Banff 2022 Vascularized Composite Allotransplantation Meeting Report: Diagnostic criteria for vascular changes

As more data become available, the Banff 2007 working classification of skin-containing vascularized composite allograft (VCA) pathology is expected to evolve and develop. This report represents the Banff VCA Working Group's consensus on the first revision of the 2007 scoring system. Prior to the 2022 Banff-CanXadian Society of Transplantation Joint Meeting, 83 clinicians and/or researchers were invited to a virtual meeting to discuss whether the 2007 Banff VCA system called for a revision. Unanimously, it was determined that the vascular changes were to be included in the first revision. Subsequently, 2 international online surveys, each followed by virtual discussions, were launched. The goals were (1) to identify which changes define severe rejection, (2) to grade their importance in the evaluation of severe rejection, and (3) to identify emerging criteria to diagnose rejection. A final hybrid (in-person and virtual) discussion at the Banff/Canadian Society of Transplantation Joint Meeting finalized the terminology, the definition, a scoring system, and a reporting system of the vascular changes. This proposal represents an international consensus on this topic and establishes the first revision of the Banff 2007 working classification of skin-containing vascularized composite allograft pathology.

Determining the Impact of Hurricane Dorian and the Covid-19 Pandemic on Moral Distress in Emergency Medical Providers at the Rand Memorial Hospital: Moral distress in emergency medical personnel

OBJECTIVES

The aim of this work was to determine the impact of Moral Distress (MD) in emergency physicians, nurses, and emergency medical service staff at the Rand Memorial Hospital (RMH) in the Bahamas, and the impact of Hurricane Dorian and the COVID-19 pandemic on Moral Distress.

METHOD

A cross-sectional study utilizing a 3-part survey, which collected sociodemographic information, Hurricane Dorian and COVID-19 experiences, as well as responses to a validated modified Moral Distress Scale (MDS).

RESULTS

Participants with 2 negatively impactful experiences from COVID-19 had statistically significantly increased MD compared to participants with only 1 negatively impactful experience (40.4 vs. 23.6, P = 0.014). Losing a loved one due to COVID-19 was associated with significantly decreased MD (B = - 0.42, 95% CI -19.70 to -0.88, P = 0.03). Losing a loved one due to Hurricane Dorian had a non-statistically significant trend towards higher MD scores (B = 0.34, 95% CI -1.23 to 28.75, P = 0.07).

CONCLUSION

The emergency medical staff at the RMH reported having mild - moderate MD. This is one of the first studies to look at the impact of concurrent disasters on MD in emergency medical providers in the Bahamas.

Decoding mTOR signalling heterogeneity in the tumour microenvironment using multiplexed imaging and graph convolutional networks

Evaluating the contribution of the tumour microenvironment (TME) in tumour progression has proven a complex challenge due to the intricate interactions within the TME. Multiplexed imaging is an emerging technology that allows concurrent assessment of multiple of these components simultaneously. Here we utilise a highly multiplexed dataset of 61 markers across 746 colorectal tumours to investigate how complex mTOR signalling in different tissue compartments influences patient prognosis. We found that the signalling of mTOR pathway can have heterogeneous activation patterns in tumour and immune compartments which correlate with patient prognosis. Using graph neural networks, we determined the most predictive features of mTOR activity in immune cells and identified relevant cellular subpopulations. We validated our observations using spatial transcriptomics data analysis in an independent patient cohort. Our work provides a framework for studying complex cell signalling and reveals important insights for developing mTOR-based therapies.

Opportunities for High-plex Spatial Transcriptomics in Solid Organ Transplantation

The last 5 y have seen the development and widespread adoption of high-plex spatial transcriptomic technology. This technique detects and quantifies mRNA transcripts in situ, meaning that transcriptomic signatures can be sampled from specific cells, structures, lesions, or anatomical regions while conserving the physical relationships that exist within complex tissues. These methods now frequently implement next-generation sequencing, enabling the simultaneous measurement of many targets, up to and including the whole mRNA transcriptome. To date, spatial transcriptomics has been foremost used in the fields of neuroscience and oncology, but there is potential for its use in transplantation sciences. Transplantation has a clear dependence on biopsies for diagnosis, monitoring, and research. Transplant patients represent a unique cohort with multiple organs of interest, clinical courses, demographics, and immunosuppressive regimens. Obtaining high complexity data on the disease processes underlying rejection, tolerance, infection, malignancy, and injury could identify new opportunities for therapeutic intervention and biomarker identification. In this review, we discuss currently available spatial transcriptomic technologies and how they can be applied to transplantation.

Syndromic Surveillance Implementation During Disaster Events

INTRODUCTION

Disease surveillance is an integral part of public health. These systems monitor disease trends and detect outbreaks, whereas they should be evaluated for efficacy. The United States Centres for Disease Control and Prevention publish Guidelines for Evaluating Surveillance Systems to encourage efficient and effective use of public health surveillance that are accepted worldwide.

OBJECTIVE

This study reviews syndromic surveillance during natural and man-made disasters internationally. It aims to (1) review the performance of syndromic surveillance via pre-specified attributes during disaster and to (2) understand its strengths and limitations.

METHODS

PubMed was systematically searched for the articles assessing syndromic surveillance during a disaster. A narrative review was carried out based on those articles. Updated Guidelines for Evaluating Public Health Surveillance Systems were used to review performance of systems.

RESULTS

5,059 studies from PubMed were evaluated, and 16 met inclusion criteria. The majority of these studies considered the implementation of syndromic surveillance useable during disaster events. Studies described systems giving relevant and timely information. Simplicity and timeliness were the most highlighted attributes.

CONCLUSION

Syndromic surveillance is simple, flexible, useful and usable during a disaster. Timely data can be obtained, but the quality of this type of data is sensitive to incomplete and erroneous reporting; because of this, a standardized approach is necessary to optimize these systems.

Single cell spatial analysis reveals inflammatory foci of immature neutrophil and CD8 T cells in COVID-19 lungs

Single cell spatial interrogation of the immune-structural interactions in COVID -19 lungs is challenging, mainly because of the marked cellular infiltrate and architecturally distorted microstructure. To address this, we develop a suite of mathematical tools to search for statistically significant co-locations amongst immune and structural cells identified using 37-plex imaging mass cytometry. This unbiased method reveals a cellular map interleaved with an inflammatory network of immature neutrophils, cytotoxic CD8 T cells, megakaryocytes and monocytes co-located with regenerating alveolar progenitors and endothelium. Of note, a highly active cluster of immature neutrophils and CD8 T cells, is found spatially linked with alveolar progenitor cells, and temporally with the diffuse alveolar damage stage. These findings offer further insights into how immune cells interact in the lungs of severe COVID-19 disease. We provide our pipeline [Spatial Omics Oxford Pipeline (SpOOx)] and visual-analytical tool, Multi-Dimensional Viewer (MDV) software, as a resource for spatial analysis.

An Immune Atlas of T Cells in Transplant Rejection: Pathways and Therapeutic Opportunities

Short-term outcomes in allotransplantation are excellent due to technical and pharmacological advances; however, improvement in long-term outcomes has been limited. Recurrent episodes of acute cellular rejection, a primarily T cell-mediated response to transplanted tissue, have been implicated in the development of chronic allograft dysfunction and loss. Although it is well established that acute cellular rejection is primarily a CD4 + and CD8 + T cell mediated response, significant heterogeneity exists within these cell compartments. During immune responses, naïve CD4 + T cells are activated and subsequently differentiate into specific T helper subsets under the influence of the local cytokine milieu. These subsets have distinct phenotypic and functional characteristics, with reported differences in their contribution to rejection responses specifically. Of particular relevance are the regulatory subsets and their potential to promote tolerance of allografts. Unraveling the specific contributions of these cell subsets in the context of transplantation is complex, but may reveal new avenues of therapeutic intervention for the prevention of rejection.

Computerized adaptive testing for the patient evaluation measure (PEM) in patients undergoing cubital tunnel syndrome surgery

In outcome measures, item response theory (IRT) validation can deliver interval-scaled high-quality measurement that can be harnessed using computerized adaptive tests (CATs) to pose fewer questions to patients. We aimed to develop a CAT by developing an IRT model for the Patient Evaluation Measure (PEM) for patients undergoing cubital tunnel syndrome (CuTS) surgery. Nine hundred and seventy-nine completed PEM responses of patients with CuTS in the United Kingdom Hand Registry were used to develop and calibrate the CAT. Its performance was then evaluated in a simulated cohort of 1000 patients. The CAT reduced the original PEM length from ten to a median of two questions (range two to four), while preserving a high level of precision (median standard error of measurement of 0.27). The mean error between the CAT score and full-length score was 0.08%. A Bland-Altman analysis showed good agreement with no signs of bias. The CAT version of the PEM can substantially reduce patient burden while enhancing construct validity by harnessing IRT for patients undergoing CuTS surgery.

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

BACKGROUND

Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.

METHODS

This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low-middle-income countries.

RESULTS

In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of 'single-use' consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low-middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.

CONCLUSION

This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high- and low-middle-income countries.

Factors associated with international humanitarian aid appeal for disasters from 1995 to 2015: A retrospective database study

INTRODUCTION

International humanitarian aid during disasters should be needs-based and coordinated in response to appeals from affected governments. We identify disaster and population factors associated with international aid appeal during disasters and hence guide preparation by international humanitarian aid providers.

METHODS

In this retrospective database analysis, we searched the Emergency Events Database for all disasters from 1995 to 2015. Disasters with and without international aid appeals were compared by location, duration, type of disaster, deaths, number of people affected, and total estimated damage. Logistic regression was used to examine the association of each factor with international aid appeal.

RESULTS

Of 13,961 disasters recorded from 1995 to 2015, 168 (1.2%) involved international aid appeals. Aid appeals were more likely to be triggered by disasters which killed more people (OR 1.29 [95% confidence interval (CI) 1.02-1.64] log10 persons), affected more people (OR 1.85 [95%CI 1.57-2.18] / log10 persons), and occurred in Africa (OR 1.67 [95%CI 1.06-2.62). Earthquakes (OR 4.07 [95%CI 2.16-7.67]), volcanic activity (OR 6.23 [95%CI 2.50-15.53]), and insect infestations (OR 12.14 [95%CI 3.05-48.35]) were more likely to trigger international aid appeals. International aid appeals were less likely to be triggered by disasters which occurred in Asia (OR 0.46 [95%CI 0.29-0.73]) and which were transport accidents (OR 0.12 [95%CI 0.02-0.89]).

CONCLUSION

International aid appeal during disasters was associated with greater magnitude of damage, disasters in Africa, and specific types of disasters such as earthquakes, volcanic activity, and insect infestations. Humanitarian aid providers can focus preparation on these identified factors.

Research and Innovation in Organ Donation: Recommendations From an International Consensus Forum

This report provides recommendations from the Research and Innovation domain as part of the International Donation and Transplantation Legislative and Policy Forum (hereafter the Forum) to provide expert guidance on the structure of an ideal organ and tissue donation and transplantation system. The recommendations focus on deceased donation research and are intended for clinicians, investigators, decision-makers, and patient, family, and donor (PFD) partners involved in the field.

Methods

We identified topics impacting donation research through consensus using nominal group technique. Members performed narrative reviews and synthesized current knowledge on each topic, which included academic articles, policy documents, and gray literature. Using the nominal group technique, committee members discussed significant findings, which provided evidence for our recommendations. The Forum's scientific committee then vetted recommendations.

Results

We developed 16 recommendations in 3 key areas to provide stakeholders guidance in developing a robust deceased donor research framework. These include PFD and public involvement in research; donor, surrogate, and recipient consent within a research ethics framework; and data management. We highlight the importance of PFD and public partner involvement in research, we define the minimum ethical requirements for the protection of donors and recipients of both target and nontarget organ recipients, and we recommend the creation of a centrally administered donor research oversight committee, a single specialist institutional review board, and a research oversight body to facilitate coordination and ethical oversight of organ donor intervention research.

Conclusions

Our recommendations provide a roadmap for developing and implementing an ethical deceased donation research framework that continually builds public trust. Although these recommendations can be applied to jurisdictions developing or reforming their organ and tissue donation and transplantation system, stakeholders are encouraged to collaborate and respond to their specific jurisdictional needs related to organ and tissue shortages.

Direct correction of haemoglobin E β-thalassaemia using base editors

Haemoglobin E (HbE) β-thalassaemia causes approximately 50% of all severe thalassaemia worldwide; equating to around 30,000 births per year. HbE β-thalassaemia is due to a point mutation in codon 26 of the human HBB gene on one allele (GAG; glutamatic acid → AAG; lysine, E26K), and any mutation causing severe β-thalassaemia on the other. When inherited together in compound heterozygosity these mutations can cause a severe thalassaemic phenotype. However, if only one allele is mutated individuals are carriers for the respective mutation and have an asymptomatic phenotype (β-thalassaemia trait). Here we describe a base editing strategy which corrects the HbE mutation either to wildtype (WT) or a normal variant haemoglobin (E26G) known as Hb Aubenas and thereby recreates the asymptomatic trait phenotype. We have achieved editing efficiencies in excess of 90% in primary human CD34 + cells. We demonstrate editing of long-term repopulating haematopoietic stem cells (LT-HSCs) using serial xenotransplantation in NSG mice. We have profiled the off-target effects using a combination of circularization for in vitro reporting of cleavage effects by sequencing (CIRCLE-seq) and deep targeted capture and have developed machine-learning based methods to predict functional effects of candidate off-target mutations.

Threat awareness training for non-governmental organizations deploying humanitarian aid workers into conflict environments

INTRODUCTION

The current war in Ukraine and the subsequent deployment of Non-Governmental Organizations (NGOs) from around the world has highlighted the many potential dangers faced by humanitarian aid workers operating in conflict zones. Humanitarian aid workers may face both direct and indirect threats and aggression while on deployment, and given the rising number of global conflicts, the authors postulate a need to incorporate threat awareness training as part of pre-deployment training.

METHODS

A list of the top 22 rated NGOs providing international aid was obtained from CharityWatch. All 22 were contacted via their public email addresses or website contact pages to find out if they provide any form of security, tactical or threat awareness training.

RESULTS

Of the 13 NGOs that responded, 7 did not deploy staff into recent conflict zones or surroundings. All 6 NGOs who deployed staff into Ukraine or surrounding border countries, provided either security, tactical or threat awareness training to their staff.

CONCLUSION

With the rising number of conflicts and disasters around the world, humanitarian aid workers are increasingly exposed to hostile environments and there is a compelling need for NGOs to ensure staff are adequately trained and prepared to handle any dangers and threats they may face. In this study, all 6 of the studied NGOs which deployed staff to the conflict zone confirmed some type of security or threat awareness training ranging from in-house security briefs to extensive, multi-day, commercially run courses such as Hostile Environment Awareness Training course.

Terrorism-Related Attacks in East Asia from 1970 through 2020

AIM

This study aims to analyze and describe terrorism-related attacks in East Asia from 1970 through 2020.

BACKGROUND

East Asia consists of South Korea, North Korea, Singapore, Hong Kong, China, Japan, Taiwan, and Macao. According to the Global Terrorism Index (GTI) 2022, the impact of terrorism in East Asia is very low. However, the assassination of former Japanese Prime Minister Shinzo Abe on July 8, 2022 demonstrates that East Asia is not safe from terrorist attacks. This descriptive analysis of terrorist attacks in East Asia will help first responders, Emergency Medical Services (EMS), hospital-based medical providers, and policymakers establish a more refined hazard vulnerability assessment (HVA) framework and develop a Counter-Terrorism Medicine (CTM) mitigation, preparedness, response, and recovery plan.

METHODS

This is a descriptive observational study drawing data from the Global Terrorism Database (GTD) from January 1, 1970 through December 31, 2020. Epidemiology outcomes included primary weapon type, primary target type, the country where the incident occurred, and the number of total deaths and injured collected. Data from 2021 were not yet available at the time of this study. Results were exported into an Excel spreadsheet (Microsoft Corp.; Redmond, Washington USA) for analysis.

RESULTS

There were 779 terrorism-related events in East Asia from 1970 through 2020. In total, the attacks resulted in 1,123 deaths and 9,061 persons injured. The greatest number of attacks (371; 47.63%) occurred in Japan and the second most occurred in China (268; 34.4%). Explosives were the most used primary weapon type (308; 39.54%) in the region, followed by incendiary devices (260; 33.38%). Terrorist attacks drastically diminished from their peak of 92 in 1990, but there were additional peaks of 88 in 1996, 18 in 2000, 20 in 2008, and 36 attacks in 2014.

CONCLUSIONS

A total of 779 terrorist attacks occurred from 1970 through 2020 in East Asia, resulting in 1,123 deaths and 9,061 injuries. Of those, 82.03% attacks occurred in Japan and China. Terrorist attacks drastically diminished since their peak in 1996, but there is an overall uptrend in attacks since 1999.

Regulatory T-cell therapy approaches

Regulatory T cells (Tregs) have enormous therapeutic potential to treat a variety of immunopathologies characterized by aberrant immune activation. Adoptive transfer of ex vivo expanded autologous Tregs continues to progress through mid- to late-phase clinical trials in several disease spaces and has generated promising preliminary safety and efficacy signals to date. However, the practicalities of this strategy outside of the clinical trial setting remain challenging. Here, we review the current landscape of regulatory T-cell therapy, considering emergent approaches and technologies presenting novel ways to engage Tregs, and reflect on the progress necessary to deliver their therapeutic potential to patients.

Spatial transcriptomic characterization of COVID-19 pneumonitis identifies immune circuits related to tissue injury

Severe lung damage resulting from COVID-19 involves complex interactions between diverse populations of immune and stromal cells. In this study, we used a spatial transcriptomics approach to delineate the cells, pathways, and genes present across the spectrum of histopathological damage in COVID-19-affected lung tissue. We applied correlation network-based approaches to deconvolve gene expression data from 46 areas of interest covering more than 62,000 cells within well-preserved lung samples from 3 patients. Despite substantial interpatient heterogeneity, we discovered evidence for a common immune-cell signaling circuit in areas of severe tissue that involves crosstalk between cytotoxic lymphocytes and pro-inflammatory macrophages. Expression of IFNG by cytotoxic lymphocytes was associated with induction of chemokines, including CXCL9, CXCL10, and CXCL11, which are known to promote the recruitment of CXCR3+ immune cells. The TNF superfamily members BAFF (TNFSF13B) and TRAIL (TNFSF10) were consistently upregulated in the areas with severe tissue damage. We used published spatial and single-cell SARS-CoV-2 data sets to validate our findings in the lung tissue from additional cohorts of patients with COVID-19. The resulting model of severe COVID-19 immune-mediated tissue pathology may inform future therapeutic strategies.

Barriers to Treg therapy in Europe: From production to regulation

There has been an increased interest in cell based therapies for a range of medical conditions in the last decade. This explosion in novel therapeutics research has led to the development of legislation specifically focused on cell and gene based therapies. In Europe, the European medicines agency (EMA) designates any medicines for human use which are based on genes, tissues, or cells as advanced therapy medicinal products or advanced therapy medicinal products (ATMPs). In this article we discuss the hurdles to widespread adoption of ATMPs in Europe, with a focus on regulatory T cells (Tregs). There are numerous barriers which must be overcome before mainstream adoption of Treg therapy becomes a reality. The source of the cells, whether to use autologous or allogenic cells, and the methods through which they are isolated and expanded, must all meet strict good manufacturing practice (GMP) standards to allow use of the products in humans. GMP compliance is costly, with the equipment and reagents providing a significant cost barrier and requiring specialized facilities and personnel. Conforming to the regulations set centrally by the EMA is difficult, and the different interpretations of the regulations across the various member states further complicates the regulatory approval process. The end products then require a complex and robust distribution network to ensure timely delivery of potentially life saving treatments to patients. In a European market whose logistics networks have been hammered by COVID and Brexit, ensuring rapid and reliable delivery systems is a more complex task than ever. In this article we will examine the impact of these barriers on the development and adoption of Tregs in Europe, and potential approaches which could facilitate more widespread use of Tregs, instead of its current concentration in a few very specialized centers.

A GMP Protocol for the Manufacture of Tregs for Clinical Application

Infusion of regulatory T cells is a promising therapeutic strategy in organ transplantation to modulate the immune system, prevent rejection, minimize the need for pharmaceutical immunosuppression, and improve long-term transplant outcomes. Here we describe a GMP-compliant method we have used for the manufacture of ex vivo expanded autologous regulatory T cells for use in clinical trials.

Low dose interleukin-2 selectively expands circulating regulatory T cells but fails to promote liver allograft tolerance in humans

BACKGROUND & AIMS

CD4+CD25+Foxp3+ regulatory T cells (Tregs) are essential to maintain immunological tolerance and have been shown to promote liver allograft tolerance in both rodents and humans. Low-dose IL-2 (LDIL-2) can expand human endogenous circulating Tregs in vivo, but its role in suppressing antigen-specific responses and promoting Treg trafficking to the sites of inflammation is unknown. Likewise, whether LDIL-2 facilitates the induction of allograft tolerance has not been investigated in humans.

METHODS

We conducted a clinical trial in stable liver transplant recipients 2-6 years post-transplant to determine the capacity of LDIL-2 to suppress allospecific immune responses and allow for the complete discontinuation of maintenance immunosuppression (ClinicalTrials.gov NCT02949492). One month after LDIL-2 was initiated, those exhibiting at least a 2-fold increase in circulating Tregs gradually discontinued immunosuppression over a 4-month period while continuing LDIL-2 for a total treatment duration of 6 months.

RESULTS

All participants achieved a marked and sustained increase in circulating Tregs. However, this was not associated with the preferential expansion of donor-reactive Tregs and did not promote the accumulation of intrahepatic Tregs. Furthermore, LDIL-2 induced a marked IFNγ-orchestrated transcriptional response in the liver even before immunosuppression weaning was initiated. The trial was terminated after the first 6 participants failed to reach the primary endpoint owing to rejection requiring reinstitution of immunosuppression.

CONCLUSIONS

The expansion of circulating Tregs in response to LDIL-2 is not sufficient to control alloimmunity and to promote liver allograft tolerance, due, at least in part, to off-target effects that increase liver immunogenicity. Our trial provides unique insight into the mechanisms of action of immunomodulatory therapies such as LDIL-2 and their limitations in promoting alloantigen-specific effects and immunological tolerance.

CLINICAL TRIALS REGISTRATION

The study is registered at ClinicalTrials.gov (NCT02949492).

IMPACT AND IMPLICATIONS

The administration of low-dose IL-2 is an effective way of increasing the number of circulating regulatory T cells (Tregs), an immunosuppressive lymphocyte subset that is key for the establishment of immunological tolerance, but its use to promote allograft tolerance in the setting of clinical liver transplantation had not been explored before. In liver transplant recipients on tacrolimus monotherapy, low-dose IL-2 effectively expanded circulating Tregs but did not increase the number of Tregs with donor specificity, nor did it promote their trafficking to the transplanted liver. Low-dose IL-2 did not facilitate the discontinuation of tacrolimus and elicited, as an off-target effect, an IFNγ-orchestrated inflammatory response in the liver that resembled T cell-mediated rejection. These results, supporting an unexpected role for IL-2 in regulating the immunogenicity of the liver, highlight the need to carefully evaluate systemic immunoregulatory strategies with investigations that are not restricted to the blood compartment and involve target tissues such as the liver.

Pediatric Casualties in Terrorist Attacks: A Semi-Quantitative Analysis of Global Events

BACKGROUND

Terrorism remains a major threat and concern in many countries around the world. Pediatric populations represent approximately 30% of the world population, and in the event of a terrorist attack, can either be primary targets, to include the possibility of abduction, or unintended victims. They are unique in their vulnerabilities and, therefore, require special consideration.

METHODS

This study is a semi-quantitative, epidemiological analysis of all terrorism-related pediatric fatalities and injuries sustained from 1970-2019. Data collection was performed using a retrospective database search through the Global Terrorism Database (GTD). Summaries of events including search terms associated with pediatric population were individually reviewed and those describing the deaths, injuries, or abductions were tallied.

RESULTS

Of the over 200,000 terror events, 2,302 events met inclusion criteria. This represented 1.14% of total events which involved death, injury, or abduction. Of 2,032 events, a total of 2,275 pediatric fatal injuries (FI) were recorded, as well as 2,280 pediatric non-fatal injuries (NFI). The most common weapons used in all attacks involving the pediatric population were explosives (1,539 [66.8%]), firearms (543 [23.5%]), other (169 [7.3%]), and melee (83 [3.6%]). A total of 275 of the 2,032 events were related to abductions, with 71 cases involving the abduction of 10 individuals or more.

CONCLUSION

Pediatric casualties in terrorist events represent a small proportion of overall victims. However, it should be understood that the pediatric population has unique vulnerabilities, and when directly impacted by terrorism, can have long-term physical and psychosocial sequelae, as well as a devastating emotional impact on the community.

Predicting mortality and morbidity in emergency general surgery patients in a Jordanian Tertiary Medical Center: a retrospective validation study of the Emergency Surgery Score (ESS)

OBJECTIVE

The Emergency Surgery Score (ESS) is a predictive tool used to assess morbidity and mortality rates in patients undergoing emergent surgery. This study explores the ESS's predictive ability and reliability in the Jordanian surgical population.

DESIGN

A retrospective validation study.

SETTING

A tertiary hospital in Jordan.

PARTICIPANTS

A database was created including patients who underwent emergent surgery in King Abdullah University Hospital from January 2017 to June 2021.

PRIMARY AND SECONDARY OUTCOME MEASURES

Relevant preoperative, intraoperative and postoperative variables were retrospectively and systematically gathered, and the ESS was calculated for each patient accordingly. In addition, a multivariable logistic regression analysis was performed to assess the correlations between the ESS and postoperative mortality and morbidity along with intensive care unit (ICU) admissions.

RESULTS

Out of total of 1452 patients evaluated, 1322 patients were enrolled based on inclusion and exclusion criteria. The mean age of the population was 47.9 years old. 91.9% of the patients were admitted to the surgical ward through the emergency department, while the rest were referred from inpatient and outpatient facilities. The mortality and postoperative complication rates were 3.9% and 13.5%, respectively. Mortality rates increased as the ESS score gradually increased, and the ESS was evaluated as a strong predictor with a c-statistic value of 0.842 (95% CI 0.743 to 0.896). The postoperative complication and ICU admission rate also increased with reciprocal rises in the ESS. They were also evaluated as accurate predictors with a c-statistic value of 0.724 (95% CI 0.682 to 0.765) and a c-statistic value of 0.825 (95% CI 0.784 to 0.866), respectively.

CONCLUSION

The ESS is a robust, accurate predictor of postoperative mortality and morbidity of emergency general surgery patients. Furthermore, it is an all-important tool to enhance emergency general surgery practices, in terms of mitigating risk, quality of care measures and patient counselling.

Neutrophil Extracellular Traps, Local IL-8 Expression, and Cytotoxic T-Lymphocyte Response in the Lungs of Patients With Fatal COVID-19

BACKGROUND

Excessive inflammation is pathogenic in the pneumonitis associated with severe COVID-19. Neutrophils are among the most abundantly present leukocytes in the inflammatory infiltrates and may form neutrophil extracellular traps (NETs) under the local influence of cytokines. NETs constitute a defense mechanism against bacteria, but have also been shown to mediate tissue damage in a number of diseases.

RESEARCH QUESTION

Could NETs and their tissue-damaging properties inherent to neutrophil-associated functions play a role in the respiratory failure seen in patients with severe COVID-19, and how does this relate to the SARS-CoV-2 viral loads, IL-8 (CXCL8) chemokine expression, and cytotoxic T-lymphocyte infiltrates?

STUDY DESIGN AND METHODS

Sixteen lung biopsy samples obtained immediately after death were analyzed methodically as exploratory and validation cohorts. NETs were analyzed quantitatively by multiplexed immunofluorescence and were correlated with local levels of IL-8 messenger RNA (mRNA) and the density of CD8+ T-cell infiltration. SARS-CoV-2 presence in tissue was quantified by reverse-transcriptase polymerase chain reaction and immunohistochemistry analysis.

RESULTS

NETs were found in the lung interstitium and surrounding the bronchiolar epithelium with interindividual and spatial heterogeneity. NET density did not correlate with SARS-CoV-2 tissue viral load. NETs were associated with local IL-8 mRNA levels. NETs were also detected in pulmonary thrombi and in only one of eight liver tissues. NET focal presence correlated negatively with CD8+ T-cell infiltration in the lungs.

INTERPRETATION

Abundant neutrophils undergoing NETosis are found in the lungs of patients with fatal COVID-19, but no correlation was found with viral loads. The strong association between NETs and IL-8 points to this chemokine as a potentially causative factor. The function of cytotoxic T-lymphocytes in the immune responses against SARS-CoV-2 may be interfered with by the presence of NETs.

Engineered human cytokine/antibody fusion proteins expand regulatory T cells and confer autoimmune disease protection

Low-dose human interleukin-2 (hIL-2) treatment is used clinically to treat autoimmune disorders due to the cytokine's preferential expansion of immunosuppressive regulatory T cells (Tregs). However, off-target immune cell activation and short serum half-life limit the clinical potential of IL-2 treatment. Recent work showed that complexes comprising hIL-2 and the anti-hIL-2 antibody F5111 overcome these limitations by preferentially stimulating Tregs over immune effector cells. Although promising, therapeutic translation of this approach is complicated by the need to optimize dosing ratios and by the instability of the cytokine/antibody complex. We leverage structural insights to engineer a single-chain hIL-2/F5111 antibody fusion protein, termed F5111 immunocytokine (IC), which potently and selectively activates and expands Tregs. F5111 IC confers protection in mouse models of colitis and checkpoint inhibitor-induced diabetes mellitus. These results provide a roadmap for IC design and establish a Treg-biased immunotherapy that could be clinically translated for autoimmune disease treatment.

Joining Forces in Basic Science: ITS Meeting 2.0

The second International Transplant Science (ITS) meeting jointly organized by the European Society for Organ Transplantation (ESOT), the American Society of Transplantation (AST), and The Transplantation Society (TTS) took place in May 2022 in one of Europe's most iconic cities: Berlin, Germany. The ITS meeting 2022 was designed to serve as an international platform for scientific discussions on the latest ground-breaking discoveries in the field, while providing an excellent opportunity to present cutting-edge research to the scientific community. We think this is fundamental for the exchange of new ideas and establishment of collaborative work between advanced transplant experts, young professionals and early-stage researchers and students. Scientific sessions tackled hot topics in transplantation such as mechanisms of tolerance, biomarkers, big data and artificial intelligence. Our educational pre-meeting focused on the breakthrough and challenges in single-cell multimodal omics. The program included panel discussions illuminating various topics concerning conflicts and problems related to gender, such as challenges for female scientists. Attendees returned to their institutes with not only profound knowledge of the latest discoveries, technologies, and concepts in basic and translational science, but also inspired and excited after discussions and networking sessions with fellow scientists which have been duly missed during the pandemic.

No statistically significant difference in long term scarring outcomes of pediatric burns patients treated surgically vs. those treated conservatively

Introduction

Paediatric burns are a common clinical presentation. The long-term scar outcomes in paediatric burns patients are relatively unknown as most are discharged after 6 weeks follow up, apart from the small number that are followed up by scar services depending on geographical availability. We aimed to determine whether the long-term scarring outcomes are significantly different in those who had surgical treatment with Versajet® debridement and Biobrane®, vs. those treated conservatively with non-adherent Mepitel® and Acticoat® dressings, in a cohort of paediatric burns patients.

Methods

The parents of all paediatric burns patients admitted to Stoke Mandeville Hospital from October 2014 to September 2017 were contacted by telephone to fill in the paediatric Brisbane Burn Scar Impact Profile (BBSIP), the only patient reported outcome measure (PROM) specifically aimed at children. The results from the questionnaires underwent statistical analysis to see if there was a significant difference in questionnaire scores between children treated surgically vs. those treated conservatively.

Results

A total of 107 children were admitted in the timeframe, responses were received from 34 patients with 13 having been treated surgically and 21 having been treated conservatively. In all 58 questions that make up the BBSIP, there was no statistically significant difference observed in the scores of those treated surgically vs. those treated conservatively. For 31 questions on the BBSIP, the lowest score indicating the best outcome was observed in all patients in both groups.

Discussion

Surgical management for burns is always the last resort. Our results could be interpreted to suggest clinicians need not fear the longer-term impact a scar may have when deciding whether to treat a paediatric burns patient surgically or conservatively. This study is the first to assess longer-term scar outcomes using the BBSIP. A larger data set and comparison with other burn units in the UK may help to provide more information on scar outcomes between different methods of surgical and conservative treatment. We found no statistically significant difference in the long-term scar outcomes as assessed by the BBSIP in paediatric burn patients treated with Versajet® debridement and Biobrane®, vs. those treated conservatively with non-adherent Mepitel® and Acticoat® dressings.

Hypoxia inducible factors regulate infectious SARS-CoV-2, epithelial damage and respiratory symptoms in a hamster COVID-19 model

Understanding the host pathways that define susceptibility to Severe-acute-respiratory-syndrome-coronavirus-2 (SARS-CoV-2) infection and disease are essential for the design of new therapies. Oxygen levels in the microenvironment define the transcriptional landscape, however the influence of hypoxia on virus replication and disease in animal models is not well understood. In this study, we identify a role for the hypoxic inducible factor (HIF) signalling axis to inhibit SARS-CoV-2 infection, epithelial damage and respiratory symptoms in the Syrian hamster model. Pharmacological activation of HIF with the prolyl-hydroxylase inhibitor FG-4592 significantly reduced infectious virus in the upper and lower respiratory tract. Nasal and lung epithelia showed a reduction in SARS-CoV-2 RNA and nucleocapsid expression in treated animals. Transcriptomic and pathological analysis showed reduced epithelial damage and increased expression of ciliated cells. Our study provides new insights on the intrinsic antiviral properties of the HIF signalling pathway in SARS-CoV-2 replication that may be applicable to other respiratory pathogens and identifies new therapeutic opportunities.

Dampened Inflammatory Signalling and Myeloid-Derived Suppressor-Like Cell Accumulation Reduces Circulating Monocytic HLA-DR Density and May Associate With Malignancy Risk in Long-Term Renal Transplant Recipients

Background

Malignancy is a major cause of morbidity and mortality in transplant recipients. Identification of those at highest risk could facilitate pre-emptive intervention such as reduction of immunosuppression. Reduced circulating monocytic HLA-DR density is a marker of immune depression in the general population and associates with poorer outcome in critical illness. It has recently been used as a safety marker in adoptive cell therapy trials in renal transplantation. Despite its potential as a marker of dampened immune responses, factors that impact upon monocytic HLA-DR density and the long-term clinical sequelae of this have not been assessed in transplant recipients.

Methods

A cohort study of stable long-term renal transplant recipients was undertaken. Serial circulating monocytic HLA-DR density and other leucocyte populations were quantified by flow cytometry. Gene expression of monocytes was performed using the Nanostring nCounter platform, and 13-plex cytokine bead array used to quantify serum concentrations. The primary outcome was malignancy development during one-year follow-up. Risk of malignancy was calculated by univariate and multivariate proportionate hazards modelling with and without adjustment for competing risks.

Results

Monocytic HLA-DR density was stable in long-term renal transplant recipients (n=135) and similar to non-immunosuppressed controls (n=29), though was suppressed in recipients receiving prednisolone. Decreased mHLA-DRd was associated with accumulation of CD14+CD11b+CD33+HLA-DRlo monocytic myeloid-derived suppressor-like cells. Pathway analysis revealed downregulation of pathways relating to cytokine and chemokine signalling in monocytes with low HLA-DR density; however serum concentrations of major cytokines did not differ between these groups. There was an independent increase in malignancy risk during follow-up with decreased HLA-DR density.

Conclusions

Dampened chemokine and cytokine signalling drives a stable reduction in monocytic HLA-DR density in long-term transplant recipients and associates with subsequent malignancy risk. This may function as a novel marker of excess immunosuppression. Further study is needed to understand the mechanism behind this association.

SARS-CoV-2-Specific T Cell Responses Are Not Associated with Protection against Reinfection in Hemodialysis Patients

Significance Statement

Patients on hemodialysis (HD) are vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and mount poor neutralizing antibody responses after two-dose vaccination. Although serological responses have been associated with reduced rates of reinfection, the relationship between cellular immunogenicity and protection has not been established. We report, for the first time, high incidence of reinfection in patients on HD who are vaccine naive (25%), which identifies that T cell responses do not predict protection against reinfection. Instead, patients on HD who went on to become reinfected had mounted highly variable and sometimes robust proliferative T cell responses to a broad array of SARS-CoV-2 peptide pools during the primary infection. The understanding that SARS-CoV-2–specific T cell responses are not predictive of protection against future infection will be a critical issue when measuring clinical efficacy of vaccination in these vulnerable cohorts, particularly when facing rapidly emerging variants of concern.

A Systematic Review Comparing Animal and Human Scarring Models

Introduction

A reproducible, standardised model for cutaneous scar tissue to assess therapeutics is crucial to the progress of the field. A systematic review was performed to critically evaluate scarring models in both animal and human research.

Method

All studies in which cutaneous scars are modelling in animals or humans were included. Models that were focused on the wound healing process or those in humans with scars from an existing injury were excluded. Ovid Medline^® was searched on 25 February 2019 to perform two near identical searches; one aimed at animals and the other aimed at humans. Two reviewers independently screened the titles and abstracts for study selection. Full texts of potentially suitable studies were then obtained for analysis.

Results

The animal kingdom search yielded 818 results, of which 71 were included in the review. Animals utilised included rabbits, mice, pigs, dogs and primates. Methods used for creating scar tissue included sharp excision, dermatome injury, thermal injury and injection of fibrotic substances. The search for scar assessment in humans yielded 287 results, of which 9 met the inclusion criteria. In all human studies, sharp incision was used to create scar tissue. Some studies focused on patients before or after elective surgery, including bilateral breast reduction, knee replacement or midline sternotomy.

Discussion

The rabbit ear scar model was the most popular tool for scar research, although pigs produce scar tissue which most closely resembles that of humans. Immunodeficient mouse models allow for in vivo engraftment and study of human scar tissue, however, there are limitations relating to the systemic response to these xenografts. Factors that determine the use of animals include cost of housing requirements, genetic traceability, and ethical concerns. In humans, surgical patients are often studied for scarring responses and outcomes, but reproducibility and patient factors that impact healing can limit interpretation. Human tissue use in vitro may serve as a good basis to rapidly screen and assess treatments prior to clinical use, with the advantage of reduced cost and setup requirements.

Transplantation Without Overimmunosuppression (TWO) study protocol: a phase 2b randomised controlled single-centre trial of regulatory T cell therapy to facilitate immunosuppression reduction in living donor kidney transplant recipients

INTRODUCTION

Regulatory T cell (Treg) therapy has been demonstrated to facilitate long-term allograft survival in preclinical models of transplantation and may permit reduction of immunosuppression and its associated complications in the clinical setting. Phase 1 clinical trials have shown Treg therapy to be safe and feasible in clinical practice. Here we describe a protocol for the TWO study, a phase 2b randomised control trial of Treg therapy in living donor kidney transplant recipients that will confirm safety and explore efficacy of this novel treatment strategy.

METHODS AND ANALYSIS

60 patients will be randomised on a 1:1 basis to Treg therapy (TR001) or standard clinical care (control). Patients in the TR001 arm will receive an infusion of autologous polyclonal ex vivo expanded Tregs 5 days after transplantation instead of standard monoclonal antibody induction. Maintenance immunosuppression will be reduced over the course of the post-transplant period to low-dose tacrolimus monotherapy. Control participants will receive a standard basiliximab-based immunosuppression regimen with long-term tacrolimus and mycophenolate mofetil immunosuppression. The primary endpoint is biopsy proven acute rejection over 18 months; secondary endpoints include immunosuppression burden, chronic graft dysfunction and drug-related complications.

ETHICS AND DISSEMINATION

Ethical approval has been provided by the National Health Service Health Research Authority South Central-Oxford A Research Ethics Committee (reference 18/SC/0054). The study also received authorisation from the UK Medicines and Healthcare products Regulatory Agency and is being run in accordance with the principles of Good Clinical Practice, in collaboration with the registered trials unit Oxford Clinical Trials Research Unit. Results from the TWO study will be published in peer-reviewed scientific/medical journals and presented at scientific/clinical symposia and congresses.

TRIAL REGISTRATION NUMBER

ISRCTN: 11038572; Pre-results.

TNFR2 blockade of regulatory T cells unleashes an antitumor immune response after hematopoietic stem-cell transplantation

Background

Targeting immune checkpoints that inhibit antitumor immune responses has emerged as a powerful new approach to treat cancer. We recently showed that blocking the tumor necrosis factor receptor-type 2 (TNFR2) pathway induces the complete loss of the protective function of regulatory T cells (Tregs) in a model of graft-versus-host disease (GVHD) prevention that relies on Treg-based cell therapy. Here, we tested the possibility of amplifying the antitumor response by targeting TNFR2 in a model of tumor relapse following hematopoietic stem-cell transplantation, a clinical situation for which the need for efficient therapeutic options is still unmet.

Method

We developed appropriate experimental conditions that mimic patients that relapsed from their initial hematological malignancy after hematopoietic stem-cell transplantation. This consisted of defining in allogeneic bone marrow transplantation models developed in mice, the maximum number of required tumor cells and T cells to infuse into recipient mice to develop a model of tumor relapse without inducing GVHD. We next evaluated whether anti-TNFR2 treatment could trigger alloreactivity and consequently antitumor immune response. In parallel, we also studied the differential expression of TNFR2 on T cells including Treg from patients in post-transplant leukemia relapse and in patients developing GVHD.

Results

Using experimental conditions in which neither donor T cells nor TNFR2-blocking antibody per se have any effect on tumor relapse, we observed that the coadministration of a suboptimal number of T cells and an anti-TNFR2 treatment can trigger alloreactivity and subsequently induce a significant antitumor effect. This was associated with a reduced percentage of activated CD4⁺ and CD8⁺ Tregs. Importantly, human Tregs over-expressed TNFR2 relative to conventional T cells in healthy donors and in patients experiencing leukemia relapse or cortico-resistant GVHD after hematopoietic stem cell transplantation.

Conclusions

These results highlight TNFR2 as a new target molecule for the development of immunotherapies to treat blood malignancy relapse, used either directly in grafted patients or to enhance donor lymphocyte infusion strategies. More widely, they open the door for new perspectives to amplify antitumor responses against solid cancers by directly targeting Tregs through their TNFR2 expression.

A non-coding RNA balancing act: miR-346-induced DNA damage is limited by the long non-coding RNA NORAD in prostate cancer

BACKGROUND

miR-346 was identified as an activator of Androgen Receptor (AR) signalling that associates with DNA damage response (DDR)-linked transcripts in prostate cancer (PC). We sought to delineate the impact of miR-346 on DNA damage, and its potential as a therapeutic agent.

METHODS

RNA-IP, RNA-seq, RNA-ISH, DNA fibre assays, in vivo xenograft studies and bioinformatics approaches were used alongside a novel method for amplification-free, single nucleotide-resolution genome-wide mapping of DNA breaks (INDUCE-seq).

RESULTS

miR-346 induces rapid and extensive DNA damage in PC cells - the first report of microRNA-induced DNA damage. Mechanistically, this is achieved through transcriptional hyperactivation, R-loop formation and replication stress, leading to checkpoint activation and cell cycle arrest. miR-346 also interacts with genome-protective lncRNA NORAD to disrupt its interaction with PUM2, leading to PUM2 stabilisation and its increased turnover of DNA damage response (DDR) transcripts. Confirming clinical relevance, NORAD expression and activity strongly correlate with poor PC clinical outcomes and increased DDR in biopsy RNA-seq studies. In contrast, miR-346 is associated with improved PC survival. INDUCE-seq reveals that miR-346-induced DSBs occur preferentially at binding sites of the most highly-transcriptionally active transcription factors in PC cells, including c-Myc, FOXA1, HOXB13, NKX3.1, and importantly, AR, resulting in target transcript downregulation. Further, RNA-seq reveals widespread miR-346 and shNORAD dysregulation of DNA damage, replication and cell cycle processes. NORAD drives target-directed miR decay (TDMD) of miR-346 as a novel genome protection mechanism: NORAD silencing increases mature miR-346 levels by several thousand-fold, and WT but not TDMD-mutant NORAD rescues miR-346-induced DNA damage. Importantly, miR-346 sensitises PC cells to DNA-damaging drugs including PARP inhibitor and chemotherapy, and induces tumour regression as a monotherapy in vivo, indicating that targeting miR-346:NORAD balance is a valid therapeutic strategy.

CONCLUSIONS

A balancing act between miR-346 and NORAD regulates DNA damage and repair in PC. miR-346 may be particularly effective as a therapeutic in the context of decreased NORAD observed in advanced PC, and in transcriptionally-hyperactive cancer cells.

Variance Analysis of Expatriate Pre-Hospital Provider Training in Bahrain

Introduction

The absence of local Emergency Medical Services (EMS) educational programs in Bahrain has given rise to an EMS workforce comprised predominantly of expatriate personnel with varying educational backgrounds that require further training before being licensed as EMS providers in Bahrain.

Methods

A qualitative variance analysis was performed comparing desired core competencies for EMS practice in neighbouring Saudi Arabia, used as a comparator for Bahrain, with core competencies extracted from national curricula of the major countries from which expatriate providers originate.

Results

Major core competencies not covered by the expatriate providers’ curricula were identified as follows: working in an autonomous environment, requiring different critical thinking and decision-making skills, assessment and treatment during transportation, disaster response, EMS knowledge base, and coping with the different stressors of the prehospital environment.

Conclusion

These results can form the basis for additional customized training programs for expatriate EMS providers working in Bahrain, with the goal of improving and standardizing EMS care in the country.

Hermansky-Pudlak syndrome type 1 causes impaired anti-microbial immunity and inflammation due to dysregulated immunometabolism

Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking. The mechanism for Crohn's disease-like inflammation, lung fibrosis, and macrophage lipid accumulation in these patients remains enigmatic. The aim of this study is to understand the cellular basis of inflammation in HPS-1. We performed mass cytometry, proteomic and transcriptomic analyses to investigate peripheral blood cells and serum of HPS-1 patients. Using spatial transcriptomics, granuloma-associated signatures in the tissue of an HPS-1 patient with granulomatous colitis were dissected. In vitro studies were conducted to investigate anti-microbial responses of HPS-1 patient macrophages and cell lines. Monocytes of HPS-1 patients exhibit an inflammatory phenotype associated with dysregulated TNF, IL-1α, OSM in serum, and monocyte-derived macrophages. Inflammatory macrophages accumulate in the intestine and granuloma-associated macrophages in HPS-1 show transcriptional signatures suggestive of a lipid storage and metabolic defect. We show that HPS1 deficiency leads to an altered metabolic program and Rab32-dependent amplified mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic mechanism translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. Rab32-mediated mTOR signaling acts as an immuno-metabolic checkpoint, adding to the evidence that defective bioenergetics can drive hampered anti-microbial activity and contribute to inflammation.

Freezing Medium Containing 5% DMSO Enhances the Cell Viability and Recovery Rate After Cryopreservation of Regulatory T Cell Products ex vivo and in vivo

Cell therapies have significant therapeutic potential in diverse fields including regenerative medicine, transplantation tolerance, and autoimmunity. Within these fields, regulatory T cells (Treg) have been deployed to ameliorate aberrant immune responses with great success. However, translation of the cryopreservation strategies employed for other cell therapy products, such as effector T cell therapies, to Treg therapies has been challenging. The lack of an optimized cryopreservation strategy for Treg products presents a substantial obstacle to their broader application, particularly as administration of fresh cells limits the window available for sterility and functional assessment. In this study, we aimed to develop an optimized cryopreservation strategy for our CD4+CD25+Foxp3+ Treg clinical product. We investigate the effect of synthetic or organic cryoprotectants including different concentrations of DMSO on Treg recovery, viability, phenotype, cytokine production, suppressive capacity, and in vivo survival following GMP-compliant manufacture. We additionally assess the effect of adding the extracellular cryoprotectant polyethylene glycol (PEG), or priming cellular expression of heat shock proteins as strategies to improve viability. We find that cryopreservation in serum-free freezing medium supplemented with 10% human serum albumin and 5% DMSO facilitates improved Treg recovery and functionality and supports a reduced DMSO concentration in Treg cryopreservation protocols. This strategy may be easily incorporated into clinical manufacture protocols for future studies.

Towards regulatory cellular therapies in solid organ transplantation

Organ transplantation is a modern medical success story. However, since its inception it has been limited by the need for pharmacological immunosuppression. Regulatory cellular therapies offer an attractive solution to these challenges by controlling transplant alloresponses through multiple parallel suppressive mechanisms. A number of cell types have seen an accelerated development into human trials and are now on the threshold of a long-awaited breakthrough in personalized transplant therapeutics. Here we assess recent developments with a focus on the most likely candidates, some of which have already facilitated successful immunosuppression withdrawal in early clinical trials. We propose that this may constitute a promising approach in clinical transplantation but also evaluate outstanding issues in the field, providing cause for cautious optimism.

Identification of LZTFL1 as a candidate effector gene at a COVID-19 risk locus

The severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) disease (COVID-19) pandemic has caused millions of deaths worldwide. Genome-wide association studies identified the 3p21.31 region as conferring a twofold increased risk of respiratory failure. Here, using a combined multiomics and machine learning approach, we identify the gain-of-function risk A allele of an SNP, rs17713054G>A, as a probable causative variant. We show with chromosome conformation capture and gene-expression analysis that the rs17713054-affected enhancer upregulates the interacting gene, leucine zipper transcription factor like 1 (LZTFL1). Selective spatial transcriptomic analysis of lung biopsies from patients with COVID-19 shows the presence of signals associated with epithelial-mesenchymal transition (EMT), a viral response pathway that is regulated by LZTFL1. We conclude that pulmonary epithelial cells undergoing EMT, rather than immune cells, are likely responsible for the 3p21.31-associated risk. Since the 3p21.31 effect is conferred by a gain-of-function, LZTFL1 may represent a therapeutic target.