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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Estudo da atividade leishmanicida de derivados dialquilfosforilhidrazonas / Study of leishmanicidal activity of dialkylphosphorylhydrazone derivatives

Matta, Carolina Barbosa Brito da 29 February 2016 (has links)
Leishmaniasis is a worldwide neglected disease with high impact among the underprivileged population, especially in developing countries. The therapeutic arsenal is limited, outdated and causes serious side effects and can even cause death. In addition, studies show that there is great resistance of the parasite to treatment. In this regard, 18 (4a - 4o) new dialkylphosphorylhydrazones compounds were synthesized and evaluated against the parasites Leishmania species. Initially, we evaluated the effect of these compounds against L. amazonensis and L. braziliensis promastigotes in vitro. It was observed that all of compounds showed activity against these parasite, except 4a, 4c and 4e. In order to assess a potential toxicity against mammalian cells, MTT assay were performed in J774 macrophages treated with compounds. All The compounds showed low cytotoxicity with LC50 values >100 mM, except for 4o, which was toxic to approximately 20% of the treated cells. Using the EC50, Emax and cytotoxicity parameters, 4m and 4n compounds were chosen for the subsequent tests. These compounds were tested antiamastigote assay in vitro. In this test, the average of the number of parasites per macrophage, the percentage of infected macrophages and infection index of L. amazonensis-infected macrophages were reduced dose dependently by both compounds, similar to standard drug miltefosine. Since these compounds showed anti-leishmania activity in vitro, later it was tested 4m and 4n anti-leishmania effect in mouse model of cutaneous leishmaniasis, that mimics human disease. In this assay, the oral treatment with both compounds caused a complete healing of nodules and ulcers in L. amazonensis-infected mice ears, but the control of parasite burden at the inoculation site was reduced only in the case of treatment with 4n. On the other hand, none of two compounds interfered in systemic parasite burden, once they did not reduce parasite levels in draining lymph nodes. Thereafter, we also evaluate 4m and 4n effect in L. chagasi-induced visceral leishmaniasis in hamsters (Mesocricetus auratus). Firstly, in vitro assays against promastigotes and amastigotes form of L. chagasi were performed. Similar to observed previously, 4m and 4n were active against both L. chagasi forms. In addition, by scanning electron microscopy, it was observed that promastigotes treated with 4m compound presented multiple flagellae, aberrant shapes and multi-septation; while 4n treatment caused cell body shrinkage and multi-septation. In in vivo test, 15 days after oral treatment with 4m and 4n, it was evaluated the visceral organs weight (spleen and liver). Despite this treatment did not reduce organs weight, it reduced the parasite burden in spleen, which indicate oral effect of 4m and 4n against visceral leishmaniasis in mice. Also, it was observed that 4m and 4n treatment did not induce hepatotoxicity and nephrotoxicity, since they did not increase the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea and creatinine. Taken together, these data indicate that dialkylphosphorylhydrazones compounds are active against Leishmania species, mainly 4m and 4n compunds, which are orally active against cutaneous and visceral leishmanisis. This indicate that 4m and 4n could be new lead compounds therapeutically useful against leishmaniasis. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A leishmaniose é uma doença negligenciada mundialmente com alto impacto dentre a população menos favorecida, principalmente em países em desenvolvimento. O arsenal terapêutico é restrito, ultrapassado e provoca efeitos adversos graves, podendo causar até a morte. Além disso, estudos mostram que há grande resistência do parasita ao tratamento. Nesse sentido, foram racionalmente planejados e sintetizados 18 novos derivados dialquifosforilhidrazonas (4a - 4o) e avaliados contra espécies de Leishmania. Inicialmente, foi avaliado o efeito desses compostos contra formas promastigotas de L. amazonensis e L. braziliensis in vitro. Observou-se que todos os compostos apresentaram atividade contra esses parasitos, exceto os compostos 4a, 4c e 4e. Para avaliar a toxicidade destes compostos contra células de mamíferos, foi realizado o ensaio de MTT em macrófagos J774. Nesse ensaio nenhum derivado apresentou citotoxicidade na concentração avaliada (100 mM), exceto 4o, que foi tóxico para aproximadamente 20% das células tratadas. Em seguida, utilizando os parâmetros de CI50, Emax e citotoxicidade, foram escolhidos os compostos 4m e 4n para os testes subsequentes. Esses compostos foram avaliados in vitro no ensaio de amastigota. Nesse teste, a média do número de parasitas por macrófago, a porcentagem de macrófagos infectados e o índice de infecção dos macrófagos por L. amazonensis foram reduzidos de forma dependente de dose por ambos os compostos, semelhante ao fármaco padrão Miltefosina. Uma vez que estas moléculas apresentaram atividade leishmanicida in vitro, foi avaliado o efeito de 4m e 4n no modelo de leishmaniose cutânea em camundongos, que mimetiza a doença em humanos. O tratamento oral com ambos os compostos promoveu a cicatrização total de nódulos e úlceras nas orelhas de camundongos infectados com L. amazonensis, porém apenas o tratamento com 4n reduziu a carga parasitária no local do inóculo. Além disso, nenhum dos compostos interferiu na carga parasitária sistêmica, uma vez que eles não reduziram os níveis dos parasitas nos linfonodos drenantes. O efeito de 4m e 4n foi também avaliado contra L. chagasi, causadora da forma visceral da doença. Inicialmente, foram realizados ensaios in vitro contra as formas promastigotas e amastigotas de L. chagasi. Semelhante ao que foi observado anteriormente, 4m e 4n foram ativos contra ambas as formas de L. chagasi. Além disso, por meio de microscopia eletrônica de varredura, observou-se que as formas promastigotas tratadas com 4m apresentaram múltiplos flagelos, formas anômalas e múltiplos septos, enquanto o tratamento com 4n induziu uma redução do corpo celular das promastigotas e a formação de múltiplos septos. No modelo de leishmaniose visceral em hamsters (Mesocricetus auratus), 15 dias após os tratamentos, o peso dos órgãos viscerais (fígado e baço) foi avaliado. Embora esse tratamento não tenha reduzido o peso dos órgãos, reduziu a carga parasitária no baço, o que indica um efeito oral leishmanicida dos compostos 4m e 4n contra a forma visceral. Adicionalmente, foi observado que o tratamento com 4m e 4n não induziu hepatotoxicidade nem nefrotoxicidade, uma vez que os níveis de alanina transaminase (ALT), aspartato transaminase (AST), ureia e creatinina não estavam elevados após o tratamento. Em conjunto, esses dados indicam que os compostos dialquilfosforilhidrazonas são ativos contra espécies de Leishmania, principalmente os compostos 4m e 4n, que são foram ativos por via oral contra leishmaniose cutânea e visceral. Indicando que estes podem ser considerados novos protótipos para o tratamento da leishmaniose.
242

Avaliação da resposta imune específica de células TCD8+ e citocinas na tuberculose humana / Evaluation of specific immune response of TCD8+ cells and cytokines in human tuberculosis

Silva, Bruna Daniella de Souza 13 February 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-01-28T09:47:26Z No. of bitstreams: 2 Tese - Bruna Daniella de Souza Silva - 2015.pdf: 3849700 bytes, checksum: 267d28b0d91fc274ddb5bfd83ed08e5b (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-01-28T09:49:33Z (GMT) No. of bitstreams: 2 Tese - Bruna Daniella de Souza Silva - 2015.pdf: 3849700 bytes, checksum: 267d28b0d91fc274ddb5bfd83ed08e5b (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-01-28T09:49:33Z (GMT). No. of bitstreams: 2 Tese - Bruna Daniella de Souza Silva - 2015.pdf: 3849700 bytes, checksum: 267d28b0d91fc274ddb5bfd83ed08e5b (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Millions of people die every year due to tuberculosis (TB), an infectious disease that have effective treatment, can be prevented and is curable. One of the greatest problems faced by this disease is the latent infection (LTBI), where individuals do not manifest clinical symptoms, is a reservoir of the causing agent, Mycobacterium tuberculosis (Mtb), and can reactive the disease at any time during their life span. Moreover, TB can affect any organ in the body, such as the skin, causing extrapulmonary TB, a rare form of TB, the TB skin. Some of these forms may be more severe than pulmonary TB, causing serious consequences to the patient, contributing to the high mortality rate of this disease. In this context, understanding the immunological events related to the interaction between pathogen and host the development of active disease or latent infection is a crucial point that can contribute to the control of TB. Thus, the objectives of this study were to evaluate the specific immune response of CD8+ T cells and cytokines in cutaneous tuberculosis, latent and active pulmonary TB. Thirty six patients with pulmonary TB, one patient with cutaneous TB and 36 healthy controls, classified as LTBI (N = 13) or negative (TST-, N = 23) by the tuberculin skin test were recruited and the peripheral blood mononuclear cells, plasma and sera from those individuals were collected to perform flow cytometry, ELISA and multiplex bead array analysis. It was observed that patients with active pulmonary TB presented TCD8+ cells with a regulatory profile, expressing IL-10 and TGF-β in a direct relation to the bacillary load. The same profile was observed in the individual with cutaneous TB, an extra-pulmonary form of TB. The findings observed in this studyco nclude that Mtb can modulate CD8+ T cell response in lung and skin tuberculosis, demonstrating the importance of studies assessing the immune interaction between the pathogen and the host. / A tuberculose (TB) é uma doença causada por Mycobacterium tuberculosis, principal agente etiológico da TB humana. Milhões de pessoas morrem todo ano em decorrência da TB, doença infecciosa que tem prevenção, tratamento e cura. Um dos maiores problemas enfrentados com essa doença é a infecção latente (TBIL), onde o indivíduo não manifesta os sintomas clínicos e constitui um reservatório da bactéria, podendo desenvolver a doença ativa em qualquer momento. Além disso, a TB pode afetar qualquer órgão do corpo, como por exemplo, a pele, causando uma forma rara de TB extrapulmonar, a TB cutânea. Algumas dessas formas podem ser mais severas que a TB pulmonar, trazendo consequências graves ao paciente, contribuindo para o alto índice de mortalidade dessa enfermidade. Nesse contexto, entender os eventos imunológicos relacionados à interação entre patógeno e o hospedeiro no desenvolvimento da doença ativa ou da infecção latente é um ponto crucial que pode contribuir para o controle da TB. Diante disso, os objetivos desse trabalho foram avaliar a resposta imune específica de células TCD8+ e citocinas na tuberculose cutânea, latente e pulmonar ativa. Para isso, foram recrutados 36 pacientes com TB pulmonar ativa, 01 paciente com TB cutânea e 36 controles sadios classificados quanto à prova tuberculínica em indivíduos com infecção latente (TBIL = 13) ou não (PT-=23). Foram obtidas, de todos os pacientes, as células mononucleares do sangue periférico, o plasma e o soro para realização dos ensaios de citometria de fluxo e ELISA. Foi observado que os pacientes com TB pulmonar ativa apresentam um perfil regulador de células TCD8+ específicas, com expressão de IL-10 e TGF-β relacionados com a carga bacilar quando comparado aos indivíduos com TBIL e controles sadios PT negativa. Esse mesmo perfil também foi observado e descrito no caso clínico do paciente com TB cutânea. Diante de todos os achados observados nesse trabalho podemos concluir que Mtb pode modular a resposta de células TCD8+ na tuberculose pulmonar e cutânea, demonstrando a importância de estudos que avaliem a interação imunológica entre o patógeno e o hospedeiro tais como este.
243

Leishmaniose Tegumentar Americana na região Centro-Oeste: avaliação de dados clínicos, epidemiológicos, laboratoriais e moleculares / Cutaneous Leishmaniasis in the Midwest region: review of clinical, epidemiological, laboratory and molecular data

Balian, Rosana Pereira Morais 30 April 2014 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-12-29T15:29:37Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Rosana Pereira Morais Balian - 2014.pdf: 11248041 bytes, checksum: c5e17257fc2aa971ce5615831d8147ae (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2014-12-29T15:36:56Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Rosana Pereira Morais Balian - 2014.pdf: 11248041 bytes, checksum: c5e17257fc2aa971ce5615831d8147ae (MD5) / Made available in DSpace on 2014-12-29T15:36:57Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Rosana Pereira Morais Balian - 2014.pdf: 11248041 bytes, checksum: c5e17257fc2aa971ce5615831d8147ae (MD5) Previous issue date: 2014-04-30 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Protozoa of the genus Leishmania, which affects the skin and/or mucous membranes, cause American Cutaneous Leishmaniasis (ACL). It is an endemic zoonosis whose numbers of cases in the Brazil Midwest region are growing. In the Goiás state, 2798 ACL cases were been reported between 2007 and 2013. In the present study, our proposal was to investigate the epidemiological and molecular characteristics of ACL patients attended at the ambulatory of the Hospital Anuar Auad in the period 2000 at 2006 and identify the species of Leishmania sp. The study included 152 patients with ACL, 124 were from of the state of Goiás and 28 at Mato Grosso, aged between 6-79 years, and center and thirteen these individuals were male. For diagnosis, clinical, epidemiological and laboratory data were collected, such as direct examination (ED), histopathology (AH), Montenegro skin test (MST), indirect immunofluorescence (IIF). ELISA using crude extract of L. (Viannia) braziliensis was performing. Characterization of Leishmania species was carried out by polymerase chain reaction (PCR). The positivity of ED, AH, MST, IIF and ELISA was 70.6%, 80.9%, 68.9%, 44.2% and 73.0%, respectively. Specific IgG to L. (V.) braziliensis were detecting in 84.7% of patients with mucosal leishmaniasis (ML), significantly higher than those found in patients with cutaneous leishmaniasis (CL), which was 69.0% (p < 0.05). Detection of IgG before and after treatment was performed using ELISA and was observed a statistically significant difference only in samples obtained from patients with CL after 6 and 18 months of treatment. The data serological monitoring of patients with ACL before and after treatment indicates that the total IgG levels tend to decrease after 6 months of treatment. PCR was performed on 69 samples obtained from scraping the edge of lesions of patients with ATL, these, 62 (89.8%) were positive, 53 patients with LC and 9 patients with ML. The samples were characterized by PCR as L. (V.) braziliensis (93.5%) and L. (L.) amazonensis (6.5%). It was found that 25.8% of cases of leishmaniasis in the state of Goiás occurred in Campestre, Goiânia, Aparecida de Goiânia and Niquelândia. By analyzing the frequency of cases of ATL over the months during the years analyzed, it was observed that there was a distribution of ACL in all seasons from 2000 to 2006, with a larger number of cases in winter. PCR represents important and powerful tool in the diagnosis and species identification in ACL in endemic areas. ACL controlling in endemic areas is difficult and requires an accurate idea of its epidemiology. / A leishmaniose tegumentar americana (LTA) é causada por protozoários do gênero Leishmania, que acomete pele e/ou mucosas. É uma zoonose endêmica, cujos números de casos na região Centro-Oeste são crescentes. No Estado de Goiás, foram notificados 2798 casos de LTA, entre os anos de 2007 e 2013. No presente trabalho a nossa proposta foi Investigar as características epidemiológicas e moleculares da LTA de pacientes atendidos no ambulatório de endemias do hospital Anuar Auad no período de 2000 a 2006 e identificar as espécies de Leishmania spp. Participaram do estudo 152 pacientes com LTA, 124 do Estado de Goiás e 28 do Mato Grosso, com faixa etária de 6 a 79 anos. Destes, 113 eram do sexo masculino. Para o diagnóstico foi realizada a avaliação clínicoepidemiológica e laboratorial, tais como exame direto (ED), análise histopatológica (AH), intradermorreação de Montenegro (IRM), imunofluorescência indireta (IFI) e ELISA utilizando extrato total de L. (Viannia) braziliensis. Foi feita a caracterização das espécies de leishmânias por reação em cadeia da polimerase (PCR). A positividade do ED, AH, IRM, IFI e ELISA foi de 70,6%, 80,9%, 68,9%, 44,2% e 73,0%, respectivamente. Foram detectadas IgG específica para L. (V.) braziliensis em 84,7% dos pacientes com leishmaniose mucosa (LM), sendo significativamente superiores às encontradas em pacientes com leishmaniose cutânea (LC), que foi de 69,0% (p<0,05). A detecção de IgG antes e após o tratamento foi feita utilizando ELISA e foi observado que apenas nas amostras dos pacientes com LC obtiveram uma diferença estatística significante após 6 e 18 meses de tratamento. Os dados do acompanhamento sorológico dos pacientes com LTA antes e após o tratamento indicam que os níveis de IgG total tendem a diminuir após 6 meses de tratamento. A PCR foi realizada em 69 amostras obtidas a partir de raspado das bordas das lesões de pacientes com LTA. Destes, 62 (89,8%) foram positivas, sendo 53 de pacientes com LC e nove de pacientes com LM. As amostras foram caracterizadas por PCR como Leishmania (V.) braziliensis (93,5%) e L. (L.) amazonensis (6,5%). Verificou-se que 25,8% dos casos de LTA no Estado de Goiás ocorreram em Campestre, Goiânia, Aparecida de Goiânia e Niquelândia. Ao analisar a frequência de casos de LTA ao longo dos meses durante os anos analisados, observou-se que houve uma distribuição de LTA em todas as estações do ano, com um maior número de casos no inverno. A PCR representa uma importante e poderosa ferramenta no diagnóstico e na identificação das espécies de LTA em áreas endêmicas. O controle da LTA em áreas endêmicas é difícil e requer uma ideia exata de sua epidemiologia.
244

Macrófagos polarizados M2 na resposta tecidual das lesões cutâneas da leishmaniose tegumentar americana / M2 polarized macrophages in tissue immune response in cutaneous lesions of American tegumentary leishmaniasis

Naiura Vieira Pereira 13 March 2018 (has links)
INTRODUÇÃO: A Leishmaniose Tegumentar Americana (LTA) é uma doença infecciosa endêmica no Brasil, causada por protozoários do gênero Leishmania e possui duas formas clínicas principais, a leishmaniose cutânea (LC) e a leishmaniose mucocutânea (LMC). Os macrófagos têm papel crucial na patogênese da Leishmaniose como hospedeiros do parasita e atuam como células apresentadoras de antígenos, promovendo uma resposta imune de perfil Th1 contra a Leishmania. Os macrófagos polarizados M2, relacionados com resposta anti-inflamatória (Th2), são envolvidos no controle da inflamação e dano tecidual em várias doenças e estão associados à cronicidade nas doenças infecciosas. O objetivo deste trabalho foi verificar a participação dos macrófagos M2 nos sítios de lesão cutânea da LTA MÉTODOS: Sessenta e três biópsias de pele de lesões de LTA, obtidas de 48 doentes com LC e 15 de LMC, foram submetidas ao método imuno-histoquímico com os anticorpos anti-CD163 e anti-CD206, marcadores de macrófagos M2. Dez espécimes foram também submetidos à técnica imuno-histoquímica de dupla marcação com a utilização dos marcadores pSTAT-1 e CD68 para identificação de macrófagos M1 e CMAF e CD163 para identificação de macrófagos M2. RESULTADOS: Os espécimes de pele com reação inflamatória difusa (n = 26) exibiram maior número de células imunomarcadas com CD163, quando comparadas ao grupo com reação granulomatosa bem organizada (n = 37) (p= 0,01). Os macrófagos CD163+ também foram mais numerosos nas lesões de pele com a presença de formas amastigotas de Leishmania (n = 39) ao exame histopatológico (p=0,02), quando comparadas às lesões onde os parasitas não foram observados (n = 24). O mesmo ocorreu quando comparados somente os espécimes do grupo de doentes com LC com a presença de parasitas (n = 31) e ausência dos mesmos (n = 17) (p = 0,04). As lesões de pele de doentes com LMC mostraram maior número de células CD206+ (n = 15) que a de doentes com LC (n = 48) (p=0,008). Houve correlação positiva entre o número de células imunomarcadas com os anticorpos CD163 e CD206 (r de Spearman= 0,369). Os macrófagos +pSTAT1/CD68+ (M1) mostraram-se mais numerosos que os macrófagos CMAF+/CD163+ (M2) nos sítios de lesão cutânea da LTA. CONCLUSÕES: Os resultados obtidos sugerem que os macrófagos M2 têm um papel na resposta imune \"in situ\" da LTA. Essas células devem atuar como células alvo, facilitando a entrada dos parasitas, a progressão da doença e parecem estar envolvidos nos mecanismos de cronicidade e nos processos de remodelamento tecidual dessa doença. As moléculas CD163 e CD206 podem ser consideradas bons marcadores teciduais de macrófagos M2, uma vez que mostraram correlação positiva em sua expressão. A técnica de dupla marcação confirmou a presença dos macrófagos M2 nas lesões cutâneas da LTA. Embora ocorra a presença de macrófagos M2, os macrófagos M1 são a população macrofágica predominante da resposta imune \"in situ\" da LTA / INTRODUCTION: American tegumentary leishmaniasis (ATL) is an endemic infectious disease in Brazil, caused by Leishmania parasites and it has two main clinical forms, cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (MCL). Macrophages play a key role in leishmaniasis pathogenesis. They are definite parasite host and act as antigen presenting cells, eliciting a Th1 pattern of immune response (M1) against Leishmania. M2 polarized macrophages, related to an anti-inflammatory response (Th2), are involved in controlling inflammation and tissue damage in several diseases and are related to chronicity in infectious diseases. The aim of this study was verifying M2 macrophages \"in situ\" participation in ATL. METHODS: Sixty-three skin biopsies from LTA lesions, obtained from patients with CL (n=48) and MCL (n=15), were subjected to imunohistochemical technique with M2 macrophages markers CD163 and CD206 antibodies. Ten samples were selected for double staining technique with pSTAT1 and CD68 markers for M1 identification, and CMAF and CD163 markers for M2 macrophages identification. RESULTS: Skin samples displaying diffuse inflammatory reaction (n = 26) exhibited higher number of CD163 immune stained macrophages when compared to the well-organized granulomatous reaction group (n = 37) (p=0.01). CD163+ macrophages were higher in samples displaying Leishmania parasites (n = 39) at histopathology exam than the samples without parasites (n = 24) (p=0.02). Same result was observed when comparing the lesions of CL lesions with (n = 31) and without (n = 17) parasites (p = 0.04). MCL skin lesions (n = 15) showed higher number of CD206+ cells (p = 0.008) in comparison with skin lesions taken from CL patients (n = 48). Spearman test demonstrated a positive correlation between the number of CD163+ and CD206+ immune stained cells (Spearman r = 0,369). M1 macrophages (pSTAT1+/CD68+) were present in higher number when compared to M2 macrophages (CMAF+/CD163+) in the samples studied. CONCLUSIONS: The results suggest that M2 macrophages play a role in the in situ immune response of ATL. M2 polarized macrophages may act as host target cells facilitating parasites entry and promoting disease progression, but also seem to be involved with chronicity and tissue remodeling of ATL lesions. CD163 and CD206 molecules may be considered as good markers for M2 macrophages. Double staining technique confirmed the presence of M2 macrophages, although M1 macrophages are the predominant macrophagic component in skin lesions of ATL
245

Micose fungóide foliculotrópica: descrição clínico-epidemiológica, análise histológica e investigação do colapso do imunoprivilégio do folículo piloso / Folliculotropic mycosis fungoides: clinical and epidemiological description, histological analysis and investigation of hair follicle immune privilege collapse

Janyana Marcela Doro Deonizio 27 April 2015 (has links)
Introdução: A micose fungóide foliculotrópica (MFF) é subtipo de linfoma cutâneo de células T que atinge especialmente o folículo piloso e parece ter prognóstico mais reservado. Informações clínicas sobre a população acometida por linfomas cutâneos no Brasil são escassas. O fenômeno de imunoprivilégio (IP) diz respeito à habilidade de alguns órgãos em permanecer protegidos contra reações inflamatórias. Tem sido sugerido que o folículo piloso normal represente um local de IP. Nesse estudo aventou-se a possibilidade de haver uma quebra no equilíbrio desse fenômeno na MFF, com alteração na expressão de moléculas do complexo maior de histocompatibilidade (MHC) e na expressão de MHC não-clássicos (HLA-G), com algum papel no mecanismo do foliculotropismo. Os objetivos foram: descrever o perfil clínico-epidemiológico de paciente com MFF, descrever a histologia e imunofenótipo dos casos de MFF e investigar os mecanismos envolvidos na predileção dos linfócitos atípicos pelo folículo piloso. Metodologia: Os prontuários de pacientes com diagnóstico de MFF provenientes do ambulatório de Linfomas Cutâneos da Faculdade de Medicina da Universidade de São Paulo (FMUSP) foram revisados (n=33). O material histológico de biópsias de pele dos pacientes com MFF provenientes dos ambulatórios de Linfomas Cutâneos da FMUSP e da Northwestern University foi analisado por meio de escala semi-quantitativa (n=43). Na coloração de hematoxilina-eosina foram avaliados os seguintes parâmetros: infiltrado neoplásico epidérmico, infiltrado neoplásico dérmico, presença de acantose/espongiose, de mucinose folicular, de fibroplasia do tecido conjuntivo, de eosinófilos, de plasmócitos, o tamanho celular e o grau de dano folicular. Analisou-se a positividade do infiltrado neoplásico para os seguintes marcadores celulares: CD1a, CD56, TIA-1 e CD117. As expressões do complexo de histocompatibilidade HLA-G e do MHCII no infiltrado celular e no epitélio folicular foram investigadas no grupo de pacientes com MFF e comparadas com o grupo de pacientes com micose fungóide clássica (MFC) e pele normal. A expressão do complexo de histocompatibilidade MHCII também foi investigada na epiderme. Resultados: A mediana das idades ao diagnóstico foi de 46 anos com 61% dos pacientes classificados como portadores de estágio avançado. A proporção entre homens e mulheres foi de 1,54 e a mediana de duração de doença antes do diagnóstico foi de três anos. Ao final de três anos de acompanhamento, 67% dos casos estavam vivos com a doença. O prurido foi relatado em 82% dos casos. Histologicamente, encontrou-se associação entre a presença de eosinófilos e de plasmócitos com fibroplasia do tecido conjuntivo. Observou-se diminuição da expressão do HLA-G no epitélio folicular nos grupos MFF e MFC em relação à pele normal. Observou-se aumento da expressão do MHCII no epitélio folicular na MFF em comparação à pele normal e na epiderme na MFC quando comparada à MFF. Conclusões: Dados clínicos da população estudada assemelharam-se aos dados da literatura como estágio avançado ao diagnóstico e prognóstico reservado. Cerca de metade dos casos de MFF foi positiva para o marcador citotóxico TIA-1. Demonstrou-se haver um provável colapso do imunoprivilégio folicular nos linfomas cutâneos com expressão diminuída de moléculas HLA-G em comparação à pele normal. O aumento da expressão do MHCII poderia relaciona-se com o foliculotropismo na MFF e com o epidermotropismo na MFC / Introduction: Folliculotropic mycosis fungoides (FMF) is a subtype of cutaneous T cells lymphoma affecting mainly the hair follicle and seems to have a less favorable prognosis. Clinical information on the population affected by cutaneous lymphomas in Brazil is scarce. The immune privilege (IP) phenomenon involves the ability of some body sites remaining protected from inflammatory reactions. It has been suggested that normal hair follicle represents an IP location. We hypothesized that a collapse of this phenomenon would occur in FMF, with changes in the expression of classical major histocompatibility molecules (MHC) and in the expression of nonclassical MHC molecules (HLA-G) with a role in folliculotropism mechanism. The objectives of this study were to describe the clinical and epidemiological profile of patients with MFF, describe the histology and immunophenotype of cases of MFF and investigate the expression of MHC molecules. Methods: The medical records of patients from the outpatient Cutaneous Lymphoma Clinic of the University of Sao Paulo Medical School (FMUSP) diagnosed with MFF were reviewed (n = 33). The histological material from skin biopsies of patients with MFF from the Cutaneous Lymphomas Clinic of FMUSP and Northwestern University was stained and evaluated by semi-quantitative scale. In hematoxylin-eosin staining the following parameters were evaluated: epidermal neoplastic infiltrate, dermal neoplastic infiltrate, acanthosis/spongiosis, follicular mucinosis, connective tissue fibroplasia, presence of eosinophils and plasma cells, cell size and degree of follicular damage. We analyzed the positivity of the neoplastic infiltrate for the following cellular markers: CD1a, CD56, TIA-1, and CD117. Finally, the expression of histocompatibility complex HLA-G and MHC II in the neoplastic infiltrate and the follicular epithelium was investigated in MFF group and compared to patients with classical mycosis fungoides (CMF) and to normal skin. MHCII expression in the epidermis was also investigated. Results: The median age at diagnosis was 46 years, with 61% classified as advanced stage disease. The ratio between men and women was 1.54, the median disease duration before diagnosis was three years. After a median time of follow-up of three years, 67% of the cases were alive with disease. Pruritus was reported in 82% of the cases. Histologically, an association between the presence of eosinophils and plasma cells with fibroplasia of collagen was found. There was a decrease of HLA-G expression in the follicular epithelium in MFF and CMF groups compared to normal skin. There was an increase of MHCII expression in the follicular epithelium in FMF group compared to normal skin. There was an increased MHCII expression in the epidermis in CMF compared to FMF. Conclusions: Clinical data from the studied population were similar to the previous literature in relation to advanced stage at diagnosis and prognosis. There was a relationship between the presence of eosinophils and plasma cells in neoplastic infiltrate and the connective tissue fibrosis. Near half of the cases of FMF was positive for the cytotoxic marker TIA-1. A possible hair follicle immune privilege collapse was suggested by a decreased expression of HLA-G molecules in FMF and CMF compared to normal skin. Increased MHCII expression appears to be involved in the folliculotropism of FMF and epidermotropism of CMF
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Avaliação da fotoestabilidade e penetração cutânea de fotoprotetores contendo associações de filtros solares, trans-resveratrol e beta-caroteno / Evaluation of photostability and cutaneous penetration of sunscreens containing combinations of UV-filters, trans-resveratrol and beta-carotene

Juliana Vescovi de Freitas 22 August 2013 (has links)
Em virtude da necessidade de proteger a pele contra as espécies reativas de oxigênio, geradas excessivamente após exposição ao raios UV, substâncias antioxidantes têm sido adicionadas aos fotoprotetores. Entretanto associações fotoinstáveis podem levar à formação de intermediários reativos, que são prejudiciais ao organismo, e à redução da atividade fotoprotetorados filtros solares e antioxidantes. Além disso, as características de penetração dos filtros solares e antioxidantes influenciam diretamente a segurança e a eficácia dos fotoprotetores. Dessa forma, o objetivo deste trabalho foi desenvolver e avaliar a fotoestabilidade e a penetração cutânea de formulações fotoprotetoras contendo diferentes associações de filtros solares acrescidas ou não de trans-resveratrol e beta-caroteno, por meio do uso de CLAE e espectrofotometria e de células de Franz, respectivamente. Para tal, foram desenvolvidas formulações contendo diferentes associações de filtros solares (associações 1, 2 e 3), que apresentavam em comum avobenzona, metoxicinamato de etil-hexila e octocrileno, acrescidas de trans-resveratrol e beta-caroteno, isoladamente ou em combinação. Para avaliar a fotoestabilidade, amostras das formulações foram aplicadas em lâminas de vidro e expostas à radiação UVA e, a seguir, submetidas a análises por CLAE, para determinar o teor dos filtros solares e antioxidantes em estudo, e por espectrofotometria, para determinação da razão UVA/UVB. Para avaliar a penetração cutânea, as formulações contendo a associação de filtros solares mais fotoestável foram aplicadas sobre a pele de orelha de porco, e foi realizada a quantificação das substâncias em estudo, presentes no estrato córneo (EC), na epiderme/derme (E+D) e na solução receptora, por CLAE. O estudo de fotoestabilidade por CLAE dos filtros solares e antioxidantes presentes nas formulações avaliadas mostrou que, apesar de terem apresentado boa fotoestabilidade, todas as substâncias foram fotoinstáveis, com exceção do bemotrizinol, octiltriazona e octocrileno. Além disso, foi observado que o uso dos antioxidantes em associação foi melhor do que utilizá-los separadamente em fotoprotetores. As análises espectrofotométricas mostraram que, após irradiação, houve redução significativa da razão UVA/UVB de todas as formulações e que as formulações contendo bemotrizinol (associação 2) e octiltriazona (associação 3) apresentaram, respectivamente, aumento e redução significativos da razão UVA/UVB, com relação às formulações que não apresentavam esses filtros. No estudo de penetração cutânea, foi observado que, após aplicação das formulações contendo bemotrizinol (associação 2), os filtros solares e antioxidantes avaliados penetraram a pele, mas não permearam até a solução receptora, ou seja, ficaram retidos no EC, majoritariamente, e na E+D. Além disso, foi observada redução significativa da retenção no EC dos filtros solares e antioxidantes avaliados na presença do beta-caroteno. Os resultados desse estudo contribuíram para mostrar os benefícios da utilização de uma combinação de antioxidantes em fotoprotetores, uma vez que a combinação do trans-resveratrol e do beta-caroteno, resultou em melhor fotoestabilidade das formulações e também apresentou vantagens no estudo de penetração cutânea, pois reduziu a penetração dos filtros solares. / Due to the need to protect the skin against reactive oxygen species, which are excessively generated after exposure to UV rays, antioxidants compounds have been added to sunscreens. However, photounstable combinations can lead to generation of reactive intermediates, that are harmful to the body, and decrease the photoprotective activity of UV-filters and antioxidants. Furthermore, the penetration characteristics of UV-filters and antioxidants influence directly sunscreens safety and efficacy. Thus, the aim of this study was to develop and to evaluate the photostability and cutaneous penetration of sunscreen formulations containing different combinations of UV-filters supplemented or not with trans-resveratrol and beta-carotene, by using HPLC and spectrophotometry and Franz cells, respectively. For this, formulations containing different UV-filters combinations (combinations 1, 2 and 3), which had in common avobenzone, ethyl-hexyl methoxycinnamate and octocrylene, supplemented with trans-resveratrol and beta-carotene, alone or in combination, were prepared. For photostability evaluation, samples of the formulations were spread onto glass plates, exposed to UVA radiation and then analyzed by HPLC to determine the concentration of UV-filters and antioxidants under study, and by spectrophotometry to determine the UVA/UVB ratio. To assess cutaneous penetration, formulations containing the most photostable combination of UV-filters were applied on pig ear skin, and the quantification of substances under study present into stratum corneum (SC), viable epidermis plus dermis (E+D) and receptor fluid was performed by HPLC. HPLC photostability study, which analyzed the UV-filters and antioxidants present in formulations, showed that all substances, despite having good photostability, were photounstable, except bemotrizinole, octyltriazone and octocrylene. Furthermore, it was observed that the use of antioxidants in combination was better than using them separately in sunscreens. The spectrophotometric analysis showed that after irradiation, all formulations had a significant decrease of UVA/UVB ratio, and that formulations containing bemotrizinole (combination 2) and octyltriazone (combination 3) presented, respectively, significant increase and decrease of the UVA/UVB ratio, in comparison with formulations that did not contained these UV-filters. In the cutaneous penetration study it was observed that after application of formulations containing bemotrizinole (combination 2), the UV-filters and antioxidants under study penetrated the skin, but did not reach the receptor fluid, which means that they were retained in SC, predominantly, and in E+D. Furthermore, a significant decrease on SC retention of UV-filters and antioxidants under study in the presence of beta-carotene was observed. The results of this study contributed to demonstrate the benefits of using a combination of antioxidants in sunscreens, since the combination of trans-resveratrol with beta-carotene, resulted in improved photostability of the formulations and also showed advantages in the skin penetration study, because it reduced UV-filters penetration.
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Vieillissement de nanoparticules de TiO2 en lotion solaire : évolution de leur impact sur des germes représentatifs du microbiote cutané / Aging of TiO2-nanoparticles in sunscreens : evolution of their impact on representative germs of the cutaneous microbiota

Rowenczyk, Laura 07 December 2016 (has links)
Les nanoparticules de dioxyde de titane (TiO2) sont largement utilisées dans les cosmétiques, notamment dans les lotions solaires, pour leurs propriétés optiques intéressantes. Cependant, le TiO2 étant très réactif et potentiellement nocif pour les cellules cutanées, celui-ci est recouvert d’une couche de passivation composée d’espèces chimiques inertes. D’autres traitements de surface peuvent par la suite être appliqués afin de faciliter leur dispersion dans les cosmétiques. Ainsi, les nanoparticules de TiO2 de grades cosmétiques ont des chimies de surface variées qui leur confèrent des propriétés physicochimiques propres. Cependant, le comportement de ces particules lors de leur utilisation en émulsion cosmétique est peu connu. Lors de ce travail de thèse, plusieurs systèmes nanoparticules/émulsion ont été étudiés au cours de leur vieillissement accéléré et suivant les conditions d’utilisation. Tout d’abord, l’impact de deux nanoparticules de traitements de surface différents a été testé sur les mécanismes de (dé)stabilisation des émulsions solaires. Puis, les nanoparticules en émulsion ont été caractérisées au cours du temps et ont fait apparaitre des modifications chimiques rapides au niveau de leur surface. Celles-ci affectent les propriétés physicochimiques des surfaces et ont été prises en compte lors du suivi de l’impact de ces nanoparticules sur les bactéries à travers des protocoles imitant les conditions réelles d’exposition. / Nanoparticles of titanium dioxide (TiO2) are currently used in cosmetics, especially in sunscreens, because of their interesting optical properties. However, the TiO2 is really reactive and could promote the formation of dangerous species for the cutaneous cells. For that reason, these particles are passivated by the application of inert surface treatments. Other coatings could be added in order to improve the dispersion of nanoparticles in the emulsion. Hence, the cosmetic grades of TiO2-nanoparticles have diverse physicochemical surface properties and their behavior in cosmetic use is uncertain. In this work, nanoparticles/emulsion systems were studied during their accelerated aging, mimicking use conditions. First, the impact of two nanoparticles with different surface treatments were tested on the (de)stabilization mechanisms in emulsions. Then, the nanoparticles were characterized within the emulsions and highlighted quick surface modifications. As these changed the physicochemical surface properties of the nanoparticles, they were taken into account during the evaluation of the NP impact on cutaneous bacteria.
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Caractérisation fonctionnelle des récepteurs NK à la surface des lymphocytes T CD4+ tumoraux et normaux

Remtoula, Natacha 01 December 2009 (has links)
Le syndrome de Sézary (SS) est un variant leucémique et érythrodermique de lymphomes T cutanés. Il est caractérisé par la présence d’une population clonale de LT CD4+, présentant un noyau cérébriforme atypique, dans la peau, les ganglions lymphatiques et le sang périphérique. Après un bilan clinique, le diagnostic de cette pathologie est confirmé par l’analyse immunohistochimique d'une biopsie cutanée. Néanmoins, la cytomorphologie des cellules de Sézary circulantes n’est pas uniquement associée au SS. Notre laboratoire a identifié CD158k comme marqueur membranaire spécifique des cellules de Sézary. Ce récepteur offre un intérêt dans le diagnostic du SS et dans le suivi de l’évolution de la pathologie. Ainsi, nos résultats montrent qu’un immuno-marquage CD3+ CD158k+, analysé en cytométrie en flux, est une technique spécifique et sensible de détection de la cellule de Sézary par rapport à la cytomorphologie. Alors que dans plus de 30% des cas le SS passe inaperçu durant l’examen cytomorphologique, une analyse en cytométrie en flux permet la mise en évidence de cellules tumorales résiduelles. La présence systématique de CD158k à la surface des cellules de Sézary nous a conduit à rechercher l’expression d’autres KIRs. Sur les lymphocytes tumoraux circulants d’un patient ainsi que sur la lignée cellulaire correspondante, l’expression des formes activatrices et inhibitrices des récepteurs CD158a/h et CD158b/j est détectée. A la différence des lymphocytes NK et T CD8+, le récepteur présentant une fonction inhibitrice (KIR-L) ne l’emporte pas sur celui ayant une fonction activatrice (KIR-S) dans la cellule de Sézary. En fait, les KIR-L, à l’exception de CD158k, sont trouvés non fonctionnels dans la cellule tumorale. Ainsi, l’engagement des formes activatrices CD158h ou CD158j permet une régulation positive de la voie de signalisation CD3-dépendante de JNK et de la prolifération tumorale. Une étude fonctionnelle de la population T CD4+ KIR+, équivalent normal de la cellule de Sézary, a aussi été réalisée. Nous avons mis en évidence une expression préférentielle de la forme activatrice ou inhibitrice des récepteurs KIR homologues, selon le donneur. D’autre part, les KIRs activateurs ou inhibiteurs, exprimés à la surface des LT CD4+, jouent un rôle de co-récepteur vis-à-vis du TCR. Ainsi, une régulation positive ou négative de la prolifération et de la voie de signalisation CD3-dépendante de ERK est observée en fonction du type de récepteur co-engagé. Il est bien établi que les KIR-S s’associent à la molécule adaptatrice KARAP/DAP12 pour la transduction d’un signal d’activation. Dans les cellules T CD4+ saines et tumorales, la protéine recrutée par ces récepteurs est encore non identifiée. Notre étude sur la population T CD4+ CD158j+ de sujets sains montre l’implication de la protéine HS1 dans la signalisation mise en place par le récepteur KIR activateur. La réalisation de ce travail a permis de mieux comprendre les mécanismes mis en place à partir des KIRs dans les cellules T CD4+. Ce travail ouvre de nouvelles perspectives concernant le rôle de ces récepteurs dans les mécanismes permettant l'expansion tumorale des cellules de Sézary / Sézary syndrome (SS) is a leukemic and erythrodermic variant of cutaneous T-cell lymphomas. It is characterized by the presence of a clonal CD4+ T lymphocyte population in the skin, lymphnodes and peripheral blood. After clinical assessment, diagnosis of this disease is confirmed by immunohistochemistry analysis of a skin biopsy. However, the cytomorphology of circulating Sézary cells is not just associated to SS. Our laboratory has identified CD158k as a phenotypic marker for Sézary cells. This receptor can be used in the diagnosis of the SS and in monitoring the evolution of the disease. Our results show that the CD3/CD158k immunostaining, analysed by flow cytométrie, is more specific and sensitive than cytomorphology to detect atypical circulating cells. While more than 30% of the SS is misdiagnosed by the cytomorphologic identification, flow cytometry analysis allows the detection of residual tumor cells. Given the systemic expression of CD158k on Sézary cells, we next investigated the expression of additional KIRs. On circulating malignant lymphocytes from one patient and the corresponding cell line, the expression of inhibitory and activating forms of CD158a/h and CD158b/j receptors was detected. In contrast to NK cells and CD8+ T lymphocytes, the inhibitory receptor signaling (KIR-L) does not outweigh the activating receptor signaling (KIR-S) in the Sézary cell. In fact, KIR-L, except CD158k, are found not functional in the tumor cell. Thus, CD158h or CD158j engagement results in an enhanced CD3-induced cell proliferation and JNK activation. A functional study of CD4+ KIR+ T lymphocyte population, the normal equivalent of Sézary cells, was then performed. We observed an exclusive expression of the activating or the inhibitory form of KIR receptors, depending on the donor. Activating or inhibitory KIRs, expressed on the CD4+ T cell surface, act as coreceptors. Thus, a positive or negative regulation of the CD3-induced cell proliferation and ERK activation is observed by triggering the KIR-S or -L respectively. It is well known that stimulatory KIR initiates intracellular signals through their association with the adaptor protein KARAP/DAP12. However, in normal and malignant CD4+ T cells the protein recruited by these receptors is still not identified. Our study on CD4+ CD158j+ T lymphocyte population from healthy individuals showed the involvement of HS1 protein as a potential adaptor molecule in the activating KIR signaling pathway. This work has provided insight into the mechanisms of KIRs signaling in CD4+ T cells and opens new perspectives on the role of these receptors in proliferation of Sézary cells
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Determinação da sensibilidade de isolados de Leishmania a antimoniato de meglumina, anfotericina B e tamoxifeno. / Determination of the sensitivity of Leishmania isolates to meglumine antimoniate, amphotericin B and tamoxifen.

Rogéria Cristina Zauli Nascimento 24 June 2009 (has links)
Nesse trabalho avaliamos a sensibilidade a drogas in vitro de alguns isolados obtidos de pacientes brasileiros com leishmaniose cutânea. O microteste de MTT modificado mostrou-se eficaz para avaliação da sensibilidade in vitro de promastigotas de Leishmania e macrófagos de medula como modelo de infecção por L. (V.) braziliensis. A atividade de tamoxifeno e anfotericina B foi similar entre os isolados de Leishmania avaliados. Foi observada uma variação maior da sensibilidade ao Glucantime®, sendo que os isolados de L. (V.) braziliensis apresentaram maior sensibilidade a essa droga. Não foi observada correlação da resposta clínica dos pacientes ao tratamento com a atividade in vitro. Avaliamos também a eficácia de tamoxifeno no tratamento de camundongos BALB/c infectados com L. (V.) braziliensis. Observamos que 20 ou 30 mg/kg/dia de tamoxifeno por 15 dias resultou em redução no tamanho das lesões e carga parasitária em comparação com animais controle.Um isolado apresentou morfologia flagelar distinta daquela observada em promastigotas típicos de Leishmania. / In this work we evaluated the in vitro sensitivity to drugs of some isolates from Brazilian patients with cutaneous leishmaniasis. The modified MTT microtest was effective for evaluation of in vitro sensitivity of Leishmania promastigotes and macrophages from bone marrow as a model of infection by L. (V.) braziliensis. The activity of tamoxifen and amphotericin B was similar among isolates of Leishmania evaluated. Sensitivity to Glucantime®, was more variable with isolates of L. (V.) braziliensis presenting higher sensitivity to the drug. There was no correlation between clinical response to treatment with in vitro activity. We have also evaluated the effectiveness of tamoxifen in the treatment of BALB/c mice infected with L. (V.) braziliensis and observed that 20 or 30 mg/kg/day of tamoxifen for 15 days resulted in reduction in the size of lesions and parasite load when compared with control animals. One of the isolates presented atypical flagellar morphology.
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Caractérisation génomique des anomalies de la pigmentation cutanée en mosaïque / Genomic characterization of mosaic cutaneous pigmentary disorders

Sorlin, Arthur 04 November 2019 (has links)
Introduction : Les dyschromies cutanées en mosaïque ont fait suspecter de longue date l’implication d’un mosaïcisme génétique sous-jacent. Ces évènements post-zygotiques sont cependant difficilement détectables par les techniques conventionnelles. Ainsi, les bases génétiques des dyschromies en mosaïque étaient restées mal connues. Matériel et méthodes : la cohorte M.U.S.T.A.R.D rassemble des échantillons d’ADN de biopsies cutanées de patients porteurs d’un mosaïcisme pigmentaire. Après une analyse phénotypique spécialisée, ces échantillons sont étudiés en séquençage à forte profondeur, d’exome (ES) en trio, ou ciblé. Les données sont analysées à l’aide d’un pipeline dédié, permettant la détection de variations ponctuelles en mosaïque (mSNV) mais également de diverses anomalies chromosomiques en mosaïque. Résultats : De 2013 à 2019, 101 patients ont été inclus. Un ES a été réalisé pour 56 patients, identifiant un mSNV chez 12 patients, dans 7 gènes dont 4 nouveaux (RHOA, DOCK1, GNA13, TFE3), et une anomalie chromosomique chez 17 patients. Une étude ciblée de ces gènes chez 40 autres patients était positive pour 17, soit un rendement diagnostique global à 55% (46/84). Conclusion : Ce travail illustre l’importance d’une approche bioinformatique polyvalente, combinée à une expertise clinique, pour la détermination des causes génétiques des dyschromies cutanées en mosaïque. Il a également mis en évidence le rôle de la voie de signalisation dépendant des Rho GTPases, faisant progresser notre compréhension de la physiopathologie des dyschromies en mosaïque, une étape nécessaire à l’amélioration de la prise en charge de ces patients porteurs de maladies rares et complexes. / Introduction: Mosaic cutaneous dyschromia is strongly evocative of an underlying genetic mosaicism. These post-zygotic events are challenging for conventional diagnostic tools. Thus, genetic basis of mosaic cutaneous dyschromia still remained poorly understood. Materials and Methods: The M.U.S.T.A.R.D. cohort gathers DNA from skin biopsies of patients with mosaic cutaneous dyschromia. After a specialised phenotype analysis, they are referred to either trio exome sequencing (ES) at 200X, or targeted ultra-deep sequencing (60,000X) of candidate genes. Data are analysed with a tailored pipeline, allowing detection of both low-rate nucleotidic variations or chromosomal events. Results: From 2013 to 2019, 101 patients were included. ES was performed for 56, with identification of mosaic SNV in 12 patients in 7 new genes, including 4 new genes (RHOA, DOCK1, GNA13, TFE3), and mosaic chromosomal anomalies in 17 patients. A targeted sequencing of these genes was performed for 40 more patients, with a confirmed mosaic SNV in 17, and a global diagnostic yield of 55% (46/84). Conclusion: This work highlights the importance of a versatile bioinformatic approach combined to a clinical expertise, to decipher the chromosomal and molecular aetiologies of developmental anomalies with mosaic cutaneous dyschromia. It also pinpoints the role of the Rho GTPase pathway, which will help enhancing our understanding of mosaic cutaneous dyschromia, and may ultimately result in better patients’ care.

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