Increased synovial galectin-3 induce inflammatory fibroblast activation and osteoclastogenesis in patients with rheumatoid arthritis.

OBJECTIVE: Galectin-3 (Gal-3) has been suggested as a proinflammatory mediator in rheumatoid arthritis (RA). We aimed to study clinical and pathogenic aspects of Gal-3 in RA. METHOD: Plasma samples from healthy controls (n = 48) and patients with newly diagnosed, early RA were assayed for soluble Gal-3. In patients with chronic RA (n = 18), Gal-3 was measured in both plasma and synovial fluid. Synovial fluid mononuclear cells were used to purify fibroblast-like synoviocytes (FLSs) and osteoclasts. Monocultures of FLSs and autologous co-cultures of FLSs and peripheral blood mononuclear cells were established and co-incubated with a Gal-3 inhibitor. RESULTS: Patients with early and chronic RA had persistently increased plasma levels of Gal-3 compared with controls. However, changes in plasma Gal-3 at the level of individuals were associated with long-term disease activity. In seropositive early RA patients, all patients with decreasing plasma Gal-3 from 0 to 3 months had low disease activity after 2 years (p < 0.05). Gal-3 levels in synovial fluid were markedly elevated. In vitro, co-incubation with a Gal-3 inhibitor (GB1107, 10 µM) led to a significant reduction in both interleukin-1ß and tumour necrosis factor-α secretion from FLS monocultures (both p < 0.05) and decreased monocyte-derived osteoclastogenesis compared with controls (both p < 0.05). CONCLUSIONS: Our findings underscore the role of Gal-3 regarding disease activity and tissue destruction in RA. An initial decrease in plasma Gal-3 levels predicted decreased long-term disease activity. Correspondingly, a Gal-3 inhibitor decreased the activity of inflammatory FLSs and osteoclastogenesis in patients with RA.

Baseline serum levels of IgA anti-cyclic citrullinated protein antibodies in early rheumatoid arthritis predict radiographic progression after 11 years of treatment: a secondary analysis of the CIMESTRA study.

OBJECTIVE: Smoking and periodontitis are risk factors for developing rheumatoid arthritis (RA), suggesting a break of tolerance on mucosal surfaces. Immunoglobulin A (IgA) antibodies are part of the mucosal immune system. The dominant autoantibodies in RA are anti-cyclic citrullinated protein antibodies (ACPAs), and IgG and IgA subclasses exist simultaneously. This study aimed to investigate the association of ACPA IgA subtypes with disease activity and long-term radiographic outcomes in RA, compared with ACPA IgG. METHOD: Total ACPA IgG, IgA, IgA1, and IgA2 were quantified in serum from patients with early RA (n = 97). Patient characteristics, IgM rheumatoid factor (IgM-RF) status, clinical and biochemical disease activity scores, and radiographic status evaluated by total Sharp score (TSS), were assessed at baseline and after 2 and 11 years of treatment. RESULTS: All patients with ACPA IgA also had ACPA IgG. ACPA IgA positivity was associated with IgM-RF and male gender. Both ACPA IgA and IgG levels at baseline were weakly associated with disease activity markers. Baseline ACPA IgA and IgG did not show a linear correlation with radiographic status after 10 years, but could predict radiographic progression (ΔTSS ≥ 5 from 0 to 11 years), with positive likelihood ratios of 3.7 and 4.0, respectively. CONCLUSION: ACPA IgA and IgG were weakly associated with disease activity in early RA. RA patients with a ΔTSS ≥ 5 after 11 years of treatment had higher ACPA IgG and ACPA IgA levels at baseline; however, none of the ACPA subtypes was superior in predicting long-term radiographic progression.

Increased interleukin (IL)-20 and IL-24 target osteoblasts and synovial monocytes in spondyloarthritis.

The pathogenesis of spondyloarthritis (SpA) involves activation of the innate immune system, inflammation and new bone formation. The two cytokines interleukin (IL)-20 and IL-24 have been shown to link innate immune activation and tissue homeostasis. We hypothesized that these two cytokines are secreted as part of activation of the innate immune system and affect bone homeostasis in SpA. IL-20 and IL-24 were measured in plasma from axial SpA patients (n = 83). Peripheral SpA patients (n = 16) were included for in-vitro cell culture studies. The plasma IL-20 and IL-24 levels were increased in SpA patients compared with healthy controls (HCs) by 57 and 83%, respectively (both P < 0·0001). The Toll-like receptor 4-induced secretion of the two cytokines was greater in SpA peripheral blood mononuclear cells (PBMCs) compared with HC PBMCs. IL-20 and IL-24 increased the production of monocyte chemoattractant protein-1 by activated SpA synovial fluid monocytes, decreased the production of Dickkopf-1 by SpA fibroblast-like synovial cells and induced mineralization in human osteoblasts. Taken together, our findings indicate disease-aggravating functions of IL-20 and IL-24 in SpA.

TSLP, IL-31, IL-33 and sST2 are new biomarkers in endophenotypic profiling of adult and childhood atopic dermatitis.

BACKGROUND: Recent years have seen growing interest in identifying new biomarkers in atopic dermatitis (AD) that could serve as indicators of disease severity and predictors of treatment response. OBJECTIVES: We compared serum levels of thymic stromal lymphopoietin (TSLP), interleukin(IL)-31, IL-33 and soluble(s)ST2 in AD patients and healthy controls, investigated the possible correlation with disease severity, investigated if other atopic comorbidities could play a role, and assessed their potential as biomarkers in AD. METHODS: Using standard enzyme-linked immunosorbent assay techniques, we measured target serum levels in 71 adults and 61 children with AD, and 31 adult controls. We characterized our cohort by disease severity, radioallergosorbent test status concerning both dietary and inhalant allergens, and anamnestic reports of food allergy, concomitant allergic asthma and/or allergic rhinitis. RESULTS: Serum levels of TSLP, IL-31 and IL-33, but not sST2, were significantly elevated in AD patients compared with controls. In AD patients, both IL-31 and IL-33 serum levels were higher in children than in adults, while the opposite was the case for sST2. We observed no correlation between disease severity and any of the investigated targets. While serum TSLP levels were unaffected by concomitant allergies and atopic comorbidities, serum levels of IL-31, IL-33 and sST2 were affected to a small extent. We found a positive correlation between TSLP, IL-31 and IL-33, and an inverse relationship between IL-33 and sST2. CONCLUSIONS: The studied targets hold little potential as indicators of disease severity. The serum values of our targets show robustness against atopic comorbidities, allergies and changes in disease severity. This robustness strengthens their potential use in biomarker-based stratification and could be instrumental in identifying subgroups and predicting the possible benefit of therapeutic and prevention approaches.

Interleukin-23 in early disease development in rheumatoid arthritis.

OBJECTIVES: To investigate the levels of interleukin (IL)-23 in patients with early rheumatoid arthritis (eRA) and the effect of anti-tumour necrosis factor (anti-TNF)-α treatment on IL-23 levels. METHOD: Treatment-naïve eRA patients from the OPERA cohort were included (n = 151). Patients were randomized to methotrexate (MTX) plus adalimumab (ADA; n = 75) or MTX plus placebo-ADA (PLA; n = 76). Plasma samples were obtained at baseline and at months 3, 6, and 12 together with values for C-reactive protein (CRP), the 28-joint Disease Activity Score based on CRP (DAS28CRP), scores on the Clinical Disease Activity Index (CDAI) and the Simplified Disease Activity Index (SDAI), visual analogue scale (VAS) for pain/fatigue/physician global and total Sharp/van der Heijde score (TSS). IL-23 was measured at each time point. RESULTS: IL-23 levels decreased significantly in the ADA group from 20.6 pg/mL (IQR 13.1-32.7 pg/mL) at baseline to 18 pg/mL (IQR 7.2-25.0 pg/mL) at 12 months (p < 0.01). No significant decrease in IL-23 level was observed in the PLA group. No associations between baseline IL-23 levels and measures of disease activity (DAS28CRP, CRP, CDAI, or SDAI) at 12 or 24 months were present in the treatment groups. Baseline IL-23 correlated inversely with changes in TSS and symptom duration before diagnosis. CONCLUSIONS: Our data show increased baseline levels and a significant decrease in IL-23 levels in eRA patients treated with anti-TNF-α. The inverse correlation with duration of symptoms before diagnosis supports the importance of IL-23 in the preclinical disease development of RA.

Toll-like receptor 2 and 4 induced interleukin-19 dampens immune reactions and associates inversely with spondyloarthritis disease activity.

Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases affecting joints, gut, skin and entheses. The inflammatory process involves activation of Toll-like receptor (TLR)-2 and TLR-4 and production of cytokines and chemokines such as monocyte chemoattractant protein 1 (CCL2/MCP-1). This proinflammatory chemokine recruits monocytes to sites of inflammation and is central in the development of several immune-mediated inflammatory diseases. Interleukin (IL)-19 is a member of the IL-10 family of cytokines. IL-19-deficient mice are more susceptible to innate-mediated colitis and develop more severe inflammation in response to injury. In this work, we studied inducers of IL-19 production and effect of IL-19 on the production of CCL2/MCP-1 and proinflammatory cytokines in peripheral blood mononuclear cells (PBMCs) from healthy controls (HCs) and in PBMCs and synovial fluid mononuclear cells (SFMCs) from SpA patients. Further, we measured IL-19 in plasma from HCs and in plasma and synovial fluid from SpA patients. Constitutive IL-19 expression was present in both PBMCs and SFMCs and the secretion of IL-19 was increased by TLR-2 and TLR-4 ligands. Neutralizing IL-19 in HC PBMCs and SpA SFMCs resulted in increased production of CCL-2/MCP-1. IL-19 concentrations were decreased in synovial fluid compared with plasma and associated inversely with disease activity in SpA. SpA SFMCs produced less IL-19 in response to LPS compared with HC PBMCs. These findings indicate that IL-19 production is diminished in SpA. Taken together, impaired IL-19 control of the innate immune system might be involved in the pathogenesis of SpA.

Increased soluble programmed death-1 (sPD-1) is associated with disease activity and radiographic progression in early rheumatoid arthritis.

OBJECTIVES: Programmed death-1 (PD-1) is an immunoregulatory molecule functioning by down-regulating immune responses. PD-1 is present on follicular helper T cells (TFH) and is important in the formation of plasma cells. PD-1 exists in a bioactive soluble form (sPD-1) and is thought to be implicated in disease activity in chronic rheumatoid arthritis (RA). METHOD: We measured sPD-1 at baseline and 9 months after treatment initiation in plasma from early RA patients (n = 34). We tested for correlations with the Disease Activity Score using 28 joint counts (DAS28), the Health Assessment Questionnaire (HAQ) score, immunoglobulin M rheumatoid factor (IgM-RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, C-reactive protein (CRP), interleukin-21 (IL-21), and total Sharp score (TSS). We also measured sPD-1 in plasma from healthy volunteers (HV) (n = 20) and in plasma and synovial fluid (SF) from patients with chronic RA (> 8 years of disease, n = 30). We further investigated the cellular expression of PD-1 and its ligand PD-L1. RESULTS: sPD-1 concentrations in early [median 0.421 ng/mL, interquartile range (IQR) 0.04-2.560 ng/mL] and chronic (median 0.239 ng/mL, IQR 0.184-0.584 ng/mL) RA were increased compared with HV (median 0.04 ng/mL, IQR 0.04-0.04 ng/mL) (all p < 0.005). In early RA the change in sPD-1 was associated with DAS28 (r = 0.363, p < 0.05) and HAQ score (r = 0.554, p < 0.05) and inversely with TSS at 3-5 years (r = -0.468, p < 0.05). sPD-1 concentration correlated with IgM-RF, anti-CCP antibodies, and IL-21 (all p < 0.05). PD-1 was primarily expressed by synovial memory T cells whereas PD-L1 was mainly expressed by synovial monocytes. CONCLUSIONS: The significantly elevated plasma levels of sPD-1 in early RA, the association with core disease parameters, and the inverse correlation with TSS suggest that sPD-1 is an important mediator in inflammatory and radiographic disease progression.

Soluble macrophage-derived CD163 is a marker of disease activity and progression in early rheumatoid arthritis.

OBJECTIVES: To investigate the expression of the soluble form of the resident macrophage marker CD163 (sCD163) and its association with core parameters for disease activity, including radiographic progression in early rheumatoid arthritis (RA). METHODS: In a longitudinal sample set from early RA patients (n=34) we measured plasma levels of sCD163 at initiation of treatment and after 9 months of treatment and correlated levels with disease activity in 28 joints (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and total Sharp score (TSS). We also measured plasma levels of sCD163 in 55 healthy volunteers (HV) and in a transverse sample set of chronic (>8 years of disease) RA patients (n=24) and OA patients (n=24) with paired plasma and joint fluid. RESULTS: Early RA patients had significantly higher plasma levels of sCD163 (1.69mg/l (1.42-2.10)) (median (IQR)) at baseline than after 9 months of treatment (1.28mg/l (0.963-1.66), p=0.001), but not significantly changed compared with HV (1.66mg/l (1.22-2.02)). In early RA patients, baseline levels of sCD163, correlated with DAS28, CRP and ESR. Interestingly, sCD163 at 9 months was associated with radiographic progression (TSS) between year 0 and 5 (r=0.468, p=0.02). Levels of sCD163 were higher in RA patients, than in OA patients and higher in SF than in plasma. CONCLUSIONS: Plasma levels of macrophage derived sCD163 are associated with disease activity and predict radiographic progression in early RA patients, supporting that sCD163 may have a role as a biomarker of disease activity and that resident macrophages are important for joint destruction.