Although there have been recent advances in HIV treatment, women still do not have a means to protect themselves from sexual transmission of HIV discreetly. Microbicides are products that would be applied vaginally to prevent HIV acquisition. Several microbicide products are being tested for their effectiveness in preventing HIV, and further studies of cervical barriers, such as the diaphragm, are planned. If found effective introduction and distribution systems need to be developed quickly to ensure women can access products and introduce them into their relationships. This study looks at determinants of women's demand for different barrier methods for HIV prevention to learn lessons for the introduction of new technologies such as microbicides and the diaphragm. A discrete choice experiment (DCE) was undertaken to identify critical factors to women's uptake of products. An iterative approach to the development of the DCE tool was taken. Qualitative group and individual interviews with women generated a wide range of potential factors influential to demand. An attribute identification workshop was introduced as a systematic method to reduce these attributes to the most important factors and identify the best way to represent them in the survey; this included the presentation of product effectiveness by the risk of HIV acquisition and becoming pregnant. During this workshop, women were given individual worksheets on which to rank the importance of the different attributes and levels in their decision to introduce, use and collect products. This provided individual responses in a group interview setting, which generated quantitative ranks on importance of attributes and their levels. Subsequently, a representative community survey was conducted among 1017 women in three Johannesburg townships. Women were asked questions about their socio-demographic backgrounds, their reproductive health histories and their preferences for different barrier methods and their distribution and promotion were elicited by a DCE. This study showed the usefulness of the attribute identification workshop in providing a structured framework for using women's attribute and level rankings to identify the importance of attributes generated in qualitative interviews and reduce these into a feasible and comprehensible DCE instrument. The analysis of women's preferences showed that there was a strong interest in the new barrier methods, microbicides in particular. The level of HIV effectiveness was very important in women's choices and will have an important impact on product uptake. Additionally, women who were successful in using condoms were predicted to have lower uptake of new products. Preferences for different distribution channels and ways of collecting product or advertising messages did not vary between products. However there was diversity in women's preferences for advertising messages, in particular in their valuation of promoting products for enhanced sexual pleasure, where employed women rated it positively. This study shows that women are very capable of using hierarchical messages about HIV effectiveness to make informed choices about how to best protect themselves from HIV in their situations. The different barrier methods can be distributed through similar distribution systems, but having a range of advertising strategies is likely to increase uptake of products by widening their appeal across different groups of women.

Vaginal microbicides are pharmaceutical products in development that are designed to reduce the sexual transmission of HIV in women. They are commonly known as a `woman-controlled technology' and tool for women's empowerment, and form part of a burgeoning field of clinical research into new biotechnologies for HIV prevention. Little work has critically examined how such research and new technologies are produced, and how they in turn contribute to the construction, maintenance or deconstruction of gender relations. Adopting a Foucauldian understanding of power and discourse, and using theoretical insights from science and technology studies (STS), this research explores the coproduction of gender and technology through the case study of vaginal microbicides. 'T'his account of the relations between science, society and technology draws on empirical research conducted in the UK and Zambia with the pharmaceutical industry, trialists, trial participants and trial communities. It interrogates the techniques of power through which transnational scientific networks are mobilised to test new products, such as microbicides, and how these affect scientific practices, knowledges and identities across socio-geographic boundaries. It attends to the potential multiplicity of interventions in diverse contexts, calling into question the presumed stability and singularity of both the randomized controlled trial and vaginal microbicides. This research makes an empirical contribution to knowledge about new biomedical technologies for HIV prevention, detailing the transformation that may occur when technologies travel from their site of development to their site of use. It provides a detailed analysis of the interaction between gender performativity and science in action, challenging the sense of `gendered' technologies for a `feminized' epidemic. Theoretically, it contributes to debates about the role of social theory in public health research and reconstructivist agendas in STS, concluding with a model for greater collaboration between health technology designers, evaluators, critics, and users.

A major barrier to universal access to antiretroviral treatment (ART) in Uganda is the critical shortage of trained healthcare workers, particularly doctors. Although there are plans to legalise nurses to provide ART, little is known about the potential barriers and facilitators to the development and implementation of effective nurse-led ART clinics in Uganda. Thus, this study sought to understand the factors influencing the introduction of nurse-led ART clinics in Uganda as well as to determine nurses’ and doctors’ competencies in delivering HIV care to inform the design of strategies that would enhance their success. To this end, descriptive cross-sectional studies through a questionnaire survey, semi-structured interviews, and focus group discussions (FGDs) were conducted with numerous stakeholders including patients. HIV clinical vignette tests were used to assess doctors’ and nurses’ competencies in delivering ART. The results revealed that nurse-led ART clinics were already widespread in Uganda, albeit the lack of a policy allowing them to operate. Moreover, their successful development and implementation is critically dependent on nurses’ competence, self-confidence, motivation, authority, and autonomy, as well as on the availability of systems and human resource support and on the acceptability of nurses as providers of ART by patients and other stakeholders. Major challenges identified include the lack of patients’ and cmmunity support, the absence of legal and regulatory frameworks, and a weak general health system including inadequate equipment, supervision support and mentoring, among others. In conclusion, this study found that nurse-led ART clinics are already operating on a wide scale in Uganda, although on an ad hoc basis, and are viewed by stakeholders as a key strategy for scaling up human immune deficiency virus HIV services including ART. Now may be the appropriate time to plan adequately for the legalised and regulated development and implementation of these clinics while addressing the numerous factors that influence nurses’ ability and capacity to deliver HIV services efficiently and effectively.

Literature and other background information on prevention of mother-to-child transmission of HIV (PMTCT) and maternal syphilis screening programmes in Tanzania reveal that little has been documented on accessibility and utilization of these services. This thesis presents the results from a research conducted in Mwanza city, Tanzania to assess the operational performance of PMTCT and maternal syphilis screening and treatment during pregnancy, at delivery and in the postnatal period. From different sub-studies conducted at the antenatal clinics (ANC) and in the maternity ward for this research, a number of missed implementation opportunities were identified. A review of records found that 24% of pregnant women who delivered in hospital left the maternity ward with unknown HIV status and 50% of HIV-positive women tested at ANC did not receive Antiretroviral therapy (ART) for PMTCT. A cross-sectional study at the maternity ward found that 12% of pregnant women who were not screened for syphilis, 27% of RPR-positive women who were not treated at ANC, and all infants of RPR-positive women did not receive any intervention to prevent congenital syphilis. Forty-one percent of HIV-positive women recruited in the cohort study successfully completed all PMTCT interventions. Only 18% of HIV-positive women identified through PMTCT were successfully referred to, and attended an adult care and treatment clinic (CTC). Of 403 HIV- positive women in the cohort study, 50% did not intend to get pregnant and by four months postpartum, 20% of them reported to have not received any counselling on family planning. HIV-positive women who did not receive counselling on FP use were at a higher risk of not using contraception compared to those who were counselled (adj. OR=6, 95% Cl; 2.8-12.9). About 27% of HIV-positive mothers were not counselled regarding infant feeding and 40.2% of women who were not counselled on infant feeding were undecided on how to feed their infants before they left the hospital compared to only 2.5% of women who were counselled (P<O.OOl) It was found that pregnant women attending ANC for the first time during pregnancy spent between three and 5.5 hours at the clinic, on average, 78% of this time was spent waiting for services. 6 Fewer ANC visits, attending private or rural ANC facilities, failure to attend a CTC prenatally, and lack of knowledge among users and provider of health services were factors found to hamper the performance of the programmes. Integration of these programmes at all levels and training of health workers in basic components of the programmes are fundamental to the successful implementation of the programmes.

Background: The relationships between human papillomavirus (HPV) and HIV, in an African context are limited. Given the large number of women living with HIV (WLHIV) accessing antiretroviral therapy (ART), it is important to establish associations of HIV-related factors with high-risk (HR)-HPV and cervical intraepithelial neoplasia (CIN). Design: Prospective cohort of WLHIV attending HIV treatment centres in Ouagadougou, Burkina Faso (BF) and Johannesburg, South Africa (SA). Methods: At baseline and endline (median 16 months), cervical samples and biopsies were analyzed for HPV genotyping (InnoLiPA) and by histology. HPV serology targeting 15 HPV types (12 HR) was by multiplexed pseudovirion-based serological assay. Methylation of a human gene EPB41L3 and HPV16 was measured by pyrosequencing. Logistic regression was used to estimate associations of HIV-related factors with HR-HPV and CIN2+ outcomes. Results: Among 1238 enrolled WLHIV (BF=615; SA=623) HR-HPV prevalence was 59.1% in BF and 79.1% in SA. CIN2+ prevalence was 5.8% in BF and 22.5% in SA. Prolonged ART use (>2 years) was associated with lower HR-HPV prevalence in BF and lower CIN2+ prevalence compared to short-duration ART users and ART-naïve participants in SA. Among 963 (77.8%) women seen at endline, HR-HPV persistence was 41.1% in BF and 30.2% in SA; CIN2+ incidence over 16-months was 1.2% in BF and 5.8% in SA. HR-HPV persistence was lower among those with prolonged ART compared to ART-naïve and short-duration ART users. CIN2+ incidence was reduced among women on ART in SA. HPV seroprevalence and seropersistence were high (93% and 95%, respectively). Seroconversion was 23.1%, and was higher among recent ART users (≤2 years) and among those with type-specific DNA persistence compared to those who cleared infection. v The human gene EPB41L3 showed elevated methylation in CIN2+ compared to ≤CIN1 (Mann Whitney U p= < 0.001) at baseline. Higher methylation levels were found among recent ART users (≤2 years) and women with CD4 ≤200 cells/mm3. Conclusion: WLHIV in BF and SA have high rates of HR-HPV and CIN2+, and WLHIV in SA have higher CIN2+, linked with poorer control of HIV and higher frequency of cofactors for HR-HPV and CIN2+. Prolonged and effective ART is important in controlling HR-HPV and the development of CIN2+. WLHIV are infected with multiple HR-HPV types and there is limited evidence that HPV antibodies protect against same-type reinfection. WLHIV may benefit from vaccination using a multivalent vaccine. DNA methylation of a tumour suppressor gene EPB41L3 is elevated among women with CIN2+ and shows promise as a biomarker test for CIN2+ prediction among WLHIV.

Peanut allergy affects 1-2% of UK schoolchildren. Children with egg allergy are at increased risk. The diagnosis of peanut allergy in this group of children is challenging, with current diagnostic techniques being inadequate. Clarification of peanut allergy status in egg-allergic, peanut-sensitised children is complicated and frequently includes the need for an oral provocation challenge. This places considerable pressure on day-case services, poses a potential risk to the child and carries health economic implications. Recent research has proposed the measurement of specific IgE concentrations to the peanut component Ara h 2 to be a better test for the differentiation of allergy and tolerance than existing methods. The present study attempts to improve the diagnostic process for this group of children. The primary aim was to investigate the diagnostic value of measuring Ara h 2-specific IgE concentrations in predicting a clinical reaction to peanut. 105 eligible children were prospectively recruited via the tertiary allergy clinic at Bristol Royal Hospital for Children. Children were subjected to a peanut skin prick test and specific IgE testing to whole peanut and Ara h 2 followed by an oral provocation challenge. Children were allocated to either the peanut allergic or tolerant group. Outcomes were related to all three tests. The peanut skin prick test and whole-peanut specific IgE were poor discriminators between allergy and tolerance. Ara h 2 was the best predictor of peanut allergy, but had greater clinical utility as part of a two-step approach. Receiver-operator curve construction identified optimal cut-off values of 6mm for peanut skin prick testing, 0.39kUA/L for Ara h 2-specific IgE concentrations and 1.08kUA/L for whole peanut specific IgE. These were included in a diagnostic two-step model. When used in isolation, specific IgE concentrations to Ara h 2 were unable to replace the need for an oral provocation challenge for the majority of egg-allergic, peanut-sensitised children.

In recent years evidence has accumulated which suggests that the brain may not be the immunologically privileged site it was once considered to be. It is now widely accepted that T lymphocytes perform surveillance functions in normal brain parenchyma. However as yet there are no reports of B lymphocytes entering brain parenchyma in the healthy state. This study aimed first to determine the prevalence of B lymphocytes in normal human brain, and subsequently whether advancing human immunodeficiency virus (HIV) infection leads to changes in the brain B lymphocyte population which might contribute to the increased risk of lymphoma seen in aquired immunodeficency syndrome (AIDS). Our results show that B lymphocytes do enter all areas of normal brains in very low numbers and that the B lymphocytes within the brain parenchyma display an activated (CD23 positive) phenotype. In contrast intravascular B lymphocytes had a much lower expression of activation markers. B lymphocytes were found in increased numbers in both the brain parenchyma and perivascular spaces of pre-AIDS brains. However brains from the majority of AIDS subjects, including those with primary central nervous system lymphoma (PCNSL) (out with the area of neoplastic involvement) contained fewer B lymphocytes than normal or pre-symptomatic HIV infected brains. A subset of AIDS brains, previously shown to have pleomorphic lymphoid infiltrates in the perivascular spaces had significantly increased numbers of B lymphocytes in both the brain parenchyma and perivascular spaces, which led us to hypothesise that these may represent a pre-malignant PCNSL state. These pleomorphic lymphoid infiltrates were shown to be polyclonal, as defined by immunoglobulin gene re-arrangements, in contrast to PCNSL in which two of three tumours were found to be monoclonal. Virtually all AIDS related PCNSL are known to be EBV positive, in contrast to non-HIV PCNSL and non-CNS AIDS related lymphomas. We examined the EBV status of brain parenchymal B lymphocytes to investigate whether EBV positive B lymphocytes are more frequent in HIV infected brains than normal thus explaining the propensity for CNS lymphomas in AIDS. In-situ hybridisation (ISH) studies showed EBV positive cells only in the tumours of AIDS related PCNSL cases. PCR based studies detected high EBV copy numbers in PCNSL tumour tissue and low copy numbers from AIDS cases with pleomorphic lymphoid infiltrates. As none of the B lymphocytes in this latter group were EBV ISH positive, and this appears to be a prerequisite for PCNSL development, we find no evidence that pleomorphic infiltrates represent a pre-malignant PCNSL state. However both PCNSL and AIDS associated pleomorphic infiltrates were associated with expression of the B lymphocyte chemoattractant, stromal cell derived factor-1 (SDF-1) in the brain. Humoral responses have been shown to play an important part in the immune response to many neurtropic viruses, therefore we assessed the role of B lymphocytes in HIV encephalitis (HIVE). Our results show that a slight increase in the brain B lymphocyte population occurs in HIVE compared to non-HIVE AIDS brains. However this response is far smaller than that seen either in pre-AIDS non-HIV encephalitis or in non-immunocompromised viral encephalitis. Finally we have shown that the presence of B lymphocytes in the brain is not associated with damage or disruption to the blood-brain barrier.

The prevalence of allergic diseases, such as asthma, rhinitis, eczema and food allergies has increased dramatically over the last few decades and is now a major health and economic burden throughout the developed and developing worlds. Type I (immediate) hypersensitivity reactions are mediated by immunoglobulin E (IgE) responses directed against innocuous environmental antigens, such as pollen, housedust mites or animal dander. It is the resulting release of pharmacological mediators by IgE-sensitised mast cells that cause the symptoms of asthma and allergic rhinitis. The induction of IgE is dependent on CD4+ T cells of the Th2 phenotype which are characterised by the production of specific cytokines (IL-4, IL-5 and IL-13). In contrast, the presence of allergen reactive Thl cells, which secrete IFN-y, in nonallergic healthy individuals suggests that Thl immunity is not damaging to the host and is possibly associated with protective immunity. It is clear with the high incidence of atopic disorders combined with existing treatments, which are in general symptomatic, that there is a requirement for new therapeutic agents. Since CD4+ T cells play an important role in the response to allergens they are an obvious target for drug development and they can be targeted directly, with the aim of inducing specific tolerance. A second strategy for inhibiting the synthesis of Th2 cytokines may be achieved by promoting the induction of Thl immunity. Therefore, the main aim of this study was to investigate these different approaches for the modulation of Th2 immunity to the major house dust mite allergen Der p 1. Tolerance induction or the promotion of Thl responses were attempted by intranasal delivery of antigen alone, by the systemic or mucosal delivery of Der p 1 in PLG polymer microparticles (MEA) and finally, by intranasal administration with chitosan, an enhancer of epithelial permeability. In order to investigate the efficacy of the regimens of vaccination, an adjuvant free model of Th2 cytokine-mediated allergic inflammation was developed in vivo in H-2b mice. Vaccination with microencapsulated antigen failed to elicit a Thl response or induce tolerance despite altering the kinetics, dose and method of delivery. In fact, the Th2 phenotype was usually exacerbated following administration of MEA/Der p 1 particles. Intranasal co-administration of antigen with chitosan inhibited Th2 cytokine production but not as a result of the tolerance induction. Similarly, high doses of soluble peptide delivered intranasally, failed to tolerise allergen-specific Th2 immunity. In conclusion, the redirection of the Th2 immune response and the induction of tolerance were difficult to achieve. However, chitosan which was not as extensively researched as the other approaches may prove to be of therapeutic value.

The Human Immunodeficiency Virus (HIV) pandemic still remains a major public health concern worldwide. The World Health Organization (WHO) estimates that approximately over 70% of people living with HIV in the world are in sub-Saharan region. Malawi is one of the worst affected countries in sub-Saharan Africa with prevalence reaching up to 16% in some areas. Recent study reports, largely in Africa, comparing outcomes for HIV patients with Kaposi’s sarcoma (HIV/KS) and HIV patients without KS indicate poor prognosis and poor health outcomes amongst HIV patients with KS. While efforts are being made to improve the management and care for the HIV/KS patient group, there is also need for continued efforts to better understand the survival patterns in this patients. The work presented in this thesis attempts to investigate the survival patterns in different patient subgroups in HIV cohorts in Malawi by using advanced and novel statistical techniques with an ultimate aim of informing targeted patient treatment and management practices. In this thesis, we aim to address the following four objectives; (1) to identify risk factors for mortality among HIV patients diagnosed with Kaposi’s sarcoma during routine initiation of ART, (2) to model the survival pattern among HIV patients diagnosed with KS, (3) to model local geographical variations in survival among HIV patients on ART, (4) to quantify transition dynamics in HIV and TB co-infection using multi-state modelling. For the first two objectives, we considered extended Cox models and parametric models. We also used a novel approach of accounting for high attrition in cohorts in which we used a ’gold-standard’ data to compare survival in our cohort. Sensitivity analyses indicated consistencies in our approach providing an insight into how model results change when using this comparison approach. Overall We noted an early mortality with most patients dying in the first five months after starting HIV treatment. Patients with TB and the patients who started in the early era of ART were significantly at risk of dying. The model diagnostics indicated that (i) a random effects Cox/Log-Gaussian frailty model and (ii) a flexible parametric proportional hazards model, describe the risk of mortality in the HIV/KS patients well. For the third objective, spatial survival models were considered. The study showed existence of possible residual spatial variation in survival after adjusting for age, sex, KS status, TB status and unobserved individual frailties. To further aid our understanding, we used the choropleth maps to indicate areas with substantially high probability of mortality risk at different cut-off values. These results highlight the local geographical variations in survival in HIV populations, an element more often ignored in most studies on HIV data. For the last objective, we considered the homogeneous continuous time multistate Markov models. In this study we found that patients in TB free status had a relatively higher probability of transitioning to being diagnosed with TB compared to dying while in TB free status. However, the cumulative transition hazards for the ’TB free ! death’ transitions compared to the "TB free ! TB infection" transitions were only higher during the early days of HIV treatment. This result emphasize how early periods after starting HIV treatment is crucial to ensure better prognosis. We also noted significant gender differences in the ’TB-free ! death’ transitions. It is anticipated that the findings in this thesis will help to inform treatment and management practices of HIV patients. The findings provide clear outcome pathways taken by HIV/TB patients before experiencing a terminal outcome. More importantly, the findings could help inform policies aimed at improving overall survival in HIV cohorts by establishing targeted patient management and treatment strategies and also formulating a more efficient triage system for care and treatment of particular group of patients.

There is a relative paucity of information about the immune system within the female lower genital tract. This study had three aims. Firstly, to investigate the distribution and function of immunocompetent cells within the ectocervix and to establish the components of humoral immunity within the normal female lower genital tract. Secondly, to determine the effects of HIV infection on these parameters. Thirdly, to identify alterations in cellular and humoral immunity in the context of cervical intraepithelial neoplasia, with and without HIV co-infection. Cervical tissue samples were studied using standard immunohistological techniques and cervicovaginal secretions were analysed by radial immunodiffusion, and by the ELISA method. Normal cervical tissue showed high proportions of primed memory CD4+ T-cells (CD45RO+) and cytotoxic CD8+ cells (CD8+TIA-1+). The majority of epithelial macrophages were of the inducer-type (D1+D7-) and the majority of stromal macrophages were mature phagocytes (D1-D7+) with very few suppressive macrophages (D1+D7+). Although the cytokines IL-ip, TNF-a and TGF-Pi were detected in vaginal secretions, only TNF-a appeared cell-associated in cervical tissues. Relatively high concentrations of IgG and IgA occurred in cervicovaginal secretions. This suggests that the normal female genital tract possesses a reactive immune system with a high proportion of primed activated cells. Cervical biopsies from HIV-infected women showed reversal of the CD4+:CD8+ T-cell ratio. Despite greater proportions of activated T-cells and epithelial macrophages, there was no increase in cytolytic potential. There was an increase in suppressive macrophages and a fall in Langerhans' cell numbers. These changes may facilitate the sexual transmission of HIV infection. The emergence of CIN was associated with greater proportions of activated and cytolytic T-cells. The CIN+HIV+ group showed lower epithelial inducer macrophage proportions and higher suppressive cells. The combination of these factors may contribute to the susceptibility of HIV-infected women to develop CIN, as well as to the rapid progression of CIN in this group.