998 resultados para HLA genes
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Background. Hepatitis B virus (HBV) is an important cause of chronic viral disease worldwide and can be life threatening. While a safe and effective vaccine is widely available, 5 to 10% of healthy vaccinees fail to achieve a protective anti-hepatitis B surface antigen antibody (anti-HBs) titer (>10mIU/ml). A limited number of studies investigated host genetics of the response to HBV vaccine. To our knowledge, no comprehensive overview of genetic polymorphisms both within and outside the HLA system has been done so far. Aim. The aim of this study was to perform a systematic review of the literature of human genetics influencing immune response after hepatitis B vaccination. Methods. Literature searches using keywords were conducted in the electronic databases Medline, Embase and ISI Web of Science the cut-off date being March 2014. After selection of papers according to stringent inclusion criteria, relevant information was systematically collected from the remaining articles, including demographic data, number of patients, schedule and type of vaccine, phenotypes, genes and single nucleotide polymorphisms (SNPs) genotyping results and their association with immune response to hepatitis B vaccine. Results. The literature search produced a total of 1968 articles from which 46 studies were kept for further analyses. From these studies, data was extracted for 19 alleles from the human leukocyte antigen (HLA) region that were reported as significant at least twice. Among those alleles, 9 were firmly associated with vaccine response outcome (DQ2 [DQB1*02 and DQB1*0201], DR3 [DRB1*03 and DRB1*0301], DR7 [DRB1*07 and DRB1*0701], C4AQ0, DPB1*0401, DQ3, DQB1*06, DRB1*01 and DRB1*13 [DRB1*1301]). In addition, data was extracted for 55 different genes from which 13 extra-HLA genes had polymorphisms that were studied by different group of investigators or by the same group with a replication study. Among the 13 genes allowing comparison, 4 genes (IL-1B, IL-2, IL-4R and IL- 6) revealed no significant data, 6 genes (IL-4, IL-10, IL-12B, IL-13, TNFA, IFNG and TLR2) were explored with inconsistent results and 2 genes (CD3Z and ITGAL) yielded promising results as their association with vaccine response was confirmed by a replication approach. Furthermore, this review produced a list of 46 SNPs from 26 genes that were associated with immune response to vaccine only once, providing novel candidates to be tested in datasets from existing genome-wide association studies (GWAS). Conclusion. To the best of our knowledge, this is the first systematic review of immunogenetic studies of response to hepatitis B vaccine. While this work reassesses the role of several HLA alleles on vaccine response outcome, the associations with polymorphisms in genes outside the HLA region were rather inconsistent. Moreover, this work produced a list of 46 significant SNPs that were reported by a single group of investigators, opening up some interesting possibilities for further research.
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Les maladies immunitaires chroniques incluant les maladies auto-immunes et inflammatoires touchent 20 à 25% de la population des pays occidentaux. La comparaison des taux de concordance chez les jumeaux ou l’histoire familiale de sujets atteints de la maladie cœliaque (maladie auto-immune de l’intestin) ou de l’œsophagite éosinophilique (maladie inflammatoire de l’œsophage) indiquent que des facteurs génétiques et environnementaux interviennent dans la susceptibilité à ces maladies. Cependant, ces études ne distinguent pas de manière claire la prédisposition génétique selon l’hétérogénéité clinique (enfants versus adultes) ou ethnique (stratification des populations). Méthodes. Les haplotypes HLA de prédisposition à la maladie cœliaque et les polymorphismes des gènes candidats IL-13 (R130Q), IL-5 (-746 T/G) et IL-5R (-80A/G) impliqués dans la physiopathologie de l’œsophagite éosinophilique, ont été caractérisés par la technique PCR-SSP sur l’ADN génomique. Résultats: Nos études familiales et cas-contrôles réalisées chez une population Québécoises avec un fond génétique très homogène nous a permis : i) d’éviter le problème de stratification des populations, ii) de confirmer que les gènes HLA sont également associés à la maladie cœliaque (enfants et adultes) au Québec comme dans les autres populations Caucasiennes, iii) de mettre en évidence le rôle du gène IL-13 dans la prédisposition à l’œsophagite éosinophilique (garçons et filles) et d’exclure les gènes IL-5 et IL-5R comme facteurs de susceptibilité dans notre population. Conclusion: Ce travail confirme pour la première fois l’impact des gènes HLA dans la prédisposition à la maladie cœliaque et le rôle du facteur génétique dans l’œsophagite éosinophilique chez une population Canadienne Française avec un fond génétique ayant un fort effet fondateur.
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Objetivos: Determinar la prevalencia y los factores asociados con el desarrollo de hipotiroidismo autoinmune (HA) en una cohorte de pacientes con lupus eritematoso sistémico (LES), y analizar la información actual en cuanto a la prevalencia e impacto de la enfermedad tiroidea autoinmune y la autoinmunidad tiroidea en pacientes con LES. Métodos: Este fue un estudio realizado en dos pasos. Primero, un total de 376 pacientes con LES fueron evaluados sistemáticamente por la presencia de: 1) HA confirmado, 2) positividad para anticuerpos tiroperoxidasa/tiroglobulina (TPOAb/TgAb) sin hipotiroidismo, 3) hipotiroidismo no autoinmune, y 4) pacientes con LES sin hipotiroidismo ni positividad para TPOAb/TgAb. Se construyeron modelos multivariados y árboles de regresión y clasificación para analizar los datos. Segundo, la información actual fue evaluada a través de una revisión sistemática de la literatura (RLS). Se siguieron las guías PRISMA para la búsqueda en las bases de datos PubMed, Scopus, SciELO y Librería Virtual en Salud. Resultados: En nuestra cohorte, la prevalencia de HA confirmado fue de 12% (Grupo 1). Sin embargo, la frecuencia de positividad para TPOAb y TgAb fue de 21% y 10%, respectivamente (Grupo 2). Los pacientes con LES sin HA, hipotiroidismo no autoinmune ni positividad para TPOAb/TgAb constituyeron el 40% de la corhorte. Los pacientes con HA confirmada fueron estadísticamente significativo de mayor edad y tuvieron un inicio tardío de la enfermedad. El tabaquismo (ORA 6.93, IC 95% 1.98-28.54, p= 0.004), la presencia de Síndrome de Sjögren (SS) (ORA 23.2, IC 95% 1.89-359.53, p= 0.015) y la positividad para anticuerpos anti-péptido cíclico citrulinado (anti-CCP) (ORA 10.35, IC 95% 1.04-121.26, p= 0.047) se asociaron con la coexistencia de LES-HA, ajustado por género y duración de la enfermedad. El tabaquismo y el SS fueron confirmados como factores predictivos para LES-HA (AUC del modelo CART = 0.72). En la RSL, la prevalencia de ETA en LES varío entre 1% al 60%. Los factores asociados con esta poliautoinmunidad fueron el género femenino, edad avanzada, tabaquismo, positividad para algunos anticuerpos, SS y el compromiso articular y cutáneo. Conclusiones: La ETA es frecuente en pacientes con LES, y no afecta la severidad del LES. Los factores de riesgo identificados ayudarán a los clínicos en la búsqueda de ETA. Nuestros resultados deben estimular políticas para la suspensión del tabaquismo en pacientes con LES.
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Epidermodysplasia verruciformis (EV) is triggered by a variety of mechanisms that at least partly include genetic background. We present a Brazilian man with a 30-year history of flat, wart-like lesions with clinical, histopathological, and evolutive aspects consistent with papillomavirus (HPV)-associated EV. Histological analysis of the wart lesions showed epidermis with hyperkeratosis, regular acanthosis, hypergranulosis, and cells with abundant basophilic cytoplasm. Moreover, a perivascular lymphocytic infiltrate was found in the superficial dermis, consistent with a viral wart. Type-2-HPV DNA was detected in various fragments of skin-wart lesions using the polymerase chain reaction (PCR). Two years after the EV diagnosis, the patient presented with an anesthetic well-demarcated, erythematous and mildly scaly plaque on his right forearm. A histopathological analysis of this lesion demonstrated the presence of a compact tuberculoid granuloma. Ziehl-Neelsen staining demonstrated the presence of rare acid-fast bacilli and confirmed the tuberculoid leprosy diagnosis. The patient's Mitsuda Intradermal Reaction was positive. To elucidate the possible mechanism involved in this case of EV, we genotyped the HLA genes of this patient. DQB genotyping showed the polymorphic HLA alleles DQB1*0301 and 0501. The patient was treated with a paucibacillary multidrug therapy scheme, and the disease was cured in six months. This report describes an EV patient with an M. leprae infection, confirming that tuberculoid leprosy patients possess a relatively specific and efficient cell-mediated immunity against the bacillus and, therefore, localized forms of the disease. Moreover, we show the possible involvement of the polymorphic HLA alleles DQB1*0301 and 0501 in EV induction mechanisms.
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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB
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In ecology, "disease tolerance" is defined as an evolutionary strategy of hosts against pathogens, characterized by reduced or absent pathogenesis despite high pathogen load. To our knowledge, tolerance has to date not been quantified and disentangled from host resistance to disease in any clinically relevant human infection. Using data from the Swiss HIV Cohort Study, we investigated if there is variation in tolerance to HIV in humans and if this variation is associated with polymorphisms in the human genome. In particular, we tested for associations between tolerance and alleles of the Human Leukocyte Antigen (HLA) genes, the CC chemokine receptor 5 (CCR5), the age at which individuals were infected, and their sex. We found that HLA-B alleles associated with better HIV control do not confer tolerance. The slower disease progression associated with these alleles can be fully attributed to the extent of viral load reduction in carriers. However, we observed that tolerance significantly varies across HLA-B genotypes with a relative standard deviation of 34%. Furthermore, we found that HLA-B homozygotes are less tolerant than heterozygotes. Lastly, tolerance was observed to decrease with age, resulting in a 1.7-fold difference in disease progression between 20 and 60-y-old individuals with the same viral load. Thus, disease tolerance is a feature of infection with HIV, and the identification of the mechanisms involved may pave the way to a better understanding of pathogenesis.
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: To assess in a cohort of Caucasian patients exposed to stavudine (d4T) the association of polymorphisms in pyrimidine pathway enzymes and HLA-B*4001 carriage with HIV lipodystrophy syndrome (HALS). 336 patients, 187 with HALS and 149 without HALS, and 72 controls were recruited. HALS was associated with the presence of a low expression, thymidylate synthase (TS) genotype polymorphism. Methylene-tetrahydrofolate reductase (MTHFR) gene polymorphisms and HLA-B*4001 carriage were not associated with HALS or d4T-TP intracellular levels. In conclusion HALS is associated with combined low-expression TS and MTHFR associated with high activity polymorphisms but not with HLA-B*4001 carriage.
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Tyypin 1 diabeteksen perinnöllinen alttius Suomessa - HLA-alueen ulkopuolisten alttiuslokusten IDDM2 ja IDDM9 rooli taudin periytymisessä HLA-alue, joka sijaitsee kromosomissa 6p21.3, vastaa noin puolesta perinnöllisestä alttiudesta sairastua tyypin 1 diabetekseen. Myös HLA-alueen ulkopuolisten lokusten on todettu liittyvän sairausalttiuteen. Näistä kolmen lokuksen on varmistettu olevan todellisia alttiuslokuksia ja lisäksi useiden muiden, vielä varmistamattomien lokusten, on todettu liittyvän sairausalttiuteen. Tässä tutkimuksessa 12:n HLA-alueen ulkopuolisen alttiuslokuksen kytkentä tyypin 1 diabetekseen tutkittiin käyttäen 107:aa suomalaista multiplex-perhettä. Jatkotutkimuksessa analysoitiin IDDM9-alueen kytkentä ja assosiaatio sairauteen laajennetuissa perhemateriaaleissa sekä IDDM2-alueen mahdollinen interaktio HLA-alueen kanssa sairauden muodostumisessa. Lisäksi suoritettiin IDDM2-alueen suojaavien haplotyyppien alatyypitys tarkoituksena tutkia eri haplotyyppien käyttökelpoisuutta sairastumisriskin tarkempaa ennustamista varten. Ensimmäisessä kytkentätutkimuksessa ei löytynyt koko genomin tasolla merkitsevää tai viitteellistä kytkentää tutkituista HLA-alueen ulkopuolisista lokuksista. Voimakkain havaittu nimellisen merkitsevyyden tavoittava kytkentä nähtiin IDDM9-alueen markkerilla D3S3576 (MLS=1.05). Tutkimuksessa ei kyetty varmistamaan tai sulkemaan pois aiempia kytkentähavaintoja tutkituilla lokuksilla, mutta IDDM9-alueen jatkotutkimuksessa havaittu voimakas kytkentä (MLS=3.4) ja merkitsevä assosiaatio (TDT p=0.0002) viittaa vahvasti siihen, että 3q21-alueella sijaitsee todellinen tyypin 1 diabeteksen alttiusgeeni, jolloin alueen kattava assosiaatiotutkimus olisi perusteltu jatkotoimenpide. Sairauteen altistava IDDM2-alueen MspI-2221 genotyyppi CC oli nimellisesti yleisempi matalan tai kohtalaisen HLA-sairastumisriskin diabeetikoilla, verrattuna korkean HLA-riskin potilaisiin (p=0.05). Myös genotyyppijakauman vertailu osoitti merkitsevää eroa ryhmien välillä (p=0.01). VNTR-haplotyyppitutkimus osoitti, että IIIA/IIIA-homotsygootin sairaudelta suojaava vaikutus on merkitsevästi voimakkaampi kuin muiden luokka III:n genotyypeillä. Nämä tulokset viittaavat IDDM2-HLA -vuorovaikutukseen sekä siihen että IDDM2-alueen haplotyyppien välillä esiintyy etiologista heterogeniaa. Tämän johdosta IDDM2-alueen haplotyyppien tarkempi määrittäminen voisi tehostaa tyypin 1 diabeteksen riskiarviointia.
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INTRODUÇÃO: O vírus linfotrópico para células T humanas (HTLV-1) é o principal agente causador da Paraparesia Espástica Tropical / Mielopatia associada ao HTLV-1 (PET/MAH) e da Leucemia da célula T do Adulto (LTA). A maioria dos indivíduos infectados permanece assintomática, somente 2 a 5% irão desenvolver uma das duas doenças. Fatores da interação HTLV-1/ hospedeiro estão envolvidos no risco de desenvolver doença. A lesão neurológica na PET/MAH parece ser consequência de uma reação inflamatória, desencadeada pelo reconhecimento de células infectadas por linfócitos T citotóxicos, com consequente liberação de citocinas e lesão medular. OBJETIVO: Identificar marcadores genéticos, que possam ajudar no prognóstico e tratamento dos pacientes portadores do HTLV-1. MÉTODOS: Nas amostras de 117 portadores do HTLV-1 assintomáticos e 171 pacientes com acometimento neurológico em acompanhamento na cidade do Rio de Janeiro, foram realizadas as tipificações dos genes do HLA Classe I e II, dos polimorfismos dos genes das citocinas -308TNF-\03B1,-174IL-6, +874IFN-\03B3, códon 10 e 25TGF-\03B21 e -1082 - 819-592IL-10, e a quantificação da carga proviral. Os dados foram organizados em um banco de dados no programa SPSS. As frequências alélicas e genotípicas foram obtidas por contagem direta. O equilíbrio de Hardy-Weinberg foi avaliado para os polimorfismos das citocinas no sitio http://bioinfo.iconcologia.net/ubbweb/SNPStats_web, em relação ao HLA foram utilizadas as ferramentas disponíveis no sítio \201CLos Alamos HIV database tools\201D. As comparações entre os grupos foram realizadas através de tabelas de contingência 2x2 (quiquadrado, exato de Fisher e odds ratios), valores de p\22640,05 foram considerados significantes RESULTADOS E CONCLUSÕES: O alelo A*02 não influencia a condição clínica nem os níveis da carga proviral. Os alelos A*29 e B*44 foram mais frequentes entre os indivíduos assintomáticos e a sua presença influenciou os níveis da carga proviral sugerindo proteção ao desenvolvimento de doença neurológica. O alelo A*68 foi mais frequente entre os pacientes com doença neurológica, porém sua presença não influenciou nos níveis da carga proviral. O alelo C*04 foi mais frequente entre os portadores assintomáticos e não influenciou os níveis de carga proviral, já o alelo DRB1*03 predominou entre os pacientes com doença neurológica e a sua presença entre os indivíduos assintomáticos acarretou níveis mais elevados de carga proviral, sugerindo ser um possível fator de risco para o desenvolvimento de doença neurológica. Na análise do polimorfismo genético das citocinas, o polimorfismo de IL-10, com perfil fenotípico de baixo produtor da citocina foi mais frequente no grupo dos assintomáticos, enquanto que o fenótipo de produtor intermediário predominou entre os sintomáticos. O perfil fenotípico da população estudada foi caracterizado como: baixo produtor da citocina -308TNF-\03B1, intermediário a alto produtor para códon 10 e códon 25 TGF-\03B2, baixo a intermediário produtor para -1082,-819,- 592 IL-10, alto produtor para -174 IL-6 e baixo a intermediário produtor para +874IFN-\03B3
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The non-classical human leukocyte antigen (HLA) class I genes present a very low rate of variation. So far, only 10 HLA-E alleles encoding three proteins have been described, but only two are frequently found in worldwide populations. Because of its historical background, Brazilians are very suitable for population genetic studies. Therefore, 104 bone marrow donors from Brazil were evaluated for HLA-E exons 14. Seven variation sites were found, including two known single nucleotide polymorphisms (SNPs) at positions +424 and +756 and five new SNPs at positions +170 (intron 1), +1294 (intron 3), +1625, +1645 and +1857 (exon 4). Haplotyping analysis did show eight haplotypes, three of them known as E*01:01:01, E*01:03:01 and E*01:03:02:01 and five HLA-E new alleles that carry the new variation sites. The HLA-E*01:01:01 allele was the predominant haplotype (62.50%), followed by E*01:03:02:01 (24.52%). Selective neutrality tests have disclosed an interesting pattern of selective pressures in which balancing selection is probably shaping allele frequency distributions at an SNP at exon 3 (codon 107), sequence diversity at exon 4 and the non-coding regions is facing significant purifying pressure. Even in an admixed population such as the Brazilian one, the HLA-E locus is very conserved, presenting few polymorphic SNPs in the coding region.
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This study describes a simple method for long-term establishment of human ovarian tumor lines and prediction of T-cell epitopes that could be potentially useful in the generation of tumor-specific cytotoxic T lymphocytes (CTLs), Nine ovarian tumor lines (INT.Ov) were generated from solid primary or metastatic tumors as well as from ascitic fluid, Notably all lines expressed HLA class I, intercellular adhesion molecule-1 (ICAM-1), polymorphic epithelial mucin (PEM) and cytokeratin (CK), but not HLA class II, B7.1 (CD80) or BAGE, While of the 9 lines tested 4 (INT.Ov1, 2, 5 and 6) expressed the folate receptor (FR-alpha) and 6 (INT.Ov1, 2, 5, 6, 7 and 9) expressed the epidermal growth factor receptor (EGFR); MAGE-1 and p185(HER-2/neu) were only found in 2 lines (INT.Ov1 and 2) and GAGE-1 expression in 1 line (INT.Ov2). The identification of class I MHC ligands and T-cell epitopes within protein antigens was achieved by applying several theoretical methods including: 1) similarity or homology searches to MHCPEP; 2) BIMAS and 3) artificial neural network-based predictions of proteins MACE, GAGE, EGFR, p185(HER-2/neu) and FR-alpha expressed in INT.Ov lines, Because of the high frequency of expression of some of these proteins in ovarian cancer and the ability to determine HLA binding peptides efficiently, it is expected that after appropriate screening, a large cohort of ovarian cancer patients may become candidates to receive peptide based vaccines. (C) 1997 Wiley-Liss, Inc.
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Individual differences in drug efficacy or toxicity can be influenced by genetic factors. We investigated whether polymorphisms of pharmacogenes that interfere with metabolism of drugs used in conditioning regimen and graft-versus-host disease (GvHD) prophylaxis could be associated with outcomes after HLA-identical hematopoietic stem cell transplantation (HSCT). Pharmacogenes and their polymorphisms were studied in 107 donors and patients with leukemia receiving HSCT. Candidate genes were: P450 cytochrome family (CYP2B6), glutathione-S-transferase family (GST), multidrug-resistance gene, methylenetetrahydrofolate reductase (MTHFR) and vitamin D receptor (VDR). The end points studied were oral mucositis (OM), hemorrhagic cystitis (HC), toxicity and venoocclusive disease of the liver (VOD), GvHD, transplantation-related mortality (TRM) and survival. Multivariate analyses, using death as a competing event, were performed adjusting for clinical factors. Among other clinical and genetic factors, polymorphisms of CYP2B6 genes that interfere with cyclophosphamide metabolism were associated with OM (recipient CYP2B6*4; P=0.0067), HC (recipient CYP2B6*2; P=0.03) and VOD (donor CYP2B6*6; P=0.03). Recipient MTHFR polymorphisms (C677T) were associated with acute GvHD (P=0.03), and recipient VDR TaqI with TRM and overall survival (P=0.006 and P=0.04, respectively). Genetic factors that interfere with drug metabolisms are associated with treatment-related toxicities, GvHD and survival after HLA-identical HSCT in patients with leukemia and should be investigated prospectively.
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The HLA-G gene is predominantly expressed at the maternal-fetal interface. It has been associated with maternal-fetal tolerance and in the inhibition of cytotoxic T lymphocyte and natural killer cytolytic functions. At least two variations in the 3` untranslated region (UTR) of HLA-G locus are associated with HLA-G expression levels, the 14-bp deletion/insertion polymorphism and the +3142 single-nucleotide polymorphism (SNP). However, this region has not been completely characterized yet. The variability of the 3`UTR of HLA-G gene and its haplotype structure were characterized in 155 individuals from Brazil, as well as HLA-G alleles associated with each of the 3`UTR haplotype. The following eight variation sites were detected: the 14-bp polymorphism and SNPs at the positions +3003T/C, +3010C/G, +3027A/C, +3035C/T, +3142G/C, +3187A/G and +3196C/G. Similarly, 11 different 3`UTR haplotypes were identified and several HLA-G alleles presented only one 3`UTR haplotype. In addition, a high linkage disequilibrium among the variation sites was detected, especially among the 14-bp insertion and the alleles +3142G and +3187A, all previously associated with low mRNA availability, demonstrating that their effects are not independent. The detailed analyses of 3`UTR of the HLA-G locus may shed some light into mechanisms underlying the regulation of HLA-G expression. Genes and Immunity (2010) 11, 134-141; doi: 10.1038/gene.2009.74; published online 1 October 2009
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Haemochromatosis associated with mutations in the HFE gene is the most common inherited disorder in Caucasian populations. Early diagnosis and treatment allows for normal life expectancy whereas there is considerable morbidity and early mortality in those patients diagnosed late or untreated. Unfortunately, the development of symptoms and signs in haemochromatosis is usually associated with significant iron overload. For this reason, many clinicians and geneticists have advocated population screening. The recent identification of the HFE gene and the availability of a simple DNA-based diagnostic test have led to international debate as to the most cost-effective means of population screening for HFE-associated haemochromatosis. The present paper summarizes the evidence in favour of population screening and analyses the relative advantages of genotypic (DNA test) versus phenotypic (transferrin saturation) testing.