Les Facteurs de transcription du groupe PEA3 (Pea3, Erm et Er81) font partie de la famille d’oncogènes ETS. Leur expression est souvent observée lors de la mise en place des organes par morphogenèse de branchement tels que les poumons ou encore la glande mammaire. De plus une expression aberrante de ces facteurs de transcription est corrélée au caractère cancéreux de nombreux tissus tels que le côlon, les poumons ou encore le sein. Ainsi, l’expression d’Erm dans les tumeurs du sein est associée à un mauvais pronostic pour les patientes et celle de Pea3 constitue un marqueur de l’agressivité tumorale. Enfin, en qualité de facteur de transcription Pea3 module l’expression de gènes spécifiques alors appelés gènes cibles. Même si certains de ces gènes sont déjà bien caractérisés beaucoup de choses restent à faire pour comprendre les mécanismes moléculaires régulés par Pea3. Dans ce contexte lors de ma thèse je me suis intéressé à l’étude du rôle du facteur de transcription Pea3 dans les processus de morphogenèse et de tumorigenèse mammaires selon deux approches complémentaires : 1- l’étude des propriétés morphogénétiques modulées par Pea3 lors des étapes de morphogenèse et de tumorigenèse mammaires, 2- la recherche et la caractérisation de gènes régulés par Pea3 dans ce même contexte, par une analyse transcriptomique à grande échelle en utilisant des puces à ADN. Ces deux points sont développés grâce à l’utilisation de modèles cellulaires dans lesquelles nous modulons l’expression de Pea3. Les cellules épithéliales mammaires TAC 2.1 modèle de morphogenèse mammaire dans lesquelles nous surexprimons Pea3 et les cellules mammaires transformées MMT, modèle de tumorigenèse mammaire dans lesquelles nous inhibons l’expression du facteur de transcription Pea3. Au cours de ma thèse nous avons ainsi pu montrer l’importance du facteur de transcription Pea3 dans le contrôle des propriétés de migration, d’invasion et de prolifération des cellules cancéreuses TAC et MMT. En accord avec ces données, la recherche des gènes dont l’expression est régulée par Pea3 dans nos deux modèles cellulaires suite à la modulation de Pea3, a permis d’identifier de nombreux gènes capables de réguler la prolifération, la migration et l’invasion des cellules. Parmi ces gènes nous nous sommes intéressés au gène cycline d2 bien connu pour son implication dans le contrôle de la progression du cycle cellulaire. Nous avons pu montrer que le gène cycline d2 est un gène cible direct du facteur de transcription Pea3 qui module l’expression dans le modèle cellulaire TAC des deux transcrits (cycline d2 et cycline d2 trc) issus de ce gène et décrits à ce jour. L’étude de la fonction des protéines Cycline D2 et Cycline D2 Trc dans les cellules TAC a été entreprise. Tout d’abord la surexpression de l’une ou l’autre de ces isoformes dans les cellules TAC 2.1 modifie de façon opposée leur capacité à s’organiser dans un gel de collagène mimant l’environnement d’une glande mammaire, la Cycline D2 réprimant cette capacité et la Cycline D2 Trc l’augmentant. L’utilisation de petits ARN interférents permettant de réprimer l’expression de ces deux protéines a permis de montrer une relation fonctionnelle, toujours opposée, des deux isoformes avec le facteur de transcription Pea3 pour le contrôle de la progression du cycle cellulaire mais aussi pour l’induction d’une transition épithélio-mésenchymateuse étroitement reliée au pouvoir de migration des cellules épithéliales lors du développement des organes comme la glande mammaire mais aussi lors de la progression tumorale. Notre étude a ainsi permis de mieux définir l’implication du facteur de transcription Pea3 lors des événements de morphogenèse et de tumorigenèse de la glande mammaire. De plus elle ouvre la réflexion sur le rôle du gène cycline d2 lors de ces événements. / "Proteins of the PEA3 group (Pea3, Erm and Er81) belong to the ETS family of transcription factors. They are expressed in organs that undergo an epithelial branching morphogenesis process such as the lungs and the mammary gland. Moreover, in these organs, they are aberrantly expressed during cancer progression. Indeed, during breast cancer high Pea3 or Erm expression is respectively associated with cancer metastatic potential and a lower patient survival rate. Finally, as transcription factors they control the expression of specific genes called target genes. Even though some of these genes are known, more work is needed to understand the molecular mechanism governed by the PEA3 transcription factors. The main topic of my PhD is the study of the role of the Pea3 transcription factor during mammary morphogenesis and tumorigenesis using two complementary approaches: 1- characterize the morphogenetic properties that are controlled by Pea3 during the mammary morphogenesis and tumorigenesis events 2- find and characterize the genes that are regulated by Pea3 using a large scale transcriptomic analysis based on a microarray technology. The strategy is based on the utilization of two main cell lines in which we modulate Pea3 expression: an epithelial cell line, model of mammary morphogenesis (TAC 2.1) in which we overexpress Pea3 and a cancer cell line, model of mammary tumorigenesis (MMT) in which Pea3 expression is knocked down by means of small interfering RNA sequences. During my PhD we showed that Pea3 controls the proliferation, invasion and migration properties of TAC 2.1 and MMT cells. In agreement with these data, the transcriptomic analysis after Pea3 expression modulation in these cells (overexpression or knockdown) demonstrate that a large proportion of the Pea3 regulated genes are already known players in the regulation of the proliferation, invasion and migration processes. Amongst these genes, we focused on the cyclin d2 gene which is a well characterized actor in cell cycle progression and cell proliferation. We showed that cyclin d2 is direct Pea3 target gene. The cyclin d2 gene gives rise to two different isoforms generated by a splicing event (Cyclin D2 and Cyclin D2 Trc) that are both regulated by Pea3 at the mRNA and protein levels. We then evaluated the function of these two isoforms in the mammary epithelial cell line TAC 2.1. Overexpression of these proteins in the TAC2.1 cells leads to a modification, in an opposite fashion, of their ability to grow and organize in 3D structures within a collagen envirronement. The Cyclin D2 and the Cyclin D2 Trc respectively repressing and enhancing these abilities. The use of small interfering RNA sequences targeting specifically one or the other isoform allowed us to show a functional link between both isoforms and the Pea3 transcription factor , again in an opposite way, especially during cell cycle progression and during epithelial to mesenchymal conversion, a hallmark of development and cancer progression. Thus, this study gives new clues to understand the involvement of the Pea3 transcription factor during mammary morphogenesis and tumorigenesis, events in which the cyclin d2 gene seems to be a major player. The characterization of the molecular events governed by Pea3 should help in defining new therapeutic strategies against breast cancer progression. "

Even though polyomaviruses have been intensively studied for more than 60 years, the role of minor structural proteins VP2 and VP3 in some important steps of viral life cycle has still not been fully elucidated, explicitly their role in viral genome delivery to the cell nucleus and their involvement in late phases of viral life cycle. This diploma thesis focuses on the study of minor proteins of Mouse polyomavirus (MPyV) and Human polyomavirus BK (BKV). Four rabbit polyclonal antibodies against minor proteins of polyomaviruses MPyV or BKV have been prepared within this diploma thesis. Two of these prepared antibodies target minor proteins of MPyV (α-MPyV VP2/3) or BKV virus (α-BKV VP2/3), other two prepared antibodies recognize C-terminal sequence common to minor proteins VP2 and VP3 of MPyV (α-MPyV C-termVP2/3) or BKV virus (α-BKV C-termVP2/3). In the second part of this diploma thesis we aimed to study toxicity of BKV virus minor proteins during individual production in mammalian cells. Obtained results suggest that minor proteins of BKV virus might not exhibit as high levels of cytotoxicity as minor proteins of MPyV virus. Third part of this diploma thesis is devoted to investigation of interactions of BKV and MPyV minor proteins with cellular proteins and within one another respectively....

INTRODUÇÃO: O BKPyV está associado à inflamação e perda da função do enxerto em pacientes transplantados renais. Nos pacientes transplantados renais, aproximadamente 40% dos receptores desenvolvem viruria pelo BKPyV em até 3 meses e 20% desenvolvem viremia em até 1 ano pós-transplante. Os pacientes que desenvolvem viremia têm o risco de evolução para nefropatia associada ao BKPyV (NABKPyV), com prevalência em torno de 1 a 10%, e evolução para perda do enxerto renal bastante variável, de 0 a 100%, dependendo dos estudos e das intervenções realizadas. Embora a vigilância de replicação do BKPyV seja recomendada, existem diferenças de metodologia e periodicidade entre as recomendações publicadas. Adicionalmente, tem sido discutida a importância do cut-off de viremia para o manejo clínico desses pacientes na prevenção de evolução para nefropatia. Os objetivos primários deste estudo foram determinar a prevalência de decoy cell na urina, viremia e viremia sustentada pelo BKPyV e NABKPyV, nos receptores de transplante renal do Serviço de Transplante Renal do HCFMUSP, e os possíveis fatores de risco associados à presença a viremia sustentada pelo BKPyV e NABKPyV. MÉTODOS: Trata-se de um estudo de coorte prospectivo no qual foram incluídos todos os receptores e os doadores de transplante renal intervivos submetidos a transplante de agosto de 2010 a dezembro de 2011. Todos os participantes foram avaliados no momento imediato pré-transplante e os receptores foram monitorados para detecção de viremia de BKPyV e desenvolvimento de NABKPyV durante o período de até 2 anos pós-transplante. Os receptores colheram amostras de urina mensalmente, durante o primeiro ano, e a cada 3 meses durante o segundo ano pós-transplante para a pesquisa de viruria (realizada por decoy cell e/ou q-PCR). A detecção de viruria indicava o início de monitorização mensal de viremia por q-PCR, viremia era mantida até obtenção de três amostras de viremia negativas consecutivas. A detecção da primeira viremia positiva deveria ser confirmada por uma segunda amostra colhida após intervalo de duas semanas; se o exame repetido confirmasse a viremia positiva, os pacientes eram submetidos à biópsia renal percutânea para investigação de NABKPyV. RESULTADOS: No período do estudo foram realizados 326 transplantes e foram incluídos 246 pacientes. A prevalência de viruria foi de 36,9%, a de viremia 22,3% e a de nefropatia 3,2%. O tempo médio entre o transplante e a viruria positiva pela decoy cell foi de 7,2 meses, entre o transplante e a viremia positiva de 7,6 meses, e entre o transplante e o diagnóstico de NABKPyV de 8,5 meses. O único fator de risco encontrado para viremia sustentada e para nefropatia foi gênero masculino. O valor de cut-off de viremia que melhor discrimina a evolução para NABKPyV foi 44.955 cópias/mL. CONCLUSÕES: As prevalências de viruria, viremia e nefropatia foram semelhantes às reportadas na literatura. O gênero masculino foi o único fato de risco encontrado para viremia sustentada e nefropatia. O valor de cut-off de viremia que melhor discrimina o risco de evolução para nefropatia foi maior que o valor usualmente recomendado pela literatura, que é de 10.000 cópias/mL / INTRODUCTION: BKPyV is associated with inflammation and loss of graft function in kidney transplant patients. In kidney transplantation, approximately 35-47% of recipients develop viruria by BKPyV within 3 months post-transplantation, and 20% develop viremia within one year post-transplantation. Patients who develop viremia are at risk of progression to BKPyV-associated nephropathy (BKPyVAN), with prevalence around 1 to 10%, and a quite variable prevalence of progression to kidney graft loss, ranging from 0 to 100%, depending on the studies and the interventions. Although BKPyV surveillance is recommended, there are differences in methodology and frequency between published recommendations. In addition, the importance of viremia cutoff for clinical management of these patients in the prevention of progression for nephropathy has been discussed. The objectives of this study were to determine the prevalence of decoy cell in urine, BKPyV viremia, BKPyV sustained viremia, and BKPyVAN, in kidney transplant recipients of HCFMUSP Kidney Transplant Service. Additionally, the aim was to determine the possible risk factors associated with the presence of BKPyV sustained viremia and BKPyVAN. METHODS: This is a prospective cohort study. From August 2010 to December 2011, all recipients and donors of kidney transplant who underwent transplantation were enrolled. All participants were evaluated at immediate pre-transplant and recipients were monitored for detection of BKPyV viremia and development of BKPyVAN for up to two years post-transplantation. All recipients collected urine samples monthly during the first year and every three months during the second year post-transplant for viruria screening (performed by decoy cell and/or q-PCR). Viruria detection indicated the initiation of monthly viremia monitoring by q-PCR. Viremia was maintained until three consecutive negative viremia samples were obtained. The detection of the first positive viremia should be confirmed by a second sample collected after a two-week interval. If repeated examination confirmed positive viremia, the patients underwent percutaneous kidney biopsy to investigate BKPyVAN. RESULTS: During the study period, 326 transplants were performed and 246 patients were included. The prevalence of viruria, viremia, and nephropathy was, respectively, 36.9%, 22.3%, and 3.2%. The mean time between transplantation and positive viruria by decoy cell was 7.2 months, between transplantation and positive viremia was 7.6 months, and between transplantation and diagnosis of BKPyVAN was 8.5 months. The only risk factor for sustained viremia and nephropathy was male. Viremia cutoff value that best discriminates the progression to BKPyVAN was 44,955 copies/mL. CONCLUSIONS: The prevalence of viruria, viremia, and nephropathy were similar to those reported in the literature. Male was the only risk factor found for sustained viremia and nephropathy. Viremia cutoff value that best discriminates the risk of progression to nephropathy was greater than the value usually recommended in the literature, which is 10,000 copies/mL

INTRODUÇÃO: O BKPyV está associado à inflamação e perda da função do enxerto em pacientes transplantados renais. Nos pacientes transplantados renais, aproximadamente 40% dos receptores desenvolvem viruria pelo BKPyV em até 3 meses e 20% desenvolvem viremia em até 1 ano pós-transplante. Os pacientes que desenvolvem viremia têm o risco de evolução para nefropatia associada ao BKPyV (NABKPyV), com prevalência em torno de 1 a 10%, e evolução para perda do enxerto renal bastante variável, de 0 a 100%, dependendo dos estudos e das intervenções realizadas. Embora a vigilância de replicação do BKPyV seja recomendada, existem diferenças de metodologia e periodicidade entre as recomendações publicadas. Adicionalmente, tem sido discutida a importância do cut-off de viremia para o manejo clínico desses pacientes na prevenção de evolução para nefropatia. Os objetivos primários deste estudo foram determinar a prevalência de decoy cell na urina, viremia e viremia sustentada pelo BKPyV e NABKPyV, nos receptores de transplante renal do Serviço de Transplante Renal do HCFMUSP, e os possíveis fatores de risco associados à presença a viremia sustentada pelo BKPyV e NABKPyV. MÉTODOS: Trata-se de um estudo de coorte prospectivo no qual foram incluídos todos os receptores e os doadores de transplante renal intervivos submetidos a transplante de agosto de 2010 a dezembro de 2011. Todos os participantes foram avaliados no momento imediato pré-transplante e os receptores foram monitorados para detecção de viremia de BKPyV e desenvolvimento de NABKPyV durante o período de até 2 anos pós-transplante. Os receptores colheram amostras de urina mensalmente, durante o primeiro ano, e a cada 3 meses durante o segundo ano pós-transplante para a pesquisa de viruria (realizada por decoy cell e/ou q-PCR). A detecção de viruria indicava o início de monitorização mensal de viremia por q-PCR, viremia era mantida até obtenção de três amostras de viremia negativas consecutivas. A detecção da primeira viremia positiva deveria ser confirmada por uma segunda amostra colhida após intervalo de duas semanas; se o exame repetido confirmasse a viremia positiva, os pacientes eram submetidos à biópsia renal percutânea para investigação de NABKPyV. RESULTADOS: No período do estudo foram realizados 326 transplantes e foram incluídos 246 pacientes. A prevalência de viruria foi de 36,9%, a de viremia 22,3% e a de nefropatia 3,2%. O tempo médio entre o transplante e a viruria positiva pela decoy cell foi de 7,2 meses, entre o transplante e a viremia positiva de 7,6 meses, e entre o transplante e o diagnóstico de NABKPyV de 8,5 meses. O único fator de risco encontrado para viremia sustentada e para nefropatia foi gênero masculino. O valor de cut-off de viremia que melhor discrimina a evolução para NABKPyV foi 44.955 cópias/mL. CONCLUSÕES: As prevalências de viruria, viremia e nefropatia foram semelhantes às reportadas na literatura. O gênero masculino foi o único fato de risco encontrado para viremia sustentada e nefropatia. O valor de cut-off de viremia que melhor discrimina o risco de evolução para nefropatia foi maior que o valor usualmente recomendado pela literatura, que é de 10.000 cópias/mL / INTRODUCTION: BKPyV is associated with inflammation and loss of graft function in kidney transplant patients. In kidney transplantation, approximately 35-47% of recipients develop viruria by BKPyV within 3 months post-transplantation, and 20% develop viremia within one year post-transplantation. Patients who develop viremia are at risk of progression to BKPyV-associated nephropathy (BKPyVAN), with prevalence around 1 to 10%, and a quite variable prevalence of progression to kidney graft loss, ranging from 0 to 100%, depending on the studies and the interventions. Although BKPyV surveillance is recommended, there are differences in methodology and frequency between published recommendations. In addition, the importance of viremia cutoff for clinical management of these patients in the prevention of progression for nephropathy has been discussed. The objectives of this study were to determine the prevalence of decoy cell in urine, BKPyV viremia, BKPyV sustained viremia, and BKPyVAN, in kidney transplant recipients of HCFMUSP Kidney Transplant Service. Additionally, the aim was to determine the possible risk factors associated with the presence of BKPyV sustained viremia and BKPyVAN. METHODS: This is a prospective cohort study. From August 2010 to December 2011, all recipients and donors of kidney transplant who underwent transplantation were enrolled. All participants were evaluated at immediate pre-transplant and recipients were monitored for detection of BKPyV viremia and development of BKPyVAN for up to two years post-transplantation. All recipients collected urine samples monthly during the first year and every three months during the second year post-transplant for viruria screening (performed by decoy cell and/or q-PCR). Viruria detection indicated the initiation of monthly viremia monitoring by q-PCR. Viremia was maintained until three consecutive negative viremia samples were obtained. The detection of the first positive viremia should be confirmed by a second sample collected after a two-week interval. If repeated examination confirmed positive viremia, the patients underwent percutaneous kidney biopsy to investigate BKPyVAN. RESULTS: During the study period, 326 transplants were performed and 246 patients were included. The prevalence of viruria, viremia, and nephropathy was, respectively, 36.9%, 22.3%, and 3.2%. The mean time between transplantation and positive viruria by decoy cell was 7.2 months, between transplantation and positive viremia was 7.6 months, and between transplantation and diagnosis of BKPyVAN was 8.5 months. The only risk factor for sustained viremia and nephropathy was male. Viremia cutoff value that best discriminates the progression to BKPyVAN was 44,955 copies/mL. CONCLUSIONS: The prevalence of viruria, viremia, and nephropathy were similar to those reported in the literature. Male was the only risk factor found for sustained viremia and nephropathy. Viremia cutoff value that best discriminates the risk of progression to nephropathy was greater than the value usually recommended in the literature, which is 10,000 copies/mL

Interleukin 15 has great application potential such as in the biological treatment of cancer. It is involved in a variety of immunological processes, the most important of these involve influencing and induction of NK cells and T-lymphocytes proliferation. However, its therapeutic usages are limited by a low stability and short half-life. For this reason, there are various approaches of stabilization and expansion of its biological activity being explored. In this work, we analysed and developed a new approach, which uses viral nanostructures derived from major capsid VP1 protein of mouse polyomavirus as a carrier of IL-15. Moreover, VP1 proteins can be relatively easily modified and they are also capable to penetrate into the tumour cells. There were prepared two variants of IL-15 together with control nanostructures in the baculovirus expression system, one was composed of IL-15 and the other of the IL-15 fusion protein and truncated variant of VP1. Protein constructs were characterized by electron microscopy and biochemical methods. The total protein yield of VP1ΔC-IL15-HIS fusion variant was higher (up to 53 mg/L of complete medium) than IL-15 alone (8,5 mg/L). However, testing of the biological activity of the prepared proteins in vitro did not show any induction of proliferation on Jurkat...

No description available.

Mouse polyomavirus (MPyV) is a non-enveloped DNA tumor virus, which replicates in the host cell nucleus. MPyV enters cells by receptor-mediated endocytosis and its subsequent transport towards the nucleus requires acidic environment of endosomes and intact microtubules, which are important for virus delivery to endoplasmic reticulum (ER). In ER, capsid disassembly and uncoating of viral genome take place. The mechanism of subsequent translocation of viral genome from ER into nucleoplasm is still only poorly understood process with predicted involvement of cellular factors and viral minor capsid proteins VP2 and VP3. Once the genome appears in the nucleus, early viral antigens are produced and mediate suitable environment for replication of viral genomes. After replication of viral DNA and morphogenesis of virions, virus progeny is released from the cells during its lysis. The research presented in the first part of thesis focused on intracellular transport of MPyV and involvement of cytoskeletal networks during virus delivery to the ER. In particular, we investigated still unclear role of microtubules during virus trafficking in endosomes, and involvement of microtubular motors. We found that MPyV trafficking leading to productive infection does not require the function of kinesin-1 and kinesin-2,...

Mouse polyomavirus (MPyV) is small non-enveloped DNA virus. Although this virus has been studied for almost 60 years, it still remains unclear, how can virus transport its genetic information to the cell nucleus. Also, the mechanism of virion morphogenesis is not well understood. First part of this work is focused on endocytic pathway which is used by MPyV for trafficking toward the cell nucleus. Using dominant negative mutant of caveolin-1 we showed that caveolin-1dependent endocytic pathway, described for SV40, is not used by MPyV for productive infection. MPyV is transported to early endosomes. Acidic milieu of endosomes is indispensable for productive infection. Preventing virus localisation into early endosomes (dominant negative mutant of Rab 5 GTPase) or endosomes alkalisation (by ammonium chloride or bafilomycin A1) led to dramatic decrease of virus infectivity. Alkalisation of endosomes entailed retention of MPyV in early endosomes. It indicates that virus is further transported to late endosomes. Finally, we confirmed by FRET that MPyV is in perinuclear space localized into recycling endosomes. Another poor characterized process is virion morphogenesis. To characterize the participation of cellular proteins in virion precursor complexes, nuclear as well as whole-cell lysates of infected cells or...

and key words Mouse polyomavirus-derived virus-like particles composed from major capsid protein VP1 (MPyV VP1-VLPs) are interesting structures for use as a delivery system of various cargos into cells. VP1 protein self-assembles into icosahedral particles of 45 nm in diameter that are hollow highly regular nanoparticles. In this work, model small molecule cargo, Cyclodextrin-Based Bimodal Fluorescence/MRI Contrast Agent, was encapsidated into MPyV VP1-VLPs. The cargo was stably associated with VLPs and was delivered into mammalian cells using these VLPs. To prevent VLPs entrapment in endolysosomal compartments and increase the potential of VLPs applications, MPyV VP1 protein was modified by insertion of histidine-tag (6 histidine long sequence surrounded by glycine and serine) sequences into VP1 surface loop DE, because histidine modification of synthetic systems had enhancing effect on endosome escape and cargo delivery. With the use of in Bac-to-Bac® baculovirus expression system His-VP1 protein was expressed in insect cells and a variety of VP1-assemblies was obtained: long tubules and small 20nm VLPs formed from VP1 with 4 histidine-tags in DE loop, and novel VP1 nanostructure, which we named nano-jumpers, formed from VP1 with 2 histidine-tags. Nonetheless the endosome escape properties of...

nÃo hà / O poliomavirus tipo BK tem sido associado à nefropatia nos pacientes transplantados renais com uma incidÃncia variando entre 3 - 4% e em 60% dos casos podendo levar à perda do enxerto. Diversos estudos tÃm demonstrado a importÃncia do achado da cÃlula decoy na urina destes pacientes como primeira triagem para a replicaÃÃo viral fazendo o diagnÃstico diferencial entre a rejeiÃÃo celular aguda e a nefropatia pelo BK vÃrus. Neste contexto, o presente estudo objetivou detectar a presenÃa do BKV atravÃs da observaÃÃo da cÃlula decoy na urina dos transplantados renais, correlacionando este achado com os nÃveis sÃricos de urÃia e creatinina e o aspecto histopatolÃgico atravÃs da biÃpsia renal. Para tanto, a urina de 50 pacientes transplantados renais (28 homens e 22 mulheres) atendidos em dois hospitais de Fortaleza (Hospital UniversitÃrio Walter CantÃdio e Hospital Geral de Fortaleza) foram analisadas quanto à presenÃa de cÃlulas decoy detectadas atravÃs da citologia urinÃria pela coloraÃÃo de Papanicolau. As citologias foram analisadas e classificadas em negativa e positiva (&#8805; 1 cÃlula decoy). Resultado: Das 50 citologias urinÃrias analisadas 28 pacientes eram do sexo masculino e 22 do sexo feminino, receptores de doador vivo (n = 43) ou cadavÃrico (n = 7) com positividade para cÃlula decoy de 24% (12 pacientes). NÃveis de creatinina e urÃia aumentados, isoladamente, nÃo foram Ãteis para suspeitar da nefropatia pelo BKV ou rejeiÃÃo do transplante (p > 0,05). A correlaÃÃo dos nÃveis alterados de urÃia e creatinina, com a presenÃa ou ausÃncia das cÃlulas decoy, foi estatisticamente significativa (p < 0,05). A biÃpsia revelou nefropatia pelo BKV em cinco (20%) dos pacientes com cÃlulas decoy na urina e os achados histolÃgicos mais freqÃentes foram fibrose e infiltrado inflamatÃrio mononuclear. A imunossupressÃo mais empregada nos pacientes em estudo foi o esquema 1 (50%) (ciclosporina / azatioprina / zenapx), seguidos por esquemas 2 (16%) (MMF/FK 506 / zanapax) 1 esquema 3 (16%) (ciclosporina / prednizona / azatioprina). ConclusÃo: A positividade para cÃlulas decoy neste estudo (24%) à coincidente com a literatura (8 -26%) sugerindo infecÃÃo ativa. A presenÃa das cÃlulas decoy na urina foi Ãtil para definir os grupos de pacientes com possÃvel nefropatia pelo BKV daqueles com nefropatia por rejeiÃÃo, pois a negatividade para cÃlulas decoy na urina afasta em 100% dos casos a nefropatia pelo BKV, e a sua presenÃa serve de guia para avanÃar na investigaÃÃo de nefropatia pelo BKV. A biÃpsia confirmou em 5 dos 12 casos com cÃlulas decoy positivas na urina (20%) a nefropatia pelo poliomavirus sendo que um deles veio a perder o enxerto. O esquema de imunossupressÃo utilizado pelos pacientes em estudo e a presenÃa de nefropatia pelo BKV nÃo foi o que mais se relaciona na literatura. TambÃm os pacientes com nefropatia pelo BKV que utilizaram esquemas menos associados a esta condiÃÃo tiveram evoluÃÃo pior. Estes Ãltimos resultados indicam a necessidade de novos estudos com maior nÃmero de pacientes, tempo de acompanhamento maior e estudo das cepas virais. / The polyomavirus type BK has been associated to the nephropathy in the patients transplanted renal with an incidence varying among 3 - 4% and in 60% of the cases could take to the loss of the graft. Several studies have been demonstrating the importance of the discovery of the decoy cells in these patients' urine as first selection for the viral replication making it diagnose differential between the sharp cellular rejection and the nephropathy for the BK virus. In this context, the present study aimed at to detect the presence of BKV through the observation of the decoy cells in the urine of the transplanted renal, correlating this discovery with the serum urea levels and creatinine and the histopathology features through the renal biopsy. For so much, the 50 transplanted patients' urine renal (28 men and 22 women) assisted at two hospitals of Fortaleza (Academical Hospital Walter CantÃdio and General Hospital of Fortaleza) they were analyzed as for the presence of decoy cells detected through the urinary cytology by the coloration of Papanicolau. Were the cytology analyzed and done classify in negative and positive (&#8805; 1 decoy cell). Result: Of the 50 cytology analyzed urinary 28 patients they were male and 22 female, alive donor's receivers (n = 43) or cadaverous (n = 7) with assertiveness for decoy cells of 24% (12 patient). Creatinine levels and increased urea, separately, they were not useful to suspect of the nephropathy for BKV or rejection of the transplant (p > 0,05). The correlation of the altered levels of urea and creatinine, with the presence or absence of the decoy cells, was significant for the statistics (p < 0,05). The biopsy revealed nephropathy for BKV in five (20%) of the patients with cells decoy in the urine and the more frequent histological discoveries were fibrose and infiltrated inflammatory mononuclear. The most employed immune suppression in the patients in study was the outline 1 (50%) (ciclosporina / azatioprina / zenapx), following for outlines 2 (16%) (MMF/FK 506/zanapax) 1 outline 3 (16%) (ciclosporina / prednizona / azatioprina). Conclusion: The assertiveness for decoy cells in this study (24%) it is coincident with the literature (8 -26%) suggesting active infection. The presence of the decoy cells in the urine was useful to define the patients' groups with possible nephropathy for BKV of those with nephropathy for rejection, because the negativity for decoy cells in the urine moves away in 100% of the cases the nephropathy for BKV, and his/her presence serves as guide to move forward in the nephropathy investigation for BKV. The biopsy confirmed in 5 of the 12 cases with decoy cells positive in the urine (20%) the nephropathy for the polyomavirus and one of them vein to lose the graft. The immunosuppressive outline used by the patients in study and the nephropathy presence for BKV was not it that more it links in the literature. Also the patients with nephropathy for BKV that used less associated outlines this condition had worse evolution. These last results indicate the need of new studies with larger number of patients, time of larger attendance and study of the stumps turn.