High prevalence of radiographic erosions in early, untreated PsA: results from the SpARRO cohort.

AIMS: To investigate the prevalence and distribution of bone erosions in an early psoriatic arthritis (PsA) population using conventional radiography (CR) and to explore the agreement between CR and ultrasound (US) detected bone erosions. METHODS: Newly diagnosed, treatment naïve PsA patients fulfilling the ClASsification for Psoriatic Arthritis (CASPAR) classification criteria of ≤5 years symptom duration were recruited as part of the Leeds Spondyloarthropathy Register for Research and Observation and underwent CR and US examination of hands and feet. RESULTS: Overall, 4655 hand and feet joints were assessed in 122 patients. CR erosions were detected in 24.6% (n=30) with lowest prevalence seen below 8 months of symptoms (17.5% vs 24.3%>24 months). The number of erosions was higher on CR (1.55% (63/4,655); US 1.04% (34/3,270)), with 5th metatarsophalangeal (MTP) joint being the most affected site in both CR (5.21% (11/211)) and US (7.14% (15/210)). Erosions in CR were more evenly distributed compared with US where three-quarters of the total number of bone erosions were detected in wrists, second metacarpophalangeal (MCP) and fifth MTP joints. Most joints had almost perfect prevalence-adjusted bias-adjusted kappa values ranging from 0.91 to 1. CONCLUSIONS: Erosions were seen in a quarter of patients with newly diagnosed, untreated PsA with a declining trend around the 8-month symptom duration cut-off. High levels of agreement between CR and US were seen with CR detecting more erosions. A focused US assessment of the wrist, second MCP and fifth MTP joints may be useful to detect bone erosions in early PsA.

Association of circulating lymphocyte subsets with response to IL17i and TNFi in axial spondyloarthritis.

OBJECTIVES: Biologic disease-modifying anti-rheumatic drugs (b-DMARDs) have qualitatively improved the management of axial spondyloarthritis (axSpA), but up to 30-40% of patients do not respond. Although lymphocytes are clearly implicated in the pathology of SpA, circulating lymphocyte subsets (LS) dynamics has been poorly studied. The objective of this pilot study was to comprehensively analyse circulating LS abnormalities in axSpA, and to determine their potential association with response to b-DMARDs. METHODS: Sixty-nine patients with axSpA and 141 control subjects (HC) were included. The clinical features were measured at baseline, and additionally at 6 months in a subgroup of patients who received TNFi (n=36) or IL17i (n=26). Clinical response was defined as a 50% reduction of BASDAI or decrease in ASDAS of 1.1 point. CD4/CD8 T-cells, B-cells and NK-cells and their subsets were analysed by flow cytometry at inclusion. RESULTS: At baseline, alterations in LS were observed in axSpA with reduced/increased frequencies of 10/27 subsets (p<0.003 after correction) and trends for another 5. There was no association of response to bDMARDs with clinical data. Response to IL17i (61% cases) was associated with a higher frequency of NK-cells (p=0.003), trends for change in naïve/memory-CD8+T-cells (p<0.055) and increased expression of KIR3DL2 on Th17-cells (p=0.052). No LS was associated with response to TNFi (69% cases) although trends were observed (CD4+T-cells subsets, higher IL-6R on CD4+/CD8+T-cells). CONCLUSIONS: This pilot work demonstrated a dysregulation of LS in axSpA. The association observed between several LS and clinical response to IL17i (NK/CD8 subsets/Th17-KIR3DL2) was very different to that observed for TNFi (CD4/IL-6R).

Ultrasound shows swollen joints are the better proxy for synovitis than tender joints in DMARD-naïve early psoriatic arthritis.

Objective: To evaluate the relationship between clinical examination/US synovitis in DMARD-naïve early PsA. Methods: Eligible patients underwent matched clinical/US 44-joint assessment for tender and/or swollen joints (TJ/SJ) and US synovitis [grey scale (GS) ≥ 2 or power Doppler (PD) ≥ 1]. Statistical agreement between TJ/SJ, GS ≥ 2 and PD ≥ 1 was calculated by prevalence-adjusted and bias-adjusted κ (PABAK). To derive probabilities of GS ≥ 2/PD ≥ 1, mixed-effects logistic regression-modelled odds of US synovitis in TJ/SJ were conducted. Results: In 155 patients, 5616 joints underwent clinical/US examination. Of these joints, 1039 of 5616 (18.5%) were tender, 550 of 5616 (9.8%) were swollen, 1144 of 5616 (20.4%) had GS ≥ 2, and 292 of 5616 (5.2%) had PD ≥ 1. GS ≥ 2 was most prevalent in concomitantly tender and swollen joints [205 of 462 (44%)], followed by swollen non-tender joints [32 of 88 (36.4%)], tender non-swollen joints [148 of 577 (25.7%)] and non-tender non-swollen joints (subclinical synovitis) [759 of 4489 (16.9%)]. Agreement between SJ/PD ≥ 1 was high at the individual joint level (82.6-96.3%, PABAK 0.65-0.93) and for total joints combined (89.9%, PABAK 0.80). SJ/GS ≥ 2 agreement was greater than between TJ/GS ≥ 2 [73.5-92.6% vs 51.0-87.4% (PABAK 0.47-0.85 vs PABAK 0.35-0.75), respectively]. Swelling was independently associated with higher odds of GS ≥ 2 [odds ratio (OR) (95% CI); 4.37 (2.62, 7.29); P < 0.001] but not tenderness [OR = 1.33 (0.87, 2.06); P = 0.192]. Swelling [OR = 8.78 (3.92, 19.66); P < 0.001] or tenderness [OR = 3.38 (1.53, 7.50); P = 0.003] was independently associated with higher odds of PD ≥ 1. Conclusion: Synovitis (GS ≥ 2 and/or PD ≥ 1) was more likely in swollen joints than in tender joints in DMARD-naïve, early PsA. Agreement indicated that swollen joints were the better proxy for synovitis, adding to greater understanding between clinical and US assessments.

Ultrasound Imaging in Psoriatic Arthritis: What Have We Learnt in the Last Five Years?

Psoriatic arthritis (PsA) is a complex heterogeneous disease with multiple inter-related pathologies such as synovitis, enthesitis, tendinopathy, and dactylitis. Clinical assessment is limited in its detail to assess pathology, thus in recent years, ultrasound (US) has become more popular, given its high sensitivity to detect inflammatory arthritis and ability to inform clinical decisions. Although a qualitative technique, US findings can be graded semi-quantitatively for grayscale (GS) and power Doppler (PD). Synovitis is frequently present in inflammatory arthritis pathologies, and in PsA, recent evidence shows a propensity for tendon and entheseal lesions. The presence of flexor tenosynovitis and flexor tendon insertional enthesopathy at accessory pulleys is supportive of the "Deep Koebner" concept. Peri-tendinous inflammation-mutual to PsA or rheumatoid arthritis (RA), is associated with soft tissue oedema with PD signal frequently at the flexor tendon compartments in PsA. Research on enthesitis in PsA/PsO has improved understanding in subclinical and clinical PsA, explored associations with progression to PsA, and investigated links to prognosis assessment. Dactylitis is a pathognomonic PsA lesion where US has enhanced knowledge of the disease course and pathology of lesions such as: flexor tenosynovitis; synovitis; and soft tissue oedema. Increased US sensitivity has also brought innovation including promising automated ultrasound scanning techniques. So, what have we learnt in recent years and what are the unmet needs to focus future research initiatives in this disabling disease? This narrative review article assesses the neoteric evidence, bringing into context the knowledge gained and highlighting potential areas of research.