Targeting human plasmacytoid dendritic cells through BDCA2 prevents skin inflammation and fibrosis in a novel xenotransplant mouse model of scleroderma

OBJECTIVES

Plasmacytoid dendritic cells (pDC) have been implicated in the pathogenesis of autoimmune diseases, such as scleroderma (SSc). However, this has been derived from indirect evidence using ex vivo human samples or mouse pDC in vivo. We have developed human-specific pDC models to directly identify their role in inflammation and fibrosis, as well as attenuation of pDC function with BDCA2-targeting to determine its therapeutic application.

METHODS

RNAseq of human pDC with TLR9 agonist ODN2216 and humanised monoclonal BDCA2 antibody, CBS004. Organotypic skin rafts consisting of fibroblasts and keratinocytes were stimulated with supernatant from TLR9-stimulated pDC and with CBS004. Human pDC were xenotransplanted into Nonobese diabetic/severe combined immunodeficiency (NOD SCID) mice treated with Aldara (inflammatory model), or bleomycin (fibrotic model) with CBS004 or human IgG control. Skin punch biopsies were used to assess gene and protein expression.

RESULTS

RNAseq shows TLR9-induced activation of human pDC goes beyond type I interferon (IFN) secretion, which is functionally inactivated by BDCA2-targeting. Consistent with these findings, we show that BDCA2-targeting of pDC can completely suppress in vitro skin IFN-induced response. Most importantly, xenotransplantation of human pDC significantly increased in vivo skin IFN-induced response to TLR agonist and strongly enhanced fibrotic and immune response to bleomycin compared with controls. In these contexts, BDCA2-targeting suppressed human pDC-specific pathological responses.

CONCLUSIONS

Our data indicate that human pDC play a key role in inflammation and immune-driven skin fibrosis, which can be effectively blocked by BDCA2-targeting, providing direct evidence supporting the development of attenuation of pDC function as a therapeutic application for SSc.

Global Quality Standard for Identification and Management of Severe Asthma

INTRODUCTION

Severe asthma is a debilitating, life-threatening disease associated with substantial global morbidity, mortality, and health care resource utilization. Patients may not receive guideline-directed medical care for severe asthma. Moreover, viable precision-based assessment tools and newer preventive therapies that can reduce the frequency of exacerbations and associated functional impact are underused. As a result, high rates of poorly controlled severe asthma persist, and patient health-related quality of life suffers.

METHODS

In 2019, the Improve Access to Better Care Task Force of the PRECISION Steering Committee set out to develop a global template on quality standards for severe asthma care to support improved access to and delivery of quality care. This Quality Standard is grounded in the vast body of published evidence available for severe asthma care, published clinical guidelines (i.e., from the Global Initiative for Asthma in 2019 and the European Respiratory Society/American Thoracic Society in 2014), and the 2018 PRECISION-supported Charter to Improve Patient Care in Severe Asthma.

RESULTS

The Quality Standard developed emphasizes four key elements aimed at optimizing clinical care and outcomes in severe asthma: (1) organization of services, (2) timely identification and referral for suspected severe asthma, (3) specialized assessment and management of severe asthma to optimize outcomes, and (4) patient-centric care and shared decision-making that is reflective of the patient's expectations, priorities, and values. Four key Quality Statements are provided, along with quality metrics and strategies for local adaptation to optimize implementation.

CONCLUSION

This Global Quality Standard is intended to mobilize policymakers, health care providers, and patient advocacy groups to build consensus on the definition and expectations of quality care in severe asthma, to promote patient-centric care, to identify gaps in care and areas for improvement, and systematically implement improvement measures and outcomes and to reduce the burden of illness for patients with severe asthma.

Management of Fracture Risk in Patients with Chronic Obstructive Pulmonary Disease (COPD): Building a UK Consensus Through Healthcare Professional and Patient Engagement

Introduction

Osteoporosis and bone fractures are common in chronic obstructive pulmonary disease (COPD) and contribute significantly to morbidity and mortality. Current national guidance on COPD management recommends addressing bone health in patients, however, does not detail how. This consensus outlines key elements of a structured approach to managing bone health and fracture risk in patients with COPD.

Methods

A systematic approach incorporating multifaceted methodologies included detailed patient and healthcare professional (HCP) surveys followed by a roundtable meeting to reach a consensus on what a pathway would look like.

Results

The surveys revealed that fracture risk was not always assessed despite being recognised as an important aspect of COPD management by HCPs. The majority of the patients also stated they would be receptive to discussing treatment options if found to be at risk of osteoporotic fractures. Limited time and resource allocation were identified as barriers to addressing bone health during consultations. The consensus from the roundtable meeting was that a proactive systematic approach to assessing bone health should be adopted. This should involve using fracture risk assessment tools to identify individuals at risk, investigating secondary causes of osteoporosis if a diagnosis is made and reinforcing non-pharmacological and preventative measures such as smoking cessation, keeping active and pharmacological management of osteoporosis and medicines management of corticosteroid use. Practically, prioritising patients with important additional risk factors, such as previous fragility fractures, older age and long-term oral corticosteroid use for an assessment, was felt required.

Conclusion

There is a need for integrating fracture risk assessment into the COPD pathway. Developing a systematic and holistic approach to addressing bone health is key to achieving this. In tandem, opportunities to disseminate the information and educational resources are also required.

SAT0351 CHEMOKINE PATHWAYS ARE ENRICHED IN PSORIATIC ARTHRITIS (PSA) SKIN LESIONS WITH INCREASED EXPRESSION OF ATYPICAL CHEMOKINE RECEPTOR 2 (ACKR2)

Background:

Skin in people with psoriasis has been comprehensively studied; uninvolved skin has abnormal gene expression. Less is known specifically about skin in PsA, the assumption being that it is identical to psoriasis. Chemokines and ACKR2 are among the upregulated genes in uninvolved psoriasis compared to healthy skin[1]. ACKR2 is a scavenging receptor of inflammatory CC chemokines and has been proposed as a regulator of cutaneous inflammation in psoriasis. It has not been studied in PsA.

Objectives:

To compare the transcriptome of PsA lesional, PsA uninvolved and healthy control skin and evaluate ACKR2 expression in PsA.

Methods:

Biopsies were taken from healthy control (HC) skin and paired lesional and uninvolved skin from patients with PsA. Libraries for bulk RNA sequencing were prepared from polyA selected RNA and sequenced on NovaSeq 6000. Sequencing data were analysed using Searchlight2. ACKR2 mRNA expression was validated by qPCR. RNAscope was used to localise ACKR2 expressing cells and sections were co-stained with podaplanin or stained in serial sections with CD45. Chemokine protein expression in skin was evaluated using Luminex technology.

Results:

Nine HC and 9 paired skin samples from patients with PsA were sequenced. The PsA skin lesions (PsA L) formed a distinct population in the transcriptomic principal component analysis (PCA) plot while HC and PsA uninvolved skin (PsA U) were overlapping. Only 15 genes were differentially expressed between HC and PsA U and none coded for chemokines. There were however significantly upregulated chemokines and receptors in PsA L. Unexpectely, ACKR2 was the 2ndmost upregulated chemokine receptor in PsA L with unchanged expression in PsA U compared with HC (PsA L vs HC log2fold 3.38, p.adj=9.51E-41; PsA L vs PsA U log2fold 3.58, p.adj=3.24E-45; PsA U vs HC log2fold -0.2, p.adj=0.732).

The upregulation of ACKR2 in PsA L and unchanged expression in PsA U was confirmed by qPCR. RNAscope demonstrated strong expression of ACKR2 in the suprabasal layer of the epidermis in PsA L. In HC and PsA U, only occasional ACKR2 positive cells were seen in the epidermis. ACKR2 was expressed in lymphatic vessel walls but was not observed in CD45+ leukocytes.

Provisional skin chemokine protein expression data showed poor correlation between mRNA levels and protein expression for the ACKR2 ligands CCL2, CCL3, CCL7, CCL8, CCL11, CCL13 and CCL22 in HC and PsA U, with negative correlation between ACKR2 mRNA expression and CCL2, CCL8 and CCL11 protein expression. In PsA L, chemokine mRNA correlated with protein expression, but protein expression of chemokine ligands did not correlate with ACKR2 expression.

Conclusion:

This data set shows expected upregulation of chemokines and their receptors in PsA L but relatively unchanged gene expression in PsA U, which contrasts to previous studies in psoriasis. Notably, this study demonstrates a strong upregulation of ACKR2 in keratinocytes in PsA L, with unchanged expression in PsA U. The RNA expression and preliminary protein data suggest that ACKR2 has little effect on the levels of its ligands in PsA skin lesions. However, this study may have missed local effects of ACKR2 in the epidermis.

References:

[1]Singh, M.D., et al.,Elevated expression of the chemokine-scavenging receptor D6 is associated with impaired lesion development in psoriasis.Am J Pathol, 2012.181(4): p. 1158-64.

Acknowledgments:

Funded by the Chief Scientist Office and a private donation to the University of Glasgow. Dr Sabarinadh Chilaka helped to prepare libraries for RNA sequencing.

Disclosure of Interests:

Hanna Johnsson: None declared, John Cole: None declared, Gillian Wilson: None declared, Marieke Pingen: None declared, Fiona McMonagle: None declared, Susan Holmes: None declared, Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB, Stefan Siebert Grant/research support from: BMS, Boehringer Ingelheim, Celgene, GlaxoSmithKline, Janssen, Novartis, Pfizer, UCB, Consultant of: AbbVie, Boehringer Ingelheim, Janssen, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Celgene, Janssen, Novartis, Gerard Graham: None declared

Craniomaxillofacial trauma management in austere and war zone environments - A role for composite tissue allotransplantation?

Facial composite tissue allotransplantation (CTA) is a powerful reconstructive option in cases of extensive severe facial injury and tissue loss. Despite the risk of allograft rejection and the post-operative need for lifelong immunosuppression, facial CTA can be used to restore the normal structural appearance and function of the face. Areas of socioeconomic deprivation and armed conflict zones have a high preponderance of patients with facial burns and other severe injuries. However, these regions often also suffer from lack of resources, expert surgical care and limited facilities. The purpose of this manuscript is to provide a comprehensive review of key principles relevant to facial CTA and their potential applicability in such austere environments. We present a concise literature review of the surgical and immunological basis of facial CTA aimed at the plastic surgery readership, as well as issues surrounding organ transplantations in low- and middle- income countries. We then consider the particular challenges posed by austere settings and countries of active armed conflict and discuss how these may impact the suitability of facial CTA for treating severe facial injuries in these circumstances. Facial CTA is recognised as giving huge benefits for patients with severe facial defects with potentially superior results compared with conventional autograft techniques. Its performance in austere settings is limited by scarce resources and increased pre-, intra- and post- operative risks. However, a case can be made for its use even in these more challenging situations when general organ transplantation compliance and expertise input have been addressed.

Alopecia areata is characterized by dysregulation in systemic type 17 and type 2 cytokines, which may contribute to disease-associated psychological morbidity

BACKGROUND

Alopecia areata (AA) is a common autoimmune disease, causing patchy hair loss that can progress to involve the entire scalp (totalis) or body (universalis). CD8⁺ NKG2D⁺ T cells dominate hair follicle pathogenesis, but the specific mechanisms driving hair loss are not fully understood.

OBJECTIVES

To provide a detailed insight into the systemic cytokine signature associated with AA, and to assess the association between cytokines and depression.

METHODS

We conducted multiplex analysis of plasma cytokines from patients with AA, patients with psoriatic arthritis (PsA) and healthy controls. We used the Hospital Anxiety and Depression Scale (HADS) to assess the occurrence of depression and anxiety in our cohort.

RESULTS

Our analysis identified a systemic inflammatory signature associated with AA, characterized by elevated levels of interleukin (IL)-17A, IL-17F, IL-21 and IL-23 indicative of a type 17 immune response. Circulating levels of the type 2 cytokines IL-33, IL-31 and IL-17E (IL-25) were also significantly increased in AA. In comparison with PsA, AA was associated with higher levels of IL-17F, IL-17E and IL-23. We hypothesized that circulating inflammatory cytokines may contribute to wider comorbidities associated with AA. Our assessment of psychiatric comorbidity in AA using HADS scores showed that 18% and 51% of people with AA experienced symptoms of depression and anxiety, respectively. Using linear regression modelling, we identified that levels of IL-22 and IL-17E are positively and significantly associated with depression.

CONCLUSIONS

Our data highlight changes in both type 17 and type 2 cytokines among people with AA, suggesting that complex systemic cytokine profiles may contribute both to the pathogenesis of AA and to the associated depression. What's already known about this topic? NKG2D⁺ CD8⁺ T cells cause hair loss in alopecia areata (AA) but the immunological mechanisms underlying the disease are not fully understood. AA is associated with changes in levels of interleukin (IL)-6, tumour necrosis factor-α, IL-1β and type 17 cytokines. Psychiatric comorbidity is common among people with AA. What does this study add? People with AA have increased plasma levels of the type 2 cytokines IL-33, IL-31 and IL-17E (IL-25), in addition to the type 17 cytokines IL-17A, IL-21, IL-23 and IL-17F. Levels of IL-17E and IL-22 positively predict depression score. What is the translational message? AA is associated with increased levels of multiple inflammatory cytokines, implicating both type 17- and type 2 immune pathways. Our data indicate that therapeutic strategies for treating AA may need to address the underlying type 17- and type 2 immune dysregulation, rather than focusing narrowly on the CD8⁺ T-cell response. An immunological mechanism might contribute directly to the depression observed in people with AA.

Urogenital symptoms in mitochondrial disease: overlooked and undertreated

Background and purpose

Bowel symptoms are well documented in mitochondrial disease. However, data concerning other pelvic organs is limited. A large case–control study has therefore been undertaken to determine the presence of lower urinary tract symptoms (LUTS) and sexual dysfunction in adults with genetically confirmed mitochondrial disease.

Methods

Adults with genetically confirmed mitochondrial disease and control subjects were recruited from a specialist mitochondrial clinic. The presence and severity of LUTS and their impact on quality of life, in addition to sexual dysfunction and bowel symptoms, were captured using four validated questionnaires. Subgroup analysis was undertaken in patients harbouring the m.3243A>G MT‐TL1 mitochondrial DNA mutation. A subset of patients underwent urodynamic studies to further characterize their LUTS.

Results

Data from 58 patients and 19 controls (gender and age matched) were collected. Adults with mitochondrial disease had significantly more overactive bladder (81.5% vs. 56.3%, P = 0.039) and low stream (34.5% vs. 5.3%, P = 0.013) urinary symptoms than controls. Urodynamic studies in 10 patients confirmed that bladder storage symptoms predominate. Despite high rates of LUTS, none of the patient group was receiving treatment. Female patients and those harbouring the m.3243A>G MT‐TL1 mutation experienced significantly more sexual dysfunction than controls (53.1% vs. 11.1%, P = 0.026, and 66.7% vs. 26.3%, P = 0.011, respectively).

Conclusions

Lower urinary tract symptoms are common but undertreated in adult mitochondrial disease, and female patients and those harbouring the m.3243A>G MT‐TL1 mutation experience sexual dysfunction. Given their impact on quality of life, screening for and treating LUTS and sexual dysfunction in adults with mitochondrial disease are strongly recommended.

Use of bioengineered human commensal gut bacteria-derived microvesicles for mucosal plague vaccine delivery and immunization

Plague caused by the Gram‐negative bacterium, Yersinia pestis, is still endemic in parts of the world today. Protection against pneumonic plague is essential to prevent the development and spread of epidemics. Despite this, there are currently no licensed plague vaccines in the western world. Here we describe the means of delivering biologically active plague vaccine antigens directly to mucosal sites of plague infection using highly stable microvesicles (outer membrane vesicles; OMVs) that are naturally produced by the abundant and harmless human commensal gut bacterium Bacteroides thetaiotaomicron (Bt). Bt was engineered to express major plague protective antigens in its OMVs, specifically Fraction 1 (F1) in the outer membrane and LcrV (V antigen) in the lumen, for targeted delivery to the gastrointestinal (GI) and respiratory tracts in a non‐human primate (NHP) host. Our key findings were that Bt OMVs stably expresses F1 and V plague antigens, particularly the V antigen, in the correct, immunogenic form. When delivered intranasally V‐OMVs elicited substantive and specific immune and antibody responses, both in the serum [immunoglobulin (Ig)G] and in the upper and lower respiratory tract (IgA); this included the generation of serum antibodies able to kill plague bacteria. Our results also showed that Bt OMV‐based vaccines had many desirable characteristics, including: biosafety and an absence of any adverse effects, pathology or gross alteration of resident microbial communities (microbiotas); high stability and thermo‐tolerance; needle‐free delivery; intrinsic adjuvanticity; the ability to stimulate both humoral and cell‐mediated immune responses; and targeting of primary sites of plague infection.