Complement factor H levels are decreased and correlated with serum C-reactive protein in late-onset Alzheimer's disease / Os níveis de fator H do complemento estão diminuídos e correlacionados com a proteína C-reativa sérica na doença de Alzheimer de início tardio

Abstract Alzheimer's disease (AD) is the most common cause of dementia. Despite numerous studies on the subject, the pathologies for AD are still unclear and there is still no ideal biomarker for diagnosis. The present study aimed to investigate clinical significance of human complement factor H (CFH) in patients with late-onset AD. Methods: The present prospective study included 187 late-onset AD patients who went to our hospital from January 2015 to December 2017. One hundred patients with mild cognitive impairment (MCI) and 80 healthy individuals who were age and gender matched to AD patients were enrolled as controls. Demographic data such as age, gender, and education duration were recorded. Blood samples were collected and serum levels of C-reactive protein (CRP), CFH, and brain-derived neurotrophic factor (BDNF) were determined by Enzyme-linked immunosorbent assay (ELISA). The mini-mental state examination (MMSE) score was measured for all patients. Results: No significant difference was found in age, gender, and education duration for all participants. The MMSE scores showed AD patients had lower MMES scores than the other two groups. All factors of CFH, CRP, and BDNF were dramatically decreased in AD patients compared with the MCI and the ealthy control. Levels of CFH were found to be positively correlated with levels of CRP; however, no significant correlation was found between CFH and BDNF, nor CFH and MMSE. Conclusion: CFH was decreased in late-onset AD patients, and serum levels of CFH was correlated with serum levels of CRP, but not MMSE and BDNF. These results may provide more clinical evidences for the role of CFH in AD patients.

Resumo A doença de Alzheimer (DA) é a causa mais comum de demência. Apesar de inúmeros estudos sobre DA, suas patologias ainda não são claras e ainda não existe um biomarcador ideal para o diagnóstico da condição. O presente estudo teve como objetivo investigar a significância clínica do fator H do complemento humano (CFH) em pacientes com DA de início tardio. Métodos: O presente estudo prospectivo incluiu um total de 187 pacientes com DA de início tardio que foram ao nosso hospital entre janeiro de 2015 e dezembro de 2017. Cem pacientes com comprometimento cognitivo leve (CCL) e 80 indivíduos saudáveis com idade e sexo pareados com pacientes com DA foram incluídos como controle. Dados demográficos como idade, sexo e duração da educação foram registrados. As amostras de sangue foram coletadas e os níveis séricos de proteína C-reativa (PCR), CFH e fator neurotrófico derivado do cérebro (BDNF) foram determinados pelo ensaio imunoabsorvente ligado à enzima (ELISA). O escore do miniexame do estado mental (MEEM) foi medido para todos os pacientes. Resultados: Não foram encontradas diferenças significativas em idade, sexo e duração da educação para todos os participantes. Pacientes com DA tinham os menores escores de MEEM em relação aos outros dois grupos. Todos os fatores de CFH, PCR e BDNF diminuíram drasticamente em pacientes com DA em comparação com o CCL e o controle saudável. Os níveis de CFH mostraram correlação positiva com os níveis de PCR; no entanto, não foi encontrada correlação significativa entre CFH e BDNF, nem CFH e MEEM. Conclusão: A CFH diminuiu nos pacientes com DA de início tardio e os níveis séricos de CFH foram correlacionados com os níveis séricos de PCR, mas não o MEEM e o BDNF. Esses resultados podem fornecer mais evidências clínicas do papel da CFH em pacientes com DA.

Atypical Hemolytic Uremic Syndrome in a 13-year-old Lao Girl: A Case Report

Atypical hemolytic uremic syndrome (aHUS), a rare form of thrombotic microangiopathy, is distinguished from the typical form by the absence of a preceding verotoxin-producing Escherichia coli infection. Notably, aHUS occurs in association with genetic or acquired disorders causing dysregulation of the alternative complement pathway. Patients with aHUS may show the presence of anti-complement factor H (CFH) autoantibodies. This acquired form of aHUS (anti-CFH-aHUS) primarily affects children aged 9–13 years. We report a case of a 13-year-old Lao girl with clinical features of aHUS (most likely anti-CFH-aHUS). The initial presentation of the patient met the classical clinical triad of thrombotic microangiopathy (microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury) without preceding diarrheal illness. Low serum levels of complement 3 and normal levels of complement 4 indicated abnormal activation of the alternative complement pathway. Plasma infusion and high-dose corticosteroid therapy resulted in improvement of the renal function and hematological profile, although the patient subsequently died of infectious complications. This is the first case report that describes aHUS (possibly anti-CFH-aHUS) in Laos.

Immunological mechanisms of Neisseria gonorrhoeae infection: An update / 中华男科学杂志

Neisseria gonorrhoeae (NG), as a pathogen of gonorrhea, is strictly limited to growth on the human host. In case of gonococcal infection, the body may recruit such inflammatory cells as neutrophils to resist the invasion of NG or initiate its adaptive immune response by antigen presentation to eliminate the pathogen. However, a series of immune escape mechanisms of NG make it difficult to clear up the infection. In the innate immune system, NG can not only secrete thermonuclease to degrade neutrophile granulocytes, inhibit respiratory burst to resist killing by neutrophils, activate NLRP3 to prompt the pyronecrosis of inflammatory cells, but also regulate the differentiation of macrophages to reduce the inflammatory response, combine with factor H to evade complement-mediated killing. NG infection can hardly give rise to effective adaptive immune response and immune memory, but can promote TGF-β production to inhibit Th1/Th2-mediated adaptive immune response, bind to CEACAM1 on the B cell surface to promote apoptosis in B cells, and combine with CEACAM1 on the T cell surface to inhibit helper T cell proliferation, which makes it difficult for B cells to produce high-affinity specific antibodies. With the increasing drug-resistance of NG, immunological studies may play a significant role in the development of novel therapies and effective vaccines against the infection.

Kidney Transplantation in Patients with Atypical Hemolytic Uremic Syndrome due to Complement Factor H Deficiency: Impact of Liver Transplantation

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare disease that is often associated with genetic defects. Mutations of complement factor H (CFH) are the most common genetic defects that cause aHUS and often result in end-stage renal disease. Since CFH is mainly produced in the liver, liver transplantation (LT) has been performed in patients with defective CFH. METHODS: The clinical courses of four kidney allograft recipients who lost their native kidney functions due to aHUS associated with a CFH mutation were reviewed. RESULTS: Subject A underwent kidney transplantation (KT) twice, aHUS recurred and the allograft kidney failed within a few years. Subject B received a KT and soon experienced a recurrence of aHUS coinciding with infection. Her allograft kidney function has worsened, and she remains on plasma infusion therapy. Subject C underwent LT followed by KT. She is doing well without plasma infusion therapy after combined LT-KT for 3 years. Subject D received KT following LT and is now recurrence-free from aHUS. CONCLUSION: In patients with aHUS associated with a CFH mutation, KT without LT was complicated with a recurrence of aHUS, which might lead to allograft loss. Conversely, LT was successful in preventing the recurrence of aHUS and thus might be another option for a recurrence-free life for aHUS patients associated with CFH mutation.

Absenteísmo-doença no serviço público municipal de Goiânia / Sickness absence in a municipal public service of Goiânia, Brazil

INTRODUÇÃO: O absenteísmo-doença, enquanto falta ao trabalho justificada por licença médica, é um importante indicador das condições de saúde dos trabalhadores. Em geral, características sociodemográficas e ocupacionais situam-se entre os principais fatores associados ao absenteísmo-doença. A administração pública é responsável por 21,8% dos empregos formais no Brasil. Esta população permite o estudo de uma grande variedade de categorias profissionais. OBJETIVO: Analisar o perfil e os indicadores de absenteísmo-doença entre servidores municipais de Goiânia, no Estado de Goiás, Brasil. Métodos: Estudo transversal das licenças certificadas para tratamento de saúde superiores a três dias, de todos os servidores, desde janeiro de 2005 a dezembro de 2010. Foram calculadas as prevalências, utilizando como critérios o número de indivíduos, os episódios e os dias de afastamento. RESULTADOS: Foram concedidas 40.578 licenças certificadas para tratamento de saúde a 13.408 servidores numa população média anual de 17.270 pessoas, o que resultou em 944.722 dias de absenteísmo. A prevalência acumulada de licença no período foi de 143,7%, com média anual de 39,2% e duração de 23 dias por episódio. A prevalência acumulada de absenteísmo-doença foi maior entre mulheres (52,0%) com idade superior a 40 anos (55,9%), com companheiro (49,9%), de baixa escolaridade (54,4%), profissionais de educação (54,7%), > 10 anos de serviço (61,9%) e múltiplos vínculos profissionais (53,7%). Os grupos de diagnósticos (CID-10) com as maiores prevalências acumuladas de licenças foram os do capítulo de transtornos mentais (26,5%), doenças osteomusculares (25,1%) e lesões (23,6%). CONCLUSÕES: Os indicadores de absenteísmo-doença expressam a magnitude desse fenômeno no serviço público e podem auxiliar no planejamento das ações de saúde do trabalhador, priorizando os grupos ocupacionais mais vulneráveis. .

BACKGROUND: Sickness absence, as work absenteeism justified by medical certificate, is an important health status indicator of the employees and, overall, sociodemographic and occupational characteristics are among the main factors associated with sickness absence. Public administration accounts for 21.8% of the formal job positions in Brazil. This population allows the study of a wide range of professional categories. OBJECTIVE: To assess the profile and indicators of sickness absence among public workers from the municipality of Goiania, in the State of Goiás, Brazil. METHODS: A cross-sectional study on certified sick leaves, lasting longer than three days, of all civil servants from January 2005 to December 2010. Prevalence rates were calculated using as main criteria the number of individuals, episodes and sick days. RESULTS: 40,578 certified sick leaves were granted for health treatment among 13,408 public workers, in an annual average population of 17,270 people, which resulted in 944,722 days of absenteeism. The cumulative prevalence of sick leave for the period was of 143.7%, with annual average of 39.2% and duration of 23 days per episode. The cumulative prevalence of sickness absence was higher among women (52.0%), older than 40 years old (55.9%), with a partner (49.9%), low schooling (54.4%), education professionals (54.7%), > 10 years of service (61.9%), and with multiple work contracts (53.7%). Diagnoses groups (ICD-10) with higher cumulative prevalence of sick leaves were those with mental disorders (26.5%), musculoskeletal diseases (25.1%), and injuries (23.6%). CONCLUSIONS: Indicators of sickness absence express the magnitude of this phenomenon in the public sector and can assist in planning health actions for the worker, prioritizing the most vulnerable occupational groups. .

Complement regulation: physiology and disease relevance / 소아과

The complement system is part of the innate immune response and as such defends against invading pathogens, removes immune complexes and damaged self-cells, aids organ regeneration, confers neuroprotection, and engages with the adaptive immune response via T and B cells. Complement activation can either benefit or harm the host organism; thus, the complement system must maintain a balance between activation on foreign or modified self surfaces and inhibition on intact host cells. Complement regulators are essential for maintaining this balance and are classified as soluble regulators, such as factor H, and membrane-bound regulators. Defective complement regulators can damage the host cell and result in the accumulation of immunological debris. Moreover, defective regulators are associated with several autoimmune diseases such as atypical hemolytic uremic syndrome, dense deposit disease, age-related macular degeneration, and systemic lupus erythematosus. Therefore, understanding the molecular mechanisms by which the complement system is regulated is important for the development of novel therapies for complement-associated diseases.

Atypical HUS caused by anti-complement factor H antibody: a hematologist's perspective

No abstract available.

CFH Y402H polymorphism and response to intravitreal Ranibizumab in brazilian patients with neovascular age-related macular degeneration / Associação do polimorfismo Y402H do gene CFH com a resposta terapêutica ao Ranibizumabe em pacientes portadores de degeneração macular relacionada à idade neovascular

Objective: To investigate the association between CFH gene polymorphism and response to ranibizumab in Brazilian patients with neovascular age-related macular degeneration (AMD). Methods: 95 patients were genotyped for the CFH rs1061170 (Y402H) single nucleotide polymorphism. Patients with neovascular AMD initially received intravitreal ranibizumab injections for three months and were retreated as needed. Visual acuity (VA) and central retinal thickness (CRT) were measured before treatment and at 1, 3, 6, and 12 months post-treatment. Results: For patients with the TT and TC genotypes, paired comparisons of VA showed a statistically significant improvement when the data obtained at all visits were compared with baseline. Patients homozygous for the risk genotype (CC) did not show a statistically significant improvement when VA obtained at visits 1, 3, 6 and 12 were compared with baseline. For all genotypes, paired comparisons of CRT showed a statistically significant improvement when the data obtained at visits 1, 3, 6 and 12 were compared with baseline. Conclusion: Patients with the CC genotype showed poorer long-term functional response to intravitreal ranibizumab. .

Objetivo: investigar a associação entre polimorfismo do gene CFH e a resposta terapêutica ao ranibizumabe na degeneração macular relacionada à idade (DMRI) neovascular. Métodos: noventa e cinco pacientes foram submetidos à genotipagem para identificação do polimorfismo rs1061170 (Y402H) do gene CFH. Pacientes portadores de DMRI neovascular receberam inicialmente três injeções intravítreas de ranibizumabe com intervalo mensal entre elas. A partir de então, foram retratados de acordo com a necessidade. Acuidade visual (AV) e espessura macular central (EMC) foram medidas antes e 1, 3, 6 e 12 meses após o início do tratamento. Resultados: para pacientes portadores dos genótipos TT e TC, a análise pareada da AV mostrou melhora estatisticamente significativa quando os dados obtidos em todas as visitas foram comparados com aqueles obtidos antes do início do tratamento. Para pacientes homozigotos para o alelo de risco (CC), não houve diferença estatisticamente significativa quando a AV obtida nas visitas 1, 3, 6 e 12 foi comparada com aquela obtida antes do início do tratamento. Para todos os genótipos, a análise pareada da EMC mostrou melhora estatisticamente significativa em todas as avaliações. Conclusão: pacientes portadores do genótipo CC apresentaram pior resposta funcional em longo prazo após o tratamento com ranibizumabe intravítreo. .

Clinical characteristies of atypical hemolytie uremic syndrome associated with H factor antibody in children / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the clinical characteristics, renal pathology, treatment and prognosis of children with atypical hemolytic uremic syndrome associated with H factor antibody.</p><p><b>METHOD</b>Four children less than 18 yr of age admitted from Nov. 2010 to May 2011 in Peking University First Hospital were included. They all met the criteria for atypical hemolytic uremic syndrome and with positive serum anti factor H antibody. They aged from 5 to 11 yr. Data on clinical manifestations, renal pathology, treatment and prognosis were analyzed.</p><p><b>RESULT</b>All of the 4 cases had gastrointestinal symptoms such as vomiting, abdominal pain, or abdominal distension. None of them had diarrhea. Two children had hypertension. One child had episodes of convulsion. One child had history of atypical hemolytic uremic syndrome. All of them had low serum complement C3. Three of them had low serum factor H (38.0, 88.4, 209.4 mg/L). All of them had serum antibody to factor H (1: 7 068, 1: 1 110, 1: 174, and 1: 869). Three of them received renal biopsy, all of them showed thrombotic microangiopathy. All of them were treated with steroid combined with mycophenolate mofetil. Two children received plasma exchange. They were followed up for 8 to 29 months. The renal function became normal and proteinuria relieved in all of them. The serum factor H concentration increased to 405.8, 155.8 and 438.4 mg/L, respectively. The titer of anti factor H antibody decreased to 1: 119, 1: 170, 1: 123, and 1: 674, respectively.</p><p><b>CONCLUSION</b>Gastrointestinal symptom is common in children with atypical hemolytic uremic syndrome associated with H factor antibody. Hypocomplementemia was observed in all of them. Steroid combined with mycophenolate mofetil seemed to be effective for them. The monitoring of serum factor H and antibody to factor H may help diagnosis and treatment.</p>

Anesthetic management of living donor liver transplantation for complement factor H deficiency hemolytic uremic syndrome: a case report / 대한마취과학회지

We experienced a living donor liver transplantation for a 26-month-old girl with complement factor H deficiency. Complement factor H is a plasma protein that regulates the activity of the complement pathway. Complement overactivity induced by complement factor H deficiency is associated with atypical hemolytic uremic syndrome. Liver transplantation can be the proper treatment for this condition. During the liver transplantation of these patients, prevention of the complement overactivation is necessary. Minimizing complement activation, through the use of modalities such as plasma exchange before the surgery and transfusion of fresh frozen plasma throughout the entire perioperative period, may be the key for successful liver transplantation in these patients.

Importance of genetic polymorphisms in the response to age-related macular degeneration treatment / Importância dos polimorfismos genéticos na resposta terapêutica da degeneração macular relacionada à idade

Age-related macular degeneration (AMD) is a degenerative disorder that affects the central retina and involves the Bruch's membrane, the retinal pigment epithelium and the photoreceptors. Recent studies have shown that polymorphisms of the CFH, LOC387715 and VEGF genes are associated with AMD. Herein, we review the literature to analyze the association between the main genetic polymorphisms and the response to the existing therapeutic modalities. Patients with CFH high-risk alleles show a poorer response to preventive treatment of AMD with antioxidants and zinc.The association between genetic polymorphisms and response to photodynamic therapy and antiangiogenic drugs, however, is controversial until now.

A degeneração macular relacionada à idade (DMRI) é uma doença degenerativa que afeta a retina central e envolve a membrana de Bruch, o epitélio pigmentar da retina e os fotorreceptores. Estudos recentes têm mostrado que polimorfismos dos genes CFH, LOC387715 e VEGF estão associados com a DMRI. Neste trabalho, é feita uma revisão da literatura para análise da associação entre os principais polimorfismos genéticos e a resposta às diferentes modalidades terapêuticas existentes. Observa-se que os pacientes portadores dos alelos de risco do gene CFH apresentam uma pior resposta ao tratamento preventivo da DMRI com antioxidantes e zinco. Já a associação entre o polimorfismo genético e a resposta à terapia fotodinâmica e às drogas antiangiogênicas é, até o momento, controversa.

Association study between age-related macular degeneration and R1210C mutation of CFH gene in Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>A R1210C mutation of complement factor H (CFH) gene has been associated with age-related macular degeneration (AMD) in Caucasian population. This study was to verify above association in Han Chinese population.</p><p><b>METHODS</b>The mutation was detected by direct sequencing in 258 patients with wet AMD and 426 matched controls.</p><p><b>RESULTS</b>The R1210C mutation has not been identified in either sample.</p><p><b>CONCLUSION</b>The R1210C mutation in CFH gene is not associated with AMD in Han Chinese population.</p>

Characteristics of pediatric C3 glomerulopathy with decreased factor H in 3 cases / 中华儿科杂志

<p><b>OBJECTIVE</b>To study the characteristics of clinicopathology and prognosis of 3 pediatric cases diagnosed as C3 glomerulopathy, and to improve the understanding of C3 glomerulopathy in children.</p><p><b>METHOD</b>The medical record, plasma complement C3, Factor H (FH) and its autoantibody, and therapeutic response of the 3 cases were analyzed, and their prognosis were followed up.</p><p><b>RESULT</b>Of the 3 cases, 2 were male and 1 was female, the age of onset was 9 years, 12 years, 5 years 4 months, the duration from onset to renal biopsy was 3 months, 7 months and 20 days, and the follow-up period were 2.6 years, 8 months and 1.5 years respectively.</p><p><b>CLINICAL MANIFESTATIONS</b>All the 3 cases showed microscopic hematuria, with or without gross hematuria and proteinuria. Two showed persistently decreased plasma complement C3, in the other one C3 was in normal lower limit, all presented with decreased FH concertration, in 1 case anti-FH antibody was positive. Their clinical diagnosis was post-streptococcal glomerulonephritis, nephrotic syndrome (NS) nephritis type, and mesangial proliferative glomerulonephritis respectively.</p><p><b>PATHOLOGICAL FINDINGS</b>All showed evident deposition of C3 on glomerular basement membrance (GBM) and mesangial region by immunofluorescence (IF) and electron dense deposit in GBM, mesangial region or para-mesangial region by Electron microscopic (EM) examination Treatment and prognosis: The case with NS showed no response to steroid, so steroid was gradually stopped after renal biopsy and replaced by angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor antagonist (ARB). The other two cases were treated with ACEI and renal protective treatment. Of the 3 cases, one gradually showed elevated serum creatinine (Scr) and decreased creatinine clearance rate (Ccr), the other two were normal, but slightly increased indications for early kidney injury.</p><p><b>CONCLUSION</b>C3 glomerulopathy is characterized by evident C3 deposition under IF. Its clinical and pathological manifestations vary a lot. The decreased plasma C3 and FH suggest that the abnormal regulation of complement system play an importment role in its pathogenesis.</p>

Caracterización inmunohistoquímica de la función renal en un riñón transplantado en paciente portador de síndrome urémico hemolítico atípico por déficit de factor H: [revisión] / Immunohistochemical characterization of the renal function in transplanted kidney in a carrier of an atypical uremic haemolitic syndrome due to factor H deficit: [review]

El síndrome urémico hemolítico se caracteriza por presentar anemia hemolítica microangiopática, trombocitopenia e insuficiencia renal aguda. Se clasifica en típico, diarrea positivo, inducido por Escherichia coli 0157-H7 (90%) y atípico, más comúnmente secundario a la desregulación de la vía alternativa del complemento (3-10%). La región cromosómica 1q32 contiene el sistema regulador de la activación del complemento humano (RCA). Se relaciona con mutaciones en factores reguladores de C3 como el factor H (FH, la más común), el factor I, el factor B y la proteína constitutiva de membrana (MCP). Presenta patrones de herencia autosómica tanto dominante como recesiva. El déficit de FH autosómico dominante generalmente ocurre en adultos y la mortalidad y el riesgo de enfermedad renal terminal oscila entre el 50%-90%. El objetivo de nuestro trabajo fue estudiar la función tubular y glomerular por técnicas de inmunohistoquímica para detectar mecanismos de transporte para agua (AQPs), urea (UT-A) y proteínas (nefrina, podocalixina y megalina) en un riñón transplantado de un paciente portador de SUH por déficit de FH que desarrolló una recidiva de SUH y lesiones por nefrotoxicidad. Detectamos un mecanismo de adaptación a la uremia por la expresión de novo de un UT-A2 en corteza renal y la disminución del UT-A1 en médula y alteraciones en el manejo proximal del agua por la disminución de la expresión de AQP1 en túbulo proximal. Las modificaciones a nivel de la expresión de la nefrina y la podocalixina podocitarias y de megalina en el túbulo proximal podrían explicar la presencia de proteinuria.

Interactions of complement proteins C1q and factor H with lipid A and Escherichia coli: further evidence that factor H regulates the classical complement pathway

Proteins of the complement system are known to interact with many charged substances. We recently characterized binding of C1q and factor H to immobilized and liposomal anionic phospholipids. Factor H inhibited C1q binding to anionic phospholipids, suggesting a role for factor H in regulating activation of the complement classical pathway by anionic phospholipids. To extend this finding, we examined interactions of C1q and factor H with lipid A, a well-characterized activator of the classical pathway. We report that C1q and factor H both bind to immobilized lipid A, lipid A liposomes and intact Escherichia coli TG1. Factor H competes with C1q for binding to these targets. Furthermore, increasing the factor H: C1q molar ratio in serum diminished C4b fixation, indicating that factor H diminishes classical pathway activation. The recombinant forms of the Cterminal, globular heads of C1q A, B and C chains bound to lipid A and E. coli in a manner qualitatively similar to native C1q, confirming that C1q interacts with these targets via its globular head region. These observations reinforce our proposal that factor H has an additional complement regulatory role of down-regulating classical pathway activation in response to certain targets. This is distinct from its role as an alternative pathway down-regulator. We suggest that under physiological conditions, factor H may serve as a downregulator of bacterially-driven inflammatory responses, thereby fine-tuning and balancing the inflammatory response in infections with Gram-negative bacteria.

Complement activation by phospholipids: the interplay of factor H and C1q

Complement proteins in blood recognize charged particles. The anionic phospholipid (aPL) cardiolipin binds both complement proteins C1q and factor H. C1q is an activator of the complement classical pathway, while factor H is an inhibitor of the alternative pathway. To examine opposing effects of C1q and factor H on complement activation by aPL, we surveyed C1q and factor H binding, and complement activation by aPL, either coated on microtitre plates or in liposomes. Both C1q and factor H bound to all aPL tested, and competed directly with each other for binding. All the aPL activated the complement classical pathway, but negligibly the alternative pathway, consistent with accepted roles of C1q and factor H. However, in this system, factor H, by competing directly with C1q for binding to aPL, acts as a direct regulator of the complement classical pathway. This regulatory mechanism is distinct from its action on the alternative pathway. Regulation of classical pathway activation by factor H was confirmed by measuring C4 activation by aPL in human sera in which the C1q:factor H molar ratio was adjusted over a wide range. Thus factor H, which is regarded as a down-regulator only of the alternative pathway, has a distinct role in downregulating activation of the classical complement pathway by aPL. A factor H homologue, β2-glycoprotein-1, also strongly inhibits C1q binding to cardiolipin. Recombinant globular domains of C1q A, B and C chains bound aPL similarly to native C1q, confirming that C1q binds aPL via its globular heads.

A Case of Familial Atypical Hemolytic Uremic Syndrome Associated with Complement Factor H Mutation in Adults / 대한신장학회지

The hemolytic uremic syndrome is a clinical syndrome defined by the presence of thrombocytopenia, microangiopathic hemolytic anemia and acute renal failure. Atypical hemolytic uremic syndrome (aHUS) which is not usually associated with prodromal symptoms, especially diarrhea, has a higher mortality rate and a stronger tendency to progress to chronic renal failure. In approximately 30-50% of patients with aHUS, mutations have been detected in complement factor H, membrane cofactor protein or factor I. Mutations in the complement regulator factor H are the most frequent and have a very poor prognosis, with most patients developing ESRD. We have experienced a 33-year-old man with a family history of renal failure diagnosed as aHUS resulted from factor H mutation, for whom we carried out hemodialysis, plasmapheresis and other conservative management.

Genetic variants in three genes and smoking show strong associations with susceptibility to exudative age-related macular degeneration in a Chinese population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The present study was undertaken to replicate the associations of representative polymorphisms in three genes (complement factor H (CFH), complement factor B (BF) and HtrA serine peptidase 1 (HTRA1)) with exudative age-related macular degeneration (AMD) in a Han Chinese population, and to test if the modifiable environmental factors affect AMD susceptibility associated with different type of genotype in these genes.</p><p><b>METHODS</b>An age, gender and ethnicity matched case-control study was conducted to genotype the representative single neucleotide polymorphisms (SNPs) loci including rs1061170 and rs1410996 in CFH, rs641153 and rs4151667 in BF and rs11200638 in HTRA1 gene in 144 exudative AMD patients and 126 normal controls using PCR-RFLP and direct resequencing. The demographic characteristics and behavioral risk factors were also recorded. Allelic and genotypic associations for individual SNP and joint associations with two loci were performed. The gene-gene and gene-environment interactions were analyzed using multivariate non-conditional Logistic regression analysis.</p><p><b>RESULTS</b>The C risk allele frequencies for CFH Y402H (rs1061170) in cases and controls were 12.5% and 5.4% respectively, which were much lower than those in Caucasians (P < 0.001). Compared with TT homozygous genotype, the CT heterozygous genotype was positively associated with AMD with odds ratio (OR) of 3.23 (1.36 - 5.07). However, the population attributable risk (PAR) of C allele was only 3.3% (1.4% - 4.3%). rs1410996 was also associated with AMD independent of Y402H. The ORs of exudative AMD for individuals carrying one copy risk allele and two copy risk alleles were 2.57 (1.21 - 5.45) and 4.76 (2.15 - 10.55) respectively, with correspondent PARs of 28.3% (2.0% - 40.5%) and 38.2% (21.8% - 45.4%). rs11200638 in HTRA1 was another susceptible locus for AMD and the risk homozygotes were significantly susceptible for exudutive AMD (OR = 3.98, 1.88 - 8.43) with PAR of 38.9% (24.3% - 45.8%). Education status and cigarette smoking were also related to exudative AMD. After controlling for environmental risk factors, CFH and HTRA1 SNPs were independently associated with exudative AMD, with OR of 3.50 (1.45 - 8.45) for CT genotype in Y402H, 3.34 (1.33 - 8.36) for GG genotype in rs1410996 and 3.85 (1.58 - 9.42) for AA genotype in rs11200638 respectively. The interaction analysis between gene and environmental factors showed that smoking synergistically increased susceptibility of AMD for heterozygotes of rs1410996, with OR(interaction) of 7.33 (P(interaction) = 0.029).</p><p><b>CONCLUSIONS</b>In a Han Chinese population, CFH and HTRA1 polymorphisms appear to be independently and possibly additively hereditary contributors to exudative AMD. Y402H polymorphism conferred a significant but relatively lower contribution in Chinese than in Caucasians with a low frequency of risk allele. The gene-environment interaction may be a best way to encourage those with a high genetic risk to prevent AMD by avoiding modifiable factors until there is effective treatment for AMD.</p>

Hemolytic uremic syndrome / 소아과

The hemolytic uremic syndrome (HUS) is a rare disease of microangiopathic hemolytic anemia, low platelet count and renal impairment. HUS usually occurs in young children after hemorrhagic colitis by shigatoxin-producing enterohemorrhagic E. coli (D+HUS). HUS is the most common cause of acute renal failure in infants and young children, and is a substantial cause of acute mortality and morbidity; however, renal function recovers in most of them. About 10% of children with HUS do not reveal preceding diarrheal illness, and is referred to as D- HUS or atypical HUS. Atypical HUS comprises a heterogeneous group of thrombomicroangiopathy (TMA) triggered by non-enteric infection, virus, drug, malignancies, transplantation, and other underlying medical condition. Emerging data indicate dysregulation of alternative complement pathway in atypical HUS, and genetic analyses have identified mutations of several regulatory genes; i.e. the fluid phase complement regulator Factor H (CFH), the integral membrane regulator membrane cofactor protein (MCP; CD46) and the serine protease Factor I (IF). The uncontrolled activation of the complement alternative pathway results in the excessive consumption of C3. Plasma exchange or plasma infusion is recommended for treatment of, and has dropped the mortality rate. However, overall prognosis is poor, and many patients succumb to end- stage renal disease. Clinical presentations, response to plasma therapy, and outcome after renal transplantation are influenced by the genotype of the complement regulators. Thrombotic thrombocytopenic purpura (TTP), another type of TMA, occurs mainly in adults as an acquired disease accompanied by fever, neurologic deficits and renal abnormalities. However, less frequent cases of congenital or hereditary TTP associated with ADAMTS-13 (a disintegrin and metalloprotease, with thrombospondin 1-like domains 13) gene mutations have been reported, also. Recent advances in molecular genetics better allow various HUS to be distinguished on the basis of their pathogenesis. The genetic analysis of HUS is important in defining the underlying etiology, predicting the genotype-related outcome and optimizing the management of the patients.