HLA-B27.

Possession of the human leukocyte antigen (HLA) class I molecule B27 is strongly associated with ankylosing spondylitis (AS), but the pathogenic role of HLA-B27 is unknown. Two broad theories most likely explain the role of HLA-B27 in AS pathogenesis. The first is based on the natural immunological function of HLA-B27 of presenting antigenic peptides to cytotoxic T cells. Thus, HLA-B27-restricted immune responses to self-antigens, or arthritogenic peptides, might drive immunopathology. B27 can also "behave badly," misfolding during assembly and leading to endoplasmic reticulum stress and autophagy responses. ß2m-free B27 heavy chain structures including homodimers (B272) can also be expressed at the cell surface following endosomal recycling of cell surface heterotrimers. Cell surface free heavy chains and B272 bind to innate immune receptors on T, NK, and myeloid cells with proinflammatory effects. This review describes the natural function of HLA-B27, its disease associations, and the current theories as to its pathogenic role.

Cellular and molecular diversity in spondyloarthritis.

The spondyloarthritides are a cluster of inflammatory rheumatic diseases characterized by different diagnostic entities with heterogeneous phenotypes. The current classification system groups spondyloarthritis patients in two main categories, axial and peripheral spondyloarthritis, providing a framework wherein the clinical picture guides the treatment. However, the heterogeneity of the clinical manifestations of the pathologies, even when residing in the same group, highlights the importance of analyzing the smallest features of each entity to understand how different cellular subsets evolve, what the underlying mechanisms are and what biological markers can be identified and validated to evaluate the stage of disease and the corresponding efficacy of treatments. In this review, we will focus mostly on axial spondyloarthritis, report current knowledge concerning the cellular populations involved in its pathophysiology, and their molecular diversity. We will discuss the implications of such a diversity, and their meaning in terms of patients' stratification.

Development of international consensus on a standardised image acquisition protocol for diagnostic evaluation of the sacroiliac joints by MRI: an ASAS-SPARTAN collaboration.

BACKGROUND: A range of sacroiliac joint (SIJ) MRI protocols are used in clinical practice but not all were specifically designed for diagnostic ascertainment. This can be confusing and no standard diagnostic SIJ MRI protocol is currently accepted worldwide. OBJECTIVE: To develop a standardised MRI image acquisition protocol (IAP) for diagnostic ascertainment of sacroiliitis. METHODS: 13 radiologist members of Assessment of SpondyloArthritis International Society (ASAS) and the SpondyloArthritis Research and Treatment Network (SPARTAN) plus two rheumatologists participated in a consensus exercise. A draft IAP was circulated with background information and online examples. Feedback on all issues was tabulated and recirculated. The remaining points of contention were resolved and the revised IAP was presented to the entire ASAS membership. RESULTS: A minimum four-sequence IAP is recommended for diagnostic ascertainment of sacroiliitis and its differential diagnoses meeting the following requirements. Three semicoronal sequences, parallel to the dorsal cortex of the S2 vertebral body, should include sequences sensitive for detection of (1) changes in fat signal and structural damage with T1-weighting; (2) active inflammation, being T2-weighted with fat suppression; (3) bone erosion optimally depicting the bone-cartilage interface of the articular surface and (4) a semiaxial sequence sensitive for detection of inflammation. The IAP was approved at the 2022 ASAS annual meeting with 91% of the membership in favour. CONCLUSION: A standardised IAP for SIJ MRI for diagnostic ascertainment of sacroiliitis is recommended and should be composed of at least four sequences that include imaging in two planes and optimally visualise inflammation, structural damage and the bone-cartilage interface.

Low uveitis rates in patients with axial spondyloarthritis treated with bimekizumab: pooled results from phase 2b/3 trials.

OBJECTIVES: Acute anterior uveitis ('uveitis') is a common axial spondyloarthritis (axSpA) extramusculoskeletal manifestation. Interleukin (IL)-17 is implicated in its pathogenesis, however, there is conflicting evidence for IL-17A inhibition in uveitis management. We report pooled analyses of uveitis incidence in patients receiving bimekizumab (BKZ), a monoclonal IgG1 antibody that selectively inhibits IL-17F in addition to IL-17A, from phase 2b/3 trials. METHODS: Data were pooled for patients receiving BKZ 160 mg or placebo in the double-blind treatment period of the phase 3 BE MOBILE 1 (NCT03928704; non-radiographic axSpA) and BE MOBILE 2 (NCT03928743; radiographic axSpA) trials. Data were separately pooled for patients treated with at least one BKZ dose in the BE MOBILE trials and their ongoing open-label extension (OLE; NCT04436640), and the phase 2b BE AGILE trial (NCT02963506; radiographic axSpA) and its ongoing OLE (NCT03355573). Uveitis rates and exposure-adjusted incidence rates (EAIR)/100 patient-years (PYs) are reported. RESULTS: In the BE MOBILE 1 and 2 double-blind treatment period, 0.6% (2/349) of patients receiving BKZ experienced uveitis vs 4.6% (11/237) receiving placebo (nominal p=0.001; EAIR (95% CI): 1.8/100 PYs (0.2 to 6.7) vs 15.4/100 PYs (95% CI 7.7 to 27.5)). In patients with history of uveitis, EAIR was lower in patients receiving BKZ (6.2/100 PYs (95% CI 0.2 to 34.8); 1.9%) vs placebo (70.4/100 PYs (95% CI 32.2 to 133.7); 20.0%; nominal p=0.004). In the phase 2b/3 pool (N=848; BKZ exposure: 2034.4 PYs), EAIR remained low (1.2/100 PYs (95% CI 0.8 to 1.8)). CONCLUSIONS: Bimekizumab, a dual-IL-17A/F inhibitor, may confer protective effects for uveitis in patients with axSpA.

Performance analysis of a deep-learning algorithm to detect the presence of inflammation in MRI of sacroiliac joints in patients with axial spondyloarthritis.

OBJECTIVES: To assess the ability of a previously trained deep-learning algorithm to identify the presence of inflammation on MRI of sacroiliac joints (SIJ) in a large external validation set of patients with axial spondyloarthritis (axSpA). METHODS: Baseline SIJ MRI scans were collected from two prospective randomised controlled trials in patients with non-radiographic (nr-) and radiographic (r-) axSpA (RAPID-axSpA: NCT01087762 and C-OPTIMISE: NCT02505542) and were centrally evaluated by two expert readers (and adjudicator in case of disagreement) for the presence of inflammation by the 2009 Assessment of SpondyloArthritis International Society (ASAS) definition. Scans were processed by the deep-learning algorithm, blinded to clinical information and central expert readings. RESULTS: Pooling the patients from RAPID-axSpA (n=152) and C-OPTIMISE (n=579) yielded a validation set of 731 patients (mean age: 34.2 years, SD: 8.6; 505/731 (69.1%) male), of which 326/731 (44.6%) had nr-axSpA and 436/731 (59.6%) had inflammation on MRI per central readings. Scans were obtained from over 30 scanners from 5 manufacturers across over 100 clinical sites. Comparing the trained algorithm with the human central readings yielded a sensitivity of 70% (95% CI 66% to 73%), specificity of 81% (95% CI 78% to 84%), positive predictive value of 84% (95% CI 82% to 87%), negative predictive value of 64% (95% CI 61% to 68%), Cohen's kappa of 0.49 (95% CI 0.43 to 0.55) and absolute agreement of 74% (95% CI 72% to 77%). CONCLUSION: The algorithm enabled acceptable detection of inflammation according to the 2009 ASAS MRI definition in a large external validation cohort.

Unmet need in rheumatology: reports from the Advances in Targeted Therapies meeting, 2023.

The Advances in Targeted Therapies meets annually, convening experts in the field of rheumatology to both provide scientific updates and identify existing scientific gaps within the field. To review the major unmet scientific needs in rheumatology. The 23rd annual Advances in Targeted Therapies meeting convened with more than 100 international basic scientists and clinical researchers in rheumatology, immunology, infectious diseases, epidemiology, molecular biology and other specialties relating to all aspects of immune-mediated inflammatory diseases. We held breakout sessions in five rheumatological disease-specific groups including: rheumatoid arthritis (RA), psoriatic arthritis (PsA), axial spondyloarthritis (axSpa), systemic lupus erythematosus (SLE), systemic sclerosis (SSc) and vasculitis, and osteoarthritis (OA). In each group, experts were asked to identify and prioritise current unmet needs in clinical and translational research. An overarching theme across all disease states is the continued need for clinical trial design innovation with regard to therapeutics, endpoint and disease endotypes. Within RA, unmet needs comprise molecular classification of disease pathogenesis and activity, pre-/early RA strategies, more refined pain profiling and innovative trials designs to deliver on precision medicine. Continued scientific questions within PsA include evaluating the genetic, immunophenotypic, clinical signatures that predict development of PsA in patients with psoriasis, and the evaluation of combination therapies for difficult-to-treat disease. For axSpA, there continues to be the need to understand the role of interleukin-23 (IL-23) in pathogenesis and the genetic relationship of the IL-23-receptor polymorphism with other related systemic inflammatory diseases (eg, inflammatory bowel disease). A major unmet need in the OA field remains the need to develop the ability to reliably phenotype and stratify patients for inclusion in clinical trials. SLE experts identified a number of unmet needs within clinical trial design including the need for allowing endpoints that reflect pharmacodynamic/functional outcomes (eg, inhibition of type I interferon pathway activation; changes in urine biomarkers). Lastly, within SSc and vasculitis, there is a lack of biomarkers that predict response or disease progression, and that allow patients to be stratified for therapies. There remains a strong need to innovate clinical trial design, to identify systemic and tissue-level biomarkers that predict progression or response to therapy, endotype disease, and to continue developing therapies and therapeutic strategies for those with treatment-refractory disease. This document, based on expert consensus, should provide a roadmap for prioritising scientific endeavour in the field of rheumatology.

Clinical information on imaging referrals for suspected or known axial spondyloarthritis: recommendations from the Assessment of Spondyloarthritis International Society (ASAS).

OBJECTIVES: This study aims to establish expert consensus recommendations for clinical information on imaging requests in suspected/known axial spondyloarthritis (axSpA), focusing on enhancing diagnostic clarity and patient care through guidelines. MATERIALS AND METHODS: A specialised task force was formed, comprising 7 radiologists, 11 rheumatologists from the Assessment of Spondyloarthritis International Society (ASAS) and a patient representative. Using the Delphi method, two rounds of surveys were conducted among ASAS members. These surveys aimed to identify critical elements for imaging referrals and to refine these elements for practical application. The task force deliberated on the survey outcomes and proposed a set of recommendations, which were then presented to the ASAS community for a decisive vote. RESULTS: The collaborative effort resulted in a set of six detailed recommendations for clinicians involved in requesting imaging for patients with suspected or known axSpA. These recommendations cover crucial areas, including clinical features indicative of axSpA, clinical features, mechanical factors, past imaging data, potential contraindications for specific imaging modalities or contrast media and detailed reasons for the examination, including differential diagnoses. Garnering support from 73% of voting ASAS members, these recommendations represent a consensus on optimising imaging request protocols in axSpA. CONCLUSION: The ASAS recommendations offer comprehensive guidance for rheumatologists in requesting imaging for axSpA, aiming to standardise requesting practices. By improving the precision and relevance of imaging requests, these guidelines should enhance the clinical impact of radiology reports, facilitate accurate diagnosis and consequently improve the management of patients with axSpA.

Exploring the unifying concept of Spondyloarthritis: a latent class analysis of the REGISPONSER registry.

OBJECTIVES: The aim of our study is to identify the potential distinct phenotypes within a broad Spondyloarthritis (SpA) population. METHODS: We conducted a cross-sectional study using the REGISPONSER registry with data from 31 specialist centres in Spain including patients with SpA who fulfilled the European Spondyloarthropathy Study Group (ESSG) criteria. A latent class analysis (LCA) was performed to identify the latent classes underlying SpA according to a set of predefined clinical and radiographic features, independently of expert opinion. RESULTS: In a population of 2319 SpA patients, a 5 classes LCA model yielded the best fit. Classes named 'axial with spine involvement' and 'axial with isolated SIJ involvement" show a primarily axial SpA phenotype defined by inflammatory back pain and high HLA-B27 prevalence. Patients in class 'axial + peripheral' show similar distribution of manifest variables to previous classes but also have a higher likelihood of peripheral involvement (peripheral arthritis/dactylitis) and enthesitis, therefore representing a mixed (axial and peripheral) subtype. Classes 'Peripheral + psoriasis' and 'Axial + peripheral + psoriasis' are indicative of peripheral SpA (and/or PsA) with high likelihood of psoriasis, peripheral involvement, dactylitis, nail disease, and low HLA-B27 prevalence, while class 'Axial + peripheral + psoriasis' also exhibits increased probability of axial involvement both clinically and radiologically. CONCLUSION: The identification of 5 latent classes in the REGISPONSER registry with significant overlap between axial and peripheral phenotypes is concordant with a unifying concept of SpA. Psoriasis and related features (nail disease and dactylitis) influence the phenotype of both axial and peripheral manifestations.

Intestinal epithelial expression of human TNF is sufficient to induce small bowel inflammation and sacroiliitis mimicking human Spondyloarthritis.

OBJECTIVES: Gut and joint disease commonly co-occur in spondyloarthritis (SpA). Up to 50% of SpA-patients show signs of subclinical gut inflammation and 10% evolves into inflammatory bowel disease (IBD). However, the mechanisms underlying this gut-joint axis are still unclear. Here we tested the hypothesis whether restricted expression of a pro-inflammatory cytokine in the intestine may trigger onset of combined gut and joint inflammation. METHODS: Intestinal expression of human TNF (hTNF) was achieved by driving hTNF gene expression under control of the rat FAPB2 promoter, creating a new animal model, the TNFgut mice, which expresses hTNF in the proximal intestinal tract. Intestinal-specific TNFgut mice were examined for pathological changes in the intestine and extra-intestinal tissues by means of histology, qPCR and flow cytometry, along with 16S sequencing on stools. RESULTS: Local expression of hTNF in the epithelium of the small intestine induces a pro-inflammatory state of the proximal intestinal tract with epithelial alterations and induction of members of the S100 family, as well as local upregulation of T helper 17 and regulatory T cells, but no obvious signs of dysbiosis. Curiously, TNFgut mice develop sacroiliitis (p< 0.05) in addition to small bowel inflammation (p< 0.05). However, no signs of peripheral arthritis nor enthesitis could be documented. CONCLUSION: Intestinal expression of hTNF is sufficient to initiate a pro-inflammatory cascade culminating in small bowel inflammation and sacroiliitis. Thus, gut-derived cytokines are sufficient to induce spondyloarthritis.

HLA-B5 prevalence in patients with spondyloarthritis and impact on disease phenotype: a multicentric case-control study.

OBJECTIVE: The study aimed to estimate the prevalence of HLA-B51 and HLA-B52 in Lebanese patients with spondyloarthritis (SpA) compared to healthy controls (HC). We further aimed to evaluate the impact of HLA-B51 on phenotype and identify the distribution of the alleles in the HLA-B locus. METHODS: A case-control study enrolled consecutive SpA patients from three rheumatology clinics in Lebanon, including axial (axSpA), peripheral SpA (pSpA), and psoriatic arthritis (PsA) and HC from blood donors. Demographic and disease data were collected through interviews and file reviews, with testing of the entire HLA-B locus using molecular techniques. The prevalence of HLA-B51 and B52 was estimated in SpA patients versus controls. Prevalence comparisons were made, and logistic regression identified factors associated with HLA-B51 in patients. RESULTS: Data from 120 HC and 86 SpA patients (65 axSpA, 15 pSpA, 6 PsA), mean age 25.6 and 46.4 years, respectively, showed a higher HLA-B51 prevalence in SpA (25.6%), especially axSpA (29.2%) versus HC (12.5%), p = 0.016, and a numerically higher HLA-B52 prevalence (8.1% versus 4.2%, p = 0.230). HLA-B51 correlated with recurrent oral ulcerations (OR 7.99(95%CI 2.14-29.84) and radiographic juxta-articular erosions (OR 7.65(95%CI 1.14-38.03)). HLA-B35 was the most dominant allele in both groups (18.7%), followed by HLA-B27 (15.7%) and HLA-B51 (13.4%) in SpA. CONCLUSION: HLA-B51 was identified more frequently in patients with SpA compared to HC and was associated with recurrent oral ulcerations and juxta-articular radiographic erosions. Longitudinal studies are needed to determine whether this association indicates a disease overlap or might correlate with a specific SpA phenotype.

The association between sonographic enthesitis with sonographic synovitis and tenosynovitis in psoriatic arthritis patients.

OBJECTIVES: To examine the association between sonographic enthesitis with sonographic synovitis and tenosynovitis in PsA patients, and the association between sonographic enthesitis and clinical characteristics. METHODS: Consecutive PsA patients that fulfilled the ClASsification criteria for Psoriatic ARthritis (CASPAR) were prospectively recruited. Each patient was evaluated by comprehensive clinical and sonographic assessment (greyscale and Doppler), the latter including 52 joints, 40 tendons and 14 entheses [according to MAdrid Sonography Enthesitis Index (MASEI) plus lateral epicondyles] performed by an experienced sonographer blinded to the clinical data. The US enthesitis score was further categorized to inflammatory (hypoechogenicity, thickening, bursitis and Doppler) and structural (enthesophytes/calcifications and erosions) subcategories. Multivariate linear regression models assessed the association between enthesitis and the selected variables. RESULTS: A total of 158 PsA patients [mean (s.d.) age 52.3 (13) years, 88 (55.7%) females] were analysed. Multivariate linear regression analyses showed a significant association between sonographic enthesitis and sonographic synovitis (ß = 0.18, P = 0.008) and between sonographic enthesitis and sonographic tenosynovitis (ß = 0.06, P = 0.02). These associations were derived from the enthesitis inflammatory subcategory of the MASEI (P < 0.05). Associations between enthesitis and synovitis were also demonstrated on the level of the elbow, knee and ankle joints (P < 0.05). In addition, sonographic enthesitis was significantly associated with older age, male sex, swollen joint count, CRP level and physical occupation. CONCLUSIONS: Sonographic enthesitis is associated with sonographic synovitis and tenosynovitis. The severity of sonographic enthesitis may represent a marker for inflammatory activity in other musculoskeletal domains.

Treatment decisions in axial spondyloarthritis daily clinical practice are more than treat-to-target.

OBJECTIVE: 'Treat-to-target principles' are advised for axial spondyloarthritis (axSpA), although a clear target is not yet defined and targets do not always reflect inflammation. Treat-to-target use and motives for treatment choices in clinics are unknown. Therefore, we studied the presence of residual disease activity according physician's opinion, patient's opinion and composite indices and compared them to the subsequent treatment decisions. METHODS: This cross-sectional multicentre study included 249 patients with a clinical diagnosis of axSpA ≥6 months. Remission and low disease activity according to the BASDAI (<1.9 and <3.5, respectively) and physician's and patient's opinion were assessed. Questionnaires included patient-reported outcomes and patients and physicians completed questions regarding treatment decisions. RESULTS: A total of 115/249 (46%) patients were in remission according to the physician and 37% (n = 43) of these patients reached remission according to the BASDAI. In 51/83 (60%) of the patients with residual disease activity according to the physician and a BASDAI >3.5 the treatment was left unchanged, either because of low disease activity as rated by the physician [n = 15 (29%)] or because of a combination of low disease activity with non-inflammatory complaints or comorbidities [n = 11 (25%)]. Retrospective treat-to-target evaluations showed that treatments were most frequently intensified in patients with arthritis or inflammatory back pain and less often in patients with other (non-inflammatory) musculoskeletal comorbidities. CONCLUSION: This study shows that physicians do not always strictly apply treat-to-target in case of residual disease activity in axSpA. Usually, they accept low disease activity as satisfactory.

Flare prediction after tapering the dose of tumour necrosis factor inhibitors in patients with axial spondyloarthritis: A nationwide cohort study.

OBJECTIVES: To develop a model for predicting flares after tapering the dose of tumour necrosis factor inhibitors (TNFi) in patients with axial spondyloarthritis (axSpA). METHODS: Data were obtained from the Korean College of Rheumatology Biologics and Targeted Therapy Registry. In total, 526 patients who received the standard-dose TNFi for at least 1 year and tapered their dose were included in the derivation cohort. The main outcome was a flare occurrence defined as an Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) score of ≥ 2.1 after 1 year of TNFi tapering. The final prediction model was validated using an independent cohort. RESULTS: Among 526 patients, 127 (24.1%) experienced flares. The final prediction model included negative human leucocyte antigen B27 (ß = 1.088), inflammatory back pain (ß = 1.072), psoriasis (ß = 1.567), family history of SpA (ß = 0.623), diabetes mellitus (ß = 1.092), TNFi tapering by ≥ 50% of the standard-dose (ß = 0.435), ASDAS-CRP at tapering (ß = 1.029), and Bath Ankylosing Spondylitis Functional Index score at tapering (ß = 0.194) as covariates. It showed an excellent discrimination performance (AUC = 0.828). According to the predictive risk, patients were classified into three groups (low-, intermediate-, and high-risk). The probabilities of flares in these groups were 4.5%, 18.1%, and 61.8%, respectively. The performance of the model in the validation cohort was also comparable. CONCLUSION: The established prediction model accurately predicted the risk of flares after TNFi dose tapering in patients with axSpA using eight simple clinical parameters, which could be helpful to select appropriate patients for tapering their TNFi without flare in daily clinical practice.

Short-term effectiveness of guselkumab in psoriatic arthritis patients and suggestive features of axial involvement: results from a real-life multicentre cohort.

OBJECTIVE: To evaluate the short-term effectiveness of guselkumab in patients with psoriatic arthritis (PsA) and suggestive features of axial involvement in a prospective "real-life" multicentre cohort. METHODS: Between June 2022 and June 2023, PsA patients with axial involvement were evaluated if treated at least for 4 months with guselkumab. The effectiveness was evaluated by BASDAI, ASDAS, DAPSA, and achievement of BASDAI ≤ 4, also exploiting predictive factors. In a group of patients, MRI findings on sacroiliac joints were assessed before and after guselkumab administration. RESULTS: Sixty-seven patients with PsA and suggestive features of axial involvement (age 53.4 ± 11.2 years, male sex 26.9%) were treated with guselkumab. After 4 months, a significant reduction of BASDAI, ASDAS, and DAPSA was observed. A ΔBASDAI of -2.11 ± 0.43 was estimated assessing the mean difference values before and after guselkumab administration and 52.2% of patients reached a BASDAI ≤ 4. In 27 patients, MRI findings on sacroiliac joints were assessed before and after guselkumab administration. A reduction of 0.80 or larger of the sacroiliac joint lesion score was observed in the majority of patients (70.3%) based on MRI improvements, paralleling with the clinical response.No life-threatening side effects were recorded; 17.9% of patients reported minor adverse events mainly injection site reactions. CONCLUSIONS: The short-term effectiveness of guselkumab in patients with PsA and suggestive features of axial involvement was shown. Although further studies are needed, our multicentre "real-life" study may suggest the clinical usability of guselkumab in this context.

Performance of clinical, laboratory and imaging features for diagnosing spondyloarthritis-a systematic literature review and meta-analysis.

OBJECTIVE: The Berlin algorithm was developed to help diagnosing axial spondyloarthritis (axSpA), but new studies suggest some features typical of SpA are less specific than previously assumed. Furthermore, evidence is lacking for other SpA subtypes (e.g. peripheral SpA). We aimed to review the evidence on the performance of SpA features for diagnosing each SpA subtype. METHODS: Systematic literature review of studies reporting the diagnostic performance of ≥ 1 SpA feature in patients with suspected SpA. The external reference was the rheumatologist's diagnosis of SpA. Meta-analysis was performed, separately for each SpA subtype, to estimate pooled sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratios. Meta-regression assessed the effect of covariates (e.g. feature's prevalence) on each feature's performance. RESULTS: Of 13 844 articles screened, 46 were included. Sacroiliitis on magnetic resonance imaging, damage on pelvic radiographs and elevated C-reactive protein (CRP) had the best balance between LR+ and LR- (LR + 3.9-17.0, LR- 0.5-0.7) for diagnosing axSpA. HLA-B27 had an LR+ lower than anticipated (LR + =3.1). Inflammatory back pain (IBP) had low LR + (LR+∼1), but substantially decreased the likelihood of axSpA when absent (LR-=0.3). Conversely, peripheral features and extra-musculoskeletal manifestations showed high LR + (LR+ 1.6-5.0), but were as common in axSpA as no-axSpA (LR-∼1). The specificity of most features was reduced in settings when these were highly prevalent. Limited data precluded a detailed analysis on diagnosing other SpA subtypes. CONCLUSION: Imaging features and CRP have good diagnostic value for axSpA. However, the specificity of other features, especially HLA-B27 and IBP, is lower than previously known.

Regional differences in clinical phenotype of axial spondyloarthritis: results from the International Map of Axial Spondyloarthritis (IMAS).

OBJECTIVES: To explore differences in axial spondyloarthritis (axSpA) clinical phenotype around the world in a large sample of patients included in the International Map of Axial Spondyloarthritis (IMAS). METHOD: IMAS was a cross-sectional online survey (2017-2022) of 5557 unselected axSpA patients from 27 countries. We analysed across five geographic regions the age at symptom onset, diagnostic delay, gender, HLA-B27, family history, extra-musculoskeletal manifestations, presence of comorbidities, disease activity (BASDAI), level of spinal stiffness and treatments. RESULTS: Of 5557 IMAS participants, 3493 were from Europe, 770 from North America, 600 from Asia, 548 from Latin America and 146 from South Africa. Age at symptom onset ranged between 25 and 30 years and was higher in Latin America. Diagnostic delay was longest in South Africa and lowest in Asia. The lowest HLA-B27 positivity was observed in Latin America and the highest in Asia. Extra-musculoskeletal manifestations were the lowest in Europe. Mean disease activity (BASDAI) was 5.4, with highest values in South Africa and lowest in Asia. Most of the patients had used NSAIDs for their condition and less than half had ever taken conventional synthetic DMARDS; both were more frequent in Latin America and South Africa. Almost half of the patients had ever taken biologic DMARDs, more frequent use being in the Americas. CONCLUSION: There is great heterogeneity of axSpA clinical phenotype presentation around the world. AxSpA manifests differently in different regions, so further understanding of these differences of phenotypes is needed to achieve early diagnosis and initiation of optimal disease treatment in axSpA in the different regions.

Thresholds for unacceptable work state in radiographic axial Spondyloarthritis of four presenteeism and two clinical outcome measurement instruments.

OBJECTIVES: To a) identify threshold values of presenteeism measurement instruments that reflect unacceptable work state in employed r-axSpA patients; b) determine whether those thresholds accurately predict future adverse work outcomes (AWO) (sick leave or short/long-term disability); c) evaluate the performance of traditional health-outcomes for r-axSpA; d) explore whether thresholds are stable across contextual factors. METHODS: Data from the multinational AS-PROSE study was used. Thresholds to determine whether patients consider themselves in an 'unacceptable work state' were calculated at baseline for four instruments assessing presenteeism and two health-outcomes specific for r-axSpA. Different approaches derived from the receiver operating characteristic methodology were used. Validity of the optimal thresholds was tested across contextual factors and for predicting future AWO over 12 months. RESULTS: Of 366 working patients, 15% reported an unacceptable work state; 6% experienced at least one AWO in 12 months. Optimal thresholds were: WPAI-presenteeism ≥40 (AUC 0.85), QQ-method <97 (0.76), WALS ≥0.75 (AUC 0.87), WLQ-25 ≥ 29 (AUC 0.85). BASDAI and BASFI performed similarly to the presenteeism instruments: ≥4.7 (AUC 0.82) and ≥3.5 (AUC 0.79), respectively. Thresholds for WALS and WLQ-25 were stable across contextual factors, while for all other instruments they overestimated unacceptable work state in lower educated persons. Proposed thresholds could also predict future AWO, although with lower performance, especially for QQ-method, BASDAI and BASFI. CONCLUSIONS: Thresholds of measurement instruments for presenteeism and health status to identify unacceptable work state have been established. These thresholds can help in daily clinical practice to provide work related support to r-axSpA patients at risk for AWO.

16s RNA-based metagenomics reveal previously unreported gut microbiota associated with reactive arthritis and undifferentiated peripheral spondyloarthritis.

OBJECTIVES: Reactive arthritis (ReA) provides a unique opportunity to comprehend how a mucosal infection leads to inflammatory arthritis at a distant site without the apparent invasion of the pathogen. Unfortunately, conventional stool cultures after ReA provide limited information, and there is a dearth of metagenomic studies in ReA. The objective of this study was to identify gut microbiota associated with the development of ReA. METHODS: Patients with ReA or undifferentiated peripheral spondyloarthritis (UpSpA) were included if they presented within 4 weeks of the onset of the current episode of arthritis. Metagenomic DNA was extracted from the stools of these patients and of 36 age- and sex-similar controls. Sequencing and analysis were done using a standard 16S ribosomal pipeline. RESULTS: Of 55 patients, there was no difference between the gut microbiota of postdiarrheal ReA(n = 20) and of upSpA (n = 35). Comparing the gut microbiota of patients vs healthy controls, the patients had significantly higher alpha and beta diversity measures. After stringency filters, Proteobacteria had high abundance while Firmicutes had lesser as compared with the controls. Six families were overexpressed in patients, while another five were overexpressed in controls. Sixteen genera and 18 species were significantly different between patients and controls. At the species level there was strong association of Staphylococcus aureus, Clostridium septicum Klebsiella pneumoniae, Escherichia coli, Empedobacter brevis, Roseburia hominis, Bacillus velezensis, and Crassaminicella with ReA. CONCLUSION: The microbiota of classical gut-associated ReA and upSpA is similar. Patients have higher diversities in their gut microbiota compared with healthy controls. Both known and previously unreported species associated with ReA/upSpA were identified.

Impact on patient outcomes of spondyloarthritis-inflammatory bowel disease multi-disciplinary meetings.

OBJECTIVES: To assess the impact on patient outcomes of the spondyloarthritis (SpA) and inflammatory bowel disease (IBD) multidisciplinary team (MDT) meetings in a large university hospital. METHODS: A single-centre retrospective observational case-note review was conducted assessing the outcome of all 226 cases discussed at the SpA-IBD MDT meetings in a large UK university hospital between 2017-2022. RESULTS: A total of 226 patients were discussed. It was deemed that 97% of MDT meetings helped to improve communication between teams, and 100% were educational. A total of 57% of discussions led to an instant change of disease management, while 40% of discussions resulted in a treatment plan that avoided the use of dual advanced therapy. This improved patient safety by reducing immunosuppression. The MDT meetings were highly cost and time efficient; 125 referrals between specialists were avoided, and in 51 cases there was a significant chance of reducing future drug costs. A timely investigation or appointment was arranged following 50% of MDT discussions, helping to clarify the diagnosis and optimise patient care. 9% of meetings enabled drugs to be prescribed to patients that are not yet licenced for the other speciality, thereby improving treatment options available in the management of complex cases. CONCLUSION: The MDT meetings have been beneficial for patients, the clinical team and the institution. This approach might be considered by other rheumatology and gastroenterology departments.

Subclinical psoriatic arthritis and disease interception-where are we in 2024?

Psoriatic arthritis (PsA) is a chronic rheumatic disease that usually appears in patients with skin psoriasis, making it a model for detection of joint disease in the pre-clinical phases in a setting where therapy for cutaneous disease may ameliorate or prevent arthritis development. Such PsA prevention appears credible due to the increasingly recognized closely shared immunopathology between the skin and joints, especially the entheses. Recently, several initiatives have explored the concept of pre-clinical PsA, and nomenclatures have been developed with the recent EULAR nomenclature proposing a simplified three stages from psoriasis to clinical PsA development, namely at risk of PsA, subclinical PsA and early PsA. A better comprehension of early PsA and the identification of individuals predisposed to its development could enable interventions to 'prevent' the appearance of PsA. Several recent retrospective observational studies have demonstrated disease interception feasibility, i.e. treatment of people with psoriasis may prevent the appearance of PsA, in particular using biologic disease-modifying drugs. However, further data is urgently required due to unexpected findings in some studies where TNF inhibition for psoriasis does not reduce the rate of PsA development. In this review we address the current challenges in early PsA, including comparisons of pre-PsA nomenclature sets, its risk factors, and the potential for disease interception.