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.

Pathology of C3 Glomerulopathy

C3 glomerulopathy is a renal disorder involving dysregulation of alternative pathway complement activation. In most instances, a membranoproliferative pattern of glomerular injury with a prevalence of C3 deposition is observed by immunofluorescence microscopy. Dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) are subclasses of C3 glomerulopathy that are distinguishable by electron microscopy. Highly electron-dense transformation of glomerular basement membrane is characteristic of DDD. C3GN should be differentiated from post-infectious glomerulonephritis and other immune complex-mediated glomerulonephritides showing C3 deposits.

Effectiveness of Cyclosporine in a 10-year-old Girl with C3 Glomerulopathy

C3 glomerulopathy (C3G) is a recently defined pathological entity characterized by C3 accumulation with absent or scant immunoglobulin deposition, leading to variable glomerular inflammation. The clinical presentation of patients with C3G is highly variable, as they may present with symptoms ranging from microscopic or mild proteinuria to full-blown nephrotic syndrome, with or without renal impairment. However, there is no consensus recommendation for specific treatment in children with C3G. Recently, new therapies have been suggested to target complement pathways, owing to an improvement in the understanding of the pathogenesis of C3G. C3G complement blockade with eculizumab, a monoclonal antibody targeted against complement C5, inhibits activation of the alternative complement pathway. We could not use eculizumab owing to its high price; thus, we administered oral prednisolone and mycophenolate mofetil (MMF). MMF was replaced with cyclosporine because proteinuria persisted, with a consistently low serum C3 level; we tapered off the prednisolone because of a Cushingoid appearance and amenorrhea. Thereafter, proteinuria improved, and the serum C3 level returned to normal. Thus, we report the effectiveness of cyclosporine in a patient with C3G and an inadequate response to prednisolone and MMF, who was detected via school urinary screening.

Gut-residing Microbes Alter the Host Susceptibility to Autoantibody-mediated Arthritis

K/BxN serum can transfer arthritis to normal mice owing to the abundant autoantibodies it contains, which trigger innate inflammatory cascades in joints. Little is known about whether gut-residing microbes affect host susceptibility to autoantibody-mediated arthritis. To address this, we fed C57BL/6 mice with water containing a mixture of antibiotics (ampicillin, vancomycin, neomycin, and metronidazol) for 2 weeks and then injected them with K/BxN serum. Antibiotic treatment significantly reduced the amount of bacterial genomic DNA isolated from fecal samples, in particular a gene encoding 16S ribosomal RNA derived from segmented filamentous bacteria. Arthritic signs, as indicated by the arthritic index and ankle thickness, were significantly attenuated in antibiotic-treated mice compared with untreated controls. Peyer's patches and mesenteric lymph nodes from antibiotic-treated mice contained fewer IL-17-expressing cells than those from untreated mice. Antibiotic treatment reduced serum C3 deposition in vitro via the alternative complement pathway. IL-17-/- congenic C57BL/6 mice were less susceptible to K/BxN serum-transferred arthritis than their wild-type littermates, but were still responsive to treatment with antibiotics. These results suggest that gut-residing microbes, including segmented filamentous bacteria, induce IL-17 production in GALT and complement activation via the alternative complement pathway, which cause the host to be more susceptible to autoantibody-mediated arthritis.

Pathology of C3 Glomerulonephritis

C3 glomerulonephritis (C3GN) is a recently described entity that shows a glomerulonephritis on light microscopy, bright C3 staining and the absence of C1q, C4, and immunoglobulins on immunofluorescence microscopy and mesangial and/or subendothelial electron-dense deposits on electron microscopy. The term 'C3 glomerulopathy' is often used to include C3GN and dense deposit disease (DDD), CFHR5 nephropathy, those of which result from dysregulation of the alternative pathway of complement. C3GN shares some aspects of atypical hemolytic uremic syndrome, MPGN, late stage of post infectious glomerulonephritis and other glomerulonephrtis. When C3GN is considered, measurement of serum complement proteins including C3, CFH, CFI, CFB and testing for the presence of C3 nephritic factor, anti-factor H autoantibodies are necessary. To screening for mutations, genes that encode complement regulators should be evaluated. This disorder equally affected all ages, both genders, and typically presented with hematuria and proteinuria. In both the short and long term, renal function remained stable in the majority of patients.

Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

Evaluating the activity of the complement system under conditions of altered thyroid hormone levels might help elucidate the role of complement in triggering autoimmune processes. Here, we investigated alternative pathway (AP) activity in male Wistar rats (180 ± 10 g) after altering their thyroid hormone levels by treatment with triiodothyronine (T3), propylthiouracil (PTU) or thyroidectomy. T3 and thyroxine (T4) levels were determined by chemiluminescence assays. Hemolytic assays were performed to evaluate the lytic activity of the AP. Factor B activity was evaluated using factor B-deficient serum. An anti-human factor B antibody was used to measure factor B levels in serum by radial immunodiffusion. T3 measurements in thyroidectomized animals or animals treated with PTU demonstrated a significant reduction in hormone levels compared to control. The results showed a reduction in AP lytic activity in rats treated with increasing amounts of T3 (1, 10, or 50 µg). Factor B activity was also decreased in the sera of hyperthyroid rats treated with 1 to 50 µg T3. Additionally, treating rats with 25 µg T3 significantly increased factor B levels in their sera (P < 0.01). In contrast, increased factor B concentration and activity (32 percent) were observed in hypothyroid rats. We conclude that alterations in thyroid hormone levels affect the activity of the AP and factor B, which may in turn affect the roles of AP and factor B in antibody production.

New approaches and potential treatments for dry age-related macular degeneration / Novas abordagens e tratamentos potenciais da forma seca da degeneração macular relacionada à idade

Emerging treatments for dry age-related macular degeneration (AMD) and geographi c atrophy focus on two strategies that target components involved in physiopathological pathways: prevention of photoreceptors and retinal pigment epithelium loss (neuroprotection induction, oxidative damage prevention, and visual cycle modification) and suppression of inflammation. Neuroprotective drugs, such as ciliary neurotrophic factor, brimonidine tartrate, tandospirone, and anti-amyloid β antibodies, aim to prevent apoptosis of retinal cells. Oxidative stress and depletion of essential micronutrients are targeted by the Age-Related Eye Disease Study (AREDS) formulation. Visual cycle modulators reduce the activity of the photoreceptors and retinal accumulation of toxic fluorophores and lipofuscin. Eyes with dry age-related macular degeneration present chronic inflammation and potential treatments include corticosteroid and complement inhibition. We review the current concepts and rationale of dry age-related macular degeneration treatment that will most likely include a combination of drugs targeting different pathways involved in the development and progression of age-related macular degeneration.

Os novos tratamentos para a forma seca da degeneração macular relacionada à idade (DMRI) e da atrofia geográfica têm sido baseados em duas estratégias que abordam componentes envolvidos nos mecanismos fisiopatológicos da doença: prevenção da perda de fotorreceptores e células do epitélio pigmentado da retina (indução de neuroproteção, diminuição do dano oxidativo e modificação do ciclo visual) e supressão da inflamação. As drogas neuroprotetoras visam evitar a apoptose das células retinianas, como o fator neurotrófico ciliar, o tartarato de brimonidina, a tandosporina e anticorpos antiamiloide β. A redução do dano oxidativo e a complementação de micronutrientes essenciais são os objetivos da fórmula AREDS. Os modificadores do ciclo visual reduzem a atividade dos fotorreceptores e o acúmulo de fluoróforos tóxicos e lipofuscina na retina. Olhos com a forma seca da degeneração macular relacionada à idade apresentam inflamação crônica e os novos tratamentos incluem corticosteroides e inibidores do sistema complemento. Neste artigo, revisamos o estágio atual do tratamento da forma seca da degeneração macular relacionada à idade que provavelmente será feito através da combinação de drogas que agem em diferentes componentes envolvidos no aparecimento e na progressão da degeneração macular relacionada à idade.

Biología comparada del sistema de complemento en peces / Comparative biology of the complement system in fish / Biologia comparativa do sistema complemento em peixes

Dentro de la respuesta inmune humoral se encuentran componentes que mantienen la homeostasis de los organismos a través del control de agentes patógenos por medio de la opsonización, quimiotaxis de células fagocíticas facilitando el proceso de eliminación de lo extraño o sin su acompañamiento, en el caso de la formación de poros en la membrana celular. A un grupo de este conjunto de componentes de origen molecular proteico se denominósistema del complemento, el cual posee tres vías de activación (Clásica, Alternativa y Lectinas), funciona comoanafilatoxinas, reguladores y receptores. La presente revisión tiene como objetivo discutir acerca de los diferentes componentes del sistema del complemento en la escala animal enfocándose principalmente en peces teleósteos y mamíferos, como organismos modelos en busca de elucidar sus diferencias, homologías y respuestas.

Within the humoral immune response can be found components that maintain an organism’s homeostasis viacontrol of pathogenic agents using opsonization, chemotaxis of phagocytic cells which facilitates the processof elimination of foreign bodies, or in its absence, the formation of pores in the cellular membrane. One of these groups of components, of protein origin, is referred to as the complement system, which has 3 means of activation (Classic, Alternative, and Lectins) and functions as anaphylactic toxins, regulators and receptors. The aim of this review is to discuss the different components of the complement system in the animal kingdom, focusing principally on teleost fish and mammals, as model organisms in the search to elucidate their differences, homologies, and answers.

Dentro da resposta imune humoral encontram-se componentes que mantém a homeostase do organismo através docontrole de patógenos, por opsonização, quimiotaxia de células fagocíticas que facilita o processo de eliminaçãode corpos estranhos, ou na sua ausência, a formação de poros na membrana celular. Este conjunto de componentes moleculares de origem protéica são chamados de sistema complemento, que tem três vias de ativação (clássica, alternativa e lectinas), funciona como anafilatoxinas, reguladores e receptores. Esta revisão tem como objetivo discutir os vários componentes do sistema complemento na escala animal focando principalmente em peixes teleósteos e mamíferos como organismos modelos na busca de elucidar suas diferenças, homologias e respostas.

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.

Deficiencias de los componentes de las vías de activación clásica y alternativa del sistema del complemento / Deficiencies of the components of the classic and alternative activation pathways of the complement system

Las deficiencias congénitas de los componentes individuales de las vías clásica y alternativa del sistema del complemento, dan lugar a un conjunto de enfermedades de frecuencia relativamente baja. Las personas con deficiencias en estas funciones muestran una susceptibilidad elevada a las infecciones piógenas recurrentes por microorganismos que habitualmente son eliminados por fagocitosis y, en algunos casos, se asocian con enfermedades autoinmunes. Cuando las deficiencias del complemento comprometen la formación del complejo de ataque a la membrana, asociado con la lisis de las bacterias fuera de los fagocitos, los pacientes también tienen aumentado el riesgo de infectarse con Neisseria . Se describen las características clínicas y moleculares que caracterizan a los defectos presentes en los componentes de las vías de activación clásica y alternativa del sistema del complemento

Complement levels in Brazilian children during and after meningococcal meningitis

OBJETIVO: Avaliar a atividade funcional das vias clássica e alternativa do sistema complemento e os níveis de C3, C4 e fator B durante o primeiro episódio de infecção meningocócica e durante a convalescença. PACIENTES E MÉTODOS: Dez crianças brasileiras com idades entre 8 meses e 8 anos, admitidas de 1991 a 1993, com diagnóstico clínico-laboratorial de meningite meningocócica, foram estudadas durante infecção aguda (até 7 dias do diagnóstico) e no período de convalescença (entre 1 e 6 meses após). C3, C4 e fator B foram quantificados por nefelometria e a atividade lítica das vias clássica e alternativa foi avaliada por método cinético e expressa como tempo necessário para lisar 50% de uma suspensão de eritrócitos (T1/2, expresso em segundos). Baixos valores de T1/2 das vias clássica e alternativa se correlacionam com elevadas atividades de via clássica e via alternativa, respectivamente. RESULTADOS: Observaram-se diferenças significativas entre a atividade lítica da via alternativa durante a infecção e no período de convalescença (282 e 238 segundos, respectivamente, P= .01). Nenhuma diferença foi detectada nos outros parâmetros analisados. CONCLUSÕES: Na presença de meningite meningocócica a via alternativa é preferencialmente ativada, provavelmente devido à maior capacidade da endotoxina meningocócica para ativar esta via, in vivo.

Conceitos atuais na ativação do sistema complemento e suas propriedades biológica / Recent concepts in the activation of complement system and biological properties

O sistema complemento é formado por aproximadamente 35 proteínas e glicoproteínas distribuídas no plasma, outros líquidos biológicos e superfícies celulares. Essas proteínas atuam em uma reação sequencial em cascata e representam um dos principais mediadores da defesa inata do hospedeiro e da inflamação. A ativação do sistema complemento tanto pode ser benéfica para o hospedeiro, como na resistência a microrganismos invasores, como pode ser deletéria em uma variedade de doenças imunopatologicamente mediadas. O complemento pode ser ativado por qualquer das três vias, a via clássica, dependente do anticorpo, a via alternativa ou a recém-descrita, via das lectinas (MBL). As consequências biológicas da ativação do complemento são principalmente a defesa contra infecções piogênicas, a interação entre imunidade inata e adaptativa e a remoção de complexos-imunes e produtos da injúria tecidual. O complemento reconhece, opsoniza ou lisa partículas, incluindo bactérias, leveduras e outros microrganismo, restos celulares e células alteradas do hospedeiro. Há também evidências de que o complemento contribui significativamente na regulação da resposta imune. O principal objetivo da presente é revisão é fornecer uma visão atual da ativação e das propriedades biológicas desse sistema, enfatizando sua importãncia na resposta imune inata e na homeostasia do hospedeiro.

Alteraciones de la solubilización e inhibición de la precipitación / de inmunocomplejos en la anemia drepanocítica / Alterations of the solubilization and inhibition of the precipitation of immunocomplexes in sickle cell anemia

Se estudiaron los fenómenos de solubilización e inhibición de la precipitación de inmunocomplejos en un grupo de 39 pacientes con anemia drepanocítica en crisis hepática (13) y en estado basal (26), utilizando como modelo el complejo125 I-toxoide tetánico/anti-toxoide tetánico. La inhibición de la precipitación estuvo disminuida en la crisis hepática y en el estado basal, con valores normales de la actividad hemolítica de la vía clásica y de los niveles séricos del C4, mientras que la disminución de la solubilización en la crisis hepática estuvo relacionada con una disminución de la actividad hemolítica de la vía alternativa, la actividad hemolítica del factor B y los niveles del componente C3, y con un aumento de los inmunocomplejos circulantes. Nuestros resultados sugieren la posible utilidad de estos mecanismos para evaluar otras funciones del complemento, no detectadas mediante una determinación de la actividad hemolítica, como medida de la función de las vías clásica y alternativa.

Hipocomplementemia en pacientes con enfermedad de Hodgkin / Hypocomplementaemia in patients with Hodgkin disease

Se determinó la actividad hemolítica de las vías clásica, alternativa, del factor B, del factor D, así como los niveles de C1q, C3 y C4, en el suero de 24 pacientes adultos con enfermedad de Hodgkin en diferentes estadios clínicos. Se detectó una disminución significativa (p < 0,001) de las vías clásica, alternativa, factor B y la concentración de C3 y C4 en los estadios más avanzados de la enfermedad, IIIB y IVB. Los datos obtenidos en nuestro trabajo sugieren una posible asociación entre las alteraciones del sistema complemento con la extensión de la enfermedad.

A Case of Membranoproliferative Glomerulonephritis Type II (Dense-Deposit Disease)

Membranoproliferative glomerulonephritis type II(MPGN II), also called dense deposit disease, was first described by Berger and Galle in 1963. The diagnosis of MPGN II is based on electron-microscopic finding of an intensely electron-dense substance which replaces the lamina densa of the glomerular basement membrane. Although the etiology and pathogenesis of MPGN II are unknown, it frequently progresses to end-stage renal failure. Typically in MPGN II, hypocomplementemia due to activation of the alternative complement pathway is present. In addition, the association of MPGN II with partial lipodystrophy and complement abnormalities is well documented. The relationship between these associated features and the patient's renal functional outcome is not clear. With respect to the therapy for MPGN II, an alternate-day prednisolone regimen was shown to be effective. Various treatment modalities, including immunosuppression with corticosteroids, cytotoxic drugs and cyclosporin A, anticoagulants and antiplatelet therapies are used, either alone or in combination, with varying degrees of success. The purpose of this paper is to present a case of MPGN II from a 7 years old girl with paroxysmal supraventricular tachycardia(PSVT).

A Case of Membranoproliferative Glomerulonephritis Type II (Dense-Deposit Disease)

Membranoproliferative glomerulonephritis type II(MPGN II), also called dense deposit disease, was first described by Berger and Galle in 1963. The diagnosis of MPGN II is based on electron-microscopic finding of an intensely electron-dense substance which replaces the lamina densa of the glomerular basement membrane. Although the etiology and pathogenesis of MPGN II are unknown, it frequently progresses to end-stage renal failure. Typically in MPGN II, hypocomplementemia due to activation of the alternative complement pathway is present. In addition, the association of MPGN II with partial lipodystrophy and complement abnormalities is well documented. The relationship between these associated features and the patient's renal functional outcome is not clear. With respect to the therapy for MPGN II, an alternate-day prednisolone regimen was shown to be effective. Various treatment modalities, including immunosuppression with corticosteroids, cytotoxic drugs and cyclosporin A, anticoagulants and antiplatelet therapies are used, either alone or in combination, with varying degrees of success. The purpose of this paper is to present a case of MPGN II from a 7 years old girl with paroxysmal supraventricular tachycardia(PSVT).

Viscosuplementación como alternativa de tratamiento en osteoartritis de rodilla: experiencia clínica / Viscosupplementation as treatment alternative of the knee osteoarthritis: clinical experience

La orteoartritis es la más común de las afecciones articulares, siendo más frecuente en la rodilla. La vicosuplementación es una nueva alternativa en el tratamiento de esta entidad. Presentamos los resultados de una serie de treinta rodillas (veintitrés pacientes) tratatadas con inyección intra - articular de Hylan G-F 20 (Synviscs) a razón de una aplicación semanal por tres dosis, con un seguimiento promedio de 44,6 semanas postratamiento. Se utilizó la escala análoga visual (EAV) x 100 para valorar el dolor, el nivel de actividad para valorar la función y la gradación de Kellegren Lawrence para el estadio radiológico de la osteoartrosis. Veinticinco rodillas (83,33 por ciento) presentaron evolución satisfactoria, dada por mejoría del dolor y de la función articular, en cinco rodillas (16,77 por ciento) los resultados fueron pobres. Recomendamos la viscosuplementación como alternativa valiosa para el tratamiento de pacientes con osteoartrosis de rodillas en los estadios iniciales, cualquiera sea la edad del paciente

Sistema del complemento e inmunocomplejo en el mieloma múltiple / Complement system and circulating immune complexes in multiple myeloma

Se determinó la frecuencia de 29 antígenos HLA de los loci A y B en 20 pacientes con glaucoma primario de ángulo abierto diagnósticados en el Servicio de Oftalmología del Hospital General Docente ®Enrique Cabrera¼. Se utilizaron como controles 276 personas sanas. El antígeno HLA B35 mostró asociación positiva con un riesgo relativo (RR) de 5,3. Se obtuvo una frecuencia estadísticamente significativa con una p corregida (pc) <0,002 para el HLA B35 al compararla con controles normales no relacionados. El resto de los antígenos HLA estudiados no mostraron asociación

Effects of Sodium Alginate on the Non-Specfic Defense System of the Common Carp ( Cyprinus carpio L. ) / 대한면역학회지

Carp which receive intraperitoneal injections of sodium alginate show a high survival rate after being challenged with Edwardsiella tarda. To elucidate the immunoenhancement by sodium alginate, its effects on the non-specific defense system of carp were investigated. Sodium alginate had little influence either on the activity of the alternative complement pathway or on the phagocytic and respiratory burst activities of head kidney phagocytes (HKP), yet it greatly enhanced the migration of HKP to the peritoneal cavity (the site of injection) and concurrently elevated their phagocytic activity. The number of phagocytes mobilized by sodium alginate was 2 to 50 times greater than that by the well-known peritoneal exudate cell-eliciting agents when injected at the same dose. Accordingly, it is highly probable that the early elimination of challenge bacteria by such mobilized and activated phagocytes was responsible for the high survival rate of the alginateinjected fish. In chemotaxis assays, it was revealed that sodium alginate stimulated sorne leukocyte subpopulation (s) within the peritoneal cavity to produce and/or secrete chemotactic factor (s), while concurrently enhancing the sensitivity of HKP to the factor (s).