Sex differences in patient-reported outcomes and the association with clinical factors in axial spondyloarthritis patients treated with tumour necrosis factor inhibitors.

OBJECTIVES: To investigate sex differences in patient-reported outcome measures (PROMs) among axSpA patients initiating their first TNFi and identify factors contributing to these disparities over the follow-up. METHODS: Data were included from 15 EuroSpA registries and consisted of axSpA patients initiating their first TNFi, with ≥2 measurements for each analysed PROM (BASDAI and BASFI, scale 0-100) taken at any time point. Linear mixed models were employed to analyse sex differences in PROMs over 24 months and to evaluate how baseline characteristics were related to the observed sex differences. RESULTS: We analysed 13 102 (38% women) in the BASDAI analyses and 10 623 (38% women) in the BASFI analyses. At follow-up, mean sex differences in BASDAI increased from 4.3 units at baseline (95% CI, 3.5-5.1)-8.0 (7.2-8.8) at 6 months, and in BASFI from 2.2 (1.4-3.1)-4.6 (3.6-5.5), with consistently worse scores in women. Baseline characteristics could not substantially account for the observed sex differences over time; however, the magnitude of the sex differences was reduced by HLA-B27 positivity, longer disease duration, and increased CRP levels, but increased by TNFi initiation in later years and peripheral arthritis. CONCLUSION: In axSpA patients initiating their first TNFi, baseline sex differences in BASDAI and BASFI increased two-fold after 6 months of treatment and persisted thereafter, with worse scores in women. Several baseline characteristics moderated the sex differences, though none could fully account for them. These findings improve our understanding of sex differences and underscore their importance in axSpA.

Sex Differences in the Effectiveness of First-Line Tumor Necrosis Factor Inhibitors in Psoriatic Arthritis: Results From the European Spondyloarthritis Research Collaboration Network.

OBJECTIVE: Women with psoriatic arthritis (PsA) may have reduced tumor necrosis factor inhibitor (TNFi) effectiveness compared to men. We examined sex differences in treatment response and retention rates during 24 months of follow-up among patients with PsA initiating their first TNFi. METHODS: Data from patients with PsA across 13 European Spondyloarthritis Research Collaboration Network registries starting their first TNFi were pooled. Logistic regression was used to analyze the association between sex and treatment response using low disease activity (LDA) according to the Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP) (<3.2) at six months as the primary outcome. Analyses were adjusted for age, country, conventional synthetic disease-modifying antirheumatic drug treatment, and TNFi start year. Retention rates were explored using the Kaplan-Meier estimator. RESULTS: We analyzed the treatment response of 7,679 patients with PsA (50% women) with available data on LDA at six months. At baseline, women and men had similar characteristics, including mean DAS28-CRP (women vs men, 4.4 [SD 1.2] vs 4.2 [SD 1.2]), though patient-reported outcome measures were worse in women. At six months, 64% of women and 78% of men had LDA (relative risk [RR] 0.82; 95% confidence interval [CI] 0.80-0.84). This difference was similar after adjustment (RR 0.83; 95% CI 0.81-0.85). TNFi retention rates were evaluated in 17,842 patients with PsA. Women had significantly lower retention rates than men at all time points (women 79%, 64%, and 50% vs men 88%, 77%, and 64% at 6, 12, and 24 months, respectively). CONCLUSION: Despite comparable disease characteristics at baseline, women with PsA have reduced treatment response and retention rates to their first TNFi, highlighting the need to consider sex differences in PsA research and management.

18F-sodium fluoride PET-CT visualizes both axial and peripheral new bone formation in psoriatic arthritis patients.

PURPOSE: As bone formation is associated with psoriatic arthritis (PsA), positron emission tomography (PET) using a 18F-Fluoride tracer may enable sensitive detection of disease activity. Our primary aim was to determine the feasibility of whole-body 18F-sodium fluoride PET-CT in clinically active PsA patients to depict new bone formation (as a reflection of disease activity) at peripheral joints and entheses. Our secondary aim was to describe 18F-sodium fluoride findings in the axial skeleton. METHODS: Sixteen patients (female 10/16, age 50.6 ± 8.9 years) with PsA fulfilling CASPAR criteria or with a clinical diagnosis of PsA according to the treating rheumatologist and with ≥ 1 clinically active enthesitis site were included. Of each patient, a whole-body 18F-sodium fluoride PET-CT scan was performed. All scans were scored for PET-positive lesions at peripheral joints, enthesis sites and the spine. Clinical disease activity was assessed by swollen/tender joint count 44, enthesitis according to MASES and SPARCC scores. RESULTS: Out of 1088 evaluated joints, 109 joints showed PET enhancement, mainly in the interphalangeal and metatarsal joints of the feet (14/109, 12.9%) and the distal interphalangeal joints of the hands (14/109, 12.9%). PET positivity was found at 44/464 enthesis sites, mainly at the patella tendon insertion (11/44, 25%) and quadriceps tendon insertion (10/44, 22.7%). Of the PET-positive joints and enthesis sites, respectively 18.2% and 29.5% were clinically positive; 81.8% and 70.5% of the PET-positive joints and entheses respectively were clinically asymptomatic. In 11 patients, ≥ 1 axial PET-positive lesion was observed, mainly in the cervical spine. CONCLUSIONS: New molecular bone formation was observed on 18F-sodium fluoride PET-CT scans, in all domains in which PsA disease activity can be observed, with a substantial part showing no clinical symptoms. CLINICAL TRIAL REGISTRATION: EudraCT: 2017-004,850-40, registered on 13 December 2017.

Ultrasound-guided lymph node biopsy sampling to study the immunopathogenesis of rheumatoid arthritis: a well-tolerated valuable research tool.

BACKGROUND: Analyses of lymphoid organs are required to further elucidate the pathogenesis of inflammatory diseases like rheumatoid arthritis (RA). Yet, invasive tissue collection methods are scarcely applied, because they are often considered burdensome, although patients do not always consider invasive methods as a high burden. We aimed to investigate the perspectives of study participants undergoing ultrasound-guided inguinal lymph node (LN) needle biopsy sampling and determine the molecular and cellular quantity and quality of LN biopsies. METHODS: Together with patient research partners, questionnaires were developed to evaluate the motives, expectations, and experiences of participants undergoing a LN biopsy. Healthy controls and RA(-risk) patients were asked to complete these questionnaires before and after the procedure. RNA and lymphocyte yields from obtained LN biopsies were also calculated. RESULTS: We included 50 individuals, of which 43 (86%) reported their pre- and post-procedure experiences. The median reported pain on a 5-point Likert scale (1 not to 5 very painful) was 1. Interestingly, almost all (n = 32; 74%) study participants would undergo a second procedure and more than half (n = 23; 54%) would encourage others to take part in the LN biopsy study. Motives for current and future participation were mostly altruistic. Inguinal hematoma occurred frequently, but no other significant or unexpected complications ensued. The LN biopsies yielded sufficient and high-quality RNA and lymphocyte numbers. CONCLUSIONS: Ultrasound-guided inguinal LN biopsy sampling is well-tolerated, safe, and provides sufficient material for further molecular and cellular analyses. Our participants' positive experiences endorse the application of this research tool to further elucidate the pathogenesis of RA and other inflammatory diseases.

Dual Blockade of TNF and IL-17A Inhibits Inflammation and Structural Damage in a Rat Model of Spondyloarthritis.

The tumor necrosis factor (TNF) and IL-23/IL-17 axes are the main therapeutic targets in spondyloarthritis. Despite the clinical efficacy of blocking either pathway, monotherapy does not induce remission in all patients and its effect on new bone formation remains unclear. We aimed to study the effect of TNF and IL-17A dual inhibition on clinical disease and structural damage using the HLA-B27/human ß2-microglobulin transgenic rat model of SpA. Immunized rats were randomized according to arthritis severity, 1 week after arthritis incidence reached 50%, to be treated twice weekly for a period of 5 weeks with either a dual blockade therapy of an anti-TNF antibody and an anti-IL-17A antibody, a single therapy of either antibody, or PBS as vehicle control. Treatment-blinded observers assessed inflammation and structural damage clinically, histologically and by micro-CT imaging. Both single therapies as well as TNF and IL-17A dual blockade therapy reduced clinical spondylitis and peripheral arthritis effectively and similarly. Clinical improvement was confirmed for all treatments by a reduction of histological inflammation and pannus formation (p < 0.05) at the caudal spine. All treatments showed an improvement of structural changes at the axial and peripheral joints on micro-CT imaging, with a significant decrease for roughness (p < 0.05), which reflects both erosion and new bone formation, at the level of the caudal spine. The effect of dual blockade therapy on new bone formation was more prominent at the axial than the peripheral level. Collectively, our study showed that dual blockade therapy significantly reduces inflammation and structural changes, including new bone formation. However, we could not confirm a more pronounced effect of dual inhibition compared to single inhibition.

Lower Metabolic Potential and Impaired Metabolic Flexibility in Human Lymph Node Stromal Cells from Patients with Rheumatoid Arthritis.

Cellular metabolism is important for determining cell function and shaping immune responses. Studies have shown a crucial role for stromal cells in steering proper immune responses in the lymph node microenvironment. These lymph node stromal cells (LNSCs) tightly regulate immune tolerance. We hypothesize that malfunctioning LNSCs create a microenvironment in which normal immune responses are not properly controlled, possibly leading to the development of autoimmune diseases such as rheumatoid arthritis (RA). Therefore, we set out to determine their metabolic profile during health and systemic autoimmunity. We included autoantibody positive individuals at risk of developing RA (RA-risk individuals), RA patients and healthy volunteers. All study subjects underwent lymph node biopsy sampling. Mitochondrial function in cultured LNSCs was assessed by quantitative PCR, flow cytometry, Seahorse and oleate oxidation assays. Overall, mitochondrial respiration was lower in RA(-risk) LNSCs compared with healthy LNSCs, while metabolic potential was only lower in RA LNSCs. To maintain basal mitochondrial respiration, all LNSCs were mostly dependent on fatty acid oxidation. However, RA(-risk) LNSCs were also dependent on glutamine oxidation. Finally, we showed that RA LNSCs have impaired metabolic flexibility. Our results show that the metabolic landscape of LNSCs is not only altered during established disease, but partly already in individuals at risk of developing RA. Future studies are needed to investigate the impact of restoring metabolic capacity in LNSC-mediated immunomodulation and disease progression.

European bio-naïve spondyloarthritis patients initiating TNF inhibitor: time trends in baseline characteristics, treatment retention and response.

OBJECTIVES: To investigate time trends in baseline characteristics and retention, remission and response rates in bio-naïve axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) patients initiating TNF inhibitor (TNFi) treatment. METHODS: Prospectively collected data on bio-naïve axSpA and PsA patients from routine care in 15 European countries were pooled. Three cohorts were defined according to year of TNFi initiation: A (1999-2008), B (2009-2014) and C (2015-2018). Retention, remission and response rates were assessed at 6, 12 and 24 months. RESULTS: In total, 27 149 axSpA and 17 446 PsA patients were included. Cohort A patients had longer disease duration compared with B and C. In axSpA, cohort A had the largest proportion of male and HLA-B27 positive patients. In PsA, baseline disease activity was highest in cohort A. Retention rates in axSpA/PsA were highest in cohort A and differed only slightly between B and C. For all cohorts, disease activity decreased markedly from 0 to 6 months. In axSpA, disease activity at 24 months was highest in cohort A, where also remission and response rates were lowest. In PsA, remission rates at 6 and 12 months tended to be lowest in cohort A. Response rates were at all time points comparable across cohorts, and less between-cohort disease activity differences were seen at 24 months. CONCLUSION: Our findings indicate that over the past decades, clinicians have implemented more aggressive treatment strategies in spondyloarthritis. This was illustrated by shorter disease duration at treatment initiation, decreased retention rates and higher remission rates during recent years.

The Role of the IL-23/IL-17 Axis in Disease Initiation in Spondyloarthritis: Lessons Learned From Animal Models.

Spondyloarthritis (SpA) is a spectrum of chronic inflammatory joint diseases that frequently presents with inflammation of the axial skeleton, peripheral joints, entheses, skin, and gut. Understanding SpA pathogenesis has been proven challenging due to the limited availability of human target tissues. In recent years, the interleukin (IL)-23/IL-17 pathway has been implicated in the pathogenesis of SpA, in addition to the Tumor Necrosis Factor Alpha (TNF-α) cytokine. The underlying molecular mechanisms by which the IL-23/IL-17 pathway triggers disease initiation, both in the joints as well as at extra-musculoskeletal sites, are not precisely known. Animal models that resemble pathological features of human SpA have provided possibilities for in-depth molecular analyses of target tissues during various phases of the disease, including the pre-clinical initiation phase of the disease before arthritis and spondylitis are clinically present. Herein, we summarize recent insights gained in SpA animal models on the role of the IL-23/IL-17 pathway in immune activation across affected sites in SpA, which include the joint, entheses, gut and skin. We discuss how local activation of the IL-23/IL-17 axis may contribute to the development of tissue inflammation and the onset of clinically manifest SpA. The overall aim is to provide the reader with an overview of how the IL-23/IL-17 axis could contribute to the onset of SpA pathogenesis. We discuss how insights from animal studies into the initiation phase of disease could instruct validation studies in at-risk individuals and thereby provide a perspective for potential future preventive treatment.

Novel Insights Into Rheumatoid Arthritis Through Characterization of Concordant Changes in DNA Methylation and Gene Expression in Synovial Biopsies of Patients With Differing Numbers of Swollen Joints.

In this study, we sought to characterize synovial tissue obtained from individuals with arthralgia and disease-specific auto-antibodies and patients with established rheumatoid arthritis (RA), by applying an integrative multi-omics approach where we investigated differences at the level of DNA methylation and gene expression in relation to disease pathogenesis. We performed concurrent whole-genome bisulphite sequencing and RNA-Sequencing on synovial tissue obtained from the knee and ankle from 4 auto-antibody positive arthralgia patients and thirteen RA patients. Through multi-omics factor analysis we observed that the latent factor explaining the variance in gene expression and DNA methylation was associated with Swollen Joint Count 66 (SJC66), with patients with SJC66 of 9 or more displaying separation from the rest. Interrogating these observed differences revealed activation of the immune response as well as dysregulation of cell adhesion pathways at the level of both DNA methylation and gene expression. We observed differences for 59 genes in particular at the level of both transcript expression and DNA methylation. Our results highlight the utility of genome-wide multi-omics profiling of synovial samples for improved understanding of changes associated with disease spread in arthralgia and RA patients, and point to novel candidate targets for the treatment of the disease.

IL-12p40/IL-23p40 Blockade With Ustekinumab Decreases the Synovial Inflammatory Infiltrate Through Modulation of Multiple Signaling Pathways Including MAPK-ERK and Wnt.

Background: Psoriatic arthritis (PsA) is a chronic inflammatory joint disease within the spondyloarthritis spectrum. IL-12p40/IL-23p40 blockade reduces PsA disease activity, but its impact on synovial inflammation remains unclear. Objectives: To investigate the cellular and molecular pathways affected by IL-12p40/IL-23p40 blockade with ustekinumab in the synovium of PsA patients. Methods: Eleven PsA patients with at least one inflamed knee or ankle joint were included in a 24-week single-center open-label study and received ustekinumab 45 mg/sc according to standard care at week 0, 4, and 16. Besides clinical outcomes, synovial tissue (ST) samples were obtained by needle arthroscopy from an inflamed knee or ankle joint at baseline, week 12 and 24 and analyzed by immunohistochemistry, RNA-sequencing and real-time quantitative polymerase chain reaction (qPCR). Results: We obtained paired baseline and week 12, and paired baseline, week 12 and 24 ST samples from nine and six patients, respectively. Eight patients completed 24 weeks of clinical follow-up. At 12 weeks 6/11 patients met ACR20, 2/11 met ACR50 and 1/11 met ACR70 improvement criteria, at 24 weeks this was 3/8, 2/8 and 1/8 patients, respectively. Clinical and serological markers improved significantly. No serious adverse events occurred. We observed numerical decreases of all infiltrating cell subtypes at week 12, reaching statistical significance for CD68+ sublining macrophages. For some cell types this was even more pronounced at week 24, but clearly synovial inflammation was incompletely resolved. IL-17A and F, TNF, IL-6, IL-8, and IL-12p40 were not significantly downregulated in qPCR analysis of W12 total biopsies, only MMP3 and IL-23p19 were significantly decreased. RNA-seq analysis revealed 178 significantly differentially expressed genes between baseline and 12 weeks (FDR 0.1). Gene Ontology and KEGG terms enrichment analyses identified overrepresentation of biological processes as response to reactive oxygen species, chemotaxis, migration and angiogenesis as well as MAPK-ERK and PI3K-Akt signaling pathways among the downregulated genes and of Wnt signaling pathway among the upregulated genes. Furthermore, ACR20 responders and non-responders differed strikingly in gene expression profiles in a post-hoc exploratory analysis. Conclusions: Ustekinumab suppresses PsA synovial inflammation through modulation of multiple signal transduction pathways, including MAPK-ERK, Wnt and potentially PI3K-Akt signaling rather than by directly impacting the IL-17 pathway.

Anti-IL-17A treatment reduces serum inflammatory, angiogenic and tissue remodeling biomarkers accompanied by less synovial high endothelial venules in peripheral spondyloarthritis.

Spondyloarthritis (SpA) is characterized by inflammation and new bone formation. The exact pathophysiology underlying these processes remains elusive. We propose that the extensive neoangiogenesis in SpA could play a role both in sustaining/enhancing inflammation and in new bone formation. While ample data is available on effects of anti-TNF on angiogenesis, effects of IL-17A blockade on serum markers are largely unknown. We aimed to assess the impact of secukinumab (anti-IL-17A) on synovial neoangiogenesis in peripheral SpA, and how this related to changes in inflammatory and tissue remodeling biomarkers. Serum samples from 20 active peripheral SpA patients included in a 12 week open-label trial with secukinumab were analyzed for several markers of angiogenesis and tissue remodeling. Synovial biopsies taken before and after treatment were stained for vascular markers. Serum levels of MMP-3, osteopontin, IL-6 (all P < 0.001), IL-31, S100A8, S100A9, Vascular Endothelial Growth Factor A (VEGF-A), IL-33, TNF-α (all P < 0.05) decreased significantly upon anti-IL17A treatment. Secukinumab treatment resulted in a decrease in the number of synovial high endothelial venules and lymphoid aggregate score. These results indicate that anti-IL-17A not only diminishes inflammation, but also impacts angiogenesis and tissue remodeling/new bone formation. This may have important implications for disease progression and/or structural damage.

Interleukin 17A and IL-17F Expression and Functional Responses in Rheumatoid Arthritis and Peripheral Spondyloarthritis.

OBJECTIVE: Targeting the interleukin 17 (IL-17) axis is efficacious in psoriasis and spondyloarthritis (SpA), but not in rheumatoid arthritis (RA). We investigated potential differences in tissue expression and function of IL-17A and IL-17F in these conditions. METHODS: mRNA expression of cytokines and their receptors was assessed by quantitative PCR in psoriasis skin samples, in SpA and RA synovial tissue (ST) samples and in fibroblast-like synoviocytes (FLS). Cytokines were measured in synovial fluid (SF) and FLS supernatants by ELISA. FLS were stimulated with IL-17A or IL-17F cytokines supplemented with tumor necrosis factor (TNF), or with pooled SF from patients with SpA or RA. RESULTS: Levels of IL-17A (P = 0.031) and IL-17F (P = 0.017) mRNA were lower in psoriatic arthritis ST compared to paired psoriasis skin samples. The level of IL-17A mRNA was 2.7-fold lower than that of IL-17F in skin (P = 0.0078), but 17.3-fold higher in ST (P < 0.0001). In SF, the level of IL-17A protein was 37.4-fold higher than that of IL-17F [median 292.4 (IQR 81.4-464.2) vs median 7.8 (IQR 7.7-8.7) pg/mL; P < 0.0001]. IL-17A and IL-17F mRNA and protein levels did not differ in SpA compared to RA synovitis samples, and neither were the IL-17 receptors IL-17RA and IL-17RC, or the TNF receptors TNFR1 and TNR2, differentially expressed between SpA and RA ST, nor between SpA and RA FLS. SpA and RA FLS produced similar amounts of IL-6 and IL-8 protein upon stimulation with IL-17A or IL-17F cytokines, supplemented with 1 ng/ml TNF. Pooled SpA or RA SF samples similarly enhanced the inflammatory response to IL-17A and IL-17F simulation in FLS. CONCLUSION: The IL-17A/IL-17F expression ratio is higher in SpA synovitis compared to psoriasis skin. Expression of IL-17A and IL-17F, and the functional response to these cytokines, appear to be similar in SpA and RA synovitis.

Sustained remission with methotrexate monotherapy after 22-week induction treatment with TNF-alpha inhibitor and methotrexate in early psoriatic arthritis: an open-label extension of a randomized placebo-controlled trial.

BACKGROUND: If TNF inhibitors are initiated in the early stages of psoriatic arthritis, this could potentially modulate disease and therefore allow us to discontinue the TNF inhibitor after achieving remission. OBJECTIVE: To investigate whether remission induced by tumour necrosis factor alpha inhibitor (TNFi) and methotrexate in patients with early psoriatic arthritis is sustained after withdrawal of TNFi. METHODS: Open-label extension of a recently published double-blind, randomized placebo-controlled trial. Patients with psoriatic arthritis fulfilling the CASPAR criteria and with active disease at baseline (swollen and tender joint count ≥ 3) were randomized to either golimumab and methotrexate or matched placebo and methotrexate. Patients in Disease Activity Score (DAS) remission at week 22 continued in the open-label extension on methotrexate monotherapy. The primary end point was the percentage of patients in DAS-CRP remission (DAS < 1.6) at week 50. RESULTS: Eight patients from the original placebo group and 18 patients from the original TNFi group continued in the extension phase. At week 50, 6 out of 8 (75%) patients from the original MTX (methotrexate) group versus 10 out of 18 (56%) patients from the original MTX+TNFi group were in DAS-CRP remission (p = 0.347). Considering the total study population, 6 out of 24 (25%) of the original MTX group versus 10 out of 26 (38.5%) of the original MTX+TNFi group were in DAS remission at week 50 (p = 0.308). CONCLUSIONS: Remission achieved by initial combination treatment with TNFi and methotrexate in early psoriatic arthritis is maintained on methotrexate monotherapy in approximately half of the patients. TRIAL REGISTRATION: Registered at Clinicaltrials.gov with number NCT01871649 on June 7, 2013.

Achieving remission in psoriatic arthritis by early initiation of TNF inhibition: a double-blind, randomised, placebo-controlled trial of golimumab plus methotrexate versus placebo plus methotrexate.

OBJECTIVES: Early initiation of effective treatment favours remission in rheumatoid arthritis, but it remains unknown if the same concept applies to psoriatic arthritis (PsA). Therefore, this study investigated whether the combination of golimumab plus methotrexate (MTX) as a first-line treatment is superior to MTX alone in inducing remission in PsA. METHODS: This investigator-initiated, multicentre, double-blind, randomised, placebo-controlled trial included 51 MTX and bDMARD-naive patients with PsA fulfilling the CASPAR criteria and with active disease at baseline (≥3 swollen joint count/tender joint count). Patients were randomised to golimumab (50 mg SC monthly)+MTX (n=26) (TNFi arm) or matched placebo+MTX (n=25) (MTX arm). MTX was started 15 mg/week and increased to 25 mg/week over 8 weeks. The primary endpoint was percentage of patients achieving Disease Activity Score (DAS) remission (<1.6) at week 22. Safety was assessed throughout the study. RESULTS: The primary efficacy endpoint was achieved by 81% in the TNFi arm versus 42 % in the MTX arm (p=0.004). This difference in DAS remission was already observed at week 8. A significant difference in favour of the golimumab+MTX arm at week 22 was also observed for other response criteria such as MDA, ACR20/50/70, disease measures and patient-reported outcomes. The occurrence rates of adverse event and treatment-emergent adverse event were similar in both arms. CONCLUSIONS: In patients with early PsA, DAS remission at week 22 was almost doubled with golimumab+MTX versus MTX alone. This double-blind, randomised, placebo-controlled study supports the concept that early initiation of TNFi in patients with PsA favours remission. TRIAL REGISTRATION NUMBER: NCT01871649.

Interleukin-17A Inhibition Diminishes Inflammation and New Bone Formation in Experimental Spondyloarthritis.

OBJECTIVE: It remains unclear if and how inflammation and new bone formation in spondyloarthritis (SpA) are coupled. We undertook this study to assess the hypothesis that interleukin-17A (IL-17A) is a pivotal driver of both processes. METHODS: The effect of tumor necrosis factor (TNF) and IL-17A on osteogenesis was tested in an osteoblastic differentiation assay using SpA fibroblast-like synoviocytes (FLS) differentiated with dexamethasone, ß-glycophosphatase, and ascorbic acid. IL-17A blockade was performed in HLA-B27/human ß2 -microglobulin (hß2 m)-transgenic rats, which served as a model for SpA in both prophylactic and therapeutic settings. Inflammation and new bone formation were evaluated by micro-computed tomography imaging, histologic analysis, and gene expression profiling. RESULTS: TNF and IL-17A significantly increased in vitro osteoblastic differentiation. In vivo, prophylactic blockade of IL-17A significantly delayed spondylitis and arthritis development and decreased arthritis severity. Anti-IL-17A treatment was also associated with prevention of bone loss and periosteal new bone formation. Therapeutic targeting of IL-17A after the initial inflammatory insult also significantly reduced axial and peripheral joint inflammation. This treatment was again associated with a marked reduction in spinal and peripheral structural damage, including new bone formation. RNA sequencing of target tissue confirmed that IL-17A is a key driver of the molecular signature of disease in this model and that therapeutic anti-IL-17A treatment reversed the inflammatory signature and the selected gene expression related to bone damage. CONCLUSION: Both prophylactic and therapeutic inhibition of IL-17A diminished inflammation and new bone formation in HLA-B27/hß2 m-transgenic rats. Taken together with the ability of IL-17A to promote osteoblastic differentiation of human SpA FLS, these data suggest a direct link between IL-17A-driven inflammation and pathologic new bone formation in SpA.

Expansion of Interleukin-22- and Granulocyte-Macrophage Colony-Stimulating Factor-Expressing, but Not Interleukin-17A-Expressing, Group 3 Innate Lymphoid Cells in the Inflamed Joints of Patients With Spondyloarthritis.

OBJECTIVE: Clinical trials of the anti-interleukin-17A (anti-IL-17A) antibody secukinumab have demonstrated a crucial role of the cytokine IL-17A in the pathogenesis of spondyloarthritis (SpA); however, its cellular source in this condition remains a matter of controversy. Group 3 innate lymphoid cells (ILC3s) have been recently identified as potent producers of proinflammatory cytokines, including IL-17A and IL-22, in a number of different tissues. This study was undertaken to characterize the presence and composition of ILCs, and investigate whether these cells are an important source of IL-17A, in the synovial tissue (ST) of patients with SpA. METHODS: Matched ST, synovial fluid, and peripheral blood (PB) samples were obtained from SpA patients with actively inflamed knee joints. ILC subsets were characterized by flow cytometry. Gene expression analysis at the single-cell level was performed directly ex vivo and after in vitro activation. An IL-17A enzyme-linked immunospot assay was used to detect IL-17A-secreting cells. RESULTS: ILCs, and particularly NKp44+ ILC3s, were expanded in inflamed arthritic joints. Single-cell expression analysis demonstrated that ST ILCs were clearly distinguishable from ST T cells and from their PB counterparts. Expression of the Th17 signature transcripts RORC, AHR, and IL23R was detected in a large proportion of ST ILC3s. These cells were capable of inducing expression of IL22 and CSF2, but not IL17A, in response to in vitro restimulation. CONCLUSION: Our findings demonstrate that absolute and relative numbers of ILC3s are enriched in the synovial joints of patients with SpA. However, these cells are not a significant source of IL-17A in this disease.

Brief Report: Interleukin-17 Blockade With Secukinumab in Peripheral Spondyloarthritis Impacts Synovial Immunopathology Without Compromising Systemic Immune Responses.

OBJECTIVE: Secukinumab (anti-interleukin-17A [anti-IL-17A]) is an effective therapy for ankylosing spondylitis and psoriatic arthritis, the prototypical forms of spondyloarthritis (SpA). We undertook this study to determine whether secukinumab modulates the immunopathology of target lesions without blunting systemic immune responses, using peripheral SpA as a model. METHODS: Twenty patients with active peripheral SpA were included in a 12-week open-label trial with secukinumab (300 mg once weekly from baseline to week 4 and then every 4 weeks thereafter). Outcomes included clinical response, cytokine production by peripheral blood cells using TruCulture technology, and histologic and real-time quantitative polymerase chain reaction analysis of synovial biopsy samples before and after treatment. RESULTS: All patients completed the 12-week study without severe adverse events (AEs) or severe treatment-related AEs. The efficacy end point, the number of patients meeting the American College of Rheumatology 20% improvement criteria (achieving an ACR20 response) at 12 weeks, was achieved by 13 of the 20 patients, of whom 8 achieved an ACR50 response and 5 achieved an ACR70 response, with rapid and significant improvements in all clinical disease activity measures. Clinical improvement in joint counts was associated with a histologic decrease in synovial sublining macrophages (P = 0.028) and neutrophils (P = 0.004), both of which are sensitive synovial biomarkers of inflammatory response in peripheral SpA, as well as with decreased synovial expression of IL-17A messenger RNA (mRNA) (P = 0.010) but not of tumor necrosis factor mRNA. Systemically, secukinumab treatment decreased the C-reactive protein level and the erythrocyte sedimentation rate (both P < 0.01), and also decreased matrix metalloproteinase 3 production in the TruCulture system (P < 0.05). However, with the exception of IL-17A itself, the capacity of peripheral blood cells to produce a broad panel of cytokines and chemokines upon stimulation with microbial antigens was not affected. CONCLUSION: This mechanism-of-action study in peripheral SpA indicates that clinical improvement with secukinumab treatment is paralleled by immunomodulation of inflamed target tissues without compromising systemic immune responses.

Residual disease activity in psoriatic arthritis: discordance between the rheumatologist's opinion and minimal disease activity measurement.

Objective: To assess how many PsA patients with an acceptable disease state according to the treating rheumatologist have quiescent disease defined as minimal disease activity (MDA). Methods: This cross-sectional study included 250 PsA patients. To assess current clinical practice as closely as possible, acceptable disease state was not determined by predefined activity measures, but instead was defined by asking rheumatologists to refer those patients whom they considered sufficiently treated. Patients were evaluated for current disease activity including clinical assessments and patient reported outcomes (PROs). Results: One-third (88/250) of the patients with acceptable disease state according to the rheumatologist did not fulfil MDA (MDA-). The presence of tender joints and patient pain and global disease activity scores most frequently contributed to not fulfilling MDA (not achieved in 83, 82 and 80%, respectively). However, also objective signs of disease activity were higher in the MDA- than MDA+ patient group: a swollen joint count >1 occurred in 35% vs 7% (P < 0.001), enthesitis >1 in 14% vs 3% (P = 0.002) and Psoriasis Area and Severity Index >1 in 43% vs 26% (P = 0.002). Residual disease was more frequent in females, elder patients and those with a raised BMI, independent of the treatment schedule, and negatively influenced PROs of function and quality of life. Conclusion: One-third of the PsA patients with acceptable disease state according to the treating rheumatologist did not fulfil the MDA criteria and had residual disease activity on both subjective and objective disease activity measurements. As residual disease activity was associated with worse PROs, future strategy trials should evaluate if treatment adjustments are beneficial for this patient group.

Ideal target for psoriatic arthritis? Comparison of remission and low disease activity states in a real-life cohort.

BACKGROUND: Psoriatic arthritis (PsA) recommendations state that the target of treatment should be remission or low disease activity (LDA). We used a real-life dataset to compare different potential targets. METHODS: 250 patients with PsA considered in an acceptable disease state according to their rheumatologist were included. Targets for remission were the Disease Activity Index for Psoriatic Arthritis (DAPSA) and clinical DAPSA (cDAPSA) remission (≤4), very low disease activity (VLDA) and Psoriatic Arthritis Disease Activity Score ≤1.9. LDA targets analysed were the DAPSA ≤14, cDAPSA ≤13, minimal disease activity (MDA) and adjusted MDA targets: MDAjoints with both tender joint count (TJC) and swollen joint count (SJC) mandated, MDAskin (psoriasis area and severity index (PASI) mandated) and MDAjoints&skin with TJC, SJC and PASI mandated. RESULTS: Comparison of the several candidate targets demonstrates that VLDA is achieved by the lowest proportion of patients and includes patients with the lowest residual disease activity compared with the other remission targets. The modified MDA measures are the most stringent targets for LDA in terms of residual disease on joints, psoriasis and enthesitis within patients achieving the target. In both remission and LDA, the inclusion of C reactive protein did not show an added value. The exclusion of a skin domain, as in the DAPSA measures, resulted in negligence of skin disease and a negative impact on the quality of life in some patients. CONCLUSIONS: The different remission and LDA targets show us significant overlap between measures, but these measures targeting the same definition do differ in terms of allowance of residual disease. Inclusion of laboratory markers seems unnecessary, although exclusion of a skin domain may result in psoriasis not being assessed resulting in residual impactful skin disease.