Evaluation of QuantiFERON SARS-CoV-2 interferon-γ release assay following SARS-CoV-2 infection and vaccination

T cells are important in preventing severe disease from SARS-CoV-2, but scalable and field-adaptable alternatives to expert T-cell assays are needed. The interferon-gamma release assay QuantiFERON platform was developed to detect T-cell responses to SARS-CoV-2 from whole blood with relatively basic equipment and flexibility of processing timelines. Forty-eight participants with different infection and vaccination backgrounds were recruited. Whole blood samples were analysed using the QuantiFERON SARS-CoV-2 assay in parallel with the well-established 'Protective Immunity from T Cells in Healthcare workers' (PITCH) ELISpot, which can evaluate spike-specific T-cell responses. The primary aims of this cross-sectional observational cohort study were to establish if the QuantiFERON SARS-Co-V-2 assay could discern differences between specified groups and to assess the sensitivity of the assay compared with the PITCH ELISpot. The QuantiFERON SARS-CoV-2 distinguished acutely infected individuals (12-21 days post positive PCR) from naïve individuals (P < 0.0001) with 100% sensitivity and specificity for SARS-CoV-2 T cells, whilst the PITCH ELISpot had reduced sensitivity (62.5%) for the acute infection group. Sensitivity with QuantiFERON for previous infection was 12.5% (172-444 days post positive test) and was inferior to the PITCH ELISpot (75%). Although the QuantiFERON assay could discern differences between unvaccinated and vaccinated individuals (55-166 days since second vaccination), the latter also had reduced sensitivity (44.4%) compared to the PITCH ELISpot (66.6%). The QuantiFERON SARS-CoV-2 assay showed potential as a T- cell evaluation tool soon after SARS-CoV-2 infection but has lower sensitivity for use in reliable evaluation of vaccination or more distant infection.

Evolution of long-term vaccine-induced and hybrid immunity in healthcare workers after different COVID-19 vaccine regimens

BACKGROUND

Both infection and vaccination, alone or in combination, generate antibody and T cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the maintenance of such responses-and hence protection from disease-requires careful characterization. In a large prospective study of UK healthcare workers (HCWs) (Protective Immunity from T Cells in Healthcare Workers [PITCH], within the larger SARS-CoV-2 Immunity and Reinfection Evaluation [SIREN] study), we previously observed that prior infection strongly affected subsequent cellular and humoral immunity induced after long and short dosing intervals of BNT162b2 (Pfizer/BioNTech) vaccination.

METHODS

Here, we report longer follow-up of 684 HCWs in this cohort over 6-9 months following two doses of BNT162b2 or AZD1222 (Oxford/AstraZeneca) vaccination and up to 6 months following a subsequent mRNA booster vaccination.

FINDINGS

We make three observations: first, the dynamics of humoral and cellular responses differ; binding and neutralizing antibodies declined, whereas T and memory B cell responses were maintained after the second vaccine dose. Second, vaccine boosting restored immunoglobulin (Ig) G levels; broadened neutralizing activity against variants of concern, including Omicron BA.1, BA.2, and BA.5; and boosted T cell responses above the 6-month level after dose 2. Third, prior infection maintained its impact driving larger and broader T cell responses compared with never-infected people, a feature maintained until 6 months after the third dose.

CONCLUSIONS

Broadly cross-reactive T cell responses are well maintained over time-especially in those with combined vaccine and infection-induced immunity ("hybrid" immunity)-and may contribute to continued protection against severe disease.

FUNDING

Department for Health and Social Care, Medical Research Council.

P12.03.B Ascorbate alters the hypoxic pathway in glioblastoma cellsin vitro and associates with improved patient survival

Background

Glioblastomas are highly aggressive and hypoxic tumours. This environment activates the hypoxic pathway, driving glioma progression and treatment resistance. The hypoxic pathway is regulated by the hypoxia inducible factor (HIF) hydroxylases, which require oxygen as a substrate. Under normoxic conditions, the HIF hydroxylases are active, causing degradation and inhibition of HIF transcription factors. Under hypoxia, the activity of the hydroxylases reduces and HIF accumulates, activating the hypoxic response. HIF hydroxylases also require ascorbate as a cofactor for optimal function. The brain has one of the highest ascorbate levels in the human body, yet data on ascorbate levels in gliomas is scarce. Cellular ascorbate uptake occurs through solute carrier family 23 member 2 (SLC23A2). My aim is to understand the relationship between ascorbate, SLC23A2 and the hypoxic pathway in brain cancer using both in vitro cell culture and clinical samples.

Material and Methods

Ascorbate uptake was measured in human glioblastoma cell lines (T98G, U251MG, U87MG; ATCC) using reverse phase high performance liquid chromatography (HPLC-ECD). CRISPR-Cas was designed to knock-out SLC23A2. Clinical glioblastoma samples (n=37) and follow-up data were provided by the Cancer Society Tissue Bank and University of Otago Dunedin. Ethics and informed consent were obtained (H19/163, MEC/08/02/016). Ascorbate levels, measured by HPLC-ECD, and HIF-1α and downstream targets were measured using Western blotting or ELISA. A HIF score was calculated from HIF-1α and downstream target protein levels to estimate hypoxic pathway activity.

Results

In this study we have shown that T98G and U251 cells accumulate up to 15 nmol ascorbate/106 cells when exposed to 500 µM ascorbate for up to 24 hours, compared to U87MG cells with up to 3 nmol ascorbate/106 cells. Cancer Cell Line Encyclopaedia data shows that T98G and U251MG cells express higher levels of SLC23A2 compared to U87MG cells, aligning with our results. Clinical glioblastoma tissue contained a median of 7.6 µg ascorbate/100 mg tissue. Patients survival was significantly longer with above, vs below, median tumour ascorbate levels (Gehan-Breslow-Wilcoxon p = 0.027). The HIF score was negatively correlated with tumour ascorbate levels (Pearson r -0.327, p = 0.048). Patients with higher HIF-score had significantly shorter survival time compared to those with a lower HIF score (Gehan-Breslow-Wilcoxon p = 0.005).

Conclusion

Ascorbate uptake in glioblastoma cells varies between cell lines and appears reliant on the level of SLC23A2. Higher ascorbate content in clinical glioblastoma samples was associated with reduced hypoxic pathway activity and longer patient survival. Ongoing work, using SLC23A2 CRISPR-Cas knock-out cells, is investigating the effect of disrupting ascorbate uptake on hypoxic pathway signalling in glioblastoma cells.

P12.06.A Relationship between ascorbate and DNA methylation markers in clinical glioma tumours

Background

Members of the 2-oxoglutarate-dependent dioxygenase (OGDD) enzyme family play an important role in gliomas as they regulate epigenetic modifications and response to hypoxia. The OGDDs require 2-OG and O2 as substrates, and ferrous iron and ascorbate as cofactors. Both hypoxia and aberrant DNA methylation are prognostic indicators for gliomas. The ten-eleven translocase (TET) DNA demethylases are OGDDs that convert 5-methyl cytosine (5mC) to 5-hydroxymethylcytosine (5hmC), with 5hmC levels related to better prognosis. Despite this, there is limited data on the OGDD enzymes and their substrates/cofactors in glioma tissues. Our previous study showed an association between ascorbate content and markers of the hypoxic response in glioblastoma tissue. Here we determine whether there is an association between ascorbate and DNA methylation in glioma. In addition, we assess whether methylation of the methylguanine-DNA methyltransferase (DNA repair enzyme MGMT) promoter is associated with ascorbate content.

Materials and methods

Frozen clinical glioma samples from 37 patients (n=11 WHO grade I-III, n=26 glioblastoma) were obtained from the Cancer Society Tissue Bank (Ethics approval H19/163). Isocitrate dehydrogenase 1 (IDH1) mutation status was determined by sequencing. Samples were processed on dry ice in liquid nitrogen and analysed for ascorbate (high-performance liquid chromatography), global DNA methylation (mass spectrometry) and MGMT promoter analyses (methylation specific PCR).

Results

Many grade I-III tumours were IDH1 R132H mutant (6/11), and most glioblastomas were not (2/26). Glioblastoma had significantly lower ascorbate content than grade I-III tumours (p=0.026). Glioblastoma also had lower global 5hmC levels (p=0.0013). IDH1 R132H tumours tended to have a lower ascorbate content (p=0.09). Ascorbate and 5hmC levels were directly correlated (Spearman r= 0.466, p=0.004). However, cytosine and 5mC showed no association with grade or ascorbate. MGMT promoter methylation status was not associated with global methylation or ascorbate content (p=0.97, p=0.96, respectively).

Conclusion

Our data suggests that ascorbate supports TET activity in clinical glioma. It also appears that site-specific (promoter) methylation was not affected by ascorbate availability. These findings may have clinical implications, as higher 5hmC levels are associated with improved outcome, whilst continued MGMT suppression suggests chemotherapy responsiveness. However, evidence that raising tumour ascorbate leads to increased 5hmC levels, or an associated improvement in survival, requires intervention trials.

Impaired humoral and cellular response to primary COVID-19 vaccination in patients less than 2 years after allogeneic bone marrow transplant

Allogeneic haematopoietic stem cell transplant (HSCT) recipients remain at high risk of adverse outcomes from coronavirus disease 2019 (COVID-19) and emerging variants. The optimal prophylactic vaccine strategy for this cohort is not defined. T cell-mediated immunity is a critical component of graft-versus-tumour effect and in determining vaccine immunogenicity. Using validated anti-spike (S) immunoglobulin G (IgG) and S-specific interferon-gamma enzyme-linked immunospot (IFNγ-ELIspot) assays we analysed response to a two-dose vaccination schedule (either BNT162b2 or ChAdOx1) in 33 HSCT recipients at ≤2 years from transplant, alongside vaccine-matched healthy controls (HCs). After two vaccines, infection-naïve HSCT recipients had a significantly lower rate of seroconversion compared to infection-naïve HCs (25/32 HSCT vs. 39/39 HCs no responders) and had lower S-specific T-cell responses. The HSCT recipients who received BNT162b2 had a higher rate of seroconversion compared to ChAdOx1 (89% vs. 74%) and significantly higher anti-S IgG titres (p = 0.022). S-specific T-cell responses were seen after one vaccine in HCs and HSCT recipients. However, two vaccines enhanced S-specific T-cell responses in HCs but not in the majority of HSCT recipients. These data demonstrate limited immunogenicity of two-dose vaccination strategies in HSCT recipients, bolstering evidence of the need for additional boosters and/or alternative prophylactic measures in this group.

Comparison of two T-cell assays to evaluate T-cell responses to SARS-CoV-2 following vaccination in naïve and convalescent healthcare workers

T-cell responses to SARS-CoV-2 following infection and vaccination are less characterized than antibody responses, due to a more complex experimental pathway. We measured T-cell responses in 108 healthcare workers (HCWs) using the commercialized Oxford Immunotec T-SPOT Discovery SARS-CoV-2 assay service (OI T-SPOT) and the PITCH ELISpot protocol established for academic research settings. Both assays detected T-cell responses to SARS-CoV-2 spike, membrane, and nucleocapsid proteins. Responses were significantly lower when reported by OI T-SPOT than by PITCH ELISpot. Four weeks after two doses of either Pfizer/BioNTech BNT162b or ChAdOx1 nCoV-19 AZD1222 vaccine, the responder rate was 63% for OI T-SPOT Panels 1 + 2 (peptides representing SARS-CoV-2 spike protein excluding regions present in seasonal coronaviruses), 69% for OI T-SPOT Panel 14 (peptides representing the entire SARS-CoV-2 spike), and 94% for the PITCH ELISpot total spike. The two OI T-SPOT panels correlated strongly with each other showing that either readout quantifies spike-specific T-cell responses, although the correlation between the OI T-SPOT panels and the PITCH ELISpot total spike was moderate. The standardization, relative scalability, and longer interval between blood acquisition and processing are advantages of the commercial OI T-SPOT assay. However, the OI T-SPOT assay measures T-cell responses at a significantly lower magnitude compared to the PITCH ELISpot assay, detecting T-cell responses in a lower proportion of vaccinees. This has implications for the reporting of low-level T-cell responses that may be observed in patient populations and for the assessment of T-cell durability after vaccination.

POS1444 FLT1 AND EPHB2 ARE NOVEL GENETIC MARKERS ASSOCIATED WITH PANCREATITIS IN PATIENTS TAKING AZATHIOPRINE FOR IMMUNE-MEDIATED CONDITIONS: INTEGRATING GENOME- AND TRANSCRIPTOME-WIDE ASSOCIATION STUDIES

Background

Azathioprine (AZA) is a thiopurine immunosuppressant medication used to treat a variety of immune-mediated diseases. Unfortunately, its use is limited by adverse effects. Pancreatitis, a potentially severe, life-threatening side effect is independent of dose and necessitates AZA discontinuation given the high risk of recurrent pancreatitis with continued use or re-challenge. The mechanisms driving pancreatitis are unclear. While classic thiopurine-induced acute pancreatitis (TIAP) has been associated with HLA haplotypes, most patients taking AZA and presenting with pancreatitis do not fulfill the stringent criteria for TIAP.

Objectives

To identify genetic risk factors for pancreatitis in patients taking azathioprine for immune-mediated conditions.

Methods

Using a biobank linked to electronic health records (EHR) from a tertiary center, we identified new users of AZA. Patients were excluded if the primary indication for AZA was organ transplant or if there was a history of pancreatitis prior to AZA use. The analysis was restricted to patients with EHR-reported race as White due to insufficient case counts for the non-White group. We then identified patients with amylase or lipase values that exceeded twice the upper limit of normal (“>2x ULN”) or with ICD-9/ICD-10 codes for acute pancreatitis. Each record was manually reviewed to confirm the timing of AZA use in relation to laboratory derangements or ICD coding, as well as to further classify patients into three increasingly strict, but not exclusive categories: 1) pancreatic injury (amylase or lipase >2x ULN); 2) acute pancreatitis1, or 3) TIAP2. We completed genotyping with Illumina Infinium Expanded Multi-Ethnic Genotyping Array plus custom content data, employed Michigan Imputation servers for genetic imputation, and used PrediXcan (GTEx v8) to impute gene expression. We then conducted genome-wide association and transcriptome-wide association studies (GWAS, TWAS). Acknowledging the relatively small overall cohort, and possible imbalance of cases vs controls, we used the Firth logistic regression method, which is a penalized likelihood-based method.

Results

We studied 2127 AZA users (35.4% male; mean 44.5+/-17.2 years). The median AZA dose was 100mg/day (IQR: 50-125mg/day). Rheumatologic conditions (56.9%) and inflammatory bowel disease (40.4%) comprised the most common primary indications for AZA. Pancreatic injury, pancreatitis, and TIAP were diagnosed in 42 (2.0%), 16 (0.8%), and 9 (0.4%) patients, respectively. GWAS identified several significantly associated genes, many with overlapping TWAS findings in the pancreas and liver (Figure 1). From these, the two protein-encoding genes Fms Related Receptor Tyrosine Kinase-1 (FLT1) and Ephrin type-B receptor-2 (EPHB2) overlapped in two or more pancreatitis phenotypes in the TWAS and GWAS, respectively. EPHB2 was associated with a 8.6-fold (P=1.84 x 10-8) and a 31.4-fold (P=2.87x 10-8) higher likelihood of pancreatic injury and TIAP, respectively.

Figure 1.

Conclusion

FLT1—a gene that encodes a receptor tyrosine kinase and is a member of the vascular endothelial growth factor receptor (VEGFR) family—and EPHB2—a gene that encodes a member of the Eph receptor family, which is the largest subgroup of the receptor tyrosine kinase family—are novel genetic markers associated with pancreatitis in patients taking AZA. VEGF can potentiate inflammation and the pancreas microenvironment is known to promote VEGF expression, which has been linked to pancreatic cancer development; anti-VEGF treatments have been investigated both for mitigating inflammation and also anti-pancreatic cancer treatment. Future studies validating our findings in AZA-induced pancreatitis are warranted.

References

[1]Crockett et al. Gastroenterology (2018). 154(4):1096-1101.

[2]Heap et al. Nature Genetics (2014). 46:1131-1134

Disclosure of Interests

Shailja Shah Consultant of: ad hoc consultant for Phathom pharmaceuticals, Tyler Reese: None declared, Jacy Zanussi: None declared, Alyson Dickson: None declared, Laura Daniel: None declared, Ran Tao: None declared, Tyne Miller-Fleming: None declared, Peter Straub: None declared, Adriana Hung: None declared, Puran Nepal: None declared, Wei-Qi Wei: None declared, Elizabeth Phillips: None declared, Nancy Cox: None declared, Charles M. Stein: None declared, QiPeng Feng: None declared, Cecilia P. Chung: None declared

Measuring the temporal dynamics of inter-personal neural entrainment in continuous child-adult EEG hyperscanning data

Current approaches to analysing EEG hyperscanning data in the developmental literature typically consider interpersonal entrainment between interacting physiological systems as a time-invariant property. This approach obscures crucial information about how entrainment between interacting systems is established and maintained over time. Here, we describe methods, and present computational algorithms, that will allow researchers to address this gap in the literature. We focus on how two different approaches to measuring entrainment, namely concurrent (e.g., power correlations, phase locking) and sequential (e.g., Granger causality) measures, can be applied to three aspects of the brain signal: amplitude, power, and phase. We guide the reader through worked examples using simulated data on how to leverage these methods to measure changes in interbrain entrainment. For each, we aim to provide a detailed explanation of the interpretation and application of these analyses when studying neural entrainment during early social interactions.

Ethical considerations in the design and conduct of a cluster-randomised mycotoxin mitigation trial in Tanzania

Aflatoxins are fungal metabolites that commonly contaminate staple food crops in tropical regions. Acute aflatoxin consumption in very high concentration causes aflatoxicosis and acute liver failure, while chronic, moderate levels of intake cause hepatocellular carcinoma. The effects of frequent moderate- to high-level exposure during infancy, however, is less clearly understood. Half a billion people in low- and middle-income countries continue to be exposed to aflatoxins through dietary consumption, in part because of lack of enforcement of regulatory limits and few feasible long-term mitigation options in these settings. Several epidemiologic studies have shown an association between aflatoxin exposure in infants and young children and growth failure, but strong experimental evidence is lacking. The Mycotoxin Mitigation Trial conducted in Tanzania was a cluster-randomised trial to assess the effect of a reduced aflatoxin diet on linear growth. Prior to the design and implementation of this trial, a group of multi-disciplinary and multi-national scientists reviewed literature in biomedical, public health, environmental health ethics. In this paper we outline the most salient ethical questions and dilemmas in the potential conduct of such a study and describe the ethical precedents and principles that informed our decision-making processes and ultimate study protocol.

Immunogenicity of standard and extended dosing intervals of BNT162b2 mRNA vaccine

Extension of the interval between vaccine doses for the BNT162b2 mRNA vaccine was introduced in the United Kingdom to accelerate population coverage with a single dose. At this time, trial data were lacking, and we addressed this in a study of United Kingdom healthcare workers. The first vaccine dose induced protection from infection from the circulating alpha (B.1.1.7) variant over several weeks. In a substudy of 589 individuals, we show that this single dose induces severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibody (NAb) responses and a sustained B and T cell response to the spike protein. NAb levels were higher after the extended dosing interval (6-14 weeks) compared with the conventional 3- to 4-week regimen, accompanied by enrichment of CD4+ T cells expressing interleukin-2 (IL-2). Prior SARS-CoV-2 infection amplified and accelerated the response. These data on dynamic cellular and humoral responses indicate that extension of the dosing interval is an effective immunogenic protocol.

Risk factors associated with heel pressure ulcer development in adult population: A systematic literature review

AIMS

The main aim of this systematic literature review was to identify risk factors for development of heel pressure ulcers and quantify their effect.

BACKGROUND

Pressure ulcers remain one of the key patient safety challenges across all health care settings and heels are the second most common site for developing pressure ulcers after the sacrum.

DESIGN

Quantitative systematic review.

METHODS

Data sources: Electronic databases were searched for studies published between 1809 to March 2020 using keywords, Medical Subject Headings, and other index terms, as well as combinations of these terms and appropriate synonyms.

STUDY ELIGIBILITY CRITERIA

Previous systematic literature reviews, cohort, case control and cross-sectional studies investigating risk factors for developing heel pressure ulcers. Only articles published in English were reviewed with no restrictions on date of publication.

PARTICIPANTS

patients aged 18 years and above in any care setting. Study selection, data extraction, risk of bias and quality assessment were completed by two independent reviewers. Disagreements were resolved by discussion.

RESULTS

Thirteen studies met the eligibility criteria and several potential risk factors were identified. However, eligible studies were mainly moderate to low quality except for three high quality studies.

CONCLUSIONS

There is a paucity of high quality evidence to identify risk factors associated with heel pressure ulcer development. Immobility, diabetes, vascular disease, impaired nutrition, perfusion issues, mechanical ventilation, surgery, and Braden subscales were identified as potential risk factors for developing heel pressure ulcers however, further well-designed studies are required to elucidate these factors. Other risk factors may also exist and require further investigation.

PROSPERO ID

PROSPERO International prospective register of systematic reviews: CRD42017071459.

Automatic classification of ICA components from infant EEG using MARA

Automated systems for identifying and removing non-neural ICA components are growing in popularity among EEG researchers of adult populations. Infant EEG data differs in many ways from adult EEG data, but there exists almost no specific system for automated classification of source components from paediatric populations. Here, we adapt one of the most popular systems for adult ICA component classification for use with infant EEG data. Our adapted classifier significantly outperformed the original adult classifier on samples of naturalistic free play EEG data recorded from 10 to 12-month-old infants, achieving agreement rates with the manual classification of over 75% across two validation studies (n = 44, n = 25). Additionally, we examined both classifiers’ ability to remove stereotyped ocular artifact from a basic visual processing ERP dataset compared to manual ICA data cleaning. Here, the new classifier performed on level with expert manual cleaning and was again significantly better than the adult classifier at removing artifact whilst retaining a greater amount of genuine neural signal operationalised through comparing ERP activations in time and space. Our new system (iMARA) offers developmental EEG researchers a flexible tool for automatic identification and removal of artifactual ICA components.

•

Currently, few tools are available for ICA based data correction that are designed around infant EEG.

•

ICA correction is necessary for naturalistic paradigms when movement artifacts covary with cognitive processes.

•

We present a system for automated ICA classification designed around infant EEG data.

•

This system offers increased performance compared to systems of automatic ICA classification designed around adult EEG.

P16.11 Vitamin C levels and the hypoxic pathway in human glioma tissues

BACKGROUND

Gliomas are the most common brain cancer and survival is poor, with 11–15 months for high-grade glioblastoma patients, despite treatment. Gliomas are hypoxic tumours, which increases with tumour grade. Under hypoxia, the transcription factor hypoxia inducible factor-1 (HIF) accumulates and upregulates expression of genes involved in tumour development and progression. HIF-1 levels and activity are controlled by HIF hydroxylases which target HIF-1α for degradation and prevent co-activation. HIF hydroxylases are part of the 2-oxoglutarate (2-OG)-dependent dioxygenase enzyme family, that require 2-OG and oxygen as substrates and ascorbate and iron as co-factors. The role of ascorbate in regulating the hypoxic pathway in cancer is of interest, with previous research showing reduced HIF pathway activity with increasing tumour ascorbate levels. Brain tissue has one of the highest ascorbate levels in the body, and is one of the last to become depleted under deficiency, indicating an important role for ascorbate in this tissue. One previous study has analysed ascorbate levels in 11 human glioblastoma patients, and showed lower ascorbate in tumour tissue compared to normal brain tissue. There have been no studies investigating the relationship between ascorbate levels and the hypoxic pathway in human glioma tissues.

MATERIAL AND METHODS

Human glioma tissues (n = 39), obtained from the Cancer Society Tissue Bank Christchurch (ethics approval H19/163), were processed for ascorbate and hypoxic pathway proteins (HIF-1α, CA-IX, BNIP3, HKII, GLUT1 and VEGF). Ascorbate levels were quantified by HPLC-ED, and proteins were measured by Western blotting and ELISA. Spearman’s correlations were used to identify relationships between ascorbate and HIF pathway proteins.

RESULTS

Of the samples, 64% were GBM. Ascorbate was significantly lower in GBM compared to low-grade gliomas (p = 0.04). VEGF was significantly higher in GBM compared to astrocytomas (p = 0.01). Increased tumour ascorbate was associated with lower VEGF and CA-IX proteins. HIF-1α and BNIP3 protein were positively associated, and VEGF was positively associated with HKII and CA-IX. VEGF inversely associated with BNIP3, and CA-IX inversely associated with HKII. The hypoxic pathway score (calculated from protein levels of members of the hypoxic pathway) was reduced in tumours with higher ascorbate but this did not reach significance (p = 0.2).

CONCLUSION

This is the first study to show that ascorbate levels were reduced in high-grade gliomas compared to low-grade. Some members of the hypoxic pathway were associated with ascorbate levels. The overall hypoxic pathway score did not significantly correlate with ascorbate and increased numbers of samples are required to confirm any associations. Other variables, such as IDH-1 mutation status of the tumours may affect the correlation and will be analysed next.

P04.04 Optimizing dasatinib for glioblastoma treatment

BACKGROUND

Glioblastoma is the most common primary malignancy of the central nervous system with a dismal prognosis, even with surgical and chemoradiotherapy. Expression profiling studies classify IDH-wildtype Glioblastoma into three subtypes: Proneural (PN), mesenchymal (MES) and classical (CL). A promising target to inhibit in Glioblastoma is the non-receptor tyrosine kinase and proto-oncogene SRC. After robust pre-clinical results, SRC inhibitors like dasatinib did not improve survival of Glioblastoma patients after recurrence in clinical trials.

MATERIAL AND METHODS

Consolidating efforts to personalize cancer therapy, we use in silico analyses backed by in vitro and in vivo experiments on Glioblastoma stem-like cells (GSCs) derived from primary patient tumors to present a novel stratification strategy for dasatinib therapy in glioblastoma. To further tackle dasatinib resistance in GSCs, a pooled shRNA library against 5000 genes was combined with dasatinib to identify genes whose knockdown sensitizes GSCs to dasatinib. This was integrated with proteomics and phosphoproteomics data of dasatinib inhibited GSCs.

RESULTS

We found MES tumors with high expression of SERPINH1 to be sensitive to dasatinib inhibition, compared to the CL and PN subtypes. Interestingly, SRC phosphorylation status did not predict the efficacy of dasatinib inhibition. Computational analyses integrating data from the loss-of-function dropout viability screen and proteomics/phosphoproteomics using a novel modification of the SamNet algorithm identified Wee1, a tyrosine kinase involved in cell-cycle signaling, as a potential combination inhibition target with dasatinib. Further validation experiments showed a robust synergistic effect through combination of dasatinib and the wee1 inhibitor, MK-1775 in PN GSCs.

CONCLUSION

This study highlights strategies to optimize dasatinib treatment in different glioblastoma subtypes. While the stratification of patients harboring mesenchymal glioblastoma with SERPINH1 overexpression could provide an option in this particular subtype, combining dasatinib or other SRC inhibitors with Wee1 inhibitors could present an additional possibility for treating resistant proneural tumors

UK multisite evaluation of the impact of clinical educators in EDs from a learner's perspective

BACKGROUND

In England, demand for emergency care is increasing while there is also a staffing shortage. The Royal College of Emergency Medicine (RCEM) suggested that appointment of senior doctors as clinical educators (CEs) would enable support and development of learners in EDs and improve retention and well-being. This study aimed to evaluate the impact of CEs in ED on learners.

METHODS

CEs were placed in 54 NHS Acute Trust EDs for a pilot beginning July 2018 and ending October 2020. Learners from multiple disciplines working at 54 NHS Acute Trust EDs where CEs were deployed were invited to complete an online survey designed to identify the impact of CEs in July of 2019, as part of an interim service evaluation.

RESULTS

Respondents numbered 493 from 49 of 54 study sites, including 286 (58%) medical (non-consultant) and 72 (14.6%) all other nursing, allied health professionals. 9 out of 10 learners reported having experienced a change to their learning as a result of the deployment of CEs in their department. 49.9% (246/493) reported that CEs had a positive impact on their well-being. 95% (340/358) reported an improved accessibility to undertaking clinical based assessments. 78% (281/358) perceived that access to CEs increased likelihood of passing assessments. Of those responding, 80.9% (399/493) reported they would remain/return to the same ED with a CE, and 92.5% (456/493) responded that they would prefer to go to a Trust with a CE.

CONCLUSIONS

According to survey respondents, deployment of CEs across NHS Trusts has resulted in improvement and increased accessibility of learning and assessment opportunities for learners within ED. The impact of CEs on well-being is uncertain with half reporting improvement and the remaining half unsure. Further evaluation within the project will continue to explore the service benefit and workforce impact of the CEED intervention.

129 Interim evaluation of a clinical educators pilot study via a multi-stakeholder online survey

Aims/Objectives/Background

In England, the demand for emergency care is increasing, confounded by challenges with recruitment and retention of multi-professional teams in Emergency Departments (ED). The intense working environment that clinical ED staff face is recognised as a cause of staff dissatisfaction, attrition and premature career ‘burnout.’ A new ‘shop floor’ Clinical Educator (CE) role may improve the retention and wellbeing of multi-professional ED teams. A Health Education England pilot developed and recruited CEs across 54 acute trust EDs in England, from 2017. Aston University and the Royal College of Emergency Medicine were jointly commissioned to undertake a service benefit evaluation.

Methods/Design

An online survey was circulated to CEs, learners and managers across the 54 study sites. Each group answered questions relating to experiences, opinions and reflections. Topics included impact of a CE on patient flow, confidence and competence of staff, as well as sustainability and any impact on staff wellbeing.

Results/Conclusions

Results

314 individuals accessed the survey and 291 eligible respondents completed it, including: 187 learners, 65 CEs and 39 ED Clinical Directors/Managers.

Learners (169/187), CE (63/65) and managers (39/39) saw no change/an improvement in patient flow.

100% of CEs felt that a CE in the ED improved competence and confidence of staff (88.2% of learners, 89.7% of managers).

7% (61/65) of CEs and 87.2% (34/39) managers agree that CEs have improved wellbeing of staff.

8% of managers (26/39) were unsure whether the CE role would be funded beyond the pilot, but 66.7% (26/39) strongly supported continuation of the CE role.

Conclusion

Interim evidence suggests that CEs positively impact the multi-professional ED workforce.

D-2-hydroxyglutaric aciduria in a patient with speech delay due to a novel homozygous deletion in the D2HGDH gene

D-2-hydroxyglutaric aciduria is a rare neurometabolic condition with a variable clinical spectrum. Here we report on a patient with speech delay, ascertained for an elevated urine 2-hydroxyglutaric acid levels, and found to have a novel pathogenic homozygous deletion in D2HGDH (NG_012012.1(NM_152783.4):c.(292 + 1_293–1)_(*847_?)del). This case expands on the reported phenotype, with speech delay being the prominent clinical finding and despite identifying a large deletion in the D2HGDH gene, the patient presents with the mild phenotype.

Taking the challenge: A protocolized approach to optimize Pneumocystis pneumonia prophylaxis in renal transplant recipients

While trimethoprim-sulfamethoxazole is considered first-line therapy for Pneumocystis pneumonia prevention in renal transplant recipients, reported adverse drug reactions may limit use and increase reliance on costly and less effective alternatives, often aerosolized pentamidine. We report our experience implementing a protocolized approach to trimethoprim-sulfamethoxazole adverse drug reaction assessment and rechallenge to optimize prophylaxis in this patient cohort. We retrospectively reviewed 119 patients receiving Pneumocystis pneumonia prophylaxis prior to and after protocol implementation. Forty-two patients (35%) had 48 trimethoprim-sulfamethoxazole adverse drug reactions documented either at baseline or during the prophylaxis period, of which 83% were non-immune-mediated and 17% were immune-mediated. Significantly more patients underwent trimethoprim-sulfamethoxazole rechallenge after protocol implementation (4/22 vs 23/27; P = .0001), with no recurrence of adverse drug reactions in 74%. In those who experienced a new or recurrent reaction (26%), all were mild and self-limiting with only 1 recurrence of an immune-mediated reaction. After protocol implementation, aerosolized pentamidine-associated costs were reduced. The introduction of a standard approach to trimethoprim-sulfamethoxazole rechallenge in the context of both prior immune and non-immune-mediated reactions was safe and successful in improving the uptake of first-line Pneumocystis pneumonia prophylaxis in renal transplant recipients.

Return to sender: the need to re-address patient antibiotic allergy labels in Australia and New Zealand

BACKGROUND/AIM

Antibiotic allergies are frequently reported and have significant impacts upon appropriate prescribing and clinical outcomes. We surveyed infectious diseases physicians, allergists, clinical immunologists and hospital pharmacists to evaluate antibiotic allergy knowledge and service delivery in Australia and New Zealand.

METHODS

An online multi-choice questionnaire was developed and endorsed by representatives of the Australasian Society of Clinical Immunology and Allergy (ASCIA) and the Australasian Society of Infectious Diseases (ASID). The 37-item survey was distributed in April 2015 to members of ASCIA, ASID, the Society of Hospital Pharmacists of Australia and the Royal Australasian College of Physicians.

RESULTS

Of 277 respondents, 94% currently use or would utilise antibiotic allergy testing (AAT) and reported seeing up to 10 patients/week labelled as antibiotic-allergic. Forty-two per cent were not aware of or did not have AAT available. Most felt that AAT would aid antibiotic selection, antibiotic appropriateness and antimicrobial stewardship (79, 69 and 61% respectively). Patients with the histories of immediate hypersensitivity were more likely to be referred than those with delayed hypersensitivities (76 vs 41%, P = 0.0001). Lack of specialist physicians (20%) and personal experience (17%) were barriers to service delivery. A multidisciplinary approach was a preferred AAT model (53%). Knowledge gaps were identified, with the majority overestimating rates of penicillin/cephalosporin (78%), penicillin/carbapenem (57%) and penicillin/monobactam (39%) cross-reactivity.

CONCLUSIONS

A high burden of antibiotic allergy labelling and demand for AAT is complicated by a relative lack availability or awareness of AAT services in Australia and New Zealand. Antibiotic allergy education and deployment of AAT, accessible to community and hospital-based clinicians, may improve clinical decisions and reduce antibiotic allergy impacts. A collaborative approach involving infectious diseases physicians, pharmacists and allergists/immunologists is required.

Sequence conservation predicts T cell reactivity against ragweed allergens

BACKGROUND

Ragweed is a major cause of seasonal allergy, affecting millions of people worldwide. Several allergens have been defined based on IgE reactivity, but their relative immunogenicity in terms of T cell responses has not been studied.

OBJECTIVE

We comprehensively characterized T cell responses from atopic, ragweed-allergic subjects to Amb a 1, Amb a 3, Amb a 4, Amb a 5, Amb a 6, Amb a 8, Amb a 9, Amb a 10, Amb a 11, and Amb p 5 and examined their correlation with serological reactivity and sequence conservation in other allergens.

METHODS

Peripheral blood mononuclear cells (PBMCs) from donors positive for IgE towards ragweed extracts after in vitro expansion for secretion of IL-5 (a representative Th2 cytokine) and IFN-γ (Th1) in response to a panel of overlapping peptides spanning the above-listed allergens were assessed.

RESULTS

Three previously identified dominant T cell epitopes (Amb a 1 176-191, 200-215, and 344-359) were confirmed, and three novel dominant epitopes (Amb a 1 280-295, 304-319, and 320-335) were identified. Amb a 1, the dominant IgE allergen, was also the dominant T cell allergen, but dominance patterns for T cell and IgE responses for the other ragweed allergens did not correlate. Dominance for T cell responses correlated with conservation of ragweed epitopes with sequences of other well-known allergens.

CONCLUSIONS AND CLINICAL RELEVANCE

These results provide the first assessment of the hierarchy of T cell reactivity in ragweed allergens, which is distinct from that observed for IgE reactivity and influenced by T cell epitope sequence conservation. The results suggest that ragweed allergens associated with lesser IgE reactivity and significant T cell reactivity may be targeted for T cell immunotherapy, and further support the development of immunotherapies against epitopes conserved across species to generate broad reactivity against many common allergens.

The role of different strain backgrounds in bacterial endotoxin-mediated sensitization to neonatal hypoxic-ischemic brain damage

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Strain background plays a role in the response to hypoxia–ischemia.

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LPS sensitizes the immature brain to hypoxia–ischemia across several mouse strains.

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Vehicle injection may induce immune response and sensitization to hypoxia–ischemia.

Genetic background is known to influence the outcome in mouse models of human disease, and previous experimental studies have shown strain variability in the neonatal mouse model of hypoxia–ischemia. To further map out this variability, we compared five commonly used mouse strains: C57BL/6, 129SVJ, BALB/c, CD1 and FVB in a pure hypoxic–ischemic setup and following pre-sensitization with lipopolysaccharide (LPS).

Postnatal day 7 pups were subjected to unilateral carotid artery occlusion followed by continuous 30 min 8% oxygen exposure at 36 °C. Twelve hours prior, a third of the pups received a single intraperitoneal LPS (0.6 μg/g) or a saline (vehicle) administration, respectively; a further third underwent hypoxia–ischemia alone without preceding injection. Both C57BL/6 and 129SVJ strains showed minimal response to 30 min hypoxia–ischemia alone, BALB/c demonstrated a moderate response, and both CD1 and FVB revealed the highest brain damage. LPS pre-sensitization led to substantial increase in overall brain infarction, microglial and astrocyte response and cell death in four of the five strains, with exception of BALB/c that only showed a significant effect with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Saline administration prior to hypoxia–ischemia resulted in an increase in inflammatory-associated markers, particularly in the astroglial activation of C57BL/6 mice, and in combined microglial activation and neuronal cell loss in FVB mice. Finally, two of the four strongly affected strains – C57BL/6 and CD1 – revealed pronounced contralateral astrogliosis with a neuroanatomical localization similar to that observed on the occluded hemisphere.

Overall, the current findings demonstrate strain differences in response to hypoxia–ischemia alone, to stress associated with vehicle injection, and to LPS-mediated pre-sensitization, which partially explains the high variability seen in the neonatal mouse models of hypoxia–ischemia. These results can be useful in future studies of fetal/neonatal response to inflammation and reduced oxygen–blood supply.

The Role of Choledochoscopy

Background. Identifying and surgically removing bile duct calculi is challenging and critical in order to provide good patient outcomes. The history of this surgical pursuit since the introduction of anesthesia is both enlightening and fascinating. Methods. A systematic review of the literature was conducted to identify the techniques and technology used to remove bile duct calculi. Results. All bile duct surgical exploration advances have involved creation of tools to look within the bile duct and extract stones. The Hopkin’s rod lens system was a major breakthrough in light and image transmission. However, flexible endoscope technology added the ability to maneuver better within the bile duct as well as apply the technology via laparoscopy enabling laparoscopic bile duct exploration. Conclusion. Digital, image enhanced, distal tipped chip flexible endoscopes have significantly improved the surgeons’ ability to see within the bile duct, improving the efficiency and ease of stone visualization and removal from both the most proximal and distal ends of the bile duct.

"I'm 100% for it! I'm a convert!": women's experiences of a yoga programme during treatment for gynaecological cancer; an interpretative phenomenological analysis

OBJECTIVES

To explore patients' experiences of taking part in a yoga intervention while undergoing treatment for gynaecological cancer.

DESIGN

Sixteen women (age range 31-79 years; mean age 60) participated in focus groups based on a semi-structured question schedule. Resulting discussions were audio-recorded, transcribed verbatim and analysed using interpretative phenomenological analysis (IPA).

SETTING

Royal Derby Hospital, UK.

INTERVENTIONS

Patients took part in a 10-week course of Hatha yoga, where they participated in a one hour long class per week.

RESULTS

Three themes emerged from the data: applying breathing techniques, engaging in the physicality of yoga and finding a community. The first theme was particularly important to the patients as they noted the breadth and applicability of the techniques in their day-to-day lives. The latter two themes reflect physical and social perspectives, which are established topics in the cancer and yoga literature and are contextualised here within the women's experiences of cancer treatment.

CONCLUSIONS

The women's perceptions of the programme were generally positive, providing a previously unseen view of the patient experience of participating in a yoga intervention. The difference between the women's prior expectations and lived experiences is discussed.

Dental Therapists

Dental therapists are members of the dental team in many countries, where they perform a limited number of irreversible restorative procedures. In the United States, they practice only in Alaska and Minnesota, though other states are considering adding them in an effort to improve access to care. While critics of this workforce model cite concern for patient safety, proponents argue that dental therapists provide treatment that is as technically competent as that provided by dentists. Though nearly 2 dozen studies from industrialized countries address this subject, this article systematically reviews all 23 of them. Of these reports, all but 2 conclude that dental therapists perform at an acceptable level. Every study that directly compared the work of dental therapists with that of dentists found that they performed at least as well. Regardless of whether dental therapists would be the most effective intervention for improving access to oral health care in the United States, the evidence clearly suggests dental therapists are clinically competent to safely perform the limited set of procedures that falls within their scope of practice.

Association between 25-OH vitamin D and insulin is independent of lipoatrophy in HIV

OBJECTIVE

Vitamin D deficiency (VDD) is prevalent in HIV, and following antiretroviral therapy (ART), increased rates of lipoatrophy and metabolic abnormalities are described. We investigated the relationships between 25-hydroxyvitamin D [25(OH)D] and other metabolic parameters in a group of HIV patients with and without lipoatrophy to examine whether lipoatrophy could explain the high prevalence of VDD and metabolic abnormalities.

BACKGROUND

Vitamin D receptors are expressed in adipose tissue implicating vitamin D, through paracrine/autocrine mechanism, in exerting effects on fat metabolism. HIV patients frequently suffer from VDD, and those treated with thymidine analogues frequently suffer from lipoatrophy so we investigated whether lipoatrophy could explain these associations.

DESIGN AND PATIENTS

Cross-sectional study of HIV-infected male patients (n = 107; 39 with lipoatrophy) from the West Australian cohort with measurements of 25(OH)D, adiponectin, insulin, lipids and leg fat as a percentage of mass.

RESULTS

Reduced 25(OH)D levels were common and significantly associated with higher serum insulin in the entire cohort (P = 0·006), but there was no difference in 25(OH)D between untreated and antiretroviral-treated patients with or without lipoatrophy. Treated patients with lipoatrophy were more likely to take thymidine analogue therapy, were older and on therapy longer than treated patients without lipoatrophy. Adiponectin levels did not correlate with 25(OH)D, but lipoatrophic-treated patients had lower levels of adiponectin compared with nonlipoatrophic-treated patients.

CONCLUSIONS

Lower 25(OH)D is associated with higher serum insulin but not lipoatrophy or hypoadiponectinemia in HIV-infected patients. The association between VDD and insulin resistance is likely to be mediated by independent mechanisms.

Growth of Strain SES-3 with Arsenate and Other Diverse Electron Acceptors

The selenate-respiring bacterial strain SES-3 was able to use a variety of inorganic electron acceptors to sustain growth. SES-3 grew with the reduction of arsenate to arsenite, Fe(III) to Fe(II), or thiosulfate to sulfide. It also grew in medium in which elemental sulfur, Mn(IV), nitrite, trimethylamine N-oxide, or fumarate was provided as an electron acceptor. Growth on oxygen was microaerophilic. There was no growth with arsenite or chromate. Washed suspensions of cells grown on selenate or nitrate had a constitutive ability to reduce arsenate but were unable to reduce arsenite. These results suggest that strain SES-3 may occupy a niche as an environmental opportunist by being able to take advantage of a diversity of electron acceptors.