The follow-up of a cohort of anti-hiv seropositive haemophiliacs for up to 15 years from seroconversion

111 men with haemophilia registered at the Royal Free Hospital Haemophilia Centre became infected with HIV between 1979 and 1985 after treatment with infected blood products. These men have been followed for up to 15 years since HIV seroconversion. This thesis presents an epidemiologic follow-up of this cohort of patients. By the end of 1994, 47 men had developed AIDS and 45 had died, Kaplan-Meier progression rates of 56.5[percent] (9570 confidence interval 39.5-73.6) and 46.9[percent] (9570 confidence interval 35.6-582) by 14 years after seroconversion respectively. Prior to the development of AIDS, 82 of the men had developed at least one more minor condition indicative of their HIV infection. Older individuals and those who seroconverted prior to 1981 and from 1983 onwards appear to have a more rapid progression of disease. The CD4 lymphocyte count, which drops throughout infection, is a strong prognostic marker for disease progression. The rate of CD4 decline, the Immunoglobulin A level and the development of p24 antigenaemia all add some additional prognostic information to that provided by the most recent CD4 count alone. In contrast, the CD8 lymphocyte count simply identifies those individuals with the lowest and most rapidly declining CD4 counts. Whilst the beta-2 microglobulin level appears to provide additional prognostic information to the CD4 count at high CD4 levels, it is of less value at lower counts. The development of a bacterial infection prior to AIDS suggests that a patient's condition is likely to deteriorate, irrespective of their immune status. Despite being the best marker of progression, the CD4 count is, unfortunately, measured imperfectly. This has the effect of reducing the apparent relationship with disease progression and may lead to erroneous conclusions about the value of other covariates in a proportional hazards model

In vitro expanded human CD4+CD25+ regulatory T cells suppress effector T cell proliferation.

Regulatory T cells (Tregs) have been shown to be critical in the balance between autoimmunity and tolerance and have been implicated in several human autoimmune diseases. However, the small number of Tregs in peripheral blood limits their therapeutic potential. Therefore, we developed a protocol that would allow for the expansion of Tregs while retaining their suppressive activity. We isolated CD4+CD25 hi cells from human peripheral blood and expanded them in vitro in the presence of anti-CD3 and anti-CD28 magnetic Xcyte Dynabeads and high concentrations of exogenous Interleukin (IL)-2. Tregs were effectively expanded up to 200-fold while maintaining surface expression of CD25 and other markers of Tregs: CD62L, HLA-DR, CCR6, and FOXP3. The expanded Tregs suppressed proliferation and cytokine secretion of responder PBMCs in co-cultures stimulated with anti-CD3 or alloantigen. Treg expansion is a critical first step before consideration of Tregs as a therapeutic intervention in patients with autoimmune or graft-versus-host disease

Human Leukocyte Antigen (HLA) and Killer Immunoglobulin-Like Receptors (KIR) in HIV-2 Infection

In West Africa, the Acquired Immunodeficiency Syndrome (AIDS) is caused by both types of Human Immunodeficiency Virus HIV-1 and HIV-2 and the majority of people infected with HIV-2 remain healthy for over 15 years. The major goal of this work was to determine and describe genetic variants associated with phenotypic changes at the population level and study their role in pathogenesis and immune response. Studies presented in this thesis were carried out in two well established HIV-2 cohorts in Guinea Bissau and Gambia. Using recent tools in molecular medicine i.e. sequence-based techniques (SBT) (Chapter 2), we determined and comprehensively described variations at the two most polymorphic regions of the human genome: HLA and KIR gene complexes located on chromosomes 6 and 19, respectively, in these cohorts (Chapters 3 and 6). The data showed high heterogeneity in allele and genotype frequencies between the studied populations. Furthermore, we related the presence of gene variants to HIV-2 antibody status and study their effect on markers of disease progression, notably CD4+ T cell count and viral load (Chapter 4). Here we showed for the first time that HLA-B*1503 associates with poor prognosis after HIV-2 infection and HLA-B*0801 with susceptibility to HIV-2 while the compound genotypes KIR2DL2+HLA-C1 and KIR2DS2+HLA-C1 protect against HIV-2 acquisition in the Manjako ethnic group. None of the HLA class I alleles/haplotypes and KIR gene profiles was found to influence HIV-2 infection in the second cohort, which was of mixed ethnic origin (Chapter 5). In general, we observed that alleles previously shown to be associated with HIV-1 disease in western populations showed no effect in HIV-2 infection. This emphasizes the need to study HLA and HLA/KIR combinations in different populations in order to better inform subsequent vaccine design and evaluation in target populations

Modulation of HIV-specific T cell responses during standard antiretroviral treatment and immunotherapy

Seule une minorité des individus infectés par le virus de l’immunodéficience humaine (VIH) développe une réponse immunitaire capable de contrôler le virus. Chez la plupart des individus, on observe un échappement virologique et un épuisement des lymphocytes T CD8+ spécifiques du VIH. L’infection chronique non-traitée altère également les lymphocytes T CD4+ spécifiques du VIH caractérisé par l’expression accrue des récepteurs co-inhibiteurs et une signature des cellules auxiliaires T folliculaires (Tfh). La thérapie antirétrovirale (TAR) est très efficace pour supprimer durablement la charge virale dans le plasma. Néanmoins, elle ne permet pas une éradication complète du VIH car le virus persiste, intégré dans le génome des cellules réservoirs, desquelles le virus réapparaît lors de l’interruption de la thérapie. Cela démontre que l'immunité adaptive spécifiques du VIH n'est pas restaurée. Les anticorps neutralisants à large spectre (bNAbs) représentent une alternative potentielle à la TAR. En plus de la neutralisation du virus – et contrairement à la TAR – les bNAbs ne limitent pas la disponibilité de l'antigène et peuvent engager le système immunitaire. L'administration de bNAbs à des macaques rhésus induit des réponses immunitaires adaptatives associées à un contrôle prolongé de la virémie, mais cela n’a pas été établi chez l’Homme. Dans cette thèse, nous avons donc exploré la modulation des réponses des lymphocytes T spécifiques du VIH lors d'une TAR standard et d’une immunothérapie utilisant des bNAbs. Dans un premier objectif nous avons analysé la modulation persistante des réponses des lymphocytes T CD4+ spécifiques du VIH chez les individus sous TAR. Nous avons pu démontrer l'expansion persistante des Tfh spécifiques au VIH avec des caractéristiques phénotypiques et fonctionnelles les distinguant des Tfh spécifiques d’antigènes viraux comparatifs (cytomégalovirus, virus de l’hépatite B). Ces caractéristiques ont été induites au cours de l’infection chronique non-traitée, persistaient pendant la TAR et étaient associées au réservoir du VIH compétent pour la traduction. Ces données suggèrent qu’une stimulation antigénique persistante, malgré une TAR efficace, maintient des modifications immunologiques notamment au niveau des Tfh. Dans un second objectif, nous avons caractérisé les réponses T spécifiques du VIH à la suite d’un traitement utilisant des bNAbs et une interruption structurée de la TAR (IST). Des individus inclus dans une étude clinique de phase Ib ont reçu une perfusion d’une combinaison des bNAbs 10-1074 et 3BNC117 et ont démontré une suppression virale prolongée après l’IST. Chez ces participants, nous avons observé une augmentation des réponses immunitaires des lymphocytes T CD8+ et CD4+ spécifiques du VIH due à l'expansion des réponses immunitaires préexistantes et au développement de réponses ciblant de nouveaux épitopes. Cela suggère que la combinaison d’un traitement par bNAbs avec l’IST est associée au maintien de la charge virale plasmatique indétectable et à une intensification de la réponse immunitaire des lymphocytes T spécifiques du VIH. Nos travaux permettent une meilleure compréhension des réponses des lymphocytes T spécifiques du VIH au cours de la TAR et lors d’une immunothérapie. Ils peuvent contribuer au développement de stratégies thérapeutiques plus efficaces visant à contrôler la réplication virale sans la TAR.Only a small fraction of individuals infected with the human immunodeficiency virus (HIV) develops effective immune responses able to control the virus. In most individuals, the virus escapes the antiviral immune response and HIV-specific CD8+ T cell responses become exhausted. Untreated progressive HIV infection also leads to alterations in HIV-specific CD4+ T cells. This includes increased expression of co-inhibitory receptors and skewing towards a T follicular helper cell (Tfh) signature. Antiretroviral therapy (ART) is highly effective in controlling the HIV viral load at undetectable levels in the plasma. However, ART does not represent a cure as the virus integrates into the genome of infected cells from where the virus rebounds once ART is stopped. This demonstrates that the HIV-specific T cell immunity is not restored. However, the changes that are introduced during progressive infection and that are maintained after viral suppression with ART are poorly known. Broadly neutralizing antibodies (bNAbs) represent a potential alternative to ART. In addition to virus neutralization and unlike ART, bNAbs to do not limit HIV antigen availability and can engage the immune system. bNAb administration elicited adaptive immune responses that were associated with long-lasting viral control in a simian animal model but this has not been established in HIV-infected individuals. In this thesis, we therefore proceeded to study the modulation of HIV-specific T cell responses during standard ART and after an immunotherapeutic intervention using bNAbs. The first objective was to better understand persistent modulation of HIV-specific CD4+ T cell responses in ART-treated individuals. Our results demonstrated the persistent expansion of HIV-specific Tfh cell responses with multiple phenotypic and functional features that differed from Tfh cells specific for comparative viral antigens (cytomegalovirus, hepatitis B virus). These features were induced during chronic untreated HIV infection, persisted during ART and correlated with the translation-competent HIV reservoir. This suggests that persistent HIV antigen expression, despite effective ART, maintains these altered immunological features specifically for Tfh responses. For the second objective, we characterized changes in the HIV-specific CD8+ and CD4+ T cell immunity after bNAb treatment and analytical treatment interruption (ATI). For this, we used samples obtained from participants enrolled in a clinical phase Ib study that received combined infusion of bNAbs 10-1074 and 3BNC117 and demonstrated prolonged viral suppression after ATI. In these individuals, we detected an increase of HIV-specific CD8+ and CD4+ T cell responses during ART interruption when compared to baseline. Increased T cell responses were due to both expansion of pre-existing responses and the emergence of responses to new epitopes. In contrast, HIV-specific T cell responses remained unchanged in ART-treated individuals who did not receive bNAb infusions. This suggests that bNAb treatment and ATI is associated with increased HIV-specific T cell immunity while viral suppression is maintained. Together our results contribute to a better understanding of HIV-specific T cell responses during ART and immunotherapy treatment. Our findings may help to develop more effective HIV treatment strategies to improve the host’s immune system so that HIV can be controlled without the need for ART

Physical activity and hypertension in South African adults

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.5 South Africa LicenseEstimates suggest that approximately 6-million South Africans have hypertension, with half classified as stage 1 (mild). Mindful of the cost of lifelong drug therapy, the South African Hypertension Society guidelines suggest delaying drug therapy through lifestyle modification (increased physical activity and weight management) in all but those with the highest risk. This pilot study examined the relationship of BP with physical activity and bodyweight in black South African adults employed in physical occupationsNon peer reviewe

External quality assessment of HIV-1 DNA quantification assays used in the clinical setting in Italy

none18no: Total cell-associated HIV-1 DNA is a surrogate marker of the HIV-1 reservoir, however, certified systems for its quantification are not available. The Italian HIV DNA Network was launched to validate HIV-1 DNA quantification methods in use at University and Hospital labs. A quality control panel including HIV-1 DNA standards, reconstructed blood samples (RBSs) and DNA from different HIV-1 subtypes was blindly tested by 12 participating labs by quantitative real-time PCR (n = 6), droplet digital PCR (n = 3) or both (n = 3). The median 95% hit rate was 4.6 (3.7-5.5) copies per test and linearity in the tested range was excellent (R2 = 1.000 [1.000-1.000]). The median values obtained across labs were 3,370 (2,287-4,245), 445 (299-498), 59 (40-81) and 7 (6-11) HIV-1 DNA copies, for the 3,584, 448, 56 and 7-copy standards, respectively. With RBSs, measured values were within twofold with respect to the median in two thirds of cases. HIV-1 subtypes were missed (CRF01_AE by 3 labs) or underestimated by > 1 log (subtypes A, C, D, F by one lab; CRF01_AE by one lab; CRF02_AG by one lab). The overall performance was excellent with HIV-1 DNA standards, however detection of different HIV-1 subtypes must be improved.openVicenti, Ilaria; Dragoni, Filippo; Giannini, Alessia; Casabianca, Anna; Lombardi, Francesca; Di Sante, Laura; Turriziani, Ombretta; Racca, Sara; Paolucci, Stefania; Lai, Alessia; Bon, Isabella; Abbate, Isabella; Rozera, Gabriella; Belmonti, Simone; Scutari, Rossana; Alteri, Claudia; Saladini, Francesco; Zazzi, MaurizioVicenti, Ilaria; Dragoni, Filippo; Giannini, Alessia; Casabianca, Anna; Lombardi, Francesca; Di Sante, Laura; Turriziani, Ombretta; Racca, Sara; Paolucci, Stefania; Lai, Alessia; Bon, Isabella; Abbate, Isabella; Rozera, Gabriella; Belmonti, Simone; Scutari, Rossana; Alteri, Claudia; Saladini, Francesco; Zazzi, Maurizi

Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation

BACKGROUND: Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established. OBJECTIVE: To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease. DATA SOURCES: We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists. METHODS: We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted. RESULTS: Given a cost-effectiveness threshold of £20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of £9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of £28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (£30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a £20,000 threshold (ICER: £19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of £822. LIMITATIONS: A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments. CONCLUSIONS: Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD. STUDY REGISTRATION: This study is registered as PROSPERO CRD42011001561. FUNDING: The National Institute for Health Research Health Technology Assessment programme