Increased helper inducer and decreased suppressor inducer phenotypes in the rheumatoid joint

Cells isolated from the joints of patients with rheumatoid arthritis (RA) exhibit functional immune abnormalities, such as diminished suppressor activity, depressed response to mitogens, and enhanced immunoglobulin production. We sought to characterize the T lymphocyte subsets in the synovial fluid (SF) and peripheral blood (PB) of RA patients in an attempt to clarify the mechanism(s) responsible for these functional immune abnormalities. We used dual-immunofluorescence staining techniques with several combinations of monoclonal antibodies, including anti-4B4 and anti-2H4, which define, respectively, the helper inducer and suppressor inducer subsets of CD4+ (Leu-3+ and T4+) cells. Mononuclear cells from normal PB (n = 9), RA PB (n = 6), and RA SF (n = 9) were analyzed, after staining, by flow cytometry. We observed a significant increase (P less than 0.0002) in the number of cells bearing the helper inducer phenotype (CD4+, 4B4+), and a significant decrease (P less than 0.0002) in the number of cells bearing the suppressor inducer phenotype (CD4+, 2H4+), in RA SF compared with the levels in PB from RA patients or normal control subjects. We also observed that the CD8+, 2H4+ subset was significantly decreased (P less than 0.0001) in SF compared with that in PB. There was no significant difference in the lymphocyte subset levels in PB from RA patients and from normal subjects. These observations may account, in part, for the reduced suppressor activity, the poor response to mitogens, and the autologous mixed lymphocyte reaction, as well as the enhanced production of Ig and rheumatoid factor, that are observed in the rheumatoid joint.     

Natural killer (NK) cells at inflammatory sites of patients with rheumatoid arthritis and IgM rheumatoid factor positive polyarticular juvenile rheumatoid arthritis

Summary NK cell activity and Leu 7⁺ cells were determined in mononuclear cells (MNC) from patients with rheumatoid arthritis (RA) and IgM rheumatoid factor positive polyarticular juvenile rheumatoid arthritis (JRA). NK cell activity was measured in a⁵¹Cr release assay and the Leu 7 positive cells were enumerated in indirect immunofluorescence. The mean NK cell activity ±SEM was reduced in MNC from peripheral blood (PB), synovial fluid (SF) and synovial membranes (SM's) of patients with RA, with the values of 19.5±1.4 (p<0.00003), 18.3±3.1 (p<0.009) and 2.9±0.5 (p<0.0003) respectively, compared with 26.1±1.4 in MNC from the PB of healthy controls. The mean percentages of Leu 7 positive cells in MNC from PB and SF on patients with RA were normal while the mean percentage of Leu 7⁺ cells in MNC eluted from SM's was significantly reduced as compared to that of MNC from PB of healthy controls (p<0.0006). In JRA similar results concerning NK activity and Leu 7 positive cells were found but the number of experiments was too low for statistical analysis. MNC from the SF, in contrast to that of BP and SM, had a significant cytoxicity against the Raji cell line which is a non-NK cell target.     

Phenotypes of T lymphocytes from peripheral blood and synovial fluid of patients with rheumatoid arthritis and juvenile rheumatoid arthritis. Evidence in favour of normal helper and suppressor functions of T lymphocytes from patients with juvenile rheumatoid arthritis

Lymphocytes from peripheral blood (PB) and synovial fluid (SF) from 21 patients with rheumatoid arthritis (RA) and 18 patients with juvenile rheumatoid arthritis (JRA) were studied with respect to T cell phenotypes using monoclonal antibodies in a rosette assay. The percentage of HLA-DR positive T cells was counted in PB and SF using indirect immunofluorescence. Suppressor cell activity of T cells from PB and SF was investigated by measuring the immunoglobulin production by pokeweed mitogen (PWM) stimulated B cells mixed with T cells at various ratios. The mean T4/T8 ratio was significantly lower in SF than in PB of both RA and JRA patients (p = 0.0062 and p less than 0.0001 respectively). The mean percentages of HLA-DR positive T cells were elevated in SF compared with PB in both patients groups (p less than 0.03 and p less than 0.04 in RA and JRA patients respectively). Mean suppressor cell activity and helper cell activity of T cells from SF and PB of JRA patients was normal. Thus there seems to be a dichotomy between the number of T8+ cells and suppressor cell function in mononuclear cells from SF of patients with JRA. This indicates that a considerable proportion of the T8+ cells in the SF do not have suppressor functions.     

Natural killer cells in the synovial fluid of rheumatoid arthritis patients exhibit a CD56bright,CD94bright,CD158negative phenotype

BACKGROUND: Natural killer (NK) cells play an important role in several animal models of autoimmunity by modulating T-cell responses, but it is unclear whether human NK cells have similar functions. METHODS: We characterized the phenotype of NK cells in synovial fluid (SF) and peripheral blood (PB) of patients with rheumatoid arthritis (RA) and in healthy control subjects using flow cytometry and quantitative PCR. RESULTS: The proportions of NK cells in PB and SF of RA patients were not significantly different from those in healthy PB. However, the SF NK cell phenotype was strikingly different, with increased CD94 and CD56 densities and greatly reduced proportions of cells expressing CD158a/b. These cells also had reduced mRNAs coding for CD158a/b and low perforin levels compared with RA PB and healthy PB NK cells. CONCLUSIONS: We identified a novel phenotype of SF NK cells that is of potential significance in RA. Experiments are now under way to determine the function of these SF NK cells and their potential role in RA.     

Differences in responses of normal and rheumatoid arthritis peripheral blood T cells to synovial fluid and peripheral blood dendritic cells in allogeneic mixed leukocyte reactions

We examined the response of normal T cells to dendritic cells isolated from the synovial fluid (SF) of patients with either rheumatoid arthritis (RA) or seronegative spondylarthropathies (rheumatoid variants) and to dendritic cells from normal and RA peripheral blood (PB) in the allogeneic mixed leukocyte reaction. Despite the differences in the response kinetics, the stimulatory capacity of SF dendritic cells was similar to that of PB dendritic cells in a 7-day mixed leukocyte reaction. We also tested the responsiveness of normal and RA PB T cells to various allogeneic dendritic cells and found that RA PB T cells responded poorly to both rheumatoid variant SF dendritic cells and normal PB dendritic cells. However, when dendritic cells from RA SF were used as stimulators, the response of RA PB T cells was significantly greater than that of normal PB T cells (P less than 0.02). This difference in response was explained in part by a proliferation of the CD8 T cell subset. There was also a shift of low-intensity CD4+, CDw29+ cells to high-intensity CD4+, CDw29+ cells seen in RA PB T cells but not in normal PB T cells, by fluorescence-activated cell sorter analysis.     

类风湿关节炎患者外周血及滑液NKp44+自然杀伤细胞的表达和临床意义探讨

目的 探讨类风湿关节炎(RA)患者外周血及滑液NKp44+自然杀伤细胞的临床意义.方法 采用流式细胞术检测20例活动期RA患者[疾病活动指数(DAS)28≥2.6]、15例缓解期RA患者(DAS28＜2.6)及20名健康对照者外周血NKp44+自然杀伤细胞比例及10例活动期RA患者滑液NKp44+自然杀伤细胞比例.多重非参数检验比较3组间NKp44+自然杀伤细胞比例差异.采用Spearmar相关分析NKp44+自然杀伤细胞与临床指标[DAS28评分、抗环瓜氨酸肽(CCP)抗体、类风湿因子(RF)]的相关性.结果 ①活动期、缓解期RA患者及健康对照者外周血NKp44+自然杀伤细胞比例分别为(1.480±4.750)%、(0.540±0.590)%、(0.000±0.000)%,活动期RA患者外周血NKp44+细胞比例明显高于缓解期和健康对照(x2=46.708,P=0.000).②10例活动期RA患者滑液NKp44+自然杀伤细胞比例为(15.6±11.7)%,明显高于其外周血NKp44+自然杀伤细胞比例(3.6±2.5)%(z=-3.780,P=0.000).③活动期RA患者外周血NKp44+自然杀伤细胞比例与DAS28评分、抗CCP抗体呈正相关(r=0.777,P=0.000;r=0.967,P=0.000),与RF无相关性(r=-0.343,P=0.138).滑液NKp44+自然杀伤细胞比例与DAS28评分、抗CCP抗体呈正相关(r=0.930,P=0.000;r=0.867,P=0.001),与RF无相关性(r=0.564,P=0.09).结论 NKp44+自然杀伤细胞在RA患者外周血及滑液中明显增高,且与DAS28评分、抗CCP抗体呈正相关,提示NKp44+自然杀伤细胞与疾病活动度和病情严重程度相关.

Abstract：

Objective To investigate the clinical significance of NKp44+NK cells in the peripheral blood and synovial fluid of rheumatoid arthritis (RA) patients.Methods The proportions of NKp44+NK cells in the PB of 20 active and 15 remission patients with RA and 20 healthy individuals were detected using flow cytometry.The proportions of NKp44+NK cells in the SF of 10 active patients were detected.Multiple nonparametric test was used to compared the difference of NKp44+NK cells proportions.Clinical data including DAS28,anti-CCP antibody and RF were collected.The relationship between NKp44+NK cells and clinical data was analyzed by Spearman correlation analysis.Results The proportions of NKp44+NK cells in PB of active and remission patients and healthy individuals were (1.480±4.750)%,(0.540±0.590)%,(0.000±0.000)%respectively.The proportion of NKp44+NK cells in PB of active patients was significantly higher than that of remission patients and healthy individuals (x2=46.708,P=0.000).The proportion of NKp44+NK cells in the SF of ten active RA patients was significantly higher than matched PB.There was positive correlation between NKp44+NK cells proportion in PB and SF of active patients and DAS 28 and anti-CCP antibody level.There was no correlation between NKp44+NK cells proportion in PB,SF and RF.Conclusion There is a marked increase in the proportion of NKp44+NK cells in PB and SF of RA patients.Moreover,NKp44+NK cells are positively correlated with DAS28 and anti-CCP antibody,suggesting that NKp44+NK cells may be correlated with disease activity and severity.     

A study of the effect of rheumatoid synovial fluid on proliferation and IL-2 production by total mononuclear cells and purified CD4+ cells of synovial fluid and peripheral blood

T cells from synovial fluid (SF) of rheumatoid arthritis (RA) patients have previously been shown to proliferate less after mitogenic stimulation and produce less interleukin 2 (IL-2) than normal T cells. To test whether SF is responsible for the reduced T-cell responses, we studied the effect of inflammatory SF on peripheral blood (PB) RA and normal mononuclear cells (MNC) and CD4+ T cells and on RA SF MNC and CD4+ cells in vitro. Most rheumatoid SF present in concentrations of 50% and 5% during in vitro stimulation increased mitogen-induced IL-2 production and proliferative response by normal PB and RA MNC and CD4+ cells. Other rheumatoid SF samples did not influence the T cell responses, while only a few samples had an inhibitory effect. The results indicate that SF contain both stimulatory and inhibitory factors and that the resultant effect on T cells may depend on the net effect of these. The results do not support the hypothesis that the apparently impaired function of SF T cells is due to contact with SF.     

Correlation between rheumatoid factor and IL-6 activity in synovial fluids from patients with rheumatoid arthritis

Synovial fluids (SF) and sera (S) from patients with rheumatoid arthritis (RA) were examined for IgM, IgM-rheumatoid factor (IgM-RF), albumin and interleukin-6 (IL-6) activity. The quotient of SF/S IgM-RF was elevated compared with that of SF/S albumin in 7 patients with seropositive RA, although the quotient of SF/S IgM was lower than that of SF/S albumin. SF IL-6 activity was much higher than serum IL-6 activity in all the 7 RA patients. In synovial fluids from 22 seropositive RA patients, SF IL-6 activity was significantly correlated with the SF IgM-RF, IgG-RF and IgA- less than RF, but not with SF IgM, IgG or IgA. Moreover, SF IgM-RF as well as SF IL-6 activity was significantly correlated with the Westergren erythrocyte sedimentation rate (ESR) or the Lansbury articular index. These results indicate that IL-6 and RF might be produced within the rheumatoid joints as a result of abnormal immune system activation, which is associated with the disease activity of RA. Three of the 4 seronegative RA patients, however, showed high SF IL-6 without detectable levels of SF IgM-RF, indicating that IL-6 alone is not sufficient for IgM-RF production.     

Spontaneous and pokeweed mitogen induced in vitro immunoglobulin and IgM rheumatoid factor production by peripheral blood and synovial fluid mononuclear cells in rheumatoid arthritis

Enzyme-linked immunosorbent assays (ELISA) were used to measure IgG, IgM and IgM rheumatoid factor (IgM RF) production in supernatants of pokeweed mitogen (PWM) stimulated peripheral blood mononuclear cells (PBMNC) of patients with rheumatoid arthritis (RA) and controls. Spontaneous and stimulated IgG and IgM production by RA and controls was comparable, but spontaneous production of IgM RF was only observed in RA and was related to their drug therapy. A significant difference was found between PWM induced IgM RF production in RA and controls and also between patients on "second-line" and on nonsteroidal anti-inflammatory drugs (NSAID). In addition, spontaneous IgM RF production by synovial fluid cells was significantly higher than the paired PBMNC.     

Rheumatoid arthritis serum or synovial fluid and interleukin 2 abnormally expand natural killer-like cells that are potent stimulators of IgM rheumatoid factor.

We show that rheumatoid arthritis (RA) serum or synovial fluid (SF) increases the growth capacity of normal, interleukin 2 (IL-2) driven cell preparations, compared to normal human serum (NHS). Proliferation in RA serum and SF cultures was primarily associated with expansion of natural killer (NK)-like cells (CD16+, CD57+), and in NHS cultures, with T cell (CD3+ CD4+ CD8+) growth. The capacity of RA serum to promote NK cell growth was related to patient global clinical activity and rheumatoid factor (RF) titers. The NK-like cells, but not the T-like cells, induced high levels of IgM RF synthesis in autologous B cells. Thus, alteration in NK cell growth may disrupt NK-B cell circuits in RA and contribute to B cell dysfunction (RF synthesis).     

Secretion of anti-citrulline-containing peptide antibody by B lymphocytes in rheumatoid arthritis

OBJECTIVE: To understand the regulation of anti-citrulline-containing peptide antibody (anti-CCP) production in rheumatoid arthritis (RA), production of anti-CCP by B cells derived from peripheral blood (PB), bone marrow (BM), and synovial fluid (SF) was examined. METHODS: Purified PB and SF B cells were isolated by negative selection and then cultured in the absence or presence of L-CD40 ligand cells and interleukin-10 or anti-CD3-activated T cells. Total IgM and IgM-anti-CCP were detected after 14 days of culture by enzyme-linked immunosorbent assay. Enzyme-linked immunospot assays were performed to analyze the frequency of cells that spontaneously produced IgM-anti-CCP in BM and SF B cells. RESULTS: IgM-anti-CCP autoantibodies were induced in PB B cells from healthy controls and RA patients following coculture with activated T cells or application of the CD40 activation system, whereas no production could be detected when PB B cells were cultured in the absence of a stimulus. SF and BM B cells from anti-CCP-seropositive RA patients, but not anti-CCP-seronegative patients, actively produced IgM-anti-CCP without stimulation. The frequency of spontaneous production of IgM-anti-CCP among the IgM-secreting cells ranged from 2.2% to 25%. CONCLUSION: These results indicate the presence of B cell precursors for anti-CCP autoantibodies that are able to produce antibodies upon stimulation in the PB B cell repertoire of healthy controls and patients with RA. In contrast, B cells that actively secreted anti-CCP were specifically present in the BM and SF compartment of anti-CCP-seropositive RA patients. The local presence of anti-CCP-secreting cells in the inflamed joints provides evidence for an antigen-driven maturation of CCP-specific B cells at the site of inflammation in RA.     

Anti-Human type II collagen CD19+ B cells are present in patients with rheumatoid arthritis and healthy individuals.

OBJECTIVE: To determine the frequency and repertoire of CD19+ B cells capable of producing antibodies reactive to type II collagen (CII) in synovial fluid (SF) and peripheral blood (PB) of patients with rheumatoid arthritis (RA) and PB of healthy control individuals. METHODS: CD19+ B cells were isolated and activated to secrete immunoglobulins (Ig) by CD4+ T cells. Frequencies of anti-CII B cells were determined by limiting dilution analysis. The isotype and cross-reactivity of the antibodies produced were determined by ELISA. RESULTS: SF and PB from 5 patients and PB from 4 healthy controls were analyzed. Anti-CII CD19+ B cells were identified in all samples tested. In the RA SF, the percentage of activated B cells reactive to human CII was significantly higher than in the PB of patients with RA (p < 0.05) or controls (p < 0.01). A majority of anti-human CII B cells from patients' SF secreted IgG isotype, whereas most anti-human CII B cells in PB of patients and controls secreted IgM. The anti-CII B cells, regardless of source, are usually reactive to both native and denatured human CII, to different types of human collagens, and to type II collagens from different species. CONCLUSION: Anti-CII CD19+ B cells responsive to activated helper T cells are present in both patients with RA and healthy individuals. However, these B cells, especially those secreting the IgG isotype, accumulate in the inflamed joints of RA patients.     

CD95-Mediated control of anti-citrullinated protein/peptides antibodies (ACPA)-producing plasma cells occurring in rheumatoid arthritis inflamed joints

OBJECTIVE: Serum anti-citrullinated protein/peptides antibodies (ACPA) are a valuable diagnostic parameter that might be involved in rheumatoid arthritis (RA) pathogenesis. CD95-dependent apoptosis is defective in RA synovium. The present study explores the occurrence of ACPA IgG, and the CD95-mediated control of ACPA IgG-secreting plasma cells (PC) in RA patients. METHODS: Mononuclear cells (MC) were purified from synovial fluid (SF) and peripheral blood (PB) of 15 RA patients. PC capable of secreting ACPA IgG were detected in MC cultures. ACPA IgG present in serum and SF, and PB and SF MC culture supernatant was measured by ELISA. CD95, CD27 and CD138 expression was examined on RA PC identified as CD19(low) CD38(high) cells by flow cytometry. CD95-ligation was obtained by treatment of cultured MC with the anti-CD95 Ab CH11. Apoptotic PC were identified as Annexin-V+. RESULTS: ACPA IgG level was found higher in patients' SF than in their serum. PC were detectable in SF and PB, and exhibited high CD95 and CD27 expression. In contrast, SF, but not PB, PC expressed elevated levels of CD138. SF, but not PB, PC actively secreted ACPA IgG in cultures, in a linear fashion for at least 14 days, and CD95-ligation markedly reduced this activity and provoked PC apoptosis. CONCLUSIONS: The results suggest that RA synovium is a prominent site for ACPA IgG formation and for the accumulation of ACPA IgG-secreting PC exhibiting prolonged survival, probably due to RA defective CD95-mediated control.     

Biased t cell receptor v gene usage in rheumatoid arthritis. oligoclonal expansion of t cells expressing vα2 genes in synovial fluid but not in peripheral blood

Objective. To analyze the T cell receptor (TCR) variable (V) region gene usage in the rheumatoid joint. Methods. Monoclonal antibodies (MAb) were used to determine the prevalence of selected V elements on T cells in synovial fluid (SF) from rheumatoid arthritis (RA) patients and in peripheral blood (PB) from RA patients and normal controls. V_α2-positive PB and SF T cells from 1 patient were cloned by immediated limiting-dilution and analyzed by restriction mapping. Results. In 9 of 14 RA patients, SF was enriched in at least 1 of the selected V elements, compared with PB. TCR genes of the V_α2 family were the most frequently overrepresented in the SF (4 patients). The expanded V_α2-positive cells were oligoclonal in SF but heterogeneic in PB. Conclusion. Our data showing biased and clonally restricted TCR elements in the rheumatoid joint indicate major histocompatibility complex–restricted antigen recognition, rather than a “superantigen,” in the pathogenesis of RA.     

Selective elimination of synovial inflammatory macrophages in rheumatoid arthritis by an Fcgamma receptor I-directed immunotoxin

OBJECTIVE: To determine whether monocyte/macrophages from rheumatoid arthritis (RA) patients can be selectively eliminated by a toxin-conjugated antibody CD64-ricin A (CD64-RiA) directed toward the high-affinity receptor for IgG (FcgammaRI), exploiting the capacity of FcgammaRI to efficiently endocytose antibody which it has bound. METHODS: Mononuclear cells from peripheral blood (PB) and synovial fluid (SF) obtained from RA patients were cultured in the presence of CD64-RiA. Cell death of monocyte/macrophages was measured by phenotypic changes (light-scatter patterns and CD14 and FcgammaRI expression) and apoptosis (nuclear DNA fragmentation). We then tested whether CD64-RiA-induced cell death of macrophages affected their capacity to stimulate antigen-induced lymphocyte proliferation and to secrete cytokines. Additionally, the capacity of CD64-RiA to inhibit proinflammatory activity and cartilage degradation by RA synovial tissue explants was evaluated. RESULTS: Inflammatory macrophages from RA SF expressed elevated levels of FcgammaRI and were selectively eliminated by CD64-RiA via apoptotic cell death. Monocyte/macrophages from RA PB, which had lower levels of FcgammaRI expression, were much less affected. Induction of SF macrophage apoptosis was associated with efficient inhibition of antigen-induced lymphocyte proliferation and a reduction in tumor necrosis factor alpha (TNFalpha) release. Consistent with these effects on SF macrophages, CD64-RiA also inhibited TNFalpha production, interleukin-1beta production, and cartilage-degrading activity of RA synovial tissue explants. CONCLUSION: Together, these data underscore the crucial role of synovial macrophages in RA joint inflammation and indicate that selective elimination of these cells through FcgammaRI-directed immunotoxins could be a novel approach to the treatment of RA.     

Spontaneously increased B cell growth factor and B cell differentiation factor activities in the synovial fluid of patients with rheumatoid arthritis.

The presence of factors implicated in B cell proliferation and differentiation was studied in synovial fluid (SF) from patients with rheumatoid arthritis (RA) and from patients with ankylosing spondylitis (AS) and traumatic joint injury. Culture with Staphylococcus aureus Cowan I B cell blasts showed strong B cell growth factor (BCGF) activity in the SF from patients with RA. This BCGF activity was significantly greater than that found in SF from patients with traumatic joint injury and similar to that of patients with AS. The presence of B cell differentiation factor (BCDF) for IgM(mu) in the SF from patients with RA was also demonstrated and was significantly greater than that found in SF from patients with AS and traumatic joint injury. Moreover, a significantly increased BCDF for IgG(gamma) was also found in the SF from patients with RA compared with that observed in those patients with traumatic joint injury, which, however, was similar to that of patients with AS.     

Secretion of anti–citrulline‐containing peptide antibody by B lymphocytes in rheumatoid arthritis

Objective

To understand the regulation of anti–citrulline‐containing peptide antibody (anti‐CCP) production in rheumatoid arthritis (RA), production of anti‐CCP by B cells derived from peripheral blood (PB), bone marrow (BM), and synovial fluid (SF) was examined.

Methods

Purified PB and SF B cells were isolated by negative selection and then cultured in the absence or presence of L–CD40 ligand cells and interleukin‐10 or anti‐CD3–activated T cells. Total IgM and IgM–anti‐CCP were detected after 14 days of culture by enzyme‐linked immunosorbent assay. Enzyme‐linked immunospot assays were performed to analyze the frequency of cells that spontaneously produced IgM–anti‐CCP in BM and SF B cells.

Results

IgM–anti‐CCP autoantibodies were induced in PB B cells from healthy controls and RA patients following coculture with activated T cells or application of the CD40 activation system, whereas no production could be detected when PB B cells were cultured in the absence of a stimulus. SF and BM B cells from anti‐CCP–seropositive RA patients, but not anti‐CCP–seronegative patients, actively produced IgM–anti‐CCP without stimulation. The frequency of spontaneous production of IgM–anti‐CCP among the IgM‐secreting cells ranged from 2.2% to 25%.

Conclusion

These results indicate the presence of B cell precursors for anti‐CCP autoantibodies that are able to produce antibodies upon stimulation in the PB B cell repertoire of healthy controls and patients with RA. In contrast, B cells that actively secreted anti‐CCP were specifically present in the BM and SF compartment of anti‐CCP–seropositive RA patients. The local presence of anti‐CCP–secreting cells in the inflamed joints provides evidence for an antigen‐driven maturation of CCP‐specific B cells at the site of inflammation in RA.

     

Relationship between IgG2b-inducing activity in rheumatoid arthritis synovial fluid and other well-known cytokines and inflammatory mediators

In the present study, we sought to identify the T cell-replacing factor which selectively induces IgG2b antibody formation in lipopolysaccharide-activated mouse spleen cells in vitro and in vivo, and which is present in the synovial fluid (SF) of rheumatoid arthritis (RA) patients. The protein A plaque assay was used to measure IgM, IgG1, IgG2b, and IgG3 plaque-forming cells. An enzyme-linked immunosorbent assay was used to measure interleukin-6 (IL-6) levels in RA SF. We found that IgG2b induction by RA SF is not caused by IL-6, IL-1, or any other inflammatory cytokines or mediators, such as transforming growth factor beta, platelet-derived growth factor, nerve growth factor, fibroblast growth factor, epidermal growth factor, elastase, collagenase, and phospholipase A2. IgG2b-inducing factor in RA SF has unique biological properties compared with those of the interleukins and inflammatory mediators known to be present in RA SF.     

Immunoglobulins, anti-IgG antibodies and antinuclear antibodies in paired serum and synovial fluid samples. A comparison between juvenile and adult rheumatoid arthritis

Paired samples of serum and synovial fluid (SF) from 13 patients with juvenile rheumatoid arthritis (JRA) and 10 patients with adult rheumatoid arthritis (RA) were examined regarding the level of immunoglobulins and the occurrence and titres of anti-IgG antibodies and antinuclear antibodies (ANA). The levels of immunoglobulins were lower in SF than in serum. In JRA the SF/serum ratio of IgG was equal to that of albumin, pointing to a local production of IgG. The SF/serum ratio of IgM was equal to that of alpha 2-macroglobulin. In JRA the SF/serum ratios of immunoglobulins tended to be lower than in RA, the difference being significant for IgM. IgD autoantibodies and IgA anti-IgG were not found in JRA. IgE autoantibodies occurred in some cases, but in RA in more than 60%. In JRA the SF titres of anti-IgG and ANA were most often lower than the serum titres. In RA the SF titres were often higher than the serum titres. In 9 of 10 paired SF samples from patients with RA the SF/serum ratios were mutually different with regard to one or several immunoglobulins. Evidence of synovial production of anti-IgG antibodies of classes other than IgG distinguished RA from JRA. Otherwise the differences were quantitative.     

Expression of L-Selectin,CD43, and CD44 in Synovial Fluid Neutrophils from Patients with Inflammatory Joint Diseases

Objective. To study the expression of L-selectin, CD43, and CD44 on peripheral blood (PB) and synovial fluid (SF) neutrophils from patients with inflammatory joint diseases, and to investigate the presence of soluble L-selectin in both SF and plasma from patients with acute and chronic arthritis. Methods. PB and SF neutrophils were isolated from 13 patients with rheumatoid arthritis (RA) and 17 patients with various inflammatory joint diseases other than RA. Expression of L-selectin, CD43, CD44, CD11a, and CD11b was determined in both unstimulated and in vitro—activated cells by immunofluorescence flow cytometry. Soluble L-selectin levels were estimated in SF and plasma by a semiquantitative radioimmunoassay. Results. Neutrophils from SF showed diminished expression of L-selectin compared with PB neutrophils; CD43 expression and CD44 expression were decreased in SF neutrophils from most patients. In contrast, SF neutrophils exhibited significantly increased expression of CD11b, to an extent similar to that seen with in vitro—activated PB neutrophils. Soluble L-selectin was detected at similar levels in SF and PB. Conclusion. The phenotypic profile of SF neutrophils (low levels of L-selectin, CD43, and CD44, and high levels of CD11b) from most patients with RA or other inflammatory joint conditions resembles that observed in in vitro—activated neutrophils. Our results suggest that SF neutrophils are activated to a similar degree in inflammatory joint diseases with different pathogenic mechanisms.