Relevance of circulating Semaphorin 4A for rheumatoid arthritis response to treatment.

The lack of validated tools to predict rheumatoid arthritis (RA) disease course warrants the development of new reliable biomarkers. Our aim was to evaluate the merit of circulating SEMA4A for the prediction of outcomes in patients with RA. In a first cohort of 101 consecutive RA patients followed up for 41 ± 15 months, increased baseline SEMA4A levels were identified as an independent predictor of treatment failure (hazard ratio, HR 2.71, 95% CI 1.14-6.43), defined by the occurrence of patient-reported flares and initiation or change of targeted therapy. The highest predictive value of treatment failure was obtained with the combination of increased circulating SEMA4A and/or Disease Activity Score (DAS) 28-CRP > 3.2 and/or active synovitis on doppler ultrasound (HR 10.42, 95% CI 1.41-76.94). In a second independent cohort of 40 consecutive RA patients who initiated new therapy because of insufficient disease control, baseline SEMA4A levels were significantly higher in patients who further experienced none or moderate response, and SEMA4A concentrations were markedly decreased in the group of patients with good clinical response as compared to non-responders. Circulating SEMA4A appears as an appealing biomarker in RA with ability to predict treatment failure, and with association with response to therapy.

Semaphorins: From Angiogenesis to Inflammation in Rheumatoid Arthritis.

OBJECTIVE: To study the potential role of semaphorins in the pathogenesis of rheumatoid arthritis (RA). METHODS: Microarray experiments were performed on Affymetrix GeneChip Human Exon 1.0 ST arrays in RA endothelial cells (ECs) and control ECs derived from circulating progenitors. Expression of class 3 and class 4 semaphorins and their receptors in the serum of RA patients and healthy controls was assessed by immunohistochemical analysis in synovial tissue and by enzyme-linked immunosorbent assay. RESULTS: Microarray analysis revealed differential expression of class 3 and class 4 semaphorins and their receptors in RA ECs. Semaphorin 4A (SEMA4A), plexin D1, and neuropilin 1 messenger RNA (mRNA) levels were markedly increased in RA ECs by 1.75-, 2.21-, and 1.68-fold, respectively. Stimulation with tumor necrosis factor (TNF) led to a 2-fold increase in SEMA4A mRNA levels in RA ECs, and deficient SEMA4A expression modified RA EC angiogenic properties. Class 3 and class 4 semaphorins as well as their receptors were overexpressed in RA synovial tissue. A respective 1.30-fold increase and 1.54-fold increase in SEMA4A and SEMA3E, as well as a 24% decrease in SEMA3A, was observed in the serum of RA patients. Serum levels of SEMA4A, SEMA4D, and SEMA3A correlated with levels of inflammation and proangiogenic markers. In 2 independent cohorts of patients with low disease activity or with RA in remission, the presence of SEMA4A identified patients with residual disease activity. CONCLUSION: Gene expression profiling of ECs identified class 3 and class 4 semaphorins as potential biomarkers and therapeutic candidates in RA, with confirmed overexpression in ECs, synovial vessels, and serum, and correlation with validated markers of inflammation and angiogenesis. Thus, semaphorins might be novel and appealing EC-derived inflammatory and proangiogenic targets in RA.

Disease Activity Score in 28 Joints Using GGT Permits a Dual Evaluation of Joint Activity and Cardiovascular Risk.

OBJECTIVE: To identify the factors potentially associated with serum gamma-glutamyltransferase (GGT) elevation in patients with rheumatoid arthritis (RA). METHODS: This is a cross-sectional monocentric study including RA patients over a 12-month period. Data on liver function, RA disease activity, and hepatotoxic and cardiovascular (CV) risk factors were systematically collected. To provide a simple tool to evaluate both joint disease activity and CV risk factors, we constructed the Disease Activity Score in 28 joints (DAS28)-GGT composite index by replacing erythrocyte sedimentation rate (ESR) with GGT. RESULTS: Among the 129 included patients, 32 (25%) had isolated GGT increase. GGT correlated with age, C-reactive protein (CRP) levels, and body weight and were significantly increased in patients with alcohol intake, type 2 diabetes mellitus, hypertension, dyslipidemia, and metabolic syndrome. GGT levels also gradually increased with the number of CV risk factors and correlated with the Framingham CV risk score. The composite index DAS28-GGT remained a reliable marker of RA disease activity and accurately detected patients with CV risk factors. Conversely to the DAS28 and the DAS28-CRP, the DAS28-GGT steadily increased according to the number of CV risk factors and had an increased diagnostic value compared to the DAS28 and DAS28-CRP for the presence of at least 2 CV risk factors and a Framingham CV risk score greater than 10%. CONCLUSION: GGT may be considered as a marker of systemic inflammation and CV risk in patients with RA. Based on these findings, we herein propose an original index, the DAS28-GGT, which is able to evaluate both joint disease activity and CV risk. This index will deserve further validation in prospective cohorts.