Olokizumab plus methotrexate: safety and efficacy over 106 weeks of treatment

OBJECTIVE

To report long-term safety and tolerability of olokizumab (OKZ) in combination with methotrexate (MTX) in subjects with active rheumatoid arthritis (RA), using pooled data from three randomised clinical trials (RCT) followed by open-label extension (OLE) study.

METHODS

Cumulative data from three phase 3 core trials and their OLE were analysed. Safety variables assessed included treatment-emergent adverse events (AEs), serious AEs (SAEs), AEs of special interest and laboratory results. Efficacy assessments included ACR20/50/70 responses, Disease Activity Score 28 (C-reactive protein) <3.2, CDAI remission and low disease activity (LDA), SDAI remission and LDA, HAQ-DI decrease of 0.22 unit and Boolean 2.0 remission.

RESULTS

A total of 2304 patients received OKZ in combination with MTX either once every 2 weeks or once every 4 weeks. Event rates per 100 patient-years in OKZ every 2 weeks and OKZ every 4 weeks, respectively, were 9.57 and 9.13 for SAEs; 2.95 and 2.34 for serious infections; 0.09 and 0.05 for gastrointestinal perforations; 0.58 and 0.83 for major adverse cardiovascular events; and 0.45 and 0.50 for malignancies. No increase in the rate of any AE was observed over 106 weeks of treatment. The evaluation of laboratory variables demonstrated the expected changes, like neutropenia, elevation of liver enzymes and blood lipids. Clinical response rates remained stable during the OLE.

CONCLUSION

The long-term safety and tolerability of OKZ in combination with MTX remained stable. The efficacy of OKZ was maintained through week 106. These findings support OKZ as a treatment option for patients with active RA.

The effect of rituximab on patient reported outcomes in the preclinical phase of rheumatoid arthritis: 2 year data from the PRAIRI study

OBJECTIVES

Early treatment of individuals at risk of developing rheumatoid arthritis (RA-risk) in the preclinical phase has the potential to positively impact both patients and society by preventing disease onset and improving patients' quality of life. The PRAIRI study was a randomised, double-blind, placebo-controlled trial with the B-cell depleting agent rituximab (RTX), which resulted in a significant delay of arthritis development of up to 12 months in seropositive RA-risk individuals. Here, we report our findings on patient-reported outcomes (PROs) in this study population.

METHODS

Seventy-eight RA-risk individuals were treated with one single dose of either placebo (PBO) or 1000 mg RTX plus 100 mg methylprednisolone (MP) and anti-histamines, regardless of treatment allocation, as co-medication. Data on quality of life were collected at baseline and 1, 4, 6, 12 and 24 months using established PRO questionnaires (visual analogue scale (VAS) pain, health assessment questionnaire disability index (HAQ-DI) score, EuroQol five dimension (EQ-5D) and both physical and mental component score of the 36-item short-form heath survey (SF-36)).

RESULTS

No significant changes in quality of life over a 2 year follow-up were observed in at-risk individuals treated with RTX compared to PBO given the PRO scores at 24 months (mean difference±SEM: HAQ score=0.07±0.16; EQ-5D=-0.02±0.05; VAS pain=11.11±7.40). Furthermore, no significant effect of treatment on perceived arthritis severity at the time of clinically manifest disease (arthritis) was found.

CONCLUSION

One single dose of RTX plus MP administered to RA-risk individuals does not have a meaningful and measurable positive effect on PROs after 2 years of follow-up and/or perceived disease severity at the time of arthritis development.

TRIAL REGISTRATION NUMBER

Trial registered at EU Clinical Trial Register, EudraCT Number: 2009-010955-29 (https://www.clinicaltrialsregister.eu/ctr-search/search?query=Prevention+of+RA+by+B+cell+directed+therapy).

Forefoot inflammation in recent-onset ACPA-positive and ACPA-negative RA: clinically similar, but different in underlying inflamed tissues

OBJECTIVES

Although joint swelling is traditionally interpreted as synovitis, recent imaging studies showed that there is also inflammation of tenosynovium and intermetatarsal bursae in the forefoot. We aimed to increase our understanding of differences and similarities regarding forefoot involvement between ACPA-positive and ACPA-negative rheumatoid arthritis (RA) at diagnosis. Therefore, we (1) compared metatarsophalangeal (MTP) joint counts, walking disabilities and inflamed tissues between ACPA groups and (2) studied associations of joint swelling/tenderness and walking disabilities with underlying inflamed tissues within ACPA groups.

METHODS

171 ACPA-positive and 203 ACPA-negative consecutively diagnosed patients with RA had a physical joint examination (swollen joint count-66/tender joint count-68), filled a Health Assessment Questionnaire including the domain walking and underwent MRI of the MTP joints at diagnosis. Synovitis, tenosynovitis, osteitis and intermetatarsal bursitis (IMB) were assessed. Findings in age-matched healthy controls were applied to define abnormalities on MRI.

RESULTS

While ACPA-negative RA patients had more swollen joints (mean SJC 8 vs 6 in ACPA-positives, p=0.003), the number of swollen MTP joints was similar (mean 1 in both groups); walking disabilities were also equally common (49% vs 53%). In contrast, inflamed tissues were all more prevalent in ACPA-positive compared with ACPA-negative RA. Within ACPA-positive RA, IMB was associated independently with MTP-joint swelling (OR 2.6, 95% CI 1.4 to 5.0) and tenderness (OR 3.0, 95% CI 1.8 to 5.0). While in ACPA-negatives, synovitis was associated independently with MTP-joint swelling (OR 2.8, 95% CI 1.4 to 5.8) and tenderness (OR 2.5, 95% CI 1.3 to 4.8). Tenosynovitis contributed most to walking disabilities.

CONCLUSIONS

Although the forefoot of ACPA-positives and ACPA-negatives share clinical similarities at diagnosis, there are differences in underlying inflamed tissues. This reinforces that ACPA-positive and ACPA-negative RA are different entities.

Exploring the effect on primary endpoints in trials testing targeted therapy interventions for rheumatoid arthritis: a meta-epidemiological study on the appropriate use of a core outcome set

OBJECTIVES

To explore which core domain is best associated with the American College of Rheumatology (ACR) 20% response in trials assessing the effect of targeted interventions in rheumatoid arthritis (RA).

METHODS

A meta-epidemiological study was performed on randomised trials investigating biologics and targeted agents compared with placebo or conventional disease-modifying antirheumatic drugs in patients with RA. The main outcome measures were ORs for the ACR 20% response and at least one of the eight core domains according to the existing RA core outcome set (COS) analysed based on standardised mean differences.

RESULTS

115 trials involving 55 422 patients with RA were eligible. The OR for achieving ACR 20% response was 3.19 (95% CI 2.96 to 3.44) for the experimental interventions relative to the comparators. The median number of COS domains reported was 6; 18 trials reported only 1 domain, 17 all 8. Univariable meta-regression analyses indicated that each of the eight core domains was significantly associated with ACR 20% response, yet improvements in physical disability explain a successful ACR 20% response the most. Including only trials reporting on all eight core domains, univariable meta-regression analyses proved improvement in fatigue to explain a successful ACR 20% response the most.

CONCLUSIONS

Within this dataset, it is evident that the conclusions concerning our primary objective were significantly influenced by both the amount and characteristics of missing data. Our data suggest that fatigue could be more important for the primary endpoint than previously assumed, but this is based on limited data.

On difficulties to define prognostic factors for clinical practice in rheumatoid arthritis

In rheumatoid arthritis (RA), the identification of prognostic factors (PF) capable of predicting disease outcome, response to treatment or success of dose reduction is an important issue, as these factors are intended to serve as a basis for decision-making. The task is complex from the outset, as the definition of disease prognosis or therapeutic prognosis is not uniquevocal. The heterogeneity of the definitions used partly explains the failure to identify PF that can be applied at an individual level. But other factors also contribute. First, the scope of the disease studied is too broad, including nosologically different entities. Second, potential PF are only measured at a single point of time, whereas changes over a period of time should be taken into account to a greater extent, not forgetting the potential impact of the treatment received during this period. Beyond these limiting factors, one of the main obstacles to the identification of PF is probably the fact that the phase of the disease is not sufficiently taken into account. Predicting the disease outcome when it is well established is a more complex challenge than when it is just beginning, as many factors are likely to interfere. The same applies to therapeutic PF, which should be determined according to disease duration. Difficulties also arise from the approaches used, which are often restricted to a single field of interest whereas they should be much more integrative and call on new large-scale data analysis tools with a view to precision medicine.In RA, prognosis can be defined at two levels: disease outcome, including joint damage and risk of extra-articular manifestations and/or complications, and treatment outcome, including response to therapy, risk of adverse effects and drug-free remission.

Therapeutic interception in individuals at risk of rheumatoid arthritis to prevent clinically impactful disease

Multiple clinical trials for rheumatoid arthritis (RA) prevention have been completed. Here, we set out to report on the lessons learnt from these studies. Researchers who conducted RA prevention trials shared the background, rationale, approach and outcomes and evaluated the lessons learnt to inform the next generation of RA prevention trials. Individuals at risk of RA can be identified through population screening, referrals to musculoskeletal programmes and by recognition of arthralgia suspicious for RA. Clinical trials in individuals at risk for future clinical RA have demonstrated that limited courses of corticosteroids, atorvastatin and hydroxychloroquine do not alter incidence rates of clinical RA; however, rituximab delays clinical RA onset, and methotrexate has transient effects in individuals who are anticitrullinated protein antibody-positive with subclinical joint inflammation identified by imaging. Abatacept delays clinical RA onset but does not fully prevent onset of RA after treatment cessation. Additionally, subclinical joint inflammation and symptoms appear responsive to interventions such as methotrexate and abatacept. To advance prevention, next steps include building networks of individuals at risk for RA, to improve risk stratification for future RA and to understand the biological mechanisms of RA development, including potential endotypes of disease, which can be targeted for prevention, thus adopting a more precision-based approach. Future trials should focus on interceptions aimed at preventing clinical RA onset and which treat existing symptoms and imaging-defined subclinical inflammation. These trials may include advanced designs (eg, adaptive) and should be combined with mechanistic studies to further define pathophysiological drivers of disease development.

Persistence of power Doppler ultrasonography-detected synovitis over 1 year of follow-up predicts poor prognosis in rheumatoid arthritis in clinical remission: the SONORE prospective longitudinal study

OBJECTIVES

(1) To assess the progression of ultrasonography-detected synovitis in a cohort of patients with rheumatoid arthritis (RA) in remission during 1 year of follow-up (2) to evaluate the ability of consecutive examinations of ultrasonography to predict relapse (R) or radiographic progression (RP) at 1 year.

METHODS

Patients with RA (2010 American College of Rheumatology-European Alliance of Associations for Rheumatology criteria) in clinical remission (Disease Activity Score in 28 joints (DAS28)<2.6 without clinically active synovitis) were included. An independent investigator performed ultrasonography every 3 months for 1 year. Ultrasonography-detected synovitis was defined as power Doppler-positive ultrasonography synovitis (PDUS) grade ≥1 in at least one joint. PDUS at ≥2 consecutive visits during the follow-up defined persistent PDUS. An increase of ≥1 point in the modified total Sharp score defined RP. An increase in DAS28-C-reactive protein (CRP)>0.6 or DAS28-CRP>3.2 and any modification of disease-modifying anti-rheumatic drugs or glucocorticoids defined relapse. Univariate and multivariate Cox regression analyses were used to evaluate factors associated with R/RP at 1 year.

RESULTS

PDUS was detected in 75 (65.2%), 66, 60, 46 and 29 of the 115 patients with RA at baseline and at months 3, 6, 9 and 12, respectively. 58 (50.4%) patients exhibited persistent PDUS. After 1 year, 22/85 (25.9%) experienced relapse and 12 (14.1%) showed RP. On multivariate analysis, factors predicting R/RP at 1 year were persistent PDUS (HR=2.98, p=0.014) and an increase in DAS28-CRP level at the visit before relapse (HR=4.36, p=0.004).

CONCLUSION

Persistent PDUS during follow-up, rather than at baseline, predicted worse outcome at 1 year and requires careful monitoring.

Agreement between patient-reported flares and clinically significant flare status in patients with rheumatoid arthritis in sustained remission: data from the ARCTIC REWIND trials

OBJECTIVES

To explore the agreement between patient-reported flare status and clinically significant flare status in patients with rheumatoid arthritis (RA) in sustained remission.

METHOD

Patients with RA in remission for ≥12 months on stable treatment were included in the ARCTIC REWIND tapering trials and pooled 12-month data used in current analyses. Patient-reported flare status was assessed according to the Outcome Measures in Rheumatology flare questionnaire; 'Are you having a flare of your RA at this time?' (yes/no). A clinically significant flare was defined as a combination of Disease Activity Score (DAS) >1.6, increase in DAS of ≥0.6 and 2 swollen joints, or the rheumatologist and patient agreed that a clinically significant flare had occurred. Agreement coefficient, sensitivity, specificity and predictive values of patient-reported flare status with regard to clinically significant flare status were determined.

RESULTS

Of 248 patients, 64% were women, age 56.1 (11.8) years, disease duration 4.1 (2.8-7.4) years, DAS 0.8 (0.3). 35% of patients reported a flare at least once, clinically significant flares were recorded in 21%. 48/53 clinically significant flares (91%) led to an intensification of disease-modifying antirheumatic drugss. In 621/682 (91%) visits, patient-reported and clinically significant flare status were in agreement, agreement coefficient 0.89. Sensitivity and specificity were both 91%, positive predictive value of patient-reported flare status 46% and negative predictive value 99%.

CONCLUSION

Among patients in sustained remission, patient-reported flare status was accurate in ruling out a clinically significant flare. About half of the patient-reported flares were assessed to be clinically significant. These findings support a potential for using patient-reported flare status in remote monitoring of patients with RA in sustained remission.

How to Approach the Imaging Differential Diagnosis of Rheumatic Diseases by Anatomic Location

The purpose of this review is to present an approach to differential diagnosis based on the particular features of involvement of the most common rheumatological conditions focused on anatomic location (by joint). The most common radiological signs and how they are demonstrated in different modalities, as well as the typical patterns of involvement are analyzed, with the aim to facilitate the differential diagnosis. Early and adequate adjustment of treatment has an effect on outcome, and on this basis, early diagnosis and characterization are paramount to appropiately manage patients.

Integrated safety analysis of filgotinib in patients with moderate-to-severe rheumatoid arthritis over a treatment duration of up to 8.3 years

OBJECTIVES

To update the long-term safety profile of filgotinib, a Janus kinase-1 preferential inhibitor, in patients with moderate-to-severe rheumatoid arthritis.

METHODS

Data from seven trials were integrated (NCT01888874, NCT01894516, NCT02889796, NCT02873936, NCT02886728, NCT02065700 and NCT03025308). Patients received once-daily filgotinib 100 mg or 200 mg. Exposure-adjusted incidence rates (EAIRs)/100 patient-years of exposure (PYE) were calculated for treatment-emergent adverse events (TEAEs). Post hoc analyses assessed patients aged <65 and ≥65 years.

RESULTS

Patients (N=3691) received filgotinib for a median (maximum) of 3.8 (8.3) years (12 541 PYE). Rates of TEAEs of interest: serious infections, malignancies, major adverse cardiovascular events (MACE) and venous thromboembolism were stable over time and comparable between doses. In the overall population, numerically lower EAIR (95% CI)/100 PYE of herpes zoster was observed for filgotinib 100 mg versus 200 mg (1.1 (0.8 to 1.5) vs 1.5 (1.2 to 1.8)). Incidence of serious infections, herpes zoster, MACE, malignancies and all-cause mortality was higher in patients aged ≥65 versus <65 years. In patients aged ≥65 years, EAIRs (95% CI)/100 PYE for non-melanoma skin cancer (NMSC) (0.4 (0.1 to 1.1) vs 1.4 (0.8 to 2.2)), malignancies excluding NMSC (1.0 (0.5 to 1.9) vs 2.0 (1.3 to 2.9)) and all-cause mortality (1.3 (0.7 to 2.2) vs 1.6 (1.0 to 2.5)) were numerically lower for filgotinib 100 mg versus 200 mg.

CONCLUSIONS

In the overall population, TEAEs of interest were stable over time and similar between filgotinib 100 mg and 200 mg dose groups, except for herpes zoster. A dose-dependent relationship between malignancies and all-cause mortality was suggested in patients ≥65 years old.

NAT10 promotes synovial aggression by increasing the stability and translation of N4-acetylated PTX3 mRNA in rheumatoid arthritis

OBJECTIVE

Recent studies indicate that N-acetyltransferase 10 (NAT10)-mediated ac4C modification plays unique roles in tumour metastasis and immune infiltration. This study aimed to uncover the role of NAT10-mediated ac4C in fibroblast-like synoviocytes (FLSs) functions and synovial immune cell infiltration in rheumatoid arthritis (RA).

METHODS

FLSs were obtained from active established patients with RA. Protein expression was determined by western blotting or immunohistochemistry or multiplexed immunohistochemistry. Cell migration was measured using a Boyden chamber. ac4C-RIP-seq combined with RNA-seq was performed to identify potential targets of NAT10. RNA immunoprecipitation was used to validate the interaction between protein and mRNA. NAT10 haploinsufficiency, inhibitor remodelin or intra-articular Adv-NAT10 was used to suppress arthritis in mice with delayed-type hypersensitivity arthritis (DYHA) and collagen II-induced arthritis (CIA) and rats with CIA.

RESULTS

We found elevated levels of NAT10 and ac4C in FLSs and synovium from patients with RA. NAT10 knockdown or specific inhibitor treatment reduced the migration and invasion of RA FLSs. Increased NAT10 level in the synovium was positively correlated with synovial infiltration of multiple types of immune cells. NAT10 inhibition in vivo attenuated the severity of arthritis in mice with CIA and DTHA, and rats with CIA. Mechanistically, we explored that NAT10 regulated RA FLS functions by promoting stability and translation efficiency of N4-acetylated PTX3 mRNA. PTX3 also regulated RA FLS aggression and is associated with synovial immune cell infiltration.

CONCLUSION

Our findings uncover the important roles of NAT10-mediated ac4C modification in promoting rheumatoid synovial aggression and inflammation, indicating that NAT10 may be a potential target for the treatment of RA, even other dysregulated FLSs-associated disorders.

Janus kinase inhibitors and tumour necrosis factor inhibitors show a favourable safety profile and similar persistence in rheumatoid arthritis, psoriatic arthritis and spondyloarthritis: real-world data from the BIOBADASER registry

OBJECTIVES

To compare the safety of Janus kinase inhibitors (JAKi) with that of tumour necrosis factor inhibitors (TNFi) and determine drug persistence among patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA).

METHODS

We analysed data from patients included in BIOBADASER 3.0 and treated with JAKi or TNFi from 2015 to 2023 and estimated the incidence rate ratio (IRR) of adverse events and persistence.

RESULTS

A total of 6826 patients were included. Of these, 52% had RA, 25% psoriatic arthritis and 23% axial SpA. Treatment was with TNFi in 86%. The mean duration of treatment was 2.2±2.0 years with TNFi versus 1.8±1.5 with JAKi. JAKis were prescribed in older patients with longer term disease, greater comorbidity and later treatment lines and more frequently as monotherapy. The IRR of all infections and gastrointestinal events was higher among patients with RA treated with JAKi. Drug persistence at 1, 2 and 3 years was 69%, 55% and 45% for TNFi and 68%, 54% and 45% for JAKi. Multivariate regression models showed a lower probability of discontinuation for JAKi (HR=0.85; 95% CI 0.78-0.92) and concomitant conventional synthetic disease-modifying antirheumatic drugs (HR=0.90; 95% CI 0.84-0.96). The risk of discontinuation increased with glucocorticoids, comorbidities, greater disease activity and later treatment lines.

CONCLUSIONS

Infections, herpes zoster and gastrointestinal adverse events in patients with RA tended to be more frequent with JAKi. However, prognosis was poor in patients receiving JAKi. Persistence was similar for TNFi and JAKi, although factors associated with discontinuation differed by diagnostic group.

Disease activity of rheumatoid arthritis and kidney function decline: a large prospective registry study

INTRODUCTION

Chronic kidney disease (CKD) is a common comorbidity of rheumatoid arthritis (RA). The association of longitudinal RA disease activity with long-term kidney function has remained uncertain.

METHOD

We analysed a multicentre prospective RA registry in the USA from 2001 to 2022. The exposure was updated time-averaged Clinical Disease Activity Index (TA-CDAI) categories from study enrolment. The primary outcome was a longitudinal estimated glomerular filtration rate (eGFR) change. Secondary outcomes included developments of CKD stage G3a (eGFR<60 mL/min/1.73 m2) and stage G3b (eGFR<45 mL/min/1.73 m2). Results were adjusted for relevant time-fixed and time-varying covariates.

RESULTS

31 129 patients (median age: 58.0 years, female: 76.3%, median eGFR: 90.7 mL/min/1.73 m2) contributed 234 973 visits and 146 778 person-years of follow-up. Multivariable mixed-effect linear model showed an average annual eGFR decline during follow-up in the TA-CDAI-remission group of -0.83 mL/min/1.73 m2 and estimated additional annual declines (95% CI) of -0.09 (-0.15 to -0.03) in low, -0.17 (-0.23 to -0.10) in moderate and -0.18 (-0.27 to -0.08) mL/min/1.73 m2 in high disease activity patients. Compared with TA-CDAI remission, adjusted HRs (95% CI) for CKD stage G3a during follow-up were 1.15 (1.01 to 1.30) in low, 1.22 (1.06 to 1.40) in moderate and 1.27 (1.05 to 1.52) in high disease activity; for CKD stage G3b, 1.22 (0.84 to 1.76) in low, 1.66 (1.12 to 2.45) in moderate and 1.93 (1.16 to 3.20) in high disease activity.

CONCLUSIONS

Higher RA disease activity was associated with accelerated eGFR decline and increased risk of clinically relevant kidney dysfunction. Future intervention studies should attempt to replicate the association between RA disease activity and eGFR.

Positive feedback loop PU.1-IL9 in Th9 promotes rheumatoid arthritis development

OBJECTIVES

T helper 9 (Th9) cells are recognised for their characteristic expression of the transcription factor PU.1 and production of interleukin-9 (IL-9), which has been implicated in various autoimmune diseases. However, its precise relationship with rheumatoid arthritis (RA) pathogenesis needs to be further clarified.

METHODS

The expression levels of PU.1 and IL-9 in patients with RA were determined by ELISA, western blotting (WB) and immunohistochemical staining. PU.1-T cell-conditional knockout (KO) mice, IL-9 KO and IL-9R KO mice were used to establish collagen antibody-induced arthritis (CAIA), respectively. The inhibitor of PU.1 and IL-9 blocking antibody was used in collagen-induced arthritis (CIA). In an in vitro study, the effects of IL-9 were investigated using siRNAs and IL-9 recombinant proteins. Finally, the underlying mechanisms were further investigated by luciferase reporter analysis, WB and Chip-qPCR.

RESULTS

The upregulation of IL-9 expression in patients with RA exhibited a positive correlation with clinical markers. Using CAIA and CIA model, we demonstrated that interventions targeting PU.1 and IL-9 substantially mitigated the inflammatory phenotype. Furthermore, in vitro assays provided the proinflammatory role of IL-9, particularly in the hyperactivation of macrophages and fibroblast-like synoviocytes. Mechanistically, we uncovered that PU.1 and IL-9 form a positive feedback loop in RA: (1) PU.1 directly binds to the IL-9 promoter, activating its transcription and (2) Th9-derived IL-9 induces PU.1 via the IL-9R-JAK1/STAT3 pathway.

CONCLUSIONS

These results support that the PU.1-IL-9 axis forms a positive loop in Th9 dysregulation of RA. Targeting this signalling axis presents a potential target approach for treating RA.

Journey through discovery of 75 years glucocorticoids: evolution of our knowledge of glucocorticoid receptor mechanisms in rheumatic diseases

For three-quarters of a century, glucocorticoids (GCs) have been used to treat rheumatic and autoimmune diseases. Over these 75 years, our understanding of GCs binding to nuclear receptors, mainly the glucocorticoid receptor (GR) and their molecular mechanisms has changed dramatically. Initially, in the late 1950s, GCs were considered important regulators of energy metabolism. By the 1970s/1980s, they were characterised as ligands for hormone-inducible transcription factors that regulate many aspects of cell biology and physiology. More recently, their impact on cellular metabolism has been rediscovered. Our understanding of cell-type-specific GC actions and the crosstalk between various immune and stromal cells in arthritis models has evolved by investigating conditional GR mutant mice using the Cre/LoxP system. A major achievement in studying the complex, cell-type-specific interplay is the recent advent of omics technologies at single-cell resolution, which will provide further unprecedented insights into the cell types and factors mediating GC responses. Alongside gene-encoded factors, anti-inflammatory metabolites that participate in resolving inflammation by GCs during arthritis are just being uncovered. The translation of this knowledge into therapeutic concepts will help tackle inflammatory diseases and reduce side effects. In this review, we describe major milestones in preclinical research that led to our current understanding of GC and GR action 75 years after the first use of GCs in arthritis.

Helicobacter pylori upregulates PAD4 expression via stabilising HIF-1α to exacerbate rheumatoid arthritis

OBJECTIVE

Helicobacter pylori infection has been reported to aggravate rheumatoid arthritis (RA), but the relevant mechanism remains unclear. This study aimed to investigate the underlying pathogenic mechanism of H. pylori infection in the progression of RA.

METHODS

The Disease Activity Score (DAS-28) and serum anticitrullinated protein antibody (ACPA) levels were compared between H. pylori-negative and H. pylori-positive patients with RA. MH7A cells were stimulated with polyclonal ACPA purified from the peripheral blood of patients with RA. The citrullination levels were assessed by western blot in GES-1 cells and sera. ChIP, luciferase reporter assays, mass spectrometry and ELISA were applied to explore the molecular mechanism of H. pylori infection in RA progression.

RESULTS

The DAS-28 and ACPA levels of patients with RA in the H. pylori-positive group were significantly higher than those in the H. pylori-negative group. Polyclonal ACPA derived from H. pylori-positive patients promoted cell proliferation and induced secretion of IL-6 and IL-8. For the first time, we found that H. pylori infection induces cellular protein citrullination by upregulating protein arginine deiminase type 4 (PAD4). Furthermore, we confirmed a direct functional binding of hypoxia-inducible factor 1α on the PADI4 gene promoter. We demonstrated that PAD4 interacts with and citrullinates keratin 1 (K1), and serum and synovial fluid levels of anti-Cit-K1 antibody were markedly increased in H. pylori-infected patients with RA.

CONCLUSION

Our findings reveal a novel mechanism by which H. pylori infection contributes to RA progression. Therapeutic interventions targeting H. pylori may be a viable strategy for the management of RA.

Biological use influences the impact of inflammation on risk of major adverse cardiovascular events in rheumatoid arthritis

OBJECTIVES

Chronic inflammation promotes cardiovascular risk in rheumatoid arthritis (RA). Biological disease-modifying antirheumatic drugs (bDMARDs) improve disease activity and cardiovascular disease outcomes. We explored whether bDMARDs influence the impact of disease activity and inflammatory markers on long-term cardiovascular risk in RA.

METHODS

We studied 4370 participants without cardiovascular disease in a 10-country observational cohort of patients with RA. Endpoints were (1) major adverse cardiovascular events (MACE) encompassing myocardial infarction, stroke and cardiovascular death; and (2) any ischaemic cardiovascular events (iCVE) including MACE plus revascularisation, angina, transient ischaemic attack and peripheral arterial disease.

RESULTS

Over 26 534 patient-years, 239 MACE and 362 iCVE occurred. The interaction between 28-joint Disease Activity Score with C-reactive protein (DAS28-CRP) and bDMARD use was significant for MACE (p=0.017), suggesting the effect of DAS28-CRP on MACE risk differed among bDMARD users (n=515) and non-users (n=3855). DAS28-CRP (per unit increase) is associated with MACE risk in bDMARD non-users (HR 1.21 (95% CI 1.07 to 1.37)) but not users (HR 0.69 (95% CI 0.40 to 1.20)). The interaction between CRP (per log unit increase) and bDMARD use was also significant for MACE (p=0.011). CRP associated with MACE risk in bDMARD non-users (HR 1.16 (95% CI 1.04 to 1.30)), but not users (HR 0.65 (95% CI 0.36 to 1.17)). No interaction was observed between bDMARD use and DAS28-CRP (p=0.167) or CRP (p=0.237) for iCVE risk.

CONCLUSIONS

RA activity and inflammatory markers associated with risk of MACE in bDMARD non-users but not users suggesting the possibility of biological-specific benefits locally on arterial wall independently of effects on systemic inflammation.

Acetylated bacterial proteins as potent antigens inducing an anti-modified protein antibody response

OBJECTIVE

Gut-residing bacteria, such as Escherichia coli, can acetylate their proteome under conditions of amine starvation. It is postulated that the (gut) microbiome is involved in the breach of immune tolerance to modified self-proteins leading to the anti-modified protein antibodies (AMPAs), hallmarking seropositive rheumatoid arthritis (RA). Our aim was to determine whether acetylated bacterial proteins can induce AMPA responses cross-reactive to modified self-proteins and be recognised by human AMPA (hAMPA).

METHODS

E. coli bacteria were grown under amine starvation to generate endogenously acetylated bacterial proteins. Furthermore, E. coli proteins were acetylated chemically. Recognition of these proteins by hAMPA was analysed by western blotting and ELISA; recognition by B cells carrying a modified protein-reactive B cell receptor (BCR) was analysed by pSyk (Syk phosphorylation) activation assay. C57BL/6 mice were immunised with (modified) bacterial protein fractions, and sera were analysed by ELISA.

RESULTS

Chemically modified bacterial protein fractions contained high levels of acetylated proteins and were readily recognised by hAMPA and able to activate B cells carrying modified protein-reactive BCRs. Likely due to substantially lower levels of acetylation, endogenously acetylated protein fractions were not recognised by hAMPA or hAMPA-expressing B cells. Immunising mice with chemically modified protein fractions induced a strong cross-reactive AMPA response, targeting various modified antigens including citrullinated proteins.

CONCLUSIONS

Acetylated bacterial proteins are recognisable by hAMPA and are capable of inducing cross-reactive AMPA in mice. These observations provide the first conceptual evidence for a novel mechanism involving the (endogenous) acetylation of the bacterial proteome, allowing a breach of tolerance to modified proteins and the formation of cross-reactive AMPA.

Expression of HIF1α in intestinal epithelium restricts arthritis inflammation by inhibiting RIPK3-induced cell death machinery

OBJECTIVES

To investigate the mechanism by which intestinal epithelial cell (IEC) death induces arthritis.

METHODS

IEC death was assessed by staining for necroptosis and apoptosis markers and fluorescence in situ hybridisation at different time points during collagen-induced arthritis (CIA). During the development of CIA, messenger RNA (mRNA) sequencing was performed, followed by Gene Ontology enrichment analysis of differentially expressed genes. Mice deficient for hypoxia-inducible factor 1α (Hif1a) in IECs (Hif1a ∆IEC) were generated and induced for arthritis. mRNA sequencing, chromatin immunoprecipitated (ChIP) DNA sequencing and ChIP-qualitative PCR were performed on IECs from Hif1a ∆IEC mice and littermate controls. Effects of HIF1α stabilisation by inhibition of prolyl hydroxylase domain-containing enzymes and treatment with the inhibitor of receptor-interacting protein kinase-3 (RIPK3) were tested in intestinal organoids and in CIA.

RESULTS

IEC underwent apoptotic and necroptotic cell death at the onset of arthritis, leading to impaired gut barrier function. HIF1α was identified as one of the most upregulated genes in IECs during the onset of arthritis. Deletion of Hif1a in IEC enhanced IEC necroptosis, triggered intestinal inflammation and exacerbated arthritis. HIF1α was found to be a key transcriptional repressor for the necroptosis-inducing factor RIPK3. Enhanced RIPK3 expression, indicating necroptosis, was also found in the intestinal epithelium of patients with new-onset rheumatoid arthritis. Therapeutic stabilisation of HIF1α as well as small-molecule-based RIPK3 inhibition rescued intestinal necroptosis in vitro and in vivo and suppressed the development of arthritis.

CONCLUSION

Our results identify IEC necroptosis as a critical link between the gut and the development of arthritis.