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Age-related macular degeneration (AMD) is a progressive retinal disease that primarily affects the macula, leading to central vision loss and impaired color vision. Among its most severe forms is geographic atrophy (GA), which results in irreversible central blindness. While numerous risk factors, including age, smoking, and genetics, contribute to the development of AMD, effective treatment options for GA have been limited. This article centers on Izervay [avacincaptad pegol (ACP)], an FDA-approved drug designed to address the unmet medical needs of patients with GA secondary to AMD. The pathophysiology of GA involves oxidative damage, chronic inflammation, and cell death, primarily due to complement system dysregulation. Previous treatments for GA have shown limited efficacy, leaving patients searching for more effective solutions. Izervay, with its unique mechanism of action, inhibits complement protein C5, disrupting the formation of the membrane attack complex and slowing retinal cell degeneration. Clinical trials have demonstrated Izervay's ability to significantly reduce the growth of GA lesions, offering hope for improved outcomes. Additionally, the drug has exhibited a tolerable safety profile, with common side effects including conjunctival hemorrhage and increased intraocular pressure. Izervay represents a breakthrough in AMD treatment, offering the potential to preserve vision in those at risk of irreversible vision loss due to GA. While further research is necessary to evaluate long-term efficacy and accessibility, its approval opens new possibilities in AMD management, transforming the lives of individuals affected by this condition.
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Background: Attention deficit hyperactivity disorder (ADHD) is a widespread neuropsychiatric disorder in both children and adolescents, which is associated with social isolation and poor academic performance. Complement proteins are regarded as a major player in inflammation and disease development for several neuropsychiatric diseases such as schizophrenia and bipolar diseases. As clarified by previous data, increased levels of complement molecules and other immunological markers as cytokines were demonstrated in these disorders. Limited studies have investigated complement proteins particularly terminal complement complex or membrane attack complex (C5b-9) among ADHD patients. The present research aims to elucidate the association between C5b-9 complex protein and ADHD. Methods: This is a cross-sectional study. Sera were collected from Al-Hussain Teaching Medical City in Holy Karbala, Iraq, during 2019-2020. Sera were tested for C5-b9 using commercial kits by enzyme-linked immunosorbent assay (ELISA). Results: In 90 participants included in the study, a significant increment in C5b-9 levels among ADHD patients (P=0.019) was observed. Patients with positive C5b-9 levels had a 2.76 times higher risk of developing ADHD than control subjects. The diagnostic utility for C5b-9 was statistically significant with 71.11% sensitivity, 55.6% specificity, and a high negative predictive value (97.3%). Conclusion: The study concluded elevation of the C5b-9 terminal complements complex levels in ADHD patients, which could point to the association of complement proteins as inflammatory markers with the ADHD disease process.
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Trastorno por Déficit de Atención con Hiperactividad , Humanos , Trastorno por Déficit de Atención con Hiperactividad/sangre , Trastorno por Déficit de Atención con Hiperactividad/psicología , Niño , Masculino , Femenino , Estudios Transversales , Adolescente , Complejo de Ataque a Membrana del Sistema Complemento/análisis , Biomarcadores/sangre , Biomarcadores/análisis , IrakRESUMEN
Introduction: Neisseria meningitidis is a significant cause of bacterial meningitis and septicemia worldwide. Recurrent Neisseria meningitidis is frequently associated with terminal complement protein deficiency, including Complement component 7. This report discusses the first case of C7 deficiency in Qatar. Case report: A 30-year-old Qatari man presented with a meningococcal infection, which was verified by a blood culture. He experienced two episodes of meningitis caused by an undetermined organism. His blood tests revealed low levels of CH50 and C7. His C7 gene testing revealed a homozygous mutation in exon 10 (c.1135G>C p.Gly379Arg), a mutation that has not been previously documented in Qatar. However, it has been observed in 1% of Moroccan-origin Israeli Jews who also exhibit C7 deficiency. Regular prophylactic quadrivalent vaccinations against types A, C, Y, and W-135 with azithromycin tabs were administered. Over the last 10 years of follow-up, he remained in good health, with no further meningitis episodes. Conclusion: To our knowledge, this is the first confirmed case of C7 deficiency reported in the Arabian Gulf countries. Such rare diseases should be a public health priority. Awareness among medical practitioners and the community should help with early detection of C7 deficiency and the prevention of its consequences.
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Meningitis , Neisseria meningitidis , Masculino , Humanos , Adulto , Complemento C7/genética , Qatar , Estudios de SeguimientoRESUMEN
OBJECTIVE: We sought to determine if soluble levels of C5b-9, the terminal complement complex, correlate with end-organ injury in preeclampsia. STUDY DESIGN: Project COPA (Complement and Preeclampsia in the Americas), a multi-center observational study in Colombia from 2015 to 2016, enrolled hypertensive pregnant women into four groups: chronic hypertension, gestational hypertension, preeclampsia, and preeclampsia with severe features. Trained coordinators collected clinical data, blood and urine. End-organ injury was defined by serum creatinine ≥ 1.0 mg/dl, aspartate transaminase ≥ 70U/L, platelet count < 150,000/µl, or lactate dehydrogenase ≥ 500 U/L. Data were analyzed by χ2 or Fisher's exact test with significance at P < 0.05. MAIN OUTCOME MEASURE: C5b-9 concentrations in plasma and urine, using enzyme linked immunosorbent assays. RESULTS: In total, 298 hypertensive participants were enrolled. Plasma and urine C5b-9 levels were measured in all participants and stratified by quartile (Q1-4), from lowest to highest C5b-9 concentration. Participants with low plasma C5b-9 levels (Q1) were more likely to have end-organ injury compared to those with higher levels (Q2-Q4) [platelet count < 150,000/µl (20.8% vs. 8.4%, P = 0.01); elevated serum creatinine ≥ 1.0 mg/dl (14.9% vs. 4.5%, P = 0.009)]. In contrast, participants with high urinary C5b-9 levels (Q4) were more likely to have end-organ injury compared to those with lower levels (Q1-Q3) [platelet count < 150,000/µl (19.7% vs. 7.4%, P = 0.003); elevated serum creatinine ≥ 1.0 mg/dl (12.3% vs. 4.4%, P = 0.025)]. CONCLUSION: We identified a pattern of increased urine and low plasma C5b-9 levels in patients with preeclampsia and end-organ injury. Soluble C5b-9 levels may be used to identify complement-mediated end-organ injury in preeclampsia.
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Hipertensión , Preeclampsia , Complejo de Ataque a Membrana del Sistema Complemento/orina , Proteínas del Sistema Complemento , Creatinina , Femenino , Humanos , Hipertensión/orina , EmbarazoRESUMEN
The complement system is critical to human health owing to its central role in host defense and innate immunity. During pregnancy, the complement system must be appropriately regulated to allow for immunologic tolerance to the developing fetus and placenta. Although some degree of complement activation can be seen in normal pregnancy, the fetus seems to be protected in part through the placental expression of complement regulatory proteins, which inhibit complement activation at different steps along the complement activation cascade. In women who develop preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome, there is a shift toward increased complement activation and decreased complement regulation. There is an increase in placental deposition of C5b-9, which is the terminal effector of classical, lectin, and alternative complement pathways. C5b-9 deposition stimulates trophoblasts to secrete soluble fms-like tyrosine kinase-1, which sequesters vascular endothelial growth factor and placental growth factor. Pathogenic mutations or deletions in complement regulatory genes, which predispose to increased complement activation, have been detected in women with preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome. Before the disease, biomarkers of alternative complement pathway activation are increased; during active disease, biomarkers of terminal complement pathway activation are increased. Urinary excretion of C5b-9 is associated with preeclampsia with severe features and distinguishes it from other hypertensive disorders of pregnancy. Taken together, existing data link preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome with increased activation of the terminal complement pathway that, in some cases, may be influenced by genetic alterations in complement regulators. These findings suggest that the inhibition of the terminal complement pathway, possibly through C5 blockade, may be an effective strategy to treat preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome, but this strategy warrants further evaluation in clinical trials.
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Activación de Complemento , Síndrome HELLP/inmunología , Preeclampsia/inmunología , Anticuerpos Monoclonales Humanizados/uso terapéutico , Biomarcadores/sangre , Inactivadores del Complemento/uso terapéutico , Proteínas del Sistema Complemento/análisis , Proteínas del Sistema Complemento/genética , Femenino , Síndrome HELLP/sangre , Síndrome HELLP/tratamiento farmacológico , Humanos , Mutación , Factor de Crecimiento Placentario/sangre , Preeclampsia/sangre , Preeclampsia/tratamiento farmacológico , Embarazo , Receptor 1 de Factores de Crecimiento Endotelial Vascular/sangreRESUMEN
Transplant-associated thrombotic microangiopathy (TA-TMA) is an increasingly recognized complication of allogeneic and autologous hematopoietic cellular therapy (HCT), associated with significant morbidity and mortality. Although the central drivers of the disease are thought to be endothelial damage and complement activation, no specific diagnostic biomarkers have been identified. TA-TMA is typically diagnosed using criteria comprised of non-specific clinical and laboratory features. Some patients will have a self-remitting course, but more than half develop multi-organ dysfunction or die, making prognostic biomarkers critical. Prevention of TA-TMA, an approach central to other HCT complications such as graft-versus-host disease, is largely untested in part due to a lack of identified early high-risk biomarkers. We conducted a systematic review to summarize the diagnostic, early risk, and prognostic biomarkers of TA-TMA. We screened the titles and abstracts of 1524 citations. After screening out duplications, we read the abstracts of 979 papers and fully reviewed 132 full-text publications. Thirty-one publications fulfilled the inclusion criteria of more than five patients with TA-TMA and a reported measure of association with diagnosis, prognosis, or risk of later development of the disease. Fourteen studies (45%) were with adults, 12 (39%) were with children <18 years old, three included both children and adults, and two did not report age. There were 53 biomarker or biomarker signature entries, and a total of 27 unique biomarkers. Only four biomarkers reported sensitivity and specificity. The single biomarker with the most robust data was sC5b-9, which conferred diagnostic, prognostic, and risk implications. Studies of combinations of biomarkers were rare. No meta-analyses were performed because of significant heterogeneity between studies. The limitations of studies included small sample size, study designs with a high risk of bias (i.e., case-control), the timing of sample collection, and the selection of controls. Furthermore, only two (6%) studies included a training and validation cohort. Cut-off points are needed to stratify groups, as most biomarkers do not have normal values, or normal values cannot be assumed in the HCT setting. In the future, multi-institutional, collaborative efforts are needed to perform rigorously designed, prospective studies with serially enrolled patients, with samples collected at the time of TA-TMA diagnosis, careful selection of controls, and validation of selected biomarkers and cut-off points in a separate cohort.
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Enfermedad Injerto contra Huésped , Microangiopatías Trombóticas , Adulto , Niño , Humanos , Adolescente , Pronóstico , Estudios Prospectivos , Biomarcadores , Enfermedad Injerto contra Huésped/etiología , Microangiopatías Trombóticas/etiologíaRESUMEN
Background: Transplant-associated thrombotic microangiopathy (TA-TMA) is a serious complication of hematopoietic stem cell transplantation (HSCT) associated with high morbidity and mortality. High-risk TA-TMA (hrTA-TMA) is characterized by multifactorial endothelial damage caused by environmental stressors, dysregulation of the complement system, and genetic predisposition. Complement inhibitors have significantly decreased mortality and are the current treatment of choice. In this article, we describe our experience with the use of eculizumab in pediatric patients diagnosed with hrT-TMA after HSCT. Method: Retrospective study of pediatric patients with hrTA-TMA treated with eculizumab between January 2016 and December 2020. Results: Four pediatric patients aged 1, 12, 14, and 17 years at the time of HSCT were diagnosed with hrTA-TMA and treated with eculizumab during the study. At diagnosis, they all had renal impairment with proteinuria, and hypertension under treatment with at least two antihypertensive drugs. The patient who presented multisystemic involvement died instead of treatment. The three patients with exclusive renal involvement achieved TA-TMA resolution after treatment with eculizumab for 65, 52, and 40.6 weeks and were able to stop treatment. The two patients with follow-up data one year after eculizumab withdrawal sustained a favorable response. Eculizumab was well tolerated, and with adequate vaccination and antibiotic prophylaxis, did not increase the risk of infection. Conclusions: Eculizumab appears to be both safe and effective for the treatment of hrTA-TMA in patients with renal impairment. Early diagnosis and initiation of treatment may improve response. Eculizumab withdrawal can be contemplated in patients who achieve laboratory and clinical resolution of TA-TMA.
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BACKGROUND: Complement activation is a central mechanism in systemic inflammation and remote organ dysfunction following major trauma. Data on temporal changes of complement activation early after injury is largely missing. We aimed to describe in detail the kinetics of complement activation in individual trauma patients from admission to 10 days after injury, and the association with trauma characteristics and outcome. METHODS: In a prospective cohort of 136 trauma patients, plasma samples obtained with high time resolution (admission, 2, 4, 6, 8 h, and thereafter daily) were assessed for terminal complement complex (TCC). We studied individual TCC concentration curves and calculated a summary measure to obtain the accumulated TCC response 3 to 6 h after injury (TCC-AUC3-6). Correlation analyses and multivariable linear regression analyses were used to explore associations between individual patients' admission TCC, TCC-AUC3-6, daily TCC during the intensive care unit stay, trauma characteristics, and predefined outcome measures. RESULTS: TCC concentration curves showed great variability in temporal shapes between individuals. However, the highest values were generally seen within the first 6 h after injury, before they subsided and remained elevated throughout the intensive care unit stay. Both admission TCC and TCC-AUC3-6 correlated positively with New Injury Severity Score (Spearman's rho, p-value 0.31, 0.0003 and 0.21, 0.02) and negatively with admission Base Excess (- 0.21, 0.02 and - 0.30, 0.001). Multivariable analyses confirmed that deranged physiology was an important predictor of complement activation. For patients without major head injury, admission TCC and TCC-AUC3-6 were negatively associated with ventilator-free days. TCC-AUC3-6 outperformed admission TCC as a predictor of Sequential Organ Failure Assessment score at day 0 and 4. CONCLUSIONS: Complement activation 3 to 6 h after injury was a better predictor of prolonged mechanical ventilation and multiple organ dysfunction syndrome than admission TCC. Our data suggest that the greatest surge of complement activation is found within the first 6 h after injury, and we argue that this time period should be in focus in the design of future experimental studies and clinical trials using complement inhibitors.
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Activación de Complemento , Traumatismos Craneocerebrales/inmunología , Insuficiencia Multiorgánica/inmunología , Respiración Artificial , Heridas y Lesiones/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Complejo de Ataque a Membrana del Sistema Complemento/inmunología , Traumatismos Craneocerebrales/mortalidad , Femenino , Hospitalización , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Síndrome , Factores de Tiempo , Heridas y Lesiones/mortalidad , Adulto JovenRESUMEN
Transplantation-associated thrombotic microangiopathy (TA-TMA) is a complication of allogeneic hematopoietic cell transplantation (HCT) that often occurs following the development of acute graft-versus-host disease (aGVHD). In this study, we aimed to identify early TMA biomarkers among patients with aGVHD. We performed a nested-case-control study from a prospective cohort of allogeneic HCT recipients, matching on the timing and severity of antecedent aGVHD. We identified 13 TMA cases and 25 non-TMA controls from 208 patients in the cohort. Using multivariable conditional logistic regression, the odds ratio for TMA compared with non-TMA was 2.65 (95% confidence interval [CI], 1.00 to 7.04) for every 100 ng/mL increase in terminal complement complex sC5b9 and 2.62 (95% CI, 1.56 to 4.38) for every 1000 pg/mL increase in angiopoietin-2 (ANG2) at the onset of aGVHD. ADAMTS13 and von Willebrand factor (VWF) antigens were not appreciably associated with TMA. Using a Cox regression model incorporating sC5b9 >300 ng/mL and ANG2 >3000 pg/mL at the onset of aGVHD, the adjusted hazard ratio for mortality was 5.33 (95% CI, 1.57 to 18.03) for the high-risk group (both elevated) and 4.40 (95% CI, 1.60 to 12.07) for the intermediate-risk group (one elevated) compared with the low-risk group (neither elevated). In conclusion, we found that elevated sC5b9 and ANG2 levels at the onset of aGVHD were associated with the development of TMA and possibly mortality after accounting for the timing and severity of aGVHD. The results suggest important roles of complement activation and endothelial dysfunction in the pathogenesis of TMA. Measurement of these biomarkers at the onset of aGVHD may inform prognostic enrichment for preventive trials and improve clinical care.
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Enfermedad Injerto contra Huésped , Microangiopatías Trombóticas , Biomarcadores , Estudios de Casos y Controles , Enfermedad Injerto contra Huésped/diagnóstico , Humanos , Pronóstico , Estudios Prospectivos , Microangiopatías Trombóticas/diagnósticoRESUMEN
BACKGROUND AND OBJECTIVES: Atypical hemolytic uremic syndrome is a form of thrombotic microangiopathy caused by dysregulation of the alternative complement pathway. There is evidence showing complement activation in other thrombotic microangiopathies. The aim of this study was to evaluate complement activation in different thrombotic microangiopathies and to monitor treatment response. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Complement activation was assessed by exposing endothelial cells to sera or activated-patient plasma-citrated plasma mixed with a control sera pool (1:1)-to analyze C5b-9 deposits by immunofluorescence. Patients with atypical hemolytic uremic syndrome (n=34) at different stages of the disease, HELLP syndrome (a pregnancy complication characterized by hemolysis, elevated liver enzymes, and low platelet count) or severe preeclampsia (n=10), and malignant hypertension (n=5) were included. RESULTS: Acute phase atypical hemolytic uremic syndrome-activated plasma induced an increased C5b-9 deposition on endothelial cells. Standard and lower doses of eculizumab inhibited C5b-9 deposition in all patients with atypical hemolytic uremic syndrome, except in two who showed partial remission and clinical relapse. Significant fibrin formation was observed together with C5b-9 deposition. Results obtained using activated-plasma samples were more marked and reproducible than those obtained with sera. C5b-9 deposition was also increased with samples from patients with HELLP (all cases) and preeclampsia (90%) at disease onset. This increase was sustained in those with HELLP after 40 days, and levels normalized in patients with both HELLP and preeclampsia after 6-9 months. Complement activation in those with malignant hypertension was at control levels. CONCLUSIONS: The proposed methodology identifies complement overactivation in patients with atypical hemolytic uremic syndrome at acute phase and in other diseases such as HELLP syndrome and preeclampsia. Moreover, it is sensitive enough to individually assess the efficiency of the C5 inhibition treatment.
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Activación de Complemento , Microangiopatías Trombóticas/inmunología , Adulto , Anticuerpos Monoclonales Humanizados/uso terapéutico , Síndrome Hemolítico Urémico Atípico/tratamiento farmacológico , Síndrome Hemolítico Urémico Atípico/inmunología , Complejo de Ataque a Membrana del Sistema Complemento/metabolismo , Femenino , Síndrome HELLP/inmunología , Humanos , Masculino , Preeclampsia/tratamiento farmacológico , Preeclampsia/inmunología , Embarazo , Microangiopatías Trombóticas/tratamiento farmacológicoRESUMEN
INTRODUCTION: The molecular mechanism of immune-mediated necrotizing myopathy (IMNM) remains unknown. Autophagy impairment, described in autoimmune diseases, is a key process in myofiber protein degradation flux and muscle integrity and has not been studied in IMNM. METHODS: Muscle biopsies from patients with IMNM (n = 40), dermatomyositis (DM; 24), polymyositis (PM; 8), polymyositis with mitochondrial pathology (4), sporadic inclusion body myositis (8), and controls (6) were compared by immunohistochemistry. RESULTS: The proportions of myofibers containing autophagy markers LC3b and p62 were higher in IMNM than in DM or PM and correlated with creatine kinase levels. In IMNM, compartmentalized LC3b puncta were located in regenerating and degenerating myofibers surrounded by major histocompatibility complex type II+ inflammatory cells. Several IMNM myofibers accumulated ubiquitin and misfolded protein. DISCUSSION: The detection of LC3b+ or p62+ myofibers could be used in differentiating IMNM from PM. The identification of autophagy-modifying molecules potentially could improve patients' outcomes. Muscle Nerve, 2019.
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Autofagia/inmunología , Músculo Esquelético/patología , Miositis/inmunología , Miositis/patología , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/patología , Biopsia , Dermatomiositis/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Miositis por Cuerpos de Inclusión/patología , Polimiositis/inmunología , Polimiositis/patologíaRESUMEN
RATIONALE & OBJECTIVE: Primary membranoproliferative glomerulonephritis (MPGN) is a rare glomerulopathy characterized by complement dysregulation. MPGN progresses rapidly to kidney failure when it is associated with nephrotic syndrome. We assessed the effects of C5 convertase blockade in patients with MPGN and terminal complement activation. STUDY DESIGN: Prospective off-on-off-on open-label clinical trial. SETTING & PARTICIPANTS: Consenting patients with immune complex-mediated MPGN (n=6) or C3 glomerulonephritis (n=4) with sC5b-9 (serum complement membrane attack complex) plasma levels>1,000ng/mL and 24-hour proteinuria with protein excretion>3.5g identified from the Italian Registry of MPGN and followed up at the Istituto di Ricerche Farmacologiche Mario Negri IRCCS (Bergamo, Italy) between March 4, 2014, and January 7, 2015. INTERVENTION: Anti-C5 monoclonal antibody eculizumab administered during 2 sequential 48-week treatment periods separated by one 12-week washout period. OUTCOMES: Primary outcome was change in 24-hour proteinuria (median of 3 consecutive measurements) at 24 and 48 weeks. RESULTS: Median proteinuria decreased from protein excretion of 6.03 (interquartile range [IQR], 4.8-12.4) g/d at baseline to 3.74 (IQR, 3.2-4.4) g/d at 24 weeks (P=0.01) and to 5.06 (IQR, 3.1-5.8) g/d (P=0.006) at 48 weeks of treatment, recovered toward baseline during the washout period, and did not significantly decrease thereafter. Hypoalbuminemia, dyslipidemia, and glomerular sieving function improved during the first treatment period. 3 patients achieved partial remission of nephrotic syndrome and all had undetectable C3 nephritic factors before treatment. Mean measured glomerular filtration rate was 69.7±35.2 versus 87.4±55.1 and 75.8±42.7 versus 76.6±44.1mL/min/1.73m2 at the start versus the end of the first and second treatment periods, respectively, among all 10 study participants. Unlike C3, sC5b-9 plasma levels normalized during both treatment periods and recovered toward baseline during the washout in all patients. LIMITATIONS: Single-arm design, small sample size. CONCLUSIONS: Eculizumab blunted terminal complement activation in all patients with immune complex-mediated MPGN or C3 glomerulonephritis and nephrotic syndrome, but persistently reduced proteinuria in just a subgroup. TRIAL REGISTRATION: Registered in the EU Clinical Trials Register with study no. 2013-003826-10.
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Anticuerpos Monoclonales Humanizados/farmacología , Anticuerpos Monoclonales Humanizados/uso terapéutico , Activación de Complemento/efectos de los fármacos , Convertasas de Complemento C3-C5/antagonistas & inhibidores , Inactivadores del Complemento/farmacología , Inactivadores del Complemento/uso terapéutico , Glomerulonefritis Membranoproliferativa/tratamiento farmacológico , Glomerulonefritis Membranoproliferativa/inmunología , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Estudios Prospectivos , Adulto JovenRESUMEN
PROBLEM: Crry is a widely expressed type 1 transmembrane complement regulatory protein in rodents which protects self-tissue by downregulating C3 activation. Crry-/- concepti produced by Crry+/- × Crry+/- matings are attacked by maternal complement system leading to loss before day 10. The membrane attack complex is not the mediator of this death. We hypothesized that the ability of C3b to engage the alternative pathway's feedback loop relatively unchecked on placental membranes induces the lesion yielding the demise of the Crry-/- mouse. METHOD OF STUDY: We investigated the basis of Crry-/- conceptus demise by depleting maternal complement with cobra venom factor and blocking antibodies. We monitored their effects primarily by genotyping and histologic analyses. RESULTS: We narrowed the critical period of the complement effect from 6.5 to 8.5 days post-coitus (dpc), which is immediately after the conceptus is exposed to maternal blood. Deposition by 5.5 dpc of maternal C3b on the placental vasculature lacking Crry-/- yielded loss of the conceptus by 8.5 dpc. Fusion of the allantois to the chorion during placental assembly did not occur, fetal vessels originating in the allantois did not infiltrate the chorioallantoic placenta, the chorionic plate failed to develop, and the labyrinthine component of the placenta did not mature. CONCLUSION: Our data are most consistent with the deposition of C3b being responsible for the failure of the allantois to fuse to the chorion leading to subsequent conceptus demise.
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Aborto Espontáneo/genética , Activación de Complemento/inmunología , Complemento C3b/inmunología , Vía Alternativa del Complemento/inmunología , Embrión de Mamíferos/patología , Receptores de Complemento/genética , Aborto Espontáneo/inmunología , Animales , Convertasas de Complemento C3-C5 de la Vía Alternativa/metabolismo , Embrión de Mamíferos/inmunología , Femenino , Ratones , Ratones Noqueados , Placenta/inmunología , Placenta/patología , Embarazo , Receptores de Complemento 3bRESUMEN
BACKGROUND AND OBJECTIVES: C3 glomerulopathy is a form of complement-mediated GN. Immunosuppressive therapy may be beneficial in the treatment of C3 glomerulopathy. Mycophenolate mofetil is an attractive treatment option given its role in the treatment of other complement-mediated diseases and the results of the Spanish Group for the Study of Glomerular Diseases C3 Study. Here, we study the outcomes of patients with C3 glomerulopathy treated with steroids and mycophenolate mofetil. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a retrospective chart review of patients in the C3 glomerulopathy registry at Columbia University and identified patients treated with mycophenolate mofetil for at least 3 months and follow-up for at least 1 year. We studied clinical, histologic, and genetic data for the whole group and compared data for those who achieved complete or partial remission (responders) with those who did not achieve remission (nonresponders). We compared remission with mycophenolate mofetil with remission with other immunosuppressive regimens. RESULTS: We identified 30 patients who met inclusion criteria. Median age was 25 years old (interquartile range, 18-36), median creatinine was 1.07 mg/dl (interquartile range, 0.79-1.69), and median proteinuria was 3200 mg/g creatinine (interquartile range, 1720-6759). The median follow-up time was 32 months (interquartile range, 21-68). Twenty (67%) patients were classified as responders. There were no significant differences in baseline characteristics between responders and nonresponders, although initial proteinuria was lower (median 2468 mg/g creatinine) in responders compared with nonresponders (median 5000 mg/g creatinine) and soluble membrane attack complex levels were higher in responders compared with nonresponders. For those tapered off mycophenolate mofetil, relapse rate was 50%. Genome-wide analysis on complement genes was done, and in 12 patients, we found 18 variants predicted to be damaging. None of these variants were previously reported to be pathogenic. Mycophenolate mofetil with steroids outperformed other immunosuppressive regimens. CONCLUSIONS: Among patients who tolerated mycophenolate mofetil, combination therapy with steroids induced remission in 67% of this cohort. Heavier proteinuria at the start of therapy and lower soluble membrane attack complex levels were associated with treatment resistance.
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Antiinflamatorios/uso terapéutico , Complemento C3/inmunología , Glomerulonefritis Membranoproliferativa/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Ácido Micofenólico/uso terapéutico , Prednisona/uso terapéutico , Adolescente , Adulto , Complemento C3/genética , Complemento C3/metabolismo , Creatinina/sangre , Quimioterapia Combinada , Femenino , Glomerulonefritis Membranoproliferativa/etiología , Humanos , Masculino , Proteinuria/etiología , Estudios Retrospectivos , Resultado del Tratamiento , Secuenciación del Exoma , Adulto JovenRESUMEN
Objective Studies are rarely reported on how to avoid complement system attack during the transplantation of bone marrow mesenchymal stem cells (BMSCs).We explored the effect of the overexpression of CD59 on complement membrane attack-induced damage to rat BMSCs (rBMSCs) during autologous transplantation.Methods BMSCs from SD rats were cultured and treated with CD59 overexpression plasmid or rBMSC empty vector or left untreated,followed by detection of the expression of CD59 in the rBMSCs by flow cytometry.Then the rBMSCs were incubated with autologous rat serum (ARS),inactivated ARS (iARS),CD59+ARS,or CD59+iARS or not incubated.The cytotoxicity of the serum complement on the rBMSCs was observed by PI staining and the apoptosis of the rBMSCs determined by flow cytometry.Results The expression of CD59 was significantly higher in the rBMSCs treated with CD59 than in those untreated (7,4.9％ vs 50.5％,P＜0.05).The apop tosis rate was remarkably lower in the rBMSCs not incubated ([8.4± 1.1] ％) and those incubated with CD59+ARS ([19.1 ±3.1] ％) than in those incubated with ARS ([40.3±4.3] ％) (P＜0.05).The deposition of the complement membrane attack complex was significantly decreased in the rBMSCs not incubated (50.1％) and those incubated with CD59+ARS (71.0％) as compared with those incubated with ARS (99.7％) (P＜0.05).The apoptosis rate of the rBMSCs treated with CD59 was markedly lower than that of those left untreated (P＜0.05).Conclusion The overexpression of CD59 inhibits the damage induced by complement to rBMSCs by reducing the formation of the complement membrane attack complex during autologous transplantation.
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Objective To explore the effect of complement activation on bone marrow mesenchymal stem cells (BMSCs)and evaluate the effect after transfection of complement regulatory proteins.Methods Bone marrow aspirate was harvested from 10 cases of patients suffered from fractures.Mesenchymal stem ceils were isolated,indentified cultured and then experimented in vitro.The complement cytotoxicity on the mesenchymal stem cells in autologous serum was measured by Europium cytotoxicity assay.The samples were divided into BMSCs group,BMSCs+ autologous human serum (AHS) group and BMSCs+ inactivated autologous human serum (iAHS) group.The complement membrane attack complex (MAC) deposited on the membranes was detected by flow cytometry.Finally,the cytotoxicity on BMSCs was measured after transfected with membrane complement regulatory proteins (mCRPs).All samples were divided into BMSCs with mCRPs untransfected group and BMSCs with mCRPs transfected group.Results More than 95％ of cells derived from bone marrow were identified to be mesenchymal stem cells through detection of cell surface markers by flow cytometry.The cytotoxicity of untreated cells was 0.41％± 1.48％.BMSCs harvested from the 10 patients all had cytotoxicity after incubated with autologous serum,and the cytotoxicity was 32.59％±2.73％,while cytotoxicity after incubated with complement inactivated autologous serum was 2.59％±3.08％,which was similar to control group.Complement attack complex (MAC) could be detected on the BMSCs incubated with autologous serum,which implied the complement activation.After transfection of mCRPs,the cytotoxicity of autologous serum on transfected cells was decreased.The cytotoxicity of untransfected cells (41.70％±4.47％) had significant difference compared to the cells transfected with CD55 (21.87％±2.19％),the cells transfected with CD59 (18.67％± 1.42％),and the cells transfected with CD46+CD55+CD59 (28.43％±2.14％).CD55,CD59 and CD46+CD55 +CD59 transfected groups could impair effectively the cytotoxicity from complement.However,the cytotoxicity impairment was less effective in CD46 transfected cells (39.30％±3.96％),which had no significant difference compared to untransfected cells.Conclusion Membrane complement regulatory proteins could effectively protect bone marrow mesenchymal stem cells from attacks by complement.
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Objective To describe the clinical and muscle pathological characters of juvenile myositis patients with perifascicular atrophy (PFA).Methods A series of 21 consecutive muscle biopsies with clinically and pathologically confirmed juvenile myositis were studied.All biopsies had PFA of muscle fibers.Results Clinical manifestation:11/21 had typical dermatomyositis rash,9/21 possible dermatomyositis because of atypical rash,1/21 mixed connective tissue disease;9/21 had weakness complaint;9/21with normal creatine kinase (CK) level,4/21 low grade rise,8/21 apparently elevated,10/ 11 definite dermatomyositis patients with normal or low grade level;6/21 combined with interstitial lung disease,2 with EB virus infection,1 with cytomegalo virus infection.Muscle pathology:4 specimens with atypical PFA also had enzyme abnormality in nicotinamide adenine dinucleotide,succinate dehydrogenase and cytochrome c oxidase staining,9/12 cases had membrane attack complement deposition intramuscular capillaries,and they had prominent regional mitochondrial abnormalities,protrude PFA and focal muscle damage.Skin biopsy of one case showed perivasculitis in dermis.Conclusions PFA could be seen in juvenile dermatomyositis and mixed connective tissue disease,and PFA could not increase the CK level.The capillary and intermediate-sized vessels damage may cause chronic ischemia,which could explain the PFA with mitochondrial abnormalities.
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This study is to investigate the expression of complement membrane attack complex (C5b-9) in the skeletal muscle of patients with necrotizing myopathy (NM), and to investigate the relationship between C5b-9 and NM. Thirteen patients with NM and control patients with polymyositis and muscular dystrophy were enrolled in this study. Examinations including creatine kinase (CK) and L-lactate dehydrogenase (LDH) in the serum, electromyogram and muscle pathological examination were performed. C5b-9 expression in the skeletal muscle was determined by immunohistochemistry and analyzed by Image Plus Pro 6.0. C5b-9 expression was particularly prominent in necrotic muscle fibers, and also positive in blood vessels. C5b-9 diffusely expressed in vascular endothelial cells and smooth muscle layer. But the intensity was not related with the elevated level of serum CK. So, C5b-9 is strongly expressed in the necrotic muscle fiber and blood vessels, and may contribute to the pathogenesis of NM.
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Complejo de Ataque a Membrana del Sistema Complemento/inmunología , Músculo Esquelético/patología , Enfermedades Musculares/inmunología , Enfermedades Musculares/patología , Adolescente , Adulto , Anciano , Niño , Complejo de Ataque a Membrana del Sistema Complemento/análisis , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Músculo Esquelético/inmunología , Necrosis , Adulto JovenRESUMEN
Kidney injury with proteinuria is a characteristic feature of preeclampsia, yet the nature of injury in specific regions of the nephron is incompletely understood. Our study aimed to use existing urinary biomarkers to describe the pattern of kidney injury and proteinuria in pregnancies affected by severe preeclampsia. We performed a case-control study of pregnant women from Brigham and Women's Hospital from 2012 to 2013. We matched cases of severe preeclampsia (n=25) 1:1 by parity and gestational age to 2 control groups with and without chronic hypertension. Urinary levels of kidney injury molecule-1 and complement components (C3a, C5a, and C5b-9) were measured by enzyme-linked immunosorbent assay, and other markers (albumin, ß2 microglobulin, cystatin C, epithelial growth factor, neutrophil gelatinase-associated lipocalin, osteopontin, and uromodulin) were measured simultaneously with a multiplex electrochemiluminescence assay. Median values between groups were compared with the Wilcoxon signed-rank test and correlations with Spearman correlation coefficient. Analysis of urinary markers revealed higher excretion of albumin and kidney injury molecule-1 and lower excretion of neutrophil gelatinase-associated lipocalin and epithelial growth factor in severe preeclampsia compared with chronic hypertension and healthy controls. Among subjects with severe preeclampsia, urinary excretion of complement activation products correlated most closely with kidney injury molecule-1, a specific marker of proximal tubule injury (C5a: r=0.60; P=0.001; and C5b-9: r=0.75; P<0.0001). Taken together, we describe a pattern of kidney injury in severe preeclampsia that is characterized by glomerular impairment and complement-mediated inflammation and injury, possibly localized to the proximal tubule in association with kidney injury molecule-1.
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Activación de Complemento/inmunología , Túbulos Renales Proximales/inmunología , Glicoproteínas de Membrana/inmunología , Preeclampsia/inmunología , Receptores Virales/inmunología , Proteínas de Fase Aguda/inmunología , Proteínas de Fase Aguda/orina , Adulto , Albuminuria/inmunología , Albuminuria/orina , Biomarcadores/orina , Estudios de Casos y Controles , Complemento C3a/inmunología , Complemento C3a/orina , Complemento C5a/inmunología , Complemento C5a/orina , Complejo de Ataque a Membrana del Sistema Complemento/inmunología , Complejo de Ataque a Membrana del Sistema Complemento/orina , Factor de Crecimiento Epidérmico/inmunología , Factor de Crecimiento Epidérmico/orina , Femenino , Receptor Celular 1 del Virus de la Hepatitis A , Humanos , Túbulos Renales Proximales/lesiones , Lipocalina 2 , Lipocalinas/inmunología , Lipocalinas/orina , Glicoproteínas de Membrana/orina , Osteopontina/inmunología , Osteopontina/orina , Preeclampsia/patología , Preeclampsia/orina , Embarazo , Proteínas Proto-Oncogénicas/inmunología , Proteínas Proto-Oncogénicas/orina , Índice de Severidad de la Enfermedad , Uromodulina/inmunología , Uromodulina/orina , Microglobulina beta-2/inmunología , Microglobulina beta-2/orinaRESUMEN
The membrane attack complex of complement (MAC), apart from its classical role of lysing cells, can also trigger a range of non-lethal effects on cells, acting as a drive to inflammation. In the present study, we chose to investigate these non-lethal effects on inflammasome activation. We found that, following sublytic MAC attack, there is increased cytosolic Ca(2+) concentration, at least partly through Ca(2+) release from the endoplasmic reticulum lumen via the inositol 1,4,5-triphosphate receptor (IP3R) and ryanodine receptor (RyR) channels. This increase in intracellular Ca(2+) concentration leads to Ca(2+) accumulation in the mitochondrial matrix via the 'mitochondrial calcium uniporter' (MCU), and loss of mitochondrial transmembrane potential, triggering NLRP3 inflammasome activation and IL-1ß release. NLRP3 co-localises with the mitochondria, probably sensing the increase in calcium and the resultant mitochondrial dysfunction, leading to caspase activation and apoptosis. This is the first study that links non-lethal effects of sublytic MAC attack with inflammasome activation and provides a mechanism by which sublytic MAC can drive inflammation and apoptosis.