Metabolites of C-reactive protein and vimentin are associated with disease activity of axial spondyloarthritis.

OBJECTIVES: Non-radiographic (nr-axSpA) and radiographic (AS) forms of axial spondyloarthritis (axSpA) share clinical features, but have different radiographic patterns. Radiographic progression is not associated with the current disease activity biomarkers. We investigated a matrix metalloproteinase mediated metabolite of C-reactive protein (CRPM) and two biomarkers of citrullinated vimentin (VICM and anti-MCV) as novel biomarkers of disease activity. METHODS: AxSpA patients (n=121 nr-axSpA and n=72 AS) were characterised by activity (AS disease activity score with CRP [ASDAS-CRP], Bath AS disease activity index [BASDAI] and functional index [BASFI]), radiographic scores and quality of life questionnaires. CRPM, VICM and anti-MCV levels were analysed by ELISA in serum. Asymptomatic controls (n=100) were used as reference. Multiple regression investigated association with disease activity and diagnostic potential. RESULTS: CRPM and VICM levels were increased in AS compared to nr-axSpA (11.9nM vs. 10.2nM, p<0.001 and 4.92nM vs. 3.77nM, p=0.0025). Anti-MCV was similar in both axSpA subgroups, but lowered in controls. In nr-axSpA, CRPM correlated with CRP (ρ=0.33, p<0.001) and VICM (ρ=0.29, p=0.001); in AS, VICM correlated with CRP (ρ=0.34, p=0.0032) and ESR (ρ=0.38, p<0.001). ASDAS-CRP correlated with CRPM and anti-MCV, but when adjusting for CRP the correlation only remained with CRPM. CRPM and VICM separated the subgroups with odds ratios of 1.19 and 1.10 adjusted for age, gender, BMI, and disease duration. VICM lost significance when adjusting for CRP. CONCLUSIONS: CRPM was associated with disease activity in axSpA, and CRPM and VICM separated the axSpA groups. This study indicates that serological biomarkers may be novel biomarkers in axSpA.

[Differential diagnosis of monoarthritis]. / Diferenciální diagnostika monoartritid.

Making the diagnosis of monoarthritis can be quite difficult, because in contrast with polyarthritis just a few clinical data is available and wide diagnostic spectrum is present.The diagnosis of inflammatory rheumatic disease is usually in responsibility of a rheumatologist, but we know from experience that is necessary to carry out the basal differential diagnostic assessment as soon as possible to begin the optimal therapy. General practitioners and orthopaedists are usually first to face this problem.Monoarthritis can be divided into non-inflammatory arthritis where activated osteoarthritis and trauma belongs and inflammatory arthritis, which include gouty arthritis, chondrocalcinosis, infectious arthritis, juvenile idiopathic arthritis, spondylitis, incipient rheumatoid arthritis and many others.The article also focuses on the management of patients with monoarthritis where detailed history, careful clinical joint examination and the nature of arthritis assessment is necessary for differential diagnostic considerations. Our balance sheet further facilitate imaging, arthrocentesis with the analysis of synovial fluid and of course the laboratory examination.

Publisher Correction: Metabolites of type I, II, III, and IV collagen may serve as markers of disease activity in axial spondyloarthritis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cross-sectional study of patients with axial spondyloarthritis fulfilling imaging arm of ASAS classification criteria: baseline clinical characteristics and subset differences in a single-centre cohort.

OBJECTIVE: This study compared demographic, clinical and laboratory characteristics between patients with radiographic and non-radiographic axial spondyloarthritis (axSpA). METHODS: In this single-centre cross-sectional study, a total of 246 patients with axSpA fulfilling the imaging arm of Assessment of SpondyloArthritis International Society classification criteria were recruited. A total of 140 patients were diagnosed as non-radiographic axial spondyloarthritis (nr-axSpA), and 106 patients had ankylosing spondylitis (AS). Sociodemographic characteristics, disease manifestations, clinical and laboratory disease activity and their differences between subsets were analysed. P values below 0.05 with CI 95% were considered statistically significant. RESULTS: More nr-axSpA patients were women (61.4%) compared with 24.7% of AS patients. First symptoms developed earlier in AS patients compared with nr-axSpA (23.0 (IQR 17.5-30.0) vs 27.8 (IQR 21.0-33.7) years, p=0.001). Disease manifestations did not differ, but patients with nr-axSpA experienced peripheral arthritis more frequently (35.7% vs 17.0%, p=0.001) with less hip involvement (8.6% vs 18.9%, p=0.022) compared with patients with AS. Patients with AS exhibited worse spinal mobility and physical function compared with nr-axSpA. AS Disease Activity Scores and CRP levels were significantly higher in patients with AS compared with nr-axSpA (2.4 (IQR 1.7-2.8) vs 2.0 (IQR 1.1-2.3), p=0.022 and 7.1 (IQR 2.6-14.9) vs 2.5 (IQR 0.8-8.2) mg/L, p<0.001, respectively). CONCLUSIONS: Our data demonstrated some known and also novel differences between the two imaging arm fulfilling axSpA subgroups. Non-radiographic patients were mostly women who had experienced shorter disease duration, milder disease activity and better functional status with less hip involvement but more peripheral arthritis compared with patients with AS.

Metabolites of type I, II, III, and IV collagen may serve as markers of disease activity in axial spondyloarthritis.

Local inflammation in axial spondyloarthritis (axSpA) leads to the release of collagen metabolites from the disease-affected tissue. We investigated whether collagen metabolites were associated with disease activity and could distinguish non-radiographic(nr)-axSpA from ankylosing spondylitis (AS). A total of 193 axSpA patients (nr-axSpA, n = 121 and AS, n = 72) and asymptomatic controls (n = 100) were included. Serum levels of metalloproteinase (MMP)-degraded collagen type I (C1M), type II (C2M), type III (C3M) and type IV (C4M2) were quantified by enzyme-linked immunosorbent assay (ELISA). All metabolites were higher in axSpA than in controls (all p < 0.001). Serum levels of C1M, C3M, and C4M2 were increased in AS compared to nr-axSpA (43.4 ng/mL vs. 34.6; p < 0.001, 15.4 vs. 12.8; p = 0.001, and 27.8 vs. 22.4; p < 0.001). The best metabolite to differentiate between axSpA and controls was C3M (AUC 0.95; specificity 92.0, sensitivity 83.4). C1M correlated with ASDAS-CRP in nr-axSpA (ρ = 0.37; p < 0.001) and AS (ρ = 0.57; p < 0.001). C1M, C3M, and C4M2 were associated with ASDAS-CRP in AS and nr-axSpA after adjustment for age, gender, and disease duration. Serum levels of collagen metabolites were significantly higher in AS and nr-axSpA than in controls. Moreover, the present study indicates that collagen metabolites reflect disease activity and are useful biomarkers of axSpA.