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Khandelwal P, Nambiar S, Saini R, Saini S, Coshic P, Sinha A, Hari P, Palanichamy JK, Bagga A. Anti-factor B antibodies in atypical hemolytic uremic syndrome. Pediatr Nephrol 2024; 39:1909-1916. [PMID: 38252289 DOI: 10.1007/s00467-024-06284-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/20/2023] [Accepted: 12/23/2023] [Indexed: 01/23/2024]
Abstract
BACKGROUND The etiology of atypical hemolytic uremic syndrome (aHUS) is unknown in 30-40% of patients. Anti-factor B (FB) antibodies are reported in C3 glomerulopathy (C3G) and immune-complex membranoproliferative glomerulonephritis (IC-MPGN), though not in aHUS. METHODS We screened patients < 18-year-old from cohorts of aHUS and C3G/idiopathic IC-MPGN. Anti-FB IgG antibodies were measured by ELISA and confirmed by Western blot. Normative levels were based on antibody levels in 103 healthy blood donors. RESULTS Prevalence of anti-FB antibodies was 9.7% (95% CI 6.1-14.5%; n = 21) in 216 patients with aHUS, including 11.5% (95% CI 6.4-18.5%; n = 14) in anti-FH associated aHUS and 11.8% (95% CI 4.4-23.9%; n = 6) in patients without a definitive genetic or autoimmune etiology. Patients with significant genetic variants did not show anti-FB antibodies. In patients with concomitant anti-FB and anti-FH antibodies, median anti-FH titers were higher (11,312 AU/mL vs. 4920 AU/mL; P = 0.04). Anti-FB antibody titer correlated with disease severity (hemoglobin and platelets; P < 0.05), declined following plasma exchange and increased during relapse. While 4/64 patients with C3G (6.3%) and 1/17 with IC-MPGN showed anti-FB antibodies, titers were higher in aHUS (544.8 AU/mL vs. 1028.8 AU/mL; P = 0.003). CONCLUSION Anti-FB antibodies are present in 6-10% of patients with aHUS and C3G/IC-MPGN, with higher titers in the former. The diagnostic and therapeutic implication of anti-FB antibodies in aHUS needs confirmation and further studies. The study shows propensity for autoantibody generation and co-existence of multiple risk factors for aHUS in Indian children.
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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, New Delhi, India
| | - Shreesha Nambiar
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Rahul Saini
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Savita Saini
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Poonam Coshic
- Department of Transfusion Medicine and Blood Bank, All India Institute of Medical Sciences, New Delhi, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | | | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, New Delhi, India.
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Li Q, Kong X, Tian M, Wang J, Yang Z, Yu L, Liu S, Wang C, Wang X, Sun S. Clinical features of children with anti-CFH autoantibody-associated hemolytic uremic syndrome: a report of 8 cases. Ren Fail 2022; 44:1061-1069. [PMID: 35730179 PMCID: PMC9225730 DOI: 10.1080/0886022x.2022.2089167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Objective To explore the clinical characteristics, treatment protocol and prognosis of children with anti-complement factor H (CFH) autoantibody (Ab)-associated hemolytic uremic syndrome (HUS). Methods Clinical data of 8 patients with anti-CFH Ab-associated HUS who were admitted to Shandong Provincial Hospital from January 2011 to December 2020 were collected retrospectively. Results The age at disease onset ranged between 5.83 and 13.5 years, with a male: female ratio of 1.67:1. The time of onset was distributed from May to June and November to December. Digestive and upper respiratory tract infections were common prodromal infections. Positivity for anti-CFH Ab and reduced C3 levels were observed among all patients. Heterozygous mutation of the CHFR5 gene (c.669del A) and homozygous loss of the CFHR1 gene [loss2(EXON:2-6)] were found in two patients. All patients received early treatment with plasma exchange and corticosteroid therapy. Six patients were given immunosuppressive agents (cyclophosphamide and/or mycophenolate mofetil) for persistent proteinuria. The follow-up period was 12–114 months. Four of 8 patients achieved complete remission, 3 achieved partial remission, and 1 died. Relapse occurred in two patients. Conclusion Children with anti-CFH Ab-associated HUS were mainly school-aged and predominantly male, with onset times of summer and winter. Digestive and upper respiratory tract infections were common prodromal infections. Plasma exchange combined with methylprednisolone pulse therapy in the acute phase and cyclophosphamide or mycophenolate mofetil treatment for maintenance can be utilized in children with anti-CFH Ab-associated HUS if eculizumab is not available.
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Affiliation(s)
- Qian Li
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Xinxin Kong
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Minle Tian
- School of Basic Medical Sciences, Shandong First Medical University, Taian, Shandong, China
| | - Jing Wang
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Zhenle Yang
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Lichun Yu
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Suwen Liu
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Cong Wang
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Xiaoyuan Wang
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
| | - Shuzhen Sun
- Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, P. R. China.,Department of Pediatric Nephrology and Rheumatism and Immunology, Shandong Provincial Hospital, Affiliated to Shandong First Medical University, Jinan, P. R. China
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Khandelwal P, Krishnasamy S, Govindarajan S, Kumar M, Marik B, Sinha A, Hari P, Bagga A. Anti-factor H antibody associated hemolytic uremic syndrome following SARS-CoV-2 infection. Pediatr Nephrol 2022; 37:2151-2156. [PMID: 35089377 PMCID: PMC8796738 DOI: 10.1007/s00467-021-05390-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/20/2021] [Accepted: 11/15/2021] [Indexed: 01/29/2023]
Abstract
BACKGROUND The pathogenesis of autoantibody generation in anti-factor H (FH) antibody associated atypical hemolytic uremic syndrome (aHUS) is unknown and is perhaps triggered by an infectious or environmental agent. We observed an unusual increase of patients with anti-FH antibody associated aHUS coinciding with the second pandemic wave in New Delhi and suspected that SARS-CoV-2 infection might be a potential trigger. METHODS We screened for SARS-CoV-2 infection using reverse transcriptase polymerase chain reaction (RT-PCR) and serology in 13 consecutive patients with anti-FH antibody associated aHUS during the past year in New Delhi. RESULTS We report 5 patients, 4-13 years old, who presented with a febrile illness without respiratory symptoms during the second pandemic wave. Of these, 3 patients presented with a relapse 25-85 months following the initial episode of aHUS. SARS-CoV-2 was detected by RT-PCR in 1 patient and by serology in 4 patients (median titer 47.1 cut-off index). Patients had high titers of anti-FH antibodies (median 2,300 AU/ml). Genetic studies, done in 3 of the 5 patients, showed homozygous CFHR1 deletion without other significant genetic abnormalities. Specific management comprised plasma exchanges and oral prednisolone, combined with either cyclophosphamide or mycophenolate mofetil. At median follow-up of 3.3 months, the estimated glomerular filtration rate in 4 patients ranged from 62 to 110 ml/min/1.73 m2; one patient was dialysis-dependent. CONCLUSION Increased vigilance is required during the pandemic, especially in patients with anti-FH associated aHUS, who might relapse despite quiescent disease for a prolonged period. 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
| | - Sudarsan Krishnasamy
- 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
| | - Srinivasavaradan Govindarajan
- 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
| | - Manish Kumar
- Department of Pediatrics, Chacha Nehru Bal Chikitsalaya, New Delhi, India
| | - Binata Marik
- 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
| | - 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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Yılmaz N, Yüksel S. Hemolytic Uremic Syndrome Associated with Norovirus Gastroenteritis: Case Report and Literature Review. Nephron Clin Pract 2022; 146:489-493. [PMID: 35313310 DOI: 10.1159/000522497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/05/2022] [Indexed: 11/19/2022] Open
Abstract
A previously healthy 3-year-old girl was admitted with fever, nonbloody diarrhea, vomiting for 3 days, and oliguria. Physical examination showed fatigue, pale appearance, hypertension, and mild periorbital edema. Laboratory examinations revealed anemia, thrombocytopenia, acute kidney injury, high LDH, and low haptoglobin levels. Urinalysis showed proteinuria and hematuria. Schistocytes and helmet cells were detected in the peripheral blood smear. There were no electrolyte imbalance and hypocomplementemia. Direct Coombs and viral panel were negative. Blood, urine, throat, and stool cultures were negative. Norovirus GII was positive in stool PCR, while other diarrheal agents were negative. The patient was diagnosed with norovirus gastroenteritis-induced hemolytic uremic syndrome (HUS). Furosemide was started for oliguria and hypertension, and blood pressure was controlled with oral nifedipine. On the 12th day of hospitalization, he was discharged with fully recover. To date, norovirus-associated HUS has been reported in 5 cases. Two of these are adult cases and the other three and our case are pediatric patients. In this case report and literature review, we observed that norovirus can cause HUS, especially in children, with a milder course than other types of HUS. The reason why it is more complicated in adult cases may be the presence of an additional underlying kidney disease. Since it was detected coincidentally in 1 case in the literature, it may be useful to screen for mutations in the complement pathway that may cause aHUS, if possible, in diarrhea-associated HUS caused by norovirus agents, but it was not present in our case.
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Affiliation(s)
- Neslihan Yılmaz
- Department of Pediatric Nephrology, Pamukkale University School of Medicine, Denizli, Turkey,
| | - Selçuk Yüksel
- Department of Pediatric Rheumatology and Pediatric Nephrology, Pamukkale University School of Medicine, Denizli, Turkey
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Anti-Factor H Antibodies in Egyptian Children with Hemolytic Uremic Syndrome. Int J Nephrol 2021; 2021:6904858. [PMID: 34840826 PMCID: PMC8616678 DOI: 10.1155/2021/6904858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/23/2021] [Accepted: 10/26/2021] [Indexed: 12/22/2022] Open
Abstract
Background Atypical hemolytic uremic syndrome (aHUS) is an important cause of acute kidney injury in children. It is primarily caused by dysregulation of the complement alternative pathway due to genetic mutations, mainly in complement factor H genes, or due to anti-factor H autoantibodies (anti-FH), leading to uncontrolled overactivation of the complement system. Early diagnosis and treatment of autoimmune HUS (AI-HUS) is essential and leads to a favorable outcome. Methods Fifty pediatric HUS patients and 50 age- and sex-matched controls were included in the study. Patients were subjected to full history taking, clinical examination, and laboratory testing. All candidates were subjected to an assessment of anti-FH in serum by a homemade enzyme-linked immunosorbent assay technique. Results A high frequency of serum anti-FH was detected in our aHUS patients. The disease onset of AI-HUS was mainly observed in March and April, with significantly higher rates in school-aged males. All patients who started immunosuppressives early together with plasmapheresis upon detection of their anti-FH had complete renal function recovery. Conclusion The high frequency of AI-HUS revealed in Egyptian HUS children in our study highlights the importance of implementing anti-FH testing in Egypt to provide early recognition for immediate proper management, including early immunosuppressive therapy, and hence improving patient outcomes.
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6
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Lung T, Sakem B, Risch L, Würzner R, Colucci G, Cerny A, Nydegger U. The complement system in liver diseases: Evidence-based approach and therapeutic options. J Transl Autoimmun 2019; 2:100017. [PMID: 32743505 PMCID: PMC7388403 DOI: 10.1016/j.jtauto.2019.100017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022] Open
Abstract
Complement is usually seen to largely originate from the liver to accomplish its tasks systemically - its return to the production site has long been underestimated. Recent progress in genomics, therapeutic effects on complement, standardised possibilities in medical laboratory tests and involvement of complosome brings the complement system with its three major functions of opsonization, cytolysis and phagocytosis back to liver biology and pathology. The LOINC™ system features 20 entries for the C3 component of complement to anticipate the application of artificial intelligence data banks algorythms of which are fed with patient-specific data connected to standard lab assays for liver function. These advancements now lead to increased vigilance by clinicians. This reassessment article will further elucidate the distribution of synthesis sites to the three germ layer-derived cell systems and the role complement now known to play in embryogenesis, senescence, allotransplantation and autoimmune disease. This establishes the liver as part of the gastro-intestinal system in connection with nosological entities never thought of, such as the microbiota-liver-brain axis. In neurological disease etiology infectious and autoimmune hepatitis play an important role in the context of causative viz reactive complement activation. The mosaic of autoimmunity, i.e. multiple combinations of the many factors producing varying clinical pictures, leads to the manifold facets of liver autoimmunity.
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Affiliation(s)
- Thomas Lung
- Labormedizinisches Zentrum Dr. Risch, Lagerstrasse 30, CH-9470, Buchs, Switzerland
| | - Benjamin Sakem
- Labormedizinisches Zentrum Dr. Risch, Waldeggstrasse 37, CH-3097, Liebefeld bei Bern, Switzerland
| | - Lorenz Risch
- Labormedizinisches Zentrum Dr. Risch, Waldeggstrasse 37, CH-3097, Liebefeld bei Bern, Switzerland
| | - Reinhard Würzner
- Medical University Innsbruck, Division of Hygiene & Medical Microbiology, Department of Hygiene, Microbiology and Public Health, Schöpfstrasse 41, A-6020, Innsbruck, Austria
| | - Giuseppe Colucci
- Clinica Luganese Moncucco, Lugano, Via Moncucco, CH-6900, Lugano, Switzerland
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Andreas Cerny
- Epatocentro Ticino, Via Soldino 5, CH-6900, Lugano, Switzerland
| | - Urs Nydegger
- Labormedizinisches Zentrum Dr. Risch, Waldeggstrasse 37, CH-3097, Liebefeld bei Bern, Switzerland
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7
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Abu Daher G, Aoun B, Jaafar F, Khafaja S, Sanjad S. Norovirus: a novel etiologic agent in hemolytic uremic syndrome in an infant. BMC Nephrol 2019; 20:247. [PMID: 31277594 PMCID: PMC6612073 DOI: 10.1186/s12882-019-1427-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/23/2019] [Indexed: 12/12/2022] Open
Abstract
Background Hemolytic uremic syndrome is a rare thrombotic microangiopathy usually seen in infants and children below the age of 5 years. It usually follows a bout of bloody diarrhea caused by Shiga toxin producing E coli and is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury. We report the first case of hemolytic uremic syndrome in an infant following Norovirus gastroenteritis. Case presentation A nine-month-old male infant, was admitted with an 8-day history of watery, non-bloody diarrhea, vomiting and decreased oral intake. Physical exam revealed normal blood pressure, pallor and generalized edema. Laboratory findings were significant for microangiopathic hemolytic anemia, thrombocytopenia and azotemia. Stool studies with Multiplex Qualitative reverse transcriptase PCR were positive for Norovirus GI/G II. His clinical course was unusually severe, complicated by oligoanuria and worsening uremia requiring peritoneal dialysis but with eventual complete recovery. Conclusions To our knowledge this is the first case of Norovirus associated HUS in an infant. Given the ubiquity of this virus as a major cause of diarrhea, together with the increased availability of Multiplex Qualitative PCR in reference laboratories, it is quite possible that we shall be seeing more such cases in the future.
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Affiliation(s)
- Ghadi Abu Daher
- Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, P.O.Box 11-0236/E29, Beirut, Lebanon
| | - Bilal Aoun
- Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, P.O.Box 11-0236/E29, Beirut, Lebanon
| | - Fatima Jaafar
- Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, P.O.Box 11-0236/E29, Beirut, Lebanon
| | - Sarah Khafaja
- Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, P.O.Box 11-0236/E29, Beirut, Lebanon
| | - Sami Sanjad
- Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, P.O.Box 11-0236/E29, Beirut, Lebanon.
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8
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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] [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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9
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Valoti E, Alberti M, Iatropoulos P, Piras R, Mele C, Breno M, Cremaschi A, Bresin E, Donadelli R, Alizzi S, Amoroso A, Benigni A, Remuzzi G, Noris M. Rare Functional Variants in Complement Genes and Anti-FH Autoantibodies-Associated aHUS. Front Immunol 2019; 10:853. [PMID: 31118930 PMCID: PMC6504697 DOI: 10.3389/fimmu.2019.00853] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/02/2019] [Indexed: 01/06/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia and renal failure. It is caused by genetic or acquired defects of the complement alternative pathway. Factor H autoantibodies (anti-FHs) have been reported in 10% of aHUS patients and are associated with the deficiency of factor H-related 1 (FHR1). However, FHR1 deficiency is not enough to cause aHUS, since it is also present in about 5% of Caucasian healthy subjects. In this study we evaluated the prevalence of genetic variants in CFH, CD46, CFI, CFB, C3, and THBD in aHUS patients with anti-FHs, using healthy subjects with FHR1 deficiency, here defined “supercontrols,” as a reference group. “Supercontrols” are more informative than general population because they share at least one risk factor (FHR1 deficiency) with aHUS patients. We analyzed anti-FHs in 305 patients and 30 were positive. The large majority were children (median age: 7.7 [IQR, 6.6–9.9] years) and 83% lacked FHR1 (n = 25, cases) due to the homozygous CFHR3-CFHR1 deletion (n = 20), or the compound heterozygous CFHR3-CFHR1 and CFHR1-CFHR4 deletions (n = 4), or the heterozygous CFHR3-CFHR1 deletion combined with a frameshift mutation in CFHR1 that generates a premature stop codon (n = 1). Of the 960 healthy adult subjects 48 had the FHR1 deficiency (“supercontrols”). Rare likely pathogenetic variants in CFH, THBD, and C3 were found in 24% of cases (n = 6) compared to 2.1% of the “supercontrols” (P-value = 0.005). We also found that the CFH H3 and the CD46GGAAC haplotypes are not associated with anti-FHs aHUS, whereas these haplotypes are enriched in aHUS patients without anti-FHs, which highlights the differences in the genetic basis of the two forms of the disease. Finally, we confirm that common infections are environmental factors that contribute to the development of anti-FHs aHUS in genetically predisposed individuals, which fits with the sharp peak of incidence during scholar-age. Further studies are needed to fully elucidate the complex genetic and environmental factors underlying anti-FHs aHUS and to establish whether the combination of anti-FHs with likely pathogenetic variants or other risk factors influences disease outcome and response to therapies.
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Affiliation(s)
- Elisabetta Valoti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Marta Alberti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Paraskevas Iatropoulos
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Rossella Piras
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Caterina Mele
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Matteo Breno
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Alessandra Cremaschi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Elena Bresin
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Roberta Donadelli
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Silvia Alizzi
- Azienda Ospedaliera-Universitaria, Città della Salute e della Scienza and Department of Medical Sciences, University of Turin, Turin, Italy
| | - Antonio Amoroso
- Azienda Ospedaliera-Universitaria, Città della Salute e della Scienza and Department of Medical Sciences, University of Turin, Turin, Italy
| | - Ariela Benigni
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy.,'L. Sacco' Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Marina Noris
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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