Exhaled Nitric Oxide Reflects the Immune Reactions of the Airways in Early Rheumatoid Arthritis.

Patients with rheumatoid arthritis (RA) have altered levels of exhaled nitric oxide (NO) compared with healthy controls. Here, we investigated whether the clinical features of and immunological factors in RA pathogenesis could be linked to the NO lung dynamics in early disease. A total of 44 patients with early RA and anti-citrullinated peptide antibodies (ACPAs), specified as cyclic citrullinated peptide 2 (CCP2), were included. Their exhaled NO levels were measured, and the alveolar concentration, the airway compartment diffusing capacity and the airway wall concentration of NO were estimated using the Högman-Meriläinen algorithm. The disease activity was measured using the Disease Activity Score for 28 joints. Serum samples were analysed for anti-CCP2, rheumatoid factor, free secretory component, secretory component containing ACPAs, antibodies against Porphyromonas gingivalis (Rgp) and total levels of IgA, IgA1 and IgA2. Significant negative correlations were found between the airway wall concentration of NO and the number of swollen joints (Rho -0.48, p = 0.004), between the airway wall concentration of NO and IgA rheumatoid factor (Rho -0.41, p = 0.017), between the alveolar concentration and free secretory component (Rho -0.35, p = 0.023) and between the alveolar concentration and C-reactive protein (Rho -0.36, p = 0.016), but none were found for anti-CCP2, IgM rheumatoid factor or the anti-Rgp levels. In conclusion, altered NO levels, particularly its production in the airway walls, may have a role in the pathogenesis of ACPA-positive RA.

Serum calprotectin correlates more strongly with inflammation and disease activity in ACPA positive than ACPA negative rheumatoid arthritis.

OBJECTIVES: The aim of the present study was to evaluate performance of serum and synovial fluid levels of the granulocyte protein calprotectin as inflammatory biomarker in rheumatoid arthritis (RA) patients with knee synovitis. METHODS: 76 RA patients with ongoing knee synovitis were included. Data on disease activity score with 28 joints and their subcomponents and radiological destruction of the affected knee were collected. White blood cell count, C-reactive protein, anti-citrullinated peptide antibodies (ACPA) against cyclic citrullinated peptide version 2 (anti-CCP2), IgM rheumatoid factor (RF) and calprotectin were analysed in parallel in circulation and in synovial fluid (SF). Counts of polynuclear and mononuclear cells were measured in SF. RESULTS: Serum (S) calprotectin correlated stronger than SF-calprotectin with inflammatory markers and disease activity. Instead, SF-calprotectin showed a strong correlation to SF counts of white blood cells, and especially to polymorphonuclear cell counts (Spearman's rho = 0.72, p< 0.001). S-calprotectin showed markedly stronger correlation with inflammatory markers and disease activity in ACPA positive as compared with ACPA negative RA patients; a similar difference was observed for patients with and without IgM RF. CONCLUSION: The particularly strong association between circulating calprotectin and inflammation in ACPA positive RA is a new argument for a specific role for polymorphonuclear granulocytes/neutrophils in this RA subset. Measurement of calprotectin in SF does not convey any additional benefit compared with measurement in the circulation in RA patients with knee synovitis.

Exhaled nitric oxide in early rheumatoid arthritis and effects of methotrexate treatment.

Patients with established rheumatoid arthritis (RA) and disease modifying treatments have lower nitric oxide (NO) levels in the alveolar compartment (CANO) and in the airway wall (CawNO), but also higher diffusion capacities for NO in the airways (DawNO) compared to matched controls. The aim of the present study was to investigate the NO lung dynamics in patients with recent onset RA before and after immune suppression with methotrexate therapy. Patients with early RA and antibodies against anticitrullinated peptides (ACPA) were recruited. Measurement of exhaled NO and inflammatory markers in serum were performed. Clinical disease activity was evaluated with Disease Activity Score for 28 joints. Healthy individuals were used as matched controls. Data are presented as median (lower quartile, upper quartile) values. RA patients (n = 44) had lower exhaled NO (FENO50) 16 (10-24) ppb compared to controls 21 (15, 29) ppb, p = 0.013. In NO-dynamics, CANO was lower in RA patients 1.6 (1.0, 2.2) ppb compared to the control subjects 2.3 (1.3, 3.1) ppb, p = 0.007. CawNO was also lower in the RA patients 55 (24, 106) ppb compared to control subjects 124 (110, 170) ppb, p < 0.001, but DawNO was higher 17 (8, 30) mL/s and 9 (5, 11) mL/s respectively, p < 0.001. Methotrexate treatment for three months reduced disease activity, but did not change the NO dynamics. In conclusion, the altered NO dynamics of the lung in ACPA-positive RA patients are already present in the early stages of the disease before any treatments and do not change after methotrexate therapy suggesting a role in the pathogenesis.

Extramucosal Formation and Prognostic Value of Secretory Antibodies in Rheumatoid Arthritis.

OBJECTIVE: To investigate levels and possible extramucosal formation of secretory Ig, including anti-citrullinated protein antibodies (ACPAs), in rheumatoid arthritis (RA). METHODS: Three patient groups were studied: 1) ACPA-positive patients with musculoskeletal pain without clinical arthritis, 2) patients with recent-onset RA, and 3) patients with established RA. In baseline serum samples (groups 1 and 2) and paired synovial fluid samples (group 3), we analyzed total secretory IgA, total secretory IgM, free secretory component (SC), and SC-containing ACPA. Extramucosal formation of SC-containing ACPA was investigated by preincubating RA sera and affinity-purified ACPA with recombinant free SC. RESULTS: Compared to healthy controls, serum levels of total secretory IgA and total secretory IgM were increased both in patients with early RA and at-risk patients (P < 0.05). Patients with early RA with elevated total secretory Ig had significantly higher disease activity during the 3-year follow-up period compared to those without increased levels. At-risk patients who developed arthritis during follow-up (39 of 82) had higher baseline total secretory IgA levels compared to those who did not (P = 0.041). In established RA, total secretory IgA and total secretory IgM levels were higher in serum than in synovial fluid (P < 0.0001), but SC-containing ACPAs adjusted for total secretory Ig concentration were higher in synovial fluid (P < 0.0001). Preincubation with recombinant free SC yielded increased SC-containing ACPA reactivity in sera as well as in affinity-purified IgA and IgM ACPA preparations. CONCLUSION: Circulating secretory Ig are elevated before and at RA onset. In the presence of free SC, secretory Ig may form outside the mucosa, and SC-containing ACPAs are enriched in RA joints. These findings shed important new light on the mucosal connection in RA development.

Number of individual ACPA reactivities in synovial fluid immune complexes, but not serum anti-CCP2 levels, associate with inflammation and joint destruction in rheumatoid arthritis.

INTRODUCTION: Individual patients with rheumatoid arthritis (RA) show divergent specific anti-citrullinated protein/peptide antibodies (ACPA) patterns, but hitherto no individual ACPA specificity has consistently been linked to RA pathogenesis. ACPA are also implicated in immune complexes (IC)-associated joint pathology, but until now, there has been no method to investigate the role of individual ACPA in RA IC formation and IC-associated pathogenesis. METHODS: We have developed a new technique based on IC binding to C1q-coated magnetic beads to purify and solubilise circulating IC in sera and synovial fluids (SF) from 77 patients with RA. This was combined with measurement of 19 individual ACPA in serum, SF and in the IC fractions from serum and SF. We investigated whether occurrence of individual ACPA as well as number of ACPA in these compartments was related to clinical and laboratory measures of disease activity and inflammation. RESULTS: The majority of individual ACPA reactivities were enriched in SF as compared with in serum, and levels of ACPA in IC were regulated independently of levels in serum and SF. No individual ACPA reactivity in any compartment showed a dominating association to clinical and laboratory measures of disease activity and severity. Instead, the number of individual ACPA reactivities in the IC fraction from SF associated with a number of markers of joint destruction and inflammation. CONCLUSIONS: Our data highlight the polyclonality of ACPA in joint IC and the possibility that a broad ACPA repertoire in synovial fluid IC might drive the local inflammatory and matrix-degrading processes in joints, in analogy with antibody-induced rodent arthritis models.

Altered levels of exhaled nitric oxide in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disorder characterized by bone and joint destruction, but other organ systems can also be involved. Recent studies have suggested that the disease may start in the lungs. Exhaled nitric oxide (FENO) is a marker of inflammation. The aims of the study were to compare the NO parameters between subjects with RA and healthy control subjects, and to examine whether the NO parameters correlated with lung function and disease activity in the subjects with RA. METHODS: Subjects with RA (n = 35) were recruited during their regular outpatient visits to the rheumatology department. The nitric oxide (NO) parameters: alveolar NO concentration (CANO), airway compartment diffusing capacity of NO (DawNO), and tissue concentration of NO in the airway wall (CawNO), were algorithmically estimated. Healthy subjects (n = 35) matched by age, gender and height were used as controls. Data are given in median, (quartile 25, 75). Wilcoxon Matched Pairs test was used for group comparisons. Mann-Whitney U test was used to make comparisons between any two groups and for pairwise comparisons. Correlations were tested with Spearman rank order correlation. RESULTS: CANO was significantly lower in the RA subjects compared with healthy subjects; 1.1 (0.5, 1.8) ppb versus 2.4 (2.0, 3.0) ppb, (p < 0.001). CawNO was significantly lower in the RA subjects with 51 (22, 87) ppb versus 120 (76, 162) ppb in the control group. DawNO was significantly higher at 25 (15, 36) mL/s in the RA group versus the control group's 7.7 (5.3, 10.7) mL/s. CONCLUSIONS: There are significant differences between subjects with RA and matched healthy control subjects regarding the exhaled NO parameters. It is unclear if this can be explained by the pathogenesis of RA, consequences of long-term disease, and/or due to drug treatment.

Seasonal variations of urate in a Swedish adult population.

Seasonality in the incidence and prevalence of gout has previously been reported but the cause of this seasonality in gout is not explained. The aim of this study was to evaluate possible seasonal variations of urate in a large unselected Swedish adult population. We analyzed 170,915 urate test results from patients at a tertiary care hospital between 2000 and 2016. The results were divided according to sex and sampling month of the year. The median urate values were overall higher in males compared to females and both males and females had peak urate concentrations in the summer months (June-August). There is a seasonal pattern for urate concentrations in a large Swedish population similar to the previously reported seasonality for gout. This may be clinically important and could contribute to the circannual variation of gout. The seasonal pattern should be recognized when evaluating patient results both in clinical practice and in research studies.

Active Rheumatoid Arthritis in Central Africa: A Comparative Study Between Sudan and Sweden.

OBJECTIVE: To compare clinical characteristics and treatment between simultaneously investigated Sudanese and Swedish outpatients with rheumatoid arthritis (RA). METHODS: Outpatients with RA from Sudan (n = 281) and Sweden (n = 542) diagnosed according to the 1987 American College of Rheumatology criteria were recruited between December 2008 and September 2010 and compared concerning clinical presentation, treatment, and laboratory findings, including immunoglobulin M with rheumatoid factor (IgM-RF). RESULTS: Sudanese patients had lower inclusion age (median 49 vs 68 yrs), disease duration (48 vs 107 mos), and disease onset age (43 vs 56 yrs) as compared with Swedish patients (p < 0.0001 for all). When stratified concerning the age of inclusion, Swedish patients between 41-50 years had, however, a significantly lower age of onset, with a similar trend for all age groups above 30 years. The female preponderance was higher among Sudanese patients (89.3% vs 72.5%, p < 0.0001), and smoking was nonexistent among Sudanese female patients (p < 0.0001). Erythrocyte sedimentation rate levels and number of tender joints were significantly higher among Sudanese patients. The proportion of IgM-RF positivity was lower among Sudanese patients with RA (52.4% vs 75.5%, p < 0.0001). Higher proportions of Sudanese patients with RA were treated with methotrexate (MTX) and disease-modifying antirheumatic drug combinations, but none of them used biologics. Sudanese patients used lower doses of MTX and sulfasalazine (p < 0.0001) and higher doses of prednisolone (p < 0.0001) than Swedish patients. CONCLUSION: Sudanese patients with RA have significantly higher disease activity and are often IgM-RF-seronegative. Together with reports from Uganda and Cameroon, our data indicate a cluster of highly active and often seronegative RA in central Africa.

Cathepsin S and cathepsin L in serum and synovial fluid in rheumatoid arthritis with and without autoantibodies.

OBJECTIVES: Cathepsin S and cathepsin L are endosomal proteolytic enzymes involved in the degradation of extracellular matrixes, angiogenesis and antigen presentation. Cathepsins could thus play several roles in the disease process of RA. The aim of this study was to examine differences in cathepsin S and cathepsin L levels in serum and SF of RA patients with and without ACPA and RF. METHODS: In this study 121 patients with RA and clinical signs of knee synovitis were recruited. Patient characteristics were collected and matched samples of serum and SF were analysed for cathepsin S, cathepsin L, ACPA, IgA and IgM RF, CRP and MMP3. RESULTS: SF levels of cathepsin L, cathepsin S and MMP3 were significantly higher than in serum. Serum levels of both cathepsins were significantly higher in patients with ACPA, IgM-RF and IgA-RF compared with patients without these antibodies. SF levels of both cathepsins correlated with DAS28 and CRP in ACPA- and RF-positive but not in seronegative patients. CONCLUSION: The differences in cathepsin S and cathepsin L between RA patients with and without autoantibodies indicate that these cathepsins have a specific role in the disease process of seropositive RA. In this phenotype, cathepsin serum levels may reflect the autoimmune activity, whereas the levels in SF may reflect the local inflammatory and matrix degrading process in the joint.

Outcome predictors of intra-articular glucocorticoid treatment for knee synovitis in patients with rheumatoid arthritis - a prospective cohort study.

INTRODUCTION: Intra-articular glucocorticoid treatment (IAGC) is widely used for symptom relief in arthritis. However, knowledge of factors predicting treatment outcome is limited. The aim of the present study was to identify response predictors of IAGC for knee synovitis in patients with rheumatoid arthritis (RA). METHODS: In this study 121 RA patients with synovitis of the knee were treated with intra-articular injections of 20 mg triamcinolone hexacetonide. They were followed for six months and the rate of clinical relapse was studied. Non-responders (relapse within 6 months) and responders were compared regarding patient characteristics and knee joint damage as determined by the Larsen-Dale index. In addition, matched samples of serum and synovial fluid were analysed for factors reflecting the inflammatory process (C-reactive protein, interleukin 6, tumour necrosis factor alpha, vascular endothelial growth factor), joint tissue turnover (cartilage oligomeric matrix protein, metalloproteinase 3), and autoimmunity (antinuclear antibodies, antibodies against citrullinated peptides, rheumatoid factor). RESULTS: During the observation period, 48 knees relapsed (40%). Non-responders had more radiographic joint damage than responders (P = 0.002) and the pre-treatment vascular endothelial growth factor (VEGF) level in synovial fluid was significantly higher in non-responders (P = 0.002). CONCLUSIONS: Joint destruction is associated with poor outcome of IAGC for knee synovitis in RA. In addition, higher levels of VEGF in synovial fluid are found in non-responders, suggesting that locally produced VEGF is a biomarker for recurrence of synovial hyperplasia and the risk for arthritis relapse.

Importance of immobilization after intraarticular glucocorticoid treatment for elbow synovitis: a randomized controlled study.

OBJECTIVE: To investigate whether better treatment results might be achieved with postinjection rest following intraarticular glucocorticoid treatment for elbow synovitis. METHODS: Ninety patients with rheumatoid arthritis and elbow synovitis were treated with 20 mg of intraarticular triamcinolone hexacetonide and randomized to either a 48-hour immobilization in a triangular sling (n = 46) or to normal activity without restrictions (n = 44). The primary end point was relapse of synovitis. In addition, pain, function according to a self-assessment questionnaire (the Patient Rated Elbow Evaluation), and range of movement were followed for 6 months. RESULTS: Thirteen relapses occurred in the rest group and 8 in the active group (results not significant). The secondary measures showed no statistically significant differences between the groups. CONCLUSION: Immobilization procedures do not improve the outcome of intraarticular glucocorticoid therapy for elbow synovitis. In future guidelines for such treatment of the upper extremity, normal activity after the injection should be recommended.