Impairment in work and activities of daily life in patients with psoriasis: results of the prospective BioCAPTURE registry

Background: Little is known about the extent of impairments in work and activities of daily life (ADL) in patients with psoriasis, and the influence of contextual factors such as disease-related characteristics and treatment. Therefore, this study aimed to assess these impairments in patients with psoriasis who started using biologicals/small molecule inhibitors.Methods: Using data from the prospective BioCAPTURE registry, we collected patient, disease, and treatment parameters, as well as work/ADL impairments at baseline, 6 and 12 months. Changes in impairment parameters and correlations between impairment and patient/disease characteristics were assessed using generalized estimating equations.Results: We included 194 patients in our analysis. After biological initiation, disease activity decreased significantly (PASI 11.2 at baseline versus 3.9 at 12 months, p < 0.001). Work-for-pay in this cohort was lower than in the Dutch general population (53% versus 67%, p = 0.01). In patients who had work-for-pay, presenteeism improved over time (5% at baseline versus 0% at 12 months, p = 0.04). Up to half of the patients reported impairments in ADL, which did not change over time. Associations between impairments and contextual factors varied, but all impairments were associated with worse mental/physical general functioning.Conclusion: Patients with psoriasis using biologicals are less likely to have work-for-pay. Treatment improves the work productivity of employed patients, but we were unable to detect changes in ADL performance.

Development of a New Referral Tool to Identify Psoriasis Patients with Concomitant Psoriatic Arthritis: Results of the Prospective DAPPER Cohort

Patients with psoriasis are at risk of developing psoriatic arthritis, which can lead to joint damage. While screening questionnaires have been developed, their performance varies. The objective of this study was to develop a referral tool for dermatologists to identify psoriasis patients with concomitant psoriatic arthritis for rheumatological referral. This study used data from the DAPPER study, in which psoriasis patients were screened by a rheumatologist for the presence of concomitant psoriatic arthritis. Multivariable regression analysis was used to identify predictive variables for the presence of concomitant psoriatic arthritis: treatment history with conventional systemic drugs (odds ratio (OR) 2.97, 95% confidence interval (95% CI) 1.01-8.74, p = 0.04), treatment history with biologicals/small molecule inhibitors (OR 2.90, 95% CI 1.52-5.53, p = 0.01), patient-reported history of joint pain not caused by trauma (OR 4.23, 95% CI 1.21-14.79, p = 0.01), patient-reported history of swollen joints (OR 4.25, 95% CI 2.17-8.32, p < 0.001), and patient-reported history of sausage-like swollen digits (OR 2.38, 95% CI 1.25-4.55, p = 0.01). Based on these variables, a referral tool was created with an area under the curve of 0.82. This referral tool could be used to aid dermatologists to identify psoriasis patients with concomitant psoriatic arthritis, who may benefit from rheumatological referral.

Discovery of Psoriatic Arthritis in Psoriasis Patients for Early Rheumatological Referral (DAPPER) Study: A Prospective Observational Cohort

Patients with psoriasis are at risk of developing psoriatic arthritis, which can lead to irreversible joint damage. However, a proportion of patients with psoriasis and concomitant psoriatic arthritis remain undiscovered in practice. The aims of this study were: to prospectively determine prevalence, characteristics, and disease burden of psoriatic arthritis in a psoriasis population; and to determine the prevalence and characteristics of patients with active psoriatic arthritis, who were not under rheumatological care. Patients with psoriasis were screened by a rheumatologist at the dermatology outpatient clinic for psoriatic arthritis. Patients with suspected active psoriatic arthritis who were not seeing a rheumatologist were referred to a rheumatologist for confirmation. The total prevalence of psoriatic arthritis in this observational, prospective cohort (n = 303) was 24%. Patients with psoriasis with concomitant psoriatic arthritis had longer duration of skin disease and more often a treatment history with systemic therapies. In this academic, specialized, setting, 2.3% of patients (n = 7), were not receiving rheumatological care despite having active psoriatic arthritis. These patients were characterized by a combination of low (perceived) disease burden and low yield of screening questionnaires, making it difficult for dermatologists to discover psoriatic arthritis in these patients. Thus, screening for more subtle active arthritis in patients with psoriasis in a dermatology setting could be improved.

Determinants of work and social participation in patients with psoriatic arthritis in the Netherlands: an observational study

BACKGROUND

Psoriatic arthritis can cause pain, disability, and permanent joint damage. This can lead to impairments in work and social participation. Little is known about the extent of these impairments in routine practice. With this study, we aim to examine the extent of work and activity impairment in (subgroups of) Dutch patients with psoriatic arthritis (PsA), and to examine determinants associated with this impairment.

METHODS

This is an observational study using data collected from the electronic health records of PsA patients treated at the Sint Maartenskliniek, the Netherlands. Data about work and activity impairment were collected via the Work Productivity and Activity Impairment questionnaire. To compare our PsA-cohort with the Dutch general population, we used age- and sex-matched data derived from the Central Bureau of Statistics. Regression analyses were performed to examine determinants of work and activity impairment.

RESULTS

In total, 246 patients were included, of which 126 (51.2%) were female. Mean age (S.D.) was 55.7 (13.2) years. Compared with the Dutch general population, work for pay (WFP) was significantly lower in PsA (52.9% versus 62.6%, P < 0.001). In PsA, younger age and better physical function were associated with WFP status (P < 0.05). Higher disease activity, worse physical function, and worse mental health-related quality of life were associated with both more work and activity impairment (P < 0.05). Furthermore, reaching low disease activity status (LDA) according to Psoriatic ArthritiS Disease Activity Score (PASDAS; ≤ 3.2) was associated with less work and activity impairment than reaching LDA according to DAS28-CRP (≤ 2.9) (P < 0.05).

CONCLUSIONS

In PsA patients, worse physical function was associated with a lower likelihood of having WFP, and higher work and activity impairment. PASDAS LDA as a goal for treat to target, compared to DAS28-CRP, appears to favour the reduction of work and activity impairment.

Defining the minimal important change (MIC) and meaningful change value (MCV) of the Psoriatic Arthritis Disease Activity Score (PASDAS) in a routine practice cohort of Psoriatic Arthritis patients

OBJECTIVE

To determine the Minimal Important Change (MIC) values and Meaningful Change Values (MCV) of the Psoriatic Arthritis Disease Activity Score (PASDAS) and the Standard Error of Measurement (SEM) of the PASDAS.

METHODS

Routine practice data of 544 patients with Psoriatic Arthritis (PsA) was available for analysis. An anchor-based method using linear regression analyses was used to determine the MICs and MCVs of the PASDAS. With this anchor-based method we compared changes in PASDAS score with an external reference (anchor). The anchor question inquired whether the patient's wellbeing had changed since their previous visit. It consisted of a 7-point Likert scale (range: very much improved to very much deteriorated). Interperiod correlation matrix analysis was performed to determine the SEM.

RESULTS

The overall MIC and MCV of the PASDAS were 0.67 (95% CI; 0.55-0.79) and 1.34 (95% CI; 1.21-1.46), respectively. Results for improvement and deterioration were 0.65 (95% CI; 0.46-0.83) and 0.71 (95% CI; 0.49-0.93) for the MIC, respectively, and 1.29 (95% CI; 1.11-1.48) and 1.42 (95% CI; 1.19-1.64) for the MCV, respectively. The SEM was determined at 0.81.

CONCLUSIONS

The MIC of the PASDAS provides an extra tool for physicians in the treatment of PsA patients to put context to the patient's perspective of disease activity, while the MCV might aid the use of the PASDAS in PsA clinical trials.

Discovery of Arthritis in Psoriasis Patients for Early Rheumatological Referral (DAPPER): Protocol for a Longitudinal Observational Study

Background

One in three patients with psoriasis will develop psoriatic arthritis (PsA). If left untreated, this can lead to pain, impaired function, and irreversible joint damage. Timely recognition and referral to a rheumatologist are therefore key. However, current methods used to screen patients with psoriasis for those who might benefit from referral to a rheumatologist are not performing well enough.

Objective

The Discovery of Arthritis in Psoriasis Patients for Early Rheumatological Referral (DAPPER) study is designed to determine the prevalence of PsA in a psoriasis population and to find parameters that can be used to develop a new or enhance an existing instrument for a rheumatological referral.

Methods

DAPPER is a longitudinal observational study with a 1-year follow-up. Patients with psoriasis (N=300) who are treated at an outpatient dermatological clinic will be screened extensively for signs and symptoms of PsA by a trained rheumatologist. If there is clinical suspicion of PsA and the patient is not yet treated by a rheumatologist, referral to the Department of Rheumatology will follow for confirmation of the diagnosis and further care. After 1 year, data on changes in quality of life and PsA and psoriasis disease activity will be collected from the referred patients. The screening visit will be used to gather demographical and medical data, which can later be used to develop the aforementioned screening instrument.

Results

Inclusion started in June 2019 and finished in June 2021. Follow-up with newly discovered patients with PsA is ongoing.

Conclusions

The DAPPER study is specifically designed to improve the detection of existing PsA in a dermatologic outpatient setting. Although internal validity will be tested, external validity will have to be checked using a second validation cohort. To predict the development of PsA in the future, longitudinal/prospective data collection is required and will be performed in a follow-up study (DAPPER-i).

Trial Registration

Dutch Trial Register NTR7604; https://www.trialregister.nl/trial/7397

International Registered Report Identifier (IRRID)

DERR1-10.2196/31647

Blood-Based Immune Profiling Combined with Machine Learning Discriminates Psoriatic Arthritis from Psoriasis Patients

Psoriasis (Pso) is a chronic inflammatory skin disease, and up to 30% of Pso patients develop psoriatic arthritis (PsA), which can lead to irreversible joint damage. Early detection of PsA in Pso patients is crucial for timely treatment but difficult for dermatologists to implement. We, therefore, aimed to find disease-specific immune profiles, discriminating Pso from PsA patients, possibly facilitating the correct identification of Pso patients in need of referral to a rheumatology clinic. The phenotypes of peripheral blood immune cells of consecutive Pso and PsA patients were analyzed, and disease-specific immune profiles were identified via a machine learning approach. This approach resulted in a random forest classification model capable of distinguishing PsA from Pso (mean AUC = 0.95). Key PsA-classifying cell subsets selected included increased proportions of differentiated CD4+CD196+CD183-CD194+ and CD4+CD196-CD183-CD194+ T-cells and reduced proportions of CD196+ and CD197+ monocytes, memory CD4+ and CD8+ T-cell subsets and CD4+ regulatory T-cells. Within PsA, joint scores showed an association with memory CD8+CD45RA-CD197- effector T-cells and CD197+ monocytes. To conclude, through the integration of in-depth flow cytometry and machine learning, we identified an immune cell profile discriminating PsA from Pso. This immune profile may aid in timely diagnosing PsA in Pso.

Measuring disease activity in psoriatic arthritis: PASDAS implementation in a tightly monitored cohort reveals residual disease burden

OBJECTIVES

We aimed to investigate the disease activity and overall disease burden of (subgroups of) patients with PsA using the Psoriatic Arthritis Disease Activity Score (PASDAS) in an already tightly monitored cohort.

METHODS

This is a cross-sectional study evaluating data from the first visit of 855 PsA patients after implementation of the PASDAS in our tightly monitored cohort [e.g. DAS 28 (DAS28) was provided as an anchor]. Differences in clinical outcomes between subgroups of patients using established cut-offs for disease activity status [i.e. very low (VLDA), low (LDA), moderate (MDA), and high disease activity (HDA)] were examined.

RESULTS

Based on the PASDAS, 53.1% of patients were in VLDA/LDA. 29.5% of patients had ≥1 swollen joint, 20.6% had ≥1 enthesitis index point and 3.0% had active dactylitis. Based on DAS28, 77.5% of the patients were in VLDA/LDA. Patients reaching both DAS28 VLDA/LDA status and PASDAS VLDA/LDA status [N = 445 (52.0%)] were compared with patients reaching only DAS28 VLDA/LDA status [N = 218 (25.5%)]. For these latter patients, significantly worse scores on separate parameters were found in measures used for PASDAS/DAS28 calculation (e.g. swollen and tender joint count and patient's visual analogue scale global disease activity) as well as other disease measures (e.g. function and inflammatory back pain). This result remained, even when the stricter VLDA cut-off was used for the DAS28.

CONCLUSION

PASDAS implementation uncovered relevant residual disease activity in a quarter of patients previously assessed as being in DAS28 VLDA/LDA, underscoring the potential value of PASDAS measurements in PsA clinical care.

Clinical, laboratory, and genetic markers for the development or presence of psoriatic arthritis in psoriasis patients: a systematic review

Twenty to thirty percent of psoriasis (Pso) patients will develop psoriatic arthritis (PsA). Detection of Pso patients that are (at risk for) developing PsA is essential to prevent structural damage. We conducted a systematic search of five bibliographic databases, up to May 2020. We searched for studies assessing markers (clinical, laboratory, genetic) associated with the development or presence of PsA in Pso patients. Study selection and quality assessment of the included studies was performed, followed by a qualitative best evidence synthesis to determine the level of evidence for a marker and its association with concomitant/developing PsA in Pso. Overall, 259 possible markers were identified in 119 studies that met the inclusion criteria. Laboratory markers related to inflammation and bone metabolism reached a strong level of evidence for the association (not prediction) of PsA in Pso. Only CXCL10 showed strong evidence for a positive predictive value for PsA in Pso. The importance of timely detecting PsA in a Pso population, and finding more (bio)markers contributing to early detection, remains high.

Being overweight is associated with not reaching low disease activity in women but not men with Psoriatic Arthritis

OBJECTIVE

To assess sex differences in disease activity parameters and health-related quality of life in Psoriatic arthritis (PsA), and to assess whether determinants associated with not reaching treatment target differed between men and women.

METHODS

Routine practice data of 855 PsA patients, who were all tightly monitored and treated, was used. Sex differences including, but not limited to, Psoriatic Arthritis Disease Activity Score (PASDAS), skin/nail disease, SF12-PCS/MCS, and inflammatory back pain (IBP) were assessed. Multivariate analyses were used to examine determinants associated with not reaching treatment target (PASDAS≤3.2) in men and women.

RESULTS

Women had worse scores for - among others- swollen and tender joints, CRP, enthesitis, and function (all P < 0.001). Higher PASDAS scores were found for women (3.5±1.5) than men (2.7±1.5, p < 0.001). Likewise, women were more often not at PASDAS treatment target (OR = 2.03, P < 0.001). No difference in current medication use was found. Nail disease, IBP, number of DMARDs used (past and current), and Body Mass Index (BMI) were associated with not reaching treatment target in the overall sample. For women, but not men, BMI was associated with not reaching PASDAS low disease activity (LDA) (OR between 2.41-3.43, P < 0.001).

CONCLUSIONS

Women with PsA in a tightly monitored and treated setting have more severe disease than men. This is demonstrated by worse scores for women in both subjective and objective disease activity measures, in addition to women less often reaching the treatment target. Notably, being overweight is associated with higher disease activity in women, but not men.

Increased intra-articular granzyme M may trigger local IFN-λ1/IL-29 response in rheumatoid arthritis

OBJECTIVES

Granzymes are serine proteases involved in eliminating tumour cells and virally infected cells. In addition, extracellular granzyme levels are elevated in inflammatory conditions, including several types of infection and autoimmune diseases, such as rheumatoid arthritis (RA). While GrA and GrB have been associated with RA, a role for the other three granzymes (GrH, GrK, and GrM) in this disease remains unclear. Here, we aimed to investigate the presence and role of GrM and GrK in serum and synovial fluid of patients with RA, psoriatic arthritis, and osteoarthritis.

METHODS

Granzyme levels were determined in serum, synovial fluid, peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) of RA patients and relevant control groups. In addition, the link between GrM and inflammatory cytokines in synovial fluid was investigated.

RESULTS

Serum GrM and GrK levels were not affected in RA. GrM, but not GrK, levels were elevated in synovial fluid of RA patients. GrM was mainly expressed by cytotoxic lymphocytes in SFMCs with a similar expression pattern as compared with PBMCs. Intra-articular GrM expression correlated with IL-25, IL-29, XCL1, and TNFα levels. Intriguingly, purified GrM triggered the release of IL-29 (IFN-λ1) from human fibroblasts in vitro.

CONCLUSIONS

These data indicate that GrM levels are increased in RA synovial fluid and that GrM can stimulate proinflammatory IL-29 release from fibroblasts, suggesting a role of GrM in the pathogenesis of RA.

Comparing methotrexate monotherapy with methotrexate plus leflunomide combination therapy in psoriatic arthritis: protocol of a randomized, placebo-controlled, double-blind clinical trial (COMPLETE-PsA)

Background

Both methotrexate (MTX) and leflunomide (LEF) are registered and regularly prescribed as first-line treatments for the use in patients with psoriatic arthritis (PsA) and they are occasionally used in combination. However, evidence about their individual, and especially combined efficacy, in PsA is lacking. The aim of this study is to compare the effectiveness and safety of MTX and LEF combination therapy to MTX monotherapy in patients with PsA.

Methods

COMPLETE-PsA is a randomized, placebo-controlled, double-blind clinical trial. Disease-modifying antirheumatic drug (DMARD)-untreated patients (n = 78) with clinical diagnosis of active (i.e. ≥2 swollen joints) PsA will be randomized 1:1 (stratified for high disease activity, Psoriatic Arthritis Disease Activity Score [PASDAS] ≥ 5.4) to the combination or monotherapy. The intervention group receives MTX 25 mg (oral or subcutaneous) once weekly plus LEF 20 mg daily, and the control group receives the same but with placebo instead of LEF daily. Primary endpoint is between-group difference in PASDAS at 16 weeks, adjusted for baseline PASDAS. Key secondary parameters include between-group comparisons in change in Disease Activity in Psoriatic Arthritis (DAPSA) score, skin score, enthesitis score, dactylitis score, and swollen/tender joint count, as well as the proportion of patients fulfilling minimal disease activity (MDA), American College of Rheumatology (ACR) 20/50/70 response criteria at week 16. Furthermore, safety, function and quality of life (Health Assessment Questionnaire [HAQ], Psoriatic Arthritic Impact of Disease [PSAID], Short Form 12 [SF-12]) will be assessed.

Discussion

This is, to our knowledge, the first randomized, placebo-controlled, double-blind clinical trial assessing the effectiveness of MTX and LEF combination therapy in patients with PsA. The study will provide important information for treatment strategies and treatment recommendations.

Trial registration

Dutch Trial Register NTR7632 (3 December 2018). CMO NL66544.091.18 (19 November 2018).

Dose reduction and withdrawal strategy for TNF-inhibitors in psoriatic arthritis and axial spondyloarthritis: design of a pragmatic open-label, randomised, non-inferiority trial

BACKGROUND

Tumour necrosis factor inhibitors (TNFi) are effective in the treatment of patients with spondyloarthritis (SpA), including psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). However, these drugs come with some disadvantages such as adverse events, practical burden for patients and high costs. Dose optimisation of TNFi after patients have reached low disease activity (LDA) has been shown feasible and safe in rheumatoid arthritis (RA). However, data on TNFi dose optimisation in PsA and axSpA are scarce, especially pragmatic, randomised strategy studies.

METHODS

We developed an investigator-driven, pragmatic, open-label, randomised, controlled, non-inferiority trial (DRESS-PS) to compare the effects of a disease activity-guided treat-to-target strategy with or without a tapering attempt in patients with SpA (PsA and axSpA combined), ≥ 16 years of age, who are being treated with TNFi, and have had at least 6 months of low disease activity. The primary outcome is the percentage of patients in LDA after 12 months of follow up. Patients are assessed at baseline, 3, 6, 9, and 12 months of follow up. Bayesian power analyses with a weakened prior based on a similar study performed in RA resulted in a sample size of 95 patients in total.

DISCUSSION

More knowledge on disease activity-guided treatment algorithms would contribute to better treatment choices and cost savings and potentially decrease the risk of side effects. In this article we elucidate some of our design choices on TNFi dose optimisation and its clinical and methodological consequences.

TRIAL REGISTRATION

Dutch Trial Register, NL6771. Registered on 27 November 2018 (CMO NL66181.091.18, 23 October 2018).

Preferences of patients with rheumatoid arthritis regarding disease-modifying antirheumatic drugs: a discrete choice experiment

BACKGROUND

Although patients have different treatment preferences, these individual preferences could often be grouped in subgroups with shared preferences. Knowledge of these subgroups as well as factors associated with subgroup membership supports health care professionals in the understanding of what matters to patients in clinical decision-making.

OBJECTIVES

To identify subgroups of patients with rheumatoid arthritis (RA) based on their shared preferences toward disease-modifying antirheumatic drugs (DMARDs), and to identify factors associated with subgroup membership.

METHODS

A discrete choice experiment to determine DMARD preferences of adult patients with RA was designed based on a literature review, expert recommendations, and focus groups. In this multicenter study, patients were asked to state their preferred choice between two different hypothetical treatment options, described by seven DMARD characteristics with three levels within each characteristic. Latent class analyses and multinomial logistic regressions were used to identify subgroups and the characteristics (patient characteristics, disease-related variables, and beliefs about medicines) associated with subgroup membership.

RESULTS

Among 325 participating patients with RA, three subgroups were identified: an administration-driven subgroup (45.6%), a benefit-driven subgroup (29.7%), and a balanced subgroup (24.7%). Patients who were currently using biologic DMARDs were significantly more likely to belong to the balanced subgroup than the administration-driven subgroup (relative risk ratio (RRR): 0.50, 95% CI: 0.28-0.89). Highly educated patients were significantly more likely to belong to the benefit-driven subgroup than the balanced subgroup (RRR: 11.4, 95% CI: 0.97-133.6). Patients' medication-related concerns did not contribute significantly to subgroup membership, whereas a near-significant association was found between patients' beliefs about medication necessity and their membership of the benefit-driven subgroup (RRR: 1.12, 95% CI: 1.00-1.23).

CONCLUSION

Three subgroups with shared preferences were identified. Only biologic DMARD use and educational level were associated with subgroup membership. Integrating patient's medication preferences in pharmacotherapy decisions may improve the quality of decisions and possibly medication adherence.

Rheumatoid Arthritis Patients With Circulating Extracellular Vesicles Positive for IgM Rheumatoid Factor Have Higher Disease Activity

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that mainly affects synovial joints. Validated laboratory parameters for RA diagnosis are higher blood levels of rheumatoid factor IgM (IgM-RF), anti-citrullinated protein autoantibodies (ACPA), C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR). Clinical parameters used are the number of tender (TJC) and swollen joints (SJC) and the global patient visual analog score (VAS). To determine disease remission in patients a disease activity score (DAS28) can be calculated based on SJC, TJC, VAS, and ESR (or alternatively CRP). However, subtle and better predictive changes to follow treatment responses in individual patients cannot be measured by the above mentioned parameters nor by measuring cytokine levels in blood. As extracellular vesicles (EVs) play a role in intercellular communication and carry a multitude of signals we set out to determine their value as a biomarker for disease activity. EVs were isolated from platelet-free plasma of 41 RA patients and 24 healthy controls (HC) by size exclusion chromatography (SEC). We quantified the particle and protein concentration, using NanoSight particle tracking analysis and micro-BCA, respectively, and observed no differences between RA patients and HC. In plasma of 28 out of 41 RA patients IgM-RF was detectable by ELISA, and in 13 out of these 28 seropositive RA patients (RF⁺RA) IgM-RF was also detected on their isolated pEVs (IgM-RF⁺). In seronegative RA patients (RF^-RA) we did not find any RF present on pEVs. When comparing disease parameters we found no differences between RF⁺RA and RF^-RA patients, except for increased ESR levels in RF⁺RA patients. However, RF⁺RA patients with IgM-RF⁺ pEVs showed significantly higher levels of CRP and ESR and also VAS and DAS28 were significantly increased compared to RA⁺ patients without IgM-RF⁺ pEVs. This study shows for the first time the presence of IgM-RF on pEVs in a proportion of RF⁺RA patients with a higher disease activity.

Impaired Porphyromonas gingivalis-Induced Tumor Necrosis Factor Production by Dendritic Cells Typifies Patients With Rheumatoid Arthritis

OBJECTIVE

The prevalence of periodontitis is increased in patients with rheumatoid arthritis (RA), and the severity of periodontitis can affect the level of arthritis. Porphyromonas gingivalis is one of the main bacteria involved in periodontitis. Our aim was to determine if there are differences in the innate immune response against P gingivalis between healthy controls and RA patients.

METHODS

Monocyte-derived dendritic cells (DCs) from healthy controls, RA patients, and patients with psoriatic arthritis (PsA) were stimulated with P gingivalis, a range of other bacteria, and Toll-like receptor agonists. Cytokine production was determined, and blocking studies were performed to determine which receptors were involved in differential recognition of P gingivalis. Effects on T cell cytokines were also determined in cultures of peripheral blood mononuclear cells (PBMCs).

RESULTS

Upon stimulation with P gingivalis, RA patient DCs produced less tumor necrosis factor as compared to healthy control DCs, which was not observed in PsA patients or upon stimulation with other bacteria. In addition, P gingivalis-mediated activation of RA patient PBMCs showed a clear reduction of interferon-γ production. Among the various possible underlying mechanisms investigated, only blockade of CR3 abolished the difference between RA patients and healthy controls, suggesting the involvement of CR3 in this process.

CONCLUSION

Immune cells from RA patients display a reduced response to P gingivalis, which has functional consequences for the immune response. This may result in prolonged survival of P gingivalis, possibly driving autoantibody formation and a self-perpetuating loop of chronic inflammation. The possible role of CR3 in this process warrants further investigation.

Fc gamma receptor IIb on GM-CSF macrophages controls immune complex mediated inhibition of inflammatory signals

BACKGROUND

In rheumatoid arthritis (RA) macrophages play a major role in amplifying synovial inflammation. Important activating signals are those induced by Toll-like receptor (TLR) ligands and by activated T cells. The balance between activating and inhibitory Fc gamma receptors (FcγRs) on macrophages might be crucial in modulating these inflammatory responses. The purpose of this study was to determine FcγR expression on pro- and anti-inflammatory macrophages (gmMφ and mMφ, respectively) and identify functional consequences on immune complex uptake and macrophage activation.

METHODS

Human monocytes were isolated and differentiated into gmMφ and mMφ. A full FcγR characterization of both macrophage subtypes was performed and uptake of fluorescent immune complexes (ICs) was determined. FcγRIIb isoforms were determined by qPCR. Macrophages were stimulated via different TLRs or cytokine activated T cells in the presence or absence of ICs and cytokine production was determined. Blocking studies were performed to look into the pathways involved.

RESULTS

mMφ expressed high levels of the activating FcγRIIa and FcγRIII and low levels of the inhibitory FcγRIIb, while the FcγR balance on gmMφ was shifted towards the inhibitory FcγRIIb. This was accompanied by a clear increase in FcγRIIb1 mRNA expression in gmMφ. This resulted in higher IC uptake by mMφ compared to gmMφ. Furthermore, FcγR-mediated stimulation of gmMφ inhibited TLR2, 3, 4 and 7/8 mediated cytokine production via FcγRIIb and PI3K signaling. In addition, gmMφ but not mMφ produced TNFα upon co-culture with cytokine activated T cells, which was reduced by IC binding to FcγRIIb. The latter was dependent on PI3K signaling and COX2.

CONCLUSIONS

FcγR expression patterns on gmMφ and mMφ are significantly different, which translates in clear functional differences further substantiating FcγRIIb as an interesting target for inflammation control in RA and other autoimmune/inflammatory diseases.

Soluble immune complexes shift the TLR-induced cytokine production of distinct polarized human macrophage subsets towards IL-10

BACKGROUND

Costimulation of murine macrophages with immune complexes (ICs) and TLR ligands leads to alternative activation. Studies on human myeloid cells, however, indicate that ICs induce an increased pro-inflammatory cytokine production. This study aimed to clarify the effect of ICs on the pro- versus anti-inflammatory profile of human polarized macrophages.

MATERIALS AND METHODS

Monocytes isolated from peripheral blood of healthy donors were polarized for four days with IFN-γ, IL-4, IL-10, GM-CSF, M-CSF, or LPS, in the presence or absence of heat aggregated gamma-globulins (HAGGs). Phenotypic polarization markers were measured by flow cytometry. Polarized macrophages were stimulated with HAGGs or immobilized IgG alone or in combination with TLR ligands. TNF, IL-6, IL-10, IL-12, and IL-23 were measured by Luminex and/or RT-qPCR.

RESULTS

HAGGs did not modulate the phenotypic polarization and the cytokine production of macrophages. However, HAGGs significantly altered the TLR-induced cytokine production of all polarized macrophage subsets, with the exception of MΦ(IL-4). In particular, HAGGs consistently enhanced the TLR-induced IL-10 production in both classically and alternatively polarized macrophages (M1 and M2). The effect of HAGGs on TNF and IL-6 production was less pronounced and depended on the polarization status, while IL-23p19 and IL-12p35 expression was not affected. In contrast with HAGGs, immobilized IgG induced a strong upregulation of not only IL-10, but also TNF and IL-6.

CONCLUSION

HAGGs alone do not alter the phenotype and cytokine production of in vitro polarized human macrophages. In combination with TLR-ligands, however, HAGGs but not immobilized IgG shift the cytokine production of distinct macrophage subsets toward IL-10.

Abatacept modulates proinflammatory macrophage responses upon cytokine-activated T cell and Toll-like receptor ligand stimulation

OBJECTIVES

We investigated whether Abatacept might reduce proinflammatory cytokine production by macrophages upon contact with cytokine activated T cells and/or stimulation with TLR ligands.

METHODS

Macrophages and cytokine stimulated T cells (Tck) were added together in the presence of Abatacept or a control Ig, with or without TLR ligands. The production of cytokines was determined by luminex.

RESULTS

Abatacept reduced Tck-induced production of TNFa by macrophages. Tck and TLR ligands synergistically induced the production of proinflammatory cytokines by macrophages, especially IL-12p70. The production of IL-12p70 coincided with the production of IFNg, which were both reduced in the presence of Abatacept.

CONCLUSIONS

Tck induce the production of TNFa by macrophages and facilitate the highly increased production of proinflammatory cytokines in the presence of TLR ligands. Abatacept was shown to potently suppress these pathways suggesting that its role may extend beyond antigen specific T cell mediated effector function.

Toll-like receptors in rheumatic diseases: are we paying a high price for our defense against bugs?

In the last decade Toll-like receptor (TLR) research has led to new insights in the pathogenesis of many rheumatic diseases. In autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis TLR signaling is likely to be involved in tolerance breakthrough and chronic inflammation via combined Fc gamma receptors and TLR recognition of immune complexes. Furthermore, inflammatory diseases like psoriatic arthritis and gout also show more and more evidence for TLR involvement. In this review we will discuss the involvement of TLR signaling in several rheumatic diseases and stress their similarities and differences based on recent findings.

TLR2 promotes Th2/Th17 responses via TLR4 and TLR7/8 by abrogating the type I IFN amplification loop

TLR2 plays an important role in the removal of Gram-positive bacteria; contrastingly, it also appears to have important protective effects against unrestrained inflammation and subsequent organ injury during infection and autoimmunity. We hypothesized that TLR2 tunes the phenotype of dendritic cells (DCs) activated through other TLRs, thereby fulfilling a crucial role in the modulation of the immune response. TLR2 potently inhibited TLR4- and TLR7/8-induced cytokine production by human DCs. The inhibitory effect of TLR2 on the release of TNF-alpha but not of IL-12p70 was mediated by PI3K. TLR2 inhibits the production of IL-12p70 by dampening the type 1 IFN amplification loop. When DCs were triggered with the potent synergistic combination of LPS (TLR4) and R848 (TLR7/8) in conjunction with a TLR2 ligand, a clear shift to more Th2- and Th17-prone responses in the naive and memory T cell subpopulations was observed. This shift in T cell responses was inherent to the inability of TLR2-stimulated DCs to produce IL-12p70 and was dependent on the production of IL-1 and IL-6.

The inhibitory Fc gamma IIb receptor dampens TLR4-mediated immune responses and is selectively up-regulated on dendritic cells from rheumatoid arthritis patients with quiescent disease

Rheumatoid arthritis (RA) is a common autoimmune disease leading to profound disability and premature death. Although a role for FcgammaRs and TLRs is accepted, their precise involvement remains to be elucidated. FcgammaRIIb is an inhibitory FcR important in the maintenance of tolerance. We hypothesized that the inhibitory FcgammaRIIb inhibits TLR responses on monocyte-derived dendritic cells (DC) and serves as a counterregulatory mechanism to dampen inflammation, and we surmised that this mechanism might be defective in RA. The expression of the inhibitory FcgammaRIIb was found to be significantly higher on DCs from RA patients having low RA disease activity in the absence of treatment with antirheumatic drugs. The expression of activating FcgammaRs was similarly distributed among all RA patients and healthy controls. Intriguingly, only DCs with a high expression of FcgammaRIIb were able to inhibit TLR4-mediated secretion of proinflammatory cytokines when stimulated with immune complexes. In addition, when these DCs were coincubated with the combination of a TLR4 agonist and immune complexes, a markedly inhibited T cell proliferation was apparent, regulatory T cell development was promoted, and T cells were primed to produce high levels of IL-13 compared with stimulation of the DCs with the TLR4 agonist alone. Blocking FcgammaRIIb with specific Abs fully abrogated these effects demonstrating the full dependence on the inhibitory FcgammaRIIb in the induction of these phenomena. This TLR4-FcgammaRIIb interaction was shown to dependent on the PI3K and Akt pathway.

Dendritic cells and their potential implication in pathology and treatment of rheumatoid arthritis

Dendritic cells (DC) are the professional antigen presenting cells that protect us against invading organisms. On the other hand, they uphold tolerance thereby avoiding the initiation of autoimmunity. In performing these contrasting but essential tasks DC are unique and divide these processes in time and space. It is often thought that a loss of separation of these tasks underlies the breakthrough of tolerance leading to autoimmune conditions such as rheumatoid arthritis. In this review, we will focus on the evidence which points towards the implication of DC in the inflammatory process observed in RA and in experimental models of arthritis. Finally, we will conclude on future programs exploiting the capacity of DC to cure conditions such as RA.

Type I interferons might form the link between Toll-like receptor (TLR) 3/7 and TLR4-mediated synovial inflammation in rheumatoid arthritis (RA)

BACKGROUND

Rheumatoid arthritis (RA) has been associated with an increased risk of infections, but the underlying pathways have not yet been identified. Toll-like receptors (TLR) probably play a role in synovial inflammation and may also contribute to the understanding of the role of infections in RA.

OBJECTIVES

To investigate if the synovial expression of TLR3 and TLR7 in RA correlates with that of inflammatory cytokines, and to assess whether this has functional consequences for local cytokine production and to study potential links between the TLR3/7 axis and TLR4 in RA synovium.

METHODS

Immunohistochemistry was used to study the expression of TLR3, TLR7, interferon alpha (IFNalpha), tumour necrosis factor alpha (TNFalpha) and interleukins IL1beta, IL12, IL17 and IL18 in RA synovium obtained by arthroscopy from 34 patients with RA. Monocytes, monocyte-derived dendritic cells (MoDCs) and RA synovial fibroblasts were stimulated via TLR3 (poly-IC) and TLR7 (loxorubin), after which IL1beta, IL6 and TNFalpha were measured by Luminex bead array technology. Following preincubation with IFNalpha, IL1beta and IL18, TLR3 and TLR7 mRNA expression was assessed using real-time PCR. Cytokine production after preincubation with IFNalpha and subsequent TLR stimulation was measured.

RESULTS

Synovial TLR3/7 expression was co-expressed with IFNalpha, IL1beta and IL18, but not with TNFalpha, IL12 and IL17. Stimulation of TLR3/TLR7 on monocytes, MoDCs or synovial fibroblasts led to secretion of type I IFN but no biologically active IL1beta or IL18 could be detected. Type I IFNalpha increased TLR3/7 mRNA expression whereas IL1beta and IL18 did not. In spite of the fact that the mRNA level of TLR4 remained unchanged, IFNalpha enhanced the response to TLR4 agonists, a phenomenon that was clearly more marked in patients with RA.

CONCLUSION

Type I interferons are highly co-expressed with TLR3/TLR7 in RA synovium. They enhance TLR3/TLR7-mediated cytokine production and also TLR4-mediated responses.

The functional variant (Asp299gly) of toll-like receptor 4 (TLR4) influences TLR4-mediated cytokine production in rheumatoid arthritis

OBJECTIVE

To investigate functional consequences of the Toll-like receptor 4 (TLR4) variant (Asp299Gly) in rheumatoid arthritis (RA).

METHODS

Peripheral blood mononuclear cells from 28 patients with RA carrying or not carrying the TLR4 variant were incubated with lipopolysaccharide (LPS) and heat shock protein B8 (HSPB8). Concentrations of interleukin 6 (IL-6), tumor necrosis factor-alpha(TNF-alpha), and IL-10 were determined along with TLR4 and CD14 expression.

RESULTS

TLR4 expression was similar in patients carrying or not carrying the variant. In contrast, both LPS and HSPB8 resulted in significantly lower secretion of IL-6, TNF-alpha, and IL-10 in those who carried the variant, whereas the frequency of CD14+ cells was higher in these individuals.

CONCLUSION

TLR4 variant clearly reduces its potency to mediate signaling. Correction for CD14+ cells is necessary in comparable experiments.

Fc gamma receptor mediated modulation of dendritic cells as a potential strategy in the battle against rheumatoid arthritis

Autoimmune diseases such as rheumatoid arthritis (RA) result from a deregulation of immune responses culminating in immune-mediated tissue injury. In RA, this tissue injury is mainly reflected by synovitis and subsequent joint damage, although involvement of visceral organs (heart, lungs and kidneys) often leads to severe comorbidity. Accumulating evidence points towards dendritic cells (DC) as the principal regulators of the balance between immunity and tolerance. Recently, a large body of evidence has demonstrated that the balance between activating and inhibitory Fc gamma receptor (Fc gammaR) subtypes is intricately involved in the regulation of DC behaviour. In this overview we summarise recent findings from our group and others that suggest an important role for Fc gammaR in arthritis. Furthermore, we postulate novel mechanisms of how triggering of Fc gammaR might be used to manipulate DC function and combat autoimmunity. When DC are envisaged as useful targets in the light of DC immunotherapy in RA, detailed knowledge on the regulatory pathways of Fc gammaR in RA is of paramount importance.

The functional variant of the inhibitory Fcγ receptor IIb (CD32B) is associated with the rate of radiologic joint damage and dendritic cell function in rheumatoid arthritis

OBJECTIVE

Fcgamma receptors (FcgammaRs) recognize immune complexes (ICs) and coordinate the immune response by modulating the functions of dendritic cells (DCs). The purpose of this study was to unravel the role of the inhibitory FcgammaRIIb in rheumatoid arthritis (RA) by studying the effect of the FCGR2B 695T>C polymorphism on susceptibility to RA, severity of the disease, and DC function.

METHODS

Genotyping was performed in RA patients (n = 246) and healthy blood donors (n = 269). The patients' demographic data, disease severity, and disease progression were assessed over a followup of 6 years. DCs were cultured for flow cytometry to determine the expression of FcgammaRs. For detection of FcgammaRIIb (CD32B), a unique anti-FcgammaRIIb antibody (2B6-fluorescein isothiocyanate [FITC]) was used. The capacity for antigen uptake by DCs was studied by assessing the uptake of FITC-labeled ICs. Levels of cytokine production by DCs were measured during lipopolysaccharide-mediated cell activation in the presence and absence of ICs.

RESULTS

Although no role of the FCGR2B variant in RA susceptibility was demonstrated, this variant was associated with a nearly doubled rate of radiologic joint damage during the first 6 years of RA. Multiple regression analysis showed that FCGR2B was by far the strongest predictor of joint damage identified to date. DCs from patients carrying this variant failed to display the inhibitory phenotype normally observed upon IC-mediated triggering of inflammation and displayed diminished FcgammaRII-mediated antigen uptake compared with wild-type DCs. However, the levels of FcgammaRs were not affected, suggesting that the FCGR2B variant alters the function rather than regulation of proteins.

CONCLUSION

This study is the first to show that a single genetic variant, the FCGR2B 695T>C polymorphism, is a critical determinant of disease severity in RA and radically changes DC behavior. Our results underscore the key role of DCs in the progression of RA and reveal FcgammaRIIb as an important potential therapeutic target in RA and other autoimmune conditions.

Dendritic cells from patients with rheumatoid arthritis lack the interleukin 13 mediated increase of Fc gamma RII expression, which has clear functional consequences

BACKGROUND

Dendritic cell (DC) function is largely tailored by Fc gamma receptors (Fc gamma R) and is critical for every immune response.

OBJECTIVE

To compare interleukin (IL) 13 mediated regulation of Fc gamma RII and its related DC function between healthy controls and patients with rheumatoid arthritis (RA).

METHODS

DC were derived from peripheral blood mononuclear cells according to standardised protocols. F cgammaRI, II, and III expression and DC phenotype were assessed by FACS analysis. The level of cytokine production and chemokine expression was measured by Luminex and real time quantitative polymerase chain reaction techniques. Antigen uptake capacity was studied by DC fluorescent heat aggregated immunoglobulins and FACS analysis.

RESULTS

Replacement of IL4 by IL13 clearly increased the expression of Fc gamma RII on DC from healthy controls (CDC), but had no effect on DC from patients with RA (RADC). The lower production of inflammatory mediators by IL13 CDC upon Fc gamma R mediated triggering suggests that IL13 induces up regulation of specifically Fc gamma RII. RADC co-cultured with IL4 already displayed an inhibitory DC phenotype, but this inhibitory phenotype was not augmented by the addition of IL13. The defective Fc gamma RII regulation was further substantiated by the finding that IL13 CDC increased antigen uptake capacity, whereas IL13 RADC did not.

CONCLUSION

IL13 regulates the expression of inhibitory Fc gamma RII in normal subjects but not in RA, potentially resulting in a chronic proinflammatory immune reaction in RA. Unravelling the underlying mechanisms of Fc gamma RII regulation might lead to new therapeutic targets in RA.