B-cell depletion in autoimmune diseases.

B cells have a pivotal function in the pathogenesis of autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus. In autoimmune disease, B cells orchestrate antigen presentation, cytokine production and autoantibody production, the latter via their differentiation into antibody-secreting plasmablasts and plasma cells. This article addresses the current therapeutic strategies to deplete B cells in order to ameliorate or potentially even cure autoimmune disease. It addresses the main target antigens in the B-cell lineage that are used for therapeutic approaches. Furthermore, it summarises the current evidence for successful treatment of autoimmune disease with monoclonal antibodies targeting B cells and the limitations and challenges of these approaches. Finally, the concept of deep B-cell depletion and immunological reset by chimeric antigen receptor T cells is discussed, as well as the lessons from this approach for better understanding the role of B cells in autoimmune disease.

EULAR recommendations for the management of systemic lupus erythematosus: 2023 update.

OBJECTIVES: To update the EULAR recommendations for the management of systemic lupus erythematosus (SLE) based on emerging new evidence. METHODS: An international Task Force formed the questions for the systematic literature reviews (January 2018-December 2022), followed by formulation and finalisation of the statements after a series of meetings. A predefined voting process was applied to each overarching principle and recommendation. Levels of evidence and strengths of recommendation were assigned, and participants finally provided their level of agreement with each item. RESULTS: The Task Force agreed on 5 overarching principles and 13 recommendations, concerning the use of hydroxychloroquine (HCQ), glucocorticoids (GC), immunosuppressive drugs (ISDs) (including methotrexate, mycophenolate, azathioprine, cyclophosphamide (CYC)), calcineurin inhibitors (CNIs, cyclosporine, tacrolimus, voclosporin) and biologics (belimumab, anifrolumab, rituximab). Advice is also provided on treatment strategies and targets of therapy, assessment of response, combination and sequential therapies, and tapering of therapy. HCQ is recommended for all patients with lupus at a target dose 5 mg/kg real body weight/day, considering the individual's risk for flares and retinal toxicity. GC are used as 'bridging therapy' during periods of disease activity; for maintenance treatment, they should be minimised to equal or less than 5 mg/day (prednisone equivalent) and, when possible, withdrawn. Prompt initiation of ISDs (methotrexate, azathioprine, mycophenolate) and/or biological agents (anifrolumab, belimumab) should be considered to control the disease and facilitate GC tapering/discontinuation. CYC and rituximab should be considered in organ-threatening and refractory disease, respectively. For active lupus nephritis, GC, mycophenolate or low-dose intravenous CYC are recommended as anchor drugs, and add-on therapy with belimumab or CNIs (voclosporin or tacrolimus) should be considered. Updated specific recommendations are also provided for cutaneous, neuropsychiatric and haematological disease, SLE-associated antiphospholipid syndrome, kidney protection, as well as preventative measures for infections, osteoporosis, cardiovascular disease. CONCLUSION: The updated recommendations provide consensus guidance on the management of SLE, combining evidence and expert opinion.

2022 EULAR recommendations for screening and prophylaxis of chronic and opportunistic infections in adults with autoimmune inflammatory rheumatic diseases.

OBJECTIVES: To develop EULAR recommendations for screening and prophylaxis of chronic and opportunistic infections in patients with autoimmune inflammatory rheumatic diseases (AIIRD). METHODS: An international Task Force (TF) (22 members/15 countries) formulated recommendations, supported by systematic literature review findings. Level of evidence and grade of recommendation were assigned for each recommendation. Level of agreement was provided anonymously by each TF member. RESULTS: Four overarching principles (OAP) and eight recommendations were developed. The OAPs highlight the need for infections to be discussed with patients and with other medical specialties, in accordance with national regulations. In addition to biologic/targeted synthetic disease-modifying antirheumatic drugs (DMARDs) for which screening for latent tuberculosis (TB) should be performed, screening could be considered also before conventional synthetic DMARDs, glucocorticoids and immunosuppressants. Interferon gamma release assay should be preferred over tuberculin skin test, where available. Hepatitis B (HBV) antiviral treatment should be guided by HBV status defined prior to starting antirheumatic drugs. All patients positive for hepatitis-C-RNA should be referred for antiviral treatment. Also, patients who are non-immune to varicella zoster virus should be informed about the availability of postexposure prophylaxis should they have contact with this pathogen. Prophylaxis against Pneumocystis jirovecii seems to be beneficial in patients treated with daily doses >15-30 mg of prednisolone or equivalent for >2-4 weeks. CONCLUSIONS: These recommendations provide guidance on the screening and prevention of chronic and opportunistic infections. Their adoption in clinical practice is recommended to standardise and optimise care to reduce the burden of opportunistic infections in people living with AIIRD.

Points to consider: EULAR-UEMS standards for the training of European rheumatologists.

BACKGROUND: Postgraduate rheumatology training programmes are already established at a national level in most European countries. However, previous work has highlighted a substantial level of heterogeneity in the organisation and, in part, content of programmes. OBJECTIVE: To define competences and standards of knowledge, skills and professional behaviours required for the training of rheumatologists. METHODS: A European Alliance of Associations for Rheumatology (EULAR) task force (TF) of 23 experts, including two members of the European Union of Medical Specialists (UEMS) section of rheumatology, was convened. The mapping phase consisted of the retrieval of key documents on specialty training in rheumatology and other related specialties across a broad set of international sources. The content of these documents was extracted and represented the foundation for the document draft that underwent several rounds of online discussion within the TF, and afterwards was also distributed to a broad group of stakeholders for collecting feedback. The list of generated competences was voted on during the TF meetings, while the level of agreement (LoA) with each statement was established by anonymous online voting. RESULTS: A total of 132 international training curricula were retrieved and extracted. In addition to the TF members, 253 stakeholders commented and voted on the competences through an online anonymous survey. The TF developed (1) an overarching framework indicating the areas that should be addressed during training, (2) 7 domains defining broad areas that rheumatology trainees should master by the end of the training programme, (3) 8 core themes defining the nuances of each domain and (4) 28 competences that trainees should acquire to cover each of the areas outlined in the overarching framework. A high LoA was achieved for all competences. CONCLUSION: These points to consider for EULAR-UEMS standards for the training of European rheumatologists are now defined. Their dissemination and use can hopefully contribute to harmonising training across European countries.

Viewpoint: Could better understanding of risk factors for comorbidities pave the way towards personalized therapy in rheumatoid arthritis?

In addition to joints, several organs can be affected in rheumatoid arthritis. Coexisting conditions with different pathomechanisms all contribute to disease activity, treatment efficacy, mortality and quality of life. The wide selection of treatment options makes it possible for rheumatologists to personalize treatment for their patients, which in present practice mainly includes the consideration of established comorbidities and contraindications. We suggest that further research can enable clinicians to take into account the individual risk of the future development of comorbidities, when making therapeutic decisions. Individual risk assessment could be mainly based on biomarkers and the better understanding of the patomechanism of different coexisting conditions, as we highlight with the examples of depression and interstitial lung disease. This biomarker-based person-centred therapy can lead not only to the treatment but ideally even the prevention of coexisting conditions, and can lead to better disease control, survival and quality of life in rheumatoid arthritis.

Comorbidities and extra-articular manifestations in difficult-to-treat rheumatoid arthritis: different sides of the same coin?

Despite the improvement in treatment for people with RA, ∼30% of patients remain symptomatic in the presence of optimized medical therapy, described as having 'difficult-to-treat' (D2T) RA. The average patient with RA has 1.6 other clinical conditions, which accumulate over time. Comorbidities are increasingly recognized as key contributors to D2T disease, and are themselves perpetuated by the D2T state. In this review, we discuss the commonest comorbidities in the context of D2T RA. We propose the need for a paradigm shift in the clinical and research agenda for comorbidities-including a need to consider and manage these prior to the development of D2T disease and not as an afterthought.

Multibiomarker disease activity score: an objective tool for monitoring rheumatoid arthritis? A systematic review and meta-analysis.

OBJECTIVES: The multibiomarker disease activity (MBDA) score is an objective tool for monitoring disease activity in RA. Here we report a systematic review and meta-analysis of the clinical value of the MBDA score in RA. METHODS: We performed a systematic literature search in five medical databases-MEDLINE (via PubMed), Cochrane Library (CENTRAL), Embase, Scopus and Web of Science-from inception to 13 October 2021. Original articles reporting on the performance of the MBDA score's correlation with conventional disease activity measures or the predictive and discriminative values of the MBDA score for radiographic progression, therapy response, remission and relapse were included. RESULTS: Our systematic search provided a total of 1190 records. After selection and citation searches, we identified 32 eligible studies. We recorded moderate correlations between MBDA score and conventional disease activity measures at baseline [correlation (COR) 0.45 (CI 0.28, 0.59), I2 = 71.0% for the 28-joint DAS with CRP (DAS28-CRP) and COR 0.55 (CI 0.19, 0.78), I2 = 0.0% for DAS28 with ESR] and at follow-up [COR 0.44 (CI 0.28, 0.57, I2 = 70.0% for DAS28-CRP) and found that the odds of radiographic progression were significantly higher for patients with a high baseline MBDA score (>44) than for patients with a low baseline MBDA score (<30) [OR 1.03 (CI 1.02-1.05), I2 = 10.0%]. CONCLUSION: The MBDA score might be used as an objective disease activity marker. In addition, it is also a reliable prognostic marker of radiographic progression.

ERN ReCONNET points to consider for treating patients living with autoimmune rheumatic diseases with antiviral therapies and anti-SARS-CoV-2 antibody products.

Recent studies have shown that people who are immunocompromised may inadvertently play a role in spurring the mutations of the virus that create new variants. This is because some immunocompromised individuals remain at risk of getting COVID-19 despite vaccination, experience more severe disease, are susceptible to being chronically infected and remain contagious for longer if they become infected and considering that immunocompromised individuals represent approximately 2% of the overall population, this aspect should be carefully considered. So far, some autoimmune rheumatic disease (ARD) patients with COVID-19 have been treated with antiviral therapies or anti-SARS-CoV-2 antibody products. However, there is no homogeneous approach to these treatment strategies. This issue was addressed within the European Reference Network (ERN) on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ReCONNET) in a discussion among experts and patient's representatives in the context of the rare and complex connective tissue diseases (rCTDs) covered by the Network. ERN ReCONNET is one of the 24 ERNs launched by the European Commission in 2017 with the aim of tackling low prevalence and rare diseases that require highly specialised treatment and promoting concentration of knowledge and resources through virtual networks involving healthcare providers (HCPs) across the European Union (EU). Considering the urgent need to provide guidance not only to the rCTDs community, but also to the whole ARDs community, a multidisciplinary Task Force, including expert clinicians and European Patient Advocacy Group (ePAG) Advocates, was created in the framework of ERN ReCONNET with the aim of developing overarching principles (OP) and points-to-consider (PtC) on a homogenous approach to treat immunocompromised patients with ARDs (with a particular focus on CTDs) affected by COVID-19 using antiviral therapies and anti-SARS-CoV-2 antibody products. The present work reports the final OP and PtC agreed by the Task Force.

COVID-19: autoimmunity, multisystemic inflammation and autoimmune rheumatic patients.

Coronavirus disease 2019 (COVID-19) is associated with autoimmunity and systemic inflammation. Patients with autoimmune rheumatic and musculoskeletal disease (RMD) may be at high risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this review, based on evidence from the literature, as well as international scientific recommendations, we review the relationships between COVID-19, autoimmunity and patients with autoimmune RMDs, as well as the basics of a multisystemic inflammatory syndrome associated with COVID-19. We discuss the repurposing of pharmaceutics used to treat RMDs, the principles for the treatment of patients with autoimmune RMDs during the pandemic and the main aspects of vaccination against SARS-CoV-2 in autoimmune RMD patients.

Synovial fibroblasts as potential drug targets in rheumatoid arthritis, where do we stand and where shall we go?

Fibroblast-like synoviocytes or synovial fibroblasts (FLS) are important cellular components of the inner layer of the joint capsule, referred to as the synovial membrane. They can be found in both layers of this synovial membrane and contribute to normal joint function by producing extracellular matrix components and lubricants. However, under inflammatory conditions like in rheumatoid arthritis (RA), they may start to proliferate, undergo phenotypical changes and become central elements in the perpetuation of inflammation through their direct and indirect destructive functions. Their importance in autoimmune joint disorders makes them attractive cellular targets, and as mesenchymal-derived cells, their inhibition may be carried out without immunosuppressive consequences. Here, we aim to give an overview of our current understanding of the target potential of these cells in RA.

EULAR points to consider for the management of difficult-to-treat rheumatoid arthritis.

OBJECTIVE: To develop evidence-based European Alliance of Associations for Rheumatology (EULAR) points to consider (PtCs) for the management of difficult-to-treat rheumatoid arthritis (D2T RA). METHODS: An EULAR Task Force was established comprising 34 individuals: 26 rheumatologists, patient partners and rheumatology experienced health professionals. Two systematic literature reviews addressed clinical questions around diagnostic challenges, and pharmacological and non-pharmacological therapeutic strategies in D2T RA. PtCs were formulated based on the identified evidence and expert opinion. Strength of recommendations (SoR, scale A-D: A typically consistent level 1 studies and D level 5 evidence or inconsistent studies) and level of agreement (LoA, scale 0-10: 0 completely disagree and 10 completely agree) of the PtCs were determined by the Task Force members. RESULTS: Two overarching principles and 11 PtCs were defined concerning diagnostic confirmation of RA, evaluation of inflammatory disease activity, pharmacological and non-pharmacological interventions, treatment adherence, functional disability, pain, fatigue, goal setting and self-efficacy and the impact of comorbidities. The SoR varied from level C to level D. The mean LoA with the overarching principles and PtCs was generally high (8.4-9.6). CONCLUSIONS: These PtCs for D2T RA can serve as a clinical roadmap to support healthcare professionals and patients to deliver holistic management and more personalised pharmacological and non-pharmacological therapeutic strategies. High-quality evidence was scarce. A research agenda was created to guide future research.

Mechanisms underlying DMARD inefficacy in difficult-to-treat rheumatoid arthritis: a narrative review with systematic literature search.

Management of RA patients has significantly improved over the past decades. However, a substantial proportion of patients is difficult-to-treat (D2T), remaining symptomatic after failing biological and/or targeted synthetic DMARDs. Multiple factors can contribute to D2T RA, including treatment non-adherence, comorbidities and co-existing mimicking diseases (e.g. fibromyalgia). Additionally, currently available biological and/or targeted synthetic DMARDs may be truly ineffective ('true' refractory RA) and/or lead to unacceptable side effects. In this narrative review based on a systematic literature search, an overview of underlying (immune) mechanisms is presented. Potential scenarios are discussed including the influence of different levels of gene expression and clinical characteristics. Although the exact underlying mechanisms remain largely unknown, the heterogeneity between individual patients supports the assumption that D2T RA is a syndrome involving different pathogenic mechanisms.

Rare clinical manifestations in systemic lupus erythematosus: a review on frequency and clinical presentation.

OBJECTIVES: The purpose of this study was to review the frequency and clinical presentation of the rarest clinical manifestations of systemic lupus erythematosus (SLE). METHODS: A list of 6 rare SLE manifestations were defined: gastrointestinal, liver, pulmonary, cardiac, ocular and neurological manifestations. Each topic was assigned to a pair of authors to perform a literature search and article review. RESULTS: In total, 149 articles were included in the literature review: 37 for gastrointestinal manifestations, 6 for liver manifestations, 27 for pulmonary manifestations, 50 for cardiac manifestations, 16 for ocular manifestations, 13 for neurological manifestations. Gastrointestinal disorders included several clinical presentations with variable frequency (from 0.5% to 10.7% of the cases); liver involvement included lupus-related hepatitis (9.3%) and autoimmune hepatitis (2.3%). The rarest pulmonary manifestations identified were shrinking lung syndrome, described in 1.5% of patients, while interstitial lung disease and lupus pneumonia were reported in 4% and 3% of patients respectively. Myocarditis and pulmonary hypertension were also rarely described in SLE patients although ranging from 0.4-16% and 1-14% respectively, depending on the methodology used for its identification. Ocular manifestations in SLE included some rare manifestations (reported in less than 5% of patients) and lupus retinopathy that is described in 1.2-28.8% of patients depending on methods of ascertainment. Aseptic meningitis and chorea were also confirmed as very rare manifestations being reported in less than 1% and in 0.3-2.4% of cases respectively. CONCLUSIONS: The results of this literature review provide the basis for a better understanding of some less-known manifestations of SLE and for stressing the need for a higher awareness in diagnostic and therapeutic protocols regarding these rare disease aspects.

Off-label use of mycophenolate mofetil in the treatment of rare and complex rheumatic connective tissue diseases.

OBJECTIVES: We aimed to investigate the clinical off-label use of mycophenolate mofetil (MMF), including its safety and efficacy in patients with rare and complex rheumatic connective tissue diseases (rCTDs). METHODS: A survey was distributed across experts from ERN-ReCONNET reference centres in order to assess the experience with MMF off-label use. Patient-level data of patients with rCTDs under treatment with MMF was also collected for analysis of safety and efficacy. RESULTS: Twelve experts from eleven centres distributed throughout Europe (7 countries) answered the survey. The experience was concordant in that, despite of its off-label use, experts reported opting frequently for this therapeutic alternative with robust confidence on its efficacy and safety. The analysis of 108 patients with rCTDs under MMF revealed a good safety profile, as well as good clinical outcomes, especially for systemic lupus erythematosus and idiopathic inflammatory myopathies. The presence of interstitial lung disease was, as expected, associated with a worse clinical outcome despite use of MMF. CONCLUSIONS: MMF is widely used in reference centres for rCTDs. Its safety profile and efficacy seem to be recognised by experts and demonstrated with patient-level analysis. While selected rCTDs will likely remain an off-label indication for MMF, robust data seem to support this therapy as an appropriate alternative for safely and effectively treating many manifestations of rCTDs.

The added value of a European Reference Network on rare and complex connective tissue and musculoskeletal diseases: insights after the first 5 years of the ERN ReCONNET.

In order to address the main challenges related to the rare diseases (RDs) the European Commission launched the European Reference Networks (ERNs), virtual networks involving healthcare providers (HCPs) across Europe. The mission of the ERNs is to tackle low prevalence and RDs that require highly specialised treatment and a concentration of knowledge and resources. In fact, ERNs offer the potential to give patients and healthcare professionals across the EU access to the best expertise and timely exchange of lifesaving knowledge, trying to make the knowledge travelling more than patients. For this reason, ERNs were established as concrete European infrastructures, and this is particularly crucial in the framework of rare and complex diseases in which no country alone has the whole knowledge and capacity to treat all types of patients.It has been five years since their kick-off launch in Vilnius in 2017. The 24 ERNs have been intensively working on different transversal areas, including patient management, education, clinical practice guidelines, patients' care pathways and many other fundamental topics. The present work is therefore aimed not only at reporting a summary of the main activities and milestones reached so far, but also at celebrating the first 5 years of the ERN on Rare and Complex Connective Tissue and Musculo-skeletal Diseases (ReCONNET), in which the members of the network built together one of the 24 infrastructures that are hopefully going to change the scenario of rare diseases across the EU.

Janus Kinase Inhibitors Improve Disease Activity and Patient-Reported Outcomes in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis of 24,135 Patients.

Pain, fatigue, and physical activity are major determinants of life quality in rheumatoid arthritis (RA). Janus kinase (JAK) inhibitors have emerged as effective medications in RA and have been reported to exert direct analgesic effect in addition to reducing joint inflammation. This analysis aims to give an extensive summary of JAK inhibitors especially focusing on pain and patient reported outcomes (PRO). MEDLINE, CENTRAL, Embase, Scopus, and Web of Science databases were searched on the 26 October 2020, and 50 randomized controlled trials including 24,135 adult patients with active RA met the inclusion criteria. JAK inhibitors yielded significantly better results in all 36 outcomes compared to placebo. JAK monotherapy proved to be more effective than methotrexate in 9 out of 11 efficacy outcomes. In comparison to biological disease-modifying antirheumatic drugs, JAK inhibitors show statistical superiority in 13 of the 19 efficacy outcomes. Analgesic effect determined using the visual analogue scale and American College of Rheumatology (ACR) 20/50/70 response rates was significantly greater in the JAK group in all comparisons, and no significant difference regarding safety could be explored. This meta-analysis gives a comprehensive overview of JAK inhibitors and provides evidence for their superiority in improving PROs and disease activity indices in RA.

Preclinical models of arthritis for studying immunotherapy and immune tolerance.

Increasingly earlier identification of individuals at high risk of rheumatoid arthritis (RA) (eg, with autoantibodies and mild symptoms) improves the feasibility of preventing or curing disease. The use of antigen-specific immunotherapies to reinstate immunological self-tolerance represent a highly attractive strategy due to their potential to induce disease resolution, in contrast to existing approaches that require long-term treatment of underlying symptoms.Preclinical animal models have been used to understand disease mechanisms and to evaluate novel immunotherapeutic approaches. However, models are required to understand critical processes supporting disease development such as the breach of self-tolerance that triggers autoimmunity and the progression from asymptomatic autoimmunity to joint pain and bone loss. These models would also be useful in evaluating the response to treatment in the pre-RA period.This review proposes that focusing on immune processes contributing to initial disease induction rather than end-stage pathological consequences is essential to allow development and evaluation of novel immunotherapies for early intervention. We will describe and critique existing models in arthritis and the broader field of autoimmunity that may fulfil these criteria. We will also identify key gaps in our ability to study these processes in animal models, to highlight where further research should be targeted.

EULAR definition of difficult-to-treat rheumatoid arthritis.

BACKGROUND: Despite treatment according to the current management recommendations, a significant proportion of patients with rheumatoid arthritis (RA) remain symptomatic. These patients can be considered to have 'difficult-to-treat RA'. However, uniform terminology and an appropriate definition are lacking. OBJECTIVE: The Task Force in charge of the "Development of EULAR recommendations for the comprehensive management of difficult-to-treat rheumatoid arthritis" aims to create recommendations for this underserved patient group. Herein, we present the definition of difficult-to-treat RA, as the first step. METHODS: The Steering Committee drafted a definition with suggested terminology based on an international survey among rheumatologists. This was discussed and amended by the Task Force, including rheumatologists, nurses, health professionals and patients, at a face-to-face meeting until sufficient agreement was reached (assessed through voting). RESULTS: The following three criteria were agreed by all Task Force members as mandatory elements of the definition of difficult-to-treat RA: (1) Treatment according to European League Against Rheumatism (EULAR) recommendation and failure of ≥2 biological disease-modifying antirheumatic drugs (DMARDs)/targeted synthetic DMARDs (with different mechanisms of action) after failing conventional synthetic DMARD therapy (unless contraindicated); (2) presence of at least one of the following: at least moderate disease activity; signs and/or symptoms suggestive of active disease; inability to taper glucocorticoid treatment; rapid radiographic progression; RA symptoms that are causing a reduction in quality of life; and (3) the management of signs and/or symptoms is perceived as problematic by the rheumatologist and/or the patient. CONCLUSIONS: The proposed EULAR definition for difficult-to-treat RA can be used in clinical practice, clinical trials and can form a basis for future research.

Ipsilateral and Simultaneous Comparison of Responses from Acceleromyography- and Electromyography-based Neuromuscular Monitors.

BACKGROUND: The paucity of easy-to-use, reliable objective neuromuscular monitors is an obstacle to universal adoption of routine neuromuscular monitoring. Electromyography (EMG) has been proposed as the optimal neuromuscular monitoring technology since it addresses several acceleromyography limitations. This clinical study compared simultaneous neuromuscular responses recorded from induction of neuromuscular block until recovery using the acceleromyography-based TOF-Watch SX and EMG-based TetraGraph. METHODS: Fifty consenting patients participated. The acceleromyography and EMG devices analyzed simultaneous contractions (acceleromyography) and muscle action potentials (EMG) from the adductor pollicis muscle by synchronization via fiber optic cable link. Bland-Altman analysis described the agreement between devices during distinct phases of neuromuscular block. The primary endpoint was agreement of acceleromyography- and EMG-derived normalized train-of-four ratios greater than or equal to 80%. Secondary endpoints were agreement in the recovery train-of-four ratio range less than 80% and agreement of baseline train-of-four ratios between the devices. RESULTS: Acceleromyography showed normalized train-of-four ratio greater than or equal to 80% earlier than EMG. When acceleromyography showed train-of-four ratio greater than or equal to 80% (n = 2,929), the bias was 1.3 toward acceleromyography (limits of agreement, -14.0 to 16.6). When EMG showed train-of-four ratio greater than or equal to 80% (n = 2,284), the bias was -0.5 toward EMG (-14.7 to 13.6). In the acceleromyography range train-of-four ratio less than 80% (n = 2,802), the bias was 2.1 (-16.1 to 20.2), and in the EMG range train-of-four ratio less than 80% (n = 3,447), it was 2.6 (-14.4 to 19.6). Baseline train-of-four ratios were higher and more variable with acceleromyography than with EMG. CONCLUSIONS: Bias was lower than in previous studies. Limits of agreement were wider than expected because acceleromyography readings varied more than EMG both at baseline and during recovery. The EMG-based monitor had higher precision and greater repeatability than acceleromyography. This difference between monitors was even greater when EMG data were compared to raw (nonnormalized) acceleromyography measurements. The EMG monitor is a better indicator of adequate recovery from neuromuscular block and readiness for safe tracheal extubation than the acceleromyography monitor.

Impact of Medium-Sized Extracellular Vesicles on the Transduction Efficiency of Adeno-Associated Viruses in Neuronal and Primary Astrocyte Cell Cultures.

(1) Adeno-associated viruses (AAV) are safe and efficient gene therapy vectors with promising results in the treatment of several diseases. Extracellular vesicles (EV) are phospholipid bilayer-surrounded structures carrying several types of lipids, proteins, and nucleic acids with the ability to cross biological barriers. EV-associated AAVs might serve as new and efficient gene therapy vectors considering that they carry the benefits of both AAVs and EVs. (2) We tested vesicle-associated AAVs and vesicles mixed with AAVs on two major cell types of the central nervous system: a neural cell line (N2A) and primary astrocyte cells. (3) In contrast to previously published in vivo observations, the extracellular vesicle packaging did not improve but, in the case of primary astrocyte cells, even inhibited the infection capacity of the AAV particles. The observed effect was not due to the inhibitory effects of the vesicles themselves, since mixing the AAVs with extracellular vesicles did not change the effectiveness. (4) Our results suggest that improvement of the in vivo efficacy of the EV-associated AAV particles is not due to the enhanced interaction between the AAV and the target cells, but most likely to the improved delivery of the AAVs through tissue barriers and to the shielding of AAVs from neutralizing antibodies.