Apolipoprotein E Triggers Complement Activation in Joint Synovial Fluid of Rheumatoid Arthritis Patients by Binding C1q.

We identified apolipoprotein E (ApoE) as one of the proteins that are found in complex with complement component C4d in pooled synovial fluid of rheumatoid arthritis (RA) patients. Immobilized human ApoE activated both the classical and the alternative complement pathways. In contrast, ApoE in solution demonstrated an isoform-dependent inhibition of hemolysis and complement deposition at the level of sC5b-9. Using electron microscopy imaging, we confirmed that ApoE interacts differently with C1q depending on its context; surface-bound ApoE predominantly bound C1q globular heads, whereas ApoE in a solution favored the hinge/stalk region of C1q. As a model for the lipidated state of ApoE in lipoprotein particles, we incorporated ApoE into phosphatidylcholine/phosphatidylethanolamine liposomes and found that the presence of ApoE on liposomes increased deposition of C1q and C4b from serum when analyzed using flow cytometry. In addition, posttranslational modifications associated with RA, such as citrullination and oxidation, reduced C4b deposition, whereas carbamylation enhanced C4b deposition on immobilized ApoE. Posttranslational modification of ApoE did not alter C1q interaction but affected binding of complement inhibitors factor H and C4b-binding protein. This suggests that changed ability of C4b to deposit on modified ApoE may play an important role. Our data show that posttranslational modifications of ApoE alter its interactions with complement. Moreover, ApoE may play different roles in the body depending on its solubility, and in diseased states such as RA, deposited ApoE may induce local complement activation rather than exert its typical role of inhibition.

Secular trends of sustained remission in rheumatoid arthritis, a nationwide study in Sweden.

OBJECTIVES: The aim of this study of patients with RA in Sweden was to investigate secular trends in achieving sustained remission (SR), i.e. DAS28 <2.6 on at least two consecutive occasions and lasting for at least 6 months. METHODS: All adult RA patients registered in the Swedish Rheumatology Quality register through 2012, with at least three registered visits were eligible, a total of 29 084 patients. Year of symptom onset ranged from 1955, but for parts of the analysis only patients with symptom onset between 1994 and 2009 were studied. In total, 95% of patients fulfilled the ACR 1987 classification criteria for RA. Odds of reaching SR for each decade compared with the one before were calculated with logistic regression and individual years of symptom onset were compared with life table analysis. RESULTS: Of patients with symptom onset in the 1980s, 1990s and 2000s, 35.0, 43.0 and 45.6% reached SR, respectively (P < 0.001 for each increment), and the odds of SR were higher in every decade compared with the one before. The hazard ratio for reaching SR was 1.15 (95% CI 1.14, 1.15) for each year from 1994 to 2009 compared with the year before. Five years after symptom onset in 2009, 45.3% of patients had reached SR compared with 15.9% in 1999. CONCLUSION: There is a clear secular trend towards increased incidence of SR in patients with RA in Sweden. This trend most likely reflects earlier diagnosis and treatment start, and adherence to national and international guidelines recommending the treat to target approach.

Prevalence of sustained remission in rheumatoid arthritis: impact of criteria sets and disease duration, a Nationwide Study in Sweden.

Objectives: The aims of this national study in Sweden of patients with RA were to: examine the prevalence of sustained remission (SR), that is, remission lasting for at least 6 months; compare the prevalence of SR in patients with early RA and established RA; study the timing of onset of and time spent in SR; and study possible predictors of SR. Methods: Adult patients with RA included in the Swedish Rheumatology Quality registry were studied. The registry was searched for patients fulfilling remission criteria: DAS28-ESR, Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI) and ACR/EULAR remission for at least 6 months. Early RA was defined as symptom duration ⩽6 months at inclusion in the Swedish Rheumatology Quality. Results: Of 29 084 patients, 12 193 (41.9%) reached DAS28 SR at some time point during follow-up compared with 6445 (22.2%), 6199 (21.3%) and 5087 (17.5%) for CDAI, SDAI and ACR/EULAR SR, respectively. SR was more common in early RA (P < 0.001). The median time from symptom onset to SR was 1.9, 2.4, 2.4 and 2.5 years according to DAS28, CDAI, SDAI and ACR/EULAR criteria, respectively. Lower age, male sex and milder disease characteristics were associated with SR. Conclusion: The majority of patients in this nationwide study never reached SR. Patients with early RA are more likely to reach SR than patients with established RA.

Activation of Complement by Pigment Epithelium-Derived Factor in Rheumatoid Arthritis.

The aim of this study was to identify molecules that trigger complement activation in rheumatic joints. C4d, the final cleavage product of C4 activation, is found in the diseased joint and can bind covalently to complement-activating molecules. By using a highly specific Ab against a cleavage neoepitope in C4d, several molecules that were specifically bound to C4d were identified from pooled synovial fluid (SF) from four rheumatoid arthritis (RA) patients. One of these molecules, pigment epithelium-derived factor (PEDF), is a broadly expressed multifunctional member of the serine proteinase inhibitor family. Using ELISA, we confirmed the presence of various amounts of complexes between PEDF and C4d in the SF from 30 RA patients, whereas none were detected in SF from control subjects. Correlation analyses suggested that, in arthritis patients, C4d-PEDF complexes found in sera arise from the joints, as well as from other tissues, and levels of the complexes did not differ in sera of RA patients and healthy controls. When immobilized, recombinant PEDF expressed in eukaryotic cells activated the classical complement pathway but not the alternative or lectin pathways. C1q protein was demonstrated to bind immobilized PEDF, and PEDF was shown to bind to immobilized C1q, in particular its head regions, which are known to interact with other activators of the classical pathway. Our results call for further investigation into the role of PEDF in inflammatory processes in the joint, which, in combination with classical complement activation, appears to be part of a (patho-)physiologic response.

Immunogenicity and safety of pneumococcal vaccination in patients with systemic sclerosis.

Objective: To study the impact of disease and treatment with DMARDs on antibody response elicited by either pneumococcal conjugate vaccine (PCV13) or pneumococcal polysaccharide vaccine (PPV23) in patients with SSc. Methods: Forty-four SSc patients and 49 controls received a dose of either PCV13 or PPV23. Twelve patients were treated with DMARDs. Antibody levels to pneumococcal polysaccharides 6B and 23 F were measured before and 4-6 weeks after vaccination using ELISA. Antibody functionality was studied using opsonophagocytic assay performed on serotype 23 F. Results: Number of patients, percentage female and mean age (years) at vaccination were: 32, 94%, 57.5 years in SSc without DMARDs; 12, 100%, 55.5 years in SSc on DMARDs and 49, 63% and 50.6 years in controls. Post-vaccination antibody levels for both serotypes increased significantly in SSc without DMARDs and controls (P < 0.001), but in SSc on DMARDs only for 6B (P = 0.041). Compared with the other groups, patients with SSc receiving DMARDs had lower post-vaccination antibody levels for both serotypes. Opsonophagocytic assay increased significantly in all three groups. No significant difference in immunogenicity between PCV13 and PPV23 was seen. Conclusion: Pneumococcal vaccination using either PCV13 or PPV23 yielded satisfactory antibody response in SSc patients without DMARD treatment, but a lower response in patients treated with synthetic DMARDs. Type of pneumococcal vaccine (conjugate or polysaccharide) did not significantly influence antibody response. Trial registration: ClinicalTrials.gov, http://clinicaltrials.gov, NCT02240888.

Proteome-wide analysis and CXCL4 as a biomarker in systemic sclerosis.

BACKGROUND: Plasmacytoid dendritic cells have been implicated in the pathogenesis of systemic sclerosis through mechanisms beyond the previously suggested production of type I interferon. METHODS: We isolated plasmacytoid dendritic cells from healthy persons and from patients with systemic sclerosis who had distinct clinical phenotypes. We then performed proteome-wide analysis and validated these observations in five large cohorts of patients with systemic sclerosis. Next, we compared the results with those in patients with systemic lupus erythematosus, ankylosing spondylitis, and hepatic fibrosis. We correlated plasma levels of CXCL4 protein with features of systemic sclerosis and studied the direct effects of CXCL4 in vitro and in vivo. RESULTS: Proteome-wide analysis and validation showed that CXCL4 is the predominant protein secreted by plasmacytoid dendritic cells in systemic sclerosis, both in circulation and in skin. The mean (±SD) level of CXCL4 in patients with systemic sclerosis was 25,624±2652 pg per milliliter, which was significantly higher than the level in controls (92.5±77.9 pg per milliliter) and than the level in patients with systemic lupus erythematosus (1346±1011 pg per milliliter), ankylosing spondylitis (1368±1162 pg per milliliter), or liver fibrosis (1668±1263 pg per milliliter). CXCL4 levels correlated with skin and lung fibrosis and with pulmonary arterial hypertension. Among chemokines, only CXCL4 predicted the risk and progression of systemic sclerosis. In vitro, CXCL4 down-regulated expression of transcription factor FLI1, induced markers of endothelial-cell activation, and potentiated responses of toll-like receptors. In vivo, CXCL4 induced the influx of inflammatory cells and skin transcriptome changes, as in systemic sclerosis. CONCLUSIONS: Levels of CXCL4 were elevated in patients with systemic sclerosis and correlated with the presence and progression of complications, such as lung fibrosis and pulmonary arterial hypertension. (Funded by the Dutch Arthritis Association and others.).

Limited impact of fibromodulin deficiency on the development of experimental skin fibrosis.

Excessive production of collagen is the hallmark of fatal diseases of fibrosis such as systemic sclerosis. Overexpression of the proteoglycan fibromodulin (FMOD) has been associated with improved wound healing and scarless repair. In this study, we have investigated the consequences of FMOD deficiency on the development of experimental skin fibrosis. Using immunohistochemistry, we identified FMOD in both human and murine fibrotic skin. In the bleomycin model of skin fibrosis, FMOD(-/-) mice developed skin fibrosis to a similar degree compared to FMOD(+/+) mice. Analysis of skin ultrastructure using transmission electron microscopy revealed a significant reduction in collagen fibril diameter in FMOD(-/-) but not FMOD(+/+) mice following fibrosis. We conclude that the impact of FMOD deficiency on the development of experimental skin fibrosis is limited.

Circulating complexes between tumour necrosis factor-alpha and etanercept predict long-term efficacy of etanercept in juvenile idiopathic arthritis.

AIM: The relationship between tumour necrosis factor-alpha (TNF-α) and drug survival had not been studied in juvenile idiopathic arthritis (JIA), and there were no laboratory tests to predict the long-term efficacy of biological drugs for JIA. We studied whether serum levels of TNF-α, free or bound to etanercept, could predict long-term efficacy of etanercept in children with JIA. METHODS: We included 41 biologic-naïve patients with JIA who started treatment with etanercept at Skåne University Hospital between 1999 and 2010. Serum taken at the start of treatment and at the six-week follow-up were analysed for TNF-α and the long-term efficacy of etanercept was assessed using the drug survival time. RESULTS: Levels of TNF-α increased significantly at the six-week follow-up, and this was almost exclusively comprised of TNF-α in complex with etanercept. The increase in TNF-α showed a dose-dependent correlation to long-term drug survival (p < 0.01). CONCLUSION: Increasing levels of circulating TNF-α at treatment initiation predicted long-term efficacy of etanercept in children with JIA, which may have been due to different pathophysiological mechanisms of inflammation. Our result may provide a helpful clinical tool, as high levels of circulating TNF-α/etanercept complexes could be used as a marker for the long-term efficacy of etanercept.

Novel cartilage oligomeric matrix protein (COMP) neoepitopes identified in synovial fluids from patients with joint diseases using affinity chromatography and mass spectrometry.

To identify patients at risk for progressive joint damage, there is a need for early diagnostic tools to detect molecular events leading to cartilage destruction. Isolation and characterization of distinct cartilage oligomeric matrix protein (COMP) fragments derived from cartilage and released into synovial fluid will allow discrimination between different pathological conditions and monitoring of disease progression. Early detection of disease and processes in the tissue as well as an understanding of the pathologic mechanisms will also open the way for novel treatment strategies. Disease-specific COMP fragments were isolated by affinity chromatography of synovial fluids from patients with rheumatoid arthritis, osteoarthritis, or acute trauma. Enriched COMP fragments were separated by SDSPAGE followed by in-gel digestion and mass spectrometric identification and characterization.Using the enzymes trypsin, chymotrypsin, and Asp-N for the digestions, an extensive analysis of the enriched fragments could be accomplished. Twelve different neoepitopes were identified and characterized within the enriched COMP fragments. For one of the neoepitopes, Ser77, an inhibition ELISA was developed. This ELISA quantifies COMP fragments clearly distinguishable from total COMP. Furthermore, fragments containing the neoepitope Ser77 were released into the culture medium of cytokine (TNF-α and IL-6/soluble IL-6 receptor)-stimulated human cartilage explants. The identified neoepitopes provide a complement to the currently available commercial assays for cartilage markers. Through neoepitope assays, tools to pinpoint disease progression, evaluation methods for therapy, and means to elucidate disease mechanisms will be provided.

PRELP protein inhibits the formation of the complement membrane attack complex.

PRELP is a 58-kDa proteoglycan found in a variety of extracellular matrices, including cartilage and at several basement membranes. In rheumatoid arthritis (RA), the cartilage tissue is destroyed and fragmented molecules, including PRELP, are released into the synovial fluid where they may interact with components of the complement system. In a previous study, PRELP was found to interact with the complement inhibitor C4b-binding protein, which was suggested to locally down-regulate complement activation in joints during RA. Here we show that PRELP directly inhibits all pathways of complement by binding C9 and thereby prevents the formation of the membrane attack complex (MAC). PRELP does not interfere with the interaction between C9 and already formed C5b-8, but inhibits C9 polymerization thereby preventing formation of the lytic pore. The alternative pathway is moreover inhibited already at the level of C3-convertase formation due to an interaction between PRELP and C3. This suggests that PRELP may down-regulate complement attack at basement membranes and on damaged cartilage and therefore limit pathological complement activation in inflammatory disease such as RA. The net outcome of PRELP-mediated complement inhibition will highly depend on the local concentration of other complement modulating molecules as well as on the local concentration of available complement proteins.

Heavy chains of inter alpha inhibitor (IαI) inhibit the human complement system at early stages of the cascade.

Inter alpha inhibitor (IαI) is an abundant serum protein consisting of three polypeptides: two heavy chains (HC1 and HC2) and bikunin, a broad-specificity Kunitz-type proteinase inhibitor. The complex is covalently held together by chondroitin sulfate but during inflammation IαI may interact with TNF-stimulated gene 6 protein (TSG-6), which supports transesterification of heavy chains to hyaluronan. Recently, IαI was shown to inhibit mouse complement in vivo and to protect from complement-mediated lung injury but the mechanism of such activity was not elucidated. Using human serum depleted from IαI, we found that IαI is not an essential human complement inhibitor as was reported for mice and that such serum has unaltered hemolytic activity. However, purified human IαI inhibited classical, lectin and alternative complement pathways in vitro when added in excess to human serum. The inhibitory activity was dependent on heavy chains but not bikunin and detected at the level of initiating molecules (MBL, properdin) in the lectin/alternative pathways or C4b in the classical pathway. Furthermore, IαI affected formation and assembly of the C1 complex and prevented assembly of the classical pathway C3-convertase. Presence and putative interactions with TSG-6 did not affect the ability of IαI to inhibit complement thus implicating IαI as a potentially important complement inhibitor once enriched onto hyaluronan moieties in the course of local inflammatory processes. In support of this, we found a correlation between IαI/HC-containing proteins and hemolytic activity of synovial fluid from patients suffering from rheumatoid arthritis.

Genetic studies on components of the Wnt signalling pathway and the severity of joint destruction in rheumatoid arthritis.

BACKGROUND: Progression of joint destruction in rheumatoid arthritis (RA) is partly heritable; knowledge of genetic factors may increase our understanding of the mechanisms underlying joint destruction. The activity of the Wnt/ß-catenin pathway influences osteoblast differentiation. Dickkopf-1 (Dkk-1) and sclerostin (Sost) are negative regulators and lipoprotein receptor-related protein-5 (LRP-5) and Kremen-1 are transmembrane receptors involved in this pathway. OBJECTIVE: To study variants in the genes encoding these proteins in relation to progression of joint destruction. METHODS: 1418 patients with RA of four cohorts with 4885 sets of hands and feet x-rays were studied. Explorative analyses were performed on 600 patients with RA from Leiden on single nucleotide polymorphisms (SNPs) tagging Dkk-1, Sost, Kremen-1 and LRP-5. SNPs significantly associating with joint damage progression were subsequently genotyped in cohorts from Groningen (NL), Sheffield (UK) and Lund (Sweden). Data were summarised in meta-analyses. Serum levels of functional Dkk-1 and sclerostin were measured and studied in relation to genotypes. RESULTS: In the first cohort, six Dkk-1, three Sost, one Kremen-1 and 10 LRP-5 SNPs were significantly associated with radiological progression of joint destruction. Three Dkk-1 SNPs were associated significantly with progression of joint damage in the meta-analysis, also after correction for multiple testing (rs1896368, rs1896367 and rs1528873). Two Sost SNPs tended to significance (rs4792909 and rs6503475, p=0.07 after false discovery rate correction). Gene-gene interactions between SNPs on Dkk-1 and Sost were seen. Serum levels of Dkk-1 were significantly correlated with the genotypes in rs1896368 (p=0.02). CONCLUSIONS: Patients with RA carrying risk alleles of genetic variants in Dkk-1 have higher serum levels of functional Dkk-1 and more progressive joint destruction over time.

Early increase in serum-COMP is associated with joint damage progression over the first five years in patients with rheumatoid arthritis.

BACKGROUND: Currently available biomarkers for the early tissue process leading to joint damage in rheumatoid arthritis are insufficient and lack prognostic accuracy, possibly a result of variable activity of the disease over time. This study represents a novel approach to detect an altered activity of the disease process detected as increasing serum-COMP levels over a short time and whether this would correlate with joint damage progression over the first 5 years of disease. METHODS: In all, 349 patients from the Swedish BARFOT early RA study were examined. Serum-COMP was analysed by ELISA at diagnosis and after 3 months. Based on changes in serum-COMP levels, three subgroups of patients were defined: those with unchanged levels (change ≤ 20%) (N=142), decreasing levels (> 20%) (N=173) and increasing levels (> 20%) (N=34). Radiographs of hands and feet were obtained at inclusion, after 1, 2 and 5 years and scored according to Sharp van der Heijde (SHS). Radiographic progression was defined as increase in SHS by ≥5.8. RESULTS: The group of patients with increasing COMP levels showed higher median change in total SHS and erosion scores at 1, 2 and 5 year follow-up compared with the groups with stable or decreasing COMP levels. Furthermore, the odds ratio of radiographic progression was 2.8 (95% CI 1.26-6.38) for patients with increasing COMP levels vs. patients with unchanged levels.The group of patients with increasing COMP levels had higher ESR at inclusion but there were no baseline differences between the groups for age, gender, disease duration, disease activity (DAS28), function (HAQ), CRP, nor presence of rheumatoid factor or anti-CCP. Importantly, neither did changes over the 3-month period in DAS28, HAQ, ESR nor CRP differ between the groups and these variables did not correlate to joint damage progression. CONCLUSION: Increasing serum-COMP levels between diagnosis and the subsequent 3 months in patients with early RA represents a novel indicator of an activated destructive process in the joint and is a promising tool to identify patients with significant joint damage progression during a 5-year period.

Relationships amongst osteoarthritis biomarkers, dynamic knee joint load, and exercise: results from a randomized controlled pilot study.

BACKGROUND: Little is known about the relationships of circulating levels of biomarkers of cartilage degradation with biomechanical outcomes relevant to knee osteoarthritis (OA) or biomarker changes following non-pharmacological interventions. The objectives of this exploratory, pilot study were to: 1) examine relationships between biomarkers of articular cartilage degradation and synthesis with measures of knee joint load during walking, and 2) examine changes in these biomarkers following 10 weeks of strengthening exercises. METHODS: Seventeen (8 male, 9 female; 66.1 +/- 11.3 years of age) individuals with radiographically-confirmed medial tibiofemoral OA participated. All participants underwent a baseline testing session where serum and urine samples were collected, followed by a three-dimensional motion analysis. Motion analysis was used to calculate the external knee adduction moment (KAM) peak value and impulse. Following baseline testing, participants were randomized to either 10 weeks of: 1) physiotherapist-supervised lower limb muscle strengthening exercises, or 2) no exercises (control). Identical follow-up testing was conducted 11 weeks after baseline. Biomarkers included: urinary C-telopeptide of type II collagen (uCTX-II) and type II collagen cleavage neoepitope (uC2C), serum cartilage oligomeric matrix protein (sCOMP), serum hyaluronic acid (sHA) and serum C-propeptide of type II procollagen (sCPII). Linear regression analysis was used to examine relationships between measures of the KAM and biomarker concentrations as baseline, as well as between-group differences following the intervention. RESULTS: KAM impulse predicted significant variation in uCTX-II levels at baseline (p = 0.04), though not when controlling for disease severity and walking speed (p = 0.33). KAM impulse explained significant variation in the ratio uCTX-II;sCPII even when controlling for additional variables (p = 0.04). Following the intervention, changes in sCOMP were significantly greater in the exercise group compared to controls (p = 0.04). On average those in the control group experienced a slight increase in sCOMP and uCTX-II, while those in the exercise group experienced a reduction. No other significant findings were observed. CONCLUSIONS: This research provides initial evidence of a potential relationship between uCTX-II and knee joint load measures in patients with medial tibiofemoral knee OA. However, this relationship became non-significant after controlling for disease severity and walking speed, suggesting further research is necessary. It also appears that sCOMP is amenable to change following a strengthening intervention, suggesting a potential beneficial role of exercise on cartilage structure. TRIAL REGISTRATION: Clinicaltrials.gov NCT01241812.

Cardiovascular disease risk in early rheumatoid arthritis: the impact of cartilage oligomeric matrix protein (COMP) and disease activity.

BACKGROUND: To investigate whether baseline serum cartilage oligomeric matrix protein (COMP), patient characteristics, traditional cardiovascular disease (CVD) risk factors and disease activity over time predict CVD, in early rheumatoid arthritis (RA). METHODS: This study included patients with early RA (< 12 months disease duration) (n = 233) recruited 1995-2005. Potential predictors of CVD and coronary artery disease (CAD) were assessed using Cox regression. RESULTS: A first ever diagnosis of CVD occurred in 70 patients, and CAD in 52. Age, sex, hypertension and diabetes predicted CVD and CAD. COMP was associated with increased risk of CVD and CAD [crude hazard ratios (HRs) per SD 1.45; 95% CI 1.17-1.80 and 1.51; 95% CI 1.18-1.92, respectively]. When adjusted for age, sex, hypertension, diabetes and ESR, results where similar but did not reach significance [HRs 1.32, 95% CI 0.99-1.74 and 1.35, 95% CI 0.99-1.86]. Baseline disease activity did not independently predict CVD. High DAS28 (> 5.1) at two years was associated with increased risk of subsequent CVD [adjusted HR 2.58; 95% CI 1.10-6.04] and CAD. ESR and CRP at two years as well as cumulative disease activity over 2 years independently predicted CVD and CAD. CONCLUSION: COMP may be a novel predictor of CVD and CAD in RA. Active disease two years after RA diagnosis, as well as cumulative disease activity, was associated with increased risk of CVD and CAD, independent of traditional CVD risk factors. Awareness of the particularly increased CVD risk among difficult to treat patients is important in order to further reduce CVD in RA.

Extracellular matrix alterations and acute inflammation; developing in parallel during early induction of pulmonary fibrosis.

Pulmonary fibrosis is a hallmark of several systemic diseases such as systemic sclerosis. Initiation and early development is not well characterized, as initiation usually is unnoticed in patients, yet fibrosis has been considered a late event, occurring after an inflammatory phase. By utilizing an animal model, the starting point can be defined and the initiation process and early development thoroughly investigated. To investigate these processes from a systemic perspective, we choose a systemic administration route, instead of the more commonly used local administration. The aim of this work was to study the initiation of pulmonary fibrosis in an animal model and to investigate early alterations in connective tissue, cell turnover and acute immune response in lung parenchyma. Animals were injected subcutaneously with bleomycin, three times a week (w) for 1-4w (controls received saline). Total collagen was histologically assessed by Picro Sirius Red and Masson's Trichrome, collagen production by antibodies directed against N-terminal of procollagens I and III, proliferation by labeling with proliferating cell nuclear antigen, apoptosis by TUNEL and innate immunity by detecting neutrophils and macrophages. Total collagen was significantly increased at 1, 2 and 4w compared with controls. Procollagen I, was increased at 1w and remained increased, whereas procollagen III-staining was increased at 2w, compared with controls. Myofibroblasts were increased at all times as were proliferation, whereas apoptosis was increased from 2w. Neutrophils peaked at 1w (2779±820 cells/mm²) and gradually decreased, whereas macrophages peaked at 2w (135±29 cells/mm²). Subcutaneously administered bleomycin induces rapid alterations in connective tissue and cell turnover, suggesting a plasticity of the connective tissue. A transient neutrophilia is detected and increased number of macrophages likely represents a clearance process of said neutrophils. The study suggests fibrosis initiation and acute inflammation to occur in parallel in this model.

Increased serum COMP predicts mortality in SSc: results from a longitudinal study of interstitial lung disease.

OBJECTIVES: COMP is a regulator of assembly and maintenance of the fibrillar collagen I and II networks. Serum COMP reflects skin fibrosis in SSc. The purpose of this study was to examine whether serum COMP reflects fibrotic lung involvement in SSc patients and to study if serum COMP predicts mortality. METHODS: Three overlapping cohorts of 244 SSc patients were studied. Two hundred and eighteen patients were included to study survival, 80 patients to study longitudinal changes of pulmonary function tests and 64 to study pulmonary involvement assessed by high-resolution CT (HRCT). Serum COMP was measured by ELISA. Skin involvement was assessed with the modified Rodnan skin score (mRSS). Data about survival were obtained from the central population registry. RESULTS: Serum COMP measured within 5 years after the first non-Raynaud's manifestation was a predictor of death, and crude mortality increased by 6% for each COMP unit elevation. Serum COMP levels >15 U/l were associated with a 3.13-fold (95% CI 1.73, 5.64; P < 0.001) increased risk of death. During the first year of follow-up serum COMP and vital capacity (VC) changed inversely (r(s) = -0.32; P = 0.005), but there were no correlations between baseline serum COMP and concurrent findings by spirometry or HRCT. CONCLUSION: Serum COMP early in disease is a predictor of mortality in SSc patients. Serum COMP changes in parallel with lung fibrosis as measured by VC, but the release from fibrotic skin possibly obscures the influx from the lungs and therefore serum COMP seems to have little utility as a marker of lung fibrosis.

Sick leave in patients with ankylosing spondylitis before and after anti-TNF therapy: a population-based cohort study.

OBJECTIVE: To study levels of sick leave and disability pension before and after TNF-antagonist therapy in AS patients. METHODS: Using the population-based South Swedish Arthritis Treatment Group register, we identified 139 AS patients (aged 18-58 years, 78% men), who between January 2002 and December 2008 started their first treatment with adalimumab, etanercept or infliximab. We linked data to the payment register by the Swedish Social Insurance Agency and calculated the proportion on sick leave in 30-day intervals from 12 months before treatment start until 12 months after. For each AS patient, we randomly selected four subjects from the general population matched for age, sex and area of residence. RESULTS: One to 3 months before treatment, an average of 24% of AS patients were on sick leave. During the first 6 months after treatment start, this fraction dropped to 15%, and further declined to 12% at 12 months (P < 0.001). Comparing AS patients with the general population, the relative risk of being on sick leave 3 months before treatment, treatment start and 12 months after treatment start was 8.0 (95% CI 4.6, 13.9), 9.2 (95% CI 5.4, 15.7) and 4.0 (95% CI 2.1, 6.3), respectively. The decrease in sick leave was not substantially offset by changes in disability pension. CONCLUSION: There is a decline in sick leave during the first 12 months after initiation of TNF-antagonist treatment in AS patients not explained by societal factors or secular trends. The proportion of AS patients on disability pension remained unchanged during the observation period.

Antibody response is reduced following vaccination with 7-valent conjugate pneumococcal vaccine in adult methotrexate-treated patients with established arthritis, but not those treated with tumor necrosis factor inhibitors.

OBJECTIVE: To study the influence of antiinflammatory treatments, including methotrexate (MTX) and tumor necrosis factor (TNF) inhibitors, on antibody response following vaccination using a 7-valent conjugate pneumococcal vaccine in adult patients with established arthritis. METHODS: Patients with rheumatoid arthritis (RA) or spondylarthropathy (SpA) (including psoriatic arthritis) were vaccinated (n = 505). All patients were stratified into 6 prespecified groups based on diagnosis and treatment (RA patients receiving MTX, RA patients receiving anti-TNF agents and MTX, RA patients receiving TNF inhibitors as monotherapy, SpA patients receiving anti-TNF agents and MTX, SpA patients receiving TNF inhibitors as monotherapy, and SpA patients receiving nonsteroidal antiinflammatory drugs [NSAIDs] and/or analgesics). SpA patients receiving only NSAIDs/analgesics served as a control group. All patients received 1 dose (0.5 ml) of vaccine intramuscularly. Levels of IgG antibodies against 23F and 6B serotypes were measured at vaccination and at 4-6 weeks following vaccination, using standardized enzyme-linked immunosorbent assays. RESULTS: Positive antibody response was defined as an antibody response ratio (ARR) (i.e., ratio of post- to prevaccination antibody levels) of ≥2. The ARR differed significantly between the groups. A better ARR was seen among patients in the control group compared to those in groups treated with MTX or MTX in combination with TNF inhibitors. Among patients treated with TNF inhibitors as monotherapy, ARRs for both serotypes were lower numerically, but were not significantly different, compared to those in controls. Ongoing MTX treatment was predictive of reduced response (odds ratio 0.41 [95% confidence interval 0.24-0.68], P = 0.001). Higher age was associated with impaired positive antibody response. Concomitant prednisolone treatment elicited better positive antibody response in patients with RA. CONCLUSION: Treatment with MTX and higher age were predictive of an impaired antibody response to the 7-valent conjugate pneumococcal vaccine in this cohort of patients with chronic arthritis. TNF inhibitors did not significantly affect antibody responses.