Power Doppler signal at the enthesis and bone erosions are the most discriminative OMERACT ultrasound lesions for SpA: results from the DEUS (Defining Enthesitis on Ultrasound in Spondyloarthritis) multicentre study.

OBJECTIVES: To assess, in spondyloarthritis (SpA), the discriminative value of the Outcome Measures in Rheumatology (OMERACT) ultrasound lesions of enthesitis and their associations with clinical features in this population. METHODS: In this multicentre study involving 20 rheumatology centres, clinical and ultrasound examinations of the lower limb large entheses were performed in 413 patients with SpA (axial SpA and psoriatic arthritis) and 282 disease controls (osteoarthritis and fibromyalgia). 'Active enthesitis' was defined as (1) power Doppler (PD) at the enthesis grade ≥1 plus entheseal thickening and/or hypoechoic areas, or (2) PD grade >1 (independent of the presence of entheseal thickening and/or hypoechoic areas). RESULTS: In the univariate analysis, all OMERACT lesions except enthesophytes/calcifications showed a significant association with SpA. PD (OR=8.77, 95% CI 4.40 to 19.20, p<0.001) and bone erosions (OR=4.75, 95% CI 2.43 to 10.10, p<0.001) retained this association in the multivariate analysis. Among the lower limb entheses, only the Achilles tendon was significantly associated with SpA (OR=1.93, 95% CI 1.30 to 2.88, p<0.001) in the multivariate analyses. Active enthesitis showed a significant association with SpA (OR=9.20, 95% CI 4.21 to 23.20, p<0.001), and unlike the individual OMERACT ultrasound lesions it was consistently associated with most clinical measures of SpA disease activity and severity in the regression analyses. CONCLUSIONS: This large multicentre study assessed the value of different ultrasound findings of enthesitis in SpA, identifying the most discriminative ultrasound lesions and entheseal sites for SpA. Ultrasound could differentiate between SpA-related enthesitis and other forms of entheseal pathology (ie, mechanical enthesitis), thus improving the assessment of entheseal involvement in SpA.

Can ultrasound help to overcome uncertainty in clinical joint assessment in juvenile idiopathic arthritis?

OBJECTIVES: Assessment of active synovitis is crucial for the management of juvenile idiopathic arthritis (JIA). We aimed to investigate the correlation of musculoskeletal ultrasound (MSUS) and clinical examination results and relate them to arthritis relapse rate. METHODS: JIA patients with questionable presence of active arthritis (Q-joints) and controls (JIA and healthy children) were recruited. MSUS of Q-joints, active joints and their inactive counterparts was performed at study entry. Standard disease activity parameters were prospectively recorded. RESULTS: Of 481 joints of 138 JIA patients, 99 joints (20.6%) of 58 patients had one or more Q-joints with 54/99 (54.5%) having MSUS features of active disease. Clinically inactive joints had lower proportion of MSUS synovitis (78/253, 30.8%) while MSUS activity was present in 114/129 (88.4%) of clinically active joints and in 2/105 (1.9%) joints of 36 healthy controls. Within the 15-month follow-up 23/99 (22%) Q-joints and 31/253 (12%) clinically inactive joints relapsed. Joints with subclinical synovitis relapsed more frequently than MSUS inactive ones (p<0.001). The relapse rate was higher in MSUS-active Q-joints (19/23, 82%) than in clinically inactive ones (16/31, 52%) with MSUS synovial hypertrophy as the main relapse predictor in multivariate analysis. Ankle and knee joints relapsed most frequently. CONCLUSIONS: Acknowledgement of joints with questionable synovitis may contribute to the assessment of disease activity in JIA. Presence of MSUS synovitis carries a clinically meaningful risk of disease recurrence in these joints. In clinical practice, our findings encourage timely MSUS assessment of the joints in question, especially in patients without any other features of active disease.

Reliability assessment of the definition of ultrasound enthesitis in SpA: results of a large, multicentre, international, web-based study.

OBJECTIVES: To investigate the reliability of the OMERACT US Task Force definition of US enthesitis in SpA. METHODS: In this web exercise, based on the evaluation of 101 images and 39 clips of the main entheses of the lower limbs, the elementary components included in the OMERACT definition of US enthesitis in SpA (hypoechoic areas, entheseal thickening, power Doppler signal at the enthesis, enthesophytes/calcifications, bone erosions) were assessed by 47 rheumatologists from 37 rheumatology centres in 15 countries. Inter- and intra-observer reliability of the US components of enthesitis was calculated using Light's kappa, Cohen's kappa, Prevalence And Bias Adjusted Kappa (PABAK) and their 95% CIs. RESULTS: Bone erosions and power Doppler signal at the enthesis showed the highest overall inter-reliability [Light's kappa: 0.77 (0.76-0.78), 0.72 (0.71-0.73), respectively; PABAK: 0.86 (0.86-0.87), 0.73 (0.73-0.74), respectively], followed by enthesophytes/calcifications [Light's kappa: 0.65 (0.64-0.65), PABAK: 0.67 (0.67-0.68)]. This was moderate for entheseal thickening [Light's kappa: 0.41 (0.41-0.42), PABAK: 0.41 (0.40-0.42)], and fair for hypoechoic areas [Light's kappa: 0.37 (0.36-0.38); PABAK: 0.37 (0.37-0.38)]. A similar trend was observed in the intra-reliability exercise, although this was characterized by an overall higher degree of reliability for all US elementary components compared with the inter-observer evaluation. CONCLUSIONS: The results of this multicentre, international, web-based study show a good reliability of the OMERACT US definition of bone erosions, power Doppler signal at the enthesis and enthesophytes/calcifications. The low reliability of entheseal thickening and hypoechoic areas raises questions about the opportunity to revise the definition of these two major components for the US diagnosis of enthesitis.

Prevalence and distribution of cartilage and bone damage at metacarpal head in healthy subjects.

OBJECTIVES: To determine the prevalence and distribution of the ultrasound (US) findings indicating cartilage and bone damage at the metacarpal head (MH) in a group of healthy subjects (HS), and their association with the clinical and US data. We also aimed to provide standard reference values of cartilage thickness. METHODS: US scans of the dorsal aspect of the metacarpophalangeal joints (MCPj) from 2nd to 5th finger of both hands were performed in 179 HS. The presence of cartilage damage, osteophytes and bone erosions was recorded. RESULTS: Cartilage damage, osteophytes and bone erosions were found in at least one MCPj in 30 (16.8%), 17 (9.5%) and 4 (2.2%) out of 179 HS, respectively. Signs of cartilage damage were found in 91 out of 1432 MHs (6.4%). Blurring of the chondrosynovial margin, minimal and severe thinning were detected in 73.7%, 26.3% and 0% of the 91 MHs, respectively. Osteophytes and bone erosions were found in 31 (2.2%) and in 4 (0.3%) MCPjs. The thickness of the MH cartilage ranged between 0.41 and 1.10 mm in males and between 0.36 and 1.03 mm in females. A significant association was found between cartilage thickness and age (r=-0.33, p<0.001), sex (rpb=0.42, p<0.001), height (r=0.39, p<0.001) and osteophytes in the same joint (v=-0.54, p<0.001) and between working condition and osteophytes (v=0.31, p=0.021). CONCLUSIONS: This cross-sectional study reports the prevalence of US findings of joint damage in a large cohort of HS. Moreover, standard reference values of the MH cartilage thickness in HS are provided.

Prevalence and distribution of cartilage damage at the metacarpal head level in rheumatoid arthritis and osteoarthritis: an ultrasound study.

OBJECTIVES: To determine the prevalence and distribution of US-detected qualitative cartilage damage at metacarpal heads of patients with RA and hand OA. METHODS: Fifty-two RA patients and 34 patients with hand OA were enrolled. US examination of the metacarpal head cartilage from the II to V finger of both hands was performed. A total of 414 MCP joints in RA and 266 MCP joints in OA patients were scanned with a linear probe up to 22 MHz. Qualitative assessments using a previously described scoring system for cartilage damage were performed. The prevalence and distribution of cartilage damage were analysed. Multivariate regression analysis was used to determine the predictive value of age, gender, BMI, disease duration and the presence of RF and anti-CCP antibodies for US-detected cartilage damage. RESULTS: The metacarpal head cartilage was positive for cartilage damage in 35.7% (148/414) of MCP joints in RA and in 43.6% (116/266) of MCP joints in OA patients. In RA, the hyaline cartilage of the II and III metacarpal heads (bilaterally) was the most frequently affected. In OA, cartilage damage was more homogeneously distributed in all MCP joints. Multivariate regression analysis showed that age and disease duration, but not gender, BMI or autoantibody status, were independent predictors of US-detected cartilage damage in RA. CONCLUSION: Cartilage damage was found in more than one-third of the MCP joints in both RA and OA patients, and in RA patients, the II and III MCP joints were the most damaged.

Entheseal involvement in patients with systemic lupus erythematosus: an ultrasound study.

Objectives: The main objective of this study is to explore the prevalence and distribution of entheseal US changes in a cohort of SLE patients, taking as controls a group including both PsA patients and healthy subjects. The secondary objective is to investigate the correlation between the US findings and the clinical and serological data in SLE patients. Methods: Clinical and US assessment of quadriceps, patellar and Achilles tendons, and plantar fascia entheses were performed by independent rheumatologists on 65 patients with SLE, 50 patients with PsA and 50 healthy subjects. US findings were identified according to the OMERACT definitions. In SLE patients, the correlation between the US changes and the clinical and laboratory findings was evaluated. Results: US revealed one or more abnormalities in at least one enthesis in 44 out of 65 SLE patients (67.7%), 47 out of 50 PsA patients (94.0%) and 22 out of 50 healthy subjects (44.0%). In SLE patients, US findings indicating active inflammation were significantly more frequently detected than in healthy subjects (P < 0.001). The distal enthesis of the patellar tendon was the most commonly involved. The presence of power Doppler signal at the enthesis was an independent predictor of SLE disease activity (SLEDAI-2k P < 0.001, ß = 0.52; musculoskeletal-BILAG P < 0.001, ß = 0.56). Conclusion: The burden of entheseal sonographic changes was significantly higher in SLE patients than in healthy subjects, especially as regards active inflammation. The presence of power Doppler signal at the enthesis may represent a potential biomarker of SLE disease activity.

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.

Immunogenicity and safety of the booster BNT162b2 vaccine in patients with axial spondyloarthritis treated with biological disease-modifying drugs.

Background: Vaccination confers relatively short-term protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), indicating the need for booster doses. Immunocompromised individuals, including those with immune-mediated inflammatory diseases (IMIDs), may have pronounced immune response waning. Vaccine-boosted humoral and T-cell responses minimize poor coronavirus disease 19 (COVID-19) outcome without increasing adverse events (AE). There is limited evidence of third-dose vaccination in axial spondyloarthritis (AxSpA) patients. We investigated immune-response persistence after primary vaccination and immunogenicity and safety after the BNT162b2 booster vaccination. Methods: This prospective observational study enrolled an AxSpA cohort treated with interleukin-17 (IL-17) and tumor necrosis factor-alpha (TNFα) inhibitors. Serum SARS-CoV-2-specific and virus-neutralizing antibodies for humoral response and flow cytometric detection of intracellular cytokines following SARS-CoV-2-specific peptide-based stimulation for T-cell immune responses were assessed, and safety was evaluated via a clinical questionnaire. Results: Fifteen male AxSpA patients treated with TNFα (73·3%) or IL-17 (26·7%) inhibitors were enrolled and had humoral response persistence at 6 months: 905·6 ( ± 186·1 SD) and 409·1 ( ± 335·7) U/mL. Specific antibody concentrations further increased after booster vaccination to 989·7 ( ± 12·62) and 1000 U/mL and T-cell responders from 53·3% to 80%, with no differences between AxSpA (including "vaccination only" and "hybrid immunity" subgroups) and healthy control (HC) cohorts. No severe AE occurred; the AE spectrum was comparable to that of the general population. Conclusion: Immune-response persistence after primary vaccination and immunogenicity after booster vaccination were unaffected by anti-IL17 or anti-TNFα therapy with similar AE as in the general population.

SARS-CoV-2-specific humoral and cellular immune responses to BNT162b2 vaccine in Fibrodysplasia ossificans progressiva patients.

Introduction: Fibrodysplasia ossificans progressiva (FOP) is characterized by progressive heterotopic ossification triggered by various conditions, such as trauma, infection, including COVID-19 infection, and vaccination. Although SARS-CoV-2 vaccinations prevent poor outcomes in the general population, there is limited evidence on safety, immunogenicity, and efficacy of SARS-CoV-2 vaccines for inpatients with FOP. Methods: A case series of two patients with FOP focused on humoral, cellular post-vaccination response, and the incidence of adverse events after administration of the BNT162b2 vaccine (Comirnaty). Results: Injection site reactions, fever, myalgia, and fatigue were the most common adverse events (AE). Neither severe AE (SAE), nor disease flare-ups were observed. No differences between patients with FOP and healthy controls were observed in humoral and cellular responses. Conclusions: The BNT162b2 vaccine induced high humoral and cellular response levels in patients with FOP. Vaccination was not associated with SAE or disease relapse. The AEs spectrum was comparable to that of the general population.

Reliability assessment of ultrasound muscle echogenicity in patients with rheumatic diseases: Results of a multicenter international web-based study.

Objectives: To investigate the inter/intra-reliability of ultrasound (US) muscle echogenicity in patients with rheumatic diseases. Methods: Forty-two rheumatologists and 2 radiologists from 13 countries were asked to assess US muscle echogenicity of quadriceps muscle in 80 static images and 20 clips from 64 patients with different rheumatic diseases and 8 healthy subjects. Two visual scales were evaluated, a visual semi-quantitative scale (0-3) and a continuous quantitative measurement ("VAS echogenicity," 0-100). The same assessment was repeated to calculate intra-observer reliability. US muscle echogenicity was also calculated by an independent research assistant using a software for the analysis of scientific images (ImageJ). Inter and intra reliabilities were assessed by means of prevalence-adjusted bias-adjusted Kappa (PABAK), intraclass correlation coefficient (ICC) and correlations through Kendall's Tau and Pearson's Rho coefficients. Results: The semi-quantitative scale showed a moderate inter-reliability [PABAK = 0.58 (0.57-0.59)] and a substantial intra-reliability [PABAK = 0.71 (0.68-0.73)]. The lowest inter and intra-reliability results were obtained for the intermediate grades (i.e., grade 1 and 2) of the semi-quantitative scale. "VAS echogenicity" showed a high reliability both in the inter-observer [ICC = 0.80 (0.75-0.85)] and intra-observer [ICC = 0.88 (0.88-0.89)] evaluations. A substantial association was found between the participants assessment of the semi-quantitative scale and "VAS echogenicity" [ICC = 0.52 (0.50-0.54)]. The correlation between these two visual scales and ImageJ analysis was high (tau = 0.76 and rho = 0.89, respectively). Conclusion: The results of this large, multicenter study highlighted the overall good inter and intra-reliability of the US assessment of muscle echogenicity in patients with different rheumatic diseases.

Clinical effectiveness and safety of intra-articular injection of HYALGO in the management of knee osteoarthritis symptoms: A multicenter prospective study.

BACKGROUND: The reduced concentration of hyaluronic acid in the synovial fluid, leading to impairment of joint function and painful symptomatology during knee osteoarthritis (OA), can be restored by using injectable formulations of hyaluronic acid (HA) and chondroitin sulfate (CS), variable for relative composition, HA/CS molecular modifications, and injection protocols. The present study aims to assess the safety and performance of the intra-articular (IA) viscosupplementing agent HYALGO, a formulation combining 40 mg/mL HA (>1700 kDa) and 40 mg/mL CS, in the treatment of patients suffering from knee OA. METHODS: 74 patients affected by knee lesions classified as grade II and III according to Kellgren and Lawrence classification were prospectively recruited and treated with three HYALGO injections (2 mL) given one week apart. Visual analogue scale (VAS) pain changes were monitored at each injection and over-time at 6, 14, and 26 weeks of follow-up. Secondary endpoints were: Western Ontario McMaster University Osteoarthritis index (WOMAC), Patient's Global Assessment (PGA) score, Clinical Observer Global Assessment (COGA) score, Outcome Measures in Rheumatology Committee (OMERACT) and Osteoarthritis Research Society International (OARSI) responders rates. Patients were also assessed for changes in their ultrasound joint scores according to the criteria of the OMERACT US Task Force Group. RESULTS: Pain reduction was statistically significant starting from the first IA injection. Mean pain reduction from baseline to week 26 was -90.6%. At 26 weeks, WOMAC Pain was reduced by -62.7%, WOMAC Stiffness by -47.2%, WOMAC Physical Function by -54.1%; Total WOMAC by -53.8%. The VAS PGA change from baseline was -48.0 [mm] and VAS COGA -41.0 [mm]. Responders at week 26 were 78.4%. Ultrasound parameters (joint effusion, synovial thickness, and popliteal cysts) improved or remained stable from baseline to week 6. CONCLUSIONS: Three injections of HYALGO were safe and effective to manage symptomatic knee OA, with a beneficial effect that increased progressively over time, peaking 6 months after injection.

Serum calprotectin may reflect inflammatory activity in patients with active rheumatoid arthritis despite normal to low C-reactive protein.

Approximately half of patients with rheumatoid arthritis (RA) have normal C-reactive protein (CRP) levels. Calprotectin is a promising and likely more specific biomarker of disease activity than conventionally used acute phase reactants. We aimed to analyse the levels of serum calprotectin in RA patients with clinically active disease and with normal/low CRP. A total of 160 RA patients underwent clinical examination (DAS28-ESR and CDAI). The levels of calprotectin were analysed in patients with moderate to high disease activity with normal/low CRP levels and in 32 healthy subjects. The discriminatory capacity of calprotectin to identify clinically active patients in spite of normal/low CRP was assessed using ROC curves. Out of all RA patients, 74/160 (46.3%) were in remission or had low disease activity according to DAS28 and had normal/low CRP levels. However, 51/160 (32%) had normal/low CRP levels despite having moderate to high disease activity. In these patients, calprotectin levels were significantly higher than those in patients who had normal/low CRP and were in remission or showed low disease activity (2.7 ± 1.5 vs. 2.1 ± 1.2 µg/mL, p = 0.043), which differed from those in healthy subjects (2.7 ± 1.5 vs. 1.9 ± 1.2 µg/mL, p = 0.011). The discriminatory capacity for calprotectin to distinguish clinically active vs. inactive disease despite normal/low CRP using AUC of the DAS28 was 0.607 (95% CI 0.503 to 0.711, p = 0.043). The present study demonstrates that calprotectin may reflect inflammatory activity in RA patients where CRP fails to do so.

Relationship between serum calprotectin (S100A8/9) and clinical, laboratory and ultrasound parameters of disease activity in rheumatoid arthritis: A large cohort study.

BACKGROUND: Calprotectin may be a sensitive biomarker of rheumatoid arthritis (RA) disease activity. OBJECTIVES: In the current study, we investigated whether calprotectin is a better biomarker than CRP for predicting clinical activity and ultrasound parameters in patients with RA. METHODS: A total of 160 patients with RA underwent clinical (swollen joint count-SJC, tender joint count-TJC, Disease Activity Score-DAS28, Clinical Disease Activity Index-CDAI, and simplified Disease Activity Index-SDAI) and ultrasound (German US7) examination. Clinical and laboratory measures were correlated with ultrasound findings using Spearman´s correlation coefficient. Differences in serum calprotectin levels in patients with variable disease activity according to the DAS28-ESR and CDAI scores were assessed using ANOVA. Multivariate regression analysis was used to determine the predictive values of calprotectin, CRP and SJC for CDAI and PD US synovitis scores. RESULTS: Serum calprotectin was significantly associated with DAS28-ESR (r = 0.321, p<0.001), DAS28-CRP (r = 0.346, p<0.001), SDAI (r = 0.305, p<0.001), CDAI (r = 0.279, p<0.001) scores and CRP levels (r = 0.556, p<0.001). Moreover, calprotectin was significantly correlated with GS (r = 0.379, p<0.001) and PD synovitis scores (r = 0.419, p<0.001). The multivariate regression analysis showed that calprotectin is a better predictor of the CDAI score and PD US synovitis than CRP. CONCLUSIONS: The results of this study support an additional role of calprotectin in assessing inflammatory activity in patients with RA.

The relationship between synovitis quantified by an ultrasound 7-joint inflammation score and physical disability in rheumatoid arthritis - a cohort study.

BACKGROUND: Restoring normal physical functioning is a major therapeutic aim in the management of rheumatoid arthritis (RA). It is unknown, whether the extent of synovial inflammation quantified by musculoskeletal ultrasound (US) can predict current or future capacity for physical functioning. To answer this question we investigated the longitudinal relationship between physical function assessed by the health assessment questionnaire (HAQ) and the German 7-joint ultrasound score (US7S) in a prospective cohort of patients with RA. METHODS: Patients with RA (n = 185 (46 with incident and 139 with prevalent disease) were followed for 30.9 ± 9.1 months. Baseline and annual assessments comprised the disease activity score in 28 joints (DAS28), HAQ and US7S. The US7S includes semiquantitative measurements of synovitis assessed by greyscale (GS) and power Doppler (PD) in seven joints of the clinically dominant hand and foot, which are then aggregated in PD and GS synovitis sum-scores (PDsynSS and GSsynSS). A linear mixed-effect model was used to assess the longitudinal relationship between GSsynSS, PDsynSS and HAQ. We used standard and time-lag models to explore the association between HAQ, and GSsynSS, PDsynSS and DAS28 measured at the same time or at the previous visit 12 months ago, respectively. RESULTS: When the standard model was applied, in univariate analyses HAQ score was positively associated with GSsynSS and PDsynSS with ß coefficients significantly higher in incident than in prevalent disease. In multivariate analysis both synSSs were individually no longer significant predictors of HAQ score. When using the time-lag model, after adjustment for the previous DAS28 or HAQ score, both PDsynSS and GSsynSS were significantly and negatively associated with the current HAQ. CONCLUSIONS: US7 PD and GS synovitis sum-scores alone were positively associated with current functional status reflected by the HAQ in patients with RA, and this relationship was stronger in patients with early disease. When combined with the DAS28 or HAQ, US7 PD and GS synovitis sum-scores were predictive of the change in HAQ score over one year.

Serum Calprotectin Discriminates Subclinical Disease Activity from Ultrasound-Defined Remission in Patients with Rheumatoid Arthritis in Clinical Remission.

OBJECTIVE: Clinical remission in some patients with rheumatoid arthritis (RA) may be associated with ongoing synovial inflammation that is not always detectable on clinical examination or reflected by laboratory tests but can be visualized by musculoskeletal ultrasound. The goal of our study was to determine the levels of serum calprotectin, a major leukocyte protein, in patients with RA in clinical remission and to investigate the ability of serum calprotectin levels to distinguish patients in ultrasound-defined remission from those with residual ultrasound subclinical inflammation. METHODS: Seventy RA patients in clinical remission underwent clinical and ultrasound examination. Ultrasound examination was performed according to the German US7 score. Ultrasound remission was defined as grey scale (GS) range 0-1 and power Doppler (PD) range 0. The levels of serum calprotectin and C-reactive protein (CRP) were determined. The discriminatory capacity of calprotectin and CRP in detecting residual ultrasound inflammation was assessed using ROC curves. RESULTS: The total number of patients fulfilling the DAS28-ESR, DAS28-CRP, SDAI and CDAI remission criteria was 58, 67, 32 and 31, respectively. Residual synovial inflammation was found in 58-67% of the patients who fulfilled at least one set of clinical remission criteria. Calprotectin levels were significantly higher in patients with residual synovial inflammation than in those with ultrasound-defined remission (mean 2.5±1.3 vs. 1.7±0.8 µg/mL, p<0.005). Using ultrasound-defined remission criteria, calprotectin had an AUC of 0.692, p<0.05 using DAS28-ESR remission criteria and an AUC of 0.712, p<0.005 using DAS28-CRP remission criteria. Calprotectin correctly distinguished ultrasound remission from subclinical activity in 70% of patients. CRP (AUC DAS28-ESR = 0.494, p = NS; AUC DAS28-CRP = 0.498, p = NS) had lower and insignificant discriminatory capacity. CONCLUSION: The present study demonstrates the potential of calprotectin to distinguish RA patients in both clinical and ultrasound-defined remission from patients in clinical remission but with residual subclinical disease activity.

Serum calprotectin (S100A8/9): an independent predictor of ultrasound synovitis in patients with rheumatoid arthritis.

INTRODUCTION: Calprotectin, a heterodimeric complex of S100A8/9 (MRP8/14), has been proposed as an important serum biomarker that reflects disease activity and structural joint damage in rheumatoid arthritis (RA). The objective of this cross-sectional study was to test the hypothesis that calprotectin is associated with clinical and ultrasound-determined disease activity in patients with RA. METHODS: A total of 37 patients with RA (including 24 females, a mean disease duration of 20 months) underwent a clinical examination and 7-joint ultrasound score (German US-7) of the clinically dominant hand and foot to assess synovitis by grey-scale (GS) and synovial vascularity by power Doppler (PD) ultrasound using semiquantitative 0-3 grading. The levels of serum calprotectin and C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were determined at the time of the ultrasound assessment. We analysed the relationship between serum calprotectin level, traditional inflammatory markers, and ultrasound-determined synovitis. RESULTS: The levels of serum calprotectin were significantly correlated with swollen joint count (r = 0.465, p < 0.005), DAS28-ESR (r = 0.430, p < 0.01), ESR (r = 0.370, p < 0.05) and, in particular, CRP (r = 0.629, p < 0.001). Calprotectin was significantly associated with GS (r = 0.359, p < 0.05) and PD synovitis scores (r = 0.497, p < 0.005). Using multivariate regression analysis, calprotectin, adjusted for age and sex, was a better predictor of PD synovitis score (R(2) = 0.765, p < 0.001) than CRP (R(2) = 0.496, p < 0.001). CONCLUSIONS: The serum levels of calprotectin are significantly associated with clinical, laboratory and ultrasound assessments of RA disease activity. These results suggest that calprotectin might be superior to CRP for monitoring ultrasound-determined synovial inflammation in RA patients.