A Leishmaniose Visceral Humana (LVH) é uma protozoonose sistêmica grave que tem apresentado mudança no comportamento epidemiológico, com uma tendência crescente no Brasil. Na Região Norte, com a criação do Estado do Tocantins em 1989, houve aumento da incidência de LV em decorrência das modificações ecoepidemiológicas. Foi realizado um estudo descritivo de corte transversal para avaliar o quadro da LVH no município de Araguaína (TO) no período de janeiro de 2007 a agosto de 2010. Adicionalmente, foram realizados ensaios para comparar as abordagens diagnósticas sorológicas para o diagnóstico da doença. Na distribuição dos casos de LVH nos municípios do norte do estado do Tocantins, Araguaína representa 79,8% no total dos casos no período de 2.007 a agosto de 2.010. Os resultados deste estudo revelaram que, nesse período, 769 casos foram confirmados, sendo que 98,7% foram de casos novos. Houve um predomínio do sexo masculino de 57,8% e a faixa etária mais acometida foi a de 0 a 14 anos, com 71,3% dos casos notificados. Na distribuição por zona de residência, foram notificados 98,5% dos casos na zona urbana, mostrando a urbanização da doença. Nos ensaios, foram utilizadas uma abordagem usual da rede do SUS: um ensaio de imunofluorescência indireta (IFI), um ELISA convencional, somados a um ELISA dissociativo. Os ensaios de ELISA apresentaram alta reprodutibilidade. Os pacientes positivos à IFI apresentaram uma frequência de 4% de falso-positivos quando testados em ambos os ELISA. Entre os pacientes suspeitos, houve uma alta frequência de positivos ao ELISA, maior no ELISA dissociativo do que no ELISA convencional. Na população assintomática, houve um achado de amostras positivas ao ELISA dissociativo. A presença de imunocomplexos em pacientes assintomáticos no início da doença ou sua presença em pacientes com resposta humoral menos intensa, como crianças, pode explicar estes achados de maior positividade no ELISA dissociativo. A confirmação destes resultados depende da pesquisa parasitológica em pacientes positivos ao ELISA dissociativo. Estes resultados mostram a importância de novas abordagens sorológicas no diagnóstico da LVH que viabilizariam uma triagem de paciente para diagnóstico parasitológico invasivo. / Human visceral leishmaniasis (HVL) is a severe systemic protozoonosis that has presented changes at the epidemiological behavior, with a growing trend in Brazil. It has been conducted a cross sectional study to assess the context of HVL in the city of Araguaina (TO) from January 2007 to August 2010. Additionally, tests were conducted to compare the diagnostic approaches for the serological diagnosis. In the distribution of cases of HVL in the districts of northern state of Tocantins, Araguaina represents 79.8% of the total cases in the period from 2007 to August 2010. The results of this study revealed that in this period, 769 cases were confirmed, while 98.7% are new cases. There was a male predominance of 57.8% and the most affected age group was 0-14 years, with 71.3% of reported cases. In the distribution by area of residence were reported 98.5% of cases in the urban area, showing the urbanization of the disease. In tests, we used the usual approaches network: an indirect immunofluorescence assay (IFA) and a conventional ELISA, plus a dissociative ELISA. ELISA assays showed high reproducibility. Positive patients with IFAT showed a frequency of 4% false-positive when tested in both ELISA. Among patients suspected there was a high frequency of positive to ELISA, the ELISA dissociative higher than in the conventional ELISA. In the asymptomatic population, there was a finding of positive samples by ELISA dissociative. The presence of immune complexes in asymptomatic patients early in the disease or its presence in patients with less intense humoral response, as children, these findings may explain the higher dissociative ELISA positive. Confirmation of these results depends on parasitologic research on dissociative ELISA-positive patients. These results show the importance of new approaches in the serological diagnosis LVH that would make a screening of patients for invasive diagnostic parasitology.

Activation of the cysteine protease caspase-1 and the subsequent processing and secretion of the pro-inflammatory cytokines IL-1Β and IL-18 is central to the inflammatory response as well as the induction of adaptive immune responses. Caspase-1 is activated as a part of a high-molecular weight multi-protein complex termed the inflammasome. The NLRP3 inflammasome is by far the best studied of these complexes, and it is the most promiscuous in terms of activating signals. The diversity of NLRP3 activating signals makes it likely that NLRP3 does not recognize each agonist directly, rather it detects a molecule that is generated, revealed, or altered by cellular stress. Recent studies have indicated that mitochondrial dysfunction is crucial for NLRP3 inflammasome activation, yet the activating ligand has not yet been identified. Appropriate and timely activation of this inflammatory pathway is required for host immunity to a variety of pathogens, however dysregulated activation leads to autoinflammation and potentially autoimmunity. Hence it is important to identify mechanisms for inflammasome activation and regulation. Therefore, this dissertation has focused on investigating the mechanisms for activation and regulation of the NLRP3 inflammasome, and the biological consequences of these changes. We show that the mitochondrial lipid cardiolipin is required for NLRP3 inflammasome activation. We have also identifying a novel mechanism by which inflammasome activation is regulated. Data presented in this dissertation shows that IgG immune complexes effectively suppress inflammasome activation and the subsequent processing and secretion of IL-1Α and IL-1Β. Furthermore we show that immunization with IgG immune complexes suppresses both Th2 and Th17 immune responses. Together these data provide novel insights into the activating and regulatory pathways of both the innate and adaptive immune systems.

Se estudió la incidencia de déficits del sistema complemento en pacientes con enfermedad meningocócica, detectándose 4 pacientes con déficit completo en la actividad hemolítica mediada por el complemento (ensayo de CH50). Tres de ellos tenían un déficit completo del factor C8, dos de los cuales pertenecían a la misma familia, y el cuarto paciente presentaba un déficit parcial de C3, secundario a la presencia de un factor activador de la vía alterna del complemento, conocido con factor nefrítico, o C3-nef. En los casos con déficit de C8 se llevó a cabo un estudio familiar, detectándose otro individuo más con déficit de C( y nueve sujetos con déficit parcial (inviduos heterocigotos). Así mismo se analizaron los niveles de complejos inmunes circulantes, mediante dos tecnicas diferentes: la fijación a C1q y la unión a células Raji. Los resultados no muestran asociación entre los niveles de CIC y la severidad del cuadro clínico. / We analyzed the incidence of complement deficiencies in patients with acute meningocococcal disease. We detected four patients with recurrent meningococcal infections having a complete lack of serum haemolitical activity (CH50 assay). Three of then had a complete absence of CD8 in serum and the four patient had an aberrant activation of the alternative complement pathway due to the presence of C3-nef. Familial studies were done in the cases of C8 deficiencies, in which a fourth member was identified, together with nine individuals with a partial (heterocygotic) C8 deficiency. Finally we evaluated the levels of circulating immune complexes (CIC) by binding to C1q or to Raji cells. Our results showed a lack of association between the severity of the disease and the levels of CIC.

A produção de espécies reativas de oxigênio (ERO) pelos neutrófilos, que representa um mecanismo essencial da imunidade inata contra agentes infecciosos, pode ser desencadeada por imunocomplexos (IC) associados ou não com componentes do sistema complemento. Os IC são normalmente eliminados da circulação pela ligação aos receptores de complemento do tipo 1 em eritrócitos, que os transportam até o baço e o fígado, onde são fagocitados por macrófagos residentes. Porém, defeitos neste mecanismo de eliminação podem levar à deposição de IC nos vasos e tecidos. Em algumas doenças inflamatórias, onde ocorre uma intensa deposição de IC, pode acontecer o recrutamento e a ativação maciça de neutrófilos pelos IC. Nessa situação, os mecanismos endógenos de defesa tecidual não conseguem controlar as alterações desencadeadas pelos fatores oxidantes e líticos liberados pelos neutrófilos, levando à possível lesão tecidual e consequências funcionais e estruturais para o organismo. Nessa perspectiva, tem-se intensificado, nos últimos anos, a procura por novos compostos terapêuticos com capacidade de reduzir os danos aos tecidos adjacentes ao acúmulo de IC, neutrófilos, ERO e enzimas líticas, expostos a níveis deletérios desses componentes. Assim, neste trabalho foi avaliado o potencial antioxidante de um conjunto de dez derivados 3-fenilcumarínicos no metabolismo oxidativo de neutrófilos humanos estimulados por ICs, empregando-se o ensaio de quimioluminescência dependente de luminol e de lucigenina (QLlum e QLluc, respectivamente). Posteriormente, foi avaliada a citoxicidade das amostras, através do ensaio de exclusão do azul de tripan e medida da atividade da lactato desidrogenase liberada, bem como sua capacidade de sequestrar HOCl e inibir a atividade das enzimas NADPH oxidase e mieloperoxidase (MPO). Observou-se que todas as amostras avaliadas inibiram a QLlum e a QLluc, sendo que cinco delas tiveram efeito inibitório maior que ou igual a 50% (C6, C13, C13a, C24 e C24a)*. Este efeito biológico não foi mediado pela citotoxicidade das 3-fenilcumarinas, nas condições avaliadas. Dentre essas amostras, o derivado 3-fenilcumarínico C13, que foi o mais efetivo em inibir a QLluc, possui duas características que parecem estar relacionadas com tal efeito: um grupo substituinte orto-diidroxi no esqueleto cumarínico e um grupo metilenodioxila no anel fenílico. Além do mais, todas as substâncias que possuem o grupo metilenodioxila no anel fenílico (C1, C6, C6a, C13, C13a) apresentaram efeito inibitório da QLluc maior que as respectivas análogas sem este substituinte (C15, C18, C18a, C24, C24a). A inibição da QLluc parece ser independente da inibição da atividade da NADPH oxidase, visto que as substâncias apresentaram efeito inibitório discreto no consumo de O2 pelos neutrófilos estimulados por IC. Por outro lado, as amostras C13 e C24, que têm em comum a presença do grupo substituinte 6,7-diidroxi, apresentaram os maiores efeitos inibitórios sobre a QLlum, apresentando IC50 semelhante. Essas duas substâncias também foram as mais ativas em inibir a atividade da enzima MPO e em sequestrar o HOCl. Para esses dois ensaios, a atividade biológica observada foi dependente do número de hidroxilas na estrutura do derivado 3-fenilcumarínico. Os resultados deste trabalho mostram que a atividade antioxidante dos derivados 3-fenilcumarínicos sobre o metabolismo oxidativo de neutrófilos humanos está relacionada às características estruturais dessas moléculas. Dentre a série de substâncias avaliadas, C13 e C24 são as amostras mais promissoras para uso como protótipos de moléculas com aplicação terapêutica na modulação desta função neutrofílica. / Production of reactive oxygen species (ROS) by neutrophils, which is an essential mechanism of innate immunity against infectious agents, can be triggered by immune complexes (IC) associated or not with components of the complement system. IC are normally cleared from the circulation by binding to complement receptor type 1 on erythrocytes and transport to spleen and liver, where they are phagocytized by resident macrophages. However, defects in this clearance mechanism can lead to deposition of IC in vessels and tissues, favoring neutrophil chemotaxis. In some inflammatory diseases there is intense deposition of IC, which triggers massive recruitment and activation of neutrophils. In these situations, the endogenous tissue defense mechanisms are not able to regulate the local disorders provoked by the oxidant and lytic compounds released by neutrophils, and tissue damage as well as structural and functional consequences to the organism might occur. In this perspective, the last years have been marked by an intense search for new therapeutic compounds able to reduce the damage to tissues surrounding the site of accumulation of IC, neutrophils, ROS and lytic enzymes, exposed to deleterious levels of these components. So, the present work reports the evaluation of the antioxidant potential of ten 3-phenylcoumarin derivatives in the neutrophil oxidative metabolism stimulated with IC, through the luminol- and lucigenin-dependent chemiluminescence assay (QLlum and QLluc, respectively). Further, cytotoxicity of the samples was evaluated by the trypan blue exclusion assay and measurement of lactate dehydrogenase activity, as well as their ability to scavenge HOCl and inhibit NADPH-oxidase and myeloperoxidase (MPO) activity. We found that all the samples inhibited QL-lum and QLluc, being the inhibitory effect of five of them higher than or equal to 50% (C6, C13, C13a, C24 e C24a)*. This biological effect was not mediated by cytotoxicity of the 3-phenylcoumarins, under the conditions assessed. Compound C13, which was the most effective inhibitor of QLluc among the set of phenylcoumarins tested, has two structural features that seem to be related to this effect: an orto-dihydroxyl group in the coumarin moiety and a methylenedioxyl group attached to the phenyl ring. Moreover, the inhibitory effect of all 3-phenylcoumarins bearing the methylenedioxyl group (C1, C6, C6a, C13, C13a) was higher than that found to their analogues without this group (C15, C18, C18a, C24, C24a). The CLluc inhibition by phenylcoumarins seems to be independent of inhibition of NADPH-oxidase activity, since these compounds had a slight inhibitory effect in the O2 consumption by IC-stimulated neutrophils. On the other hand, compounds C13 and C24, which shares the 6,7-dihydroxyl group, had the highest inhibitory effects on CLlum with similar IC50 values among the samples tested. These compounds were also the most active ones to inhibit MPO activity and scavenge HOCl. Such biological effects were dependent on the number of hydroxyl groups in the 3-phenylcoumarin moiety. The results of this work show that the antioxidant activity of 3-phenylcoumarin derivatives in the oxidative metabolism of human neutrophils is related to the structural characteristics of these molecules. Among the set of compounds evaluated, C13 and C24 are the most promising samples to be used as prototypes of moleculse with therapeutic application in the modulation of neutrophil function.

A formação de complexos antígeno-anticorpo ou imunocomplexos (ICs) na circulação e sua eliminação faz parte dos mecanismos de defesa imune humoral do ser humano. Em algumas patologias, como lupus eritematoso sistêmico, artrite reumatóide e vasculite auto-imune, ocorre um desequilíbrio nesse processo, que leva à deposição dos ICs nos tecidos e ao desencadeamento de uma reação inflamatória. Esta, por sua vez, envolve o recrutamento e ativação de neutrófilos, que têm importante participação na patogênese dessas doenças. A ativação dos neutrófilos pelos ICs, via receptores para a porção Fc de IgG (FcR) e receptores de complemento (CR), desencadeia diversas funções efetoras, tais como fagocitose, desgranulação e o metabolismo oxidativo, com a produção de espécies reativas de oxigênio (EROs). Estas funções estão envolvidas na digestão dos ICs, na morte de microorganismos, e na regulação do processo inflamatório. Entretanto, nas doenças mediadas por ICs, os neutrófilos ativados liberam grandes quantidades de enzimas e EROs para o meio extracelular, contribuindo para a lesão dos tecidos do hospedeiro e a amplificação do processo inflamatório. Neste trabalho foi avaliado o efeito modulatório de vinte derivados de 3-fenilcumarina nas funções de neutrófilos estimulados por ICs de ovalbumina (OVA) e IgG anti-OVA. Além disso, foi feita a investigação mecanismos de ação dessas substâncias e a análise da relação estrutura-atividade. O metabolismo oxidativo dos neutrófilos ativados por ICs foi medido por ensaio de quimioluminescência dependente de lucigenina ou de luminol (QLlucPMN e QLlumPMN, respectivamente). Observou-se que as 3-fenilcumarinas contendo o grupo substituinte 3,4-metilenodioxi e o grupo substituinte 6,7-orto-diidroxi (C13) ou 6,7-orto-diacetoxi (C13a), bem como a 3-fenilcumarina 6,7,3,4-tetraacetoxilada (C24a), apresentaram atividade inibitória maior que a quercetina (QUER) sobre a QLlucPMN e a QLlumPMN. Para as demais substâncias avaliadas, que foram tão ou menos ativas que a QUER, as características estruturais relacionadas à inibição da QLlucPMN foram um pouco diferentes daquelas relacionadas à inibição da QLlumPMN. Além disso, as 3-fenilcumarinas estudadas e a QUER não apresentaram efeito tóxico sobre os neutrófilos, avaliado pela liberação de lactato desidrogenase e pelo ensaio de exclusão ao corante Azul de Tripan, nas condições empregadas. Para as três 3-fenilcumarinas que apresentaram maior efeito inibitório sobre o metabolismo oxidativo dos neutrófilos (C13, C13a e C24a), o aumento do tempo de pré-tratamento levou a uma tendência de redução do efeito inibitório da substância C24a, mas não influenciou na atividade biológica das substâncias C13 e C13a. Essas três substâncias não interferiram na capacidade fagocítica das células, avaliada por microscopia eletrônica de transmissão. Para todas as 3-fenilcumarinas foi avaliada também a capacidade antioxidante frente ao radical livre 2,2-difenil-1-picril-hidrazil e o efeito inibitório dessas substâncias sobre a quimioluminescência produzida pela reação horseradish peroxidase-H2O2-luminol (QLHRP). Foi observado que a QUER e as 3-fenilcumarinas contendo o grupo substituinte orto-diidroxi (C13, C23, C24) tiveram atividade antioxidante e inibiram a QLHRP, mas suas análogas acetoxiladas (C13a, C23a, C24a), bem como as demais substâncias avaliadas, foram significativamente menos ativas nesses modelos experimentais não celulares. O conjunto de resultados deste trabalho sugere que as atividades biológicas das 3-fenilcumarinas estudadas foram dependentes de suas estruturas químicas, e pequenas modificações nestas podem levar a alterações significativas na magnitude de seus efeitos biológicos. Além disso, tanto a lipofilicidade das substâncias quanto a sua capacidade antioxidante parecem ser relevantes para a modulação eficiente do metabolismo oxidativo dos neutrófilos e da conseqüente lesão tecidual. / Formation and clearance of circulating antigen-antibody complexes or immune complexes (ICs) take part in the humoral immune defense mechanisms. In some diseases, as systemic lupus erythematosus, rheumatoid arthritis and auto-immune vasculitis, an imbalance of this process occurs, leading to the ICs deposition within tissues and triggering an inflammatory reaction. The last one involves the recruitment and activation of neutrophils, which have an important role in the pathogenesis of such diseases. Neutrophil activation by ICs, via receptors for the Fc portion of IgG (FcgR) and complement receptors (CR), triggers a sort of effector functions, such phagocytosis, degranulation and the oxidative metabolism, which produces reactive oxygen species (ROS). These functions are involved in the ICs digestion, microbial killing and the inflammatory process regulation. However, the activated neutrophils release large amounts of enzymes and ROS to the extracellular milieu, contributing to the tissue damage and amplification of the inflammatory process in the IC-mediated diseases. In this work, we evaluated the modulatory effect of twenty 3-phenylcoumarin derivatives in the neutrophil functions stimulated by ICs of ovalbumin (OVA) and IgG anti-OVA. In addition, the mechanisms of action of these compounds were investigated, and the structure-activity relationship was analyzed. The IC-activated neutrophil oxidative metabolism was measured by lucigeninor luminol-dependent chemiluminescence assay (CLlucPMN and CLlumPMN, respectively).It was observed that the 3-phenylcoumarins bearing a 3,4-methylenodioxy and the 6,7-orto-dihydroxy (C13) or the 6,7-orto-diacetoxy (C13a) group, as well as the 6,7,3,4-tetraacetoxylated 3-phenylcoumarin (C24a), inhibited CLlucPMN and CLlumPMN more than quercetin (QUER). Regarding the other evaluated compounds, whose inhibitory effects were similar to or lower than QUER, the structural features related to the CLlucPMN inhibition were different from those related to the CLlumPMN inhibition. Moreover, the studied 3-phenylcoumarins and QUER had no toxic effects on neutrophils, as evaluated by lactate dehydrogenase release and Trypan Blue exclusion, under the assessed conditions. With respect to the three 3-phenylcoumarins that had the highest inhibitory effects on the neutrophil oxidative metabolism (C13, C13a and C24a), the increase of the cell pre-treatment period showed a tendency to decrease the inhibitory ability of compound C24a, but did not influence the biological activity of compounds C13 and C13a. These three compounds did not interfere in the neutrophil phagocytic ability, as evaluated by transmission electron microscopy. The antioxidant activity against the 2,2-diphenyl-1-picrylhydrazyl free radical and the inhibitory effect in the chemiluminescence generated by the horseradish peroxidase-H2O2-luminol reaction (CLHRP) were evaluated for all 3-phenylcoumarins. It was found that QUER and those 3-phenylcoumarins bearing the orto-dihydroxy group (C13, C23, C24) had antioxidant activity and inhibited the CLHRP. However, their acetoxylated analogues (C13a, C23a, C24a) and the other evaluated compounds were significantly less active on these cell-free experimental models. Taken together, the results of the present work suggest that the biological activities of the 3-phenylcounarins here investigated were dependent on their chemical structures, and small changes on the molecule can lead to significant changes on the magnitude of their biological effects. Moreover, both lipophilicity and antioxidant capacity of these compounds seem to be relevant to an efficient modulation of the neutrophil functions and the consequent tissue damage.

Made available in DSpace on 2016-08-10T10:29:27Z (GMT). No. of bitstreams: 1 VERISSA MARTINS TEIXEIRA.pdf: 734398 bytes, checksum: ba115878ec5516b813d6bc6eedc4c03d (MD5) Previous issue date: 2010-10-01 / Visceral Leishmaniasis (VL), a widespread disease, becomes relevant for its high incidence and lethality in different countries around the world. Brazil follows the global trend, reaching 21 federate units. In the state of the Tocantins the illness indices are high, especially in the city of Araguaína, among the most prevalent of the country. The VL behaves as typical zoonose, the sandflies as vector and the dog as the main reservoir. In the urban area these canids are considered the main infection source due to the high skin parasitism and the man proximity. The canine epidemic is still important for it generally comes from the human epidemic. The diagnosis of the human and canine infection is mainly based on serological methods, in which the Enzyme Linked Immunosorbent Assay (ELISA) stands out. Due to the illness endemic character, the more effective diagnostic methods became primordially available. Aiming to provide safer results free of interferences, as unspecified and immune complex reactions, frequently observed in the immune diagnostic of the human and canine VL, accomplished in this research, variations of the ELISA in serum samples from 140 dogs from the Tocantins endemic region. Verifying if there are unspecified reactions in the ELISA tests urea was added to the samples as diluents. The reduction of the optic densities was observed in the tested samples, presuming that it was break in the weak links or of low antibodies. Glicine and Tris were added to evaluate the interference of the immune complexes in the ELISA test to evaluate the interference with the pH shock, proving that there was an increase of the absorbing rate. These results suggest that method is effective to eliminate the complex antibodies, which had been blocked by circulating antigens. It is believed that the results acquired in this work are relevant in the perspective of the constant search for the diagnostic improvement of infectious and parasitic illnesses. / A leishmaniose visceral (LV), enfermidade de ampla distribuição, torna-se relevante pela alta incidência e letalidade relatadas em diferentes países do mundo. O Brasil acompanha a tendência global, com 21 unidades federadas atingidas. No estado do Tocantins são altos os índices da doença, especialmente na cidade de Araguaína, encontrada entre as mais prevalentes do país. A LV comporta-se como uma típica zoonose, tendo um flebótomo como vetor e o cão como o principal reservatório. Na área urbana esses canídeos são considerados a principal fonte de infecção devido ao alto parasitismo cutâneo e à proximidade ao homem. A epidemia canina é ainda importante por geralmente preceder a epidemia humana. O diagnóstico da infecção humana e canina baseia-se principalmente em métodos sorológicos, entre eles se destaca o Ensaio Imunoenzimático (ELISA). Devido ao caráter endêmico da doença, torna-se primordial que métodos diagnósticos mais efetivos sejam disponibilizados. Com o objetivo de fornecer resultados mais seguros e livres de interferentes, como reações inespecíficas e imunocomplexos, frequentemente observados no imunodiagnóstico da LV humana e canina, realizou-se através deste trabalho, variações de Ensaio Imunoenzimático em amostras de soro de 140 cães procedentes de região endêmica do estado do Tocantins. Para verificar se havia reações inespecíficas em testes ELISA adicionou-se ureia como diluente das amostras. Observou-se a diminuição das densidades ópticas das amostras testadas, presumindo que houve a quebra de ligações fracas ou de anticorpos de baixa avidez. Para avaliar a interferência de imunocomplexos no ensaio ELISA foram adicionados Glicina e Tris, com choque de pH, constatando-se que houve aumento do título das absorbâncias. Estes resultados sugerem que o método é efetivo para eliminar os anticorpos complexados, antes bloqueados por antígenos circulantes. Acredita-se que os resultados obtidos através deste trabalho sejam relevantes na perspectiva da busca constante pelo aprimoramento diagnóstico de doenças infecciosas e parasitárias.

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease. HTLV-1 Related Endogenous Sequence (HRES-1), a human endogenous retrovirus, produces 2 retroviral-like Gag capsid proteins (p8 and p15) that share significant sequence homology to the U1-subunit of the small ribonucleoprotein complex (U1sn-RNP), an autoantigen of lupus. The central hypothesis is that molecular mimicry between HRES-1 and U1sn-RNP serves as a priming event in SLE via the production of cross-reactive autoantibodies. Anti-HRES-1/U1sn-RNP serological responses in subjects with SLE and comparison populations were characterized. An overlapping peptide set mapping the HRES-1 p8 and p15 proteins was used. SLE subjects produce IgG to several regions of HRES-1. Healthy subjects or those with RA, HIV-1 infection, or HTLV-1-infection produced no significant anti-HRES-1 IgG. Anti-HRES-1 antibodies deposited in the kidneys of patients with SLE glomerulonephritis were identified. Our data suggests that HRES-1 plays a role in SLE by means of a molecular mimicry mechanism with U1sn-RNP.

Abstract The purpose of this study was to develop sensitive and specific laboratory diagnostic methods for the demonstration of pneumococcal surface antigens or pneumococcus-specific antibodies in clinical samples. The work took account of epidemiological aspects of both pneumococcal disease and nasopharyngeal carriage of pneumococcus. We first compared the sensitivity of pneumococcal culture and antigen detection methods in nasopharyngeal samples in a developing country setting and then investigated the possibility of improving the sensitivity of the antigen detection by introducing an enrichment step in the procedure. — Further investigations were designed to determine the validity of pneumolysin-specific immune complex bound antibody assay as a tool for diagnosing pneumococcal ALRI in a developing country setting. Finally, we developed an enzyme immunoassay for the detection of pneumococcal capsular polysaccharide antigens, using type-specific antibodies produced in-house in rabbits through immunisation with an in-house-produced pneumococcal whole cell vaccine. The method was tested in nasopharyngeal and middle ear fluid samples. The first results indicated that antigen detection might be more sensitive than culture in demonstrating pneumococci in URT, particularly in children with prior antimicrobial therapy. Antigen detection is a feasible method for studies on pneumococci in developing countries. For type-specific demonstration of S. pneumoniae, detection of pneumococcal antigen after an enrichment step proved a sensitive method that can be applied for epidemiologic study purposes, e.g., in vaccine trials, in areas without ready access to a good microbiology laboratory. Determination of IC-bound pneumolysin IgG antibodies appears to be a useful method for species-specific diagnosis of pneumococcal infections. The results indicating pneumococcal aetiology in ALRI patients in this study compare well with the best results obtained by the use of lung aspirates. Increasing the number of serial samples improves the sensitivity of the assay, but even two samples provide more positive findings than other methods currently in routine use. Criteria of positivity need to be confirmed in subsequent larger studies with both healthy controls and patients with confirmed pneumococcal disease. It is also important to control the findings in patients with pneumonia of non-pneumococcal origin. The novel enzyme immunoassay was shown to work well with enrichment culture samples, with an almost 100% sensitivity compared with the culture. Middle ear fluid samples were too diluted for the enzyme immunoassay method used, and only 74% sensitivity compared with culture was achieved. Provided that adequate samples can be obtained, the method will be a useful complement to the current laboratory methods used to diagnose pneumococcal disease. With the existence of a broad spectrum of microbiological and immunological methods, it is imperative to seek international consensus for standard methods to demonstrate pneumococcus. Otherwise it is very difficult to compare results from different clinical studies. A WHO Working Group recently proposed a standard method for detecting upper respiratory carriage of pneumococcus, but a lot of work remains to be done in other areas of research on pneumococcal infections.

La nétose du polynucléaire neutrophile (PN) correspond à la libération de filaments d’ADN recouverts de protéines appelés Neutrophil Extracellular Trap (NETs). Outre leur rôle anti-infectieux, les NETs représentent des acteurs émergents de nombreuses pathologies inflammatoires et nous avons souhaité évaluer leur implication au cours de réactions allergiques.Au cours d’une étude clinique multicentrique notre équipe a mis en évidence un mécanisme alternatif de l’anaphylaxie aux curares, impliquant les PN. La phase aiguë de ces réactions s’accompagne d’une libération de NETs dont la concentration est corrélée avec la sévérité et avec une diminution de l’expression des récepteurs activateurs des IgG à la surface des PN (FcγRs) ; ceci suggère un rôle des complexes immuns (CI) IgG/curares dans la formation des NETs au cours de ces réactions anaphylactiques.Pour confirmer cette hypothèse, la capacité d’activation de la nétose par les CI IgG a été étudiée, via la mise au point d’un modèle de stimulation in vitro des PN humains purifiés.Ce travail montre que 2 récepteurs aux IgG du PN (FcγRIIa et FcγRIIIB) contribuent à la libération de NETs en réponse à différents types de CI.En parallèle, la formation des NETs a été explorée dans un modèle de réaction allergique chronique, l’asthme. Au niveau systémique, la concentration de NETs est associée à la présence d’un asthme sévère mal contrôlé et d’une obstruction bronchique peu réversible. Inversement, la concentration de NETs dans le lavage broncho-alvéolaire est plus élevée au cours de l’asthme modéré et semble traduire un recrutement pulmonaire et une activation des PN en réponse à une colonisation microbienne.Au total nous montrons que les NETs sont libérés au cours des deux modèles de réactions allergiques choisis, aiguë (anaphylaxie aux curares) et chronique (asthme) et qu’ils pourraient représenter des biomarqueurs de sévérité. Des travaux complémentaires sont nécessaires pour déterminer dans quelle mesure les NETs contribuent à la physiopathologie des allergies. / Neutrophil netosis consists in the release of extracellular DNA filaments bound to granular proteins, called Neutrophil extracellular traps (NETs). In addition to their anti-infectious role, NETs are emerging actors of many inflammatory diseases and we decided to investigate their involvement during allergy.In a multicenter clinical study, our team highlighted an alternative mechanism of anaphylaxis to neuromuscular blocking agents (NMBA) involving neutrophils (PN). The acute phase of these reactions is characterized by NETs release which level is correlated with severity and with a decrease in IgG activating receptors (FcγRs) expression on PN; this suggests a role of immune complexes (IC) IgG / NMBA in NETs formation during these anaphylactic reactionsTo confirm this hypothesis, the ability of IgG ICs to activate netosis was studied through the development of an in vitro stimulation model of purified human PNs.This work shows that two PN IgG receptors (FcγRIIa and FcγRIIIB) contribute to NET release upon cellular activation by different ICsIn parallel, NETs formation has been explored in a model of chronic allergic reactions, asthma. At systemic level, NETs levels are associated with severe and poorly controlled asthma as well with the presence of low reversible bronchial obstruction. Conversely, NETs levels in bronchoalveolar lavage are higher in moderate asthma and appear to reflect pulmonary recruitment and activation of PN in response to microbial colonization.Taking together these results show that NETs are released during the two selected models of allergic reactions : acute (NMBA anaphylaxis) and chronic (asthma) and could be used as biomarkers of severity. Furthers works are needed to determine to what extent NETs contribute to the pathophysiology of allergy.

A Aspergilose Broncopulmonar alérgica (ABPA) é uma doença complexa,desencadeada por uma reação de hipersensibilidade ao Aspergillus fumigatus, que apresenta vários estágios, sendo que no estágio mais grave, os pacientes apresentam bronquiectasias. O diagnóstico da doença é difícil e o maior problema é a falta de antígenos padronizados necessários para a determinação de anticorpos específicos. O objetivo do presente estudo é avaliar se os testes cutâneos com os análogos de Asp f 1 podem auxiliar no diagnóstico e no estadiamento da ABPA. Três grupos de pacientes classificados por testes sorológicos foram obtidos a saber 20 ABPA (16BQ+; 4BQ-), 25 possíveis -ABPA (14BQ+;11BQ-) e 24 asmáticos sem ABPA (11BQ+;13BQ-). Fizeram parte do estudo 10 pessoas sem asma . Todos foram submetidos a testes intradérmicos com três antígenos a-sarcina, mitogilina e estrictocina.Houve uma intensa reação a todos os antígenos e as reações produzidas foram semelhantes para os três antígenos. As reações de leitura tardia positivas à mitogilina foram biopsiadas. As biopsias de 2 (12,5%) dos pacientes BQ+ do grupo ABPA e 5 do grupo ABPA possível com BQ+ (35,6%) mostraram vasculite por depósito de imunocomplexos. 11 pacientes do terceiro grupo não apresentaram vasculite. O quarto grupo não apresentou reação tardia. Todos os pacientes com reação positiva apresentaram BQ+. alfa-sarcina, a mitogilina e a restrictocina diferenciaram pacientes com ABPA por testes intradérmicos e podem ser aplicados no diagnóstico da doença. A maior incidência de bronquiectasias foi encontrada no primeiro grupo (80%) e no segundo (56%). No terceiro grupo nenhum caso foi encontrado em 23 pacientes com asma e teste ID positivo ao aspergillus fumigatus todos os pacientes com vasculite tinham bronquiectasia. Há possibilidade de que as lesões produzidas nos pulmões sejam produzidas por vasculite. / Allergic Bronchopulmonary Aspergillosis (ABPA) is a complex disease, triggered by a hypersensitivity reaction to Aspergillus fumigatus. The disease diagnosis is difficult, and a major problem is the lack of standardized allergens for the determination of specific antibodies. The aim of the present study is to evaluate if intradermal (ID) tests with analogs of Asp f 1 can aid in the diagnosis and stage assessment of abpa. Three groups of patients classified by serological tests were obtained. 20 ABPA (16BQ+; 4BQ-), 25 possible-ABPA (14BQ+; 11BQ-), 24 asthmatic-ABPAfree (11BQ+; 13BQ-) and 10 asthma-free people were submitted to id tests with three antigens: mitogillin, a-sarcin and restrictocin. There was intense reaction to all three antigens and the response was similar. The positive reactions to mitogillin were biopsied. The skin biopsies of two (12,5%) bq+ patients of the first group and 5 BQ+ (35,6%) patients of the second one showed vasculitis by immune complexes (IC) deposition. 11 patients of the third group had negative biopsies. The fourth group didn\'t have late-reaction. All patients with positive reaction were BQ+. By ID test, alfa-sarcin, mitogillin and restrictocin could differentiate patients with abpa and can be applicable in disease diagnosis. The higher incidence of bronchiectasis was found in the first (80%) and second (56%) groups. In the third group, IC wasn\'t found in 23 asthma patients and id test was positive to A. fumigatus. All patients with vasculitis by IC had bronchiectasis. Therefore, the results indicate that this kind of pulmonary lesion is caused by vasculitis.