Distinct immune modulatory roles of regulatory T cells in gut versus joint inflammation in TNF-driven spondyloarthritis

OBJECTIVES

Gut and joint inflammation commonly co-occur in spondyloarthritis (SpA) which strongly restricts therapeutic modalities. The immunobiology underlying differences between gut and joint immune regulation, however, is poorly understood. We therefore assessed the immunoregulatory role of CD4+FOXP3+ regulatory T (Treg) cells in a model of Crohn's-like ileitis and concomitant arthritis.

METHODS

RNA-sequencing and flow cytometry was performed on inflamed gut and joint samples and tissue-derived Tregs from tumour necrosis factor (TNF)∆ARE mice. In situ hybridisation of TNF and its receptors (TNFR) was applied to human SpA gut biopsies. Soluble TNFR (sTNFR) levels were measured in serum of mice and patients with SpA and controls. Treg function was explored by in vitro cocultures and in vivo by conditional Treg depletion.

RESULTS

Chronic TNF exposure induced several TNF superfamily (TNFSF) members (4-1BBL, TWEAK and TRAIL) in synovium and ileum in a site-specific manner. Elevated TNFR2 messenger RNA levels were noted in TNF∆ARE/+ mice leading to increased sTNFR2 release. Likewise, sTNFR2 levels were higher in patients with SpA with gut inflammation and distinct from inflammatory and healthy controls. Tregs accumulated at both gut and joints of TNF∆ARE mice, yet their TNFR2 expression and suppressive function was significantly lower in synovium versus ileum. In line herewith, synovial and intestinal Tregs displayed a distinct transcriptional profile with tissue-restricted TNFSF receptor and p38MAPK gene expression.

CONCLUSIONS

These data point to profound differences in immune-regulation between Crohn's ileitis and peripheral arthritis. Whereas Tregs control ileitis they fail to dampen joint inflammation. Synovial resident Tregs are particularly maladapted to chronic TNF exposure.

Systemic effects of IL-6 blockade in rheumatoid arthritis beyond the joints

Interleukin (IL)-6 is produced locally in response to an inflammatory stimulus, and is able to induce systemic manifestations at distance from the site of inflammation. Its unique signaling mechanism, including classical and trans-signaling pathways, leads to a major expansion in the number of cell types responding to IL-6. This pleiotropic cytokine is a key factor in the pathogenesis of rheumatoid arthritis (RA) and is involved in many extra-articular manifestations that accompany the disease. Thus, IL-6 blockade is associated with various biological effects beyond the joints. In this review, the systemic effects of IL-6 in RA comorbidities and the consequences of its blockade will be discussed, including anemia of chronic disease, cardiovascular risks, bone and muscle functions, and neuro-psychological manifestations.

Representativeness of Systemic Sclerosis Patients in Interventional Randomized Trials: an analysis of the EUSTAR database

OBJECTIVE

To estimate the extent of and the reasons for ineligibility in randomized controlled trials (RCTs) of systemic sclerosis (SSc) patients included in the EUSTAR database, and to determine the association between patient's features and generalizability of study results.

METHODS

We searched Clinicaltrials.gov for all records on interventional SSc-RCTs registered from January 2013 to January 2018. Two reviewers selected studies, and information on the main trial features were retrieved. Data from 8046 patients having a visit in the EUSTAR database since 2013 were used to check patient's eligibility. The proportion of potentially eligible patients per trial, and the risk factors for ineligibility were analyzed. Complete-, worst- and best-case analyses were performed.

RESULTS

Of the 37 RCTs included, 43% were conducted in Europe, 35% were industry-funded, and 87% investigated pharmacological treatments. Ninety-one percent of 8046 patients included could have participated in at least one RCT. In complete-case analysis, the median [range] proportion of eligible patients having the main organ complication targeted by each study was 60% [10-100] in the overall sample of trials, ranging from 50% [32-79] for trials on skin fibrosis to 90% [34-77] for those targeting Raynaud's phenomenon. Among the criteria checked, treatment- and safety-related but not demographic were the main barriers to patient's recruitment. Older age, absence of Raynaud's phenomenon, and lower mRSS were independently associated with the failure to fulfill criteria for any of the included studies.

CONCLUSIONS

Patient's representativeness in SSc-RCTs is highly variable and is driven more by treatment- and safety-related rather than demographic criteria.

Greater trochanteric pain syndrome: predicting who will respond to a local glucocorticoid injection

Objectives: This study aimed to explore whether certain clinical tests or a rapid improvement in lateral hip pain following periarticular injection are predictive of subsequent efficacy of local glucocorticoid (GC) injection in greater trochanteric pain syndrome (GTPS).Method: This secondary analysis of a randomized controlled trial of an injection of GC and local anaesthetic (LA) versus placebo included 44 patients with GTPS. Two subgroups of patients were defined: (i) 30 min responders, reporting a decrease of ≥ 50% of the initial pain at 30 min post-injection; and (ii) positive triple test, presenting a combination of three positive clinical tests (30-second single-leg stance, FABER, and Lequesne). Median level of numeric rating scale for pain at 1 month was the primary outcome. Interaction analysis of treatment effect in the subgroups was performed using a linear regression adjusting for pain at baseline.Results: Sixteen patients (36%) were 30 min responders. In this group, GC treatment was associated with a significant improvement in pain at 1 month compared to non-responders (p = 0.03). The 30 min response was not associated with the use of LA. Positive triple test (22% of patients) was associated with higher pain scores at baseline (p = 0.03). In this group, patients who received placebo had significantly more pain at 1 month than those with the cortisone injection (p = 0.04).Conclusion: Patients with GTPS who present a rapid decrease in pain after periarticular injection, and those who display a combination of three specific clinical tests, are more likely to benefit from an injection with GC and anaesthetic.

Predictive value of anti-CarP and anti-PAD3 antibodies alone or in combination with RF and ACPA for the severity of rheumatoid arthritis

OBJECTIVES

The objective of this study was to analyse the predictive value of anti-carbamylated protein (anti-CarP) and anti-peptidyl-arginine deiminase type-3 (anti-PAD3) antibodies, alone or in combination with RF and ACPA, to identify patients at high risk of developing severe RA outcomes.

METHODS

Patients within the Swiss Clinical Quality Management registry with a biobank sample were tested for RF, ACPA, anti-CarP, and anti-PAD3 antibodies. We examined the association of each autoantibody with DAS28, HAQ and radiographic damage (Ratingen) at baseline and longitudinally.

RESULTS

Analyses included 851 established RA patients and 516 disease controls [axial spondyloarthritis (axSpA = 320) and PsA (196)]. Anti-CarP and anti-PAD3 antibodies were, respectively, present in 22.4% and 10.7% of the whole RA population, and in 13.2% and 3.8% of the RF and ACPA double seronegative patients. At baseline, RA patients with anti-PAD3 had higher DAS28 (4.2 vs 3.7; P= 0.005) and significantly more radiographic damage (14.9 vs 8.8; P= 0.02) than anti-PAD3-negative patients. In the ACPA-negative subgroup, baseline Ratingen scores were significantly higher in anti-PAD3-positive patients (P= 0.01). The combination of anti-PAD3, RF IgM, and ACPA was associated with significantly higher baseline radiographic scores than the double seropositive group (P= 0.04). The presence of any two of the previous autoantibodies was associated with significantly greater radiographic progression over 10 years than if all were absent (P= 0.02). There were no differences in RA outcome measures with regards to anti-CarP.

CONCLUSIONS

Anti-PAD3 antibodies are associated with higher disease activity and joint damage scores in RA patients.

Serum calprotectin: a promising biomarker in rheumatoid arthritis and axial spondyloarthritis

Background

Calprotectin (S100A8/S100A9 protein) is known as a damage-associated molecular pattern (DAMP) protein and reflects mainly neutrophil activation. Serum calprotectin levels might be a good alternative to acute-phase protein as a biomarker in inflammatory rheumatic diseases. The aim of this study is to investigate the association of serum calprotectin with disease activity and severity in rheumatoid arthritis (RA), axial spondyloarthritis (axSpA), and psoriatic arthritis (PsA).

Methods

Serum calprotectin was measured in patients with RA, axSpA, and PsA from the prospective Swiss Clinical Quality Management (SCQM) registry. Asymptomatic first-degree relatives of RA patients were used as healthy controls (HC). Outcomes included swollen joint count (SJC), Disease Activity Score (DAS), Health Assessment questionnaire (HAQ), joint radiographs, and ultrasound power Doppler (USPD) score for RA; Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS) and coxitis for axSpA; and SJC and Disease Activity Index for PSoriatic Arthritis (DAPSA) for PsA. Comparison of outcomes by calprotectin quartile levels was performed using Kruskal-Wallis tests for continuous outcomes or trend tests for categorical outcomes.

Results

A total of 1729 subjects [RA = 969, axSpA = 451, PsA = 237, and HC = 72] were included. Median levels of serum calprotectin were higher in each disease group compared to HC (p < 0.01). In RA patients, all clinical outcomes were statistically different between quartiles of serum calprotectin, indicating an association between calprotectin levels and higher disease activity (SJC, DAS, and USPD scores) and severity (joint radiographs and HAQ). In axSpA, an association between calprotectin levels and ASDAS score (p < 0.01) and prevalence of coxitis (p = 0.02) was observed. For PsA patients, SJC and DAPSA did not differ across calprotectin quartiles.

Conclusions

This large study supports the association of serum calprotectin levels with disease activity in both RA and axSpA, but not in PsA.