Altered lymphocyte reactivity in rheumatoid arthritis

The proteasome inhibitor bortezomib drastically affects inflammation and bone disease in adjuvant-induced arthritis in rats

OBJECTIVE

To explore the effect of bortezomib in splenocytes and fibroblast-like synoviocytes (FLS) and its in vivo potency in a rat model of adjuvant-induced arthritis (AIA), which resembles human rheumatoid arthritis (RA).

METHODS

AIA was induced with Freund's complete adjuvant. Splenocyte and FLS proliferation and apoptosis were measured by radioactivity incorporation and flow cytometry, respectively. The invasiveness of FLS from rats with AIA was tested in a Transwell system. The pattern of cytokine secretion was evaluated by cytometric bead array in splenocyte supernatants. Bortezomib was administered prophylactically or therapeutically, and arthritis was assessed clinically and histologically. Immunohistochemistry was performed for markers of inflammation and angiogenesis in joints. Hematologic and biochemical parameters were tested in peripheral blood (PB). Representative animals were examined by computed tomography (CT) scanning before and after bortezomib administration. The expression of Toll-like receptor 2 (TLR-2), TLR-3, and TLR-4 in PB and FLS was measured by real-time polymerase chain reaction, and alterations in specific cell populations in PB and spleen were determined by flow cytometry.

RESULTS

In vitro, bortezomib exhibited significant inhibitory and proapoptotic activity in splenocytes and FLS from rats with AIA, altered the inflammatory cytokine pattern, and reduced the invasiveness of FLS from rats with AIA. In vivo, bortezomib significantly ameliorated disease severity. Remission was associated with improved histology and decreased expression of CD3, CD79a, CD11b, cyclooxygenase 1, and factor VIII in target tissues as well as down-regulation of TLR expression in PB and cultured FLS. CT scanning demonstrated a bone healing effect after treatment.

CONCLUSION

Our findings suggest that bortezomib affects AIA in a pleiotropic manner and that this drug may be effective in RA.

Altered microRNA expression profile with miR-146a upregulation in CD4+ T cells from patients with rheumatoid arthritis

Introduction

Increasing evidence indicates that microRNAs (miRNAs) play a critical role in the pathogenesis of inflammatory diseases. The aim of the study was to investigate the expression pattern and function of miRNAs in CD4⁺ T cells from patients with rheumatoid arthritis (RA).

Methods

The expression profile of miRNAs in CD4⁺ T cells from synovial fluid (SF) and peripheral blood of 33 RA patients was determined by microarray assay and validated by qRT-PCR analysis. The correlation between altered expression of miRNAs and cytokine levels was determined by linear regression analysis. The role of miR-146a overexpression in regulating T cell apoptosis was evaluated by flow cytometry. A genome-wide gene expression analysis was further performed to identify miR-146a-regulated genes in T cells.

Results

miRNA expression profile analysis revealed that miR-146a expression was significantly upregulated while miR-363 and miR-498 were downregulated in CD4⁺ T cells of RA patients. The level of miR-146a expression was positively correlated with levels of tumor necrosis factor-alpha (TNF-α), and in vitro studies showed TNF-α upregulated miR-146a expression in T cells. Moreover, miR-146a overexpression was found to suppress Jurkat T cell apoptosis. Finally, transcriptome analysis of miR-146a overexpression in T cells identified Fas associated factor 1 (FAF1) as a miR-146a-regulated gene, which was critically involved in modulating T cell apoptosis.

Conclusions

We have detected increased miR-146a in CD4⁺ T cells of RA patients and its close correlation with TNF-α levels. Our findings that miR-146a overexpression suppresses T cell apoptosis indicate a role of miR-146a in RA pathogenesis and provide potential novel therapeutic targets.

Therapeutic T-cell manipulation in rheumatoid arthritis: past, present and future

Accumulating evidence suggests that RA is a T-cell-mediated autoimmune disease. Early attempts at disease modulation using strategies such as CD4 mAbs were severely hampered by a lack of biomarkers of autoreactivity. Recently, however, co-stimulation blockade has emerged as an effective treatment for RA. Alongside a greatly improved mechanistic understanding of immune regulation, this has rekindled hopes for authentic and robust immune programming. The final pieces of the jigsaw are not yet in place for RA but, in other disciplines, emerging treatment paradigms such as non-mitogenic anti-CD3 mAbs, autoantigenic peptides and even cellular therapies are providing hope for a future in which immunopathology can be specifically and vigorously curtailed.

Responses of lymphocytes of patients with rheumatoid arthritis to IgG modified by oxygen radicals or peroxynitrite

OBJECTIVE

We have previously demonstrated the presence of IgG aggregates modified by oxygen radicals (chlorinated IgG [Cl-IgG]) and peroxynitrite (nitrated IgG [N-IgG]) in synovial fluid of patients with rheumatoid arthritis (RA). A possible explanation for the longstanding chronic inflammatory process in RA is the establishment of an immune response to autoantigens. This study was undertaken to examine whether a T cell response to oxidatively modified IgG contributes to the inflammation in RA.

METHODS

We studied in vitro lymphocyte proliferation and interleukin 2 (IL-2) secretion in response to a common antigen (mumps), N-IgG, Cl-IgG, and heat-aggregated IgG (H-IgG) (control) in 15 normal blood donors and 16 RA patients not receiving immunosuppressive drugs.

RESULTS

The responses of RA lymphocytes to mumps antigen were significantly lower that those in controls (mean +/- SEM 2,577 +/- 217 versus 6,367 +/- 365 counts per minute/well; P < 0.02). However, whereas in normal donors the cell responses to N-IgG and Cl-IgG were not significantly different than responses to H-IgG (N-IgG/H-IgG ratio 1.2 +/- 0.2, Cl-IgG/H-IgG 1.5 +/- 0.2), the RA lymphocyte responses to N-IgG and Cl-IgG were significantly higher than the responses to H-IgG (N-IgG/H-IgG 7.4 +/- 2.5, Cl-IgG/H-IgG 4.8 +/- 1.2). When ratios in RA cells were compared with normal cell responses as a group, there was a significant difference for both N-IgG (P < 0.017) and Cl-IgG (P < 0.014). When selected normal and RA lymphocyte culture supernatants were assayed for IL-2 secretion, the increase in IL-2 never exceeded 2-fold in normal cell cultures incubated with any of the IgG compared with unstimulated cultures, whereas responses of RA cells, particularly those incubated with N-IgG, were increased (range 2.6-15.7-fold) compared with unstimulated controls.

CONCLUSION

These results suggest that in RA there are circulating T cells that are responsive to oxidatively modified IgG, a possible pathogenic mechanism contributing to the chronic inflammatory process within the inflamed joint.

Effect of type II collagen treatment on the antioxidant status in immune tissues of adjuvant induced arthritic rats

Adjuvant induced arthritis (AIA) is a model widely used to study Rheumatoid arthritis (RA). In the present study, lipid peroxides level in spleen and thymus of AIA rats was observed to be significantly high compared to normal rats. A significant decrease in ascorbic acid (ASA), reduced glutathione (GSH), superoxide dismutase activity (SOD) was also observed in spleen and thymus of AIA rats compared to normal rats. There was also a steady increase in the circulating immune complex level (CIC) throughout the experimental period in serum of AIA rats. In the present investigation, it was decided to study the effect of pre and post treatment with TYPE II collagen on the antioxidant status and the circulating immune complex level in AIA rats. The results from the present work indicates that the pretreatment with TYPE II collagen was effective in bringing significant changes on all the parameters studied in AIA rats. The post treatment with TYPE II collagen was effective in bringing significant changes on the CIC immune complex level and GSH content in the thymus tissue of AIA rats. The present work suggests that the pre treatment with TYPE II collagen was more effective in suppressing the disease than the post treatment.

Simultaneous analysis of T cell clonality and cytokine production in rheumatoid arthritis using three-colour flow cytometry

In this study we examined the cytokine production by T cells and TCRVbeta subsets in peripheral blood (PB) and synovial fluid (SF) from six RA patients and PB from 10 normal subjects, using three-colour flow cytometry. In two RA subjects we assessed T cell clonality by RT PCR using TCRBV family-specific primers and analysed the CDR3 (complementarity determining region 3) length by GeneScan analysis. A high percentage of IFN-gamma- and IL-2- producing cells was observed among the PB T cells in both the RA patients and normal controls and among the SF T cells in RA patients. In contrast, the percentage of T cells producing IL-4 and IL-5 was small among PB T cells in both RA patients and normal controls and among SF T cells in RA patients. There was no significant difference in the production of IFN-gamma, IL-2 and IL-5 between the two compartments (PB and SF); however, there were significantly more IL-4-producing cells in SF. Molecular analysis revealed clonal expansions of four TCRBV families in SF of two of the RA patients studied: TCRBV6.7, TCRBV13.1 and TCRBV22 in one and TCRBV6.7, TCRBV21.3 and TCRBV22 in the second. These expansions demonstrated cytokine expression profiles that differed from total CD3+ cells, implying that T cell subsets bearing various TCR-Vbeta families may have the potential to modulate the immune response in RA patients.

Increased peripheral T cell reactivity to microbial antigens and collagen type II in rheumatoid arthritis after treatment with soluble TNFalpha receptors

OBJECTIVE

Peripheral T cells from patients with rheumatoid arthritis (RA) are hyporesponsive when stimulated with antigen or mitogen in vitro, possibly owing to increased production of proinflammatory cytokines such as tumour necrosis factor alpha (TNFalpha). This study sought to find out if and how RA T cell reactivity is affected during treatment with etanercept (Enbrel), a soluble TNFalpha receptor.

METHODS

Heparinised blood was collected from patients with RA at baseline, after four and eight weeks of etanercept treatment, and from healthy controls. After density separation spontaneous production of interferon gamma (IFNgamma), TNFalpha, interleukin 6 (IL6), and IL10 by peripheral blood mononuclear cells (PBMC) was detected by ELISPOT. For detection of T cell reactivity, PBMC were stimulated in vitro with mitogen (phytohaemagglutinin (PHA)), microbial antigens (purified protein derivative (PPD), influenza), or an autoantigen, collagen type II (CII). Supernatants were analysed for IFNgamma and IL2 content by enzyme linked immunosorbent assay (ELISA).

RESULTS

In RA the number of cells spontaneously producing IFNgamma was significantly increased after four, but not eight weeks' treatment with etanercept. T cell reactivity, as measured by IFNgamma production to PPD, influenza, and CII was significantly increased after four and sustained after eight weeks' treatment, whereas IFNgamma production induced by PHA remained unchanged. TNFalpha production was significantly higher in patients with RA than in controls and did not change during etanercept treatment.

CONCLUSION

Treatment of patients with RA with etanercept may lead to increased peripheral T cell reactivity both to microbial antigens and to self antigens such as CII. These findings indicate that TNFalpha blockade may not only suppress but also stimulate certain aspects of antimicrobial immune defence and autoimmunity.

Rheumatoid arthritis synovial T cells regulate transcription of several genes associated with antigen-induced anergy

Rheumatoid arthritis (RA) is a chronic, inflammatory synovitis whose pathogenesis may involve autoimmune mechanisms. Anergy is a state of T-cell nonresponsiveness characterized by downregulated IL-2 production. Paradoxically, RA T cells are hyporesponsive and proliferate poorly to antigens and mitogens, thus sharing some characteristics with anergic T cells. We analyzed the molecular basis of anergy in cloned human CD4+ T cells using differential display RT-PCR and subsequently examined the levels of differentially expressed transcripts in RA and, as control, reactive arthritis (ReA) synovium. Several transcriptional events were common to anergic T cells and RA synovium. These included downregulation of CALMODULIN:, which is critical to T-cell activation, and of cellular apoptosis susceptibility protein, which may mediate resistance to apoptosis in RA. Transcription of CALMODULIN: in RA synovium was less than 1% of that in ReA and was lower in RA synovial fluid mononuclear cells than in paired PBMCs. Following anti-TNF-alpha therapy in vivo, RA PBMC CALMODULIN: transcripts increased five- to tenfold. Pharmacological calmodulin blockade in vitro impaired antigen-specific proliferation. These data provide a link between reduced CALMODULIN: transcription and impaired T-cell responsiveness in RA. The identification of transcriptional changes common to anergic and RA synovial T cells should help interpret some of the characteristic RA cellular defects.

Down-regulation of the T cell receptor CD3 zeta chain in rheumatoid arthritis (RA) and its influence on T cell responsiveness

T cells implicated in chronic inflammatory diseases such as RA respond weakly when stimulated in vitro with mitogen or antigen. The mechanism behind this hyporesponsiveness is unclear, but a depressed expression of the T cell receptor (TCR)-associated CD3zeta chain has been suggested. In the present work we describe a low expression of CD3zeta in synovial fluid (SF) T cells from RA patients compared with peripheral blood (PB) T cells, but no difference in CD3zeta expression between RA and healthy control PB T cells. In vitro studies demonstrated that granulocytes but not SF macrophages are able to down-regulate the expression of CD3zeta. Through stimulation with anti-CD3 antibodies we demonstrated that the TCR-dependent proliferative response was decreased in SF T cells compared with PB T cells. Stimulation with phorbol ester and ionomycin also resulted in a low proliferative response of SF T cells, indicating that both signal transduction through the TCR (stimulation with anti-CD3) and events further downstream in the signalling pathways (stimulation with phorbol ester and ionomycin) are affected. A similar depression of T cell activity was observed when induction of IL-2 and IL-4 was measured. However, SF T cells were not defective in the induction of interferon-gamma (IFN-gamma) when stimulated with phorbol myristate acetate (PMA)/ionomycin, in contrast to the diminished IFN-gamma response observed after stimulation with anti-CD3. This indicates that the hyporesponsiveness of SF T cells can not be generalized to all T cell functions. The differential response to external stimuli is likely to be of importance for the capacity of SF T cells to influence inflammatory reactions.

Interferon-gamma production in response to in vitro stimulation with collagen type II in rheumatoid arthritis is associated with HLA-DRB1(*)0401 and HLA-DQ8

INTRODUCTION

Despite much work over past decades, whether antigen-specific immune reactions occur in rheumatoid arthritis (RA) and to what extent such reactions are directed towards joint-specific autoantigens is still questionable. One strong indicator for antigenic involvement in RA is the fact that certain major histocompatibility complex (MHC) class II genotypes [human leucocyte antigen (HLA)-DR4 and HLA-DR1[ predispose for the development of the disease [1]. In the present report, collagen type II (CII) was studied as a putative autoantigen on the basis of both clinical and experimental data that show an increased frequency of antibodies to CII in RA patients [2-4] and that show that CII can induce experimental arthritis [5]. It is evident from the literature that RA peripheral blood mononuclear cells (PBMCs) respond poorly to antigenic stimulation [6-8], and in particular evidence for a partial tolerization to CII has been presented [9]. The strategy of the present work has accordingly been to reinvestigate T-cell reactivity to CII in RA patients, to relate it to the response to commonly used recall antigens and to analyze interferon (IFN)-gamma responses as an alternative to proliferative responses.

AIMS

To study cellular immune reactivity to CII in patients with RA and in healthy control individuals and to correlate this reactivity to HLA class II genotypes and to the presence of antibodies to CII in serum.

METHODS

Forty-five patients who met the 1987 American college of Rheumatology classification criteria for RA [10] and 25 healthy control individuals of similar age and sex were included. Twenty-six of these patients who had low levels of anti-CII in serum were randomly chosen, whereas 19 patients with high anti-CII levels were identified by enzyme-linked immunosorbent assay (ELISA)-screening of 400 RA sera. Heparinized blood was density gradient separated and PBMCs were cultured at 1 x 10(6)/ml in RPMI-10% fetal calf serum with or without antigenic stimulation: native or denatured CII (100 microgram/ml), killed influenza virus (Vaxigrip, Pasteur Merieux, Lyon, France; diluted 1:1000) or purified protein derivative (PPD; 10 microgram/ml). CII was heat-denatured in 56 degrees C for 30 min. Cell supernatants were collected after 7 days and IFN-gamma contents were analyzed using ELISA. HLA-DR and HLA-DQ genotyping was performed utilizing a polymerase chain reaction-based technique with sequence-specific oligonucleotide probe hybridization. Nonparametric statistical analyses were utilized throughout the study.

RESULTS

PBMCs from both RA patients and healthy control individuals responded with IFN-gamma production to the same degree to stimulation with native and denatured CII (Fig. 1a), giving median stimulation indexes with native CII of 4.6 for RA patients and 5.4 for health control individuals, and with denatured CII of 2.9 for RA patients and 2.6 for healthy control individuals. RA patients with elevated levels of anti-CII had a weaker IFN-gamma response to both native and denatured CII that did healthy control individuals (P-).02 and 0.04, respectively). Stimulation with the standard recall antigens PPD and killed influenza virus yielded a median stimulation index with PPD of 10.0 for RA patients and 51.3 for healthy control individuals and with influenza of 12.3 for RA patients and 25.7 for healthy, control individuals. The RA patients displayed markedly lower responsiveness to both PPD and killed influenza virus than did healthy control individuals (Fig. 1b). IFN-gamma responses to all antigens were abrogated when coincubating with antibodies blocking MHC class II. The low response to PPD and killed influenza virus in RA patients relative to that of healthy control individuals reflects a general downregulation of antigen-induced responsiveness of T cells from RA patients [6-8]. That no difference between the RA group and the control group was recorded CII-induced IFN-gamma production therefore indicates that there may be an underlying increased responsiveness to CII in RA patients, which is obscured by the general downregulation of T-cell responsiveness in these patients. In order to address this possibility, we calculated the fraction between individual values for the CII-induced IFN-gamma production and the PPD-induced and killed influenza virus-induced IFN-gamma production and the PPD-induced and killed influenza virus-induced IFN-gamma production, and compared these fractions. A highly significant difference between the RA and health control groups was apparent after stimulation with both native CII and denatured CII when expressing the response as a fraction of that with PPD (Fig. 2a). Similar data were obtained using killed influenza virus-stimulated IFN-gamma values as the denominator (Fig. 2b).When comparing the compensated IFN-gamma response to denatured CII stimulation between RA patients with different HLA genotypes, highly significant differences were evident, with HLA-DRB1*0401 patients having greater CII responsiveness than patients who lacked this genotype (Fig. 3a). HLA-DQ8 positive patients also displayed a high responsiveness to CII as compared with HLA-DQ8 negative RA patients (Fig. 3b). These associations between the relative T-cell reactivity to denatured CII and HLA class II genotypes were not seen in healthy control individuals. Similar results were achieved using influenza as denominator (P = 0.02 for HLA-DRB1*0401 and P = 0.01 for HLA-DQ8).

DISCUSSION

No reports have previously systematically taken the general T-cell hyporesponsiveness in RA into account when investigating specific T-cell responses in this disease. In order to address this issue we used the T-cell responses to PPD and killed influenza virus as reference antigens. This was made on the assumption that exposure to these antigens is similar in age-matched and sex-matched groups of RA patients and healthy control individuals. The concept of a general hyporesponsiveness in RA T cells has been documented in several previous reports, in which both nominal antigens [6,7,8] and mitogens [11,12,13] have been used. The fact that a similar functional downregulation in RA PBMCs was obtained with both PPD and killed influenza virus as reference antigens strengthens the validity of our approach. We identified an association between the IFN-gamma response to CII and HLA-DRB1*0401 and HLA-DQ8 in the RA patient group, which is of obvious interest because both these MHC class II alleles have been associated with high responsiveness to CII in transgenic mice that express these human MHC class II molecules [14,15]. There was no association between high anti-CII levels and shared epitope (HLA-DRB1*0401 or HLA-DRB1*0404).

CONCLUSION

CII, a major autoantigen candidate in RA, can elicit an IFN-gamma response in vitro that is associated with HLA-DRB1*0401 and HLA-DQ8 in RA patients. This study, with a partly new methodological approach to a classical problem in RA, has provided some additional support to the notion that CII may be a target autoantigen of importance for a substantial group of RA patients. Continued efforts to identify mechanisms behind the general hyporesponsiveness to antigens in RA, as well as the mechanisms behind the potential partial anergy to CII, may provide us with better opportunities to study the specificity and pathophysiological relevance of anti-CII reactivity in RA.

Decreased expression of signal-transducing CD3 zeta chains in T cells from the joints and peripheral blood of rheumatoid arthritis patients

Although T cells from patients with rheumatoid arthritis (RA) have previously been determined to have poor proliferative responses to a variety of stimuli, the underlying mechanism is not known. We have investigated the expression of the signal-transducing zeta molecule in subsets of T cells and natural killer (NK) cells derived from the peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) of RA patients using quantitative flow cytometry, Western blot analysis and immunohistochemistry. A decrease of zeta expression was apparent in all investigated lymphocyte subsets from the PBMC and SFMC of RA patients, as compared to the corresponding subsets from healthy age- and sex-matched controls. A less pronounced reduction of cell surface-located CD3 epsilon, CD4 and CD8 was also located in T cells from SFMC as compared to PBMC from RA patients. Biochemical demonstration of the low or absent CD3 zeta in PBMC from patients with RA was achieved by Western blot analysis. Immunohistochemical staining and image analysis also confirmed the low expression of zeta chains in synovial tissue of RA patients. The possibility that the decreased expression of zeta and of immune functions of T cells from RA patients may be related to the presence of free oxygen radicals, as we have previously reported in cancer patients, should be considered.

Bacterial interference with immunospecific defences

There are many descriptions of bacterial agents that can suppress different phases of specific immunity. Bacterial agents are frequently employed as tools to modulate the immune system in experimental models or clinical therapy. Little attention has been given to the implications of such immunoregulating properties for infectious processes or for the natural role of the microbial flora in the normal regulation of the immune system. There are very few studies attempting to investigate directly the possible role of bacterial immunosuppressant factors in acute infection. Several examples of natural and experimental chronic infections have been described in which progressive uncontrolled infection is associated with a depressed cell mediated immunity, but a causal relation is unproven. This depression is usually not antigenically specific and there is some evidence that it may be initiated and maintained by persistent cell-wall components of the microorganisms. The bacteria implicated in suppression are all facultative or obligate intracellular parasites that can multiply and survive in the monocyte/macrophage. Bacterial immunosuppressants may have a crucial role in the pathogenesis of progressive chronic inflammation that occurs after infection.

Role of cytokines in rheumatoid arthritis

Analysis of cytokine mRNA and protein in rheumatoid arthritis tissue revealed that many proinflammatory cytokines such as TNF alpha, IL-1, IL-6, GM-CSF, and chemokines such as IL-8 are abundant in all patients regardless of therapy. This is compensated to some degree by the increased production of anti-inflammatory cytokines such as IL-10 and TGF beta and cytokine inhibitors such as IL-1ra and soluble TNF-R. However, this upregulation in homeostatic regulatory mechanisms is not sufficient as these are unable to neutralize all the TNF alpha and IL-1 produced. In rheumatoid joint cell cultures that spontaneously produce IL-1, TNF alpha was the major dominant regulator of IL-1. Subsequently, other proinflammatory cytokines were also inhibited if TNF alpha was neutralized, leading to the new concept that the proinflammatory cytokines were linked in a network with TNF alpha at its apex. This led to the hypothesis that TNF alpha was of major importance in rheumatoid arthritis and was a therapeutic target. This hypothesis has been successfully tested in animal models, of, for example, collagen-induced arthritis, and these studies have provided the rationale for clinical trials of anti-TNF alpha therapy in patients with long-standing rheumatoid arthritis. Several clinical trials using a chimeric anti-TNF alpha antibody have shown marked clinical benefit, verifying the hypothesis that TNF alpha is of major importance in rheumatoid arthritis. Retreatment studies have also shown benefit in repeated relapses, indicating that the disease remains TNF alpha dependent. Overall these studies demonstrate that analysis of cytokine expression and regulation may yield effective therapeutic targets in inflammatory disease.

Application of 6-hydroxydopamine into the fatpads surrounding the draining lymph nodes exacerbates adjuvant-induced arthritis

Adjuvant-induced arthritis (AA) was examined in Lewis rats following local injection of 6-hydroxydopamine (6-OHDA) into the fatpads of the popliteal and inguinal lymph nodes which drain the hindlimbs (DLN). This method of 6-OHDA treatment resulted in noradrenergic (NA) denervation of DLN, spleen, and other organs in the peritoneal cavity, while sparing NA nerve fibers in the hindlimbs. Sympathectomy exacerbated the inflammation and osteopathic destruction of arthritic joints. Significant increases in dorsoplantar width in arthritic rats following denervation were observed by day 27 following immunization compared to nondenervated arthritic animals. Radiographic evaluation on day 27 after immunization confirmed the inflammation of soft tissue and revealed deterioration of bones of the ankle joint in both AA groups compared with the control groups; more extensive joint damage was apparent in arthritic rats following denervation compared to nondenervated arthritic rats. These findings suggest that the NA innervation of DLN and spleen (and possibly other organs of the peritoneal cavity) plays a regulatory role in the expression of AA. These data supports the hypothesis that absence of NA innervation in lymphoid organs during initiation, onset, and progression of the disease results in exacerbation of AA.

Chronic exposure to tumor necrosis factor (TNF) in vitro impairs the activation of T cells through the T cell receptor/CD3 complex; reversal in vivo by anti-TNF antibodies in patients with rheumatoid arthritis

Experiments were designed to test the hypothesis that chronic exposure to tumor necrosis factor alpha (TNF) alters the function of activated T lymphocytes. Pretreatment of tetanus toxoid-specific T cell clones with TNF for up to 16 d impaired rechallenge proliferative responses to antigen in a dose- and time-dependent fashion. IL-2 and PHA responses were preserved. Prolonged treatment with TNF impaired production of IL-2, IL-10, IFN gamma, TNF, and lymphotoxin (LT) following stimulation with immobilized OKT3, and resulted in suboptimal expression of the IL-2R alpha chain (Tac) but not CD3, CD4, or HLA-DR antigens, when compared to untreated control cells. By contrast, pretreatment of T cells for prolonged periods in vitro with neutralizing anti-TNF monoclonal antibodies (mAb) enhanced proliferative responses, increased lymphokine production, and upregulated Tac expression following stimulation with OKT3. To determine whether TNF exerts immunosuppressive effects on T cells in vivo, we studied cell-mediated immunity in patients with active rheumatoid arthritis (RA), before and after treatment with a chimeric anti-TNF mAb. Treatment with anti-TNF restored the diminished proliferative responses of PBMC to mitogens and recall antigens towards normal in all patients tested. These data demonstrate that persistent expression of TNF in vitro and in vivo impairs cell-mediated immune responses.

The effect of prostaglandin E2 and indomethacin on the cytotoxic response to mycobacterial antigens

The effect of prostaglandin E2 and indomethacin on the generation of cytotoxic T-lymphocytes in response to Mycobacterium tuberculosis (MTB) antigens was compared between healthy controls and rheumatoid arthritis patients. Peripheral blood mononuclear cells (PBMC) from 16 healthy individuals and 15 RA patients were stimulated for 7 days with an irradiated, sonicated preparation of MTB in the presence or absence of PGE2 or indomethacin and assayed for cytotoxic activity on autologous target cells prepulsed with MTB. The mean cytotoxic activity generated was lower in patients than in controls. Exogenous PGE2 suppressed the cytotoxicity directed against MTB pulsed targets in 12 of 16 controls, but in only 1 of 11 patients. Indomethacin enhanced this cytotoxicity in only 2 of 16 controls but in 6 of 10 RA patients. When effector cells were derived from the synovial fluid, PGE2 again had no effect and indomethacin enhanced the cytotoxicity. Our data suggest that the depressed cytotoxic response of RA patients to MTB may be due to the production of endogenous PGE2. Cyclooxygenase inhibitors commonly used in the treatment of RA may influence MTB induced cytotoxicity in patients. In addition to their anti-inflammatory effects within the joint, non-steroidal anti-inflammatory drugs may potentially enhance cytotoxic reactions which are induced by antigens, such as MTB cross-reactive heat shock proteins.

Immunoregulatory role of interleukin 10 in rheumatoid arthritis

The presence and the role of interleukin 10 (IL-10), a potent cytokine synthesis inhibitory factor and antiinflammatory cytokine, were investigated in rheumatoid arthritis (RA). The expression of both mRNA and protein for IL-10 could be demonstrated in RA and osteoarthritis (OA) joints. Human IL-10 mRNA could be demonstrated by polymerase chain reaction amplification of cDNA made by reverse transcription of total RNA extracted directly from synovial tissue in five out of five RA and four out of five OA patients. IL-10 protein was demonstrated by specific immunoassay and immunohistology. IL-10 protein was spontaneously produced in all 11 RA and 17 OA synovial membrane cultures investigated, and this production was sustained for up to 5 d in culture in the absence of any extrinsic stimulation. IL-10 protein could also be detected by immunohistology in all five RA and four OA synovial membrane biopsies investigated, but not three normal synovial membranes. Immunohistology revealed that the IL-10 was localized to the synovial membrane lining layer and mononuclear cell aggregates. Immunofluorescence double staining revealed that the sources of IL-10 were monocytes in the lining layer, and T cells in the mononuclear cell aggregates. We found evidence that the IL-10 expression was functionally relevant, as neutralization of endogenously produced IL-10 in the RA synovial membrane cultures resulted in a two- to threefold increase in the protein levels of proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and IL-1 beta, although IL-6 and IL-8 levels were not affected. The addition of exogenous recombinant IL-10 to the RA synovial membrane cultures resulted in a two- to threefold decrease in the levels of TNF-alpha and IL-1 beta. IL-8 levels were reduced by day 5; however, IL-6 levels were not affected by exogenous IL-10. Neutralization of the endogenous IL-10 in two out of seven RA synovial membrane cultures resulted in the expression of detectable levels of interferon gamma (561-1,050 pg/ml). Taken together, the above findings suggest that IL-10 is spontaneously produced in RA and OA and is an important immunoregulatory component in the cytokine network of RA, regulating monocyte and in some cases T cell cytokine production.

Defective signal transduction via T-cell receptor-CD3 structure in T cells from rheumatoid arthritis patients

T cells from patients with active RA are known to produce low levels of IL-2 and proliferate poorly in response to various mitogenic stimuli. The present work shows that cross-linking of CD3 antigen on patients' T-cell surface induces two- to threefold lower Ca2+ response than in T cells from age-matched controls. Immunofluorescence studies indicate that the attenuated signal may be due to the suppressed expression of CD3 and/or CD45 molecules on patients' T cells. In the majority of the patients, the level of CD45 expression is reduced by 60%-70% as compared with that in the control T cells. Therefore, the poor mitogenic response of patient cells is apparently due to a defect in early stages of signal transduction through the T-cell receptor (TCR-CD3).

Modulation of human T cell functions by surface sulphydryl groups: differential effects on IL-2 production and responsiveness

An impermeable thiol blocker has been used to investigate the role of sulphydryl (SH) groups in the production of and responsiveness to IL-2 by normal human T lymphocytes. Surface SH blockade of mononuclear cells prior to incubation with mitogen (phytohaemagglutinin, concanavalin A, CD3 MoAb) had no effect on production of IL-2 but markedly impaired cellular responsiveness to exogenous IL-2. Studies using MoAbs indicated that this effect was accompanied by decreased expression of both the CD25 and p75 subunits of the IL-2 receptor. Blocking surface SH groups did not affect binding of IL-2 to p75 on unstimulated mononuclear cells, but inhibited binding to high-affinity receptors on a T lymphoma cell line. The data are consistent with the hypothesis that sulphydryl groups on the IL-2 receptor are required for its function and may be involved in the interaction of the CD25 and p75 subunits leading to generation of the high-affinity binding site. The surface thiol identified on the IL-2 receptor may be a candidate for oxidation on cells from patients with chronic inflammatory diseases such as rheumatoid arthritis and thus contribute to the aberrant function of T cells in these patients.

Transforming growth factor beta 1 (TGF-beta 1) induced neutrophil recruitment to synovial tissues: implications for TGF-beta-driven synovial inflammation and hyperplasia

We have studied the consequences of introducing human recombinant transforming growth factor beta 1 (hrTGF-beta 1) into synovial tissue of the rat, to begin to better understand the significance of the fact that biologically active TGF-beta is found in human arthritic synovial effusions. Within 4-6 h after the intra-articular injection of 1 microgram of hrTGF-beta 1 into rat knee joints, extensive recruitment of polymorphonuclear leukocytes (PMNs) was observed. Cytochemistry and high resolution histological techniques were used to quantitate the influx of PMNs, which peaked 6 h post-injection. In a Boyden chamber assay, hrTGF-beta 1 at 1-10 fg/ml elicited a chemotactic response from PMNs greater in magnitude than that evoked by FMLP, establishing that TGF-beta 1 is an effective chemotactic agent for PMNs in vitro as well as in vivo. That PMNs may represent an important source of TGF-beta in inflammatory infiltrates was strongly suggested by a demonstration that stored TGF-beta 1 was secreted during phorbol myristate acetate-stimulated degranulation in vitro. Acid/ethanol extracts of human PMNs assayed by ELISA contained an average of 355 ng of TGF/beta 1 per 10(9) cells potentially available for secretion during degranulation of PMNs. [3H]Thymidine incorporation in vivo and autoradiography of tissue sections revealed that widespread cell proliferation was triggered by TGF-beta 1 injection. Synovial lining cells and cells located deep within the subsynovial connective tissue were identified as sources of at least some of the new cells that contribute to TGF-beta 1-induced hyperplasia. Our results demonstrate that TGF-beta is capable of exerting pathogenic effects on synovial tissue and that PMNs may represent a significant source of the TGF-beta present in synovial effusions.

Activation pathways of synovial T lymphocytes. Expression and function of the UM4D4/CDw60 antigen

Accumulating evidence implicates a central role for synovial T cells in the pathogenesis of rheumatoid arthritis, but the activation pathways that drive proliferation and effector function of these cells are not known. We have recently generated a novel monoclonal antibody against a rheumatoid synovial T cell line that recognizes an antigen termed UM4D4 (CDw60). This antigen is expressed on a minority of peripheral blood T cells, and represents the surface component of a distinct pathway of human T cell activation. The current studies were performed to examine the expression and function of UM4D4 on T cells obtained from synovial fluid and synovial membranes of patients with rheumatoid arthritis and other forms of inflammatory joint disease. The UM4D4 antigen is expressed at high surface density on about three-fourths of synovial fluid T cells and on a small subset of synovial fluid natural killer cells; in synovial tissue it is present on more than 90% of T cells in lymphoid aggregates, and on approximately 50% of T cells in stromal infiltrates In addition, UM4D4 is expressed in synovial tissue on a previously undescribed population of HLA-DR/DP-negative non-T cells with a dendritic morphology. Anti-UM4D4 was co-mitogenic for both RA and non-RA synovial fluid mononuclear cells, and induced IL-2 receptor expression. The UM4D4/CDw60 antigen may represent a functional activation pathway for synovial compartment T cells, which could play an important role in the pathogenesis of inflammatory arthritis.

Methotrexate therapy in rheumatoid arthritis patients diminishes lectin-induced mononuclear cell proliferation

Methotrexate (MTX) is an anti-folate drug used in cancer chemotherapy because of its anti-proliferative effects. However, it is unclear whether the anti-proliferative effects of MTX contribute to the efficacy of low-dose MTX in the treatment of rheumatoid arthritis (RA). To date, either no change or a paradoxical increase in lectin-induced proliferation has been observed in cultures of peripheral blood mononuclear cells (PBMC) from MTX-treated RA patients (RA + MTX). In these earlier studies, high folate-containing media and tritiated thymidine (3H-TdR) were used. Our studies were designed to test the hypothesis that the use of a culture medium with a low folate content along with tritiated deoxyuridine (3H-UdR) permits detection of diminished phytohemagglutinin (PHA)-induced proliferative responses of PBMC from RA + MTX. The data demonstrate decreased PHA-induced cellular proliferation of cultured PBMC from RA + MTX compared with controls. When comparing the PBMC proliferative responses in high vs low folate medium, a significantly greater increase (P less than 0.05) in proliferation occurs in the cells from RA + MTX cultured in the high folate medium. This suggests that an in vivo folate-deficient state of the cells from RA + MTX may be corrected in vitro when a high folate medium is used in culture. We conclude that the use of 3H-UdR and a medium containing folate within the normal range of plasma folate levels eliminates artifacts associated with the use of high folate medium and 3H-TdR, which obscures the anti-proliferative effect of MTX in RA patients.

Effects of a novel anti-inflammatory retinoid-like 2,4,6,8-nonatetraenoic acid on the immunological changes associated with adjuvant-induced arthritis

Proliferative responses to the T-cell mitogen, Con A, were markedly suppressed in spleen cells isolated from rats 12-16 days following induction of adjuvant-induced arthritis (AA). These responses were only partially restored following removal of plastic-adherent cells (AC-depleted). Prophylactic treatment of AA rats with a novel anti-inflammatory retinoid-like 2,4,6,8-nonatetraenoic acid, Ro 23-6457, increased mitogen-induced proliferative responses in spleen cells, particularly in AC-depleted cultures. Treatment of AA rats with Ro 23-6457 significantly increased Con A-induced IL-2 production by both unseparated and AC-depleted spleen cells. Although exogenous IL-2 did not restore proliferative responses to Con A-stimulated spleen cells from vehicle-treated AA rats, responses in AC-depleted cells from Ro 23-6457-treated AA rats were further enhanced by the addition of IL-2. Following stimulation with LPS, supernatants from cultures of adherent spleen cells isolated from AA rats contained more IL-1 (expressed as units/ml) than cultures from normal rats. Treatment of AA rats with a high dose of Ro 23-6457 normalised IL-1 levels in these cultures. Treatment of normal rats with Ro 23-6457 had no significant effects on any parameter tested. These data suggest that Ro 23-6457's modulation of certain disease-associated alterations in immune function in AA rats may contribute to its anti-inflammatory activity.

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.

Abnormal helper-inducer/suppressor-inducer T-cell subset distribution and T-cell activation status are common to all types of chronic synovitis

We have previously shown that rheumatoid synovial T cells are virtually all helper-inducer (CD4+4B4+UCHL1+) rather than suppressor-inducer (CD4+2H4+) cells. CD8 cells were also largely 4B4+. In addition, the majority of T cells were HLA-DR+. To investigate whether these findings were specific for rheumatoid disease, we studied the prevalence of these markers in a variety of chronic inflammatory arthropathies such as ankylosing spondylitis, Reiter's syndrome, and psoriatic arthritis. Again, almost 90% of the T cells were 4B4+UCHL1+ and only 11% were 2H4+; 50% expressed the HLA DR antigen. Thus this phenotypic distribution represents a final common pathway of chronic synovitis and may help to explain the immunopathology of the lesion.

Phytohaemagglutinin induced proliferation of lymphocytes from patients with rheumatoid arthritis and iron deficiency

The response of peripheral blood lymphocytes to stimulation by mitogens such as phytohaemagglutinin (PHA) is commonly depressed in both rheumatoid arthritis and iron deficiency, and as many rheumatoid patients are anaemic with evidence of abnormal iron metabolism it is possible that the same mechanism underlies the observed suppression in both conditions. In the present study the mitogenic response to PHA of lymphocytes from three rheumatoid patients, who were also iron deficient, and two healthy controls has been shown to be significantly less in iron deficient than iron containing media (p less than 0.001). In addition, iron deficient sera from these patients reduced the PHA induced proliferation of lymphocytes from a normal subject (p less than 0.01), an effect which was prevented by prior addition of iron to these serum samples. In iron containing media lymphocytes from five patients and two controls showed no difference in their response to PHA for both the minimum mitogen concentration which enhanced transformation and the peak [3H]thymidine uptake; but patients' lymphocytes showed significantly less response to PHA concentrations of 5 and 10 mg/l (p less than 0.02), resulting in a reduction in the area under the dose response curves up to 20 mg/l (p less than 0.05). These findings show both that iron deficient sera can impair PHA induced lymphocyte transformation and that lymphocytes from iron deficient rheumatoid patients have impaired responsiveness to PHA. Iron is known to be required intracellularly for the enzyme ribonucleotide reductase, which is important for DNA synthesis, and reduced activity of this enzyme could explain these observed effects.

Dendritic cells in the pathogenesis of rheumatoid arthritis

The cause of rheumatoid arthritis is unknown. It appears that abnormal or overstimulated cell-mediated immune mechanisms are operating. Dendritic cells, with their potent antigen presenting and immunostimulatory properties, have been found in increased numbers of rheumatoid synovial fluids and membranes. It is postulated that these cells play a key role in inducing and perpetuating the immune response with subsequent synovial proliferation and joint destruction.

Basis for defective responses of rheumatoid arthritis synovial fluid lymphocytes to anti-CD3 (T3) antibodies

Synovial fluid mononuclear cells (SFMC) from patients with active rheumatoid arthritis characteristically respond poorly to mitogens. In this study, mitogenic antibodies reactive with the CD3(T3) antigen on human T lymphocytes were used to analyze the basis for the deficiency. OKT3-induced proliferation and release of interleukin 1 (IL-1) and interleukin 2 (IL-2) from SFMC were depressed in all patients. Purified IL-1 or recombinant IL-2 restored proliferative responses in SFMC and increased IL-2 receptor density. Exogenous IL-1 also enhanced IL-2 release. Fractionation of SFMC supernatants on phosphocellulose columns revealed the presence of IL-1 and a potent IL-1 inhibitor. The monocyte-derived IL-1 inhibitor blocked IL-1-dependent responses of normal peripheral blood lymphocytes to OKT3, but had no effect on IL-2-dependent events. These results suggest that IL-1 inhibitor(s) in SFMC impair(s) OKT3-induced mitogenesis by interfering with the effects of IL-1 on T lymphocytes. The net result is deficient IL-2 secretion, IL-2 receptor expression, and impaired cellular proliferation. This novel inhibitory circuit provides a rational explanation for the diminished function of synovial fluid T lymphocytes in rheumatoid arthritis patients.

The role of Ia positive T cells in patients with rheumatoid arthritis

In peripheral blood and synovial fluid of patients with rheumatoid arthritis (RA), increased levels of Ia antigen-positive (Ia+) T cells have been demonstrated. Therefore, we examined these Ia+ T cells in vitro to identify their role in the production of rheumatoid factor (RF) and to study the immunologic abnormalities of RA. When Ia+ T cells from peripheral blood of RA patients were added to pokeweed mitogen (PWM)-non-stimulated autologous B cells, the amount of IgM-RF production was 25.8 +/- 6.4 (mean +/- SE) (p less than 0.001) as compared to 16.0 +/- 4.6 ng/ml (mean +/- SE) in the presence of Ia-T cells. When Ia-OKT4+ cell fractions, obtained by excluding Ia+ T cells from OKT4+ cells, were added to B cells, the increase in IgM-RF production was markedly lower than that obtained with the OKT4+ cell fraction. These results indicate that the helper T cells which induce the production of IgM-RF may derive from the Ia+ OKT4+ cell fraction. B cells from rheumatoid synovial fluid produced IgM-RF levels as high as 102.7 +/- 19.2 ng/ml (mean +/- SE) even without stimulation. When T cells from autologous synovial fluid were added, IgM-RF production was not increased. These data suggest that B cells from RA synovial fluid had already been activated. When synovial fluid T cells were added to B cells from autologous peripheral blood, larger amounts of IgM-RF were produced as compared to experiments in which T cells from peripheral blood were added, suggesting that T cells from synovial fluid induced an enhanced IgM-RF production by B cells.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro stimulation of lymphocytes from patients with rheumatoid arthritis

Peripheral blood lymphocytes from patients with rheumatoid arthritis (RA) and from normal controls were compared in 20 microliters droplet cultures following stimulation with phytohemagglutinin or concanavalin A. The dynamics of proliferation were significantly changed in RA. Higher numbers of cells in culture were needed to achieve the same response. This may explain the low proliferative responses of lymphocytes from some patients with RA, and apparent changes of in vitro suppressor effects, reported by other authors. Diurnal variations of lymphocytes in RA patients were also studied. No differences in the response to mitogen of lymphocytes taken at 7 AM and 7 PM were found.

Identification of immunostimulatory dendritic cells in the synovial effusions of patients with rheumatoid arthritis

Dendritic cells in the circulation are leukocytes that are rich in Ia antigens and that actively stimulate T cell replication. We have identified dendritic cells in the joint effusions of patients with rheumatoid arthritis. By phase-contrast and immunofluorescence microscopy, synovial mononuclear cells contained 1-5% dendritic profiles that were rich in HLA-DR and DQ, had small amounts of C3bi receptor, and lacked a battery of monocyte and lymphocyte markers. These dendritic cells could be enriched to 60-80% purity by cytolytic depletion of monocytes and lymphocytes with a group of monoclonal antibodies (MAb) and complement. By transmission electron microscopy, the dendritic cell processes were bulbous in shape and lacked organelles. The cytoplasm had few lysosomes or endocytic vacuoles but contained a well-developed smooth reticulum that was comparable to that previously described in the Ia-rich interdigitating cells of lymphoid tissues. The growth of sodium periodate-modified T lymphocytes was used as a rapid quantitative assay of accessory cell function. Synovial mononuclear cells were some ten times more active than normal blood cells. Treatment with alpha-Ia MAb and complement ablated stimulatory function. In contrast, removal of monocytes (MAb, 3C10) or monocytes and B (MAb, BA-1) plus T (MAb, OKT3, or T101) lymphocytes did not significantly alter total activity, and the function per viable cell increased four- to eightfold. We conclude that rheumatoid arthritis synovial fluids contain cells that are comparable in function, phenotype, and structure to blood dendritic cells, although the frequency (1-5%) is 10 times greater in joints. The reason for their accumulation in the articular cavity is not known, but dendritic cells may be important in perpetuating the joint inflammation characteristic of this disease.

Rheumatoid arthritis and cancer studies based on linking nationwide registries in Finland

Two separate registries that cover the whole population of Finland have been linked in order to study the occurrence of cancer in patients with rheumatoid arthritis. The two registries involved were the Social Insurance Institution's Population Register, which collects information on medication for certain chronic diseases since 1967 including rheumatoid arthritis, and the Finnish Cancer Registry, which has data on all cancer patients in Finland since 1953. The 213,911 person-years' follow-up of 46,101 individuals with rheumatoid arthritis revealed 1,202 cases of cancer. The relative risk of cancer was 1.15 in males and 1.01 in females. The observed number of cases significantly exceeded that expected in Hodgkin's disease, non-Hodgkin's lymphomas, multiple myeloma, and leukemia. In general, the incidence of epithelial tumors was as expected. These findings were further supported by studying the occurrence of subsequent new primary cancers among patients with rheumatoid arthritis and cancer.

Multiple tumor incidence in patients with rheumatoid arthritis or allied disorders

The incidence of multiple malignant neoplasms in 55,279 patients with rheumatoid arthritis (RA) or allied disorders was studied by linking two separate nationwide data registers covering the whole Finnish population. The linking of the Social Insurance Institution's Population Register and the Finnish Cancer Registry resulted in 2106 cancer patients in whom both cancer (diagnosed in 1967-1978) and rheumatoid arthritis or allied disorders (diagnosed before cancer) were diagnosed. In 1974, the allied disorders (ankylosing spondylitis or systemic connective tissue diseases) accounted for 3.9% of all the diagnoses in the Social Insurance Institution's Population Register. The incidence of multiple neoplasms was slightly but not significantly higher in cancer patients with RA or allied disorders than in the general population or in all cancer patients taken together. The risk of leukemia was four times higher in the rheumatoid or allied disease cancer patients than in all the cancer patients. The results are consistent with previous results showing that the leukemia incidence in RA patients is higher than expected.

Lymphoid abnormalities in rats with adjuvant-induced arthritis. I. Mitogen responsiveness and lymphokine synthesis

Lewis rats injected in the hind paw with Mycobacterium butyricum develop a severe polyarthritis which shares certain features in common with rheumatoid arthritis in man. Spleen and peripheral blood mononuclear cells from rats with this form of arthritic disease proliferate poorly in vitro in response to concanavalin A (con A), phytohaemagglutinin (PHA), and pokeweed mitogen (PWM). The splenic hyporesponsiveness appears within four days of M. butyricum injection (three to five days prior to the development of detectable arthritis), reaches a peak 16-22 days following injection, and persists for at least 40 days. Buffalo strain rats injected with M. butyricum do not develop arthritis, and their spleen cells respond normally to con A, PHA, and PWM. In response to lipopolysaccharide (LPS) the synthesis of interleukin 1 (IL-1) by spleen or peritoneal macrophages from arthritic Lewis rats equalled or exceeded that of macrophages from normal rats. In contrast splenic T cells from arthritic rats produced reduced amounts of interleukin 2 (IL-2; T cell growth factor) in response to stimulation with PHA or con A. Moreover, con-A-activated spleen cells from arthritic rats failed to bind IL-2 and to respond to this growth factor with increased 3H-TdR uptake as did normal spleen cells. In-vitro treatment of 'arthritic' cells with 10(-5) M indomethacin did not restore to normal their reduced mitogen responsiveness, and spleen cells from normal and arthritic rats were equally sensitive to the inhibitory effects of prostaglandin E2 on con-A-induced proliferative responses. These results indicate that peripheral lymphoid function is compromised in rats with adjuvant-induced arthritis and that this functional deficit is mediated by aberrant synthesis of and response to IL-2 by T cells of arthritic animals.

Quantitative and qualitative impairment of immunoregulatory cells in the circulation of rheumatoid arthritic patients

T cells bearing receptors for the Fc portion of IgM or IgG, TM or TG cells respectively, in the peripheral blood of RA and OA patients were found significantly less often when compared with TM and TG cells in the peripheral blood of normal donors. Using culture combinations of TM, TG and B cells, we were able to demonstrate that the B cells in the peripheral blood of RA patients were constantly of low functional competence and the TMcells varied between highly competent and low competent. RATG cells in general suppressed normal B-lymphoblast differentiation.

Biologic actions and pharmacokinetic studies of auranofin

The preclinical profiles of auranofin (Ridaura), an oral chrysotherapeutic agent, parenteral gold sodium thiomalate, gold thioglucose, and their respective ligands were compared. Auranofin was more effective than gold sodium thiomalate in suppressing inflammation and stimulating cell-mediated immunity. In contrast to gold sodium thiomalate and gold thioglucose, auranofin inhibited cellular release of lysosomal enzymes, antibody-dependent cellular cytotoxicity, production of antibodies in adjuvant arthritic rats, and antibodies involved in cytotoxicity reactions. The respective ligands were without significant biologic activity. In rats, a higher fraction of gold was associated with blood cells after auranofin administration than after gold sodium thiomalate. The absorption, distribution, metabolism, and excretion of auranofin are uniquely different from other gold compounds.

Characterization of blood mononuclear cells of rheumatoid arthritis patients. II. Depressed PPD presentation by monocytes to T lymphocytes

Purified blood monocytes from patients with rheumatoid arthritis (RA) were significantly less capable of presenting purified protein derivative of tuberculin (PPD) to autologous lymphocytes than monocytes from patients with osteoarthritis, degenerative spine diseases, or healthy controls. Since lymphocytes from RA patients exhibited a normal response to soluble PPD or concanavalin A, the lowered T-cell reactivity had to be attributed to a diminished antigen-presenting capacity of monocytes. Several reasons may be responsible for this altered monocyte function in rheumatoid arthritis: a shift of monocytes to subpopulations expressing less Ia-like antigens, an inherent monocyte disorder, or a "preactivation" of monocytes associated with a reduced antigen-presenting capacity.

Ia specific antilymphocyte antibodies in rheumatoid arthritis

Antilymphocyte antibodies (ALA) in rheumatoid arthritis (RA) have increased reactivity with phytohemagglutinin (PHA) activated lymphoblasts which are known to have increased expression of Ia antigen. The present experiments suggest that part of this reactivity represents an Ia specificity of ALA. Fifteen of 18 RA sera tested were able to inhibit the binding of monoclonal anti-Ia antibodies as measured by a rosette method. RA sera did not inhibit the binding of other monoclonal antibodies: anti-OKT3, anti-OKT4, and anti-OKT8. The ability of RA sera to inhibit the binding of anti-Ia antibody was eliminated after absorption of the RA sera with an Ia positive human cell line (B35M) but not by an Ia negative line (MOLT4). Blocking of anti-Ia binding was greater in the IgG fraction of the RA sera but also occurred in the IgM fraction. Experiments including ultracentrifugation, pepsin digestion of RA sera, and preincubation of lymphoblasts with aggregated IgG demonstrated that Fc binding by RA sera was not a factor. Both monoclonal anti-Ia and anti-Ia heteroantiserum also had increased reactivity with lymphoblast target cells. Pepsin digested Fab fragments of the anti-Ia heteroantiserum were able to block the activity of cytotoxic RA serum. However, ALA cytotoxic to lymphoblasts did not correlate with anti-Ia by rosette method. Ia-specific ALA by rosette method was associated with donor variability but did not appear to be HLA-DR restricted. Ia-specific ALA did correlate with disease activity. These data suggest that anti-Ia activity is present in RA sera and may play an immunoregulatory role in this disease.

Studies of rheumatoid synovial fluid lymphocytes. II. A comparison of their behavior with blood mononuclear cells in the autologous mixed lymphocyte reaction and response to TCGF

Synovial fluid lymphocytes (SFL) and peripheral blood lymphocytes (PBL) from patients with rheumatoid arthritis were compared for their response to lectin stimulation and for their behavior in the autologous mixed lymphocyte reaction (AMLR). The SFL proliferative response to phytohemagglutinin (PHA), as measured by tritiated thymidine incorporation at 72 hr, was lower than that of PBL (P less than 0.001). When T-cell growth factor (TCGF) was added to the medium, there was an increase in the SFL proliferative response to PHA (P less than 0.05). In contrast, TCGF did not alter significantly the PBL proliferative response to PHA. Mixing experiments were performed to determine whether the poor SFL proliferative response was due to passive absorption and removal of in situ-generated TCGF by "suppressor" cells. When cultured together, SFL did not suppress the PBL proliferative response to PHA, suggesting that decreased production of TCGF rather than competitive binding of TCGF results in the poor SFL proliferative response to lectin stimulation. In the AMLR, synovial fluid non-T cells were found to be more stimulatory to peripheral blood T cells than were peripheral blood non-T cells (P less than 0.001). In comparison to peripheral blood T cells, synovial fluid T cells were poor responders in the AMLR. Repetitive in vitro autologous stimulation of peripheral blood T cells resulted in proliferative responsiveness analogous to that of SFL, i.e., a relatively poor proliferative response in the AMLR and a poor response to PHA. The latter could be augmented by TCGF. The SFL requirement for exogenous TCGF is consistent with a state of immune activation. In vivo stimulation by non-T cells may play an important role in the immune activation which characterizes rheumatoid SFL.

Biphasic changes of the immunological reactivity in the course of experimental lectin-induced arthritis of rabbits

A single injection of Lens culinaris lectin (LcL) into the knee joint cavity of non-sensitized rabbits produces an arthritis with an acute and chronic phase, lasting up to one year. The persistence of the lectin in the joint, related to the strong binding affinity of lectins to glycoproteins of connective tissue structures, and the presence of specific antibodies against LcL in the serum after the intra-articular injection make this model comparable to the antigen-induced arthritis. But in our system these conditions are further modified or amplified by the mitogenic activity of LcL itself. The cell-mediated immunity, studied by mitogenic stimulation of peripheral blood lymphocytes, is characterized by a biphasic change in the course of this experimental arthritis. Hyperresponsiveness to stimulation with LcL and Concanavalin A (Con A), decreased Con A-induced suppressor cell activity, and stimulatory serum factors could be detected in the early phase of inflammation. The late phase of arthritis (8 months after the induction) was characterized by hyporesponsiveness to mitogenic stimulation, normal suppressor cell activity and inhibitory serum factors. In spite of the differences of this experimental arthritis to the human rheumatoid arthritis, concerning mainly the initiation and the lack of systemic manifestation, there are surprising similarities between both, not only in the histopathological feature and the chronicity but also in the cell-mediated immune reactions. Therefore, similar pathogenetic mechanisms for the chronic phase can be suggested.

Impaired conA suppressor cell activity in patients with rheumatoid arthritis shows normalization during fasting

Normal controls and patients with rheumatoid arthritis (RA) were investigated with respect to quantitative lymphocyte proliferation (LP) after concanavalin-A (conA) activation and to conA-induced suppressor cell activity (conA-SC). Measurements and assessment of RA activity were made at the beginning and end of a 10-day fast. The controls showed depressed (p less than 0.05) LP at the end of the fast, but no change in conA-SC activity. The RA group showed subnormal (p less than 0.05) LP and conA-SC (p less than 0.01) at the beginning of the experiment. After fasting they showed clinical improvement, the LP was not further depressed, and the initially low conA-SC had become normal.

The pharmacological profile of auranofin, an orally active gold compound

Auranofin (AF; ' Ridaura '), an oral chrysotherapeutic agent, parenteral gold sodium thiomalate (GST) and gold thioglucose (GTG) were evaluated in order to compare their preclinical profiles. AF was found to be more effective than GST and GTG in suppressing inflammation and stimulating cell-mediated immunity. In contrast to GST, AF inhibited cellular release of lysosomal enzymes, antibody-dependent cellular cytotoxicity, production of antibodies in adjuvant arthritic rats, and antibodies involved in cytotoxicity reactions. In pharmacokinetic studies, plasma gold in rats following AF administration, exhibited greater cell association than after GST administration. In conclusion, the pharmacological profile of AF is markedly different from those of GST and GTG and this suggests potential for improvements in chrysotherapy.

In vitro synthesis of immunoglobulins and IgM-rheumatoid factor by blood mononuclear cells of patients with rheumatoid arthritis

In vitro synthesis of IgG, IgM and IgM-rheumatoid factor (IgM-RF) was investigated in unstimulated and pokeweed mitogen (PWM)-stimulated 7-day cultures of blood mononuclear cells (BMC) from 28 seropositive patients with active rheumatoid arthritis (RA), in a second group of 13-day cultures from 94 unselected rheumatoid patients, and in 21 healthy controls. Both normal and rheumatoid BMC cultures synthesized IgM-RF in response to PWM stimulation. Mitogen-induced stimulation was shown to be dependent on the presence of T-lymphocytes. PWM-induced IgM and IgM-RF synthesis were reduced in BMC from rheumatoid patients in comparison with healthy controls. However, the fraction of IgM-RF in the total IgM synthesized was significantly higher in the RA supernatants than in the controls, suggesting the presence of a larger precursor B-cell population committed to IgM-RF synthesis in those cultures. BMC from 44 of the 94 patients demonstrated spontaneous synthesis of IgM-RF, and this was positively correlated with disease activity and rheumatoid factor titer. Spontaneous production was shown to reside in the T-lymphocyte depleted, adherent cell-depleted, B-cell subpopulation. It is concluded that in active RA there is a specific activation and expansion of the circulating B-cell subpopulation committed to IgM-RF synthesis, possibly due to abnormal immunoregulatory mechanisms modulating synthesis of this antibody.

The effect of some antirheumatic drugs in vivo on the response of spleen cells to concanavalin A in rats with chronic inflammation

During the course of adjuvant arthritis in rats adherent spleen cells inhibited the response of spleen lymphocytes to the T-cell mitogen concanavalin A (Con A). The effects of 14 days treatment with various antirheumatic drugs on spleen cell responsiveness to Con A were investigated. Two nonsteroidal anti-inflammatory drugs, indomethacin (1 mg/kg/day p.o.) and acetylsalicylic acid (200 mg/kg/day p.o.) did not modify the spleen cell response, whereas treatment with chloroquine (50 mg/kg/day p.o.) or levamisole (5 mg/kg/day p.o.) further increased the inhibitory effects of the adherent suppressive spleen cells. On the contrary, treatment with sodium aurothiomalate (10 mg/kg/day i.m.), D-penicillamine (50 mg/kg/day p.o.) or pyritinol (50 mg/kg/day p.o.) significantly enhanced the response of the lymphocytes to Con A. In addition to the effects on spleen cell responsiveness, the ability of the various drug treatments to modify the polyarthritic lesions of the disease was investigated. It is suggested that this model may provide a valuable approach for evaluating the effects of antirheumatic drugs in vivo on immunological responsiveness during chronic inflammatory disease.

Cytotoxicity of anti-Fab antibodies against B lymphocytes in rheumatoid arthritis

Anti-Fab antibody titers were positive in 70% of rheumatoid arthritis patients (54 of 77) and 3% (1 of 35) of healthy donors. Their specificity was examined by inhibition of the radioimmunoassay for anti-Fab antibodies, which demonstrated that they are against the Fd region of the intact immunoglobulin molecule. In addition, anti-Fab antibodies have broad specificities for IgG antigens, shown by inhibition with myeloma IgG. They are cytotoxic against B (20% of B cells from most healthy donors) but not T lymphocytes, with cytotoxicity greater at 5 degrees C than 37 degrees C. These studies show that the anti-Fab antibodies interact with allotypic or idiotypic determinants on subpopulations of B lymphocyte cell surface antigens.