Cytokine responses to lipopolysaccharide in vivo and ex vivo : Genetic polymorphisms and inter-individual variation

The host response to bacterial invasion requires first the recognition of the presence of pathogens. The presence of a pathogen is detected by binding of pathogen-preserved molecules called 'pathogen-associated molecular patterns' or PAMPs on cell surface receptors known as 'pattern recognition receptors' or PRRs. Lipopolysaccharide (LPS; endotoxin), one of the major outer membrane components of the Gram-negative bacterial cell wall, is an important PAMP. In the last decade the mechanisms by which the host responds to the presence of microbial pathogens on its mucosal surfaces or in the tissues, have been elucidated, most up to their molecular level. With the sequencing of the genome and recognition of the genetic variation within the human population, it became clear this variation is responsible for the inter-individual differences in cytokine release after challenge with microbial products. Such genetically determined variations in cytokine release could be relevant to explain the variability in susceptibility too, and outcome from, sepsis. The thesis focuses on genes that encode for proteins involved in the pathogenesis of sepsis including those involved in the initial recognition of bacterial products such as Toll-like receptors, and cytokines known to mediate the host inflammatory response, such as tumor necrosis factor (TNF)-α, interleukin(IL)-6 and IL-10.LEI Universiteit LeidenZorgOnderzoek Nederland, formerly the Dutch Foundation for Preventive Medicine PraeventieFondsImmunogenetica en immunologie van infectieziekte

Pyridazinediones and amino acid receptors: theoretical studies, design, synthesis, and evaluation of novel analogues

http://www.pharmacol.usyd.edu.au/thesis This thesis is primarily concerned with a class of chemical compounds known as pyridazinediones, being 6-membered aromatic rings containing two adjacent nitrogen atoms (pyridazine), doubly substituted with oxygen. In particular, the work focuses on pyridazine-3,6-diones, derivatives of maleic hydrazide (1). Understanding of the chemistry of these compounds is extended, using theoretical and synthetic techniques. This thesis is also concerned with two very important classes of receptors which bind amino acids in the brain: firstly, the inhibitory GABA receptor, which binds g-aminobutyric acid (GABA) (2) in vivo, and for which muscimol (3) is an agonist of the GABAA subclass; secondly, Excitatory Amino Acid (EAA) receptors, which bind glutamate (4) in vivo, and in particular the AMPA subclass, for which (S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) (5) is an agonist. The connection between pyridazinediones and amino acid receptors is the design, synthesis, and evaluation of structures based on pyridazinediones as potential GABA and EAA receptor ligands. Techniques of theoretical chemistry, molecular modelling, synthetic chemistry, and in vitro pharmacology are used to explore pyridazine-3,6-dione derivatives as ligands

Complicated carriage with methicillin-resistant Staphylococcus aureus: evaluation of the effectiveness of decolonization regimens advised in the Dutch national guideline

Methicillin-resistant Staphylococcus aureus (MRSA) colonization leads to increased infection rates and mortality. Decolonization treatment has been proven to prevent infection and reduce transmission. As the optimal antimicrobial strategy is yet to be established, different regimens are currently prescribed to patients. This study aimed to evaluate the efficacy of the decolonization treatments recommended by the Dutch guideline. A retrospective multicenter cohort study was conducted in five Dutch hospitals. All patients who visited the outpatient clinic because of complicated MRSA carriage between 2014 and 2018 were included. We obtained data on patient characteristics, clinical and microbiological variables relevant for MRSA decolonization, environmental factors, decolonization regimen, and treatment outcome. The primary outcome was defined as three negative MRSA cultures after treatment completion. Outcomes were stratified for the first-line treatment strategies. A total of 131/224 patients were treated with systemic antibiotic agents. Treatment was successful in 111/131 (85%) patients. The success rate was highest in patients treated with doxycycline-rifampin (32/37; 86%), but the difference from any of the other regimens did not reach statistical significance. There was no difference in the success rate of a 7-day treatment compared to that with 10 to 14 days of treatment (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.39 to 253; P= 1.00). Side effects were reported in 27/131 (21%) patients and consisted mainly of mild gastrointestinal complaints. In a multivariable analysis, an immunocompromised status was an independent risk factor for failure at the first treatment attempt (OR, 4.65; 95% CI, 125 to 17.25; P =0.02). The antimicrobial combinations recommended to treat complicated MRSA carriage yielded high success rates. Prolonged treatment did not affect treatment outcome. A randomized trial is needed to resolve whether the most successful regimen in this study (doxycycline plus rifampin) is superior to other combinations.Immunogenetics and cellular immunology of bacterial infectious disease

Immunogenicity and reactogenicity of SARS-CoV-2 vaccines in people living with HIV in the Netherlands: a nationwide prospective cohort study

Background: Vaccines can be less immunogenic in people living with HIV (PLWH), but for SARS-CoV-2 vaccinations this is unknown. In this study we set out to investigate, for the vaccines currently approved in the Netherlands, the immunogenicity and reactogenicity of SARS-CoV-2 vaccinations in PLWH. Methods and findings: We conducted a prospective cohort study to examine the immunogenicity of BNT162b2, mRNA-1273, ChAdOx1-S, and Ad26.COV2.S vaccines in adult PLWH without prior COVID-19, and compared to HIV-negative controls. The primary endpoint was the anti-spike SARS-CoV-2 IgG response after mRNA vaccination. Secondary endpoints included the serological response after vector vaccination, anti-SARS-CoV-2 T-cell response, and reactogenicity. Between 14 February and 7 September 2021, 1,154 PLWH (median age 53 [IQR 44-60] years, 85.5% male) and 440 controls (median age 43 [IQR 33-53] years, 28.6% male) were included in the final analysis. Of the PLWH, 884 received BNT162b2, 100 received mRNA-1273, 150 received ChAdOx1-S, and 20 received Ad26.COV2.S. In the group of PLWH, 99% were on antiretroviral therapy, 97.7% were virally suppressed, and the median CD4+ T-cell count was 710 cells/mu L (IQR 520-913). Of the controls, 247 received mRNA-1273, 94 received BNT162b2, 26 received ChAdOx1-S, and 73 received Ad26.COV2.S. After mRNA vaccination, geometric mean antibody concentration was 1,418 BAU/mL in PLWH (95% CI 1322-1523), and after adjustment for age, sex, and vaccine type, HIV status remained associated with a decreased response (0.607, 95% CI 0.5080.725, p 300 BAU/mL, whilst in PLWH this response rate was 93.6%. In PLWH vaccinated with mRNA-based vaccines, higher antibody responses were predicted by CD4+ Tcell count 250-500 cells/mu L (2.845, 95% CI 1.876-4.314, p 500 cells/mu L (2.936, 95% CI 1.961-4.394, p 50 copies/mL was associated with a reduced response (0.454, 95% CI 0.286-0.720, p = 0.001). Increased IFN-gamma, CD4+ T-cell, and CD8+ T-cell responses were observed after stimulation with SARS-CoV-2 spike peptides in ELISpot and activation-induced marker assays, comparable to controls. Reactogenicity was generally mild, without vaccine-related serious adverse events. Due to the control of vaccine provision by the Dutch National Institute for Public Health and the Environment, there were some differences between vaccine groups in the age, sex, and CD4+ Tcell counts of recipients.Conclusions: After vaccination with BNT162b2 or mRNA-1273, anti-spike SARS-CoV-2 antibody levels were reduced in PLWH compared to HIV-negative controls. To reach and maintain the same serological responses as HIV-negative controls, additional vaccinations are probably required. Author summary: Why was this study done? The efficacy of SARS-CoV-2 vaccines in people living with HIV (PLWH) is not well characterised.HIV has been repeatedly associated with lower immune responses to other vaccines, and this diminished response is strongly correlated with CD4+ T-cell count.The SARS-CoV-2 vaccines BNT162b2, mRNA-1273, ChAdOx1-S, and Ad26.COV2.S showed good protection against severe COVID-19 and hospitalisation in phase III registration trials; however, the number of PLWH in these trials was very limited. What did the researchers do and find?We initiated a nationwide prospective study including 1,154 PLWH and 440 HIV-negative controls.We show that lower antibody levels are seen in PLWH compared to controls after completion of the vaccination schedule, regardless of the vaccine received.All controls receiving an mRNA vaccine had an adequate response, defined as >300 BAU/mL, whilst in PLWH this response rate was 93.6%. In multivariable analyses, having HIV had the largest negative effect on antibody responses following vaccination, more than both age and sex. Following mRNA vaccination, the antibody response was higher in PLWH with CD4+ T-cell counts between 250 and 500 cells/mu L or higher than 500 cells/mu L (both p Immunogenetics and cellular immunology of bacterial infectious disease

Has the Rate of CD4 Cell Count Decline before Initiation of Antiretroviral Therapy Changed over the Course of the Dutch HIV Epidemic among MSM?

Introduction:Studies suggest that the HIV-1 epidemic in the Netherlands may have become more virulent, leading to faster disease progression if untreated. Analysis of CD4 cell count decline before antiretroviral therapy (ART) initiation, a surrogate marker for disease progression, may be hampered by informative censoring as ART initiation is more likely with a steeper CD4 cell count decline.Methods:Development of CD4 cell count from 9 to 48 months after seroconversion was analyzed using a mixed-effects model and 2 models that jointly modeled CD4 cell counts and time to censoring event (start ART

Non-AIDS defining cancers in the D:A:D Study-time trends and predictors of survival : a cohort study

BACKGROUND:Non-AIDS defining cancers (NADC) are an important cause of morbidity and mortality in HIV-positive individuals. Using data from a large international cohort of HIV-positive individuals, we described the incidence of NADC from 2004-2010, and described subsequent mortality and predictors of these.METHODS:Individuals were followed from 1st January 2004/enrolment in study, until the earliest of a new NADC, 1st February 2010, death or six months after the patient's last visit. Incidence rates were estimated for each year of follow-up, overall and stratified by gender, age and mode of HIV acquisition. Cumulative risk of mortality following NADC diagnosis was summarised using Kaplan-Meier methods, with follow-up for these analyses from the date of NADC diagnosis until the patient's death, 1st February 2010 or 6 months after the patient's last visit. Factors associated with mortality following NADC diagnosis were identified using multivariable Cox proportional hazards regression.RESULTS:Over 176,775 person-years (PY), 880 (2.1%) patients developed a new NADC (incidence: 4.98/1000PY [95% confidence interval 4.65, 5.31]). Over a third of these patients (327, 37.2%) had died by 1st February 2010. Time trends for lung cancer, anal cancer and Hodgkin's lymphoma were broadly consistent. Kaplan-Meier cumulative mortality estimates at 1, 3 and 5 years after NADC diagnosis were 28.2% [95% CI 25.1-31.2], 42.0% [38.2-45.8] and 47.3% [42.4-52.2], respectively. Significant predictors of poorer survival after diagnosis of NADC were lung cancer (compared to other cancer types), male gender, non-white ethnicity, and smoking status. Later year of diagnosis and higher CD4 count at NADC diagnosis were associated with improved survival. The incidence of NADC remained stable over the period 2004-2010 in this large observational cohort.CONCLUSIONS:The prognosis after diagnosis of NADC, in particular lung cancer and disseminated cancer, is poor but has improved somewhat over time. Modifiable risk factors, such as smoking and low CD4 counts, were associated with mortality following a diagnosis of NADC

Collaboration in inclusive research: Competencies considered important for people with and without intellectual disabilities

With inclusive research being an emerging field of interest, there is growing recognition that establishing collaborative relationships between researchers with and without ID entails specific demands. However, since studies on collaboration in inclusive research merely provide individual reports on experiences and challenges in one particular research project, building a shared knowledge base of concrete competencies considered important for those involved merits attention. This study contributes to a shared knowledge base in asking people with and without ID with (experiential) knowledge of inclusive research for competencies they consider important in collaborating in inclusive research in general, that is, without reference to a specific research project they participated in. Researchers with and without ID, coaches, policy makers, and teachers involved in the education of people with ID participated in this study. Data were collected from a focus group, individual interviews, and expert meetings. Qualitative analysis was carried out immediately after each moment of data collection, providing the use of increasing insights in each consecutive phase of data collection. Participants describe that establishing collaborative relationships between researchers with and without ID in inclusive research requires the commitment of both parties. They mentioned concrete competencies they consider important for people with and without ID to collaborate in inclusive research in the categories: building a mutual relationship, communicating, achieving a collaboration in which everyone involved can contribute, being aware of skills and developmental needs, and being aware of impact. Clearly, describing competencies for people with and without ID is not intended to exclude anyone who does not possess these competencies from collaboration in inclusive research. However to avoid “tokenism,” this study might contribute to effective participation of people with ID in inclusive research in providing concrete competencies considered important in collaboration