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2.
HIV Med ; 25(6): 700-710, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38361216

ABSTRACT

OBJECTIVES: We aimed to assess the extent of integration of non-communicable disease (NCD) assessment and management in HIV clinics across Europe. METHODS: A structured electronic questionnaire with 41 multiple-choice and rating-scale questions assessing NCD assessment and management was sent to 88 HIV clinics across the WHO European Region during March-May 2023. One response per clinic was collected. RESULTS: In all, 51 clinics from 34 countries with >100 000 people with HIV under regular follow-up responded. Thirty-seven clinics (72.6%) reported shared NCD care responsibility with the general practitioner. Systematic assessment for NCDs and integration of NCD management were common overall [median agreement 80%, interquartile range (IQR): 55-95%; and 70%, IQR: 50-88%, respectively] but were lowest in central eastern and eastern Europe. Chronic kidney disease (median agreement 96%, IQR: 85-100%) and metabolic disorders (90%, IQR: 75-100%) were regularly assessed, while mental health (72%, IQR: 63-85%) and pulmonary diseases (52%, IQR: 40-75%) were less systematically assessed. Some essential diagnostic tests such as glycated haemoglobin (HbA1c) for diabetes (n = 38/51, 74.5%), proteinuria for kidney disease (n = 30/51, 58.8%) and spirometry for lung disease (n = 11/51, 21.6%) were only employed by a proportion of clinics. The most frequent barriers for integrating NCD care were the lack of healthcare workers (n = 17/51, 33.3%) and lack of time during outpatient visits (n = 12/51, 23.5%). CONCLUSION: Most HIV clinics in Europe systematically assess and manage NCDs. People with HIV appear to be screened more frequently than the general population at the same age. There are, however, larger gaps among eastern European clinics in general and for clinics in all regions related to mental health, pulmonary diseases and the employment of some essential diagnostic tests.


Subject(s)
HIV Infections , Noncommunicable Diseases , Humans , Noncommunicable Diseases/therapy , Noncommunicable Diseases/epidemiology , HIV Infections/diagnosis , HIV Infections/therapy , HIV Infections/complications , HIV Infections/epidemiology , Europe , Surveys and Questionnaires , World Health Organization , Female , Male , Adult , Renal Insufficiency, Chronic/therapy , Renal Insufficiency, Chronic/diagnosis , Renal Insufficiency, Chronic/epidemiology
3.
Int J Equity Health ; 22(1): 205, 2023 10 05.
Article in English | MEDLINE | ID: mdl-37794428

ABSTRACT

BACKGROUND: Sars-CoV-2, the causative agent of COVID-19, has led to more than 226,000 deaths in the UK and multiple risk factors for mortality including age, sex and deprivation have been identified. This study aimed to identify which individual indicators of the Scottish Index of Multiple Deprivation (SIMD), an area-based deprivation index, were predictive of mortality. METHODS: This was a prospective cohort study of anonymised electronic health records of 710 consecutive patients hospitalised with Covid-19 disease between March and June 2020 in the Lothian Region of Southeast Scotland. Data sources included automatically extracted data from national electronic platforms and manually extracted data from individual admission records. Exposure variables of interest were SIMD quintiles and 12 indicators of deprivation deemed clinically relevant selected from the SIMD. Our primary outcome was mortality. Age and sex adjusted univariable and multivariable analyses were used to determine measures of association between exposures of interest and the primary outcome. RESULTS: After adjusting for age and sex, we found an increased risk of mortality in the more deprived SIMD quintiles 1 and 3 (OR 1.75, CI 0.99-3.08, p = 0.053 and OR 2.17, CI 1.22-3.86, p = 0.009, respectively), but this association was not upheld in our multivariable model containing age, sex, Performance Status and clinical parameters of severity at admission. Of the 12 pre-selected indicators of deprivation, two were associated with greater mortality in our multivariable analysis: income deprivation rate categorised by quartile (Q4 (most deprived): 2.11 (1.20-3.77) p = 0.011)) and greater than expected hospitalisations due to alcohol per SIMD data zone (1.96 (1.28-3.00) p = 0.002)). CONCLUSIONS: SIMD as an aggregate measure of deprivation was not predictive of mortality in our cohort when other exposure measures were accounted for. However, we identified a two-fold increased risk of mortality in patients residing in areas with greater income-deprivation and/or number of hospitalisations due to alcohol. In areas where aggregate measures fail to capture pockets of deprivation, exploring the impact of specific SIMD indicators may be helpful in targeting resources to residents at risk of poorer outcomes from Covid-19.


Subject(s)
COVID-19 , Humans , Cohort Studies , Socioeconomic Factors , Prospective Studies , SARS-CoV-2 , Scotland/epidemiology
4.
J R Coll Physicians Edinb ; 52(3): 204-212, 2022 09.
Article in English | MEDLINE | ID: mdl-36369813

ABSTRACT

BACKGROUND: COVID-19 mortality risk factors have been established in large cohort studies; long-term mortality outcomes are less documented. METHODS: We performed multivariable logistic regression to identify factors associated with in-patient mortality and intensive care unit (ICU) admission in symptomatic COVID-19 patients admitted to hospitals in South-East Scotland from 1st March to 30th June 2020. One-year mortality was reviewed. RESULTS: Of 726 patients (median age 72; interquartile range: 58-83 years, 55% male), 104 (14%) required ICU admission and 199 (27%) died in hospital. A further 64 died between discharge and 30th June 2021 (36% overall 1-year mortality). Stepwise logistic regression identified age >79 (odds ratio (OR), 4.77 (95% confidence interval (CI), 1.96-12.75)), male sex (OR, 1.83 (95% CI, 1.21-2.80)) and higher European Cooperative Oncology Group/World Health Organization performance status as associated with higher mortality risk. DISCUSSION: Poor functional baseline was the predominant independent risk factor for mortality in COVID-19. More than one-third of individuals had died by 1 year following admission.


Subject(s)
COVID-19 , Humans , Male , Aged , Female , SARS-CoV-2 , Intensive Care Units , Hospitalization , Risk Factors , Hospital Mortality , Retrospective Studies
5.
EBioMedicine ; 76: 103856, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35152152

ABSTRACT

BACKGROUND: Many repurposed drugs have progressed rapidly to Phase 2 and 3 trials in COVID19 without characterisation of Pharmacokinetics /Pharmacodynamics including safety data. One such drug is nafamostat mesylate. METHODS: We present the findings of a phase Ib/IIa open label, platform randomised controlled trial of intravenous nafamostat in hospitalised patients with confirmed COVID-19 pneumonitis. Patients were assigned randomly to standard of care (SoC), nafamostat or an alternative therapy. Nafamostat was administered as an intravenous infusion at a dose of 0.2 mg/kg/h for a maximum of seven days. The analysis population included those who received any dose of the trial drug and all patients randomised to SoC. The primary outcomes of our trial were the safety and tolerability of intravenous nafamostat as an add on therapy for patients hospitalised with COVID-19 pneumonitis. FINDINGS: Data is reported from 42 patients, 21 of which were randomly assigned to receive intravenous nafamostat. 86% of nafamostat-treated patients experienced at least one AE compared to 57% of the SoC group. The nafamostat group were significantly more likely to experience at least one AE (posterior mean odds ratio 5.17, 95% credible interval (CI) 1.10 - 26.05) and developed significantly higher plasma creatinine levels (posterior mean difference 10.57 micromol/L, 95% CI 2.43-18.92). An average longer hospital stay was observed in nafamostat patients, alongside a lower rate of oxygen free days (rate ratio 0.55-95% CI 0.31-0.99, respectively). There were no other statistically significant differences in endpoints between nafamostat and SoC. PK data demonstrated that intravenous nafamostat was rapidly broken down to inactive metabolites. We observed no significant anticoagulant effects in thromboelastometry. INTERPRETATION: In hospitalised patients with COVID-19, we did not observe evidence of anti-inflammatory, anticoagulant or antiviral activity with intravenous nafamostat, and there were additional adverse events. FUNDING: DEFINE was funded by LifeArc (an independent medical research charity) under the STOPCOVID award to the University of Edinburgh. We also thank the Oxford University COVID-19 Research Response Fund (BRD00230).


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Benzamidines/therapeutic use , COVID-19 Drug Treatment , Guanidines/therapeutic use , Administration, Intravenous , Adult , Aged , Aged, 80 and over , Anti-Inflammatory Agents, Non-Steroidal/pharmacokinetics , Benzamidines/adverse effects , Benzamidines/pharmacokinetics , Biomarkers/blood , Biomarkers/metabolism , COVID-19/mortality , COVID-19/virology , Drug Administration Schedule , Female , Guanidines/adverse effects , Guanidines/pharmacokinetics , Half-Life , Humans , Immunophenotyping , Kaplan-Meier Estimate , Male , Middle Aged , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Treatment Outcome , Viral Load
6.
BMJ Open ; 11(12): e054442, 2021 12 15.
Article in English | MEDLINE | ID: mdl-34911721

ABSTRACT

INTRODUCTION: COVID-19 is a new viral-induced pneumonia caused by infection with a novel coronavirus, SARS-CoV-2. At present, there are few proven effective treatments. This early-phase experimental medicine protocol describes an overarching and adaptive trial designed to provide safety data in patients with COVID-19, pharmacokinetic (PK)/pharmacodynamic (PD) information and exploratory biological surrogates of efficacy, which may support further development and deployment of candidate therapies in larger scale trials of patients positive for COVID-19. METHODS AND ANALYSIS: Define is an ongoing exploratory multicentre-platform, open-label, randomised study. Patients positive for COVID-19 will be recruited from the following cohorts: (a) community cases; (b) hospitalised patients with evidence of COVID-19 pneumonitis; and (c) hospitalised patients requiring assisted ventilation. The cohort recruited from will be dependent on the experimental therapy, its route of administration and mechanism of action. Randomisation will be computer generated in a 1:1:n ratio. Twenty patients will be recruited per arm for the initial two arms. This is permitted to change as per the experimental therapy. The primary statistical analyses are concerned with the safety of candidate agents as add-on therapy to standard of care in patients with COVID-19. Secondary analysis will assess the following variables during treatment period: (1) the response of key exploratory biomarkers; (2) change in WHO ordinal scale and National Early Warning Score 2 (NEWS2) score; (3) oxygen requirements; (4) viral load; (5) duration of hospital stay; (6) PK/PD; and (7) changes in key coagulation pathways. ETHICS AND DISSEMINATION: The Define trial platform and its initial two treatment and standard of care arms have received a favourable ethical opinion from Scotland A Research Ethics Committee (REC) (20/SS/0066), notice of acceptance from The Medicines and Healthcare Products Regulatory Agency (MHRA) (EudraCT 2020-002230-32) and approval from the relevant National Health Service (NHS) Research and Development (R&D) departments (NHS Lothian and NHS Greater Glasgow and Clyde). Appropriate processes are in place in order to be able to consent adults with and without capacity while following the necessary COVID-19 safe procedures. Patients without capacity could be recruited via a legal representative. Witnessed electronic consent of participants or their legal representatives following consent discussions was established. The results of each study arm will be submitted for publication in a peer-reviewed journal as soon as the treatment arm has finished recruitment, data input is complete and any outstanding patient safety follow-ups have been completed. Depending on the results of these or future arms, data will be shared with larger clinical trial networks, including the Randomised Evaluation of COVID-19 Therapy trial (RECOVERY), and to other partners for rapid roll-out in larger patient cohorts. TRIAL REGISTRATION NUMBER: ISRCTN14212905, NCT04473053.


Subject(s)
Biomedical Research , COVID-19 , Clinical Trials, Phase I as Topic , Clinical Trials, Phase II as Topic , Electronics , Humans , Multicenter Studies as Topic , Randomized Controlled Trials as Topic , State Medicine
7.
Wellcome Open Res ; 6: 142, 2021.
Article in English | MEDLINE | ID: mdl-34381874

ABSTRACT

Higher academic institutions in the UK need to drive improvements in equity, diversity, and inclusion (EDI) through sustainable practical interventions. A broad view of inclusivity is based on an intersectional approach that considers race, geographical location, caring responsibilities, disability, neurodiversity, religion, and LGBTQIA+ identities. We describe the establishment of a diverse stakeholder group to develop practical grass-roots recommendations through which improvements can be advanced. We have developed a manifesto for change, comprising six domains through which academic institutions can drive progress through setting short, medium, and long-term priorities. Interventions will yield rewards in recruitment and retention of a diverse talent pool, leading to enhanced impact and output.

8.
BMC Infect Dis ; 21(1): 318, 2021 Apr 06.
Article in English | MEDLINE | ID: mdl-33823800

ABSTRACT

BACKGROUND: Accurate diagnosis in patients with suspected coronavirus disease 2019 (COVID-19) is essential to guide treatment and limit spread of the virus. The combined nasal and throat swab is used widely, but its diagnostic performance is uncertain. METHODS: In a prospective, multi-centre, cohort study conducted in secondary and tertiary care hospitals in Scotland, we evaluated the combined nasal and throat swab with reverse transcriptase-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in consecutive patients admitted to hospital with suspected COVID-19. Diagnostic performance of the index and serial tests was evaluated for a primary outcome of confirmed or probable COVID-19, and a secondary outcome of confirmed COVID-19 on serial testing. The diagnosis was adjudicated by a panel, who recorded clinical, laboratory and radiological features blinded to the test results. RESULTS: We enrolled 1368 consecutive patients (median age 68 [interquartile range, IQR 53-80] years, 47% women) who underwent a total of 3822 tests (median 2 [IQR 1-3] tests per patient). The primary outcome occurred in 36% (496/1368), of whom 65% (323/496) and 35% (173/496) had confirmed and probable COVID-19, respectively. The index test was positive in 255/496 (51%) patients with the primary outcome, giving a sensitivity and specificity of 51.4% (95% confidence interval [CI] 48.8 to 54.1%) and 99.5% (95% CI 99.0 to 99.8%). Sensitivity increased in those undergoing 2, 3 or 4 tests to 60.1% (95% CI 56.7 to 63.4%), 68.3% (95% CI 64.0 to 72.3%) and 77.6% (95% CI 72.7 to 81.9%), respectively. The sensitivity of the index test was 78.9% (95% CI 74.4 to 83.2%) for the secondary outcome of confirmed COVID-19 on serial testing. CONCLUSIONS: In patients admitted to hospital, a single combined nasal and throat swab with RT-PCR for SARS-CoV-2 has excellent specificity, but limited diagnostic sensitivity for COVID-19. Diagnostic performance is significantly improved by repeated testing.


Subject(s)
COVID-19 Nucleic Acid Testing , COVID-19/diagnosis , Nose/virology , Pharynx/virology , Aged , Aged, 80 and over , Female , Hospitalization , Hospitals , Humans , Male , Middle Aged , Prospective Studies , Reverse Transcriptase Polymerase Chain Reaction , Scotland , Sensitivity and Specificity
9.
Int J Equity Health ; 19(1): 150, 2020 09 01.
Article in English | MEDLINE | ID: mdl-32873291

ABSTRACT

STUDY AIM: To assess whether Outpatient Parenteral Antimicrobial Therapy (OPAT) is provided equitably across gender and social groups in a tertiary care setting. BACKGROUND: OPAT is a widely used and growing approach in high income countries to early discharge or admission avoidance for patients requiring intravenous antimicrobials. There is however a risk that equitable access to healthcare could be eroded unintentionally by expansion of outpatient or ambulatory approaches such as this. Anecdotal evidence in our service, and from published studies, have identified a gender and social group equity gap in outpatient services. METHODS: Service data on inpatient cellulitis episodes over a seven-year period were matched to OPAT referral data to create a retrospective cross-sectional linked dataset. All individuals admitted from 2012 to 2017 inclusive for a primary diagnosis of cellulitis were included: 6295 admissions of 4944 individuals. Demographics, number of co-morbidities, length of hospital stay, number of admissions, distance from OPAT unit and Scottish Index of Multiple Deprivation (SIMD; as a metric of deprivation) were recorded. Adjusted odds of a referral to OPAT across SIMD quintiles and for females compared to males were calculated using multiple logistic regression. RESULTS: Inequitable access to OPAT was identified. Deprivation was negatively associated with likelihood of OPAT referral. Inpatients from the most affluent SIMD quintile were more than twice as likely to have received an OPAT referral compared to those resident in the most deprived quintile (adjusted OR 2.08, 95% CI: 1.60-2.71, p <  0.0001). Women were almost a third less likely to receive an OPAT referral than men (adjusted OR 0.69, 95% CI: 0.58 to 0.82, p <  0.001). Results were adjusted for age, number of co-morbidities, admissions, length of stay, distance from nearest OPAT unit, time since first admission, deprivation and gender. CONCLUSIONS: OPAT services and other ambulatory care programmes should routinely evaluate the equity of their service provision and consider how they can reduce any identified imbalance. It is a critical responsibility of service planning to ensure an inequitable system does not develop, with those least able to access ambulatory care dispossessed of the associated benefits.


Subject(s)
Ambulatory Care , Anti-Bacterial Agents/administration & dosage , Cellulitis/therapy , Healthcare Disparities , Infusions, Parenteral/methods , Referral and Consultation , Adolescent , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Cellulitis/drug therapy , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Odds Ratio , Outpatients , Retrospective Studies , Sex Factors , Young Adult
10.
Clin Med (Lond) ; 20(3): 290-291, 2020 05.
Article in English | MEDLINE | ID: mdl-32414716

ABSTRACT

The growing epidemic of SARS-CoV-2 challenges healthcare resources globally and mandates innovation. We describe our novel drive-through coronavirus testing which we used for testing of possible cases in the contain phase of UK response and are now using for healthcare worker testing. We found that this system was pragmatic, cost-efficient and favourable for patients. It is easily modifiable for use in future infectious disease outbreaks.


Subject(s)
Betacoronavirus , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Automobile Driving , COVID-19 , COVID-19 Testing , Humans , Pandemics , Practice Guidelines as Topic , SARS-CoV-2
11.
Clin Infect Dis ; 71(10): e710-e713, 2020 12 17.
Article in English | MEDLINE | ID: mdl-32266388

ABSTRACT

Among 200 patients developing hospital-acquired pneumonia (HAP) outside the intensive care unit, 61% were treated empirically without broad-spectrum Gram-negative coverage, with clinical cure in 69.7%. Lower disease severity markers (systemic inflammatory response syndrome, hypoxia, tachypnoea, neutrophilia) and the absence of diabetes mellitus and prior doxycycline treatment (but not the time to HAP onset) identified patients not requiring broad-spectrum Gram-negative coverage.


Subject(s)
Anti-Infective Agents , Cross Infection , Healthcare-Associated Pneumonia , Pneumonia , Anti-Bacterial Agents/therapeutic use , Cross Infection/drug therapy , Healthcare-Associated Pneumonia/drug therapy , Healthcare-Associated Pneumonia/epidemiology , Hospitals , Humans , Pneumonia/drug therapy
12.
Euro Surveill ; 25(12)2020 03.
Article in English | MEDLINE | ID: mdl-32234116

ABSTRACT

In response to the outbreak of COVID-19, we set up a team to carry out sampling in the community. This enabled individuals to remain in self-isolation in their own homes and to prevent healthcare settings and services from being overwhelmed by admissions for sampling of suspected cases. There is evidence that this is a cost effective, safe and necessary service to complement COVID-19 testing in hospitals.


Subject(s)
Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus/isolation & purification , Disease Outbreaks/prevention & control , Mass Screening/methods , Pneumonia, Viral/prevention & control , Asymptomatic Diseases , Betacoronavirus , COVID-19 , COVID-19 Testing , Community Health Services/organization & administration , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Coronavirus Infections/virology , Humans , Pandemics , Patient Isolation , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Public Health Practice , Quarantine , SARS-CoV-2 , Scotland/epidemiology , Time Factors
13.
J Infect ; 81(1): 147-178, 2020 07.
Article in English | MEDLINE | ID: mdl-32205138

ABSTRACT

Since its identification in December 2019, SARS-CoV-2 has infected 125,048 persons globally with cases identified in 118 countries across all continents. We report on the Scottish index case of SARS-CoV-2 infection, the virus causing COVID-19.


Subject(s)
Coronavirus Infections , Coronavirus , Pneumonia, Viral , Severe acute respiratory syndrome-related coronavirus , Betacoronavirus , COVID-19 , Humans , Pandemics , SARS-CoV-2 , Scotland , United Kingdom
15.
JAC Antimicrob Resist ; 1(2): dlz042, 2019 Sep.
Article in English | MEDLINE | ID: mdl-34222916

ABSTRACT

BACKGROUND: As meropenem is a restricted antimicrobial, lessons learned from its real-life usage will be applicable to antimicrobial stewardship (AMS) more generally. OBJECTIVES: To retrospectively evaluate meropenem usage at our institution to identify targets for AMS interventions. METHODS: Patients receiving meropenem documented with an 'alert antimicrobial' form at two tertiary care UK hospitals were identified retrospectively. Clinical records and microbiology results were reviewed. RESULTS: A total of 107 adult inpatients receiving meropenem were identified. This was first-line in 47% and escalation therapy in 53%. Source control was required in 28% of cases after escalation, for predictable reasons. Those ultimately requiring source control had received more prior antimicrobial agents than those who did not (P = 0.03). Meropenem was rationalized in 24% of cases (after median 4 days). Positive microbiology enabled rationalization (OR 12.3, 95% CI 2.7-55.5, P = 0.001) but rates of appropriate sampling varied. In cases with positive microbiology where meropenem was not rationalized, continuation was retrospectively considered clinically and microbiologically necessary in 8/40 cases (0/17 empirical first-line usage). Rationalization was more likely when meropenem susceptibility was not released on the microbiology report (OR 5.2, 95% CI 1.3-20.2, P = 0.02). Input from an infection specialist was associated with a reduced duration of meropenem therapy (P < 0.0001). Early review by an infection specialist has the potential to further facilitate rationalization. CONCLUSIONS: In real-life clinical practice, core aspects of infection management remain tractable targets for AMS interventions: microbiological sampling, source control and infection specialist input. Further targets include supporting rationalization to less familiar carbapenem-sparing antimicrobials, restricting first-line meropenem usage and selectively reporting meropenem susceptibility.

16.
Med Teach ; 39(9): 981-986, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28552022

ABSTRACT

CONTEXT: The emerging global-health paradigm requires medical teaching to be continuously redefined and updated; to this end, transnational approaches should be encouraged and medical training harmonized. Infectious diseases (ID) teaching in the current context of emerging infections, fast-increasing bacterial resistance and large-scale human migration, was chosen to develop a common international course. OBJECTIVE: We report the successful implementation of a joint European undergraduate course aiming to (i) develop a common ID core curriculum among European medical schools; (ii) promote mobility among teachers and students (iii) promote international cooperation among European teachers. METHODS: The course was built around teachers' mobility. It was delivered in English by a team of European medical educators from Paris Descartes University, Università Cattolica del Sacro Cuore in Rome and the University of Edinburgh to groups of 25-30 undergraduate medical students at each university. Partner Institutions officially recognized the course as substitutive of or additive to the regular curriculum. RESULTS: The course has been running for 3 years and received excellent satisfaction scores by students and staff as regards to scientific content, pedagogy and international exchanges. CONCLUSION: This cooperative approach demonstrates the feasibility of a harmonized European undergraduate medical education, having ID as a test experiment for future developments.


Subject(s)
Communicable Diseases , Curriculum , Education, Medical, Undergraduate/methods , Global Health/education , Students, Medical , Teaching , Communicable Diseases, Emerging , Drug Resistance, Bacterial , Education, Medical , Europe , Humans , Public Health , Schools, Medical , Transients and Migrants
18.
J Clin Invest ; 122(9): 3227-38, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22850879

ABSTRACT

Plasmodium falciparum is the major cause of malaria globally and is transmitted by mosquitoes. During parasitic development, P. falciparum-infected erythrocytes (P. falciparum-IEs) express multiple polymorphic proteins known as variant surface antigens (VSAs), including the P. falciparum erythrocyte membrane protein 1 (PfEMP1). VSA-specific antibodies are associated with protection from symptomatic and severe malaria. However, the importance of the different VSA targets of immunity to malaria remains unclear, which has impeded an understanding of malaria immunity and vaccine development. In this study, we developed assays using transgenic P. falciparum with modified PfEMP1 expression to quantify serum antibodies to VSAs among individuals exposed to malaria. We found that the majority of the human antibody response to the IE targets PfEMP1. Furthermore, our longitudinal studies showed that individuals with PfEMP1-specific antibodies had a significantly reduced risk of developing symptomatic malaria, whereas antibodies to other surface antigens were not associated with protective immunity. Using assays that measure antibody-mediated phagocytosis of IEs, an important mechanism in parasite clearance, we identified PfEMP1 as the major target of these functional antibodies. Taken together, these data demonstrate that PfEMP1 is a key target of humoral immunity. These findings advance our understanding of the targets and mediators of human immunity to malaria and have major implications for malaria vaccine development.


Subject(s)
Antibodies, Protozoan/blood , Antigens, Protozoan/genetics , Disease Resistance , Erythrocytes/parasitology , Malaria, Falciparum/immunology , Plasmodium falciparum/immunology , Protozoan Proteins/genetics , Adolescent , Adult , Antigens, Protozoan/metabolism , Child , Child, Preschool , Disease-Free Survival , Endemic Diseases , Genetic Engineering , Humans , Infant , Kaplan-Meier Estimate , Kenya/epidemiology , Malaria, Falciparum/blood , Malaria, Falciparum/epidemiology , Middle Aged , Organisms, Genetically Modified , Phagocytosis , Plasmodium falciparum/genetics , Plasmodium falciparum/metabolism , Promoter Regions, Genetic , Protozoan Proteins/metabolism , Statistics, Nonparametric , Young Adult
19.
Infect Immun ; 77(5): 1917-23, 2009 May.
Article in English | MEDLINE | ID: mdl-19223480

ABSTRACT

In studies of immunity to malaria, the absence of febrile malaria is commonly considered evidence of "protection." However, apparent "protection" may be due to a lack of exposure to infective mosquito bites or due to immunity. We studied a cohort that was given curative antimalarials before monitoring began and documented newly acquired asymptomatic parasitemia and febrile malaria episodes during 3 months of surveillance. With increasing age, there was a shift away from febrile malaria to acquiring asymptomatic parasitemia, with no change in the overall incidence of infection. Antibodies to the infected red cell surface were associated with acquiring asymptomatic infection rather than febrile malaria or remaining uninfected. Bed net use was associated with remaining uninfected rather than acquiring asymptomatic infection or febrile malaria. These observations suggest that most uninfected children were unexposed rather than "immune." Had they been immune, we would have expected the proportion of uninfected children to rise with age and that the uninfected children would have been distinguished from children with febrile malaria by the protective antibody response. We show that removing the less exposed children from conventional analyses clarifies the effects of immunity, transmission intensity, bed nets, and age. Observational studies and vaccine trials will have increased power if they differentiate between unexposed and immune children.


Subject(s)
Fever/etiology , Fever/prevention & control , Malaria/immunology , Malaria/physiopathology , Age Factors , Antibodies, Protozoan/blood , Antimalarials/therapeutic use , Child , Child, Preschool , Cohort Studies , Humans , Incidence , Infant , Parasitemia/immunology
20.
Malar J ; 7: 155, 2008 Aug 16.
Article in English | MEDLINE | ID: mdl-18706102

ABSTRACT

BACKGROUND: Antibodies targeting variant antigens expressed on the surface of Plasmodium falciparum infected erythrocytes have been associated with protection from clinical malaria. The precise target for these antibodies is unknown. The best characterized and most likely target is the erythrocyte surface-expressed variant protein family Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). METHODS: Using recombinant proteins corresponding to five domains of the expressed A4 var gene, A4 PfEMP1, the naturally occurring antibody response was assessed, by ELISA, to each domain in serum samples obtained from individuals resident in two communities of differing malaria transmission intensity on the Kenyan coast. Using flow cytometry, the correlation in individual responses to each domain with responses to intact A4-infected erythrocytes expressing A4 PfEMP1 on their surface as well as responses to two alternative parasite clones and one clinical isolate was assessed. RESULTS: Marked variability in the prevalence of responses between each domain and between each transmission area was observed, as wasa strong correlation between age and reactivity with some but not all domains. Individual responses to each domain varied strikingly, with some individuals showing reactivity to all domains and others with no reactivity to any, this was apparent at all age groups. Evidence for possible cross-reactivity in responses to the domain DBL4gamma was found. CONCLUSION: Individuals acquire antibodies to surface expressed domains of a highly variant protein. The finding of potential cross-reactivity in responses to one of these domains is an important initial finding in the consideration of potential vaccine targets.


Subject(s)
Antibodies, Protozoan/blood , Malaria, Falciparum/immunology , Plasmodium falciparum/immunology , Protozoan Proteins/immunology , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Animals , Child , Child, Preschool , Cross Reactions , Enzyme-Linked Immunosorbent Assay , Erythrocytes/immunology , Erythrocytes/parasitology , Flow Cytometry , Geography , Humans , Infant , Kenya , Middle Aged , Recombinant Proteins/genetics
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