Diagnostic and prognostic role of serum interleukin-6 and carotid ultrasonography to detect subclinical atherosclerosis in patients with RA and ANCA-associated vasculitis.

ANCA-associated vasculitis (AAV) can affect multiple organs with severe life-threatening manifestations. Disease monitoring is difficult due to a lack of defined biomarkers. We aimed to assess the diagnostic role of serum interleukin-6 and vascular ultrasonography in AAV and subclinical atherosclerosis. The study included 20 AAV patients and two control groups of 34 patients with rheumatoid arthritis (RA) and 35 healthy controls. The levels of Il-6, carotid intima-media thickness test (CIMT), atherosclerotic plaque, and degree of stenosis were investigated. A GRACE-risk score was calculated for AAV and RA patients. The AAV patients had elevated levels of IL-6 (115 ± 23.96) compared to the RA patients (91.25 ± 42.63) and the healthy controls (15.65 ± 3.30), p < 0.001. IL-6 showed a diagnostic accuracy of 73% in distinguishing AAV from RA patients (AUC = 0.730; 95% CI 0.591 to 0834). In the AAV group, CIMT was 1.09, above the upper reference value of 0.90, p < 0.001. The AAV patients had a higher median GRACE risk score, and 60% of them had a high risk of cardiovascular events as compared to 35% of the RA patients. Sonography of extracranial vessels and serum levels of IL-6 can be used in daily clinical practice to diagnose and monitor patients with AAV.

Recent Insights into the Role of DNA Methylation and Histone Modifications in Systemic Sclerosis: A Scoping Review.

Systemic sclerosis is a complex idiopathic disease originating from an intricate interplay between genetic susceptibility, environmental factors, and epigenetic modifications. This scoping review aims to map the advancements made regarding DNA methylation abnormalities and histone modifications in systemic sclerosis in the past decade. A literature search was conducted using three electronic databases (Scopus, Web of Science and PubMed) to identify relevant articles. A total of 44 studies were selected for this review, demonstrating the critical contribution of epigenetic perturbations in multiple cell types to disease pathogenesis. In conclusion, this scoping review has elucidated the significant discoveries made in the past decade regarding the role of DNA methylation and histone modifications in systemic sclerosis. Further progress in the field could lead to the development of novel treatment possibilities targeting epigenetic marks.

Prevalence and characteristics of subclinical giant cell arteritis in polymyalgia rheumatica.

OBJECTIVE: The main objective of this study was to analyse the prevalence and characteristics of subclinical GCA in patients with PMR. METHODS: This was a cross-sectional multicentre international study of consecutive patients with newly diagnosed PMR without symptoms or signs suggestive of GCA. All patients underwent US of the temporal superficial, common carotid, subclavian and axillary arteries. Patients with halo signs in at least one examined artery were considered to have subclinical GCA. The clinical, demographic and laboratory characteristics of the PMR group without subclinical vasculitis were compared with subclinical GCA, and the pattern of vessel involvement was compared with that of a classical single-centre GCA cohort. RESULTS: We included 346 PMR patients, 267 (77.2%) without subclinical GCA and 79 (22.8%) with subclinical GCA. The PMR patients with subclinical GCA were significantly older, had a longer duration of morning stiffness and more frequently reported hip pain than PMR without subclinical GCA. PMR with subclinical GCA showed a predominant extracranial large vessel pattern of vasculitic involvement compared with classical GCA, where the cranial phenotype predominated. The patients with PMR in the classical GCA group showed a pattern of vessel involvement similar to classical GCA without PMR but different from PMR with subclinical involvement. CONCLUSION: More than a fifth of the pure PMR patients had US findings consistent with subclinical GCA. This specific subset of patients showed a predilection for extracranial artery involvement. The optimal screening strategy to assess the presence of vasculitis in PMR remains to be determined.

Subclinical giant cell arteritis increases the risk of relapse in polymyalgia rheumatica.

OBJECTIVE: The aim of the present study was to determine the clinical significance of subclinical giant cell arteritis (GCA) in polymyalgia rheumatica (PMR) and ascertain its optimal treatment approach. METHODS: Patients with PMR who fulfilled the 2012 European Alliance of Associations for Rheumatology/American College of Rheumatology Provisional Classification Criteria for PMR, did not have GCA symptoms and were routinely followed up for 2 years and were stratified into two groups, according to their ultrasound results: isolated PMR and PMR with subclinical GCA. The outcomes (relapses, glucocorticoid use and disease-modifying antirheumatic drug treatments) between groups were compared. RESULTS: We included 150 patients with PMR (50 with subclinical GCA) with a median (IQR) follow-up of 22 (20-24) months. Overall, 47 patients (31.3 %) had a relapse, 31 (62%) in the subclinical GCA group and 16 (16%) in the isolated PMR group (p<0.001). Among patients with subclinical GCA, no differences were found in the mean (SD) prednisone starting dosage between relapsed and non-relapsed patients (32.4±15.6 vs 35.5±12.1 mg, respectively, p=0.722). Patients with subclinical GCA who relapsed had a faster prednisone dose tapering in the first 3 months compared with the non-relapsed patients, with a mean dose at the third month of 10.0±5.2 versus 15.2±7.9 mg daily (p<0.001). No differences were found between relapsing and non-relapsed patients with subclinical GCA regarding age, sex, C reactive protein and erythrocyte sedimentation rate. CONCLUSIONS: Patients with PMR and subclinical GCA had a significantly higher number of relapses during a 2-year follow-up than patients with isolated PMR. Lower starting doses and rapid glucocorticoid tapering in the first 3 months emerged as risk factors for relapse.

JAK inhibitors improve ATP production and mitochondrial function in rheumatoid arthritis: a pilot study.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease associated by inflammation of the synovial tissue and autoantibody production. Oxidative stress and free radicals are known to be indirectly implicated in joint damage and cartilage destruction in RA. Several studies describe the presence of mitochondrial dysfunction in RA, but few of them follow the dynamics in energy parameters after therapy. The aim of our investigation is to evaluate the direct effect of JAK inhibitors on cellular metabolism (and under induced oxidative stress) in RA patients. Ten newly diagnosed RA patients were included in the study. Peripheral blood mononuclear cells (PBMCs) and plasma were isolated before and 6 months after therapy with JAK inhibitors. A real-time metabolic analysis was performed to assess mitochondrial function and cell metabolism in PBMCs. Sonographic examination, DAS28 and conventional clinical laboratory parameters were determined also prior and post therapy. A significant decrease in proton leak after therapy with JAK inhibitors was found. The increased production of ATP indicates improvement of cellular bioenergetics status. These findings could be related to the catalytic action of JAK inhibitors on oxidative phosphorylation which corresponds to the amelioration of clinical and ultra-sonographic parameters after treatment. Our study is the first to establish the dynamics of mitochondrial parameters in PBMCs from RA patients before and after in vivo therapy with JAK inhibitors.

The COVID-19 pandemic's impact on rheumatic disease patients' satisfaction with access to medical services.

The COVID-19 hurt various lifestyle aspects, especially the treatment and follow-up of patients with chronic diseases such as autoimmune inflammatory rheumatic diseases (RD). The new circumstances changed the frequency of medical examinations and the way patients with rheumatic diseases are followed up. The objective is to study the impact of COVID-19 on RD patients' satisfaction with access to medical services. A national multicenter observational cross-sectional anonymous online survey was conducted on patients with RD using a specially developed web-based platform and structured questionnaire https://rheumatologycovid19.bg/ . The study was carried out with the support of intra-university project №6/2022 MU-Plovdiv. 1288 patients participated, with an average age of 47.03 (SD ± 12.80 years), of whom 992 (81.6%) were women. The questionnaire contained 41 questions grouped into 5 panels. Descriptive statistics were used-mean, alternative analysis, logistic regression and Decision Tree using the CRT (classification and regression trees) method. The study found that RD patients' satisfaction with access to medical services was influenced by communication type and the frequency of visits to the rheumatologist, difficulties in prescribing and finding medicines and the presence of comorbidities. The likelihood of patients' satisfaction with their rheumatologist was 5.5 and 3 times higher for in-person and other means of communication, respectively, compared to those without any communication. The relative share of patients who communicated by phone was larger (59%) compared to pre-pandemic (41%), where direct contact with the physician prevailed (80%). The results of the study confirmed the need to optimize remote access to medical care for patients with RD during the pandemic.

Effect of the body mass index, basal metabolic rate, and body fat on the radiofrequency echographic multi-spectrometry (REMS)-based bone mineral density and fracture risk: a cross-sectional study.

Radiofrequency echographic multi-spectrometry (REMS) is a method to assess bone mineral density (BMD) of the axial skeleton, fragility score (FS), body mass index (BMI), basal metabolic rate (BMR), and body fat (BF) in %. The aim of the study was to investigate the influence of the BMI, BMR, and BF on the BMD and fracture risk with REMS. We conducted a cross-sectional study among 313 women, aged 20-90 years who underwent a screening for osteoporosis with REMS. Kruskal-Wallis was used to analyze the differences in BMI, BMR, and BF between the groups according to the BMD: normal BMD, osteopenia and osteoporosis and differences in the FS, fracture risk assessment (FRAX) for major osteoporotic fractures and for hip fractures (HF) according to the BMI groups: underweight, normal weight, overweight, obese, and extreme obese. Linear regression was used to assess the correlations BMI-BMD, BMR-BMD, and BF-BMD. BMI, BMR, and BF differed significantly between the groups according to the BMD (p < 0.001, p = 0.028, and p < 0.001, respectively). BMR showed high positive correlation to BMD (R = 0.765) with 95% confidence interval (CI) [0.715, 0.807] and significance of p < 0.001. BMI correlated significantly to BMD (p < 0.001), the correlation was low positive (R = 0.362) with 95% CI [0.262, 0.455]. In the BMI groups, there was significant difference in FRAX for HF and FS with p value 0.014 and < 0.001, respectively. Subjects with low BMI, BMR, and BF are at high risk for osteoporosis. Underweight women show significantly high fracture risk, assessed with FRAX and FS.

High-resolution musculoskeletal ultrasonography and elastography for eosinophilic fasciitis diagnosis and follow-up: a case-based review.

Eosinophilic fasciitis (EF) remains a rare condition without precise diagnostic criteria due to common symptoms with other autoimmune diseases requiring broad differential diagnosis. This paper describes the use of high-resolution musculoskeletal ultrasonography and elastography in the diagnosis and follow-up of eosinophilic fasciitis through the case of a 56-year-old male patient. In addition to laboratory data, instrumental data, and biopsy, musculoskeletal ultrasonography (US) was used both in the diagnostic process and in the follow-up period for an objective assessment of the changes in the patient's condition and response to treatment. The US showed disorganization of the myofibrils adjacent to the superficial fascia, edema, and thickening of the fascia and subcutaneous edema. In addition, the use of shear-wave elastography (SWE) demonstrated significantly reduced skin elasticity. High-frequency musculoskeletal ultrasound in combination with SWE is an effective method both for the diagnosis of EF and for the follow-up of the changes occurring after therapy. Based on the fact that it can easily differentiate the substrate of involvement, such as skin, subcutaneous tissue, or muscle fascia, ultrasound can be used to distinguish EF from other skin and muscle diseases.

First multi-center retrospective study assessed the compliance with and persistence of biological therapies in Bulgarian population with rheumatoid arthritis.

Rheumatoid arthritis is an inflammatory joint disease that causes progressive joint damage, leading to severe disability. Early diagnosis, optimal therapy, and strict adherence to the prescribed medication are key factors that allow for the cessation of the disease progression and the preserving of the patient's quality of life. The objective of this study was to estimate the compliance to and persistence of biologic disease-modifying anti-rheumatic drugs (bDMARDs) among the Bulgarian population with RA. This retrospective observational cohort study included 179 patients, who were tracked over a 36-month period. During baseline and subsequent follow-up visits (at months 6, 12, 24, and 36), we monitored the disease activity, side effects, medication tolerability and effectiveness, compliance, and persistence to the prescribed biologic agent. The compliance with bDMARDs among Bulgarian patients with RA was 85.5% in the first year, 76.0% in the second year, and 63.7% in the third year. The Infliximab cohort showed the lowest compliance rate (50%), with the other subgroups bDMARDs having similar results (64-70%) during the period of observation. The median therapy duration across all patient cohorts is 61.9 months (IQR 55.7-67.6). Our study did not establish any significant impact of gender, age and disease duration, concomitant treatment with methotrexate, type of biologic agent and previous exposure to biological agents on the treatment adherence. The compliance with and persistence of the prescribed bDMARD among the Bulgarian population with RA is unsatisfactory. Therapy interruption and nonadherence to recommended therapy are associated with disease progression and patient disability. The consequences include not only financial burdens but also psychosocial and physical impacts.

An observational study of the radiofrequency echographic multi-spectrometry (REMS)-based fragility score of the lumbar spine and total fracture risk at 5 years in women.

A novel fragility score (FS) parameter, obtained during radiofrequency echographic multi-spectrometry (REMS), was developed to estimate the ultrasound-based skeletal fragility. The aim of our study is to assess the REMS-based FS of the lumbar spine (LS) among the Bulgarian women and to compare their characteristics acquired with REMS between fracture risk classes corresponding to a total fracture risk at 5 years for major osteoporotic fractures (MOF). A total of 100 Bulgarian women, who underwent a screening for osteoporotic fracture risk using the REMS technology, were included in a prospective observational study. The mean age was 60 years (years) ± 13.9 standard deviations. We assessed the FS of the LS and for each subject. The fracture risk class (R1-R7) was identified using a table combining measured REMS T score and FS values. The mean FS was 36.9 ± 17.4 SD (range: 18.5-84.3). Twelve subjects (12%) were classified into the R6 group, twenty-three (23%) into the R5, sixty-one (61%) into R4, and four (4%) into R3. Statistical analysis showed significant difference in age, height, BMD, T score, Z score, age of menopause, FRAX for MOF, and FRAX for hip fractures between the risk class groups. This is the first study which showed the REMS-based FS of the lumbar spine among the Bulgarian women. T score alone is not a good predictor of fractures. Our study showed that its use in combination with the fragility score obtained during REMS offers a robust assessment of the fracture risk at 5 years for MOF.

Adherence to biological therapies in patients with rheumatoid arthritis: a retrospective cohort study.

The advent of biologic disease-modifying antirheumatic drugs has dramatically changed the comprehensions of treatment and long-term prognosis in patients with rheumatoid arthritis. The potent therapeutic results can only be achieved if the patients adhere to prescribed medications. The objective of this study was to estimate the impact of age, gender, duration of the disease, concomitant Methotrexate therapy, prior exposure to biologic agents, disease activity, functional capacity, and health-related quality of life on adherence to biologic treatment among Bulgarian population with rheumatoid arthritis. This was a retrospective observational cohort study that included 179 patients. At the baseline visit and subsequent follow-up assessments at 6, 12, 24 and 36 months, patients were interviewed by a physician and underwent physical examinations. We monitored the changes in disease activity, functional capacity and health-related quality of life on each time point. Univariate and multivariate binary logistic regression was used to determine the prognostic value of possible predictors of treatment adherence. Our findings showed that only DAS28 score [odd ratio (OR) = 1.174; 95% CI 1.74-2.362] and HAQ score (OR 2.803; 95% CI 1.428-5.503) remained significant for the treatment adherence throughout the study period. The adherence to the biologic disease-modifying anti-rheumatic drugs among Bulgarian patients with rheumatoid arthritis is suboptimal. A multifaceted and comprehensive knowledge of the influencing factors can be useful for the development of different strategies that can improve treatment adherence.

Ochronotic arthropathy in the context of spondyloarthritis differential diagnosis: a case-based review.

Alkaptonuria is a disease often forgotten because of its rarity. Its pathogenic mechanism is the deficiency of one of the enzymes of the tyrosine degradation pathway-homogentisate-1, 2-dioxygenase, which sequelae is accumulation and deposition of its metabolite homogentisic acid in connective tissues and urine. Alkaptonuria presents as a clinical triad-darkening urine upon prolonged exposure to air, pigmentation of connective tissues and debilitating arthropathy. We present a case report of a 67-year old patient with alkaptonuria who presented with the clinical triad, but was mistakenly diagnosed as having ankylosing spondylitis in the past. Currently there is no treatment for the disease hence the management strategy was focused on symptoms control with analgesics, physical therapy, dietary modification, vitamin C supplementation, and joint arthroplasty. Alkaptonuria's clinical features are extensively described in the literature and despite the fact that it is a rare disease, due to the similar radiographic changes with spondyloarthropathies, it should be included in the differential diagnosis in young patients presenting with severe joint involvement. Early recognition of the disease is necessary since its natural evolution is joint destruction leading to significant reduction in the quality of life. Alkaptonuria's articular features in the spine and peripheral tissues are well described using the classical imaging techniques. Musculoskeletal ultrasonography shows a characteristic set of findings in the soft tissues, including synovium, cartilage, tendons and entheses.

Prevalence of low bone mineral density at axial sites and fracture risk in Bulgarian population.

Background: Osteoporosis is a common chronic disease characterized by low bone mineral density (BMD) and microarchitectural deterioration of the bone, which are associated with increased risk of fragility fractures. Currently the most popular tool is the fracture risk assessment model FRAX to calculate the 10-year probability of major osteoporotic fractures (MOF) and hip fractures (HF). Objective: To investigate the prevalence of low BMD at axial sites and fracture risk in Bulgarian population. Methods: We retrospectively analyzed dual energy X-ray absorptiometry (DXA) scan results of 12 478 subjects. Scan results included BMD and T-score assessments of lumbar spine and femoral neck. FRAX major osteoprotic fracture (MOF) and FRAX hip fracture (HF) were assessed in subjects between 40 and 90 years using BMD values. Results: Of total 12478 subjects, 12119 were women and 359 were men. The mean age of the subjects was 61 years (yrs.) ± 10 yrs. The overall prevalence of low BMD at the lumbar spine was 6084/9336 subjects (65.2%). 3502/9336 subjects (37.5%) were considered as osteopenic and 2582/9336 subjects (27.7%) were considered as osteoporotic. The overall prevalence of low BMD at the femoral neck was 2036/3140 (64.8%). 1641/3140 subjects (52.3%) were classified as osteopenic and 395/3 140 subjects (12.6%) were classified as osteoporotic. The mean values of FRAX MOF and FRAX HF increased significantly with increasing the age interval. Conclusion: This study is the largest epidemiological research in Bulgaria up to date about the prevalence of low BMD at axial sites.

Tofacitinib in the treatment of skin and musculoskeletal involvement in patients with systemic sclerosis, evaluated by ultrasound.

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disease characterized by fibrosis of the skin and internal organs, autoimmunity-driven damage and vasculopathy. The current approved disease-modifying treatments have limited efficacy, and treatment is guided toward alleviating organ complications. Thus, there is an unmet need for discovering new effective treatment options. There is recent evidence that the JAK/STAT signaling pathway is markedly activated in SSc patients. To assess the efficacy and safety of tofacitinib (TOF) on skin and musculoskeletal involvement as compared to methotrexate (MTX) in systemic sclerosis (SSc). In this 52-week pilot study, 66 patients with SSc were enrolled: 33 patients received 5 mg of oral TOF twice a day; 33 received 10 mg of MTX weekly. The proportion of dcSSc and lcSSc patients was similar (dcSSc: 42% TOF group and 36% MTX group; lcSSc: 58% TOF group and 64% MTX group). The primary outcome was the change in the modified Rodnan skin score (mRSS). Secondary outcomes included ultrasound (US) skin thickness and musculoskeletal involvement (US10SSc score). Digital ulcers (DUs) and adverse events (AEs) were documented through the treatment. Both groups had similar characteristics and medians on the outcome measures at baseline. At week 52, the TOF median mRSS was significantly lower than the MTX (p < 0.001) with a mean reduction of 13 points versus MTX 2.57. The mean percent improvement in the TOF group was 44% higher than in the MTX group. TOF median US skin thickness was significantly lower than MTX (p < 0.001), with a mean reduction of 0.31 mm versus 0.075 mm in the MTX group. The US10SSc median score was significantly lower in the TOF group (p = 0.002); mean reduction of 10.21 versus 5.27 in the MTX group. Healing of DUs with no new occurrences was observed in the TOF group. There was no significant difference between the groups in the number of AEs from baseline to week 52. TOF showed greater efficacy than MTX in reducing mRSS, skin thickness and musculoskeletal involvement in SSc and a satisfactory safety profile.

Enthesopathy and involvement of synovio-entheseal complex in systemic sclerosis: an ultrasound pilot study.

OBJECTIVES: SSc is a chronic autoimmune disease characterized by inflammation of the skin and multiple internal organs. Articular involvement is one of the main features of SSc, and typical hallmarks of SpA have been found in SSc patients. The aim of the present study was to estimate the prevalence of entheseal and synovio-entheseal complex (SEC) alterations in a cohort of SSc patients. METHODS: One hundred SSc patients and 25 healthy subjects were included in this cross-sectional study. The enthesis sites of lateral epicondylar common extensor tendons (CET) and the enthesis of the Glasgow Ultrasound Enthesis Scoring System were evaluated. SEC involvement was evaluated only at CET enthesis. RESULTS: In SSc, the Glasgow Ultrasound Enthesis Scoring System score was significantly higher (median 4.0, interquartile range 2.0-7.0) than in controls (median 1.0, interquartile range 0.0-3.0) (P < 0.0001). CET enthesis of SSc patients showed more frequent US B-mode alterations than that of controls (χ2 = 11.47, P = 0.0007 for size; χ2 = 13.79, P = 0.0002 for cortical irregularity, χ2 = 5.24, P = 0.022 for calcification/enthesophytes). Power Doppler US signal at CET enthesis was significantly more frequent in SSc patients than in healthy controls (χ2 = 9.11, P = 0.0025), as was the concomitant SEC involvement (χ2 = 8.52, P = 0.0035). CONCLUSION: These data show that SSc patients frequently present US features of enthesopathy. Moreover, CET enthesopathy was correlated with SEC inflammation, suggesting that entheseal inflammation in SSc may share the same micro-anatomical targets as found in SpA.

Serum YKL-40 and IL-6 levels correlate with ultrasound findings of articular and periarticular involvement in patients with systemic sclerosis.

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by vascular, immune and fibrotic abnormalities in the skin and in many internal organs. New biomarkers with predictive value associated with target organ involvement are needed. The up-regulation of IL-6 production is associated with the disease activity and in the development of cardiopulmonary manifestations in SSc patients. The protein YKL-40 is a promising and intensively investigated biomarker related to inflammatory and tumor diseases. The objective of the study was to investigate how serum levels of YKL-40 and IL-6 correlate with articular and periarticular involvement in patients with SSc assessed by high-frequency ultrasonography. 59 SSc patients (56 women, 3 men) and 23 age-matched healthy subjects (21 women and 2 men) were investigated for serum YKL-40 and IL-6 (by ELISA). All the patients and healthy controls underwent clinically and high-frequency ultrasound assessment of articular and periarticular structures. Joint involvement was scored according to the new US10SSc score. Clinical data about the SSc patients showed significantly higher mRSS in the dcSSc patients (p = 0.015). Clinical synovitis was diagnosed in 16.9% of all patients: 22.5% of the dcSSc group and 10.7% of the lcSSc group (p = 0.306). On the other hand, US synovitis was detected in a higher percentage: 44% of all SSc patients; 54.8% of the dcSSc group and 32% of the lcSSc patients (p = 0.116). Clinical tenosynovitis was established in 6.7% of all patients: 9.7% of the dcSSc group and 3.5% of the lcSSc group (p = 0.614). US tenosynovitis was detected at a higher rate: 27% of all patients; 32.25% of the dcSSc group and 21.4% of the lcSSc group (p = 0.393). Serum level of YKL-40 was significantly higher in SSc patients (115.62 ng/ml ± 89.51, median 86.76) compared to the healthy controls (46.28 ng/ml ± 18.91, median 44.02), p < 0.001. IL-6 level was also significantly higher in the patient group (27.60 ± 48.80 pg/ml; median 8.32) vs. the healthy controls (5.79 ± 2.46 pg/ml, median 5.52). In the patient subgroups, YKL-40 and IL-6 levels were significantly elevated in dcSSc compared to lcSSc patients: YKL-40 dcSSc (159.52 ng/ml ± 102.81; median 136.20 ng/ml) vs. lcSSc patients (89.31 ng/ml ± 50.36; median 68.03 ng/ml;), p < 0.001; IL-6 dcSSc patients (49.64 pg/ml ± 46.37; median 16.36 pg/ml) vs. lcSSc patients (13.22 pg/ml ± 8.95; median 8.65 pg/ml), p = 0.048. A statistically significant correlation of high magnitude (rs = 0.884, p < 0.001) was observed between YKL-40 and the ultrasound 10 Systemic sclerosis score (US10SSc) and between IL-6 and the US10SSc score (rs = 0.808, p < 0.001). Serum YKL-40 and IL-6 in combination with US may have a potential role in defining disease activity and stratification, predicting organ involvement, and in the prognosis of SSc.