Beta-thromboglobulin in inflammatory synovial fluid

Activated platelets release substances which potentially can contribute to joint lesions in inflammatory arthritides. To elucidate a possible participation of platelets in inflammatory joint reactions, the concentrations of the platelet proteinβ-thromboglobulin (β-TG) were measured in 90 inflammatory synovial fluids. Seven percent of the patients with rheumatoid arthritis and none of the patients with other inflammatory joint diseases (e.g., Reiter's disease, reactive or crystal arthritides) hadβ-TG concentrations in synovial fluid exceeding the upper normal range of plasma β-TG. The absent or very modest signs of local platelet activation were contrasted by the pronounced neutrophilic and monocytic activation, as assessed by the measurements of some granule proteins: lactoferrin, myeloperoxidase, lysozyme, and ferritin. No correlation was found between these inflammatory cell markers andβ-TG. A positive correlation (p < 0.001) was noted betweenβ-TG andβ-microglobulin, which appeared in particularly high amounts in rheumatoid arthritis. This correlation may reflect a disturbed permeability of synovial membrane for LMW proteins or a related activation of platelets and lymphocytes. The present results do not give any evidence of platelet activation playing a major role in proliferative or destructive processes in arthritis.     

Stimulation of osteoclast formation by inflammatory synovial fluid

Peri-articular bone resorption is a feature of arthritis due to crystal deposition and rheumatoid disease. Under these conditions, the synovial fluid contains numerous inflammatory cells that produce cytokines and growth factors which promote osteoclast formation. The aim of this study was to determine whether inflammatory synovial fluid stimulates the formation of osteoclasts. Synovial fluid from rheumatoid arthritis (RA), pyrophosphate arthropathy (PPA) and osteoarthritis (OA) patients was added to cultures (n=8) of human peripheral blood mononuclear cells (PBMCs) in the presence and absence of macrophage colony-stimulating factor (M-CSF) and the receptor activator of NF-κB ligand (RANKL). Osteoclast formation was assessed by the formation of cells positive for tartrate-resistant acid phosphatase (TRAP) and vitronectin receptor (VNR) and the extent of lacunar resorption. The addition of 10% OA, RA and PPA synovial fluid to PBMC cultures resulted in the formation of numerous multinucleated or mononuclear TRAP⁺ and VNR⁺ cells which were capable of lacunar resorption. In contrast to PBMC cultures incubated with OA synovial fluid, there was marked stimulation of osteoclast formation and resorption in cultures containing inflammatory RA and PPA synovial fluid which contained high levels of tumour necrosis factor alpha, a factor which is known to stimulate RANKL-induced osteoclast formation.     

Pronounced production of polyclonal immunoglobulin G1 in the synovial fluid of goats with caprine arthritis-encephalitis virus infection

Infection of goats with caprine arthritis-encephalitis virus, a lentivirus, resulted in arthritis characterized by the production of intrasynovial immunoglobulin G1 concentrations that were 2 to 5.3 times the serum concentrations in the inoculated carpi at 6 months postinoculation. The intrasynovial immunoglobulin was polyclonal, and its presence was accompanied by increased albumin leakage into the joints. Synovial fluid immunoglobulin levels fluctuated temporally but remained elevated compared with medium-inoculated controls for 38 months after infection. Elevated immunoglobulin G1 concentrations correlated with focal sublumenal plasmacytic infiltrates in the synovia of inoculated carpi at 5 months postinoculation. Inflammation in the uninoculated joints of infected goats was also accompanied by increased intrasynovial immunoglobulin G1 levels. Antibody to systemically administered antigens was a greater proportion of the immunoglobulin population in sera than in synovial fluids of infected goats, suggesting that antibody production to local antigens was responsible for increased intrasynovial immunoglobulin G1 levels.     

Clonal heterogeneity of synovial fluid T lymphocytes in inflammatory synovitis.

Several studies have examined patients with rheumatoid arthritis for the presence of oligoclonal populations of synovial T lymphocytes. The results of these studies have been conflicting. In this study one patient with rheumatoid arthritis and two with other forms of inflammatory synovitis were examined by Southern blot analysis of T cell clones generated from synovial fluid by primary limiting dilution. Evidence of oligoclonality was documented only in a patient with psoriatic arthritis. The distinguishing characteristics of this patient, in addition to the diagnosis, included the fact that only one joint was involved, the synovitis in the affected joint was of recent onset, and the synovial fluid lymphocytes from which the T cells were cloned responded strongly to soluble antigens. Because of the association with the strong response to soluble antigens, synovial fluid T lymphocytes from another patient with rheumatoid arthritis were cloned in response to a crude mycobacterial antigenic mixture. Three of the seven clones examined were identical by Southern blot analysis. These observations suggest that the presence of oligoclonality is limited in patients with inflammatory arthritis. The relationship of a specific antigen-driven response within the joint to the detection of oligoclonal T cells within that joint remains to be determined.     

Altered function of synovial fluid granulocytes in patients with acute inflammatory arthritis

In rheumatoid arthritis (RA) a chronic inflammatory state exists in which the synovial fluid is periodically filled with large numbers of polymorphonuclear leukocytes (PMNs). Oxygen radicals produced by these cells have been implicated as mediators of tissue damage and may be directly involved in the pathogenesis of RA. We examined the production of oxygen radicals by synovial fluid PMNs (SFPMNs) and peripheral blood PMNs (PB-PMNs) by measuring chemiluminescence (CL) as well as Superoxide anion (O ₂ ^– ) release. Increased spontaneous CL in the presence of luminol and increased CL in response to phorbol myristate acetate (PMA) was observed in SF-PMNs when compared to PB-PMNs. When zymosan was used as the stimulus in the absence of luminol, a slightly lower CL response was observed in SF-PMNs as compared to PB-PMNs. No significant differences were observed in the generation of O ₂ ^– generation with any stimulus. Preincubation of normal PBPMNs in 10% synovial fluid enhanced the luminol-dependent spontaneous and PMA-stimulated CL as well as zymosan-stimulated CL. When O ₂ ^– release from normal PB-PMNs pretreated with 10% synovial fluid was compared to untreated controls, enhancement of spontaneous O ₂ ^– release was observed. PMA- and zymosan-stimulated responses did not differ significantly from controls. Increased spontaneous and PMA-stimulated release of myeloperoxidase (MPO) was also observed in normal PB-PMNs pretreated with synovial fluid. These findings may explain the increased luminol-dependent CL since this type of CL requires the presence of MPO. Our findings suggest that the enhanced chemiluminescence observed in normal PMNs treated with synovial fluids may be related to increases in spontaneous O ₂ ^– generation and myeloperoxidase release. Increased MPO release may account for enhanced CL observed in SF-PMNs.     

Application of fluoroimmunoassay to cerebrospinal fluid immunoglobulin G and albumin.

Special solid-phase fluoroimmunoasssay protocols were used to measure the amount of immunoglobulin G (IgG) and albumin in 1,511 samples of cerebrospinal fluid. The fluoroimmunoassay is an inhibition test conducted on the surface of a plastic probe, whose fluorescence is inversely related to the concentration of spinal fluid IgG or albumin. A microcomputer interfaced with the fluorometer calculates the sample IgG or albumin from a calibration curve based on standard cerebrospinal fluid values. The test and interpretation take less than 90 min. Correlation coefficients for over 100 cerebrospinal fluid samples tested by both fluoroimmunoassay and radial immunodiffusion were: IgG, 0.90 (slope, 1.04); albumin, 0.95 (slope, 0.99). The within-run precision (coefficient of variation) was: IgG, 4.4%; albumin, 6.3%. Run-to-run precision on a midrange sample was: IgG, 7.7%, albumin, 11.7%. These findings establish the simplicity, speed, and precision of the modified fluoroimmunoassay system for specific cerebrospinal fluid proteins.     

膝骨关节炎时关节滑液中炎症相关物质的表达

背景：膝骨关节炎的主要改变是关节软骨面的退行性病变和继发性的骨质增生,病变的机制还不明确,但现已有实验证实膝骨关节炎的发病与炎症相关物质有密切的关系。 目的：分析炎症相关物质在膝骨关节炎发病机制中的作用。 方法：按美国风湿病学分会制定的诊断标准选择膝骨关节炎患者60例,来自因外伤截肢或半月板损伤性手术治疗的患者(排除膝关节内损伤)60例作为对照组,抽取两组患者膝关节液,采用酶联免疫吸附试验方法检测白细胞介素1β、白细胞介素6、白细胞介素8、白细胞介素10、肿瘤坏死因子α、碱性成纤维细胞生长因子、骨桥蛋白水平,采用一氧化氮检测试剂盒检测一氧化氮水平,按TBA荧光法测定过氧化脂质浓度。 结果与结论：膝骨关节炎患者表达高水平白细胞介素1β、白细胞介素6、白细胞介素8、白细胞介素10、肿瘤坏死因子α、碱性成纤维细胞生长因子、骨桥蛋白、一氧化氮和过氧化脂质水平均明显高于对照组;这些细胞因子及一氧化氮、过氧化脂质与膝骨关节炎的病变呈正相关。结果提示这些炎症相关物质确实参与了人膝骨关节炎的发病进程。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

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.     

Hypophysitis presented as inflammatory pseudotumor in immunoglobulin G4-related systemic disease

Immunoglobulin (Ig) G4-related systemic disease is a recently characterized entity. The best-known manifestation is pancreatitis. Other systemic involvements are also described. Three cases of this disease with hypophyseal involvement have been reported in the literature, all diagnosed clinically. We herein present the first case of IgG4-related hypophysitis diagnosed histopathologically. The patient is a 77-year-old Chinese man with a pituitary tumor. Histologic examination of the resected tumor showed hypophysitis with features of inflammatory pseudotumor. Clinical review showed history of pancreatitis and cholecystitis 4 years ago. The pancreatic biopsy and gall bladder specimens obtained previously had the same pathologic features of inflammatory pseudotumor. Immunohistochemistry highlighted abundant IgG4-positive plasma cells in all 3 specimens. Serum IgG4 level was also elevated. A diagnosis of IgG4-related systemic disease was confirmed. This is the first case of intracranial inflammatory pseudotumor shown to be associated with IgG4-related systemic disease.     

Identification of Mycoplasma fermentans in synovial fluid samples from arthritis patients with inflammatory disease

Since 1970 Mycoplasma fermentans has been suspected of being associated with rheumatoid arthritis. However, this association has been difficult to prove, and this has been our goal. The distribution of M. fermentans was studied in the synovial fluid of patients suffering from different arthritides. Samples of synovial fluid were taken from patients with well-defined disease and a clear diagnosis. After removal of the inflammatory cells and hyaluran, they were treated with proteinase K and tested by a single or fully nested PCR with primers directed against part of the two 16S rRNA genes of M. fermentans. The product was sequenced automatically, by using an ALF Express automatic sequencer, to confirm the mycoplasma species and to identify the strain since the two genes were usually found to be polymorphic. This was also true of the type strain, strain PG18. M. fermentans was detected in 23 of 26 (88%) rheumatoid arthritis patients, and four different strains were found. It was also found in 7 of 8 (88%) of the nonrheumatoid inflammatory arthritis patient group, which consisted of one patient with reactive arthritis, one patient with pauciarticular juvenile chronic arthritis, two patients with gout, two patients with ankylosing spondylitis, and two patients with psoriatic arthritis, only one of whom was infected with M. fermentans. It was not detected in any of the 10 osteoarthritis patients. M. fermentans was therefore found to be a variable and very common organism in arthritic patients with inflammatory joint exudates and may well prove to be important in the etiology of the diseases.     

Influence of host factors on immunoglobulin G concentration in oral fluid specimens.

The influence of host factors (tobacco use, dentition, bleeding gums, oral rinsing, nasal medications, and time since the last meal) on immunoglobulin G (IgG) concentration in oral fluids (OF) was determined by univariate and multivariate analysis. Significant differences in IgG concentration were found to be associated with human immunodeficiency virus (HIV) status (HIV antibody positive, +16.60 microg/ml, P = 0.0001), sex (female, +1.23 microg/ml, P = 0.004), dentition (+2.83 microg/ml, edentulous versus dentulous, P = 0.0001), bleeding gums (+6.35 microg/ml, P = 0.0001), and time since the last meal (+3.55 microg/ml, >6 h, P = 0.0001). These factors could impact diagnostic methods that rely on the immunoglobulin concentration in OF specimens.     

The enigma of oligoclonal immunoglobulin G in cerebrospinal fluid from multiple sclerosis patients

The cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) contains immunoglobulin G (IgG) of restricted heterogeneity (oligoclonal IgG). Philip Paterson and Caroline Whitacre here review the core evidence that IgG in MS patients and normal subjects is synthezised intracerebrally and that most of it does- not have demonstrable antigenic specificity. They advance the view that the enigmatic oligoclonal IgG may be a product of B cells which are non-specifically activated by mitogenic stimuli originating within injured CNS tissue as a consequence of the MS process.     

Direct modification of plasma low-density lipoproteins in interstitial inflammatory fluid of the rabbit

Utilizing the polyvinyl sponge-implant model in the rabbit, we have previously demonstrated modification in low-density lipoproteins (LDL) in the extravascular space in association with a cellular inflammatory response. In an attempt to isolate the source of these modifications, plasma LDL was labeled with¹²⁵I, and introduced directly into the extravascular space at the time of sponge implantation. [¹²⁵I] plasma LDL recovered from interstitial inflammatory fluid (IF) at 24 h after implantation demonstrated increased electrophoretic mobility as well as heterogeneity in particle size and hydrated density. These results are in agreement with our previous observations and indicate that modification in IF-LDL probably occurs after it has entered the extravascular space across the vascular wall.     

Oxidative modification of leukocyte adhesion

In this issue of Immunity, Marko Salmi and colleagues describe mice lacking AOC3, an endothelial cell monoaminooxidase that is involved in modulating leukocyte rolling, adhesion, and migration (Stolen et al., 2005). Their data demonstrate the importance of oxidative modification of (unknown) adhesion molecules in regulating inflammation and lymphocyte homing.     

Cytologic examination of synovial fluid

Cytologic study of synovial fluid has been relatively neglected both by cytologists and rheumatologists. Currently identified implications of cytologic findings include definitive diagnoses of a variety of joint diseases such as those due to malignancies, infections, or pathogenic crystals. Diagnoses can also be strongly suggested, for example, by visualization of lupus erythematosus cells formed in vivo. Immunocytochemistry is being explored for diagnostic and pathogenetic implications. We propose that complementary techniques used in our cytology and rheumatology laboratories may provide new insights into the clinical significance of cellular changes in joint fluids.     

The effects of chemical modification on the antigenicity of human and rabbit immunoglobulin G.

In order to characterize the precise structure within human and rabbit IgG molecules against which 'general' rheumatoid factors are directed, an immunochemical comparison has been made of the effects of the selective substitution of specific amino acid side-chains on various types of antigenicity exhibited by human and rabbit IgG. The epsilon-amino groups of lysine residues have been substituted by citraconylation and carbamylation; whilst tyrosine residues have been substituted by nitration with tetranitromethane. In this manner, evidence has been obtained which indicates that the autoantigenic determinants of human IgG are structurally distinct from species-specific ones and from certain Fc-located allotypic markers (Gm(a) and Gm(x)). It is also concluded that lysine residues are probably not involved in the site of IgG reactivity with 'general' rheumatoid factors, in contrast to tyrosine residues which appear to be implicated in the activity of human but not rabbit IgG.     

Spontaneous generation of functional osteoclasts from synovial fluid mononuclear cells as a model of inflammatory osteoclastogenesis

In osteoimmunology, osteoclastogenesis is understood in the context of the immune system. Today, the in vitro model for osteoclastogenesis necessitates the addition of recombinant human receptor activator of nuclear factor kappa‐B ligand (RANKL) and macrophage colony‐stimulating factor (M‐CSF). The peripheral joints of patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) are characterized by an immune‐mediated inflammation that can lead to bone destruction. Here, we evaluate spontaneous in vitro osteoclastogenesis in cultures of synovial fluid mononuclear cells (SFMCs) activated only in vivo. SFMCs were isolated and cultured for 21 days at 0.5–1.0 × 10⁶ cells/mL in culture medium. SFMCs and healthy control peripheral blood monocytes were cultured with RANKL and M‐CSF as controls. Tartrate‐resistant acid phosphatase (TRAP) positive multinucleated cells were found in the SFMC cultures after 21 days. These cells expressed the osteoclast genes calcitonin receptor, cathepsin K, and integrin β3, formed lacunae on dentin plates and secreted matrix metalloproteinase 9 (MMP9) and TRAP. Adding RANKL and M‐CSF potentiated this secretion. In conclusion, we show that SFMCs from inflamed peripheral joints can spontaneously develop into functionally active osteoclasts ex vivo. Our study provides a simple in vitro model for studying inflammatory osteoclastogenesis.     

Augmented plasma and tissue kallikrein like activity in synovial fluid of patients with inflammatory articular diseases

We studied some of the components of the kininogen-kallikrein-kinin system, simultaneously, in plasma and synovial effusions of patients with inflammatory articular diseases. Plasma and tissue kallikrein like activity and kininogen levels were evaluated. Active plasma and tissue kallikreins in plasma and synovial fluid were detected by their amidase activity upon specific chromogenic substrates. Kininogen levels were determined by a bioassay. Both specific amidase activity of plasma and tissue kallikreins were augmented in synovial effusions in relation to their own plasma activity. Kininogen levels in synovial fluid tended to be diminished in relation to plasma, however statistical significance was not reached. The consumption of kininogen is probably related to kinin production. This finding together with increased activities of plasma and tissue kallikreins reinforce the involvement of kinins in pathogenesis of inflammatory articular diseases.accepted by W. B. van den Berg