Impaired CD4 T Cell Memory Response to Streptococcus pneumoniae Precedes CD4 T Cell Depletion in HIV-Infected Malawian Adults

Objective: Invasive pneumococcal disease (IPD) is a leading cause of morbidity and mortality in HIV-infected African Adults. CD4 T cell depletion may partially explain this high disease burden but those with relatively preserved T cell numbers are still at increased risk of IPD. This study evaluated the extent of pneumococcal-specific T cell memory dysfunction in asymptomatic HIV infection early on in the evolution of the disease. Methods: Peripheral blood mononuclear cells were isolated from asymptomatic HIV-infected and HIV-uninfected Malawian adults and stained to characterize the underlying degree of CD4 T cell immune activation, senescence and regulation. Pneumococcal-specific T cell proliferation, IFN-c, IL-17 production and CD154 expression was assessed using flow cytometry and ELISpot. Results: We find that in asymptomatic HIV-infected Malawian adults, there is considerable immune disruption with an increase in activated and senescent CD4+CD38+PD-1+ and CD4+CD25highFoxp3+ Treg cells. In the context of high pneumococcal exposure and therefore immune stimulation, show a failure in pneumococcal-specific memory T cell proliferation, skewing of T cell cytokine production with preservation of interleukin-17 but decreased interferon-gamma responses, and failure of activated T cells to express the co-stimulatory molecule CD154. Conclusion: Asymptomatic HIV-infected Malawian adults show early signs of pneumococcal- specific immune dysregulation with a shift in the balance of CD4 memory, T helper 17 cells and Treg. Together these data offer a mechanistic understanding of how antigen-specific T cell dysfunction occurs prior to T cell depletion and may explain the early susceptibility to IPD in those with relatively preserved CD4 T cell numbers

Incomplete Recovery of Pneumococcal CD4 T Cell Immunity after Initiation of Antiretroviral Therapy in HIV-Infected Malawian Adults

HIV-infected African adults are at a considerably increased risk of life-threatening invasive pneumococcal disease (IPD) which persists despite antiretroviral therapy (ART). Defects in naturally acquired pneumococcal-specific T-cell immunity have been identified in HIV-infected adults. We have therefore determined the extent and nature of pneumococcal antigen-specific immune recovery following ART. HIV-infected adults were followed up at 3, 6 and 12 months after initiating ART. Nasopharyngeal swabs were cultured to determine carriage rates. Pneumococcal-specific CD4 T-cell immunity was assessed by IFN-γ ELISpot, proliferation assay, CD154 expression and intracellular cytokine assay. S. pneumoniae colonization was detected in 27% (13/48) of HIV-infected patients prior to ART. The rates remained elevated after 12 months ART, 41% (16/39) (p = 0.17) and significantly higher than in HIV-uninfected individuals (HIVneg 14%(4/29); p = 0.0147). CD4+ T-cell proliferative responses to pneumococcal antigens increased significantly to levels comparable with HIV-negative individuals at 12 months ART (p = 0.0799). However, recovery of the pneumococcal-specific CD154 expression was incomplete (p = 0.0015) as were IFN-γ ELISpot responses (p = 0.0040) and polyfunctional CD4+ T-cell responses (TNF-α, IL-2 and IFN-γ expression) (p = 0.0040) to a pneumolysin-deficient mutant strain. Impaired control of pneumococcal colonisation and incomplete restoration of pneumococcal-specific immunity may explain the persistently higher risk of IPD amongst HIV-infected adults on ART. Whether vaccination and prolonged ART can overcome this immunological defect and reduce the high levels of pneumococcal colonisation requires further evaluation

Naturally-Acquired Influenza-Specific CD4+ T-Cell Proliferative Responses Are Impaired in HIV-Infected African Adults

BACKGROUND Seasonal influenza has been associated with greater morbidity and mortality in AIDS patients. Highly-active antiretroviral therapy (HAART) has led to some reduction in influenza-related complications but the nature of naturally-acquired T-cell immunity to influenza virus in an African setting, and how this changes with immune reconstitution following HAART is unknown. We measured influenza-specific CD4(+) T-cell immunity in unimmunized HIV-infected Malawian adults and then investigated immune reconstitution following HAART. METHODS Peripheral blood mononuclear cells were isolated from HIV-infected and HIV-uninfected Malawian adults. CFSE proliferation and CD154 expression flow cytometry-based assays were used to measure influenza-specific CD4(+) T-cell immunity. RESULTS We found lower naturally-acquired proliferative influenza-specific CD4(+) T-cell responses in AIDS patients that was also present in asymptomatic HIV-infected adults with relatively high CD4 counts (>350 cells/µl). Influenza-specific CD4(+) T-cell immune reconstitution in HIV-infected patients on HAART for 12 months was poor despite a marked reduction in viral load and an increase in CD4 count. This poor immune reconstitution was characterised by a low influenza-specific proliferative CD4(+) T-cell response and reduced proportions of CD154-expressing influenza-specific CD4(+) T-cells in peripheral blood. CONCLUSION Our data suggest that asymptomatic HIV-infected adults may also be at risk of influenza-related complications and that HAART alone may not circumvent this risk in AIDS patients. This study highlights the need to identify possible interventions early in HIV infection to reduce the risk of influenza and to intensify influenza surveillance in these susceptible African populations

Influence of HIV and antiretroviral therapy on immunity to pneumococcal T-cell dependent antigens in Malawian adults

Background: Natural immunity to S. pneumoniae is thought to rely on antigen-specific T and B memory that can be rapidly mobilised to mediate microbial clearance at the mucosal surface as well as interrupt multiplication following invasion. HIV infection however increases the risk of invasive pneumococcal disease (IPD) and pneumococcal colonisation, suggesting that natural-acquired pneumococcal immunity is compromised in HIV infection. The aim of this research project was to investigate the effect of underlying HIV infection on naturally-acquired pneumococcal immunity in Malawian adults and the impact of antiretroviral therapy on this immunity. Additionally, the study evaluated the effect of HIV infection on immune memory mounted in response to vaccine protein antigens. Methods: Peripheral blood mononuclear cells obtained from HIV-uninfected and infected Malawian adults were stimulated with pneumococcal concentrated culture supernatants derived from a standard strain D39 wild-type, isogenic mutant strain lacking pneumolysin (Ply-) and diphtheria toxoid. In vitro immune responses to these antigens were assessed by CFSE proliferation, T and B ELISpot, surface expression of CD 154 and cytokine production by intracellular cytokine staining and bio-plex cytokine assays. Additionally, the proportion of T and B cell subsets including naive, memory, senescent and regulatory cells were determined using flow cytometry. Results: Circulating central memory (T CM) and naive (T N) CD4+ T cells were preferentially lost in asymptomatic HIV infection. There was also an over representation of senescent and regulatory T cells in HIV-infected adults. Pneumococcal-specific immune responses were either compromised (IFN-γ effector responses, proliferative and CD 154 expression) or altered (IF -γ/IL-I0) in asymptomatic HIV infection. HIV infection also increased the prevalence of nasopharyngeal colonisation in adults with advanced disease. There was some regeneration of pneumococcal specific CD4+ T cell responses including effector memory responses, proliferative capacity, CD154 pathway and ability to produce simultaneously multiple cytokines following initiation of ART. However, there was no regeneration of antigen-specific memory B cell responses. T and memory B cell responses to protein vaccine antigen (diphtheria toxoid) were compromised and appeared short-lived in HIV-infected persons well-established on ART. Conclusion: The data from this research project showed that HIV infection compromises systemic naturally-acquired pneumococcal immunity and that there is some regeneration of this immunity following initiation of ART. It is not known however whether the re- constituted immunity is long-term and protective. The data also suggests that immune memory to vaccine protein antigens is compromised in HIV-infected adults and possibly short-lived even in individuals stable on ART. These findings have important implications for clinical care of HIV-infected persons on ART and future studies on pneumococcal immunity in the context of HIV infection and therapy.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Influence of HIV and antiretroviral therapy on immunity to pneumococcal T-cell dependent antigens in Malawian adults

Background: Natural immunity to S. pneumoniae is thought to rely on antigen-specific T and B memory that can be rapidly mobilised to mediate microbial clearance at the mucosal surface as well as interrupt multiplication following invasion. HIV infection however increases the risk of invasive pneumococcal disease (IPD) and pneumococcal colonisation, suggesting that natural-acquired pneumococcal immunity is compromised in HIV infection. The aim of this research project was to investigate the effect of underlying HIV infection on naturally-acquired pneumococcal immunity in Malawian adults and the impact of antiretroviral therapy on this immunity. Additionally, the study evaluated the effect of HIV infection on immune memory mounted in response to vaccine protein antigens. Methods: Peripheral blood mononuclear cells obtained from HIV-uninfected and infected Malawian adults were stimulated with pneumococcal concentrated culture supernatants derived from a standard strain D39 wild-type, isogenic mutant strain lacking pneumolysin (Ply-) and diphtheria toxoid. In vitro immune responses to these antigens were assessed by CFSE proliferation, T and B ELISpot, surface expression of CD 154 and cytokine production by intracellular cytokine staining and bio-plex cytokine assays. Additionally, the proportion of T and B cell subsets including naive, memory, senescent and regulatory cells were determined using flow cytometry. Results: Circulating central memory (T CM) and naive (T N) CD4+ T cells were preferentially lost in asymptomatic HIV infection. There was also an over representation of senescent and regulatory T cells in HIV-infected adults. Pneumococcal-specific immune responses were either compromised (IFN-γ effector responses, proliferative and CD 154 expression) or altered (IF -γ/IL-I0) in asymptomatic HIV infection. HIV infection also increased the prevalence of nasopharyngeal colonisation in adults with advanced disease. There was some regeneration of pneumococcal specific CD4+ T cell responses including effector memory responses, proliferative capacity, CD154 pathway and ability to produce simultaneously multiple cytokines following initiation of ART. However, there was no regeneration of antigen-specific memory B cell responses. T and memory B cell responses to protein vaccine antigen (diphtheria toxoid) were compromised and appeared short-lived in HIV-infected persons well-established on ART. Conclusion: The data from this research project showed that HIV infection compromises systemic naturally-acquired pneumococcal immunity and that there is some regeneration of this immunity following initiation of ART. It is not known however whether the re- constituted immunity is long-term and protective. The data also suggests that immune memory to vaccine protein antigens is compromised in HIV-infected adults and possibly short-lived even in individuals stable on ART. These findings have important implications for clinical care of HIV-infected persons on ART and future studies on pneumococcal immunity in the context of HIV infection and therapy.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Alignment of current graduate attributes required of medical graduates of the University of Botswana to the expressed needs of users of the Botswana Health Service

Thesis (MMed)--Stellenbosch University, 2018.ENGLISH SUMMARY : Traditionally, the design of health professions curricula was often guided by traditions, values and priorities of academics. This, however, has led to a mismatch of graduates’ competencies to patient and population needs, prompting a push for curricula design that aligns the goals of professional education with the needs of society. Unsurprisingly, needs assessment for curriculum design should include societal needs (expressed by the communities served and derived from health statistics). Others are perceived needs (identified by students/graduates), observed needs (identified by experts and academics) and organisation needs (identified by invested organisations). This research aimed to determine the extent to which graduate attributes of the University of Botswana Bachelor of Medicine, Bachelor of Surgery (MBBS) programme reflect expressed societal needs. There were two research objectives: Firstly, to determine the expressed needs of users of Botswana health service regarding care received from medical doctors. Secondly, to determine how the MBBS graduate attributes are aligned with the identified expressed needs. There is substantial literature on organisational and observed needs, some data on perceived needs and societal needs derived from health statistics to inform the review of the MBBS curriculum. However, there is no documented evidence of expressed societal needs. This gap in the literature served as the rationale for this study. An interpretivist research paradigm and qualitative approach were adopted. Interviews were conducted using the Critical Incident Technique and twelve participants described their good and bad consultation experiences with medical doctors. A purposive sample was selected through village development committees and patient advocacy groups. Eleven themes were identified as expressed societal needs, which include being respectful, empowering, humble, focused, empathetic, unprejudiced, trustworthy, welcoming, humane, thorough and personal. On the contrary, a number of these identified themes do not align with the defined MBBS graduate attributes, including being focused, unprejudiced, trustworthy, welcoming and thorough. This research, even though limited in the context of this assignment, points to the importance of reconsidering the MBBS graduate attributes with a view to making changes that reflect expressed societal needs.AFRIKAANSE OPSOMMING : Die ontwerp van gesondheidsberoepe-curricula is in die verlede gebaseer op die tradisies, waardes en prioriteite van akademici. Dit het egter gelei tot onvoldoende belyning van die bevoegdhede van gegradueerde ten opsigte van die bevolking se behoeftes. Dit het gevolglik aanleiding gegee dat daar druk uitgeoefen word om curriculumontwikkeling in lyn te bring met die doel van professionele onderwys, naamlik om gemeenskapsbehoeftes aan te spreek. Dit is dus nie onverwags dat ʼn bepaling van gemeenskapsbehoeftes (soos aangedui deur gemeenskappe wat bedien word en wat van gesondheidstatistieke afgelei word) deel moet uitmaak van curriculumontwikkeling nie. Ander behoeftes sluit in soos ervaar is deur studente/graduandi, waargenome behoeftes (soos geïdentifiseer deur kenners en akademici) en organisatoriese behoeftes (soos geïdentifiseer deur belanghebbende organisasies). Die doel van hierdie navorsing was om te bepaal tot watter mate die eienskappe van die gegradueerde, soos vervat in die Universiteit van Botswana se Baccalaureus in Geneeskunde- en Baccalaureus in Chirurgie- (MBBS) program, die uitdruklike behoeftes van die gemeenskap weerspieël. Daar was twee doelwitte vir die navorsing gestel. Eerstens, om die uitdruklike behoeftes van verbruikers van gesondheidsdienste in Botswana te bepaal ten opsigte van die sorg wat ontvang is van medici. Tweedens, om te bepaal tot watter mate die eienskappe van die gegradueerde, soos vervat in die MBBS-program, belyn is met die geïdentifiseerde uitdruklike behoeftes van die gemeenskap. Daar is omvattende literatuur oor organisatoriese en waargenome behoeftes, sommige data oor ervaarde behoeftes en dié van gemeenskappe, soos afgelei is van gesondheidstatistieke, om die kurrikulumhersieningsproses toe te lig. Daar is egter geen dokumentêre bewys van die uitdruklike behoeftes van die gemeenskap nie. Hierdie gaping in die literatuur het as rasionaal gedien vir hierdie studie. ʼn Interpretatiewe navorsingsparadigma en kwalitatiewe benadering is gevolg. Onderhoude is gevoer deur die Kritiese Insident Tegniek te gebruik. Twaalf deelnemers het hul goeie en slegte ervaringe met medici beskryf. ʼn Doelgerigte steekproef is geselekteer deur gebruik te maak van gemeenskapontwikkelingskomitees en ouerkampvegtergroepe. Elf temas is geïdentifiseer as uitdruklike behoeftes van die gemeenskap, wat insluit om respekterend, bemagtigend, nederig, gefokus, empaties, onbevooroordeeld, betrouenswaardig, verwelkomend, menslik, deeglik en persoonlik te wees. Daarteenoor belyn ʼn aantal van hierdie geïdentifiseerde temas nie met die gedefinieerde MBBS eienskappe van die gegradueerde nie. Dit sluit in om gefokus, onbevooroordeeld, betroubaar, verwelkomend en deeglik te wees. Hierdie navorsing, alhoewel beperk gegewe die konteks van die werkstuk, toon die belang aan om die MBBS eienskappe van die gegradueerde te heroorweeg deur veranderinge wat die uitdruklike behoeftes van gemeenskappe weerspieël

Advanced Immune Suppression is Associated With Increased Prevalence of Mixed-Strain Mycobacterium tuberculosis Infections Among Persons at High Risk for Drug-Resistant Tuberculosis in Botswana

We examined factors associated with mixed-strain Mycobacterium tuberculosis infections among patients at high risk for drug-resistant tuberculosis in Botswana. Thirty-seven (10.0%) of 370 patients with tuberculosis had mixed M. tuberculosis infections, based on 24-locus mycobacterial interspersed repetitive unit-variable number of tandem repeats genotyping. In log-binomial regression analysis, age <37 years (adjusted prevalence ratio [PR], 1.92; 95% confidence interval [CI], 1.01-3.57) and prior tuberculosis treatment (adjusted PR, 2.31; 95% CI, 1.09-4.89) were associated with mixed M. tuberculosis infections. Among human immunodeficiency virus-infected patients, prior tuberculosis treatment (adjusted PR, 2.11; 95% CI, 1.04-4.31) and CD4(+) T-cell count of <100 cells/μl (adjusted PR, 10.18; 95% CI, 2.48-41.71) were associated with mixed M. tuberculosis infections. Clinical suspicion of mixed M. tuberculosis infections should be high for patients with advanced immunosuppression and a prior history of tuberculosis treatment

Assessment of prescribing practices at the primary healthcare facilities in Botswana with an emphasis on antibiotics: Findings and implications

Background and Aims: Inappropriate drug prescribing has increased especially in developing countries where systems for monitoring medicine use are not well developed. This increases the rate of antimicrobial resistance. The study aim was to assess the prescribing patterns among urban primary health facilities in Botswana to provide future guidance including developing future quality indicators. Methods: Retrospective data from patients’ records between January – December 2013 in 19 clinics were collected in a cross-sectional study. The WHO/INRUD indicators were used to assess prescribing patterns in the study clinics. Results: Average number of drugs per prescription was 2.8; 78.6% of the prescribed antibiotics were by INN and 96.1% complied with the Botswana Essential Drugs List. Overall rate of antibiotic prescribing was high (42.7%) with 14.7%, 5.9% and 1.3% of prescriptions having two, three and four antibiotics respectively. Systemic antibiotics (J01C) were most (45.1%) commonly prescribed of which amoxicillin accounted for (28.4%) and metronidazole 14.4% of all antibiotic prescriptions. There was low use of co-amoxiclav (0.3% of all antibiotic prescriptions). Third generation cephalosporins and macrolides accounted for 9.8% and 6.2% of antibiotic prescriptions respectively, with no prescribing of fluoroquinolones. The majority of indications (87%) for antibiotic prescriptions were according to ICD classification. Conclusions: While most indications for antibiotic prescriptions were based on signs and symptoms according to ICD, antibiotic prescribing rates were high with some conditions not requiring antibiotics because they are viral infections. There is a need to further improve prescribing practices through induction and training of in-service prescribers. An effective management tool for monitoring antibiotic prescribing practices at PHC facilities should be designed and implemented, including developing robust quality indicators