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Quantifying individual nociceptive sensitivity to optimise analgesic trials in infants
AbstractDespite the high burden of pain experienced by hospitalised infants there are few analgesics with proven efficacy. Testing analgesics in infants is experimentally and ethically challenging and minimising the number of infants required to demonstrate efficacy is essential. EEG-derived measures of noxious-evoked brain activity can be used to assess analgesic efficacy, however, as variability exists in infant’s responses to painful procedures, large sample sizes are often required. Here we present a novel experimental paradigm to account for individual differences in baseline nociceptive sensitivity which can be used to improve the design of analgesic trials in infants. The paradigm is developed and tested across four studies using clinical, experimental and simulated data (99 infants). We provide evidence of the efficacy of both gentle brushing and paracetamol, substantiating the need for randomised controlled trials of these interventions. This work provides an important step towards safe, cost-effective clinical trials of analgesics in infants.
PvDBPII elicits multiple antibody-mediated mechanisms that reduce growth in a Plasmodium vivax challenge trial.
The receptor-binding domain, region II, of the Plasmodium vivax Duffy binding protein (PvDBPII) binds the Duffy antigen on the reticulocyte surface to mediate invasion. A heterologous vaccine challenge trial recently showed that a delayed dosing regimen with recombinant PvDBPII SalI variant formulated with adjuvant Matrix-MTM reduced the in vivo parasite multiplication rate (PMR) in immunized volunteers challenged with the Thai P. vivax isolate PvW1. Here, we describe extensive analysis of the polyfunctional antibody responses elicited by PvDBPII immunization and identify immune correlates for PMR reduction. A classification algorithm identified antibody features that significantly contribute to PMR reduction. These included antibody titre, receptor-binding inhibitory titre, dissociation constant of the PvDBPII-antibody interaction, complement C1q and Fc gamma receptor binding and specific IgG subclasses. These data suggest that multiple immune mechanisms elicited by PvDBPII immunization are likely to be associated with protection and the immune correlates identified could guide the development of an effective vaccine for P. vivax malaria. Importantly, all the polyfunctional antibody features that correlated with protection cross-reacted with both PvDBPII SalI and PvW1 variants, suggesting that immunization with PvDBPII should protect against diverse P. vivax isolates.
Boosting with adjuvanted SCB-2019 elicits superior Fcγ-receptor engagement driven by IgG3 to SARS-CoV-2 spike.
With the continued emergence of variants of concern, the global threat of COVID-19 persists, particularly in low- and middle-income countries with limited vaccine access. Protein-based vaccines, such as SCB-2019, can be produced on a large scale at a low cost while antigen design and adjuvant use can modulate efficacy and safety. While effective humoral immunity against SARS-CoV-2 variants has been shown to depend on both neutralization and Fc-mediated immunity, data on the effectiveness of protein-based vaccines with enhanced Fc-mediated immunity is limited. Here, we assess the humoral profile, including antibody isotypes, subclasses, and Fc receptor binding generated by a boosting with a recombinant trimer-tag protein vaccine SCB-2019. Individuals who were primed with 2 doses of the ChAdOx1 vaccine were equally divided into 4 groups and boosted with following formulations: Group 1: 9 μg SCB-2019 and Alhydrogel; Group 2: 9 μg SCB-2019, CpG 1018, and Alhydrogel; Group 3: 30 μg SCB-2019, CpG 1018, and Alhydrogel; Group 4: ChAdOx1. Group 3 showed enhanced antibody FcγR binding against wild-type and variants compared to Groups 1 and 2, showing a dose-dependent enhancement of immunity conferred by the SCB-2019 vaccine. Moreover, from day 15 after vaccination, Group 3 exhibited higher IgG3 and FcγR binding across variants of concerns, including Omicron and its subvariants, compared to the ChAdOx1-boosted individuals. Overall, this highlights the potential of SCB-2019 as a cost-efficient boosting regimen effective across variants of concerns.
Protocol for the challenge non-typhoidal Salmonella (CHANTS) study: a first-in-human, in-patient, double-blind, randomised, safety and dose-escalation controlled human infection model in the UK.
INTRODUCTION: Invasive non-typhoidal Salmonella (iNTS) serovars are a major cause of community-acquired bloodstream infections in sub-Saharan Africa (SSA). In this setting, Salmonella enterica serovar Typhimurium accounts for two-thirds of infections and is associated with an estimated case fatality rate of 15%-20%. Several iNTS vaccine candidates are in early-stage assessment which-if found effective-would provide a valuable public health tool to reduce iNTS disease burden. The CHANTS study aims to develop a first-in-human Salmonella Typhimurium controlled human infection model, which can act as a platform for future vaccine evaluation, in addition to providing novel insights into iNTS disease pathogenesis. METHODS AND ANALYSIS: This double-blind, safety and dose-escalation study will randomise 40-80 healthy UK participants aged 18-50 to receive oral challenge with one of two strains of S. Typhimurium belonging to the ST19 (strain 4/74) or ST313 (strain D23580) lineages. 4/74 is a global strain often associated with diarrhoeal illness predominantly in high-income settings, while D23580 is an archetypal strain representing invasive disease-causing isolates found in SSA. The primary objective is to determine the minimum infectious dose (colony-forming unit) required for 60%-75% of participants to develop clinical or microbiological features of systemic salmonellosis. Secondary endpoints are to describe and compare the clinical, microbiological and immunological responses following challenge. Dose escalation or de-escalation will be undertaken by continual-reassessment methodology and limited within prespecified safety thresholds. Exploratory objectives are to describe mechanisms of iNTS virulence, identify putative immune correlates of protection and describe host-pathogen interactions in response to infection. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the NHS Health Research Authority (London-Fulham Research Ethics Committee 21/PR/0051; IRAS Project ID 301659). The study findings will be disseminated in international peer-reviewed journals and presented at national/international stakeholder meetings. Study outcome summaries will be provided to both funders and participants. TRIAL REGISTRATION NUMBER: NCT05870150.
Intravenous immunoglobulin treatment in childhood encephalitis (IgNiTE): a randomised controlled trial.
OBJECTIVE: To investigate whether intravenous immunoglobulin (IVIG) improves neurological outcomes in children with encephalitis when administered early in the illness. DESIGN: Phase 3b multicentre, double-blind, randomised placebo-controlled trial. SETTING: Twenty-one hospitals in the UK. PARTICIPANTS: Children aged 6 months to 16 years with a diagnosis of acute or subacute encephalitis, with a planned sample size of 308. INTERVENTION: Two doses (1 g/kg/dose) of either IVIG or matching placebo given 24-36 hours apart, in addition to standard treatment. MAIN OUTCOME MEASURE: The primary outcome was a 'good recovery' at 12 months after randomisation, defined as a score of≤2 on the Paediatric Glasgow Outcome Score Extended. SECONDARY OUTCOME MEASURES: The secondary outcomes were clinical, neurological, neuroimaging and neuropsychological results, identification of the proportion of children with immune-mediated encephalitis, and IVIG safety data. RESULTS: 18 participants were recruited from 12 hospitals and randomised to receive either IVIG (n=10) or placebo (n=8) between 23 December 2015 and 26 September 2017. The study was terminated early following withdrawal of funding due to slower than anticipated recruitment, and therefore did not reach the predetermined sample size required to achieve the primary study objective; thus, the results are descriptive. At 12 months after randomisation, 9 of the 18 participants (IVIG n=5/10 (50%), placebo n=4/8 (50%)) made a good recovery and 5 participants (IVIG n=3/10 (30%), placebo n=2/8 (25%)) made a poor recovery. Three participants (IVIG n=1/10 (10%), placebo n=2/8 (25%)) had a new diagnosis of epilepsy during the study period. Two participants were found to have specific autoantibodies associated with autoimmune encephalitis. No serious adverse events were reported in participants receiving IVIG. CONCLUSIONS: The IgNiTE (ImmunoglobuliN in the Treatment of Encephalitis) study findings support existing evidence of poor neurological outcomes in children with encephalitis. However, the study was halted prematurely and was therefore underpowered to evaluate the effect of early IVIG treatment compared with placebo in childhood encephalitis. TRIAL REGISTRATION NUMBER: Clinical Trials.gov NCT02308982; ICRCTN registry ISRCTN15791925.
The Human GP130 Cytokine Receptor and Its Expression-an Atlas and Functional Taxonomy of Genetic Variants.
Genetic variants in IL6ST encoding the shared cytokine receptor for the IL-6 cytokine family GP130 have been associated with a diverse number of clinical phenotypes and disorders. We provide a molecular classification for 59 reported rare IL6ST pathogenic or likely pathogenic variants and additional polymorphisms. Based on loss- or gain-of-function, cytokine selectivity, mono- and biallelic associations, and variable cellular mosaicism, we grade six classes of IL6ST variants and explore the potential for additional variants. We classify variants according to the American College of Medical Genetics and Genomics criteria. Loss-of-function variants with (i) biallelic complete loss of GP130 function that presents with extended Stüve-Wiedemann Syndrome; (ii) autosomal recessive hyper-IgE syndrome (HIES) caused by biallelic; and (iii) autosomal dominant HIES caused by monoallelic IL6ST variants both causing selective IL-6 and IL-11 cytokine loss-of-function defects; (iv) a biallelic cytokine-specific variant that exclusively impairs IL-11 signaling, associated with craniosynostosis and tooth abnormalities; (v) somatic monoallelic mosaic constitutively active gain-of-function variants in hepatocytes that present with inflammatory hepatocellular adenoma; and (vi) mosaic constitutively active gain-of-function variants in hematopoietic and non-hematopoietic cells that are associated with an immune dysregulation syndrome. In addition to Mendelian IL6ST coding variants, there are common non-coding cis-acting variants that modify gene expression, which are associated with an increased risk of complex immune-mediated disorders and trans-acting variants that affect GP130 protein function. Our taxonomy highlights IL6ST as a gene with particularly strong functional and phenotypic diversity due to the combinatorial biology of the IL-6 cytokine family and predicts additional genotype-phenotype associations.
Antibody responses to Influenza vaccination are diminished in patients with inflammatory bowel disease on infliximab or tofacitinib.
BACKGROUND AND AIMS: We sought to determine whether six commonly used immunosuppressive regimens were associated with lower antibody responses after seasonal influenza vaccination in patients with IBD. METHODS: We conducted a prospective study including 213 IBD patients and 53 healthy controls; 165 who had received seasonal influenza vaccine and 101 who had not. IBD medications included infliximab, thiopurines, infliximab and thiopurine combination therapy, ustekinumab, vedolizumab or tofacitinib. The primary outcome was antibody responses against influenza/A H3N2 and A/H1N1, compared to controls, adjusting for age, prior vaccination and interval between vaccination and sampling. RESULTS: Lower antibody responses against influenza A/H3N2 were observed in patients on infliximab (Geometric Mean Ratio 0.35 [95% CI 0.20-0.60], p=0.0002), combination of infliximab and thiopurine therapy (0.46 [0.27-0.79], p=0.0050) and tofacitinib (0.28 [0.14-0.57], p=0.0005) compared to controls. Lower antibody responses against A/H1N1 were observed in patients on infliximab (0.29 [0.15-0.56], p=0.0003), combination of infliximab and thiopurine therapy (0.34 [0.17-0.66], p=0.0016), thiopurine monotherapy (0.46 [0.24-0.87], p=0.017) and tofacitinib (0.23 [0.10-0.56], p=0.0013). Ustekinumab and vedolizumab were not associated with reduced antibody responses against A/H3N2 or A/H1N1. Vaccination in the previous year was associated with higher antibody responses to A/H3N2. Vaccine-induced anti-SARS-CoV-2 antibody concentration weakly correlated with antibodies against H3N2 (r=0.27; p=0.0004) and H1N1 (r=0.33; p<0.0001). CONCLUSIONS: Vaccination in both the 2020-2021 and 2021-2022 seasons was associated with significantly higher antibody responses to influenza/A than no vaccination or vaccination in 2021-2022 alone. Infliximab and tofacitinib are associated with lower binding antibody responses to Influenza/A, similar to COVID-19 vaccine-induced antibody responses.
Tuberculosis of the central nervous system
Central nervous system (CNS) tuberculosis represents around 1% of all cases of tuberculosis. Yet, despite its relative rarity, it is an important clinical problem because it kills or maims a higher proportion of patients than any other form of tuberculosis. CNS tuberculosis takes two major forms: tuberculous meningitis (TBM) and cerebral tuberculoma. TBM causes death or severe neurological sequelae in 50% of sufferers and is the most dangerous form of tuberculosis. TBM causes progressive confusion and coma and is almost always fatal if left untreated. It should be considered a medical emergency, mandating rapid diagnosis and treatment. Cerebral tuberculomas, in contrast, are not immediately life-threatening. They are well-defined, granulomatous, space-occupying lesions, which can occur anywhere in the CNS, including the spinal cord. Their clinical manifestations depend upon their anatomical location, but an isolated seizure is the most common presentation. Tuberculomas are not immediately life-threatening unless they rupture and release bacteria into the subarachnoid space to cause TBM.