Zhu Wen. / "May 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 217-249). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

O herpesvirus equino tipo 1 (EHV-1) é um importante patógeno que causa doença respiratória, abortamento e desordens neurológicas em equinos. O presente estudo foi realizado visando avaliar a resposta inflamatória causada pelo EHV-1 por meio da análise das manifestações clínicas, alterações histopatológicas e resposta imune do hospedeiro no sistema nervoso central (SNC). Camundongos das linhagens BALB/c (H2d), C57BL/6 (H2b) e C3H/HeJ (H2k) foram inoculados por via intranasal com as estirpes brasileiras A4/72 e A9/92 do EHV-1. Nesse estudo, associou-se a histopatologia, a resposta de citocinas pró-inflamatórias no SNC de camundongos das diferentes linhagens e o método de transcrição reversa seguida pela reação em cadeia da polimerase quantitativa em tempo real (RT-qPCR) para investigar a relação entre a infecção pelo EHV-1 e a resposta inflamatória com o desenvolvimento de lesões. As estirpes brasileiras A4/72 e A9/92 do EHV-1 causaram infecção aguda e letal nas diferentes linhagens de camundongos isogênicos. Os sinais clínicos e neurológicos, tais como perda de peso, pelos arrepiados, postura arqueada, apatia, dispneia, desidratação e sialorreia apareceram entre o 2º e 3º dia pós-infecção (dpi). Essas manifestações foram acompanhadas pelo aumento da sensibilidade a estímulos externos, convulsões, recumbência e morte. As alterações histopatológicas consistiram em necrose neuronal, edema, necrose de liquefação, leptomeningite neutrofílica, manguito perivascular, hemorragia focal, inflamação não supurativa, gliose multifocal e infiltração perivascular de células polimorfonucleares e mononucleares. As características e a extensão das lesões variaram entre as linhagens de camundongos. Animais inoculados com a estirpe A4/72 apresentaram lesões histopatológicas de maior grau de severidade quando comparados com aqueles inoculados com a estirpe A9/92. Observou-se aumento da concentração plasmática de TNF-α, IL-6, CCL2 e IFN-γ nos camundongos infectados pelo EHV-1 no 2º dpi. Detectou-se aumento da concentração plasmática e da expressão de mRNA para TNF-α, IL-6 e CCL2 no SNC dos camundongos infectados pelo EHV-1 no 3º dpi; entretanto, não houve aumento da concentração plasmática nem da expressão de mRNA para IFN-γ no 3º dpi. Evidenciou-se que a estirpe A4/72 do EHV-1 induz uma resposta imune sistêmica mais efetiva, enquanto que o vírus A9/92 culmina em uma resposta imunológica mais efetiva no SNC. Os camundongos com o fundo genético C57BL/6 e BALB/c mostraram níveis mais altos de expressão de mRNA para TNF-α, IL-6 e CCL2, quando comparados com os C3H/HeJ. A gravidade dos sinais clínicos observados em camundongos infectados pode ser correlacionada com o pico dessas citocinas pró-inflamatórias (TNF-α e IL-6) e da quimiocina CCL2, que são produzidas logo após a infecção viral por células residentes da glia e/ou infiltrativas no SNC. Esses achados indicam que as diferentes linhagens de camundongos isogênicos são susceptíveis à infecção por estirpes neuropatogênicas do EHV-1; as diferenças no padrão de alterações histopatológicas mostram que elas dependem do hospedeiro infectado, da estirpe viral e da resposta imunológica; e a supressão do interferon (IFN) tipo 1 sugere ser um mecanismo de escape do EHV-1 frente ao sistema imune. A baixa expressão de IL-6, TNF-α e da quimiocina CCL2 em camundongos C3H/HeJ se explica pela mutação no gene toll-like receptor 4 (TLR-4) existente nessa linhagem de camundongo. Adicionalmente, os camundongos C3H/HeJ apresentaram lesões histopatológicas mais severas no SNC quando comparados com BALB/c e C57BL/6. Sugere-se que o IFN tipo I e o gene TLR-4 apresentam importante papel na patogênese do EHV-1 bem como proteínas do agente viral responsáveis pela supressão do IFN e partículas virais que sejam reconhecidas pelo TLR-4 podem ser alvos para o desenvolvimento de novas abordagens para o tratamento da doença viral e para a eficiência de imunógenos / The equine herpesvirus type 1 (EHV-1) is an important pathogen that causes respiratory disease, abortion and neurological disorders in horses. This study was conducted to evaluate the inflammatory response caused by EHV-1 by the analysis of clinical manifestations, histopathological changes and the host immune response in the central nervous system (CNS). BALB/c (H2d), C57BL/6 (H2b) and C3H/HeJ (H2k) mice were inoculated intranasally with Brazilian EHV-1 strains A4/72 and A9/92. In this study, joined histopathology, the response of proinflammatory cytokines in the CNS of mice of different strains and reverse transcription method followed by quantitative polymerase chain reaction in real time (RT-qPCR) to investigate the relationship between infection by EHV-1 and inflammatory response in the development of lesions. Brazilian strains A4/72 and A9/92 EHV-1 caused acute lethal infection in different strains of inbred mice. Clinical and neurological signs such as weight loss, the bristly hair, hunched posture, apathy, dyspnoea, dehydration and salivary hypersecretion appeared between 2nd and 3rd day after infection (dpi). These events were accompanied by increase in the sensitivity to external stimuli, convulsions, recumbency and death. Histopathological changes were neuronal necrosis, edema, liquefaction necrosis, neutrophilic leptomeningitis, perivascular cuff, focal hemorrhage, non-suppurative inflammation, multifocal gliosis and perivascular infiltration of polymorphonuclear and mononuclear cells. The characteristics and the extent of the injuries varied between strains of mice. Animals inoculated with the A4/72 strain showed histopathological lesions of greater severity when compared with those inoculated with the A9/92 strain. There was an increase in plasma concentrations of TNF-α, IL-6, CCL2 and IFN-γ in mice infected by EHV-1 in 2nd dpi. Plasma concentrations and the expression of mRNA for TNF-α, IL-6 and CCL2 in the CNS of mice infected with EHV-1 at 3rd dpi were increased; however, there was no increase in plasma concentration or expression for the mRNA of IFN-γ at 3rd dpi. It was evident that the EHV-1 strain A4/72 induces a more effective systemic immune response, whereas the A9/92 virus culminates in a more effective immune response in the CNS. The C57BL/6 and BALB/c mice showed higher levels of mRNA expression for TNF-α, IL-6 and CCL2, compared to C3H/HeJ mice. The severity of clinical signs observed in infected mice can be correlated with the peak of these proinflammatory cytokines (TNF-α and IL-6) and CCL2 chemokine, which are then produced after viral infection by resident glial cells and/or infiltrative cells in the CNS. These findings indicate that different strains of inbred mice are susceptible to infection neuropathogenic EHV-1 strains; the differences in the pattern of pathological changes show that they depend on the infected host, the EHV-1 strain and the immune response; and the suppression of interferon (IFN) type I suggested to be an escape mechanism for the EHV-1 against the immune system. The low expression of IL-6, TNF-α and chemokine CCL2 in C3H/HeJ mice can be explained by a mutation in toll-like receptor 4 (TLR-4) gene existing in this mouse strain. Additionally, C3H/HeJ mice exhibited more severe histopathological lesions in the CNS as compared to BALB/c and C57BL/6. It is suggested that type I IFN and TLR-4 gene have important role in the pathogenesis of EHV-1 and viral agent proteins responsible for the suppression of IFN and the viral particles that are recognized by TLR-4 can be targets for the development of new approaches for the treatment of viral disease and the efficiency of immunogens

Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 139-154).

L’infection primaire au VZV et la réactivation du VZV latent sont fréquemment observées à la suite d’une GMO ou d’une GSCO, ce qui cause de sérieuses complications chez le patient. Pour prévenir ces infections, une prophylaxie antivirale est administrée systématiquement chez tous les greffés de MO ou de SCO, alors qu’il n’existe aucun consensus sur la durée optimale d’une telle prophylaxie. Pour résoudre ce problème, notre objectif est de développer et valider une méthode ELISpot-VZV-IFN- qui permettra de suivre la reconstitution de l’immunité à médiation cellulaire anti-VZV chez les receveurs de GMO ou de GSCO et ainsi déterminer le moment opportun pour réduire ou interrompe la prophylaxie chez les receveurs de greffes de CSH. Dans un premier temps, des valeurs-seuil de la réponse à médiation cellulaire anti-VZV chez la population pédiatrique saine ont dû être générées. À la lumière de nos résultats, un enfant avec un résultat ELISpot-VZV-IFN- > 190.0 SFU/106 PBMC devrait être protégé contre une possible infection à VZV. Pour valider cette étude, une étude prospective de la reconstitution immunitaire anti-VZV a été effectuée chez 9 enfants greffés de MO ou de SCO. Nos résultats préliminaires ont montré qu’il n’y avait eu aucune reconstitution significative de l’immunité à médiation cellulaire anti-VZV dans les 18 premiers mois post-transplantation chez 8 de ces 9 enfants. Les résultats de ces expériences vont fournir d’importantes informations quant à la reconstitution de l’immunité anti-VZV à la suite d’une GMO ou d’une GSCO et pourraient permettre l’amélioration des soins apportés aux receveurs de GMO ou de GSCO. / Primary infection with VZV and reactivation of latent VZV are commonly observed following BMT and UCBT, leading to serious complications in patients. As a result, antiviral prophylaxis is systematically administered to BMT and UCBT recipients, yet there is no consensus that defines its optimal duration. To resolve this problem, our objective was to develop and validate a VZV-IFN--ELISpot with which reconstitution of VZV immunity can be followed in BMT and UCBT recipients, providing clinicians a practical tool to gauge the need for and adjust antiviral prophylaxis in individual HSCT recipients. First of all, threshold values for anti-VZV immunity in healthy pediatric subjects were generated. Based on our results, a child exhibiting > 190.0 VZV-specific SFU /106 PBMC should be protected against a possible VZV infection. To validate these results, a prospective study on the recovery of VZV-specific T cell immunity was performed on 9 children following BMT or UCBT. Preliminary results demonstrated that there was no significant recovery of VZV-specific T cell immunity in the first 18 months post-transplantation in 8 of 9 cases. Results of these experiments will yield important new information regarding reconstitution of anti-VZV immunity following BMT and UCBT and could lead to improvements in clinical management of BMT and UCBT recipients.

Le virus de l’Herpès simplex de type 1 (HSV-1) est le pathogène humain responsable des lésions herpétiques labiales, plus communément appelé « feux sauvages ». Annuellement, il est responsable de plusieurs cas d’encéphalites et d’infections de l’appareil visuel qui sont la principale cause de cécité en Amérique du Nord. Bien qu’il existe quelques traitements antiviraux, aucun vaccin ou médicament ne permet de prévenir ou de guérir les infections causées par ce virus. Aujourd’hui, les infections produites par l’HSV-1 sont présentes partout sur la planète. Récemment, une étude en protéomique effectuée sur les virus matures extracellulaires a permis d’identifier la présence d’ubiquitines libres et d’enzymes reliées à la machinerie d’ubiquitination dans le virus. De plus, le virus exploite cette machinerie au cours de l’infection. Il est connu que certaines protéines virales sont ubiquitinées durant une infection et que le virus imite même certaines enzymes d’ubiquitination. Nous avons donc entrepris des recherches afin d’identifier des protéines virales ubiquitinées qui pourraient être présentes dans les virus matures ainsi que leurs rôles potentiels. La protéine majeure de la capside, VP5, un constituant très important du virus, a été identifiée. Nos recherches nous ont permis de caractériser le type d’ubiquitination, une monoubiquitination sur les lysines K810 et/ou K1275 de VP5. Le rôle que pourrait jouer l’ubiquitination de VP5 dans le cycle de réplication virale et dans les virus matures n’est toutefois pas encore connu. / Herpes simplex virus type 1 (HSV-1) is the human pathogen responsible for herpetic lesion such as cold sores. On a yearly basis, it is responsible for many cases of encephalitis and infections of the eye that are the most common cause of blindness in North America. Antiviral treatments exist, but no vaccines or drugs are able to prevent or cure the diseases caused by this virus. Today, infections caused by HSV-1 are present all around the world. Recently a proteomics approach was used to study mature extracellular viruses. This study highlighted the presence in the virus of free ubiquitin and ubiquitin related enzymes. Furthermore, the virus exploits this machinery during the course of infection. Also, it is known that certain virally encoded proteins are ubiquitinated and that the virus mimics some ubiquitin related enzymes. Our researches focused on identifying ubiquitinated viral proteins that could be present in mature extracellular viruses and their potential roles. The major capsid protein, VP5, an important virus component, was identified. We characterised the type of ubiquitination, a monoubiquitination of lysine K810 and/or K1275 of VP5. The role that could play the ubiquitination of VP5 in the viral cell cycle and in mature virions has yet to be identified.

Les virus exploitent la machinerie cellulaire de l’hôte de façon très variée et plusieurs types vont même jusqu’à incorporer certaines protéines cellulaires. Nous avons récemment effectué la première analyse protéomique du virion mature de l’Herpès simplex de type 1 (HSV-1), ce qui nous a permis de déterminer que jusqu’à 49 protéines cellulaires différentes se retrouvaient dans ce virus (Loret, S. et al. (2008). "Comprehensive characterization of extracellular herpes simplex virus type 1 virions." J Virol 82(17): 8605-18.). Afin de déterminer leur importance dans le cycle de réplication d’HSV-1, nous avons mis au point un système de criblage nous permettant de quantifier le virus produit et relâché dans le milieu extracellulaire en utilisant un virus marqué à la GFP ainsi que des petits ARN interférents (pARNi) ciblant spécifiquement ces protéines cellulaires. Cette approche nous a permis de démontrer que 17 des protéines identifiées précédemment jouaient un rôle critique dans la réplication d’HSV-1, suggérant ainsi que leur incorporation dans le virus n’est pas aléatoire. Nous avons ensuite examiné le rôle d’une de ces protéines, DDX3X (DEAD (Asp-Glu-Ala-Asp) box polypeptide 3, X-linked), une protéine multifonctionnelle connue pour son implication dans les cycles de réplication de plusieurs virus humains. À l’aide de pARNi ainsi que de différentes lignées cellulaires, dont une lignée DDX3X thermosensible, nous avons démontré que l’inhibition de DDX3X résultait en une diminution du nombre de capsides intracellulaires et induisait une importante diminution de l’expression des gènes viraux. Nous avons aussi démontré que la fraction de DDX3X incorporée dans le virion contribuait activement au cycle infectieux d’HSV-1. Ces résultats confirment l’intérêt de notre approche afin d’étudier les interactions hôte-pathogène en plus de démontrer la contribution des protéines cellulaires incorporées à HSV-1 dans l’infection virale. / Viruses exploit the cellular machineries in many ways and several viruses specifically incorporate host proteins. To understand their biological relevance, we recently performed the first comprehensive characterization of the mature herpes simplex virus type 1 (HSV-1) in which up to 49 distinct cellular proteins were identified by mass spectrometry. In the present study, we sought to identify which of these cellular factors are critical for the HSV-1 life cycle. To this end, we performed a functional screen using small interfering RNA (siRNA) and a GFP-tagged virus, which indicated that at least 17 of the virion-incorporated host proteins alter HSV-1 proliferation in cell culture. Interestingly, these include several Rab GTPases and other intracellular transport components as well as proteins involved in signal transduction, gene regulation and immunity. Among them, the DEAD (Asp-Glu-Ala-Asp) box polypeptide 3, X-linked protein (DDX3X) is a multifunctional molecule previously linked to several other viruses. Its relevance for HSV-1 was further confirmed with different siRNA reagents and cell lines, including a DDX3X thermosensitive cell line. We found that DDX3X inactivation reduced intracellular capsid abundance via a strong inhibition of viral gene expression. We also report evidence that the pool of DDX3X present in the mature virions actively contributes to HSV-1 life cycle. Altogether, this highlights a powerful and biologically relevant approach to characterize host-pathogen interactions and points to the important contribution host proteins within mature viral particles.

Herpesviruses have co-speciated with several vertebrate and invertebrate animals throughout the history of evolution. In the immunocompetent human host, primary infection is usually benign, whereafter the virus is brought into life-long latency. Viral reactivation can however cause severe disease in immunocompromised, and rarely also in immunocompetent, patients. The overall aim of this thesis was to study the immunologic effects of cytomegalovirus (CMV) and herpes simplex type 1 (HSV-1) infection in neurocognitive disorders. CMV is known to promote T-cell differentiation towards a more effector-oriented phenotype, similar to what is seen in the elderly. We have addressed the frequency of CMV-specific CD8+ T-cells in Alzheimer's disease (AD). Furthermore, we have investigated whether AD patients present with a different CMV-specific immune profile, overall CD8 phenotype or inflammatory cytokine response to anti-CD3/CD28 beads, CMV pp65 and amyloid beta. Subjects with AD presented with a lower proportion of CMV-specific CD8+ T-cells compared to non-demented (ND) controls, but no differences in overall CD8 differentiation were seen. Overall, AD subjects presented with a more pro-inflammatory peripheral blood mononuclear cell (PBMC) phenotype. When PBMCs were challenged with CD3/CD28-stimulation, CMV seropositive AD subjects presented with more IFN-γ release than both CMV seronegative AD subjects and CMV seropositive ND controls. For effective screening of humoral herpesvirus immunity, both in research and in clinical practice, efficient immunoassays are needed. We have addressed the methodology of multiplex herpesvirus immunoassays and related bioinformatics and investigated antibody levels in AD patients and ND controls. Subjects with AD presented with lower levels of human herpesvirus 6 (HHV-6) IgG. However, there was no difference in HHV-6 DNA levels in PBMCs between the groups. Herpes simplex encephalitis (HSE) is a devastating disease, where antiviral treatment has greatly decreased mortality but not eliminated the associated long-term neurocognitive morbidity. We have investigated the correlation between N-Methyl-D-Aspartate Receptor (NMDAR) autoimmunity and recovery of neurocognitive functions after HSE. Approximately one quarter of all HSE cases developed NMDAR autoantibodies within 3 months after onset of disease. Antibody development was associated with an impaired neurocognitive recovery during the two year follow-up and could become an important therapy guiding factor in the future.

La dérégulation de l’expression des microARN peut induire des cancers. De plus, ils jouent un rôle crucial dans la pathogénèse et la survie des virus. L’herpès virus humain de type 8 (HHV-8 ou KSHV) est l’agent étiologique du sarcome de Kaposi et est impliqué dans la génération de lymphomes agressifs de type B. De manière intéressante, le génome ce virus code 12 pré-miARN localisés dans la région de latence et exprimés sur un même pri-miARN. Les miARN du KSHV sont importants pour le maintien de la latence, l’inhibition de l’apoptose ou encore la régulation du cycle cellulaire de l’hôte. Nous nous intéressons à leur expression et leur régulation durant l’infection virale. Nous avons résolu la structure secondaire de l’ARN codant ces miARN afin d’identifier les critères structuraux responsables de leur accumulation différentielle. Nous avons initié une analyse cinétique de la première étape de maturation et enfin nous essayons d’identifier des co-facteurs modulant leur expression. / It is now well known that modulation of microRNAs expression is linked to the development of cancers. Moreover, they play a crucial role in the pathogenesis and the survival of some viruses. Kaposi’s sarcoma associated herpes virus (KSHV) is the etiologic agent of Kaposi’s sarcoma and is involved in human aggressive B lymphomas generation. Its genome encodes 12 precursor miRNAs that are clustered in a latency region and expressed on a single long primary transcript. KSHV miRNAs are important to maintain the virus latency and to regulate or inhibit the host cell cycle or apoptosis, respectively. Therefore, understanding the regulation of KSHV miRNA accumulation is of prime importance. In this respect, we resolved the secondary structure of them iRNA cluster to identify structural criteria responsible of their differential accumulation. In addition, we started to analyse the mechanism of their maturation by kinetics studies. Finally we tried to identify some cofactors of miRNA expression.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The bovine mammillits caused by bovine herpesvirus type 2 (BoHV-2) is an important disease of dairy cattle yet very little is known about its pathogenesis. This study aimed at reproducting and characterizing the clinical-pathological aspects of bovine herpesvirus mammillits in experimentally infected sheep. In the first experiment, ten lambs were inoculated in the nasal mucosa and the virological, clinical and serological aspects of acute infection were monitorated. Virus sheeding was detected in nasal secretions of 7 lambs between days 2 and 8 post inoculation (pi) and lasted from one to three days. A serous nasal discharge, changing to mucous and mucopurulent, was observed in all animals between days 2 and 5 pi. Seven lambs developed vesicles, pustules and erosions in the nasal mucosa between days 4 and 8 pi. All inoculated animals seroconverted to BoHV-2. Dexamethasone administration at day 40 pi was not followed by virus shedding, clinical recrudescence or seroconversion. In the second experiment, eight milking ewes were inoculated in the skin of the teats and udder, and monitorated thereafter regarding to viral replication, clinical signs and histological changes. Infectious virus was isolated from lesion swabs of one ewe on days 7 and 8 pi. Five animals developed lesions in inoculation sites between days 4 and 6 pi. The clinical-pathological aspects of the lesions were similar to those of natural infections and were characterizated by erythema, edema, papules, vesicles, exsudation and scabs. By histological examination, the lesions displayed cellular edema and linfoplasmocitic multifocal infiltrate surrounding blood vessels in the dermis. Moreover, eosinophilic intranuclear inclusion bodies were observed in inflamatory cells and syncitia. Virus particles resembling herpesvirus were observed by eletronic transmission microscopy. These results indicate that sheep are susceptible to BoHV-2 infection, and can develop clinical signs similar to those observed in cattle in natural outbreaks of herpes mammillitis. Thus, this animal species may be used as a model to study pathogenesis, vaccine development and antiviral drugs. / A mamilite causada pelo herpesvírus bovino tipo 2 (BoHV-2) é uma importante enfermidade de gado leiteiro, porém pouco se sabe sobre a sua patogenia. O presente trabalho teve como objetivos reproduzir e caracterizar em ovinos as manifestações clínico-patológicas associadas com a infecção natural de bovinos pelo BoHV-2. Em um primeiro experimento, dez cordeiros foram inoculados na mucosa nasal e a infecção aguda foi monitorada nos aspectos clínicos, virológicos e sorológicos. Excreção viral em secreções nasais foi detectada em 7/10 animais entre os dias 2 e 8 pós-inoculação (pi), com duração que variou entre um e três dias. Todos animais apresentaram secreção nasal serosa, passando a mucosa e mucopurulenta, entre os dias 2 e 5 pi, e sete deles apresentaram também hiperemia e o desenvolvimento de vesículas, pústulas e erosões na mucosa nasal entre os dias 4 e 8 pi. Todos os animais soroconverteram ao BoHV-2. A administração de dexametasona aos 40 dias pi não foi seguida de excreção viral, soroconversão ou recrudescência clínica. Em um segundo experimento, oito ovelhas lactantes foram inoculadas na pele das tetas e do úbere, seguida da caracterização virológica, clínica e histopatológica da infecção aguda. O vírus foi isolado a partir de suabes coletados das lesões de uma ovelha nos dias 7 e 8 pi. Cinco (5/8) animais desenvolveram lesões nos locais de inoculação entre os dias 4 e 6 pi. As lesões apresentaram características clínicopatológicas semelhantes às observadas em infecções naturais, e se caracterizaram por hiperemia, edema, pápula, vesículas, exsudação e formação de crostas. Histologicamente, as lesões se caracterizaram por edema intracelular, presença de um infiltrado linfoplasmocitário multifocal e predominantemente perivascular na derme, além de corpúsculos de inclusão eosinofílicos intranucleares em células inflamatórias e células sinciciais. Partículas víricas com morfologia típica de herpesvírus foram observadas sob microscopia eletrônica de transmissão. Esses resultados indicam que ovinos são susceptíveis à infecção pelo BoHV-2 e desenvolvem lesões características de mamilite herpética quando inoculados experimentalmente, podendo ser utilizados para estudos de patogenia, desenvolvimento de vacinas e pesquisas de drogas antivirais.

Le Ketosis-Prone Diabetes (KPD) est un phénotype de diabète intermédiaire entre le diabète de type 1 et le diabète de type 2, fréquemment rencontré chez le sujet d’origine noire africaine. Cette forme de diabète suscite un intérêt certain de par son évolution clinique marquée notamment par la restauration de l’insulinosécrétion initialement altérée. Sobngwi et coll. en 2008 ont établi une association entre le virus HHV8 et le KPD chez des sujets Africains vivant en France. Nulle part ailleurs l’étude n’a été reproduite. L’objectif de cette thèse était de rechercher la potentielle association entre l’infection à HHV8 et le KPD ; puis d’évaluer l’impact de l’infection à HHV8 sur le profil inflammatoire des phénotypes du diabète de type 2. L’étude s’appuie sur une population de patients Africains vivant en Afrique admis consécutivement pour une décompensation hyperglycémique (glycémie à jeun≥2,5g/l) au Centre National d’Obésité de l’Hôpital Central de Yaoundé. Plus spécifiquement, il était question de :• étudier la fréquence du diabète non auto-immun à tendance cétosique (KPD); • étudier l’association entre le virus HHV8 et le KPD;• rechercher si l’infection à HHV8 est associée à un profil inflammatoire pouvant participer aux phénotypes de diabète. Etait inclus dans l’étude tout patient diabétique âgé de plus de 18 ans présentant un diabète aigu avec syndrome cardinal et cétonurie (KPD1), ceux ayant présenté un diabète inaugural aigu avec syndrome cardinal et cétonurie et en rémission depuis plus de trois mois et sans cétonurie à l’inclusion (KPD2), et ceux présentant un diabète de type 2 connu sans cétonurie (DT2). Etait exclu de l’étude tout patient présentant des stigmates d’auto-immunité du diabète de type 1 A, un diabète « MODY », une endocrinopathie, une maladie du pancréas, ou un diabète de type auto-immun. Chez l’ensemble des participants admis, nous avons collecté les données cliniques (le poids, la taille, l’IMC, le rapport tour de taille sur tour de hanche, la pression artérielle, et le pourcentage de graisse) et des prélèvements à jeun ont été effectués (sérum et cellules mononuclées du sang périphérique) pour les analyses biologiques : la glycémie par glucose oxydase, l’HbA1c par HPLC, les paramètres du profil lipidique par des methodes enzymatiques, les concentrations d’insuline et de peptide-C par électrochimiluminescence, les anticorps anti-HHV8 par immunofluorescence, l’ADN viral HHV8 par PCR en temps réel, et les marqueurs de l’inflammation par le Luminex. Les indices HOMA-β et HOMA-IR ont été utilisés pour évaluer l’insulinosécrétion et la sensibilité à l’insuline respectivement. Les marqueurs sérologiques de l’inflammation recherchés étaient : TNF-α, MCP-1, IL-8, MIP-1β, VEGF et MIP-1α... / Ketosis-Prone Diabetes (KPD) is a diabetes phenotype intermediate between type 1 and type 2 diabetes, frequently encountered in populations of African origin. This form of diabetes arouses some interest because of its clinical course marked in particular by restoring the initial impaired insulin secretion. Sobngwi et al. in 2008 established an association between HHV-8 virus and KPD in African population living in France. Nowhere else has the study been replicated. The objective of this thesis was to investigate the potential association between HHV-8 infection and KPD; then evaluate the impact of HHV-8 infection on the inflammatory profile of type 2 diabetes phenotypes. The study is based on African patients living in Africa consecutively admitted for hyperglycemic decompensation (Fasting blood glucose≥2,5g/l) at the National Obesity Centre of the Yaounde Central Hospital. More specifically, the issue was:• study the frequency of non-immune ketosis-prone diabetes (KPD);• investigate the association between HHV8 and KPD;• investigate whether HHV-8 infection is associated with an inflammatory profile that may participate in diabetes phenotypes.Was included in this study all diabetic patients old more than 18 years with acute diabetes with syndrome cardinal and ketonuria (KPD1), those who presented with an acute inaugural cardinal syndrome and diabetes ketonuria and in remission for more than three months and without ketonuria at baseline (KPD2), and those with type 2 diabetes experienced without ketonuria (T2D). Was excluded from the study all patient with stigmata of autoimmunity of type 1 A diabetes, diabetes "MODY", endocrinopathy, pancreatic disease or an autoimmune diabetes.Among all participants admitted, we collected clinical data (weight, height, BMI, waist to hip ratio, blood pressure, and the percentage of fat) and levies fasting were made (serum and peripheral blood mononuclear cells) for biological testing: glyceamia by glucose oxidase, HbA1c by HPLC, lipid profile by enzymatic methods, the insulin and C-peptide concentrations by electrochemiluminescence, anti-HHV8 antibodies by immunofluorescence, HHV8 viral DNA by real-time PCR, and markers of inflammation by Luminex. HOMA-β and HOMA-IR indices were used to assess insulinsecretion and insulinsensitivity respectively. Serological markers of inflammation investigated were : TNF-α, MCP-1, IL-8, MIP-1β, MIP-1α and VEGF...