The igg,igm, and iga isotypes of anti-topoisomerase i and anticentromere autoantibodies

We studied the expression of IgG, IgM, and IgA autoantibodies in the anti-topoisomerase I and anticentromere immune responses by enzyme-linked immunosorbent assay, immunoblotting, and immunofluorescence. While IgG autoantibodies were most common, IgA autoantibodies were also frequently found, but IgM autoantibodies were rare. This is the first report of IgA autoantibodies in scleroderma.     

Allotypic dependency of the specificity and avidity of human monoclonal igm rheumatoid factors derived from rheumatoid synovial cells

Objective. To better understand the genetic derivation and pathogenicity of rheumatoid factor (RF) molecules in rheumatoid arthritis (RA), we have focused our studies on rheumatoid synovial cells (RSC). Methods. Five monoclonal human IgM rheumatoid factor (mRF)—secreting hybridomas were produced from the RSC of an RA patient. Fine subclass specificities and avidities of these RSC mRFs were compared with several paraprotein monoclonal IgM RFs using direct binding (reactivity) and competitive inhibition (specificity and avidity) enzyme-linked immunosorbent assays. Results. The following observations were made: 1) RSC mRF had greater avidity for IgG than did paraprotein mRF; 2) 4 of the 5 RSC RF were highly avid for IgG3; and, 3) the avidity of RSC RF binding for IgG3 was highest for IgG molecules expressing the G3m(5) allotype. Conclusion. We conclude that RSC RF have different specificities and avidities than do paraprotein RF. This may suggest an antigen-driven process in RA synovium, with the production of higher-avidity IgG3m(5)-specific RSC RF, which could have special pathogenetic importance.     

Serologic and molecular characterization of a human monoclonal rheumatoid factor derived from rheumatoid synovial cells

Molecular characterization of rheumatoid factors (RF) in rheumatoid arthritis (RA) has been hampered because of their polyclonality. To overcome this problem, we generated monoclonal RF-secreting hybridomas from rheumatoid synovial cells. Among the RF-secreting hybridomas, HAF10 secreted an IgM-RF that was monospecific for human IgG. It bound well to IgG1 and IgG2, but not to IgG3 and IgG4. Sequence analysis of its heavy and light chains showed that it contained a VH1 heavy chain and a V lambda light chain that did not belong to any known lambda light chain subgroup, and therefore, probably represented a new lambda subgroup. These results indicated that both the heavy and light chains of a monoclonal IgM-RF from rheumatoid synovial cells were quite different from the reported variable region sequences of several monoclonal RF derived mainly from patients with mixed cryoglobulinemia. Further studies of additional monoclonal RF from RA patients are warranted to define precisely their genetic basis and to further our understanding of the immunopathology of RA.     

Quantitation of human synovial mast cells in rheumatoid arthritis and other rheumatic diseases

We examined sections of synovial membranes from 14 patients with rheumatoid arthritis (RA), 7 with other rheumatic diseases, and 10 with no apparent joint disease. Patients with RA and other rheumatic diseases had significantly more synovial mast cells/vessel than patients with no joint disease (0.49 and 0.20, respectively, versus 0.03). They also had significantly more total mast cells/10 fields than patients with no joint disease (9.9 and 5.0, respectively, versus 0.4). Within the rheumatoid group, patients with active disease had more total mast cells/10 fields than patients clinically considered to have end-stage disease (P < 0.05). Synovial basophils were not identified in any patient. Synovial vascularity was similar for all groups (2.3 vessels/field). The role of the synovial mast cell in RA and other rheumatic diseases remains to be determined.     

Resistin in rheumatoid arthritis synovial tissue, synovial fluid and serum

BACKGROUND: Resistin is a newly identified adipocytokine which has demonstrated links between obesity and insulin resistance in rodents. In humans, proinflammatory properties of resistin are superior to its insulin resistance-inducing effects. OBJECTIVES: To assess resistin expression in synovial tissues, serum and synovial fluid from patients with rheumatoid arthritis, osteoarthritis and spondylarthropathies (SpA), and to study its relationship with inflammatory status and rheumatoid arthritis disease activity. METHODS: Resistin expression and localisation in synovial tissue was determined by immunohistochemistry and confocal microscopy. Serum and synovial fluid resistin, leptin, interleukin (IL)1beta, IL6, IL8, tumour necrosis factor alpha, and monocyte chemoattractant protein-1 levels were measured. The clinical activity of patients with rheumatoid arthritis was assessed according to the 28 joint count Disease Activity Score (DAS28). RESULTS: Resistin was detected in the synovium in both rheumatoid arthritis and osteoarthritis. Staining in the sublining layer was more intensive in patients with rheumatoid arthritis compared with those with osteoarthritis. In rheumatoid arthritis, macrophages (CD68), B lymphocytes (CD20) and plasma cells (CD138) but not T lymphocytes (CD3) showed colocalisation with resistin. Synovial fluid resistin was higher in patients with rheumatoid arthritis than in those with SpA or osteoarthritis (both p<0.001). In patients with rheumatoid arthritis and SpA, serum resistin levels were higher than those with osteoarthritis (p<0.01). Increased serum resistin in patients with rheumatoid arthritis correlated with both CRP (r=0.53, p<0.02), and DAS28 (r=0.44, p<0.05), but not with selected (adipo) cytokines. CONCLUSION: The upregulated resistin at local sites of inflammation and the link between serum resistin, inflammation and disease activity suggest a role for resistin in the pathogenesis of rheumatoid arthritis.     

Properties of rheumatoid and normal synovial tissue in vitro and cells derived from them

Summary Using organ and cell culture techniques for tissues and cells derived from human sources, we have investigated cellular interactions involving synovial tissue. Normal synovium in culture produced less prostaglandin E (PGE) and collagenase than cultures of rheumatoid synovial fragments. When synovial tissue was dissociated by enzymatic digestion, monolayers of adherent cells were established in primary culture. The adherent cells rapidly lost the ability to synthesize large amounts of PGE and collagenase and rheumatoid synovial cells became indistinguishable from normal synovial cells. Supernatants from cultured human mononuclear blood cells contained activities (Mononuclear cell factor(s)=MCF) which stimulated PGE and collagenase production by either normal or rheumatoid synovial cells. Conditioned medium from cultures of either normal or rheumatoid synovial fragments (Synovial factor(s)=SF) also stimulated production of PGE and collagenase by these human cells. Both MCF and SF also stimulated the production of PGE by cells isolated from human trabecular bone. Since both normal and rheumatoid synovial cells respond similarly to these factors, there appears to be little specificity with regard to whether the target cells are derived from normal or pathological sources. Furthermore, since both normal and rheumatoid synovium are able to produce similar amounts of stimulatory activity, inflammatory cells are not solely responsible for these phenomena. Normal synovium must therefore contain cells which can be recruited to participate in these potential cellular interactions. Destruction of joint structures may be mediated by factors of the type studied here, which may be produced when there is failure of the mechanisms that prevent them from being synthesised or released.     

Mechanism of stimulation of prostaglandin synthesis by a factor from rheumatoid synovial tissue.

Rheumatoid synovial cell monolayers, with [1-14C]arachidonic acid ([1-14C]AA) incorporated into cell lipids, are stimulated by a factor (RSF) produced by explant cultures of rheumatoid synovial tissue to produce up to 50-fold increases in [1-14C]prostaglandin E2 and [1-14C]prostaglandin I2. In contrast, levels of free [1-14C]AA released from RSF-stimulated cells are generally lower than [1-14C]AA levels in cultures of untreated cells. These observations are inconsistent with a mechanism of prostaglandin stimulation consisting of an increase in phospholipase activity, because this mechanism would increase free AA levels as well as prostaglandins. A mechanism is proposed in which free AA is maintained at low steady-state levels by reacylation of free AA into phospholipids at a rate more rapid than its reaction with cyclooxygenase to form prostaglandins. In this mechanism, stimulation of the rate of the cyclooxygenase step by RSF accounts for increased prostaglandin synthesis as well as the decreased release of AA. On the basis of data previously reported by others, it is suggested that this mechanism may also be applicable to the stimulation of prostaglandin synthesis by several other agents. Preliminary characterization of the RSF indicates that it is a protein, and molecular seive chromatography indicates that its molecular weight is about 18,000. The production of RSF by rheumatoid synovial tissue is suppressed to undetectable levels by 1 microM dexamethasone.     

The effects of igm rheumatoid factor on eam and eag rosette formation with fc receptor-bearing lymphoid cells

IgM rheumatoid factors (IgM-RF) and IgM from normal donors (IgM-C) were tested for their effects on rosette formation of Fc receptor (FcR)-bearing lymphoid cells with IgM- or IgG-coated bovine red blood cells (EA_M or _G). All cell populations tested bearing F_cR for IgG (F_cR_G) showed reduced numbers of EA_G rosettes formed in the presence of IgM-RF; IgM-C had no effect on EA_G rosette formation with F_cR_G-bearing cells. T cells or L cells bearing F_cR_M showed reduced numbers of EA_M rosettes in the presence of any IgM preparation. In addition, IgM-RF facilitated EA_G-ro-sette formation with T_M cells. These studies confirm that native IgM can bind to F_cR_M, blocking EA_M rosettes, and that IgM-RF can modulate the binding of an IgG-containing immune complex to F_cR-bearing cells.     

Immunohistochemical analysis of proliferating and antigen-presenting cells in rheumatoid synovial tissue

We analysed the proliferative activity of synovial lining cells (SLCs), the distribution of proliferating B and T lymphocytes and the relationship of proliferating B and T lymphocytes to the pattern of antigen-presenting cells (APCs) within the rheumatoid synovial tissue (n=21). The immunohistochemical detection of the proliferation-associated antigen Ki 67 revealed low proliferative activity of SCL with and without expression of the Kim 8 (CD 68) antigen. Ki 67-positive B lymphocytes could be observed within secondary follicles (2/21), in small follicular dendritic reticulum cell (FDC)-containing follicle-like aggregates (7/21) and near the enlarged synovial intima (6/21). Ki 67-positive T lymphocytes could be detected in T-lymphocyte aaggregates (8/21), in the vicinity of blood vessels (18/21) and within the enlarged synovial intima (15/21). Semiquantitative analysis showed a strong correlation between the numbers of Ki 67-positive B lymphocytes and FDCs and between the numbers of Ki 67-positive T lymphocytes and interdigitating dendritic reticulum cells (IDC). There were significant differences in the number of Ki 67-positive B and T lymphocytes, IDCs and FDCs between the two groups of rheumatoid arthritis (RA) patients with different local clinical activity. These findings demonstrate a low proliferation of SLCs with and without expression of the monocyte-specific antigen Kim 8 and imply that B and T lymphocyte proliferation occurs in the presence of FDCs and IDCs. These results indicate that the RA synovial tissue is a site for antigen-dependent proliferation and maturation of B and T lymphocytes. The atypical pattern of FDC distribution within the rheumatoid synovial tissue dysmorphic follicle may be regarded as morphological substrate for a dysmaturation compartment of B lymphocytes leading to pathogenetic autoimmune phenomena in RA patients.This paper is dedicated to Prof. Dr. H. G. Schwarzacher on the occasion of his retirement as head of the Institute of Embryology and Histology University of Vienna, Austria     

IgA rheumatoid factor synthesis by dissociated synovial cells. Characterization and relationship to IgM rheumatoid factor synthesis

We examined patterns of IgA rheumatoid factor (RF) and IgM-RF synthesis by dissociated synovial cells obtained from 27 patients with seropositive rheumatoid arthritis. Synthesis of IgA-RF was observed in 19 of 34 synovial cell preparations from these patients and constituted a mean of 16% of the total IgA produced. IgA-RF expression correlated only weakly with IgM-RF production (r = 0.385) and could be dissociated from production of IgA-RF (and IgM-RF) exhibited by simultaneously obtained peripheral blood plasma cells. While wide variations were observed in the ratio of IgA-RF:IgM-RF produced by synovial B cells in the patient sample studied, remarkable consistency in the relationship of IgA-RF to IgM-RF synthesis was observed over time in different joints of the same patient. IgA-RF synthesized by dissociated synovial cells was predominantly of the IgA1 subclass and existed in both monomeric and polymeric forms. Our results are compatible with the view that local production of IgA-RF and IgM-RF are regulated independently of each other.     

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.     

Quantitation of metalloproteinase gene expression in rheumatoid and psoriatic arthritis synovial tissue distal and proximal to the cartilage-pannus junction

OBJECTIVE: The distinct and different patterns of radiological damage in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) may be a product of the relative balance of proteolytic enzyme and inhibitor gene expression in synovial tissue. This study compared metalloproteinase gene expression in synovium located proximal to the cartilage-pannus junction (CPJ) and distal to the CPJ (non-CPJ) in patients with PsA and RA. METHODS: Synovial biopsies were obtained from CPJ and non-CPJ sites under direct vision at arthroscopy of an inflamed knee in patients with PsA (n = 12) and RA (n = 12) who were not under disease modifying antirheumatic drug treatment. A competitive, quantitative RT-PCR technique was established for synovial RNA using a polycompetitor construct containing mRNA-specific primer sites for collagenase (MMP-1), stromelysin (MMP-3), tissue inhibitor of metalloproteinase-1 (TIMP-1), and GAPDH. cDNA products were separated and quantified by ethidium bromide stained gel electrophoresis and mRNA values were normalized relative to GAPDH expression. RESULTS: MMP-1, MMP-3, and TIMP-1 mRNA were upregulated in RA and PsA synovium with a prodestructive (MMP-1 + MMP-3)/TIMP-1 balance in both diseases. Similar levels of MMP mRNA expression were observed in PsA and RA despite the presence of less radiological erosion in the PsA group. No difference was observed in the degree of upregulation of MMP-1, MMP-3, or TIMP-1 mRNA in paired biopsies from CPJ and non-CPJ sites in either PsA (n = 8) or RA (n = 10). The ratio of TIMP-1 expression in CPJ compared to non-CPJ biopsies was higher in patients with nonerosive disease (10.1 +/- 27.8) than in erosive patients (0.75 +/- 0.27; p = 0.07). CONCLUSION: PsA and RA have similar levels of MMP-1, MMP-3, and TIMP-1 mRNA expression in synovium. There is no evidence of increased metalloproteinase mRNA expression at the CPJ in RA or PsA. The different patterns of radiological progression seen in RA and PsA were not explained by differences in synovial mRNA expression of MMP-1, MMP-3, or TIMP-1.     

类风湿关节炎患者滑膜、滑液和血浆中PAI的检测及其临床意义

目的 检测Ⅰ型和Ⅱ型纤深酶原激活物抑制剂（ＰＡＩ－１和ＰＡＩ－２）在类风湿关节炎（ＲＡ）患者滑膜组织中的定位和表达,同时测定ＲＡ患者滑液和血浆中ＰＡＩ－１的含量和活性,并分析其临床意义。方法 运用免疫组织化学方法检测了２４例ＲＡ、１８例骨关节炎（ＯＡ）和６例正常滑膜组织中ＰＡＩ－１和ＰＡＩ－２的定位及其表达;采用ＥＬＩＳＡ双抗体夹心法测定４６例ＲＡ和８例ＯＡ患者血浆、１４例ＲＡ滑液和１２例正常对照     

High prevalence of iga rheumatoid factor in severe polyarticular-onset juvenile rheumatoid arthritis,but not in systemic-onset or pauciarticular-onset disease

The presence of IgA rheumatoid factor (IgA-RF) has been correlated with severe joint disease in adult rheumatoid arthritis (RA), but IgA-RF has not been reported in juvenile rheumatoid arthritis (JRA). In the present study, IgA-RF was assayed by an enzyme-linked immunosorbent assay and was found in the sera of 14 of 24 children (58%) with active polyarticular JRA. The presence of IgA-RF correlated with the degree of functional disability. In contrast, IgA-RF was not found in the sera of systemic-onset disease patients, regardless of the degree of dysfunction. IgA-RF was detected in only 1 patient with pauciarticular disease, despite the fact that several patients in this group had severe disease. The presence of IgA-RF in polyarticular JRA did not correlate with serum IgA levels, but did correlate with the presence and the level of serum IgM-RF. Thus, the presence of IgA-RF appears to be specific for polyarticular JRA, and shows a correlation with severe disease in this group.     

Heat shock protein 70 membrane expression on fibroblast-like synovial cells derived from synovial tissue of patients with rheumatoid and juvenile idiopathic arthritis

OBJECTIVE: To screen fibroblast-like synovial cells derived from synovial tissue of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) patients for the membrane expression of the heat shock protein Hsp70. METHODS: We performed flow cytometric (fluorescence-activated cell sorting, or FACS) analysis on fibroblast-like synovial cells of 15 RA patients and three JIA patients to investigate Hsp70 membrane expression. Skin fibroblasts derived from the operation wound (n = 4) and peripheral blood mononuclear cells (PBMC) of seven RA and three JIA patients were also tested. Peripheral blood lymphocytes (PBL) and skin fibroblasts of 10 healthy individuals were used as negative controls. RESULTS: A significantly higher percentage of Hsp70 membrane expression was found on fibroblast-like synovial cells derived from arthritis-affected joints in RA patients (mean 47.7%) when compared with autologous skin fibroblasts (mean 9.5%, p < 0.001) and control skin fibroblasts (mean 5.6%, p < 0.001) or autologous PBL (mean CD45/Hsp70-positive 10.4%, p < 0.001) and control PBL (mean CD45/Hsp70-positive 7.7%, p < 0.001). A high percentage of Hsp70 membrane expression was also observed on fibroblast-like synovial cells derived from three patients with JIA (mean 35.2%) when compared with autologous PBL (mean CD45/Hsp70-positive 10.4%). Synovial cells derived from non-affected joints in a patient with RA who underwent synovectomy for trauma showed low expression of Hsp70 (10.9%). CONCLUSION: Fibroblast-like synovial cells derived from patients with severe course of RA and JIA are strongly positive for membrane-expressed Hsp70.     

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 pre dominant (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 mitrogens phytohemagglutinin, pokeweed mitogen, and concanavallin A, whereas antigens such as ppd and candida albicans antigen were usually ineffective.     

类风湿关节炎滑膜组织血管内皮生长因子转录和转录后的研究

目的 研究类风湿关节炎(RA)患者血清、滑液及滑膜组织中血管内皮生长因子(VEGF)的表达水平，探讨其在RA致病中的作用。方法 应用双抗夹心酶联免疫吸附测定（ELISA)法分别测定RA患者血清、滑液中VEGF蛋白水平；采用半定量反转录-聚合酶链反应(RT-PCR)法和Northern blot检测滑膜组织VEGF mRNA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VEGF蛋白水平显著高于对照组；RA滑膜组织VEGF mRNA表达水平也明显高于对照组。结论 RA患者滑膜组织VEGF的过度表达，引起血管增生，是引起RA发病的重要因素。