The levels of soluble granzyme A and B are elevated in plasma and synovial fluid of patients with rheumatoid arthritis (RA).

Cytotoxic cells possess specialized granules which contain perforin and a group of serine proteinases termed granzymes. Granzyme-positive cells have been identified in synovial fluid and tissue of patients with RA, where they may play an important role as mediators of granule-mediated apoptosis, extracellular proteolysis, and cytokine induction. The aim here was to define further the involvement of cytotoxic cells in RA. Plasma and synovial fluid samples from the knee joint were obtained from 31 RA patients. The disease controls included 20 osteoarthritis (OA) patients and 10 reactive arthritis (ReA) patients. A recently developed capture ELISA was used to detect soluble granzymes A and B in all patients. Compared with OA and ReA disease controls, markedly increased levels of soluble granzymes A and B were detected in both plasma and synovial fluid of RA patients (P < 0.00001). When values for soluble granzymes A and B in plasma and synovial fluid were used simultaneously as independent variables, logistic regression analysis indicated that a diagnosis of RA could be predicted correctly in 84% of the RA patients and a diagnosis of non-RA in 90% of the controls. The markedly elevated levels of soluble granzymes A and B in plasma and synovial fluid of RA patients strongly suggest that cytotoxic cells are active participants in the pathogenesis of RA. Moreover, the results suggest that measurement of granzymes may assist the laboratory evaluation of patients with arthritis. Larger studies in patients with early disease may clarify the role of this test system in differential diagnosis.     

Elevated angiogenin levels in synovial fluid from patients with inflammatory arthritis and secretion of angiogenin by cultured synovial fibroblasts

Angiogenesis is a key process in the pathogenesis of inflammatory arthritis. Angiogenin is one of the most potent inducers of neovascularization in experimental models in vivo. To look for evidence that angiogenin is involved in inflammatory joint disease, we examined plasma and synovial fluid (SF) samples from rheumatology patients and synovial fibroblast cell culture supernatants. Angiogenin levels were determined by radioimmunoassay and ELISA. Plasma angiogenin concentrations ranged from 96 to 478 ng/ml, with no significant difference between patients and normal controls. In SF, angiogenin concentrations were significantly higher in patients with acute or chronic synovitis (rheumatoid arthritis (RA): median, 104 ng/ml; range 13-748, n = 14; crystal-induced arthritis (CIA): median, 149 ng/ml; range, 37-616, n = 14, and other chronic inflammatory arthritis: median, 42 ng/ml; range, 15-205; n = 9) than in the 18 patients with osteoarthritis (OA) (median, 20 ng/ml; range 8-116) (P < 0.0001, anova). Angiogenin levels in SF from RA patients in remission with secondary OA were similar to those achieved in primary OA, and decreased in parallel with the resolution of acute gout. Angiogenin protein was released by cultured synovial fibroblasts from OA and RA patients, and reached 1.18 ng/106 cells/day. These data suggest that angiogenin may mediate local inflammation in arthritis via effects on angiogenesis and leucocyte regulation.     

Site‐specific absence of microfibrillar‐associated protein 4 (MFAP4) from the internal elastic membrane of arterioles in the rheumatoid arthritis synovial membrane: an immunohistochemical study in patients with advanced rheumatoid arthritis versus osteoarthritis

Microfibrillar‐associated protein 4 (MFAP4) is a non‐structural matrix protein with cell regulatory activities and a potential as seromarker for fibrosis. We aimed to study the occurrence of MFAP4 in the synovial membrane from patients with rheumatoid arthritis (RA) vs osteoarthritis (OA). Formaldehyde‐fixed synovial tissue sections, from patients with RA (N = 6) and OA (N = 6) undergoing total hip arthroplasty, were deparaffinized and immunostained with monoclonal antibodies against MFAP4. Elastin was detected using ElastiKit. MFAP4 in serum (sMFAP4) and synovial fluid was measured by an immunoassay. MFAP4 was present in synovial biopsies from both RA and OA patients, particularly prominent in deep arterioles where it colocalized with elastin. Notably however, MFAP4 was absent from the internal elastic lamina in RA arterioles irrespective of disease duration and synovitis activity, while present although with irregular staining patterns in OA specimens. sMFAP4 was increased in RA and OA serum vs healthy controls: median (interquartile range) 29.8 (25.3–39.1) and 25.5 U/L (18.1–43.3) vs 17.7 U/L (13.7–21.2), p = 0.006 and p = 0.02, respectively The concentration of synovial fluid was lower than in serum in both RA and OA. These findings may suggest that MFAP4 is involved in adaptive vessel wall remodeling associated with chronic joint disease.     

Increased Expression of Activation-Induced Cytidine Deaminase is Associated with Anti-CCP and Rheumatoid Factor in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is associated with higher levels of autoantibodies and IL-17. Here, we investigated if ectopic lymphoid follicles and peripheral blood mononuclear cells (PBMCs) from RA patients exhibit increased activation-induced cytidine deaminase (AID), and if increased AID is correlated with serum levels of autoantibodies and IL-17. The results of immunohistochemical staining showed that organized AID⁺ germinal centres were observed in six of the 12 RA synovial samples, and AID⁺ cells were found almost exclusively in the B-cell areas of these follicles. Aggregated but not organized lymphoid follicles were found in only one OA synovial sample without AID⁺ cells. Significantly higher levels of AID mRNA ( Aicda ) detected by RT-PCR were found in the PBMCs from RA patients than PBMCs from normal controls ( P  < 0.01). In the PBMCs from RA patients, AID was expressed predominately by the CD10⁺IgM⁺CD20⁺ B-cell population and the percentage of these cells that expressed AID was significantly higher than in normal controls ( P  < 0.01). AID expression in the PBMCs correlated significantly and positively with the serum levels of rheumatoid factor (RF) ( P  ≤ 0.0001) and anti-cyclic citrullinated peptide (CCP) ( P  = 0.0005). Serum levels of IFN-γ ( P  = 0.0005) and IL-17 ( P  = 0.007), but not IL-4, also exhibited positive correlation with the expression of AID. These results suggest that the higher levels of AID expression in B cells of RA patients correlate with, and may be associated with the higher levels of T helper cell cytokines IFN-γ and IL-17, leading to the development of anti-CCP and RF.     

Terminal complement complexes and C1/C1 inhibitor complexes in rheumatoid arthritis and other arthritic conditions.

Terminal complement complex (TCC) and C1r-C1s-C1 inhibitor complex (C1/C1 INH) concentrations were measured in plasma and synovial fluid from patients with arthritis and related to other measures of disease activity. Both TCC and C1/C1 INH concentrations were significantly increased in patients with rheumatoid arthritis (RA) compared with patients with osteoarthritis (plasma and synovial fluid, P less than 0.05) and normal subjects (plasma only, P less than 0.001). In the patients with RA, there was no correlation between plasma or synovial fluid TCC concentrations and IgM rheumatoid factor, immune complex or C1/C1 INH levels. However, in 10 patients with seronegative RA, C1/C1 INH and immune complex levels correlated significantly in synovial fluid (r = 0.69, P less than 0.05) although not in plasma (r = 0.52). Plasma and synovial fluid TCC and C1/C1 INH concentrations did not differ in rheumatoid patients with severe compared with mild joint disease (categorized by the Ritchie score). These results confirm a role for complement activation in RA but suggest that several mechanisms are involved in its pathogenesis.     

The role of IL-12 in inflammatory activity of patients with rheumatoid arthritis (RA)

The aim of this study was to investigate the role of IL-12 in patients with RA. IL-12 (p70) and its associated cytokines were measured in sera and synovial fluid (SF) using an enzyme-linked immunosorbent method. Seven American College of Rheumatology (ACR) core set measures as well as IL-12 levels were sequentially monitored at the commencement and 4 months after treatment with a low-dose steroid and disease-modifying anti-rheumatic drugs (DMARDs). In sera, 64 (42.2%) of 152 RA patients had detectable concentrations of IL-12 (p70), whereas one (1.4%) of 69 osteoarthritis (OA) patients and five (10%) of 50 healthy controls had detectable IL-12 (P < 0.001). The median level of circulating IL-12 was also higher in RA patients (P < 0.001). In SF, the number of patients with detectable IL-12 and the median IL-12 levels were significantly higher in RA patients (n = 53) than in OA patients (n = 22). In paired samples (n = 53) of sera and SF from RA patients, IL-12 levels were higher in the SF than in sera (P < 0.001). Patients with detectable IL-12 (n = 51) in sera had higher tender joint scores (P = 0.003), swollen joint scores (P < 0.001) and C-reactive protein (CRP; P = 0.036), than those without (n = 55). Four months after treatment with DMARDs, the improved group showed a larger IL-12 decrease than the non-improved group (P = 0.017). The levels of IL-12 correlated positively with those of IL-2, interferon-gamma, IL-6, and tumour necrosis factor-alpha, but were correlated inversely with those of IL-10. Our results demonstrate that IL-12 levels reflect RA disease activity and that IL-12 is involved in the production of proinflammatory cytokines. An IL-12 blockade could be useful for the treatment of RA.     

Elevated expression of TAM receptor tyrosine kinase in synovial fluid and synovial tissue of rheumatoid arthritis

To investigate the expression and roles of TAM (Tyro3/Axl/Mer) receptor tyrosine kinases (TK) in synovial fluid and synovial tissue of patients with rheumatoid arthritis (RA). The expression of TAM TKs in the synovial fluid and synovial tissues of RA and osteoarthritis (OA) patients was measured by ELISA and immunohistochemistry. The relationships between soluble TAM TKs (sTAM TKs) levels and the clinical features, laboratory parameters and disease activity were analyzed in RA. The concentrations of sTAM TK in the synovial fluids of RA patients were increased in comparison to those of OA patients. Compared with OA patients, the expression of membrane Tyro3 TK (mTyro3 TK) and mMer TK in RA patient synovial tissue were significantly increased, which may partly explain the possible mechanism of elevated levels of sTAM TK in RA patient synovial fluid. sAxl TK levels were decreased in RA patients under sulfasalazine treatment and elevated in patients under Iguratimod treatment. Furthermore, sTyro3 TK levels were positively correlated with erythrocyte sedimentation rate (ESR) and negatively correlated with white blood cells (WBCs), red blood cells (RBCs), and hemoglobin (HB) in RA patients. The levels of sMer TK were positively associated with disease duration and rheumatoid factor (RF) and negatively correlated with HB, complement 3 (C3), and C4. Taken together, TAM TKs might be involved in RA synovial tissue inflammation.     

The influence of synovial fluids from patients with rheumatic diseases on chick embryo fibroblasts

Primary chick-embryo fibroblasts (PCEF) were used as target cells to measure the influence of synovial fluids of patients suffering from osteoarthritis (OA; n = 5), rheumatoid arthritis (RA; n = 12) and psoriatic arthritis (PA; n = 2). The following metabolic cell products were measured: DNA, RNA, glycosaminoglycans (GAG), sulfated glycosaminoglycans, protein and collagen, with the same joint effusions being used in each test. Since it is not a single substance that provokes a stimulating or inhibiting effect in the joint, the crude synovial fluids were applied in these preliminary experiments. It was found that each type of synovial fluid showed an influence on the biological processes in the PCEF. The DNA, RNA and GAG syntheses were strongly influenced by the joint effusions, in contrast to the protein, collagen and sulfated glycosaminoglycan syntheses which were less affected. Generally, the nucleic acid synthesis differed significantly between the OA, RA and PA synovial fluids. The addition of heparin to the synovial fluids caused an additive inhibiting effect on the DNA synthesis but did not influence the other biochemical parameters. The synovial fluids of RA patients, and to a much greater extent those of PA patients, inhibited the thymidine incorporation whereas OA synovial fluids had a less pronounced effect. This result indicates a disease-dependent composition of the synovial fluids. RNA synthesis was diminished in all three groups, but again this effect was strongest in the case of the PA synovial fluids. GAG synthesis was markedly stimulated by the PA synovial fluids and somewhat, though to a lesser extent, by the OA and RA synovial fluids. The sulfated glycosaminoglycan synthesis in the PCEF, as revealed by 35S incorporation into the GAG, was less influenced and on the whole stimulated by the OA and RA synovial fluids. The same trend could be observed with regard to the collagen synthesis. The intracellular protein synthesis was less influenced by the OA (91.9%) and more strongly suppressed by the RA (78.7%) and the PA (76.7%) synovial fluids. PCEF therefore appear to be a convenient and sensitive target cell system to study alterations of biochemical processes caused by crude synovial fluids and also of different origin by individual factors isolated from synovial fluids.     

A study of opioid peptides in synovial fluid and synovial tissue in patients with rheumatoid arthritis]

Authors have often experienced that psychological stress influences rheumatoid arthritis (RA). In addition, recent reports show a modulatory role for neuropeptide such as substance P in arthritis. These findings prompted us to study endogenous opioid peptides in RA, which are found mainly in the brain and have an effect on the central nervous system. We examined methionine-enkephalin (Met-enk), leucine-enkephalin (Leu-enk) and beta-endorphin (beta-end) in opioid peptides. We measured these peptides in plasma and synovial fluid samples obtained from 28 knees of 24 RA patients and the quantity in the synovial tissue of 13 knees. We also measured plasma and synovial fluid samples from patients with osteoarthritis of the knee and plasma samples from healthy candidates. Leu-enk and beta-end levels in synovial fluid were significantly higher than plasma levels only in RA. Larger quantity of Leu-end and beta-end were contained apparently in the synovial tissue than Met-enk. The synovial tissue with proliferative change tends to contain larger quantity of opioid peptides. These results indicate that the synovial tissue produces or secretes Leu-enk and beta-end and that opioid peptides are related to the degree of inflammation in RA.     

强直性脊柱炎和类风湿关节炎患者内皮素-1、降钙素基因相关肽水平的临床观察

目的：探讨内皮素-1（ET-1）、降钙素基因相关肽（CGRP）在强直性脊柱炎（AS）和类风湿关节炎（RA）病理生理过程中的作用。方法：用放射免疫法检测AS和RA患者血浆及关节液中ET-1、CGRP含量,并与健康志愿（HC）组进行比较。结果：AS、RA组血浆ET-1水平均明显高于HC组（P<0.01）;AS组和RA组血浆CGRP水平均与HC组无显著差异（P>0.05）;关节滑液中CGRP水平明显高于血浆（P<0.01）,ET-1水平明显低于血浆（P<0.01）。结论：ET-1、CGRP参与了AS、RA病理生理过程,但在AS、RA疾病过程中作用机制不同。     

Clock gene expression in different synovial cells of patients with rheumatoid arthritis and osteoarthritis

Patients with rheumatoid arthritis (RA) show modulated circadian rhythms of inflammatory cytokines and cortisol, which may be associated with a modified expression of clock genes. The expression of major clock genes was previously studied in synovial tissues and fibroblasts of patients with RA and osteoarthritis (OA). We therefore especially aimed to examine the localization of clock genes at the cellular level in synovial tissue. Furthermore we were interested in studying the expression of the D site of albumin promoter (albumin D-box) binding protein (DBP) at the immunohistochemical level in human samples. Methods used include the in situ expression of the clock genes Brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1 (Bmal 1), Circadian Locomotor Output Cycles Kaput (Clock), Period 1 and 2 (Per 1 and Per 2), and DBP was examined by immunohistochemistry in synovial tissues of patients with RA or OA. Additionally, expression profiles of different clock genes were determined over 24 h by real time PCR in synovial fibroblasts (SFs) after a 2 h serum shock or TNF-α. Results show that all clock genes investigated were found to be expressed both in RA and OA synovial tissues. Double staining against cell specific markers revealed that clock proteins were especially seen in macrophages, SFs and B-lymphocytes. Cell counting showed that clock proteins were found in approximately 5–20% of cells. Additionally, preliminary cell culture experiments showed that TNF-α treatment resulted in differential 24 h expression profiles between RA and OA samples and also compared to the results obtained from the serum shock experiments. From our study we conclude that the major clock genes, including DBP, are expressed in samples from RA and OA patients, especially in macrophages and synovial fibroblasts, but also in B-lymphocytes. Preliminary experiments suggest that TNF-α seems to be able to modify clock gene expression in synovial fibroblasts.     

Soluble Forms of P-Selectin and Intercellular Adhesion Molecule-3 in Synovial Fluids

A number of adhesion molecules have been identified in synovial tissues of patients with rheumatoid arthritis (RA). Some of them are upregulated and may play an important role in the inflammatory processes of the diseased joint. In addition to synovial tissue cell surface expression, synovial fluids contain soluble forms of many adhesion molecules, such as intercellular adhesion molecule-1, E-selectin (sE-selectin), and L-selectin. In this study, we investigated the expression of soluble P-selectin (sP-selectin) and intercellular adhesion molecule-3 (sICAM-3) in synovial fluids from patients with RA, osteoarthritis (OA), and other forms of arthritis. sP-selectin and sICAM-3 levels in RA synovial fluids were significantly increased compared to those in OA. The levels of sP-selectin in synovial fluids correlated with sICAM-3 and sE-selectin in synovial fluids. The levels of sICAM-3 in synovial fluids correlated with synovial fluid leukocyte counts and erythrocyte sedimentation rate.In vitro,synovial fluid mononuclear cells produced sICAM-3 spontaneously. Elevated levels of sP-selectin and sICAM-3 in RA synovial fluids compared to OA may indicate inflammatory interactions between endothelial cells, leukocytes, and other synovial cells in the diseased joint.     

Role of opioid peptide in rheumatoid arthritis--detection of beta-endorphin in synovial tissue]

The presence of beta-endorphin (beta-end) was immunohistologically identified in synovial tissue samples biopsied from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). The amount of beta-end in culture supernatants of synovial tissue explants was also determined by RIA. beta-end was strongly detected in mainly superficial synovial cells, vascular endothelial cells and a few synovial interstitial cells in RA patients, but not in OA patients. In RA patients the beta-end concentration was significantly higher in the supernatants of tissue explants (26.4 +/- 8.3 pg/ml) than in the plasma of the same patients (15.3 +/- 2.5 pg/ml) (p < 0.01). Using isolated synovial cells, the beta-end concentration in the culture supernatants of non-adherent cells (19.4 pg/ml) was higher than that of adherent cells (4.0 pg/ml). It is suggested that beta-end is produced by non-adherent cells such as lymphocytes and neutrophils in addition to synovial lining cells and endothelial cells and may play some role in the pathology of RA synovial inflammation.     

类风湿关节炎患者关节液中HSP72水平变化与疾病活动性及炎症因子水平相关性分析

目的观察类风湿关节炎(RA)患者关节液中热休克蛋白72(HSP72)的水平变化,并对其与疾病活动性相关指标和细胞因子之间的相关性进行分析。方法采用酶联免疫吸附法(ELISA)检测RA患者和骨关节炎(OA)患者关节液中HSP72、TNF-α、IL-6、IL-10的表达水平。结果活动期RA患者关节液中HSP72水平明显高于非活动期RA患者和OA对照组(P<0.01)。活动期RA患者关节液中TNF-α、IL-6的水平均高于非活动期RA患者和OA对照者(P<0.01),关节液中IL-10在各组之间无显著差异。RA患者关节液中HSP72的水平与血沉(ESR)、C反应蛋白(CRP)、风湿因子(RF)呈正相关;RA患者关节液中HSP72的水平与关节液中TNF-α、IL-6水平呈正相关。结论关节液中HSP72可能与RA的炎症相关,与RA病情活动有关。