Examining the utility of extended laboratory panel testing in the emergency department for risk stratification of patients with COVID-19: a single-centre retrospective service evaluation

BACKGROUND

The role of specific blood tests to predict poor prognosis in patients admitted with infection from SARS-CoV-2 remains uncertain. During the first wave of the global pandemic, an extended laboratory testing panel was integrated into the local pathway to guide triage and healthcare resource utilisation for emergency admissions. We conducted a retrospective service evaluation to determine the utility of extended tests (D-dimer, ferritin, high-sensitivity troponin I, lactate dehydrogenase and procalcitonin) compared with the core panel (full blood count, urea and electrolytes, liver function tests and C reactive protein).

METHODS

Clinical outcomes for adult patients with laboratory-confirmed COVID-19 admitted between 17 March and 30 June 2020 were extracted, alongside costs estimates for individual tests. Prognostic performance was assessed using multivariable logistic regression analysis with 28-day mortality used as the primary endpoint and a composite of 28-day intensive care escalation or mortality for secondary analysis.

RESULTS

From 13 500 emergency attendances, we identified 391 unique adults admitted with COVID-19. Of these, 113 died (29%) and 151 (39%) reached the composite endpoint. 'Core' test variables adjusted for age, gender and index of deprivation had a prognostic area under the curve of 0.79 (95% CI 0.67 to 0.91) for mortality and 0.70 (95% CI 0.56 to 0.84) for the composite endpoint. Addition of 'extended' test components did not improve on this.

CONCLUSION

Our findings suggest use of the extended laboratory testing panel to risk stratify community-acquired COVID-19 positive patients on admission adds limited prognostic value. We suggest laboratory requesting should be targeted to patients with specific clinical indications.

Diagnosis of colorectal and emergency surgical site infections in the era of enhanced recovery: an all-Wales prospective study

AIM

Surgical site infections (SSIs) are associated with increased morbidity, hospital stay and cost. The literature reports that 25% of patients who undergo colorectal surgical procedures develop a SSI. Due to the enhanced recovery programme, patients are being discharged earlier with some SSIs presenting in primary care, making accurate recording of SSIs difficult. The aim of this study was to accurately record the 30-day SSI rate after surgery performed by colorectal surgeons nationally within Wales.

METHOD

During March 2019, a national prospective snapshot study of all patients undergoing elective or emergency colorectal and general surgical procedures under the care of a colorectal consultant at 12 Welsh hospitals was completed. There was a multimodal 30-day follow-up using electronic records, clinic visits and/or telephone calls. Diagnosis of SSI was based on Centers for Disease Control and Prevention diagnostic criteria.

RESULTS

Within Wales, of the 545 patients included, 13% developed a SSI within 30 days, with SSI rates of 14.3% for elective surgery and 11.7% for emergency surgery. Of these SSIs, 49.3% were diagnosed in primary care, with 28.2% of patients being managed exclusively in the community. There were two peaks of diagnosis at days 5-7 and days 22-28. SSI rates between laparoscopic (8.6%) and open (16.2%) surgeries were significantly different (p = 0.028), and there was also a significantly different rate of SSI between procedure groups (p = 0.001), with high SSI rates for colon (22%) and rectal (18.9%) surgery compared with general surgical procedures.

CONCLUSION

This first all-Wales prospective study demonstrated an overall SSI rate of 13%. By incorporating accurate primary care follow-up it was found that 49.3% of these SSIs were diagnosed in primary care.

Identification of clinical and urine biomarkers for uncomplicated urinary tract infection using machine learning algorithms

Women with uncomplicated urinary tract infection (UTI) symptoms are commonly treated with empirical antibiotics, resulting in overuse of antibiotics, which promotes antimicrobial resistance. Available diagnostic tools are either not cost-effective or diagnostically sub-optimal. Here, we identified clinical and urinary immunological predictors for UTI diagnosis. We explored 17 clinical and 42 immunological potential predictors for bacterial culture among women with uncomplicated UTI symptoms using random forest or support vector machine coupled with recursive feature elimination. Urine cloudiness was the best performing clinical predictor to rule out (negative likelihood ratio [LR−] = 0.4) and rule in (LR+ = 2.6) UTI. Using a more discriminatory scale to assess cloudiness (turbidity) increased the accuracy of UTI prediction further (LR+ = 4.4). Urinary levels of MMP9, NGAL, CXCL8 and IL-1β together had a higher LR+ (6.1) and similar LR− (0.4), compared to cloudiness. Varying the bacterial count thresholds for urine culture positivity did not alter best clinical predictor selection, but did affect the number of immunological predictors required for reaching an optimal prediction. We conclude that urine cloudiness is particularly helpful in ruling out negative UTI cases. The identified urinary biomarkers could be used to develop a point of care test for UTI but require further validation.

Altered Gut Microbiota Activate and Expand Insulin B15-23-Reactive CD8+ T Cells

Insulin is a major autoantigen in type 1 diabetes, targeted by both CD8 and CD4 T cells. We studied an insulin-reactive T-cell receptor (TCR) α-chain transgenic NOD mouse on a TCRCα and proinsulin 2 (PI2)-deficient background, designated as A22Cα^-/-PI2^-/- NOD mice. These mice develop a low incidence of autoimmune diabetes. To test the role of gut microbiota on diabetes development in this model system, we treated the A22Cα^-/-PI2^-/- NOD mice with enrofloxacin, a broad-spectrum antibiotic. The treatment led to male mice developing accelerated diabetes. We found that enrofloxacin increased the frequency of the insulin-reactive CD8+ T cells and activated the cells in the Peyer's patches and pancreatic lymph nodes, together with induction of immunological effects on the antigen-presenting cell populations. The composition of gut microbiota differed between the enrofloxacin-treated and untreated mice and also between the enrofloxacin-treated mice that developed diabetes compared with those that remained normoglycemic. Our results provide evidence that the composition of the gut microbiota is important for determining the expansion and activation of insulin-reactive CD8+ T cells.

An improved cell-permeable fluorogenic substrate as the basis for a highly sensitive test for NAD(P)H quinone oxidoreductase 1 (NQO1) in living cells

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a flavoenzyme upregulated in response to oxidative stress and in some cancers. Its upregulation by compounds has been used as an indicator of their potential anti-cancer properties. In this study we have designed, produced and tested a fluorogenic coumarin conjugate which selectively releases highly fluorescent 4-methylumbelliferone (4-MU) in the presence of NQO1. It was found that measuring 4-MU release rapidly and specifically quantitated NQO1 levels in vitro and in live cells. Both the substrate and its products freely perfused through cell membranes and were non-toxic. The substrate was very specific with low background, and the assay itself could be done in less than 10minutes. This is the first assay to allow the quantitation of NQO1 in live cells which can then be retained for further experiments.

Abstract 550: Evaluation of NQO1 as a potential diagnostic marker for bladder cancer

The present method for detection of bladder cancer involves ultrasonography followed by cystoscopy. This process is time intensive, requires skilled personnel and is unpleasant for the patient as a result of its invasive nature. This results in patient drop-out and patients that have recovered from bladder cancer are lost to follow-up due to the necessity for hospital visits for monitoring. We have used a novel test in order to monitor NAD(P)H quinone oxidoreductase 1 (NQO1) activity in cells recovered from routine urine samples since expression of NQO1 has previously been reported to be increased in several tumour types including transitional cell carcinoma of the bladder.

Informed consent and urine samples were obtained from 73 bladder cancer patients and 42 age-matched bladder cancer-negative outpatients at the University Hospital of Wales, Cardiff. Live exfoliated cells were collected from the urine and assessed for their ability to metabolise an NQO1-specific substrate into a highly fluorescent product. Fluorescence intensity was then measured in a simple, inexpensive instrument. Results were checked against clinical correlates, bladder cancer stage, age, medication, and smoking status. Initial tests in cell lines showed excellent correlation with NQO1 levels detected by other methods. We found that in patient samples, while cell numbers in urine and expression of NQO1 per cell were not in themselves significant, NQO1 per ml of urine was highly significantly increased in bladder cancer patients (p = 0.009). Further, NQO1 was higher in patients that had high grade tumours as described in the WHO 2004 guidelines (p = 0.003).

The sensitive fluorescence-based method to detect NQO1 activity in exfoliated urothelial cells shows exceptional promise in the development of rapid, non-invasive bladder cancer diagnostics. The method will be used on larger numbers of samples in order to be able to verify these initial findings.

Note: This abstract was not presented at the meeting.

Citation Format: Simone Cuff, Ruth Lewis, Mohammed Jaffar, Richard Knox, Ian Weeks. Evaluation of NQO1 as a potential diagnostic marker for bladder cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 550. doi:10.1158/1538-7445.AM2015-550

Oncogenic properties of apoptotic tumor cells in aggressive B cell lymphoma

Background

Cells undergoing apoptosis are known to modulate their tissue microenvironments. By acting on phagocytes, notably macrophages, apoptotic cells inhibit immunological and inflammatory responses and promote trophic signaling pathways. Paradoxically, because of their potential to cause death of tumor cells and thereby militate against malignant disease progression, both apoptosis and tumor-associated macrophages (TAMs) are often associated with poor prognosis in cancer. We hypothesized that, in progression of malignant disease, constitutive loss of a fraction of the tumor cell population through apoptosis could yield tumor-promoting effects.

Results

Here, we demonstrate that apoptotic tumor cells promote coordinated tumor growth, angiogenesis, and accumulation of TAMs in aggressive B cell lymphomas. Through unbiased “in situ transcriptomics” analysis—gene expression profiling of laser-captured TAMs to establish their activation signature in situ—we show that these cells are activated to signal via multiple tumor-promoting reparatory, trophic, angiogenic, tissue remodeling, and anti-inflammatory pathways. Our results also suggest that apoptotic lymphoma cells help drive this signature. Furthermore, we demonstrate that, upon induction of apoptosis, lymphoma cells not only activate expression of the tumor-promoting matrix metalloproteinases MMP2 and MMP12 in macrophages but also express and process these MMPs directly. Finally, using a model of malignant melanoma, we show that the oncogenic potential of apoptotic tumor cells extends beyond lymphoma.

Conclusions

In addition to its profound tumor-suppressive role, apoptosis can potentiate cancer progression. These results have important implications for understanding the fundamental biology of cell death, its roles in malignant disease, and the broader consequences of apoptosis-inducing anti-cancer therapy.

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Apoptotic lymphoma cells promote tumor growth, angiogenesis, and TAM accumulation

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Unbiased “in situ transcriptomics” analysis shows TAMs promote pro-tumor pathways

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Apoptotic tumor cells express and process matrix remodeling proteins

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The oncogenic potential of apoptotic tumor cells extends beyond lymphoma

Two novel human cytomegalovirus NK cell evasion functions target MICA for lysosomal degradation

NKG2D plays a major role in controlling immune responses through the regulation of natural killer (NK) cells, αβ and γδ T-cell function. This activating receptor recognizes eight distinct ligands (the MHC Class I polypeptide-related sequences (MIC) A andB, and UL16-binding proteins (ULBP)1-6) induced by cellular stress to promote recognition cells perturbed by malignant transformation or microbial infection. Studies into human cytomegalovirus (HCMV) have aided both the identification and characterization of NKG2D ligands (NKG2DLs). HCMV immediate early (IE) gene up regulates NKGDLs, and we now describe the differential activation of ULBP2 and MICA/B by IE1 and IE2 respectively. Despite activation by IE functions, HCMV effectively suppressed cell surface expression of NKGDLs through both the early and late phases of infection. The immune evasion functions UL16, UL142, and microRNA(miR)-UL112 are known to target NKG2DLs. While infection with a UL16 deletion mutant caused the expected increase in MICB and ULBP2 cell surface expression, deletion of UL142 did not have a similar impact on its target, MICA. We therefore performed a systematic screen of the viral genome to search of addition functions that targeted MICA. US18 and US20 were identified as novel NK cell evasion functions capable of acting independently to promote MICA degradation by lysosomal degradation. The most dramatic effect on MICA expression was achieved when US18 and US20 acted in concert. US18 and US20 are the first members of the US12 gene family to have been assigned a function. The US12 family has 10 members encoded sequentially through US12-US21; a genetic arrangement, which is suggestive of an 'accordion' expansion of an ancestral gene in response to a selective pressure. This expansion must have be an ancient event as the whole family is conserved across simian cytomegaloviruses from old world monkeys. The evolutionary benefit bestowed by the combinatorial effect of US18 and US20 on MICA may have contributed to sustaining the US12 gene family.

Human cytomegalovirus UL40 signal peptide regulates cell surface expression of the NK cell ligands HLA-E and gpUL18

Human CMV (HCMV)-encoded NK cell-evasion functions include an MHC class I homolog (UL18) with high affinity for the leukocyte inhibitory receptor-1 (CD85j, ILT2, or LILRB1) and a signal peptide (SP(UL40)) that acts by upregulating cell surface expression of HLA-E. Detailed characterization of SP(UL40) revealed that the N-terminal 14 aa residues bestowed TAP-independent upregulation of HLA-E, whereas C region sequences delayed processing of SP(UL40) by a signal peptide peptidase-type intramembrane protease. Most significantly, the consensus HLA-E-binding epitope within SP(UL40) was shown to promote cell surface expression of both HLA-E and gpUL18. UL40 was found to possess two transcription start sites, with utilization of the downstream site resulting in translation being initiated within the HLA-E-binding epitope (P2). Remarkably, this truncated SP(UL40) was functional and retained the capacity to upregulate gpUL18 but not HLA-E. Thus, our findings identify an elegant mechanism by which an HCMV signal peptide differentially regulates two distinct NK cell-evasion pathways. Moreover, we describe a natural SP(UL40) mutant that provides a clear example of an HCMV clinical virus with a defect in an NK cell-evasion function and exemplifies issues that confront the virus when adapting to immunogenetic diversity in the host.

Antigen specificity determines the pro- or antitumoral nature of CD8+ T cells

Although CD8+ T cells are usually considered antitumoral, several recent studies report that the cells can also promote tumor progression. Using the melanoma cell line B16 as a murine model of pulmonary metastasis, we examined whether the pro- versus antitumoral effects of CD8+ T cells relate to their Ag specificity. Results of the study indicate that although CD8+ T cells specific for tumor Ags promote tumor rejection, CD8+ T cells specific for unrelated Ags promote tumor progression. We found the effect to be partly attributable to CD8+ T cells dampening effective antitumor NK cell responses. Notably, activation of CD8+ T cell responses by an unrelated stimulus, in this case infection with influenza virus, increased the number of pulmonary tumor nodules. These data provide a rationale for previously unexplained data identifying contrasting roles for CD8+ T cells in tumor progression.

Antigen-independent accumulation of activated effector/memory T lymphocytes into human and murine tumors

Tumor infiltrating lymphocytes (TIL) display activation markers and their presence is often associated with a favorable outcome. The role of tumor antigens in T cell recruitment into tumors is unclear. In an attempt to address this issue, we purified lymphocytes from breast tumor or nontumor, mammary tissue from patients, and normal mammary tissue from healthy individuals. In all groups, including healthy individuals, the majority of cells displayed an effector/memory (CD45RA(lo)/CD27(+/-)) phenotype and quite surprisingly the early and transient activation marker CD69, thus, questioning the tumor antigen specificity of TIL. Because the human repertoire is diverse, the T cells found in the tumors could recognize both self/tumor and environmental antigens through cross-reactivity. To test this hypothesis, we used two anti-male HY monospecific TCR transgenic mouse models. We found an infiltration of HY negative tumors by the CD4(+) and CD8(+) monoclonal T cells after priming with HY positive cells in the periphery. Thus, the presence of activated effector/memory T lymphocytes in tumors can be independent of reactivity against tumor antigens. These results suggest that to find activated effector T cells in a tissue does not always mean that a specific immune response is taking place.

Preparation and achievement of American College of Surgeons level I trauma verification raises hospital performance and improves patient outcome

OBJECTIVE

The purpose of this study was to assess the impact on patient outcome and hospital performance of preparing for and achieving American College of Surgeons (ACS) Level I trauma verification.

METHODS

The center was a previously designated state regional trauma center located adjacent to a major metropolitan area. Preparation for ACS verification began in early 1996 and was completed in early 1998. Final verification took place in April 1999. Data were analyzed before (1994) and after (1998) the process. There was a marked increase in administrative support with trauma named one of the hospital's six centers of excellence. Two full-time board-certified trauma/critical care surgeons were added to the current six trauma surgeons. Their major focus was trauma care. Trauma support staff was also increased with case managers, a trauma nurse practitioner, additional trauma registrars, and administrative support staff. Education and continuous quality improvement were markedly expanded starting in 1996.

RESULTS

There were 1,098 trauma patients admitted in 1994, and 1,658 in 1998. Overall mortality decreased (1994, 7.38%; 1998, 5.37%; p < 0.05). There was a marked decrease in mortality for severely injured (Injury Severity Score > 30) patients (1994, 44% mortality [38 of 86]; 1998, 27% [22 of 80]; p < 0.04). Average length of stay also decreased (1994, 12.22 days; 1998, 9.87 days; p < 0.02). This yielded an estimated cost savings for 1998 of greater than $4,000 per patient (total saving estimate of $7.4 million).

CONCLUSION

Trauma system improvement as related to achieving ACS Level I verification appeared to have a positive impact on survival and patient care. There were cost savings realized that helped alleviate the added expense of this system improvement. The process of achieving ACS Level I verification is worthwhile and can be cost effective.

Evasion of apoptosis by DNA viruses

Apoptosis is a form of cell death distinct from necrosis which plays an important role in processes such as homoeostasis and the elimination of damaged cells. It can be triggered by a variety of stimuli including DNA damage and cytotoxic T lymphocyte activity, both of which may be induced in the course of a viral infection. Initially, induction of apoptosis may occur through pathways which have also been shown to be activated on disturbance of the cell cycle or damage to cellular DNA. At later time points during the course of infection, apoptosis can also be triggered by cytokines and immune effector cells. Apoptosis of the host cell before the completion of the viral replication cycle may limit the number of progeny and the spread of infection. The importance of apoptosis as an antiviral defence is illustrated by the presence of multiple pathways for apoptosis induction and inhibition in both the host and virus. In this review, the inhibition of apoptosis is described in adenovirus and poxvirus infection. These examples illustrate two of the divergent paths by which viruses may avoid the apoptotic response.