Treatment of Axial Spondyloarthritis: What Does the Future Hold?

Cardiovascular disease in spondyloarthritis: a narrative review of risk factors and the effect of treatments

PURPOSE OF REVIEW

This review summarizes the recent evidence available regarding the epidemiology of cardiovascular disease in spondyloarthritis (SpA), including the effect of disease modifying drugs on cardiovascular risk.

RECENT FINDINGS

People with SpA suffer from an increased risk of cardiovascular disease compared to the general population. This elevated risk is explained by the high prevalence of traditional cardiovascular risk factors and inflammation from disease activity leading to endothelial dysfunction and accelerated atherosclerosis. Consequently, the American College of Cardiology/American Heart Association and the European League Against Rheumatism recommend enhanced cardiovascular risk screening in SpA patients. There is evidence from observational studies that methotrexate and tumor necrosis factor inhibitors reduce the risk of cardiovascular events in SpA. Unlike what is observed in the general population, the use of nonsteroidal anti-inflammatory drugs does not appear to increase cardiovascular disease risk in SpA.

SUMMARY

Cardiovascular diseases are increasingly recognized in patients suffering from SpA, especially axial SpA and psoriatic arthritis. Cardiovascular diseases can cause significant morbidity, mortality, and add to the overall disease burden. Disease modifying drugs may mitigate some of the cardiovascular risk; however, a multidisciplinary team is needed to monitor patients and improve cardiovascular health status.

PKM2 promotes proinflammatory macrophage activation in ankylosing spondylitis

Macrophages play a critical role in ankylosing spondylitis by promoting autoimmune tissue inflammation through various effector functions. The inflammatory potential of macrophages is highly influenced by their metabolic environment. Here, we demonstrate that glycolysis is linked to the proinflammatory activation of human blood monocyte-derived macrophages in ankylosing spondylitis. Specifically, ankylosing spondylitis macrophages produced excessive inflammation, including TNFα, IL1β, and IL23, and displayed an overactive status by exhibiting stronger costimulatory signals, such as CD80, CD86, and HLA-DR. Moreover, we found that patient-derived monocyte-derived M1-type macrophages (M1 macrophages) exhibited intensified glycolysis, as evidenced by a higher extracellular acidification rate. Upregulation of PKM2 and GLUT1 was observed in ankylosing spondylitis-derived monocytes and monocyte-derived macrophages, especially in M1 macrophages, indicating glucose metabolic alteration in ankylosing spondylitis macrophages. To investigate the impact of glycolysis on macrophage inflammatory ability, we treated ankylosing spondylitis M1 macrophages with 2 inhibitors: 2-deoxy-D-glucose, a glycolysis inhibitor, and shikonin, a PKM2 inhibitor. Both inhibitors reduced proinflammatory function and reversed the overactive status of ankylosing spondylitis macrophages, suggesting their potential utility in treating the disease. These data place PKM2 at the crosstalk between glucose metabolic changes and the activation of inflammatory macrophages in patients with ankylosing spondylitis.

Cardiovascular comorbidities in spondyloarthritis

In recent years, many researchers have focused on the development of comorbidities associated with axial spondyloarthritis. Hypertension, smoking, dyslipidemia, diabetes mellitus, obesity, and the presence of inflammation, which is a well-known risk factor, increase cardiovascular comorbidities. Previous studies reported that HLA-B27 might be a genetic risk factor for various cardiac conditions. In the treatment and follow-up, raising the awareness of cardiovascular risk and guiding clinical practice and future research in rheumatic and musculoskeletal diseases should be aimed. There is consensus that cardiovascular risks should be evaluated periodically in these patients, particularly during the course of treatment. A decision regarding the selection and follow-up protocols of the drugs should be made considering all the risks and benefits in spondyloarthropathies. In this review, we discussed the recommendations and practices for the management of cardiovascular comorbidities in axial spondyloarthritis. Key Points • The risk of cardiovascular morbidity and mortality is increased in axial spondyloarthritis. • Higher disease activity increases cardiovascular risk factors. • Axial spondyloarthritis patients should be carefully monitored for signs of cardiovascular events as this is necessary to ensure that patients are treated appropriately and awareness should be raised in all patients. • Reducing the activity of the underlying disease with an appropriate and early treatment will also reduce the risk of cardiovascular events.

Functional Assessment of Chronic Illness Therapy-Fatigue is a reliable and valid measure in patients with active ankylosing spondylitis

Background

The Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale has demonstrated good internal consistency and responsiveness to changes in clinical status among patients with ankylosing spondylitis (AS). We aimed to further evaluate the psychometric properties of the FACIT-F scale in adult patients with AS.

Methods

Measurement properties of the FACIT-F scale were evaluated using data from tofacitinib phase 2/3 (NCT01786668/NCT03502616) studies in adult patients with active AS.

Results

Second-order confirmatory factor modeling supported the measurement structure of the FACIT-F scale (Bentler’s comparative fit index ≥ 0.91), and FACIT-F demonstrated excellent internal consistency (Cronbach’s coefficient α ≥ 0.88) and test–retest reliability (Intraclass Correlation Coefficient ≥ 0.75). Correlation coefficients between FACIT-F and other patient-reported outcomes generally exceeded 0.40, supporting convergent validity. Meaningful within-patient change was estimated as 3.1–6.3 for FACIT-F total score, and 1.4–2.8 and 1.7–3.6 for FACIT-F Experience and Impact domain scores, respectively. Large (effect size ≥ 1.17 standard deviation units), statistically significant differences in FACIT-F domain/total scores between ‘no disease activity’ (Patient Global Assessment of Disease Activity [PtGA] = 0) and ‘very active disease’ (PtGA = 10) patient groups supported known-groups validity. Ability to detect change was evidenced by an approximately linear relationship between changes in FACIT-F and PtGA scores.

Conclusions

FACIT-F is a reliable and valid measure for evaluating fatigue in adult patients with active AS.

Trial registration: ClinicalTrials.gov; NCT01786668 (registered 6 February 2013, https://clinicaltrials.gov/ct2/show/NCT01786668) and NCT03502616 (registered 11 April 2018, https://clinicaltrials.gov/ct2/show/NCT03502616).

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00508-0.

Ankylosing spondylitis (AS) is a disease that causes pain and stiffness in the spine. AS is a chronic disease. Most people with AS experience fatigue (a feeling of being very tired or exhausted). People with more severe AS tend to have more fatigue and a lower level of well-being. Because of this, fatigue is an important symptom to measure in studies of AS. The Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) is a questionnaire that measures fatigue. It has 13 questions that assess level of fatigue over a week’s time. The FACIT-F has not been studied in depth in people with AS. Therefore, we analyzed results from two clinical trials. We found that FACIT-F was a reliable and valid way to measure fatigue in adults with AS. This makes it a suitable tool to use in AS clinical trials.

Wearables for Measuring the Physical Activity and Sedentary Behavior of Patients With Axial Spondyloarthritis: Systematic Review

Background

Axial spondyloarthritis (axSpA) is an inflammatory rheumatic disease associated with chronic back pain and restricted mobility and physical function. Increasing physical activity is a viable strategy for improving the health and quality of life of patients with axSpA. Thus, quantifying physical activity and sedentary behavior in this population is relevant to clinical outcomes and disease management. However, to the best of our knowledge, no systematic review to date has identified and synthesized the available evidence on the use of wearable devices to objectively measure the physical activity or sedentary behavior of patients with axSpA.

Objective

This study aimed to review the literature on the use of wearable activity trackers as outcome measures for physical activity and sedentary behavior in patients with axSpA.

Methods

PubMed, PEDro, and Cochrane electronic databases were searched in July 2021 for relevant original articles, with no limits on publication dates. Studies were included if they were original articles, targeted adults with a diagnosis of axSpA, and reported wearable device–measured physical activity or sedentary behavior among patients with axSpA. Data regarding the study’s characteristics, the sample description, the methods used for measuring physical activity and sedentary behavior (eg, wearable devices, assessment methods, and outcomes), and the main results of the physical activity and sedentary behavior assessments were extracted.

Results

A total of 31 studies were initially identified; 13 (13/31, 42%) met the inclusion criteria, including 819 patients with axSpA. All the studies used accelerometer-based wearable devices to assess physical activity. Of the 13 studies, 4 (4/31, 31%) studies also reported outcomes related to sedentary behavior. Wearable devices were secured on the wrists (3/13 studies, 23%), lower back (3/13, 23%), right hip (3/13, 23%), waist (2/13, 15%), anterior thigh (1/13, 8%), or right arm (1/13, 8%). The methods for reporting physical activity and sedentary behavior were heterogeneous. Approximately 77% (10/13) of studies had a monitoring period of 1 week, including weekend days.

Conclusions

To date, few studies have used wearable devices to quantify the physical activity and sedentary behavior of patients with axSpA. The methodologies and results were heterogeneous, and none of these studies assessed the psychometric properties of these wearables in this specific population. Further investigation in this direction is needed before using wearable device–measured physical activity and sedentary behavior as outcome measures in intervention studies in patients with axSpA.

Trial Registration

PROSPERO CRD42020182398; https://tinyurl.com/ec22jzkt

International Registered Report Identifier (IRRID)

RR2-10.2196/23359

Correlates of physical activity in adults with spondyloarthritis and rheumatoid arthritis: a systematic review

Physical activity (PA) is a primary non-pharmacological treatment option for those living with rheumatoid arthritis (RA) and spondyloarthritis (SpA). The aim of this systematic literature review was to summarize and present an updated synthesis of the factors associated with PA in the RA and SpA populations. A tailored search of PubMed (inc. Medline), Web of Science, Embase, APA PsycNET, and Scopus was conducted for research published between 2004 and June 2019. Methodological quality was assessed using The National Institutes of Health (NIH) Quality Assessment Tools for Observational Cohort and Cross-sectional Studies, Case–Control Studies, and Controlled Intervention Studies. Forty RA and eleven SpA articles met the inclusion criteria. Methodological quality was generally fair to good, with two RA studies rated as poor. Correlates are discussed in the sociodemographic, physical, psychological, social, and environmental categories. Environmental factors were not measured in any RA study. In individuals living with RA, consistent positive associations were found between PA and high-density lipoprotein, self-efficacy, and motivation. Consistent negative associations were found for functional disability and fatigue. In individuals with SpA, consistent positive associations were found between PA and quality of life, and consistent negative associations with functional disability. Physical and psychological factors are most consistently related with PA parameters in those living with RA and SpA. Many variables were inconsistently studied and showed indeterminant associations. Studies with prospective designs are needed to further understand the factors associated with PA in these populations, especially in those living with SpA.

Searching for New Genetic Biomarkers of Axial Spondyloarthritis

Background: Axial spondyloarthritis (axSpA) is a chronic inflammatory condition of the spine. In addition to musculoskeletal symptoms, there are also extra-articular manifestations. The aim of this study was to search for new biomarkers associated with the clinical presentation and treatment response in axSpA patients. Methods: In this study, 106 axSpA patients and 110 healthy controls were enrolled. Six single-nucleotide polymorphisms (SNPs) were selected for genotyping: ERAP1 rs2287987, ERAP2 rs2549782, TNF rs1800629, TNFRSF1A rs767455, TNFRSF1B rs1061622, and FCGR2A rs1801274. Participants were examined at baseline and after 12 and 24 weeks of anti-TNF therapy. Results: SNPs associated with high axSpA initial activity were TNFRSF1A rs767455 and TNFRSF1B rs1061622 (p < 0.008). The ERAP1 rs2287987 AA genotype was more frequently observed in patients with enthesitis (AA vs. G+, p = 0.049), while the TNFRSF1B rs1061622 GG genotype was more common in participants with uveitis (GG vs. TT, p = 0.042). Potential in predicting anti-TNF treatment response was demonstrated by ERAP1 rs2287987, ERAP2 rs2549782, TNFRSF1B rs1061622, and FCGR2A rs1801274. Conclusions: SNPs can be used to identify patients at risk of severe disease to initiate treatment earlier. Genetic testing will allow clinicians to choose the right drug for the patient.

Delayed treatment with a tumor necrosis factor alpha blocker associated with worse outcomes in patients with spondyloarthritis: data from the Czech National Registry ATTRA

Introduction:

The administration of biologic disease-modifying antirheumatic drugs, including tumor necrosis factor (TNF)-α inhibitors, is observed to interfere with the disease activity and progression. In this study, we aimed to assess the effectiveness and response predictors of adalimumab (ADA), a TNF-α blocker, in patients with axial spondyloarthritis (AxSpA).

Methods:

This study was a historical prospective, registry-based observational study on patients with AxSpA treated with first-line ADA after conventional drug failure. For evaluation and comparison, patients were divided into three groups according to the number of years from AxSpA diagnosis to initiation of ADA treatment: (A) <5 years, (B) 5–10 years, and (C) >10 years. The assessment instruments ankylosing spondylitis disease activity score (ASDAS), Bath ankylosing spondylitis activity index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), health assessment questionnaire (HAQ), Short Form 36 questionnaire (SF-36), and EuroQoL 5 dimension questionnaire (EQ-5D) were regularly administered for up to 24 months of follow-up.

Results:

This study included 1043 patients with AxSpA (9.2% with non-radiographic AxSpA, 68.9% men). By month 6, a significantly higher proportion of patients with ASDAS remission (<1.3) was achieved upon earlier intervention in group A (30.1%) and B (32.9%) than in the late intervention group C (22.6%) (p ⩽ 0.05). At month 6, lower age and better BASFI at treatment initiation were identified as the strongest predictors of ASDAS remission in both univariable [odds ratio (OR): 0.956, p ⩽ 0.001; OR: 0.834, p ⩽ 0.001, respectively] and multivariable analyses (OR: 0.963, p ⩽ 0.001; OR: 0.859, p ⩽ 0.001, respectively). Earlier intervention also led to improvement in most patient-reported outcomes (PROs) based on HAQ, SF-36, and EQ-5D.

Conclusion:

Results from the ATTRA registry concur with previous clinical trials that supported efficacy of TNF-α blockers and showed better treatment outcomes with early interventions, including reduction of disease activity and improvement in PROs. We identified age and BASFI as the main factors influencing treatment effectiveness.

[Spondyloarthritis in childhood and adulthood]

Axial spondylarthritis in adulthood (SpAA) is frequently initially manifested as a sacroiliitis, whereas this not true for enthesitis-related arthritis (EAA), which begins in childhood and adolescence. Classically, EAA begins with peripheral arthritis and only a part transitions into a juvenile SpA (jSpA) or SpAA. The criteria used for classification of SpAA and EAA are currently being validated and revised. For the first time imaging is included for EAA. For both diseases nonsteroidal anti-inflammatory drugs (NSAID) are initially used therapeutically, followed by biologicals or synthetic targeted disease-modifying drugs in refractory courses. Steroids should be avoided in long-term treatment. For optimal transition and further care in adulthood, a close cooperation between internistic and pediatric rheumatologists is necessary.

Anti-Osteogenic Effect of Danshensu in Ankylosing Spondylitis: An in Vitro Study Based on Integrated Network Pharmacology

Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized by abnormal bone metabolism, with few effective treatments available. Danshensu [3-(3,4-dihydroxy-phenyl) lactic acid) is a bioactive compound from traditional Chinese medicine with a variety of pharmacologic effects. In the present study, we investigated the pharmacologic effect and molecular mechanism of Danshensu in AS. Potential targets of Danshensu were identified in four drugs-genes databases; and potential pharmacologic target genes in AS were identified in three diseases-genes databases. Differentially expressed genes related to AS were obtained from the Gene Expression Omnibus database. Overlapping targets of Danshensu and AS were determined and a disease–active ingredient–target interaction network was constructed with Cytoscape software. Enrichment analyses of the common targets were performed using Bioconductor. To test the validity of the constructed network, an in vitro model was established by treating osteoblasts from newborn rats with low concentrations of tumor necrosis factor (TNF)-α. Then, the in vitro model and AS fibroblasts were treated with Danshensu (1–10 μM). Osteogenesis was evaluated by alkaline phosphatase staining and activity assay, alizarin red staining, quantitative PCR, and western blotting. We identified 2944 AS-related genes and 406 Danshensu targets, including 47 that were common to both datasets. The main signaling pathways associated with the targets were the c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) pathways. A low concentration of TNF-α (0.01 ng/ml) promoted the differentiation of osteoblasts; this was inhibited by Danshensu, which had the same effect on AS fibroblasts but had the opposite effect on normal osteoblasts. Danshensu also decreased the phosphorylation of JNK and ERK in AS fibroblasts. There results provide evidence that Danshensu exerts an anti-osteogenic effect via suppression of JNK and ERK signaling, highlighting its therapeutic potential for the treatment of AS.

The Risk of Cardiovascular Diseases in Axial Spondyloarthritis. Current Insights

There is an increased cardiovascular (CV) risk in axial spondyloarthritis (axSpA), leading to increased CV mortality and morbidity in these patients. The factors that may explain this enhanced CV risk in axSpA are multiple, including traditional CV risk factors such as smoking, but also the inflammatory process and probably the use of non-steroidal anti-inflammatory drugs (NSAIDs). The CV involvement of axSpA may be detected at an early and pre-clinical stage, using non-invasive techniques. While NSAIDs play a deleterious role in the CV risk of axSpA, TNF inhibitors seem to have a beneficial impact, but this remains to be demonstrated in specific clinical studies. More data are needed to determine the potential effects of IL-17 inhibitors on the CV risk of axSpA. CV comorbidity has been mainly assessed in the radiographic form of axSpA, while limited data are available in patients with the non-radiographic form. The current management of axSpA must consider this CV comorbidity according to the EULAR recommendations. Rheumatologists play a determinant role in the detection of CV risk and current management of these patients is focused on the control of disease activity, suppression of inflammation, screening for and management of traditional CV risk factors, as well as the restriction of NSAID use.

Treatment Satisfaction and Decision-making from the Patient Perspective in Axial Spondyloarthritis: Real-World Data from a Descriptive Cross-sectional Survey Study from the ArthritisPower Registry

Objective

Aims were to 1) to characterize patient decision‐making with treatment for axial spondyloarthritis (axSpA) and 2) to explore relationships among decision‐making, treatment satisfaction, and biologic disease modifying antirheumatic drugs (bDMARDs).

Methods

ArthritisPower participants with physician‐diagnosed axSpA were invited to complete an online survey about their treatment and their most recent physician visit. Analysis compared treatment decision by satisfaction and bDMARD status.

Results

Among the 274 participants, 87.2% were female, and the mean age was 50 years. Of participants, 79.5% had researched treatment before their most recent physician visit, and 56.9% discussed treatment change at their most recent physician visit. Of treatment‐change discussions, 69.2% of them were related to escalation, compared with deescalation (27.6%) and/or switching (39.1%). Among those participants who discussed a change, 73.7% agreed to it because they felt that their disease was not being controlled (54.9%) or felt that it could be better controlled on new treatment (20.3%). Top symptoms prompting change were back/buttock pain (63.3%), other joint pain (55.1%), and fatigue (54.1%). Among bDMARD‐treated participants (n = 128), important factors for treatment decisions were prevention of long‐term axSpA consequences (92.9%) and doctor's advice (87.5%). Among 43.4% of participants reporting treatment dissatisfaction, 37% did not discuss treatment change. Current bDMARD use was more common in satisfied (61.9%) than dissatisfied participants (26.9%).

Conclusion

In this cross‐sectional study of a predominantly female axSpA population, patients frequently researched treatment options and discussed escalation with their providers. Under two‐thirds of participants who were dissatisfied with treatment discussed changes at their most recent visit. Current bDMARD use was associated with higher satisfaction, and bDMARD users considered prevention of long‐term consequences and doctor's advice to be very important for decision‐making.

Value-Based Healthcare in Rheumatology: Axial Spondyloarthritis and Beyond

PURPOSE OF REVIEW

This review examines axial spondyloarthritis (axSpA) and the wider field of rheumatology through a value-based healthcare (VBHC) lens. VBHC is focused on ensuring patients receive high quality care to improve outcomes and reduce unnecessary costs.

RECENT FINDINGS

There are many opportunities to apply the principles of VBHC in axSpA. These include the appropriate utilization of diagnostic investigations, such as HLA-B27 and magnetic resonance imaging, assessing outcomes meaningful to patients, and optimizing care pathways. Multidisciplinary care may improve value, and reduced specialist review and medication tapering may be appropriate. Increasing the value of the care we provide to patients can occur across domains and directly and indirectly improves patient outcomes. Taking the time to integrate principles of VBHC into our practice will allow us to justifiably gain and maintain access to diagnostic and therapeutic advances for the benefit of all our patients.

Tofacitinib for the treatment of ankylosing spondylitis: a phase III, randomised, double-blind, placebo-controlled study

OBJECTIVE

To assess the efficacy/safety of tofacitinib in adult patients with active ankylosing spondylitis (AS).

METHODS

This phase III, randomised, double-blind, placebo-controlled study enrolled patients aged ≥18 years diagnosed with active AS, meeting the modified New York criteria, with centrally read radiographs, and an inadequate response or intolerance to ≥2 non-steroidal anti-inflammatory drugs. Patients were randomised 1:1 to receive tofacitinib 5 mg two times per day or placebo for 16 weeks. After week 16, all patients received open-label tofacitinib until week 48. The primary and key secondary endpoints were Assessment of SpondyloArthritis international Society ≥20% improvement (ASAS20) and ≥40% improvement (ASAS40) responses, respectively, at week 16. Safety was assessed throughout.

RESULTS

269 patients were randomised and treated: tofacitinib, n=133; placebo, n=136. At week 16, the ASAS20 response rate was significantly (p<0.0001) greater with tofacitinib (56.4%, 75 of 133) versus placebo (29.4%, 40 of 136), and the ASAS40 response rate was significantly (p<0.0001) greater with tofacitinib (40.6%, 54 of 133) versus placebo (12.5%, 17 of 136). Up to week 16, with tofacitinib and placebo, respectively, 73 of 133 (54.9%) and 70 of 136 (51.5%) patients had adverse events; 2 of 133 (1.5%) and 1 of 136 (0.7%) had serious adverse events. Up to week 48, with tofacitinib, 3 of 133 (2.3%) patients had adjudicated hepatic events, 3 of 133 (2.3%) had non-serious herpes zoster, and 1 of 133 (0.8%) had a serious infection; with placebo→tofacitinib, 2 (1.5%) patients had non-serious herpes zoster. There were no deaths, malignancies, major adverse cardiovascular events, thromboembolic events or opportunistic infections.

CONCLUSIONS

In adults with active AS, tofacitinib demonstrated significantly greater efficacy versus placebo. No new potential safety risks were identified.

TRIAL REGISTRATION NUMBER

NCT03502616.

Tenascin-C-mediated suppression of extracellular matrix adhesion force promotes entheseal new bone formation through activation of Hippo signalling in ankylosing spondylitis

Objectives

The aim of this study was to identify the role of tenascin-C (TNC) in entheseal new bone formation and to explore the underlying molecular mechanism.

Methods

Ligament tissue samples were obtained from patients with ankylosing spondylitis (AS) during surgery. Collagen antibody-induced arthritis and DBA/1 models were established to observe entheseal new bone formation. TNC expression was determined by immunohistochemistry staining. Systemic inhibition or genetic ablation of TNC was performed in animal models. Mechanical properties of extracellular matrix (ECM) were measured by atomic force microscopy. Downstream pathway of TNC was analysed by RNA sequencing and confirmed with pharmacological modulation both in vitro and in vivo. Cellular source of TNC was analysed by single-cell RNA sequencing (scRNA-seq) and confirmed by immunofluorescence staining.

Results

TNC was aberrantly upregulated in ligament and entheseal tissues from patients with AS and animal models. TNC inhibition significantly suppressed entheseal new bone formation. Functional assays revealed that TNC promoted new bone formation by enhancing chondrogenic differentiation during endochondral ossification. Mechanistically, TNC suppressed the adhesion force of ECM, resulting in the activation of downstream Hippo/yes-associated protein signalling, which in turn increased the expression of chondrogenic genes. scRNA-seq and immunofluorescence staining further revealed that TNC was majorly secreted by fibroblast-specific protein-1 (FSP1)+fibroblasts in the entheseal inflammatory microenvironment.

Conclusion

Inflammation-induced aberrant expression of TNC by FSP1+fibroblasts promotes entheseal new bone formation by suppressing ECM adhesion forces and activating Hippo signalling.

Role of the IL-23/IL-17 Pathway in Rheumatic Diseases: An Overview

Interleukin-23 (IL-23) is a pro-inflammatory cytokine composed of two subunits, IL-23A (p19) and IL-12/23B (p40), the latter shared with Interleukin-12 (IL-12). IL-23 is mainly produced by macrophages and dendritic cells, in response to exogenous or endogenous signals, and drives the differentiation and activation of T helper 17 (Th17) cells with subsequent production of IL-17A, IL-17F, IL-6, IL-22, and tumor necrosis factor α (TNF-α). Although IL-23 plays a pivotal role in the protective immune response to bacterial and fungal infections, its dysregulation has been shown to exacerbate chronic immune-mediated inflammation. Well-established experimental data support the concept that IL-23/IL-17 axis activation contributes to the development of several inflammatory diseases, such as PsA, Psoriasis, Psoriatic Arthritis; AS, Ankylosing Spondylitis; IBD, Inflammatory Bowel Disease; RA, Rheumatoid Arthritis; SS, Sjogren Syndrome; MS, Multiple Sclerosis. As a result, emerging clinical studies have focused on the blockade of this pathogenic axis as a promising therapeutic target in several autoimmune disorders; nevertheless, a greater understanding of its contribution still requires further investigation. This review aims to elucidate the most recent studies and literature data on the pathogenetic role of IL-23 and Th17 cells in inflammatory rheumatic diseases.

Skin manifestations in spondyloarthritis

Spondyloarthritides (SpA) like psoriatic arthritis, axial spondyloarthritis/ankylosing spondylitis, reactive arthritis and inflammatory bowel disease (IBD)-associated SpA can present with characteristic skin manifestations. These SpA-associated skin disorders may precede joint involvement, reflect a loss of efficacy of a current systemic treatment or can even be treatment associated. Cutaneous manifestations in SpA not only add additional morbidity with physical impact but also impose a psychosocial burden on affected patients. Psoriasis (PsO) - the main skin disease in SpA - has a variety of clinical presentations, including plaque-type PsO, inverse PsO, guttate PsO, erythrodermic PsO, nail PsO and pustular types. SpA associated with IBD presents with neutrophilic and granulomatous skin disorders, including pyoderma gangrenosum, hidradenitis suppurativa and cutaneous Crohn's disease. Reactive arthritides has a favourable prognosis and may feature keratoderma blenorrhagicum or balanitis circinatum as typical skin manifestations. Immunologically, SpA-associated skin diseases share interleukin (IL)-17 and IL-23 dysregulation but show distinctive genetic and immunological profiles. Therefore, they vary in their treatment responses to targeted therapies with biologicals or small molecules. In this review, we highlight the clinical presentation of skin manifestations in SpA and discuss therapeutic approaches in this interdisciplinary field.