Les travaux de cette thèse portent sur :<br />− la proposition d'algorithmes de simulation distribuée conservative de modèles DEVS / G-DEVS,<br />− la définition et la réalisation d'un environnement de modélisation & simulation (M&S) G-DEVS com-patible HLA implémentant les algorithmes proposés,<br />− l'application de l'environnement à la M&S de Workflow.<br />Dans un premier temps, nous avons introduit un composant coordinateur racine G-DEVS distribué, incluant un algorithme de communication avec le RTI HLA basé sur le mécanisme de synchronisation conservative et utilisant un Lookahead positif. Nous avons ensuite proposé deux algorithmes originaux pour le calcul d'un Loo-kahead relatif à l'état courant d'un modèle G-DEVS. Ces algorithmes, basés sur l'analyse du domaine de varia-tion de la fonction « durée de vie » du modèle, augmentent les performances de la simulation distribuée comme l'illustrent les expériences menées.<br />Basé sur ces approches, nous avons développé un environnement de M&S distribué G-DEVS / HLA. Cet environnement a été intégré à une application de Workflow. Les possibilités offertes par l'environnement ont été illustrées par l'étude de cas réels d'entreprises.

La chaîne invariante forme un complexe nonamérique avec les molécules classiques du CMH de classe II. HLA-DM et HLA-DO, des molécules non-classiques de classe II, sont aussi impliquées dans la présentation des peptides antigéniques aux lymphocytes T. Ces molécules chaperones de la présentation antigénique modulent la capacité d’une cellule à présenter des antigènes par les moloécules classiques du CMH de classe II. La régulation transcriptionnelle des molécules chaperones, tout comme celle des autres molécules du CMH de classe II, est assurée par le transactivateur CIITA. La molécule HLA-DR peut être régulée négativement de manière post-traductionnelle par ubiquitination grâce à l’enzyme E3 ubiquitine ligase MARCH1. Celle-ci est induite par l’interleukine-10 dans les monocytes. L’objectif de ce projet était de déterminer si l’ubiquitination par MARCH1 peut aussi réguler l’expression des molécules chaperones de la présentation antigénique. Les expériences furent réalisées dans le contexte de co-transfections en cellules HEK293T. L’expression des molécules fut évaluée par immunomarquages et cytométrie de flux. Il a été montré que l’isoforme p33 de la chaîne invariante est régulé négativement en présence de MARCH1 à partir de la surface cellulaire, causant ainsi sa dégradation. Tel que démontré par l’utilisation d’un mutant dépourvu de queue cytoplasmique, cette dernière région n’est pas indispensable à ce phénomène. Une hypothèse est qu’une molécule non-identifiée, associée à Ii, serait ubiquitinée par MARCH1, l’entraînant dans sa régulation négative. Il fut déterminer que cette molécule n’était pas CXCR2, un récepteur pouvant être impliqué, avec la chaîne invariante et CD44, en tant que récepteur de MIF (Macrophage Inhibitory Factor). Il fut aussi montré que HLA-DO peut être ciblé par MARCH1 mais ceci ne semble pas être un phénomène dominant; l’expression des complexes DO/DM n’étant pas affectée bien qu’ils entrent en interaction avec MARCH1. L’expression de HLA-DM n’est pas affectée par MARCH1. Il n’a toutefois pas été déterminé hors de tout doute si MARCH1 peut modifier DM; des résultats obtenus avec une queue cytoplasmique de DM possédant une lysine laissant suggérer qu’il est possible que MARCH1 interagisse avec DM. Dans l’ensemble, les travaux démontrent que l’ubiquitination par MARCH1 joue un rôle dans la régulation post-transcriptionnelle de la chaîne invariante p33 mais pas HLA-DO et HLA-DM. / The invariant chain, which form a nonameric complex with the classical MHC class II molecules. HLA-DM and HLA-DO (non-classical class II molecules) are involved in the presentation of antigens to T lymphocytes. The chaperons molecules of the antigenic presentation can modulate the capacity of the cells to present antigens. The transcriptional regulation of the chaperons and all of the other molecules linked to the MHC is assured by the CIITA transactivator. Little is know of the post-transcriptional mechanisms, other than the fact that HLA-DR molecule can be down-regulated by ubiquitination due to E3 ubiquitin ligase MARCH1. MARCH1 is induce by interleukin-10 in monocytes. The goal of this project is to figure out if ubiquitination by MARCH1 can also regulate the expression of the antigenic presentation chaperons. The experiences were performed in the context of co-transfections in HEK293T cells and the expression of the diverses molecules was evaluated by cell stainings and FACS analysis. The p33 isoform of the invariant chain was found to be down-regulated and degraded in the presence of MARCH1. The invariant chain cytoplasmic tail is not completely essential to this phenomenon; a non-identified molecule, associated with Ii, is probably ubiquitinated by MARCH1 and is then down-regulated, together with Ii. It was shown tha CXCR2, a reeptor involved with the invariant chain and CD44 in the reception of the MIF signal, is not that molecule. HLA-DO can ben targetd by MARCH1 but this does not seem to be a general phenomenon; the expression of the DO/DM complexes remaning unaffected even with the interaction of those complexes with MARCH1. Therefore, a certain protection seem to be provided by HLA-DM to HLA-DO. The expression of HLA-DM itself is not affected by the presence of MARCH1. However, it was not cleary demonstrated if MARCH1 can modify DM. Some results obtained with a cytoplasmic tail of DM comprising an additional lysine suggest that there is a possibility that MARCH1 interact with DM. Generally, the work presented here show that ubiquitination by MARCH1 is involved in post-transcriptionnal regulation of the p33 isoform of the invariant chain but not in the regulation of HLA-DO and HLA-DM.

The MHC class I allele, HLA-B27, is strongly associated with a group of inflammatory arthritic conditions collectively known as spondyloarthropathies (SpA). Ankylosing spondylitis (AS) shows the strongest association with 90-95 % of patients being HLA-B27 positive. The relationship between HLA-B27 and SpA has been known for over 30 years, however despite ongoing research, the reason for this association has not yet been elucidated. In more recent years, research has focused on intrinsic properties of the HLA-B27 allele, in particular its propensity to misfold, forming homodimers. It has been proposed that these homodimers could be associated with the disease process through the activation of an ER stress response known as the unfolded protein response (UPR), or through aberrant recognition at the cell surface. We have investigated whether the expression of HLA-B27 is associated with the activation of the UPR. We have studied the expression of BiP, and the cleavage of XBP1 and ATF6 using stable and transiently expressing cell lines. We have also investigated the formation of non-B27 homodimers using a human cell line stably expressing HLA-B8, and finally we have studied the expression of homodimers in exosomes, small immunomodulatory vesicles released from numerous cell types. The results presented here lead us to conclude that in vitro studies of the UPR are complicated, prone to a number of technical issues, and may therefore not be appropriate for gaining information that would be of significant use when comparing to the real disease scenario. Our data suggest that non-B27 dimers may be strongly influenced by both the overexpression of MHC class I heavy chains and also the redox environment within the cell. We have isolated a novel fully folded, beta-2m-associated, MHC class I homodimer in exosomes and have detected a novel HLA-A and HLA-B mixed heavy chain dimer. Our results suggest that these dimers form through interactions between the cysteine residues in the cytoplasmic tail and that these dimers form in exosomes because they contain lower levels of the important antioxidant glutathione when compared to whole cells. Together, these results define a new MHC class I structure present on exosomes at significant levels, which could potentially influence immune recognition by both antigen-specific T cell receptors and NK family receptors. The data also poses questions about whether these novel structures, when they involve HLA-B27, could influence the pathogenesis of spondyloarthropathies.

Les molécules classiques du CMH de classe II présentent des peptides antigéniques aux lymphocytes T CD4+. Cette présentation est régulée par deux molécules non classiques : HLA-DM catalyse la relâche de CLIP et le chargement de peptides et HLA-DO module l’activité de DM. Une expression insuffisante en cellules d’insectes empêche les expériences de cristallisation de DO, probablement en raison de sa conformation, rendant DO instable et inapte à sortir du réticulum endoplasmique (RE). DM corrige la conformation de DO et permet sa sortie du RE. Aussi, par ses ponts disulfures uniques, DM adopte une conformation stable et peut sortir du RE sans lier d’autre molécule. Nous avons tenté de corriger la conformation de DO en introduisant des cystéines pour établir des ponts homologues à ceux de DM. La conformation de DO ne fut pas corrigée. Par ailleurs, nous avons augmenté l’expression de DO en introduisant une séquence partielle de Kozak. Nous avons aussi étudié l’effet de DM sur l’expression de DO. DM a favorisé l’expression de DO, probablement en diminuant sa dégradation. Chaque chaîne du dimère DMαβ est impliquée dans l’oxydation de sa chaîne partenaire. La conformation non-optimale de DO pourrait traduire une incapacité des chaînes α ou β à favoriser l’oxydation de sa partenaire; DM corrigerait ce problème. Notre analyse d’immunobuvardage de type Western a toutefois démontré que DM ne modifie pas l’état d’oxydation de DOα et DOβ. Finalement, nous avons étudié l’interaction DO-DM. L’acide aminé DOαE41 est impliqué dans cette liaison. Certains des acides aminés entre α80 et α84 pourraient être impliqués. Nous avons muté des acides aminés de cette région de DOα. Les résidus testés ne semblent pas impliqués dans la liaison DO-DM. L’obtention de la structure tridimensionnelle de DO et la caractérisation de son état oxydatif et de sa liaison à DM permettront de mieux comprendre son rôle. / Classical MHC class II molecules present antigenic peptides to CD4+ T cells. This presentation is regulated by two non-classical molecules: HLA-DM catalyzes CLIP release and peptide loading and HLA-DO mediates the DM activity. An insufficient expression in insect cells did not allow DO crystal production experiments, probably because of its conformation, rendering DO unstable and unable to leave the endoplasmic reticulum (ER). DM corrects the conformation of DO and allows its egress from the ER. Also, because of its unique disulfide bonds, DM has a stable conformation and can egress from the ER without binding another molecule. We tried to correct the conformation of DO by introducing cysteines to create disulfide bonds homologous to those of DM. However, its conformation was not corrected. Also, we increased DO expression by inserting a partial Kozak sequence. We also studied the effect of DM on DO expression. DM favoured DO expression, probably by reducing its degradation. Each chain of the DMαβ dimer plays a role in the oxidation of its partner chain. The non-optimal conformation of DO might result from an incapacity of its α and β chains to direct each other’s oxidation; DM would correct this problem. Our Western blot analysis showed, however, that DM does not modify the oxidation state of DOα and DOβ. Finally, we studied the DO-DM interaction. The DOαE41 amino acid is involved in this interaction, as some of the α80 to α84 might be. We mutated amino acids in this region of DO. Tested amino acids did not seem involved in DO-DM binding. The tridimensional structure of DO and the characterization of its oxidative state and its DM binding will allow a better understanding of its function.

Chez la femme, la majorité des cas d’infection au VIH sont acquis lors de relations hétérosexuelles. Cependant, très peu d’informations sont disponibles concernant l’immunité locale naturelle du tractus génital féminin, les facteurs influençant la susceptibilité à l’infection au VIH dans ce compartiment, ainsi que la réponse immunitaire de la muqueuse enclenchée après l’infection. Le but de notre projet est donc d’étudier certains facteurs pouvant être impliqués dans la susceptibilité à l’infection au VIH, afin de mieux comprendre l’immunité du tractus génital féminin. Nous avons, dans un premier temps, analysé le rôle du polymorphisme des gènes HLA-G et HLA-E sur la susceptibilité au VIH dans une population de femmes zimbabwéennes. La présence de l’allèle HLA-G*0105N, en combinaison avec le génotype HLA-EG/HLA-EG, était associée avec une diminution du risque d’infection. Puis, dans une étude cas-contrôle de travailleuses du sexe (TS) du Bénin, nous avons mesuré l’expression de HLA-G soluble au niveau du plasma. Nous avons observé une différence significative dans l’expression de HLA-G soluble, celle-ci étant plus faible dans le groupe des TS VIH positives comparé aux groupes de TS VIH négatives et de femmes VIH négatives de la population générale. Nous avons aussi analysé l’expression de cytokines et chimiokines dans le sérum et le tractus génital des participantes de l’étude du Bénin. Nous avons constaté que chez les TS VIH positives il y avait une expression plus élevée des chimiokines MPC-3, IP-10 et MIG dans le tractus génital et le sérum comparativement aux deux autres groupes. Les patrons d’expression des cytokines variaient selon les compartiments : le niveau de TNF-α et IFN-γ était plus élevé dans le tractus génital des TS VIH positives, alors que le niveau d’IL-2, d’IL-10 et de TNF-α était plus faible dans le sang des TS VIH positives, comparativement aux deux autres groupes. Ainsi, au niveau du tractus génital des femmes VIH positives, il semble y avoir une activation chronique du système immunitaire dans le but de favoriser la dissémination/perpétuation du virus. Les patrons d’expression différents entre le milieu systémique et génital nous montrent que l’immunité présente dans un compartiment n’est pas nécessairement le reflet de l’autre. Nous avons aussi observé une augmentation significative des niveaux d’IL-4, de MIP-1α, de MIP-1β et de MCP-1 dans le sérum des TS VIH négatives. Ces personnes, hautement exposées mais non infectées, semblent démontrer une plus grande capacité à enclencher une réponse immunitaire précoce pour empêcher la dissémination du virus. Notre étude a donc permis d’acquérir de nouvelles connaissances sur l’immunité du tractus génital féminin en relation avec l’infection au VIH. / Initial exposure to HIV during heterosexual transmission occurs in the female genital tract. However, little is known about the local immunity, the factors influencing the susceptibility to HIV infection and the immune response in the female genital tract against HIV infection. The aim of this study is to analyse some factors that could be implicated in the susceptibility to HIV infection and to analyse, in part, the immunity present in the female genital tract. We investigated the role of HLA-G and HLA-E in the susceptibility to HIV infection in a cohort of Zimbabwean women. We found that the presence of HLA-G*0105N allele in combination with the genotype HLA-EG/HLA-EG was associated with a decrease in the risk of HIV infection. We also measured the expression of soluble HLA-G in a study of commercial sex workers (CSW) in Benin. Levels of soluble HLA-G were lower in the HIV-1-infected CSWs compared to those observed in both the HIV-1-uninfected CSWs and the HIV-1-uninfected women from the general population at low risk of infection. We also analysed the chemokine and cytokine expression patterns in the serum and female genital tract of the three groups of women. HIV-1-infected CSWs had significantly higher blood and genital levels of the chemokines IP-10, MCP-3 and MIG compared with those in both the HIV-1-uninfected CSW and non-CSW groups. HIV-1-infected CSWs had significantly higher genital mucosal levels of the cytokines TNF-α and IFN-γ compared with those in both the HIV-uninfected CSW and non-CSW groups. In contrast, the serum levels of the cytokines IL-2, IL-10 and TNF-α were lower in HIV-1-infected CSWs compared with those in the other groups. This suggests the presence of a constant immune cells recruitment and immune activation in the female genital tract in order to favour perpetuation and dissemination of the virus. Our results also demonstrate the important difference between the systemic and the mucosal immunity. We also observed a significant increase in the levels of IL-4, MIP-1α, MIP-1β and MCP-1 in the serum of the HIV-1-uninfected CSWs. It seems that these highly-exposed and yet uninfected women can have a better capacity to mount an early immune response against HIV. This study gives us new insights of the mucosal immunology of HIV infection.

Kidney transplantation is the treatment of choice for patients with end stage renal failure and is associated with prolonged survival of patients and better quality of life than long-term dialysis. Simultaneously, however, transplantation carries the risk of immunological complications leading to graft rejection. A serious problem in patients after organ transplantation is the development of humoral rejection, which is most often associated with the presence of antibodies specific to HLA antigens, particularly against mismatched HLA antigens of the organ donor. In certain cases antibodies may be specific to antigens expressed on endothelial cells, not on lymphocytes, like MICA, MICB, ICAM, and up till now unidentified tissue-specific antigens. Humoral rejection has significantly worse prognosis for the transplanted kidney than cellular rejection, and therefore its timely diagnosis is of great importance for the subsequent choice of appropriate therapy. The diagnosis of humoral rejection is based on the simultaneous detection of C4d deposits in the peritubular capillaries of the transplanted kidney and the finding of antibodies specific to the mismatched antigens of the donor (donor specific antibodies, DSA). The aim of our retrospective study was to contribute to improvement of the diagnosis of acute and...

Introduction: At our post-genomic era the studies of epigenetic regulation constitutes one of the tools for understanding the function of genes. Epigenetic regulation can directly control the temporal and spatial gene activity or silencing. The molecular basis of these regulations are DNA bases modifications, chromatin remodeling and RNA interference. At the same time, these mechanisms have a special way of transferring genetic information to subsequent generations called epigenetic inheritance. It has been proven epigenetic deregulation of certain genes as cause for many disease. For this reason, the study of epigenome HLA genes seems particularly important because these genes play a fundamental role in regulating the immune system. Aims: The aim of this work is to create a description of epigenetic modifications within families. It is an analysis of histone modifications and DNA methylation in the promoter region of the gene HLA DQA1. The aim was also to compare the differences in epigenetic modifications between alleles and compared the differences in these modifications between generations. The results will be compared with the analysis of the level of expression of the gene HLA DQA1. Methods: From collected peripheral blood of donors were isolated DNA, RNA, and leukocytes. DNA was used for...

O diabetes mellitus tipo 1A (DM1) é uma doença crônica caracterizada pela destruição imunológica das células ? do pâncreas e pela incapacidade de seu portador produzir insulina. Nas últimas décadas foram descritos vários aspectos sobre a fisiopatologia do DM1 e identificado um aumento de sua incidência mundial. Entretanto, na literatura há lacunas a serem respondidas envolvendo a etiologia e a imunopatologia desta doença. No presente trabalho, foi analisado o impacto de duas moléculas endógenas imunoregulatórias, Antígeno Leucocitário Humano-G (HLA-G) e Galectina-1 (GAL-1), no DM1 humano e experimental. Para tanto, as formas recombinantes de HLA-G (-G5 e -G6) e seus respectivos anticorpos foram produzidos e/ou bioquimicamente caracterizados. A partir de amostras de pacientes diagnosticados com DM1 ou de indivíduos controle foi feita uma análise comparativa envolvendo o perfil de expressão do HLA-G e da GAL-1 e a identificação de microRNAs (miRNAs) associados a estas duas moléculas. Camundongos Lgals-/- ou não para o gene da GAL-1 foram tratados com estreptozotocina (STZ) para indução do DM1 experimental. As duas formas recombinantes do HLA-G foram produzidas, mas apenas o HLA-G6 foi caracterizado como uma solução polidispersa contendo um componente majoritário (99,2%) com massa molecular de 23.603,766 Da, raio hidrodinâmico de 6,0 ± 2,0 nm e imunoreatividade para diferentes anticorpos anti-HLA-G comerciais ou produzidos no laboratório. Os níveis transcricional e proteico do HLA-G e da GAL-1 não foram diferentes entre os grupos de indivíduos estudados. A análise comparativa de miRNAs mostrou que a elevada indução do miRNA modulador negativo da expressão do HLA-G (hsa-miR-16-5p) nos controles em relação aos pacientes foi a única associação robusta com a patogenia do DM1. Curiosamente, os animais selvagens apresentam maior suscetilibilidade à indução de DM1 por STZ, uma vez que os indicadores desta doença como o grau de insulite, a taxa de migração de linfócitos T CD4 e T CD8 para os linfonodos pancreáticos, o nível de redução de insulina no pâncreas e a taxa glicêmica estavam aumentados nesses animais em relação aos nocautes para GAL-1. Finalmente, este conjunto de resultados sugere que possa ocorrer uma regulação positiva da expressão de transcritos do HLA-G em pacientes com DM1 e que a presença de GAL-1 endógena pode favorecer o DM1 experimental. Estes dados abrem novas perspectivas para o melhor entendimento da imunopatologia do DM-1 / Diabetes Mellitus type 1A (DM1) is a chronic disease characterized by the immune destruction of pancreatic beta cells and by the consequent inability of its bearer to produce insulin. For the last decades, several aspects of the pathophysiology of DM1 were described and an increase on its worldwide incidence has been identified.Nevertheless, there are gaps in the literature related to aspects of its etiology and immunopathology to be filled.In the present work, the impact of two endogenous immunoregulatory molecules, Human Leukocyte Antigen-G (HLA-G) and Galectin-1 (GAL-1), was analyzed on human and experimental DM1.To do so, the recombinant forms of HLA-G (-G5 and - G6) and its respective antibodies were produced and/or biochemically characterized. A comparative analysis involving the expression profile of HLA-G and GAL-1 and the identification of microRNAs (miRNAs) associated with these two molecules was made from samples of patients diagnosed with DM1, or control subjects. Mice deficient or not for the GAL-1 gene were treated with streptozotocin (STZ) for the induction of experimental DM1.Both recombinant forms of HLA-G were produced, but only HLA-G6 was characterized as a polydisperse solution containing a major component (99.2%), with molecular mass of 23,603,766 Da, hydrodynamic radius of 6.0 ± 2.0 nm, and immunoreactivity for different commercial or lab produced anti-HLA-G antibodies HLA-G and GAL-1. The transcriptional and protein levels were not different between the groups of subjects studied. High induction of the negative modulator miRNA expression of HLA-G (hsa-miR-16-5p) in the controls compared to the patients was the only robust association found with the pathogenesis of DM1.Interestingly, wild type animals presented more susceptibility to the induction of DM1 by STZ, once the indicators of this disease such as the degree of insulin, the migration rate of CD4 T and CD8 T lymphocytes to pancreatic lymph nodes, the level of insulin reduction in the pancreas and the glycemic rate were increased in wild type mice (Lgals-1+/+) when compared to GAL-1-knock out mice (Lgals-1-/-). Finally, this set of results suggests that a positive regulation of the expression of HLA-G transcripts may occur in patients with DM1 and that the presence of endogenous GAL-1 may favor the experimental DM1. These data open new perspectives for a better understanding of the immunopathology of DM-1

A doença hepática crônica causada pelo vírus da hepatite C (HCV) tornou-se, nos últimos anos, uma das principais comorbidades dos pacientes portadores do vírus da imunodeficiência humana (HIV) nos países desenvolvidos. Os pacientes coinfectados com HIV/HCV apresentam uma progressão mais rápida para a cirrose e as suas complicações que os pacientes monoinfectados com HCV. Embora os mecanismos responsáveis por esta evolução não estejam totalmente esclarecidos, a expressão da molécula de HLA-G, um HLA de classe Ib não clássico, que tem propriedades bem reconhecidas na regulação negativa da resposta imune, pode estar relacionada à progressão da doença hepática. Os objetivos deste trabalho foram analisar o perfil de expressão de HLA-G em tecido hepático de pacientes coinfectados HIV/HCV e identificar possíveis variáveis do hospedeiro, do HCV e do HIV que possam estar relacionadas com a expressão de HLA-G na biópsia hepática. Para isso, 57 amostras de biópsia hepática de pacientes coinfectados com HIV/HCV, nas quais a imuno-histoquímica para HLA-G foi realizada, foram analisadas retrospectivamente quanto à expressão desta molécula no tecido hepático. Avaliaram-se também outras características histopatológicas da biópsia como grau de fibrose, atividade inflamatória, deposição de ferro e gordura. Determinou-se o polimorfismo de inserção ou deleção de 14 pares de bases da região 3` não traduzida do exon 8 do gene do HLA-G, que está relacionada com a produção de RNA-mensageiro, em 43 destes pacientes, além do polimorfismo de IL-28B, relacionado com a resposta ao tratamento do HCV, em 44 deles. Características bioquímicas e virológicas, tanto do HIV quanto do HCV também foram avaliadas. O genótipo 1 do HCV foi o mais prevalente (87,75%), especialmente o subgenótipo 1a (60%). A expressão do HLA-G foi observada em 38 (66,7%) amostras de fígado, e foi mais frequente em estágios moderados e severos de fibrose do que em estágios mais leves (94,1% x 55%, P < 0,01). Não houve relação entre a expressão do HLA-G e os outros parâmetros estudados. Embora a progressão para a cirrose no contexto da coinfecção por HIV/ HCV seja um processo complexo, modulado por muitos factores, a associação da intensidade de fibrose com a expressão do HLA-G pode indicar que a expressão desta proteína desempenha um importante papel nos mecanismos que contribuem para a progressão da doença, por meio da regulação negativa da resposta imune contra o HCV na coinfecção pelo HIV. / Chronic liver disease induced by hepatitis C virus (HCV) infection has recently become one of the most common comorbidities in patients who are infected with the human immunodeficiency virus (HIV) in developed countries. HIV/HCV coinfected patients show faster progression to cirrhosis and its complications than the HCV monoinfected patients. Even though the responsible mechanisms for this evolution have not been entirely clarified yet, the expression of the HLA-G molecule, a HLA from the non-classic Ib class, with well-known properties of negatively regulating the immune response, may be related to the liver disease progression. The aims of the present work were to analyze the HLA-G expression profile in the liver micro ambience of HIV/HCV coinfected patients and to identify possible host factors, HIV or HCV, that may be related to the HLA-G expression on the liver biopsy. For this purpose, 57 liver biopsies of HIV/HCV coinfect patients, in which immunohistochemistry for HLA-G had been performed, were retrospectively analyzed according the HLA-G expression on the hepatic tissue. Other histopathological features in the liver biopsies, such as fibrosis degree, inflammatory activity, iron deposition and fat were also evaluated. The polymorphism of insertion or deletion in 14-base pairs of the 3`non-translated region of exon 8 of the HLA-G gene, which is related to the production of HLA-G messenger RNA, was evaluated in 43 of the patients. Also, the polymorphism of IL-28B, related to the response to HCV treatment, was evaluated in 44 of them. Biochemical and virological features of HIV and HCV were also evaluated. The HCV genotype 1 was the most prevalent (87.75%), especially the subgenotype 1a (60%). The expression of HLA-G was observed in 38 (66.7%) samples of the liver biopsies, and it was most frequent in moderate and severe stages of fibrosis than in the mild stages (94.1% x 55%, P < 0.01). There was no established relationship between HLA-G and other parameters studied. Although the progression to cirrhosis in the context of HIV/HCV coinfection is a complex process modulated by many factors, the association of HLA-G expression with the intensity of the liver fibrosis may indicate the protein expression play an important role in the mechanisms that contribute to the progression of the disease, through the negative regulation of the immune response against HCV setting of a coinfection with HIV.

A elevada e crescente prevalência do carcinoma basocelular (CBC) na população caucasiana e o seu marcante predomínio entre os cânceres cutâneos não-melanoma despertam interesse para a elucidação dos mecanismos envolvidos no seu desenvolvimento. Os vários subtipos da neoplasia possuem características de interesse para um modelo de estudo, a fim de identificar os fatores determinantes dos diferentes padrões de crescimento. Objetivo: Neste estudo buscamos analisar, por meio da expressão de citocinas, linfócitos, VEGF e HLA-G, os possíveis mecanismos imunomoduladores envolvidos nos diferentes padrões de crescimento, subtipos e localizações topográficas do CBC. Métodos: Em 26 amostras de fragmentos dos subtipos nodular e superficial de CBC primários, foram analisadas a expressão de CD3, CD4, CD25, FOXP3, HLA-G e VEGF, por meio imunoistoquímica (IHQ), e de IL-4, IL-6, IL-8, IL-10, IL-17, IL-23, FOXP-3 e IFN-gama, por meio da reação em cadeia da polimerase em tempo real quantitativa (qPCR). Resultados: Na amostra (n=26), houve discreto predomínio de homens (54%), com idade variando entre 35 a 89 anos e média de 72,96 anos; 84,62% dos CBC eram localizados em área fotoexposta, 53,85% não-cefálicos (14/26) e 46,15% cefálicos (12/26). CBC nodulares apresentaram um infiltrado inflamatório mais evidente e concentrado ao redor dos blocos neoplásicos; CBC superficiais apresentaram um infiltrado inflamatório difuso por toda a derme, e discretamente mais intenso nas áreas adjacentes aos blocos tumorais. A expressão de todos os marcadores foi mais evidente no sítio perineoplásico (PN) comparado ao interior, das células neoplásicas (Cneo). Distintamente de outros marcadores, notou-se acentuada frequência da expressão de CD25+ e HLA-G nas Cneo. Nas Cneo dos CBCn, evidenciou-se elevada frequência de células marcadas em intensidade moderada para HLA-G (p=0,04) e em intensidade leve para FOXP3 (p = 0,037), quando comparados aos CBCs. A expressão de CD4+ no infiltrado PN foi mais frequente nos tumores não-cefálicos (p=0,02) comparados aos cefálicos. A expressão de citocinas IL-6 IL-8, IL-17 foi maior nos dois subtipos de CBC, nodular e superficial, comparada à da pele normal. CBC cefálicos apresentaram maior expressão de IL-4 (p=0,02), enquanto aqueles de localização não-cefálica expressaram mais IL-8 (p=0,002). Conclusão: A composição e a localização do infiltrado inflamatório corroboram a resposta imunológica mediada por células T CD3+ e CD4+ no CBC. A participação de linfócitos CD25+, FOXP3+ e do HLA-G caracteriza uma ação imunomoduladora, e a presença das interleucinas IL-8 e do perfil Th17, IL-6 e IL-17, podem favorecer a neovascularização e a supressão de células efetoras no microambiente do CBC propiciando o seu desenvolvimento e escape tumoral. / Introduction: The high and increasing prevalence of basal cell carcinoma (BCC) in the Caucasian population, and its striking predominance between non-melanoma skin cancers arouse interest for the elucidation of the mechanisms involved in its development. Its various subtypes have characteristics of interest for a study model in order to identify the determinants of different patterns of growth. Objective: This study aims to analyze the possible immunomodulatory mechanisms involved in the different growth patterns, and topographic locations subtypes of BCC through the expression of cytokines, lymphocytes, VEGF and HLA-G. Methods: In 26 fragments samples of primary BCC, subtypes nodular and superficial, we analyzed the expression of CD3, CD4, CD25, FOXP3, HLA-G and VEGF by immunohistochemistry (IHC) technique, and of cytokines IL-4, IL-6, IL-8, IL-10, IL-17, IL-23, FOXP-3 and IFN- by quantitative real time polymerase chain reaction (qPCR). Results: The sample (n = 26) had a slight predominance of men (54%), aged between 35-89 years, mean age 72.96 years; 84.62% of the BCC were located in sun-exposed area, 53.85% (14/26) non-cephalic and 46.15% (12/26) cephalic. Nodular BCC showed a more evident and concentrated inflammatory infiltrate around the tumor blocks; while superficial BCC showed a diffuse inflammatory infiltrate throughout the dermis, and slightly more intense in tumor blocks adjacent areas. The expression of all markers was evident at the perineoplastic (PN) sites compared to neoplastic cells (Cneo). Differently from other markers, we noticed strong frequency expression of CD25+ and HLA-G within the Cneo. In Cneo of BCCn, it became apparent high frequency of moderate HLA-G marked cells (p = 0.04) and at low intensity for FOXP3 (p = 0.037) when compared to BCCs. The expression in CD4+ infiltrate was more frequent in PN non-cephalic tumors (p = 0.02) compared with cephalic. The expression of IL-6 IL-8, IL-17 was higher in both subtypes of BCC, nodular and superficial, compared to normal skin. Cephalic BCC showed higher expression of IL-4 (p=0,02) while those from non-cephalic location expressed more IL-8 (p=0,002). Conclusion: The composition and location of the inflammatory infiltrate corroborate the immune response mediated by CD3+ and CD4+ T cells on the BCC. The involvement of HLA-G, CD25+ and FOXP3 lymphocytes features an immunomodulary action, and the presence of interleukin IL-8 and Th17 profile (IL-6 and IL-17) may promote neovascularization and suppression of effector cells in the BCC microenvironment providing its development and tumor escape.