Common to all inflammatory arthritides, namely rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis, and juvenile idiopathic arthritis, is a potential for reduced mobility that manifests through joint pain, swelling, stiffness, and ultimately joint damage. Across these conditions, consensus has been reached on the need to capture outcomes related to mobility, such as functional capacity and physical activity, as core domains in randomised controlled trials. Existing endpoints within these core domains rely wholly on self-reported questionnaires that capture patients' perceptions of their symptoms and activities. These questionnaires are subjective, inherently vulnerable to recall bias, and do not capture the granularity of fluctuations over time. Several early adopters have integrated sensor-based digital health technology (DHT)-derived endpoints to measure physical function and activity in randomised controlled trials for conditions including Parkinson's disease, Duchenne's muscular dystrophy, chronic obstructive pulmonary disease, and heart failure. Despite these applications, there have been no sensor-based DHT-derived endpoints in clinical trials recruiting patients with inflammatory arthritis. Borrowing from case studies across medicine, we outline the opportunities and challenges in developing novel sensor-based DHT-derived endpoints that capture the symptoms and disease manifestations most relevant to patients with inflammatory arthritis.

Anti-synthetase syndrome (ASS) is a chronic autoimmune condition, with interstitial lung disease (ILD) being a key feature. This systematic literature review (SLR; CRD42023416414) aimed to summarize treatments and outcomes of ILD associated with ASS (ASS-ILD).

To assess current treatment in macrophage activation syndrome (MAS) worldwide and to highlight any areas of major heterogeneity of practice.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by high heterogeneity of clinical manifestations and an uncertain prognosis. Although the mortality rate due to SLE has decreased significantly in recent decades, there is still a need to find good tools to measure disease activity for early detection of exacerbations and treatment planning. Over the decades, more than a dozen disease activity scales/indicators have been developed, with the SLE Disease Activity Index (SLEDAI) being the most popular. More recently, the new SLE Disease Activity Score (SLE-DAS) has been introduced. This paper compares the two methods of assessing SLE activity, and presents the relevance of these scales in pregnant SLE patients and their use in formulating definitions of remission and low disease activity. The results show that the SLEDAI and the SLE-DAS are of comparable value in assessing SLE activity and complement each other.

Residual pain is a major unmet medical need observed in patients suffering from rheumatoid arthritis (RA), which decreases their quality of life, even after achieving remission or low disease activity. The article has two aims: 1) to present mechanisms involved in the pathophysiology of residual pain, both inflammatory and non-inflammatory, i.e. neuropathic and nociplastic pain, as well as secondary pain syndromes, i.e. osteoarthritis and fibromyalgia, which can contribute to residual pain; 2) to show the limitations of current disease activity measures recommended by European Alliance of Associations for Rheumatology (EULAR) and American College of Rheumatology (ACR), which raise the need for a separate assessment of pain, and examples of methods that could be used by medical professionals to assess the pain and make a differential diagnosis. In conclusion, establishing a valid method to assess pain is essential to identify the pathomechanism of residual pain and to create treatments tailored specifically to individual RA patients.

Hyperuricemia, characterized by elevated levels of uric acid in the body, is associated with several health risks, including gout, urolithiasis and cardiovascular disease. Although treatment options are available, they can lead to hypersensitivity reactions, particularly with allopurinol therapy. This paper provides a comprehensive review of the consequences of hyperuricemia, the need for treatment and the potential adverse effects of allopurinol, illustrated by a case study. The study highlights the importance of careful consideration before initiating therapy, particularly in patients with comorbidities and concomitant medication. It emphasizes the need for vigilant monitoring and individualized treatment approaches to reduce adverse effects. In addition, genetic factors, particularly HLA-B*5801, play an important role in determining susceptibility to allopurinol hypersensitivity reactions. This paper highlights the importance of informed decision making in the management of hyperuricemia to optimize patient outcomes while minimizing the risks associated with treatment.

Magnetic resonance imaging (MRI) of the musculoskeletal system is an examination increasingly performed for suspected juvenile idiopathic arthritis, chronic nonbacterial osteomyelitis and juvenile idiopathic inflammatory myopathies, as well as other rheumatic diseases of developmental age. T1-, T2- and PD-weighted with or without fat suppression or short tau inversion recovery/turbo inversion recovery magnitude (STIR/TIRM) sequences and post-contrast sequences are evaluated to diagnose pathological changes in the synovial membrane, subchondral bone marrow and surrounding soft tissues. Magnetic resonance imaging allows detection of synovitis, tenosynovitis, bursitis, and enthesitis as well as bone marrow edema and soft tissue edema. Several pediatric-specific MRI scoring systems have been developed and validated to standardize and facilitate the assessment of the extent of the inflammatory process and disease activity in MRI. Early detection of inflammatory changes allows the inclusion of comprehensive pharmacotherapy giving the possibility of permanent remission and objective measurement of the effectiveness of treatment.

Fundamental advances are occurring across immune-mediated inflammatory diseases. Recent therapeutic developments include strategies to prevent rheumatoid arthritis in high-risk individuals, using baseline cellular immunophenotypes to predict response to biologics in psoriatic arthritis, and using biologics in a top-down approach for Crohn's disease. However, meaningful progress has not occurred in the management of patients with spondyloarthropathy complicating inflammatory bowel disease (IBD). Currently, the pathophysiology of IBD-related spondyloarthropathy is poorly understood; moreover, there are no accepted or disease-specific screening tools, diagnostic criteria, or licenced treatments. Current approaches to clinical care from rheumatologists and gastroenterologists largely involve the extrapolation of spondyloarthropathy and IBD clinical guidelines, respectively, despite increasing recognition of IBD-related spondyloarthropathy being its own entity, with a unique phenotype. There is an obvious contrast between spondyloarthropathy complicating IBD and the management of arthropathy complicating psoriasis, a disease area where defined diagnostic criteria and dedicated clinical trials allow clear management guidelines. We argue that the time has come for a parallel approach and dedicated focus on IBD-related spondyloarthropathy.

Integrins are key regulators of cell-matrix interactions during joint development and joint tissue homeostasis, as well as in the development of osteoarthritis (OA). The signalling cascades initiated by the interactions of integrins with a complex network of extracellular matrix (ECM) components and intracellular adaptor proteins orchestrate cellular responses necessary for maintaining joint tissue integrity. Dysregulated integrin signalling, triggered by matrix degradation products such as matrikines, disrupts this delicate balance, tipping the scales towards an environment conducive to OA pathogenesis. The interplay between integrin signalling and growth factor pathways further underscores the multifaceted nature of OA. Moreover, emerging insights into the role of endocytic trafficking in regulating integrin signalling add a new layer of complexity to the understanding of OA development. To harness the therapeutic potential of targeting integrins for mitigation of OA, comprehensive understanding of their molecular mechanisms across joint tissues is imperative. Ultimately, deciphering the complexities of integrin signalling will advance the ability to treat OA and alleviate its global burden.

The pathogenesis of gout involves a series of steps beginning with hyperuricaemia, followed by the deposition of monosodium urate crystal in articular structures and culminating in an innate immune response, mediated by the NLRP3 inflammasome, to the deposited crystals. Large genome-wide association studies (GWAS) of serum urate levels initially identified the genetic variants with the strongest effects, mapping mainly to genes that encode urate transporters in the kidney and gut. Other GWAS highlighted the importance of uncommon genetic variants. More recently, genetic and epigenetic genome-wide studies have revealed new pathways in the inflammatory process of gout, including genetic associations with epigenomic modifiers. Epigenome-wide association studies are also implicating epigenomic remodelling in gout, which perhaps regulates the responsiveness of the innate immune system to monosodium urate crystals. Notably, genes implicated in gout GWAS do not include those encoding components of the NLRP3 inflammasome itself, but instead include genes encoding molecules involved in its regulation. Knowledge of the molecular mechanisms underlying gout has advanced through the translation of genetic associations into specific molecular mechanisms. Notable examples include ABCG2, HNF4A, PDZK1, MAF and IL37. Current genetic studies are dominated by participants of European ancestry; however, studies focusing on other population groups are discovering informative population-specific variants associated with gout.

Sjögren syndrome or Sjögren disease is a chronic form of autoimmune epithelitis characterized by lymphocytic infiltration of the exocrine glands, particularly the salivary and lacrimal glands, leading to progressive glandular dysfunction and subsequent xerostomia and xerophthalmia. Other common manifestations include pain and fatigue, various systemic manifestations and non-Hodgkin's lymphoma. Sjögren syndrome is therefore a complex and disabling disease associated with a reduced quality of life and with considerable long-term damage. Most of the available treatments are merely symptomatic with limited efficacy in both preventing glandular damage and suppressing systemic disease activity. In the past 10 years, great progress has been made in understanding the pathophysiology of Sjögren syndrome, opening new avenues towards a more targeted and individualized therapeutic approach to the disease. Indeed, several randomized controlled trials have just been completed or are poised to commence evaluating the effectiveness of novel drugs targeting both innate and adaptive immune pathways, including pro-inflammatory cytokines, the type I interferon system, B cell activation, B cell and T cell co-stimulation pathway, and ectopic germinal centre formation. Novel clinical trials are also ongoing exploring various targeted approaches (that is, IgG recycling inhibition, nuclease therapy and CAR-T cell therapy) for Sjögren syndrome.

The first inhabitants of Australia and the traditional owners of Australian lands are the Aboriginal and Torres Strait Islander peoples. Aboriginal and Torres Strait Islander peoples are two to four times more likely to have systemic lupus erythematosus (SLE) than the general Australian population. Phenotypically, SLE appears distinctive in Aboriginal and Torres Strait Islander peoples and its severity is substantially increased, with mortality rates up to six times higher than in the general Australian population with SLE. In particular, Aboriginal and Torres Strait Islander peoples with SLE have increased prevalence of lupus nephritis and increased rates of progression to end-stage kidney disease. The reasons for the increased prevalence and severity of SLE in this population are unclear, but socioeconomic, environmental, and biological factors are all likely to be implicated, although there are no published studies investigating these factors in Aboriginal and Torres Strait Islander peoples with SLE specifically, indicating an important knowledge gap. In this Review, we summarise the data on the incidence, prevalence, and clinical and biological findings relating to SLE in Aboriginal and Torres Strait Islander peoples and explore potential factors contributing to its increased prevalence and severity in this population. Importantly, we identify health disparities and deficiencies in health-care provision that limit optimal care and outcomes for many Aboriginal and Torres Strait Islander peoples with SLE and highlight potentially addressable goals to improve outcomes.

Familial Mediterranean Fever (FMF) is the most common monogenic autoinflammatory disease characterized by recurrent fever and serosal inflammation. Although colchicine is the primary treatment, around 10% of FMF patients do not respond to it, necessitating alternative therapies. Biologic treatments, such as IL-1β, TNF-α and IL-6 inhibitors, have been considered. However, the accessibility and cost of IL-1β inhibitors may limit their use in certain regions. Tocilizumab (TCZ), an IL-6 receptor inhibitor, offers an alternative, but its efficacy in FMF is not well-documented.

SLE presents significant challenges for patients and health-care professionals (HCPs), both across Europe and worldwide. Improving health-care outcomes for patients with SLE requires a comprehensive understanding of patient disease pathways. In particular, the geographical distance between SLE patients and specialized care centres, combined with the scarcity of rheumatologists, exacerbates delays in diagnosis and management. Also, the initial SLE symptoms can often be non-specific, and providing guidelines for primary HCPs and other non-specialists is extremely important. Improvement in access to treatment is also important, with several recently approved therapies for SLE not being available in several European countries and many low- and middle-income countries (LMICs). Furthermore, in the LMICs in which these treatments are available, they are not always covered by the health-care system, making their access almost impossible for those of lower socio-economic status. A number of provisions are already in place within the European Union, to improve access to care for patients with rare and complex diseases, including those with SLE. In particular, European Reference Networks (ERNs), such the ERN for Autoimmune Diseases ReCONNET, are virtual networks involving HCPs across Europe with the aim of improving the care of patients with rare and complex diseases that require highly specialized treatment and a concentration of knowledge and resources. In addition, lupus patient organizations such as Lupus Europe play a crucial role in raising awareness of SLE and advocating for improved access to care. Together, we can work towards a future where all people living with lupus receive the comprehensive and timely care they deserve.

Kawasaki disease, a systemic vasculitis that affects young children and can result in coronary artery aneurysms, is the leading cause of acquired heart disease among children. A hallmark of Kawasaki disease is increased blood platelet counts and platelet activation, which is associated with an increased risk of developing resistance to intravenous immunoglobulin and coronary artery aneurysms. Platelets and their releasate, including granules, microparticles, microRNAs and transcription factors, can influence innate immunity, enhance inflammation and contribute to vascular remodelling. Growing evidence indicates that platelets also interact with immune and non-immune cells to regulate inflammation. Platelets boost NLRP3 inflammasome activation and IL-1β production by human immune cells by releasing soluble mediators. Activated platelets form aggregates with leukocytes, such as monocytes and neutrophils, enhancing numerous functions of these cells and promoting thrombosis and inflammation. Leukocyte-platelet aggregates are increased in children with Kawasaki disease during the acute phase of the disease and can be used as biomarkers for disease severity. Here we review the role of platelets in Kawasaki disease and discuss progress in understanding the immune-effector role of platelets in amplifying inflammation related to Kawasaki disease vasculitis and therapeutic strategies targeting platelets or platelet-derived molecules.

Rheumatic and musculoskeletal diseases often affect individuals of childbearing age. The incidence and prevalence of rheumatic and musculoskeletal diseases is rising. More pregnancies in patients with rheumatic and musculoskeletal diseases are anticipated and some rheumatic and musculoskeletal diseases are associated with pregnancy complications (eg, miscarriages, fetal deaths, preterm births, and hypertensive disorders in pregnancy). Despite the need to understand the use of drugs to treat rheumatic and musculoskeletal diseases in pregnancy, clinical trials in pregnancy are rare, therapeutics in pregnancy are understudied, and pregnant individuals are routinely excluded as premarketing trial participants. Data on the effectiveness and safety of disease-modifying antirheumatic drugs are most often based on post-marketing observational data. Observational studies assessing the bidirectional relationship between rheumatic and musculoskeletal diseases and pregnancy, as well as interventional studies of treatments during pregnancy, are scarce. Historical reluctance to perform studies in what was deemed an at-risk group persists in pharmaceutical companies, regulatory bodies, and ethics boards. Additionally, patients must be engaged partners, which requires trust that the research respects the needs and interests of the patient and complies with the rules intended to protect the pregnant person and the fetus from harm. In this Series paper, we share challenges we have encountered in conducting prospective cohort studies and interventional trials of postmarketing approved medications, assessing pregnancy specific outcomes in pregnant women with rheumatic and musculoskeletal diseases in the EU, the UK, and the USA. We discuss the changing landscape around trials in pregnancy and present possible solutions to our challenges.

Maternal autoimmune rheumatic diseases can influence the outcomes of children through several life stages. During pregnancy, maternal inflammation and autoantibodies can hinder fetal development and lead to growth restriction, preterm birth, and low birth weight; prematurity, especially at extreme gestational ages, can in turn impair future child health. Treatment with compatible immunomodulatory drugs and preventive medications aims to keep maternal disease under control and minimise the risk of adverse pregnancy outcomes. However, concerns have been raised about the effects of immunomodulatory drugs on neonatal conditions (ie, the risk of serious infections, inadequate responses to vaccinations, and organ toxicity) and long-term outcomes (metabolic and cardiovascular problems and neurodevelopmental disorders). Among the unmet needs of parents with autoimmune rheumatic diseases, there is the estimation of risk for the children to develop autoimmune disorders and the need for reassurance about parenting capacity while living with a chronic condition. This Series paper provides a comprehensive overview of the literature and guidance on discussing these topics with patients.

Active inflammatory arthritis in pregnancy is associated with an increased risk of adverse pregnancy outcomes. Treatment of active inflammation and maintenance of low disease activity with medication reduces these risks. Therapeutic decisions on disease-modifying antirheumatic drugs (DMARDs) in pregnancy are complicated by safety concerns, which have led to inappropriate withdrawal of treatment and consequential harm to mother and fetus. Studies of inflammatory arthritis in pregnancy have consistently shown minimal safety concerns with the use of biological DMARDs and an increased risk of disease flare with discontinuation of biological DMARDs. It is our opinion that during pregnancy, the benefits of disease control with biological DMARDs, when required in addition to conventional synthetic DMARDs, outweigh the risks. In this Series paper, we review the reasons for reconsideration of equipoise and propose an agenda for future research to optimise the use of biological DMARDs in inflammatory arthritis during pregnancy.

Joint kinematic instability, arising from congenital or acquired musculoskeletal pathoanatomy or from imbalances in anabolism and catabolism induced by pathophysiological factors, leads to deterioration of the composition, structure and function of cartilage and, ultimately, progression to osteoarthritis (OA). Alongside articular cartilage degeneration, synovial fluid lubricity decreases in OA owing to a reduction in the concentration and molecular weight of hyaluronic acid and surface-active mucinous glycoproteins that form a lubricating film over the articulating joint surfaces. Minimizing friction between articulating joint surfaces by lubrication is fundamental for decreasing hyaline cartilage wear and for maintaining the function of synovial joints. Augmentation with highly viscous supplements (that is, viscosupplementation) offers one approach to re-establishing the rheological and tribological properties of synovial fluid in OA. However, this approach has varied clinical outcomes owing to limited intra-articular residence time and ineffective mechanisms of chondroprotection. This Review discusses normal hyaline cartilage function and lubrication and examines the advantages and disadvantages of various strategies for restoring normal joint lubrication. These strategies include contemporary viscosupplements that contain antioxidants, anti-inflammatory drugs or platelet-rich plasma and new synthetic synovial fluid additives and cartilage matrix enhancers. Advanced biomimetic tribosupplements offer promise for mitigating cartilage wear, restoring joint function and, ultimately, improving patient care.