High CCL18/PARC expression in articular cartilage and synovial tissue of patients with rheumatoid arthritis

OBJECTIVE: We studied the role of CCL18/pulmonary and activation-regulated chemokine (PARC) in rheumatoid arthritis (RA). METHODS: Human cartilage tissues and synovial membranes were obtained from patients with RA and with osteoarthritis (OA). Sera samples were obtained from RA patients, OA patients, healthy controls, and patients with flu, and synovial fluid (SF) from patients with RA and OA. Real-time PCR was performed with RNA from cartilage samples. Immunohistochemical analysis of CCL18/PARC was done with RA and OA cartilage and synovial tissue. Levels of CCL18/PARC in serum and SF were evaluated by ELISA. RESULTS: CCL18/PARC mRNA was expressed at significantly higher levels in RA cartilage than in OA (p = 0.0001) and control (p < 0.0001) samples. CCL18/PARC mRNA expression was much higher in RA synovial membrane than OA samples (p = 0.0001). All RA cartilage and synovial tissue samples exhibited medium to strong staining for CCL18/PARC. Serum levels of CCL18/PARC were higher in RA patients (156.21 +/- 125.73 ng/ml, n = 71) than in OA patients (64.54 +/- 40.90 ng/ml, n = 12) and controls (28.04 +/- 10.96 ng/ml, n = 20). Levels of CCL18/PARC in RA SF (275.20 +/- 228.16 ng/ml, n = 15) were higher than in OA (33.13 +/- 14.84 ng/ml, n = 6; p = 0.0198). CCL18/PARC levels correlated significantly with rheumatoid factor levels (r = 0.431, p = 0.0040), but not with matrix metalloproteinase-3, erythrocyte sedimentation rate, and C-reactive protein. CONCLUSION: CCL18/PARC was highly expressed in RA articular cartilage and synovial tissue compared with OA samples. Our data indicated that CCL18/PARC levels are not related to the conditions of generalized inflammation, but are related to the pathogenesis of RA.     

Receptor expression in synovial fluid neutrophils from patients with rheumatoid arthritis.

OBJECTIVES--The aim of this study was to determine if neutrophils isolated from the blood and synovial fluid of patients with rheumatoid arthritis had patterns of receptor expression resembling those of blood neutrophils from controls which had been activated and primed in vitro. METHODS--Fluorescence activated cell sorting was used to measure receptor expression in paired blood and synovial fluid neutrophils from patients and in control neutrophils exposed to phorbol myristate acetate and granulocyte-macrophage colony stimulating factor. RESULTS--There was no significant difference in the patterns of receptor expression in blood neutrophils from patients and healthy controls, but neutrophils in the synovial fluid had been primed and activated within the joint. About 50% of rheumatoid synovial fluid neutrophil samples expressed Fc gamma RI, a high affinity receptor for monomeric IgG, which is only expressed in neutrophils exposed to cytokines. CONCLUSIONS--Synovial fluid neutrophils are activated and primed within the inflamed joint and hence their ability to respond to activating factors such as immune complexes will be modulated. As the expression of Fc gamma RI requires active biosynthesis, this work indicates that selective gene activation occurs when neutrophils are recruited into rheumatoid joints.     

CD69 expression on neutrophils from patients with rheumatoid arthritis

OBJECTIVE: Since the early activation antigen CD69 has been implicated in the pathogenesis of some inflammatory diseases, we evaluated the expression of the molecule on peripheral blood (PB) and synovial fluid (SF) neutrophils obtained from RA patients and its possible correlation with PB and SF cytokine concentration. METHODS: CD69 membrane expression (and CD11b as control marker) was assessed by indirect immunofluorescence and flow cytometry analysis on purified PB and SF neutrophils. Cytokine levels (GM-CSF, IFN-gamma, TNF-alpha) in plasma and SF supernatants were measured by ELISA. RESULTS: CD69 was absent on control neutrophils, while it was expressed on PB neutrophils from RA patients although no detectable GM-CSF, IFN-gamma or TNF-alpha was observed in their plasma. CD69 expression was still more evident on SF neutrophils from RA patients; 59% had detectable levels of INF-gamma in their SF while GM-CSF and TNF-alpha were detectable in SF from 95% and 33% of RA patients, respectively. However, no correlation was observed between cytokine concentrations and CD69 expression on SF neutrophils. SF but not PB neutrophils from RA patients expressed increased amounts of CD11b when compared to control PB neutrophils without any correlation with CD69 membrane expression. CONCLUSION: The activation antigen CD69 is significantly expressed on PB and SF neutrophils from RA patients. However, the mechanism(s) of induction and its possible role in the pathogenesis of RA remain to be defined.     

Intracellular oxidative activation in synovial fluid neutrophils from patients with rheumatoid arthritis but not from other arthritis patients

OBJECTIVE: To compare total and intracellular oxidative activation of blood and synovial fluid (SF) neutrophils from patients with rheumatoid arthritis (RA) and other arthritides with blood donor neutrophils. METHODS: Peripheral blood and SF samples were obtained from 26 gonarthritis patients (13 RA, 13 non-RA) attending the rheumatology unit for therapeutic joint aspiration. Isolated neutrophils were stimulated by a formylated tripeptide (fMLF) or by microbeads coated with collagen-I. Formation of superoxide-anion-derived reactive oxygen species (ROS) was studied by luminol-enhanced chemiluminescence. Paired samples of blood and SF neutrophils from patients with active arthritis were compared with blood neutrophils from patients in remission and from 47 healthy blood donors. RESULTS: SF neutrophils from patients with RA, but not from non-RA patients, showed high baseline intracellular ROS production. Blood neutrophils from arthritis patients in remission existed in a primed state as revealed by more rapid oxidative response after collagen-bead challenge and a more pronounced response after fMLF stimulation compared to healthy blood donors. Blood neutrophils from RA patients with ongoing gonarthritis, however, did not differ from healthy blood donors concerning oxidative activation, whereas blood neutrophils from non-RA patients with gonarthritis showed a significantly lower peak ROS production. CONCLUSIONS: A novel finding with pathogenetic implications in our study is that SF neutrophils from patients with RA, but not other arthritides, are activated and produce ROS intracellularly. This implies that synovial neutrophils in RA are engaged in the processing of endocytosed material.     

Oxidative response of polymorphonuclear leucocytes to synovial fluids from patients with rheumatoid arthritis.

Only a minority (7/35, 20%) of synovial fluids from patients with rheumatoid arthritis (RA) and none from patients with other arthritides stimulated the oxidative response of polymorphonuclear leucocytes (PMNs). Superoxide anion generation was measured by superoxide dismutase inhibitable reduction of cytochrome c. The same synovial fluids stimulated superoxide release by PMNs regardless of their source, though they elicited a greater response from RA synovial fluid PMNs than from either RA blood PMNs or blood PMNs from normal subjects. The remaining synovial fluids failed to stimulate any of the PMNs, though some (2/10) stimulated PMNs pretreated with cytochalasin B. The stimulatory activity was removed from RA synovial fluids by protein A-Sepharose and eluted with the void volume on gel chromatography. It is considered that immunoglobulin aggregates in some RA synovial fluids may stimulate the oxidative response of PMNs in the joint space but that most do not because these fluids contain either a specific inhibitor or immunoglobulin aggregates of an inappropriate type, or both.     

Elastase from polymorphonuclear leukocyte in articular cartilage and synovial fluids of patients with rheumatoid arthritis

Summary Objective was to study the significance and the mechanism of action of elastase from polymorphonuclear leukocyte (PMN elastase) in patients with rheumatoid arthritis (RA). The experiments conducted consisted of two phases. Firstly, articular cartilage and synovia from 8 patients with RA undergoing total knee replacement were obtained, and the gelatinolytic enzyme activity was extracted with 2M guanidine hydrochloride. The gelatinolytic activity of each tissue was measured to confirm that the activity was due to PMN elastase by using an antihuman leukocyte elastase antibody. Secondly, the levels of PMN elastase-1 proteinase inhibitor complex (EIC) in the blood and synovial fluid of 170 patients with RA were measured by immunoassay. The results were as follows: 1. Gelatinolitic activity was shown to be mainly due to PMN elastase, and found to be highest in cartilage and synovia in RA joints. 2. The EIC levels in plasma of RA patients were significantly higher than those in gout and osteoarthritis (OA), and the EIC levels increased according to the stage of articular cartilage destruction. Moreover, the EIC levels in synovial fluid of RA patients were higher compared to those of OA patients. The activity of PMN elastase was elevated in destructive joints of RA. With the progression of articular cartilage destruction, EIC levels in plasma of RA patients increased as well. We suggest that PMN elastase may play a significant role in RA disease.     

Synovial vascular patterns and angiogenic factors expression in synovial tissue and serum of patients with rheumatoid arthritis

OBJECTIVE: To determine whether subgroups of rheumatoid arthritis (RA) patients classified according to their synovial vascular pattern have a different expression of angiogenic mediators or exhibit distinct clinical or biological characteristics. METHODS: Arthroscopies were performed in 27 patients with RA and synovial samples were obtained. Vascular morphology was classified in three patterns: straight (S), tortuous (T) and mixed (M). Immunostaining was performed with anti-vascular endothelial growth factor (anti-VEGF), anti-vascular endothelial growth factor receptor (VEGFR)-1, anti-VEGFR-2, anti-IL-8 and anti-TGF-beta, and measured by digital image analysis. Serum levels of VEGF, TGF-beta and IL-8, and clinical, radiographic and serological data were also analysed. RESULTS: Eleven (41%) patients had the S pattern, nine (33%) the M pattern and seven (26%) the T pattern. The S and M groups had a higher prevalence of rheumatoid factor positivity and erosive disease, and higher levels of markers of systemic inflammation compared with the T group. Synovial expression of VEGF was higher in the S and T groups compared with the M group, whereas TGF-beta was higher in the T compared with the S and M groups. Distinct synovial distribution of VEGF and TGF-beta between groups was also observed. CONCLUSIONS: This preliminary study suggests that RA patients with the S and M patterns share different clinical, biological and serological characteristics compared with those with the T pattern, which may constitute a group with less severe disease. Differences in the intensity and distribution of synovial expression of VEGF and TGF-beta observed between groups could have pathophysiological relevance. However, larger, prospective multicentre studies would be need to determine the clinical relevance of vascular patterns in RA.     

A tissue kallikrein in the synovial fluid of patients with rheumatoid arthritis.

Tissue kallikrein is an enzyme that forms the vasoactive peptide kallidin from an endogenous substrate L-kininogen. Tissue kallikrein has been identified in joint fluids and in inflammatory infiltrates within synovial membranes. It is suggested that tissue kallikrein and kinins have an important role in synovitis and joint damage. Immunoreactive tissue kallikrein and amidase activity were both measured in the synovial fluid of 24 patients with rheumatoid arthritis (RA) and 12 with osteoarthritis (OA). Active enzyme concentrations were higher in RA than in OA and correlated well with the lysosomal enzymes beta-glucuronidase and lactate dehydrogenase. Both total immunoreactive tissue kallikrein and the proenzyme values were similar in RA and OA. Tissue kallikrein was localised by immunocytochemistry to the polymorphonuclear leucocytes present in the synovial fluid and membranes of patients with RA.     

Lymphocytes eluted from synovial tissue of juvenile rheumatoid arthritis patients

Synovial tissues from 11 patients with juvenile rheumatoid arthritis were investigated. The elution of lymphocytes was performed according to a procedure previously described for synovial tissue of adult rheumatoid arthritis patients (1). The T lymphocytes were predominant (mean: 71%) in all cell suspensions studied, whereas the average proportion of B lymphocytes was 4%. In addition, Fc-receptor-bearing lymphocytes were demonstrable (mean: 8%). Transformation of the lymphocytes was induced by the unspecific mitogens phytohemagglutinin, pokeweed mitogen, and concanavallin A, whereas antigens such as PPD and candida albicans antigen were usually ineffective.     

白细胞介素-23在类风湿关节炎滑膜中的表达及意义

目的白细胞介素（IL）-23由IL-23p19和IL-12p40亚单位组成，它在一些自身免疫疾病发生过程中起着重要的作用。研究分析类风湿关节炎（RA）患者关节滑膜组织中IL-23p19蛋白及其mRNA的表达，旨在探讨其在RA发病中的意义。方法应用反转录-聚合酶链反应（RT—PCR）和免疫组织化学方法检测RA患者关节滑膜组织中IL-23p19基因和蛋白的表达。并与骨关节炎（OA）患者和健康人作对照研究。结果IL-23p19mRNA和蛋白在RA患者关节滑膜组织中表达明显增高．而在OA患者中低表达，正常对照组中无表达。结论IL-23p19在RA关节滑膜组织中高表达．提示IL-23可能直接参与了RA的发病过程。     

Lytic Epstein-Barr virus infection in the synovial tissue of patients with rheumatoid arthritis

OBJECTIVE: To evaluate the existence of Epstein-Barr virus (EBV) infection in the synovial tissue of patients with rheumatoid arthritis (RA). METHODS: Synovial tissues were obtained at synovectomy or arthroplasty from 32 patients with RA and 30 control patients with osteoarthritis (OA). EBV DNA was detected by Southern blot hybridization and/or polymerase chain reaction (PCR) amplification. To localize the EBV-infected cells, tissue sections were studied by RNA in situ hybridization (ISH) for the EBV-encoded small RNA 1 (EBER-1), by DNA ISH for the Bam HI W region of EBV DNA, and by immunohistochemistry for EBV lytic proteins BZLF1 and gp350/220. RESULTS: EBV DNA was detected by PCR in 15 of the 32 samples from RA patients (47%), but in none of those from the 30 OA patients (P < 0.01). Of the 15 PCR-positive samples, 9 contained >1 EBV copy/1,000 cells (referred to as EBV 2+), and 6 contained 1 copy/1,000-5,000 cells (EBV 1+). Among the 9 EBV 2+ samples, 3 were also positive for EBV DNA by Southern blot hybridization, 5 were positive for EBER-1 by RNA ISH, and 3 were positive for EBV DNA by DNA ISH. Immunohistochemical analysis showed positive signals in all samples for BZLF1 and in 7 samples for gp350/ 220. In each examination, the positive signals were detected not only in lymphocytes, but also in synovial lining cells. CONCLUSION: EBV was frequently detected in the synovial tissue of RA patients. The infected cells were both lymphocytes and synovial cells, and expressed EBV proteins associated with virus replication. These findings suggest that EBV may play a role in the pathogenesis of RA.     

类风湿关节炎患者血清滑液和滑膜组织白细胞介素-18的水平及意义

目的 研究类风湿关节炎（RA）患者血清、滑液中白细胞介素－18（IL－18）蛋白及滑膜组织IL－18mRNA表达水平，探讨其在RA致病中的作用。方法 应用双抗夹心酶免疫吸附（ELISA）法和细胞生物法分别测定RA患者血清、滑液中IL－28蛋白水平和生物活性，同时还检测NO、前列腺素E2的含量；有用半定量RT－PCR法检测膜组织IL－18m RNAG表达水平。以骨关节炎（OA）病人及因外伤截肢的正常人作对照。结果 RA患者血清、滑液中IL－18蛋白水平和生物活性均显著高于对照组，滑液中量及活化性比血清高；RA滑膜组织IL－18mRNA表达水平也明显高于对照组。结论 过度表达的IL－18参与了RA的致病过程,；选择性地抑制IL－18生物活性，将是RA治疗的新途径。     

Osteoprotegerin expression in synovial tissue from patients with rheumatoid arthritis,spondyloarthropathies and osteoarthritis and normal controls

OBJECTIVES: To demonstrate the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB ligand (RANKL) in synovial tissue from rheumatoid arthritis (RA) patients, establish the cell lineage expressing OPG and compare the expression of OPG in RA, spondyloarthropathies, osteoarthritis and normal synovial tissue. METHODS: Synovial biopsy specimens were obtained at arthroscopy from 16 RA and 12 spondyloarthropathy patients with active synovitis of a knee joint, six RA patients with no evidence of active synovitis, 10 patients with osteoarthritis and 18 normal subjects. Immunohistological analysis was performed using monoclonal antibodies (mAb) to detect OPG and RANKL expression. In addition, dual immunohistochemical evaluation was performed with lineage-specific monoclonal antibodies (macrophages, fibroblasts and endothelial cells) and OPG to determine the cell lineages expressing OPG. The sections were evaluated by computer-assisted image analysis and semiquantitative analysis. RESULTS: Two patterns of OPG expression were seen, one exclusively in endothelial cells and one expressed predominantly in macrophages in the synovial lining layer. Both patterns of OPG staining could be blocked with excess recombinant OPG. Endothelial and synovial lining expression of OPG was seen in all synovial tissues except those from patients with active RA. In contrast, RANKL expression was seen predominantly in synovial tissue from patients with active disease, mainly in sublining regions, particularly within areas of lymphocyte infiltration. CONCLUSIONS: OPG expression on macrophage type synovial lining cells as well as endothelial cells is deficient in RA patients with active synovitis, in contrast to that seen in spondyloarthropathy patients with active synovitis. This deficiency in OPG expression in the inflamed joint of RA patients may be important in the development of radiologically defined joint erosions.