Dissertationen zum Thema „Kaposi's disease“

Thesis (Ph. D.)--University of Sydney, 2004.<br>Title from title screen (viewed 5 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Medicine. Includes list of published articles and presentations. Includes bibliographical references. Also available in print form.

HHV-8, the aetiological agent of Kaposi’s sarcoma (KS), multicentric Castleman’s disease (MCD) and primary effusion lymphoma (PEL) has been characterised in several parts of the world but largely overlooked in Australia, perhaps because highly active antiretroviral therapy (HAART) has drastically reduced the incidence of HHV-8-associated diseases in the most at-risk population, namely those with HIV disease. Previously, Australian researchers have looked briefly at the sexual behaviours associated with risk of transmission of HHV-8, at molecular methods for detecting the presence of this virus, and have genotyped just eight clinical isolates. Now, the re-emergence of HHV-8 disease associated with increased lifespan in HIV-positive individuals has created a need to better understand the biological importance of this virus, including in Australia and in the developing world. While report of KS and HHV-8 have been previously published from Australia, this project establishes the first research group devoted to the understanding of HHV-8 from an Australian perspective, develops validated quantitative molecular detection methods for HHV-8 in blood and oral fluids, and then characterises the viruses detected via phylogenetic analyses.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Dentistry and Oral Health<br>Griffith Health<br>Full Text

Kaposi's sarcoma-associated herpesvirus (KSHV), a gamma-herpesvirus with a particularly high seroprevalence in Sub-Saharan Africa (SSA), is the etiological agent of the endothelial tumour Kaposi's sarcoma (KS), the most common acquired immunodeficiency syndrome (AIDS)-related malignancy worldwide and particularly in SSA. It also causes primary effusion lymphoma (PEL), multicentric Castleman disease (MCD) and KSHV inflammatory cytokine syndrome (KICS). AIDS-related deaths have declined, due to global scale-up of antiretroviral therapy (ART). However, the vast majority of these occurred in SSA, where tuberculosis (TB) is the leading cause of mortality among human immunodeficiency virus (HIV)-infected individuals, accounting for a third of all AIDS-related deaths. The exceptionally high burden of suspected TB in SSA causes misdiagnosis or delayed diagnosis of diseases mimicking TB, such as several pathologies associated with KSHV. KSHV infection is essential but insufficient for the development of KS and other KSHV-associated pathologies; precipitating factors, such as HIV-related immune suppression and potentially genetic predisposition, are required. The erythropoietin-producing hepatocellular carcinoma (Eph) receptor A2 protein (EPHA2) tyrosine kinase receptor is a promising candidate for studies on genetic variants as it potentially acts on two levels: susceptibility to KSHV infection (being one of the key receptors utilised by KSHV for cell entry and intracellular trafficking) and susceptibility to KS development (being implicated in oncogenesis). Despite the high seroprevalence in SSA, the contribution of dysregulated KSHV lytic replication or host KSHV receptor variations to disease outcome in HIV-infected patients is unknown. We hypothesised that KSHV lytic reactivation plays yet unrecognised roles for morbidity and mortality in high HIV settings and to this end, we conducted a cohort study of 682 HIV-positive critically ill patients admitted to Khayelitsha Day Hospital, South Africa, investigated for TB, and followed for 12-weeks to ascertain vital status. We demonstrated that elevated blood KSHV viral load (VL) was a strong predictor of death in hospitalised HIV-infected patients without microbiologically proven TB. Further, we identified and validated variants in the EPHA2 protein tyrosine kinase and sterile alpha motif domains that were significantly associated with susceptibility to infection, KS development and/or KSHV VL in 300 South African HIV-infected patients, by aggregate by-gene analysis. In order to elucidate the functional significance of the identified EPHA2 missense mutations, we knocked out endogenous EPHA2 by CRISPR/Cas9 in the human endothelial cell line, HuARLT2, and reintroduced the wild type and mutant EPHA2 open reading frames by lentiviral transduction. These engineered cells were assessed for baseline EPHA2 phosphorylation levels and susceptibility to KSHV infection utilising recombinant KSHV in binding, internalisation and infection assays. We found that the EPHA2 mutant c.2254T>C (p.Leu700Pro) in the tyrosine kinase domain, associated with KS in our patient cohort, was deficient in tyrosine phosphorylation and less permissive to rKSHV infection when introduced as a single mutation or as a double mutant together with c.2257A>C (p.Asp701Ala) which was found to be in linkage disequilibrium with it. Another tyrosine kinase domain variant, c.2688G>S (p.Ala845Pro), found to be overrepresented among KS patients, had enhanced baseline tyrosine phosphorylation levels. These findings validated the patient-derived data on the molecular level by assigning functional consequences to some mutants which might have implications for the development of future biomarkers predicting KS susceptibility in high-risk populations. In summary, this novel research contributes to the understanding of KSHV-associated pathology and disease outcome. It identified KSHV VL as a potential biomarker to predict KSHV-associated diseases and mortality and assessed the contribution of KSHV entry receptor EPHA2 variations to KSHV-associated pathologies, with potential clinical implications, by facilitating the development of novel diagnostic and surveillance tools.

A infecção pelo herpesvírus humano tipo 8 (HHV-8) tem sido associada ao sarcoma de Kaposi (SK) iatrogênico, que acomete pacientes imunossuprimidos e/ou transplantados renais. Em populações consideradas saudáveis, a soroprevalência para o HHV-8 varia de 1% a 8%. O presente trabalho buscou: determinar a prevalência e os títulos de anticorpos anti-HHV-8 em pacientes com insuficiência renal crônica (IRC), submetidos ou não à terapia renal substitutiva (TRS) do Hospital do Rim e Hipertensão e Casa da Diálise da UNIFESP e da Santa Casa de Misericórdia de São Paulo e, comparar os resultados obtidos com outras populações da mesma região geográfica, porém de outras categorias de risco para adquirir doenças infecciosas. Soros de 805 pacientes: 295 em hemodiálise, 54 em diálise peritoneal e 456 em acompanhamento ambulatorial, sem TRS, foram testados quanto à presença de anticorpos anti-HHV-8, de fase latente e lítica da replicação viral, por meio de técnicas de imunofluorescência indireta (IFI) LANA e Lítico, padronizadas na Seção de Imunologia do Instituto Adolfo Lutz. Os resultados obtidos foram analisados em relação a dados clínicos, epidemiológicos e laboratoriais usando o teste do qui-quadrado ou exato de Fisher para as variáveis categóricas e os testes de Mann Whitney ou Kruskal Wallis para as variáveis contínuas. Foi encontrada soropositividade ao HHV-8 em 18,0% dos pacientes com IRC, dos quais 18,3% nos pacientes em TRS e 17,7% nos pacientes sem TRS, não havendo diferença significante entre os grupos. As variáveis que estiveram relacionadas à sorologia positiva ao HHV-8 foram: transplante prévio (p<0,001) e doenças sexualmente transmissíveis (p=0,003), com destaque para a sífilis (p=0,021). As demais variáveis não mostraram associação estatística embora tenha havido maior número de amostras HHV-8 soropositivas com o avançar da idade. Em relação ao tipo e ao título de anticorpos detectados, houve mais amostras com sorologia positiva para anticorpos Lítico e maiores títulos de anticorpos LANA. A comparação dos resultados dos pacientes com IRC e outras populações de São Paulo revelou taxa semelhante de prevalência de anticorpos anti-HHV-8 na população com HIV/Aids (20,4%), considerada de alto risco para esta infecção viral. Por outro lado, a prevalência detectada na população com IRC (18,0%) foi inferior às obtidas em pacientes com SK epidêmico (89,3%), SK clássico (100,0%) e SK endêmico (87,5%), e superior a outras populações sem SK: pacientes com deficiência mental e/ou física (1,6%) e profissionais da área da saúde (1,1%). Em todos os grupos analisados houve maior número de amostras com sorologia positiva para HHV-8 de fase lítica, e maiores títulos de anticorpos LANA, exceção feita aos profissionais da área da saúde. Maiores títulos de anticorpos LANA foram detectados nos pacientes com SK. Não foram encontradas outras associações significantes. Os resultados obtidos permitem concluir que os pacientes com IRC têm alta prevalência de anticorpos anti-HHV-8, comparável aos indivíduos com HIV/Aids dessa região geográfica. Ainda, sugerem que se devam acompanhar os pacientes HHV-8 soropositivos com vistas a monitorar os títulos de anticorpos LANA e verificar se estes têm valor prognóstico. Caso isto venha a ser confirmado, sugere-se a introdução da sorologia para o HHV-8 na bateria de exames do pré-transplante renal.<br>Human herpesvirus 8 (HHV-8) infection is frequently associated with Kaposi\'s sarcoma (KS) in immunodeficient and renal transplanted patients. The HHV-8 seroprevalence in healthy populations varies from 1% to 8%. The present study aimed to determine the HHV-8 seroprevalence and antibodies titers in chronic kidney disease (CKD) patients with or without substitutive kidney therapy (SKT) attended at Hospital do Rim e Hipertensão and Casa da Diálise of UNIFESP, and at Santa Casa de Misericórdia de São Paulo. Secondarly, to compare the serological results with those obtained from populations of the same geographic region, presenting other risk factors for acquiring infectious diseases. Serum samples were collected from 805 CKD patients: 295 under hemodialysis, 54 under peritoneal dialysis, and 456 in ambulatorial assistance without SKT. Latent and Lytic HHV-8 antibodies were searched using indirect immunofluorescence assays that were standardized at Immunology Department of Instituto Adolfo Lutz. Chi-Square test and/or Fisher\'s exact test were performed for comparing categorical variables including epidemiological, clinical and laboratorial data, and HHV-8 serum status. Continuos variables associated with HHV-8 antibodies titers were compared using Mann Whitney or Kruskal Wallis tests. An overall HHV-8-seropositivity of 18.0% was detected in CKD patients: 18.3% in patients under SKT and 17.7% in patients without SKT. Since no difference was detected in HHV-8-seropositivity among patients, they were considered as a unique group for subsequent analysis. A strong association between HHV-8-seropositivity and previous transplant was detected (p<0.001), along with an association with others sexually transmitted diseases (p=0.003), with emphasis for syphilis (p=0.021). In addition, no other data was associated with HHV-8-seropositivity, although higher proportions of HHV-8-seropositivity were detected in samples from elderly persons. In addition, more HHV-8 Lytic antibodies positive samples, and higher titers of LANA antibodies were detected. HHV-8 seroprevalence obtained from CKD patients was similar to the HHV-8 prevalence detected among HIV/Aids patients (20.4%), who were considered a high-risk group for this viral infection. On the other hand, the HHV-8 seroprevalence of CKD patients (18.0%) was lower than the prevalence of patients with epidemic KS (89.3%), classic KS (100.0%) and endemic KS (87.5%), and higher than the patients with mental and/or physical deficiency (1.6%) and health professionals (1.1%). All analyzed groups had more HHV-8-seropositive samples for Lytic antibodies and higher titers of LANA antibodies, with exception for the health professionals. The highest LANA antibodies titers were found among KS patients groups. No other association was found. In conclusion, the obtained results points out CKD patients as a high prevalent population for HHV-8 infection, similar to HIV/Aids patients from the same geographic area. As far, it suggests that HHV-8 seropositive CKD patients should be followed up in order to verify whether LANA antibodies titers have prognostic value. In confirming this hypothesis, it may propose to include the use of HHV-8 serology in the screening testing in kidney pre-transplant.

Bartonella, a group of Gram negative facultative intracellular bacteria, are known to cause diseases, such as Cat Scratch Disease, Trench Fever and Carrion’s Disease, that involve angiogenesis during the infective cycle. B. bacilliformis, the etiological agent of Carrion’s Disease, causes a bi-phasic infection resulting in the formation of blood-filled angiogenic proliferative cutaneous nodules called verruga peruana. The work presented here was undertaken to characterize the mechanism by which these nodules are produced. Previous work in our laboratory suggested that the Bartonella henselae genome contains a homologue to the virB operon, a set of genes coding for a Type IV Secretion System (TFSS) that has been implicated in the pathogenesis of other α-2-proteobacteria. We identified virB operons in two additional Bartonella pathogens, B. quintana and B. clarridgeiae. No corresponding operon sequences were detected in B. bacilliformis DNA, however. This finding suggests that virB gene products are not required for verruga peruana formation. To continue our search for factors involved in B. bacilliformis-induced angiogenesis, we conducted a microarray analysis of differential gene expression in infected and uninfected endothelial cells. The results suggest similarities between later stage (36 hours) B. bacilliformis infection and that of HHV-8, the causative agent of Kaposi’s Sarcoma, particularly in relation to the host immune response. Finally, our research focused on the secreted factors that B. bacilliformis produces during its host infective cycle. Our data suggest that the B. bacilliformis homologue to the molecular chaperone GroEL not only induces angiogenesis in endothelial cells, but also protects endothelial cell tubule from the degradation seen when these cells are in the presence of live B. bacilliformis. In summary, the induction of verruga peruana nodules via B. bacilliformis may be the result of multiple factors over the course of persistent infection. Early infection may cause vascular damage, which induces VEGF and hypoxia factors. As infection persists, bacterial secretion of a unique GroEL may result in continued angiogenesis and the ensuing activation of immune cells, producing a localized environment of continual incomplete angiogenesis in areas of cutaneous infection.

Kaposi's sarcoma-associated herpesvirus (KSHV) causes several tumours and hyperproliferative disorders. Hypoxia plays an important role in KSHV lifecycle, as hypoxia-inducible factors (HIFs) are involved in the latent/lytic switch and affect other KSHV genes, and as KSHV infection can in turn enhance cellular levels of HIFs. Two KSHV-associated tumours tend to develop in settings of relative hypoxia; Kaposi's sarcoma (KS) often occurs in the lower extremities and primary effusion lymphoma (PEL) exists in pleural effusions. A better knowledge of the pathways that regulate KSHV infection in hypoxia is therefore essential for an improved understanding of viral infection and pathogenesis. MicroRNAs (miRNAs) have been shown to play important roles in regulating the expression of genes in oncogenesis, and herpesviruses, including KSHV, encode for miRNAs. This thesis describes a multidisciplinary approach toward understanding the mechanisms behind the hypoxia-regulated miRNA-mRNA networks in the context of KSHV infection. The question of miRNA and mRNA regulation through hypoxia, KSHV or both is addressed in this thesis by deep sequencing and gene expression assays as well as various transfection and functional assays. In chronically infected cells compared to uninfected controls, it is demonstrated that the majority of cellular miRNAs whose expression is affected are substantially down-regulated. A third of this down-regulation can be attributed to a single genomic region, 14q32 cluster, where miRNAs are lowly expressed in infected cells. In hypoxia, hsa-miR-210 is the only miRNA to be consistently up-regulated in the KSHVinfected cell lines subjected to deep sequencing in this study. Computational approaches additionally allowed for the investigation of mRNA targets. Inversely correlated miRNAmRNA target pairs were identified and distributed into canonical pathways and biological networks. Taken together, these results suggest that miRNAs affected by hypoxic stress and/or viral infection are implicated in the pathogenesis of KSHV-related diseases. It is expected that the outcomes of these studies will change our understanding of how KSHV uses the host RNA silencing machinery to its advantage and how this intersects with the use of the cell's response to hypoxia.

Thesis (D.Tech.: Radiography)-Dept. of Radiography, Durban Institute of Technology, 2006 xxiii, 166 leaves<br>The purpose of this study was to evaluate 99mTc- methoxyisobutylisonitrile (MIBI) imaging, in terms of sensitivity and specificity, for non invasively detecting extracutaneous involvement of Kaposi’s sarcoma (KS) and for differentiating pulmonary infection from malignancy in acquired immunodeficiency syndrome (AIDS) patients before and after treatment. Current investigations are invasive.

Background: Surgical disease related to HIV is scantily documented with a paucity of data detailing the manifestations of HIV in surgery especially in resource-poor, high prevalence settings such as in South Africa. This review provides an update on the topical issues surrounding HIV and surgery. Objectives: The objective of the study was to determine the incidence, pathogenesis, clinical presentation, aspects of diagnosis and management of: HIV- associated salivary gland disease in particular parotid gland enlargement; Kaposi’s sarcoma (KS) and lower limb lymphoedema; AIDS- related abdominal malignancies due to KS and lymphoma; Acalculous cholecystitis and HIV- cholangiopathy and HIV- associated vasculopathy. Methods: A collective review of the literature was performed and data sourced from a search of relevant electronic medical databases for literature from the period 2000 to the present date. Studies under each section were selected based on inclusion and exclusion criteria. Content analysis was used to analyse data. Results: The HIV pandemic has resulted in an increased frequency of benign lymphoepithelial cysts making it the commonest cause of parotidomegaly in most surgical practices. KS should be considered in the differential diagnosis of a patient with chronic lymphoedema. Lymphoedema may be present without cutaneous lesions, making clinical diagnosis of KS difficult. The gastrointestinal tract is the commonest site of extra- cutaneous KS. Surgical management of the lymphoma patient is restricted nowadays to determining the diagnosis and in some cases to evaluate disease stage. Highly active antiretroviral therapy (HAART) is an important part of the management of biliary tract conditions in addition to relevant surgical procedures. HIV- vasculopathy represents a distinct clinico- pathological entity characterized by a vasculitis with probable immune- mediated or direct HIV- related injury to the vessel wall. Conclusion: The rising incidence of HIV in South Africa and other developing countries has been associated with new and unusual disease manifestations requiring surgical management for diagnostic, palliative or curative intent. It is crucial that surgeons remain abreast of new developments related to the challenging spectrum of HIV and its protean manifestations.<br>Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2012.