Being among the most prevalent of persistent infectious agents in humans worldwide, Helicobacter pylori induces chronic inflammation (gastritis), which may progress to peptic ulceration and stomach cancer. The ability to adhere to the gastric mucosa is considered to be both a colonization and virulence property of H. pylori. For adherence, H. pylori expresses surface-located attachment proteins (adhesins) that bind to specific receptors in the gastric mucosa. The best characterized H. pylori adhesin-receptor interaction is that between the blood group antigen binding adhesin (BabA) and the fucosylated blood group antigens, which are glycans highly expressed in the gastric mucosa. Our recent results have changed the view of the blood group antigen-specific binding mode of H. pylori. We have tested clinical isolates of H. pylori from human populations worldwide for their ability to bind to ABO blood group antigens. The results revealed that more than 95% of isolates from Sweden, Germany, Spain, Japan and Alaska that bind fucosylated blood group antigens, bind both the Lewis b antigen (Leb) (of blood group O) and the blood group A-related antigen A-Lewis b, i.e. they exhibit a generalist type of binding mode. In contrast, the majority of strains (62%) from South American Amerindians bound best to Leb, i.e. they exhibit a specialist blood group “O antigen” binding mode. This specialization in binding coincides with the unique predominance of blood group O in the South American Amerindian populations. Furthermore, we also showed that H. pylori could switch from specialist to generalist binding modes by chromosomal integration of foreign babA gene fragments. A mutant strain lacking the babA gene turned out to adhere to inflamed gastric epithelium, despite the fact that it did not bind Leb. We identified the receptor to which the mutant binds to as the sialyl-dimeric-Lewis x antigen (sdiLex) and found its expression to be associated with persistent H. pylori infection and chronic inflammation, both in humans and Rhesus monkeys. The cognate sialic acid binding adhesin (SabA) was identified by our ReTagging technique. Deletion of sabA caused loss of H. pylori binding to sialylated glycans, and screening of single colony isolates revealed a high frequency of spontaneous on⇒off phase variation in sLex binding. Using erythrocytes as a model for sialyl dependent cell adhesion, we could show that SabA is the sought-after H. pylori sialyl-dependent hemagglutinin. Swedish clinical H. pylori isolates were analyzed for sialyl-dependent hemagglutination (sia-HA), and the sia-HA titers were found to be highly correlated to the levels of sLex binding. Clinical isolates were shown to exhibit several distinct binding modes for sialylated glycans, which suggest that SabA exhibit polymorphism in binding. We also found that SabA binds to sialylated glycans on neutrophil surfaces by mechanisms involving “selectin mimicry”, and that SabA plays an important role in nonopsonic activation of neutrophils. In the human stomach, H. pylori is exposed to selective pressures such as immune and inflammatory responses, and this is reflected by changes in mucosal glycosylation patterns. The high mutation and recombination rates of H. pylori in combination with bio selection will continuously generate clones that are adapted to changes in individual gastric mucosa. Such adaptive selection contributes to the remarkable diversity in binding modes and to the extraordinary chronicity of H. pylori infections worldwide.

Diss. (sammanfattning) Göteborg : Univ., 2009. / Härtill 4 uppsatser.

Orientador: Andrei Moroz / Resumo: As membranas de hemácias e leucócitos são compostas por centenas de antígenos que desempenham diversas funções relacionadas a homeostase, metabolismo celular e podem estar envolvidos em processos de rejeição de transplantes, doenças hemolíticas e reações transfusionais. Para a detecção desses antígenos são utilizados anticorpos monoclonais e a obtenção destes anticorpos envolve diversas etapas que culminam na caracterização dos produtos obtidos. Esta etapa é crítica e envolve diferentes técnicas, incluindo a Proteômica na descrição da proteína-alvo de cada anticorpo monoclonal. O objetivo deste estudo foi caracterizar anticorpos monoclonais de especificidade anti-eritrocitária e anti-leucocitária produzidos pelo Laboratório de Engenharia Celular (LEC) do Hemocentro de Botucatu. Foram selecionados um clone e um hibridoma produtores de anticorpos anti-eritrocitários, e um clone produtor de anticorpos anti-leucocitários, pertencentes ao banco de células do LEC. As células foram expandidas em cultura, foi realizado Western Blotting (WB) e cada banda proteica reconhecida pelos anticorpos (antígenos) foi analisada por Espectrometria de Massas, segundo técnicas proteômicas. Outros testes adicionais foram realizados, como técnicas imuno-hematológicas, citometria de fluxo e imuno-histoquímica. Após expansão, retestagem e verificação de reatividade contra hemácias humanas, e a seleção dos dados de outros estudos até então não explorados, na técnica de WB os anticorpos reconheceram dive... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Red blood cell and leukocyte membranes are composed of hundreds of antigens that perform various functions related to homeostasis, cell metabolism and may be involved in transplant rejection, hemolytic disease and transfusion reactions. Monoclonal antibodies are used to detect these antigens and the obtaining of these antibodies involves several steps that culminate in the characterization of the obtained products. This step is critical and involves different techniques, including Proteomics to descript the target protein of each monoclonal antibody. The aim of this study was to characterize anti-erythrocyte and anti-leukocyte monoclonal antibodies produced by the Laboratory of Cellular Engineering (LEC) of the Blood Center of Botucatu. Anti-erythrocytes clone and hybridoma antibody producers and a clone that produces anti-leukocyte antibodies, belonging to the LEC cell bank were selected. Cells were expanded in culture, it was realyzed Western Blotting (WB) technique and each protein band recognized by the antibodies (antigens) was analyzed by Mass Spectrometry according to proteomic techniques. Others tests were realized, such as immunohematology techniques, flow cytometry and immunohistochemistry. After expansion, retesting and verification of reactivity against human red blood cells, and selection of data from other studies not exploited, in the WB technique, the antibodies recognized several spots. After analysis by Mass Spectrometry, it was identified, with good reliabi... (Complete abstract click electronic access below) / Mestre

Submitted by ALINE TROMBINI RODRIGUES null (aline.trombini.rodrigues@hotmail.com) on 2016-04-05T00:19:31Z No. of bitstreams: 1 Dissertação Aline Trombini Rodrigues.pdf: 2179862 bytes, checksum: 92ed01e81ff3781b11363c36b0c2268f (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-06T16:56:46Z (GMT) No. of bitstreams: 1 rodrigues_at_me_bot.pdf: 2179862 bytes, checksum: 92ed01e81ff3781b11363c36b0c2268f (MD5) / Made available in DSpace on 2016-04-06T16:56:46Z (GMT). No. of bitstreams: 1 rodrigues_at_me_bot.pdf: 2179862 bytes, checksum: 92ed01e81ff3781b11363c36b0c2268f (MD5) Previous issue date: 2016-02-24 / O conhecimento dos fenótipos eritrocitários de doadores de sangue é um procedimento essencial na prática transfusional, o qual aumenta a eficácia e a segurança do ato transfusional, além de prevenir a aloimunização. Os antígenos eritrocitários são clinicamente significantes na medicina transfusional, por serem altamente imunogênicos e pela possibilidade de causarem reações transfusionais, aloimunizações, anemias hemolíticas autoimunes e doença hemolítica do feto e recém-nascido (DHFRN). A incidência de aloimunização à antígenos eritrocitários é alta em pacientes politransfundidos, principalmente nos portadores de hemoglobinopatias e em pacientes submetidos a transplantes. O objetivo deste trabalho foi elaborar um banco de doadores de hemácias com diferentes fenótipos e painéis contendo soros e plasmas com anticorpos de importância clínica para atender e agilizar a transfusão de receptores de sangue alossensibilizados. Foi realizado um levantamento dos doadores de sangue do Hemocentro de Botucatu fenotipados utilizando registros de livros de bancada do ano de 2001 a 2007 e do sistema informatizado (Sistema de Banco de Sangue – SBS), através do qual encontramos um total de 6.039 doadores fenotipados, sendo que 2.700 tinham apenas registro nos livros de bancada. Das 31.942 amostras de doadores de sangue em que foram realizadas a Pesquisa de Anticorpos Irregulares (PAI) no período do nosso estudo, 77 apresentaram a PAI positiva na rotina laboratorial. Para a elaboração do Banco de Doadores Fenotipados, foram cadastrados e validados (duas ou mais fenotipagens realizadas) no sistema informatizado SBS, 7.074 antígenos de todos os sistemas de grupos sanguíneos. Desses, 4.748 (67,1%) antígenos pertenciam ao sistema Rh e 2.326 (32,9%) pertenciam a outros sistemas de grupos sanguíneos. Dos antígenos cadastrados (7.074), 2.396 (89%) antígenos não tinham nenhum histórico de fenotipagens anteriores e 304 (11%) já possuíam histórico e foram validados. De um total de 31.942 doadores de sangue, 77 apresentaram a PAI positiva. Para elaboração da soroteca/plasmateca constituída por painéis de soros/plasmas raros, realizamos novamente a PAI dessas amostras, seguida da Identificação de Anticorpos Irregulares (IAI), do tratamento com Dithiothreitol (DTT), se necessário, e da titulação de anticorpos. Destas 77 amostras de PAI positiva, 21 constituíram a soroteca/plasmateca, pois consideramos como critérios de inclusão: a importância clínica, a especificidade e o título dos anticorpos (reatividade com diluição maior que 1/2). Do total de anticorpos identificados (77), os de maior prevalência foram: anti-D, anti-E, anti-Dia, anti-M, anti-D+C e anti-Lea. Assim sendo, concluímos que é de suma importância a elaboração de um Banco de Doadores de Sangue com fenótipos menos frequentes, para que os pacientes em esquema de transfusão de concentrado de hemácias possam ser transfundidos de modo mais compatível possível, prevenindo deste assim a aloimunização a antígenos eritrocitários e otimizando a prática transfusional. É essencial também a elaboração de uma soroteca/plasmateca constituída de painéis de soros/plasma com anticorpos de importância clínica e, com isso, proporcionar além de uma maior agilidade na triagem da bolsa de concentrado de hemácias compatível, uma maior segurança para o paciente transfundido. / The knowledge of the erythrocyte phenotypes of blood donors is an essential procedure in transfusion practice, which increases the effectiveness and safety of transfusion Act, besides preventing the aloimunização. Erythrocyte antigens are clinically significant in transfusion medicine, because they are highly imunogênicos and the possibility of causing transfusional reactions, autoimmune hemolytic anemia, aloimunizações and hemolytic disease of the fetus and newborn (DHFRN). The incidence of alloimmunization to the erythrocyte antigens is high into politransfundidos patients, especially in patients with hemoglobinopathies and in patients undergoing organ transplants. The aim of this work was to develop a bank of red blood donors with different phenotypes and panels containing serums and plasmas with antibodies of clinical importance to attend and simplify the transfusion of blood alossensibilizados receivers. We manage a survey of blood donors from the Blood of Botucatu, using bench books records of the year 2001 to 2007 and computerised system (blood bank system SBS), through which we found a total of 6039 donors in conclusion, which only 2700 had records on the books. A total of samples (31942) of blood donors that were collected from the research of irregular antibodies (RAI) during the period of our study, 77 presented the RAI in laboratory routine. For the preparation of the donor bank in conclusion have been registered and validated (two or more fenotipagens made) in the computerised system SBS, 7074 antigens in every system of blood groups. Of these, 4748 (67.1) antigens belonged to the Rh system and 2326 (32.9) belonged to other blood group systems. Of registered antigens (7,074), 2396 (89) antigens had no history of previous fenotipagens and 304 (11) already had a history and have been validated. A total of 77 31942, blood donors showed the positive RAI. For the preparation of sorotecaplasmateca consisting of sorosplasmas rare panels carry out again the RAI of those samples, followed by the identification of irregular antibodies (IAI), treatment with Dithiothreitol (DTT) if necessary and titration of antibodies. Of these 77 samples were positive RAI, 21 formed the sorotecaplasmateca, because we believe as inclusion criteria: the clinical importance, the specificity and the title of antibodies (reactivity with dilution greater than 1/2). A total of identified antibodies (77), the most prevalent were: anti-D, anti-E, anti-Dia, anti-M, anti-D+C e anti-Lea . Therefore, we conclude that it is of the utmost importance to develop a Bank of blood donors with less frequent phenotypes, so that patients in transfusion of packed red blood cells, can be transfused as compatible as possible, preventing the alloimmunization to erythrocyte antigens and optimizing transfusion practice. It is essential also to draw up a sorotecaplasmateca consisting of sorosplasma panels with antibodies of clinical importance, for in this way we provide in addition to greater agility in the scholarship screening of packed cells compatible, greater safety for the patient transfused.

Orientador: Valéria Nogueira Dias Paes Secco / Resumo: O conhecimento dos fenótipos eritrocitários de doadores de sangue é um procedimento essencial na prática transfusional, o qual aumenta a eficácia e a segurança do ato transfusional, além de prevenir a aloimunização. Os antígenos eritrocitários são clinicamente significantes na medicina transfusional, por serem altamente imunogênicos e pela possibilidade de causarem reações transfusionais, aloimunizações, anemias hemolíticas autoimunes e doença hemolítica do feto e recém-nascido (DHFRN). A incidência de aloimunização à antígenos eritrocitários é alta em pacientes politransfundidos, principalmente nos portadores de hemoglobinopatias e em pacientes submetidos a transplantes. O objetivo deste trabalho foi elaborar um banco de doadores de hemácias com diferentes fenótipos e painéis contendo soros e plasmas com anticorpos de importância clínica para atender e agilizar a transfusão de receptores de sangue alossensibilizados. Foi realizado um levantamento dos doadores de sangue do Hemocentro de Botucatu fenotipados utilizando registros de livros de bancada do ano de 2001 a 2007 e do sistema informatizado (Sistema de Banco de Sangue – SBS), através do qual encontramos um total de 6.039 doadores fenotipados, sendo que 2.700 tinham apenas registro nos livros de bancada. Das 31.942 amostras de doadores de sangue em que foram realizadas a Pesquisa de Anticorpos Irregulares (PAI) no período do nosso estudo, 77 apresentaram a PAI positiva na rotina laboratorial. Para a elaboração do Banco d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The knowledge of the erythrocyte phenotypes of blood donors is an essential procedure in transfusion practice, which increases the effectiveness and safety of transfusion Act, besides preventing the aloimunização. Erythrocyte antigens are clinically significant in transfusion medicine, because they are highly imunogênicos and the possibility of causing transfusional reactions, autoimmune hemolytic anemia, aloimunizações and hemolytic disease of the fetus and newborn (DHFRN). The incidence of alloimmunization to the erythrocyte antigens is high into politransfundidos patients, especially in patients with hemoglobinopathies and in patients undergoing organ transplants. The aim of this work was to develop a bank of red blood donors with different phenotypes and panels containing serums and plasmas with antibodies of clinical importance to attend and simplify the transfusion of blood alossensibilizados receivers. We manage a survey of blood donors from the Blood of Botucatu, using bench books records of the year 2001 to 2007 and computerised system (blood bank system SBS), through which we found a total of 6039 donors in conclusion, which only 2700 had records on the books. A total of samples (31942) of blood donors that were collected from the research of irregular antibodies (RAI) during the period of our study, 77 presented the RAI in laboratory routine. For the preparation of the donor bank in conclusion have been registered and validated (two or more fenotipagens made) in th... (Complete abstract click electronic access below) / Mestre

No description available.

Viruses are common causes of both endemic and epidemic gastroenteritis, infecting millions of people per year, with norovirus, rotavirus and adenovirus-F as the main causative agents, and sapovirus and astrovirus as contributing viruses. These viruses are highly infectious and most severe in the very young, old, or individuals who are immunocompromised. The viral infection usually causes self-limited gastroenteritis, although chronic infection has been observed in highly immunocompromised patients. African and South-East Asian regions are disproportionally affected by diarrhoeal disease. These regions (especially South Africa) are also more severely affected by human immunodeficiency virus (HIV) infections. It has been suggested that immunocompromised individuals may form part of a reservoir for novel virus variants and recombinants. It should be taken into account that not every person is equally susceptible to infection after pathogen exposure and that not all infected persons develop clinical symptoms (Ramani and Giri, 2019). One host genetic factor that can influence susceptibility to enteric infection is the expression of histo-blood group antigens (HBGAs). Histo-blood group antigens are a major group of complex carbohydrates and are determinants of both human and animal ABO blood groups and the Lewis blood group systems, which are distributed in abundance on the mucosal epithelia of the gastrointestinal tract. Histo-blood group antigens have been proven to influence susceptibility to rotavirus and norovirus infections. Saliva, blood and stool specimens (n=205) have previously been collected from children (≤ 5 years of age) hospitalised with gastroenteritis at Kalafong Provincial Tertiary Hospital from June 2016 to December 2017. Follow up stool specimens were then collected six weeks after enrolment when possible. A descriptive questionnaire was completed by each child’s guardian, giving information on age, residential area, HIV status etc. of the participating child. The stool specimens were screened for six gastroenteritis causing viruses (norovirus GI and –GII, rotavirus, sapovirus, astrovirus and adenovirus) by multiplex PCR. Forty-seven percent (96/205) of specimens tested positive for at least one gastroenteritis causing virus. Rotavirus predominated (46/205), followed by norovirus (32/205), adenovirus (15/205), sapovirus (9/205) and astrovirus (3/205). A total of 27/32 norovirus (GI.3, GII.2, GII.3, GII.4, GII.7, GII.12 and GII.21), 44/46 rotavirus (G1P[8], G2P[4], G2P[6], G3P[4], G3P[8], G8P[4], G8P[6], G9P[6] and G9P[8]) and 8/9 sapovirus (GI.1, GI.2, GII.1, GII.4 and GII.8) strains have been genotyped, of which norovirus GII.4 and rotavirus G3P[4] predominated. A total of 46/205 children submitted a follow up stool specimen to be tested. Of the 46 children, 9 tested positive for norovirus infection with initial stool specimen testing. Follow up screening resulted in 13/46 (28%) specimens testing positive for either norovirus GI or GII, with all patients presenting as asymptomatic. After genotyping it was observed that only one of the follow up specimens were identical to the original sequence genotyped, indicating prolonged shedding. FUT2 genotyping of 205/205 children showed a 71%:29% ratio between secretors and non-secretors. Eighty percent (77/96) of the virus-infected children were secretors whereas only 20% (19/96) were non-secretors. Rotavirus (p<0.01) and norovirus GII.4 (p<0.05) specifically were found to be more prevalent in secretors. In this study, no statistical significance was observed in terms of severity of and susceptibility to gastroenteritis viruses between HIV-infected, HIV-exposed uninfected or HIV-uninfected individuals. Histo-blood group phenotyping has resulted in various combinations, with Le(b) being the most prevalent antigen found. Next generation sequencing was unsuccessful. In future, fresh specimens should be considered for testing, with more funding and time for optimisation of this process and to give adequate results. In summary, gastroenteritis is still a leading cause of childhood morbidity and mortality, with all advancements in understanding the disease helping to decrease the impact of it. This study again reinforced the importance of these viruses, as they are circulating in such high abundance. It also reinforced the concept that susceptibility to noro- and rotavirus infection is affected by the secretor status of a person. This could in future help with better understanding the viral infection mechanisms and in turn help with vaccine development and treatment / Dissertation (MSc (Medical Virology))--University of Pretoria, 2020. / Reese Mushrooms / Discovery grant / PRF / Medical Virology / Msc / Unrestricted

Orientadores: Lilian Maria de Castilho, Jeane Eliete Laguila Visentainer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T13:14:12Z (GMT). No. of bitstreams: 1 Guelsin_GlauciaAndreiaSoares_D.pdf: 3524338 bytes, checksum: 77312cdc47d244e00235a67d7f52c666 (MD5) Previous issue date: 2014 / Resumo: A síndrome mielosplásica (SMD) correponde a um grupo de distúrbios clonais heterogêneos decorrente de um defeito intrínseco das células progenitoras hematopoéticas, resultando em insuficiência da medula óssea, desencadeando anemia com dependência de transfusões sanguíneas e infecções decorrentes da neutropenia. Embora a terapia transfusional seja segura, muitos desses pacientes correm risco de complicações relacionadas à sobrecarga de ferro e à aloimunização contra antígenos de grupos sanguíneos, que muitas vezes dificulta a busca de sangue compatível para esses pacientes, além estar associada a reações hemolíticas transfusionais tardias e formação de auto-anticorpos. A compatibilidade para antígenos Rh e K tem sido utilizada na tentativa de reduzir a formação de anticorpos em pacientes que recebem transfusões crônicas, mas a fenotipagem estendida, incluindo os antígenos Fya e Jka, também tem sido recomendada. Este estudo teve como objetivos avaliar o perfil transfusional dos pacientes com SMD, propor um protocolo de compatibilidade molecular para seleção de sangue fenótipo compatível e avaliar uma possível associação dos alelos HLA com a susceptibilidade ou proteção a aloimunização eritrocitária. Foram analisados 61 pacientes portadores de SMD, sendo 18 pacientes não transfundidos e 43 pacientes submetidos à terapia transfusional com e sem formação de anticorpos. Realizamos genotipagem para os alelos de grupos sanguíneos RHD, RHCE, FY, DO, CO, DI, SC, GYPA, GYPB, LU, KEL, JK e LW e para os alelos HLA classe I e classe II nas amostras dos pacientes e comparamos os resultados com grupos- controle. Com relação ao perfil transfusional dos pacientes estudados, a maioria recebe transfusões sanguíneas regulares e 44% encontra-se aloimunizada. Os principais aloanticorpos detectados foram contra antígenos Rh e K. Verificamos que a genotipagem é superior a fenotipagem para determinação dos antígenos de grupos sanguíneos e que a compatibilidade molecular para Rh e K seria suficiente para evitar a aloimunização eritrocitária na maioria dos pacientes. Nossos resultados também mostraram uma associação entre o alelo HLA-DRB1*13 e a proteção à aloimunização contra antígenos de grupos sanguíneos em pacientes com SMD / Abstract: The myelodysplastic syndrome (MDS) is a group of heterogeneous clonal disorder caused by an intrinsic stem cell defect with propensity to the bone marrow failure that results in the transfusion dependence and neutropenic infection. Although blood transfusion is generally safe, many of those patients are at risk of transfusion-related complications such as iron overload and RBC alloimmunization that often makes finding compatible RBC products difficult and is also associated with delayed hemolytic transfusion reactions (DHTRs) and autoantibody formation. Matching for Rh and K antigens has been used in an attempt to reduce antibody formation in patients receiving chronic transfusions but an extended phenotyping matching including Fya and Jka antigens has also been recommended. This study was aimed to identify the transfusion profile of the patients with myelodysplastic syndrome (MDS), an efficient transfusion protocol of genotype matching and a possible association of HLA class alleles with susceptibility or protection to RBC alloimmunization. We evaluated 61 patients with MDS, 18 not transfused and 43 undergoing transfusion therapy with and without antibody formation. We performed genotyping for RHD, RHCE, FY, DO, CO, DI, SC, GYPA, GYPB, LU, KEL, JK e LW and for HLA class I and class II alleles in the patient DNA samples and compared the results with a control group. We verified that the majority of patients have regular transfusions and 44% are alloimmunized to RBC antigens. Blood group genotyping was superior to phenotyping to determine the antigen profile in those patients and molecular matching for Rh and K would be enough for most of the patients. Our results also showed a significant association of HLA-DRB1*13 with protection to RBC alloimmunization in patients with MDS / Doutorado / Clinica Medica / Doutora em Clínica Médica

A hipertensão essencial tem alta prevalência mundial, bem como, causas genéticas e ambientais. Na busca de correlações genéticas para a hipertensão, foi descrito um potencial papel do DARC (Duffy Antigen Receptor of Chemokines) como receptor de Interleucina-8 em endotélio e que essa interação poderia contribuir para a patogênese da pré-eclampsia. O DARC está expresso em vários tecidos além da linhagem eritróide, em especial nas células endoteliais. A glicoproteína DARC carreia determinantes antigênicos e também é receptora para Plasmodium vivax, tendo relevância biológica significante. Esse estudo teve como objetivo estudar a freqüência fenotípica e genotípica do Sistema de Grupo Sangüíneo Duffy comparando pacientes com hipertensão maligna com doadores de sangue normotensos. Foram estudadas 43 amostras de sangue de pacientes com diagnóstico de hipertensão maligna da Unidade de Hipertensão do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. O grupo controle foi constituído por 100 amostras de doadores de sangue da Fundação Pró-Sangue/Hemocentro de São Paulo. Em todas as amostras foi realizada a fenotipagem Duffy, a genotipagem DUFFY e a dosagem de IL-8 sérica. A fenotipagem foi realizada pela técnica em tubo. Na genotipagem DUFFY, foram estudadas as mutações 125G>A, 265C>T, 29 G>A e -33T>C pela técnica de PCR-RFLP. Na análise da freqüência alélica encontramos que o alelo FYB-33 foi o mais observado no grupo de pacientes com hipertensão maligna com diferença estatisticamente significante (p= 0,0191). Conseguimos demonstrar uma correlação entre níveis elevados de IL-8 em pacientes com hipertensão maligna e genótipo FYB- 33/FYB-33 (p=0,003). Também observamos níveis elevados de IL-8 nos pacientes com hipertensão maligna quando comparados com o grupo controle (doadores de sangue), p<0,001. Esses resultados indicam que a IL-8 tem papel potencial na fisiopatologia da hipertensão maligna por apresentar um efeito regulatório inibitório em pacientes Duffy negativo. / Essential hypertension has a high prevalence worldwide and the has genetic and environment causes. Searching genetics correlation for hypertension, a potential role of DARC (Duffy Antigen Receptor of Chemokines) was described as an Interleukine-8 receptor in endothelium and that this interaction might contribute for the pathogenesis of pre-eclampsia. DARC is expressed in many tissues beyond the erythrocyte lineage, in special endothelium cells. DARC glycoprotein carries antigens determinants and is also Plasmodium vivax receptor, with a significantly biological relevance. This study had as objective to verify the phenotypic and genetic frequencies of the Duffy Blood Group System in patients with malignant hypertension and, to compare them with norm tension blood donors. Forty three patients from the Hypertension Service of the InCor of Clinical Hospital of School of Medicine of the University of São Paulo and 100 blood donors from Fundação Pró-Sangue/Hemocentro de São Paulo were studied. Duffy phenotyping and genotyping and IL-8 serum dosage was performed in all samples. Phenotyping tests were performed by tube technique. We studied the 125 G>A, 265 C>T, 298 G>A and -33 T>C mutations by PCR RFLP genotyping. The FYB-33 allele was the most observed in the malignant hypertension patients group with p= 0.0191. We have shown a correlation in high between high levels of IL-8 in patients with malignant hypertension and FYB-33/FYB-33 genotype (p=0,003). We observed also high levels of IL-8 in patients with malignant hypertension when the control group (blood donors) was compared, p<0.001. This results indicate that IL-8 has a potential role in malignant hypertension physiopathology due to an regulatory inhibitory effect in Duffy negative patients.

Les norovirus sont l'une des causes principales de gastroentérite. Depuis 2002, des variants de norovirus GII.4 successifs ont circulé dans la population par cycle de 2-3 ans, ce qui suscite des interrogations quant au rôle de leurs ligands, les antigènes tissulaires de groupes sanguins (HBGA), dans leur évolution. Nous avons analysé l'interaction entre des variants de GII.4 représentatifs et des HBGA, et déterminé le rôle d’acides aminés (aa) clés. Par mutagénèse dirigée, nous avons montré qu’une configuration stricte des aa directement impliqués dans l’accroche est indispensable. La suppression de la thréonine 395, caractéristique des variants après 2002, confère la capacité de se lier à Lex et Si-Lex, démontrant que les aa en dehors du site de liaison peuvent modifier les propriétés d’attachement. L'analyse de l'accroche de VLP de 6 variants isolés de 1987 à 2007 à des échantillons de salive phénotypés et des HBGA synthétiques montre que tous les variants sont capables de s’attacher à la salive des sécréteurs indépendamment du phénotype ABO et aux oligosaccharides propres au phénotype sécréteur. Deux variants récents ont pu également s’accrocher aux sucres présents dans la salive des nonsécréteurs Le(+). Nos données suggèrent que la capacité de se lier à Lex et Si-Lex serait une conséquence de la variation génétique des aa situés à proximité du site de liaison. L'analyse des propriétés d’attachement par résonance plasmonique de surface a montré que seuls les variants après 2002 présentent une affinité forte pour les antigènes A et B, suggérant que l’accélération évolutive des GII.4 pourrait être liée à une affinité accrue des variants pour les HBGA après 2002. / Noroviruses are one of the leading causes of gastroenteritis worldwide. Since 2002 successive GII.4 variants have circulated in the population before being replaced every 2-3 years, which raises questions about the role of their histo-blood group antigen (HBGAs) receptors in their evolution. We analyzed the interaction between representative GII.4 variants and HBGAs and determined the role of selected amino acids (aa) in the binding profiles. By mutagenesis, we showed that there was a strict structural requirement for the aa directly implicated in HBGA bindings. The ablation of the threonine 395 residue, an epidemiological feature of the post 2002 variants, allowed to gain the capacity to bind to the Lewis x and sialyl-Lewis x antigens, demonstrating that aa residues outside the HBGA binding site can modify the binding properties. The analysis of the attachment of VLPs from 6 variants isolated from 1987 to 2007 to phenotyped saliva samples and synthetic HBGAs shows that all variants could attach to saliva of secretors irrespective of the ABO phenotype and to oligosaccharides characteristic of the secretor phenotype. Interestingly, two recent variants additionally bound to carbohydrates present in the saliva of Lewis-positive non-secretors. Our data suggest that GII.4 binding to Lex and Si-Lex antigens might be a by-product of the genetic variation of the aa located in the vicinity of the binding site. Analysis of the binding properties by surface plasmon resonance showed that only post 2002 variants presented a strong affinity for A and B antigens, suggesting that the GII.4 evolution could be related to an increased affinity for HBGAs for the post 2002 variants.