scholarly journals Combination of a Novel Genetic Variant in CFB Gene and a Pathogenic Variant in COL4A5 Gene in a Sibling Renal Disease: A Case Report

2021 ◽  
Vol 12 ◽  
Author(s):  
Feng-mei Wang ◽  
Yan Yang ◽  
Xiao-liang Zhang ◽  
Yan-li Wang ◽  
Yan Tu ◽  
...  
Keyword(s):  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Renal Tissue ◽  
Renal Diseases ◽  
Clinical Feature ◽  
Causative Role ◽  
Complement Factor ◽  
Pathway Activation ◽  
Poor Treatment ◽  
Cfb Gene

Complement factor B (CFB) variants have been described to play a causative role in auto-immune associated C3 glomerulopathy (C3G) and/or atypical hemolytic uremic syndrome (aHUS) by affecting the dysregulations of alternative pathway activation. However, CFB variant concomitant with COL4A5 variant is scarce. Here, we depict two intriguing cases with concurrent novel heterozygosity for CFB c.2054_2057del (p.Ser687Profs∗16) variant and a previous reported COL4A5 c.2999G > T (p.Gly1000Val) variant in a pair of siblings. The clinical feature of either paternal CFB variant or maternal COL4A5 variant is just mild microscopic hematuria. Interestingly, their two children with paternal CFB c.2054_2057del (p.Ser687Profs∗16) variant and maternal COL4A5 c.2999G > T (p.Gly1000Val) variant presented with massive proteinuria, hematuria, and progressive renal failure with poor treatment response. Moreover, complement pathway activation in renal tissue further supports and strengthens the pathogenic role of CFB variant in the development of renal injury in the presence of COL4A5 variant. In conclusion, the rare sibling cases highlight that the extension of genetic analyses in the proband is helpful for the diagnosis and understanding of some family cluster renal diseases.

scholarly journals Novel Complement Factor H mutation, a case report of atypical hemolytic uremic syndrome

2017 ◽  
Vol 4 (2) ◽  
pp. 13 ◽  
Author(s):  
Rodrigo Andrés Sepúlveda ◽  
Rodrigo Tagle ◽  
Aquiles Jara
Keyword(s):  
Renal Failure ◽  
Hemolytic Uremic Syndrome ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Factor H ◽  
Complement Factor H ◽  
Complement Factor ◽  
Severe Renal Failure ◽  
Uremic Syndrome ◽  
I Factor

 Atypical hemolytic uremic syndrome (aHUS) is a rare but catastrophic disease. It is characterized by a triad of microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. When the aHUS is primary, the cause is due to mutations in proteins that regulate the alternative pathway of complement, such as Factor H, Factor I, Factor B, C3, Membrane Co-Factor Protein and Thrombomodulin. Usually primary aHUS is associated with other amplifiers complement factors. We present a case of aHUS in a 25-year-old female patient; she presented with malignant hypertension and severe renal failure. After a widespread study, the etiology of the aHUS was a mutation in the complement factor H, not previously described in the literature (p.Tyr1177His). After treatment with Eculizumab (C5 inhibitor monoclonal antibody), she recovered renal function with not hemodialysis requirements. 

scholarly journals Spontaneous hemolytic uremic syndrome triggered by complement factor H lacking surface recognition domains

2007 ◽  
Vol 204 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Matthew C. Pickering ◽  
Elena Goicoechea de Jorge ◽  
Rubén Martinez-Barricarte ◽  
Sergio Recalde ◽  
Alfredo Garcia-Layana ◽  
...  
Keyword(s):  
Hemolytic Uremic Syndrome ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Risk Haplotype ◽  
Complement Factor ◽  
Age Related ◽  
Uremic Syndrome

Factor H (FH) is an abundant serum glycoprotein that regulates the alternative pathway of complement-preventing uncontrolled plasma C3 activation and nonspecific damage to host tissues. Age-related macular degeneration (AMD), atypical hemolytic uremic syndrome (aHUS), and membranoproliferative glomerulonephritis type II (MPGN2) are associated with polymorphisms or mutations in the FH gene (Cfh), suggesting the existence of a genotype–phenotype relationship. Although AMD and MPGN2 share pathological similarities with the accumulation of complement-containing debris within the eye and kidney, respectively, aHUS is characterized by renal endothelial injury. This pathological distinction was reflected in our Cfh association analysis, which demonstrated that although AMD and MPGN2 share a Cfh at-risk haplotype, the haplotype for aHUS was unique. FH-deficient mice have uncontrolled plasma C3 activation and spontaneously develop MPGN2 but not aHUS. We show that these mice, transgenically expressing a mouse FH protein functionally equivalent to aHUS-associated human FH mutants, regulate C3 activation in plasma and spontaneously develop aHUS but not MPGN2. These animals represent the first model of aHUS and provide in vivo evidence that effective plasma C3 regulation and the defective control of complement activation on renal endothelium are the critical events in the molecular pathogenesis of FH-associated aHUS.

scholarly journals Complement Factor D protects mice from ethanol-induced inflammation and liver injury

2018 ◽  
Vol 315 (1) ◽  
pp. G66-G79 ◽  
Author(s):  
Rebecca L. McCullough ◽  
Megan R. McMullen ◽  
Megan M. Sheehan ◽  
Kyle L. Poulsen ◽  
Sanjoy Roychowdhury ◽  
...  
Keyword(s):  
Liver Injury ◽  
Complement Activation ◽  
Alternative Pathway ◽  
Chronic Ethanol ◽  
Apoptotic Cells ◽  
Complement Factor ◽  
Complement Protein ◽  
Short Term ◽  
Pathway Activation

Complement plays a crucial role in microbial defense and clearance of apoptotic cells. Emerging evidence suggests complement is an important contributor to alcoholic liver disease. While complement component 1, Q subcomponent (C1q)-dependent complement activation contributes to ethanol-induced liver injury, the role of the alternative pathway in ethanol-induced injury is unknown. Activation of complement via the classical and alternative pathways was detected in alcoholic hepatitis patients. Female C57BL/6J [wild type (WT)], C1q-deficient ( C1qa−/−, lacking classical pathway activation), complement protein 4-deficient ( C4−/−, lacking classical and lectin pathway activation), complement factor D-deficient ( FD−/−, lacking alternative pathway activation), and C1qa/FD−/− (lacking classical and alternative pathway activation) mice were fed an ethanol-containing liquid diet or pair-fed control diet for 4 or 25 days. Following chronic ethanol exposure, liver injury, steatosis, and proinflammatory cytokine expression were increased in WT but not C1qa−/−, C4−/−, or C1qa/FD−/− mice. In contrast, liver injury, steatosis, and proinflammatory mediators were robustly increased in ethanol-fed FD−/− mice compared with WT mice. Complement activation, assessed by hepatic accumulation of C1q and complement protein 3 (C3) cleavage products (C3b/iC3b/C3c), was evident in livers of WT mice in response to both short-term and chronic ethanol. While C1q accumulated in ethanol-fed FD−/− mice (short term and chronic), C3 cleavage products were detected after short-term but not chronic ethanol. Consistent with impaired complement activation, chronic ethanol induced the accumulation of apoptotic cells and fibrogenic responses in the liver of FD−/− mice. These data highlight the protective role of complement factor D (FD) and suggest that FD-dependent amplification of complement is an adaptive response that promotes hepatic healing and recovery in response to chronic ethanol. NEW & NOTEWORTHY Complement, a component of the innate immune system, is an important pathophysiological contributor to ethanol-induced liver injury. We have identified a novel role for factor D, a component of the alternative pathway, in protecting the liver from ethanol-induced inflammation, accumulation of apoptotic hepatocytes, and profibrotic responses. These data indicate a dual role of complement with regard to inflammatory and protective responses and suggest that accumulation of apoptotic cells impairs hepatic healing/recovery during alcoholic liver disease.

scholarly journals Amnion epithelial cells are an effective source of factor H and prevent kidney complement deposition in factor H-deficient mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Federica Casiraghi ◽  
Pamela Yossenaidy Rodriguez Ordonez ◽  
Nadia Azzollini ◽  
Marta Todeschini ◽  
Daniela Rottoli ◽  
...  
Keyword(s):  
Kidney Transplantation ◽  
Epithelial Cells ◽  
Complement Activation ◽  
Therapeutic Option ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Factor H ◽  
Complement Factor ◽  
Complement Deposition ◽  
Amnion Epithelial Cells

AbstractComplement factor H (FH) is the main plasma regulator of the alternative pathway of complement. Genetic and acquired abnormalities in FH cause uncontrolled complement activation amplifying, with the consequent accumulation of complement components on the renal glomeruli. This leads to conditions such as C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS). There is no effective therapy for these diseases. Half of the patients progress to end-stage renal disease and the condition recurs frequently in transplanted kidneys. Combined liver/kidney transplantation is a valid option for these patients, but the risks of the procedure and donor organ shortages hamper its clinical application. Therefore, there is an urgent need for alternative strategies for providing a normal FH supply. Human amnion epithelial cells (hAEC) have stem cell characteristics, including the capability to differentiate into hepatocyte-like cells in vivo.Here, we administered hAEC into the livers of newborn Cfh−/− mice, which spontaneously developed glomerular complement deposition and renal lesions resembling human C3G. hAEC engrafted at low levels in the livers of Cfh−/− mice and produced sufficient human FH to prevent complement activation and glomerular C3 and C9 deposition. However, long-term engraftment was not achieved, and eventually hAEC elicited a humoral immune response in immunocompetent Cfh−/− mice.hAEC cell therapy could be a valuable therapeutic option for patients undergoing kidney transplantation in whom post-transplant immunosuppression may protect allogeneic hAEC from rejection, while allogeneic cells provide normal FH to prevent disease recurrence.

scholarly journals Case Report: A Rare Truncating Variant of the CFHR5 Gene in IgA Nephropathy

2021 ◽  
Vol 12 ◽  
Author(s):  
Gabriella Guzzo ◽  
Salima Sadallah ◽  
Heidi Fodstad ◽  
Jean-Pierre Venetz ◽  
Samuel Rotman ◽  
...  
Keyword(s):  
Iga Nephropathy ◽  
Association Studies ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Factor H ◽  
Genome Wide Association Studies ◽  
Complement Factor ◽  
Loss Of Function ◽  
Renal Disease Progression ◽  
Therapeutic Implications

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Despite appropriate therapy, 20–40% of affected-patients evolve toward end-stage kidney disease (ESKD). Mesangial IgA deposits are the hallmark of IgAN, and complement deposition (C3) seems to differentiate latent IgA mesangial deposits from active IgAN. Atypical hemolytic uremic syndrome (aHUS), another disease in which complement plays an important role, is caused by inherited or acquired deregulation of the alternative pathway (AP) of complement. A subgroup of IgAN shows thrombotic microangiopathy (TMA) lesions in kidney biopsies, the histological characteristic of aHUS. Genetic variants of complement Factor H (CFH), known to be present in aHUS, have been associated with rapidly progressive forms of IgAN and a clinical pattern of aHUS. Genome-wide association studies (GWAS) have confirmed that the 1q32 region, encoding for CFH and its related proteins, is an IgAN susceptibility locus. A 30 year-old man was admitted for seizures and malignant hypertension. The kidney biopsy showed IgAN associated with features of TMA. Despite five plasma exchanges, the patient remained dialysis-dependent, and ESKD was diagnosed. Functional and genetic complement analysis were performed. A monoallelic protein-truncating, likely loss-of-function variant was identified in the CFHR5 gene. Eculizumab is the treatment of aHUS. As it has been successfully used in a few cases of rapidly progressive IgAN, it was decided to administer eculizumab over a period of 12 months in addition to the usual immunosuppression for renal transplantation. After a follow-up of 3 years, there was no clinical disease recurrence. Systematic biologic and genetic screening of complement in individuals with IgAN might be useful to better delineate the role of the AP of complement in renal disease progression, and this may have therapeutic implications.

scholarly journals COVID-19: a trigger for severe thrombotic microangiopathy in a patient with complement gene variant

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Larisa Pinte ◽  
Bogdan Marian Sorohan ◽  
Zoltán Prohászka ◽  
Mihaela Gherghiceanu ◽  
Cristian Băicuş
Keyword(s):  
Hemolytic Uremic Syndrome ◽  
Thrombotic Microangiopathy ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Factor H ◽  
Complement C3 ◽  
Uncontrolled Hypertension ◽  
Complement Factor ◽  
Uremic Syndrome ◽  
Complement Gene

Abstract The evidence regarding thrombotic microangiopathy (TMA) related to Coronavirus Infectious Disease 2019 (COVID-19) in patients with complement gene mutations as a cause of acute kidney injury (AKI) are limited. We presented a case of a 23-year-old male patient admitted with an asymptomatic form of COVID-19, but with uncontrolled hypertension and AKI. Kidney biopsy showed severe lesions of TMA. In evolution patient had persistent microangiopathic hemolytic anemia, decreased level of haptoglobin and increased LDH level. Decreased complement C3 level and the presence of schistocytes were found for the first time after biopsy. Kidney function progressively decreased and the patient remained hemodialysis dependent. Complement work-up showed a heterozygous variant with unknown significance in complement factor I (CFI) c.-13G>A, affecting the 5' UTR region of the gene. In addition, the patient was found to be heterozygous for the complement factor H (CFH) H3 haplotype (involving the rare alleles of c.-331C>T, Q672Q and E936D polymorphisms) reported as a risk factor of atypical hemolytic uremic syndrome. This case of AKI associated with severe TMA and secondary hemolytic uremic syndrome highlights the importance of genetic risk modifiers in the alternative pathway dysregulation of the complement in the setting of COVID-19, even in asymptomatic forms.

scholarly journals Direct activation of the alternative complement pathway by SARS-CoV-2 spike proteins is blocked by factor D inhibition

Blood ◽  
2020 ◽  
Vol 136 (18) ◽  
pp. 2080-2089 ◽  
Author(s):  
Jia Yu ◽  
Xuan Yuan ◽  
Hang Chen ◽  
Shruti Chaturvedi ◽  
Evan M. Braunstein ◽  
...  
Keyword(s):  
Complement Activation ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Factor H ◽  
Spike Protein ◽  
Target Cells ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Complement Factor ◽  
Spike Proteins

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious respiratory virus that can lead to venous/arterial thrombosis, stroke, renal failure, myocardial infarction, thrombocytopenia, and other end-organ damage. Animal models demonstrating end-organ protection in C3-deficient mice and evidence of complement activation in humans have led to the hypothesis that SARS-CoV-2 triggers complement-mediated endothelial damage, but the mechanism is unclear. Here, we demonstrate that the SARS-CoV-2 spike protein (subunit 1 and 2), but not the N protein, directly activates the alternative pathway of complement (APC). Complement-dependent killing using the modified Ham test is blocked by either C5 or factor D inhibition. C3 fragments and C5b-9 are deposited on TF1PIGAnull target cells, and complement factor Bb is increased in the supernatant from spike protein–treated cells. C5 inhibition prevents the accumulation of C5b-9 on cells, but not C3c; however, factor D inhibition prevents both C3c and C5b-9 accumulation. Addition of factor H mitigates the complement attack. In conclusion, SARS-CoV-2 spike proteins convert nonactivator surfaces to activator surfaces by preventing the inactivation of the cell-surface APC convertase. APC activation may explain many of the clinical manifestations (microangiopathy, thrombocytopenia, renal injury, and thrombophilia) of COVID-19 that are also observed in other complement-driven diseases such as atypical hemolytic uremic syndrome and catastrophic antiphospholipid antibody syndrome. C5 inhibition prevents accumulation of C5b-9 in vitro but does not prevent upstream complement activation in response to SARS-CoV-2 spike proteins.

Regulation of Complement Activation by Thrombomodulin.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 5127-5127
Author(s):  
Mieke Delvaeye ◽  
Astrid DeVriese ◽  
Michael Moons ◽  
Naomi Esmon ◽  
Charles Esmon ◽  
...  
Keyword(s):  
Complement Activation ◽  
Conflicts Of Interest ◽  
Vascular Endothelial Cells ◽  
Leukocyte Adhesion ◽  
Alternative Pathway ◽  
Atypical Hemolytic Uremic Syndrome ◽  
Negative Regulator ◽  
Classical Pathway ◽  
Complement Factor ◽  
Wide Range

Abstract Abstract 5127 Thrombomodulin (TM) is an integral membrane glycoprotein, ubiquitously expressed by vascular endothelial cells. Its epidermal growth factor (EGF)-like repeats amplify thrombin-mediated generation of activated protein C and activated thrombin activatable fibrinolysis inhibitor, thereby suppressing coagulation, inflammation and fibrinolysis, and inactivating the anaphylatoxins, C3a and C5a. TM also has direct anti-inflammatory properties, interfering with leukocyte adhesion, and preventing complement activation via its lectin-like domain. We recently established that TM is a physiologically important negative regulator of the alternative pathway (AP) of complement activation, defects of which increase the risk of the thrombotic microangiopathy, atypical hemolytic uremic syndrome. In this report, we assessed the role of TM in the other complement activation pathways. In serum, TM interferes with classical pathway (CP) mediated erythrocyte cell lysis, and protects against CP-induced cell death. TM co-precipitates with C4b, and enhances its inactivation and cleavage to C4c and C4d by complement factor I in the presence of the cofactor C4b binding protein. TM also interferes with the coagulation complement pathway by interfering with thrombin cleavage and activation of C5 to C5a. Overall, TM negatively regulates complement via the major recognized pathways. The findings implicate defects in TM in a wide range of diseases in which complement plays a role, and underlines the potential of TM as a therapeutic target. Disclosures No relevant conflicts of interest to declare.

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