3389/fimmu.2019.01282] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 05/20/2019] [Indexed: 12/12/2022] Open
Abstract
Background: Atypical hemolytic uremic syndrome (aHUS), an important cause of acute kidney injury (AKI), is characterized by dysregulation of the alternative complement pathway. Autoantibodies to factor H (FH), a chief regulator of this pathway, account for a distinct subgroup. While high anti-FH titers predict relapse, they do not correlate well with disease activity and their functional characterization is required. Methods: Of 781 patients <18-year-old of aHUS in the nationwide database from 2007 to 2018, 436 (55.8%) had anti-FH antibodies. Clinical features and outcome of patients managed in the last 6-year (n = 317) were compared to before (n = 119). In plasma samples of 44 patients, levels of serial circulating FH immune complexes (CIC), free FH, soluble terminal complement complex (sC5b-9), sheep red blood cell (SRBC) lysis and epitope specificity (n = 8) were examined. Functional renal reserve, ambulatory hypertension, left ventricular hypertrophy (LVH), and proteinuria were evaluated in a subset. Results: Patients presented with markedly elevated anti-FH titers (10,633.2 ± 998.5 AU/ml). Management varied by center, comprising plasma exchange (PEX; 77.5%) and immunosuppression (73.9%). Patients managed in the last 6-year showed better renal survival at mean 28.5 ± 27.3 months (log rank P = 0.022). Mean anti-FH titers stayed 700–1,164 AU/ml during prolonged follow-up, correlating with CIC. Patients with relapse had lower free-FH during remission [Generalized estimating equations (GEE), P = 0.001]; anti-FH levels ≥1,330 AU/ml and free FH ≤440 mg/l predicted relapse (hazards ratio, HR 6.3; P = 0.018). Epitope specificity was similar during onset, remission and relapse. Antibody titer ≥8,000 AU/ml (HR 2.23; P = 0.024), time to PEX ≥14 days (HR 2.09; P = 0.071) and PEX for <14 days (HR 2.60; P = 0.017) predicted adverse renal outcomes. Combined PEX and immunosuppression improved long-term outcomes (HR 0.37; P = 0.026); maintenance therapy reduced risk of relapses (HR 0.11; P < 0.001). At 4.4±2.5 year, median renal reserve was 15.9%; severe ambulatory, masked and pre-hypertension were found in 38, 30, and 18%, respectively. Proteinuria and LVH occurred in 58 and 28% patients, respectively. Conclusion: Prompt recognition and therapy with PEX and immunosuppression, is associated with satisfactory outcomes. Free-FH predicts early relapses in patients with high anti-FH titers. A significant proportion of impaired functional reserve, ambulatory hypertension, proteinuria and LVH highlight the need for vigilant long-term follow-up.
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Affiliation(s)
- Mamta Puraswani
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Himanshi Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Savita Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Bahadur Singh Gurjar
- Immuno Biology Laboratory II, National Institute of Immunology, New Delhi, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | | | | | | | - Uma Kanga
- Department of Transplant Immunology and Immunogenetics, All India Institute of Medical Sciences, New Delhi, India
| | - Uma Ali
- Department of Pediatrics, BJ Wadia Hospital for Children, Mumbai, India
| | - Indira Agarwal
- Department of Pediatrics, Christian Medical College, Vellore, India
| | - Kanav Anand
- Division of Pediatric Nephrology, Sir Ganga Ram Hospital, New Delhi, India
| | - Narayan Prasad
- Department of Nephrology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India
| | - Padmaraj Rajendran
- Department of Pediatric Nephrology, Institute of Child Health and Hospital for Children, Madras Medical College, Chennai, India
| | - Rajiv Sinha
- Department of Pediatrics, Institute of Child Health, Kolkata, India
| | - Anil Vasudevan
- Department of Pediatric Nephrology, St. Johns Medical College and Hospital, Bengaluru, India
| | - Anita Saxena
- Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India
| | - Sanjay Agarwal
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Arvind Sahu
- National Centre for Cell Science, Pune, India
| | - Satyajit Rath
- National Centre for Cell Science, Pune, India.,Translational Health Science and Technology Institute, Faridabad, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
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Gurjar BS, Manikanta Sriharsha T, Bhasym A, Prabhu S, Puraswani M, Khandelwal P, Saini H, Saini S, Verma AK, Chatterjee P, Guchhait P, Bal V, George A, Rath S, Sahu A, Sharma A, Hari P, Sinha A, Bagga A. Characterization of genetic predisposition and autoantibody profile in atypical haemolytic-uraemic syndrome. Immunology 2018; 154:663-672. [PMID: 29485195 PMCID: PMC6050217 DOI: 10.1111/imm.12916] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 12/25/2022] Open
Abstract
We previously reported that Indian paediatric patients with atypical haemolytic-uraemic syndrome (aHUS) showed high frequencies of anti-complement factor H (FH) autoantibodies that are correlated with homozygous deletion of the genes for FH-related proteins 1 and 3 (FHR1 and FHR3) (FHR1/3-/- ). We now report that Indian paediatric aHUS patients without anti-FH autoantibodies also showed modestly higher frequencies of the FHR1/3-/- genotype. Further, when we characterized epitope specificities and binding avidities of anti-FH autoantibodies in aHUS patients, most anti-FH autoantibodies were directed towards the FH cell-surface anchoring polyanionic binding site-containing C-terminal short conservative regions (SCRs) 17-20 with higher binding avidities than for native FH. FH SCR17-20-binding anti-FH autoantibodies also bound the other cell-surface anchoring polyanionic binding site-containing region FH SCR5-8, at lower binding avidities. Anti-FH autoantibody avidities correlated with antibody titres. These anti-FH autoantibody characteristics did not differ between aHUS patients with or without the FHR1/3-/- genotype. Our data suggest a complex matrix of interactions between FHR1-FHR3 deletion, immunomodulation and anti-FH autoantibodies in the aetiopathogenesis of aHUS.
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Affiliation(s)
| | | | - Angika Bhasym
- Regional Centre for BiotechnologyFaridabadIndia
- Department of BiotechnologyManipal Academy of Higher EducationManipalIndia
| | - Savit Prabhu
- Paediatric Biology CentreTranslational Health Science and Technology InstituteFaridabadIndia
| | - Mamta Puraswani
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Priyanka Khandelwal
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Himanshi Saini
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Savita Saini
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | | | | | | | - Vineeta Bal
- National Institute of ImmunologyNew DelhiIndia
- Paediatric Biology CentreTranslational Health Science and Technology InstituteFaridabadIndia
| | - Anna George
- National Institute of ImmunologyNew DelhiIndia
| | - Satyajit Rath
- National Institute of ImmunologyNew DelhiIndia
- Paediatric Biology CentreTranslational Health Science and Technology InstituteFaridabadIndia
- Agharkar Research InstitutePuneIndia
| | - Arvind Sahu
- National Centre for Cell ScienceS. P. Pune University CampusPuneIndia
| | - Amita Sharma
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Pankaj Hari
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Aditi Sinha
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Arvind Bagga
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
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Thergaonkar RW, Narang A, Gurjar BS, Tiwari P, Puraswani M, Saini H, Sinha A, Varma B, Mukerji M, Hari P, Bagga A. Targeted exome sequencing in anti-factor H antibody negative HUS reveals multiple variations. Clin Exp Nephrol 2017; 22:653-660. [PMID: 28939980 DOI: 10.1007/s10157-017-1478-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/03/2017] [Indexed: 02/01/2023]
Abstract
BACKGROUND Genetic susceptibility to atypical hemolytic uremic syndrome (aHUS) may lie within genes regulating or activating the alternate complement and related pathways converging on endothelial cell activation. METHODS We tested 32 Indian patients of aHUS negative for antibodies to complement factor H for genetic variations in a panel of 15 genes, i.e., CFH, CFHR1-5, CFI, CFB, C3, CD46, MASP2, DGKE, ADAMTS13, THBD and PLG using next-generation DNA sequencing and for copy number variation in CFHR1-3. RESULTS Despite absence of a public database of exome variations in the Indian population and limited functional studies, we could establish a genetic diagnosis in 6 (18.8%) patients using a stringent scheme of prioritization. One patient carried a likely pathogenic variation. The number of patients carrying possibly pathogenic variation was as follows: 1 variation: 5 patients, 2 variations: 9 patients, 3 variations: 5 patients, 4 variations: 9 patients, 5 variations: 2 patients and 6 variations: 2 patients. Homozygous deletion of CFHR1-3 was present in five patients; none of these carried a diagnostic genetic variation. Patients with or without diagnostic variation did not differ significantly in terms of enrichment of genetic variations that were rare/novel or predicted deleterious, or for possible environmental triggers. CONCLUSION We conclude that genetic testing for multiple genes in patients with aHUS negative for anti-FH antibodies reveals multiple candidate variations that require prioritization. Population data on variation frequency of the Indian population and supportive functional studies are likely to improve diagnostic yield.
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Affiliation(s)
- R W Thergaonkar
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Ankita Narang
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | | | - Pradeep Tiwari
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Mamta Puraswani
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Himanshi Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Binuja Varma
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Mitali Mukerji
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
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Sinha A, Gulati A, Saini S, Blanc C, Gupta A, Gurjar BS, Saini H, Kotresh ST, Ali U, Bhatia D, Ohri A, Kumar M, Agarwal I, Gulati S, Anand K, Vijayakumar M, Sinha R, Sethi S, Salmona M, George A, Bal V, Singh G, Dinda AK, Hari P, Rath S, Dragon-Durey MA, Bagga A. Prompt plasma exchanges and immunosuppressive treatment improves the outcomes of anti-factor H autoantibody-associated hemolytic uremic syndrome in children. Kidney Int 2013; 85:1151-60. [PMID: 24088957 DOI: 10.1038/ki.2013.373] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 07/22/2013] [Accepted: 08/01/2013] [Indexed: 02/06/2023]
Abstract
Antibodies to complement factor H are an uncommon cause of hemolytic uremic syndrome (HUS). Information on clinical features and outcomes in children is limited. In order to explore this we studied a multicenter cohort of 138 Indian children with anti-complement factor H antibody associated HUS, constituting 56% of patients with HUS. Antibody titers were high (mean 7054 AU/ml) and correlated inversely with levels of complement C3, but not complement factor H. Homozygous deletion of the CFHR1 gene was found in 60 of 68 patients. Therapies included dialysis in 119 children, 105 receiving plasma exchanges and 26 intravenous immunoglobulin. Induction immunosuppression consisted of 87 children receiving prednisolone with or without intravenous cyclophosphamide or rituximab. Antibody titers fell significantly following plasma exchanges and increased during relapses. Adverse outcome (stage 4-5 CKD or death) was seen in 36 at 3 months and 41 by last follow up, with relapse in 14 of 122 available children. Significant independent risk factors for adverse outcome were an antibody titer over 8000 AU/ml, low C3 and delay in plasma exchange. Combined plasma exchanges and induction immunosuppression resulted in significantly improved renal survival: one adverse outcome prevented for every 2.6 patients treated. Maintenance immunosuppressive therapy, of prednisolone with either mycophenolate mofetil or azathioprine, significantly reduced the risk of relapses. Thus, prompt use of immunosuppressive agents and plasma exchanges are useful for improving outcomes in pediatric patients with anti-complement factor H-associated HUS.
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Affiliation(s)
- Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Ashima Gulati
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Savita Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Caroline Blanc
- Laboratoire d'Immunologie, Hôpital Européen Georges Pompidou, INSERM UMRS 872, team 13 and Paris Descartes University, Paris, France
| | - Aarti Gupta
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | | | - Himanshi Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Shambhuprasad T Kotresh
- Laboratoire d'Immunologie, Hôpital Européen Georges Pompidou, INSERM UMRS 872, team 13 and Paris Descartes University, Paris, France
| | - Uma Ali
- Department of Pediatrics, BJ Wadia Hospital for Children, Mumbai, India
| | - Divya Bhatia
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Alpana Ohri
- Department of Pediatrics, BJ Wadia Hospital for Children, Mumbai, India
| | | | - Indira Agarwal
- Department of Pediatrics, Christian Medical College, Vellore, India
| | - Sanjeev Gulati
- Department of Nephrology, Fortis Hospitals, New Delhi, India
| | - Kanav Anand
- Division of Pediatric Nephrology, Sir Ganga Ram Hospital, New Delhi, India
| | - M Vijayakumar
- Department of Pediatric Nephrology, Mehta Children's Hospital, Chennai, India
| | | | - Sidharth Sethi
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Maud Salmona
- Laboratoire d'Immunologie, Hôpital Européen Georges Pompidou, INSERM UMRS 872, team 13 and Paris Descartes University, Paris, France
| | - Anna George
- National Institute of Immunology, New Delhi, India
| | - Vineeta Bal
- National Institute of Immunology, New Delhi, India
| | - Geetika Singh
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Amit K Dinda
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | | | - Marie-Agnes Dragon-Durey
- Laboratoire d'Immunologie, Hôpital Européen Georges Pompidou, INSERM UMRS 872, team 13 and Paris Descartes University, Paris, France
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
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