Anti-tumor necrosis factor alpha therapy of rheumatoid arthritis. Mechanism of action.
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Arthritis, Rheumatoid↗
Biomedical subjects
R N Maini
Publications and source records attributed to R N Maini.
Cytokine therapy in rheumatoid arthritis.
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Antibodies, Monoclonal↗
Paradoxical effects of a synthetic metalloproteinase inhibitor that blocks both p55 and p75 TNF receptor shedding and TNF alpha processing in RA synovial membrane cell cultures.
We have previously hypothesized that the pro-inflammatory cytokine TNF alpha has a pivotal role in the pathogenesis of rheumatoid arthritis (RA). It mediates its effects by cross-linking surface p55 TNF receptors (TNF-R), which can be proteolytically cleaved to yield soluble fragments. Upon binding TNF alpha soluble TNF-R (sTNF-R) can inhibit its function. We investigated the enzymatic nature of the proteases involved in TNF-R cleavage, and found that this process is blocked by a synthetic inhibitor of matrix metallo-proteinase activity (MMP), BB-2275. Inhibition of TNF-R cleavage was observed in a number of different cell types, as detected by retention of surface bound TNF receptor and by less sTNF-R released into the cell supernatant. The augmentation of surface TNF-R expression was of biological relevance as TNF alpha-mediated necrosis of human KYM.1D4 rhabdosarcoma cells was enhanced approximately 15-fold in the presence of BB-2275. The addition of BB-2275 to rheumatoid synovial membrane cell cultures totally inhibited MMP activity and also significantly reduced the levels of soluble TNF alpha (P < 0.006), p55 sTNF-R (P < 0.006), and p75 sTNF-R (P < 0.004). Paradoxically, despite the reduction in soluble TNF alpha levels, the production of IL-1 beta, IL-6, and IL-8, cytokines whose production was previously demonstrated to be inhibited by the addition of neutralizing anti-TNF alpha antibody were not down-regulated by BB-2275. These results raise the interesting possibility that a close relationship exits between the enzyme(s) which process membrane-bound TNF alpha, and those involved in surface TNF-R cleavage. Furthermore our observations suggest that hydroxamate inhibitors of MMP activity which block TNF alpha secretion and TNF-R cleavage may not modulate down-stream effects of TNA alpha, and as such suggest that the precise specificity of these compounds will be highly relevant to their clinical efficacy in inflammatory diseases.
Arthritis, Rheumatoid↗
Interleukin-10 inhibition of the progression of established collagen-induced arthritis.
OBJECTIVE: Interleukin-10 (IL-10) is a potent inhibitor of the proinflammatory cytokines, including tumor necrosis factor alpha and IL-1, which are considered important in the pathogenesis of rheumatoid arthritis (RA). The study was undertaken to establish whether IL-10 can ameliorate arthritis in the collagen-induced arthritis (CIA) model of RA. METHODS: DBA/1 mice were immunized with bovine type II collagen in adjuvant, and treated daily after disease onset with recombinant murine IL-10 or with saline as a control. Mice were monitored for paw swelling and clinical score. Histologic analysis was also performed. RESULTS: IL-10 treatment of established CIA inhibited paw swelling (P < 0.0001), as well as disease progression as defined by clinical score (P < 0.0002). Cartilage destruction, as assessed histologically, was reduced in IL-10-treated mice compared with controls (P < 0.01). CONCLUSION: IL-10 suppresses established CIA, probably by inhibiting proinflammatory cytokine production. Our results, taken together with previously reported findings, indicate a potential therapeutic role for IL-10 in RA.
Animals↗
Decrease in cellularity and expression of adhesion molecules by anti-tumor necrosis factor alpha monoclonal antibody treatment in patients with rheumatoid arthritis.
OBJECTIVE: The effect of chimeric anti-tumor necrosis factor alpha (TNF alpha) monoclonal antibody (MAb) therapy on synovial inflammation was studied in order to address the hypothesis that anti-TNF alpha therapy leads to down-regulation of adhesion molecules and a decrease in inflammatory cell influx in synovial tissue (ST). METHODS: The immunohistologic features of synovial biopsy specimens, both before and 4 weeks after anti-TNF alpha MAb (cA2) therapy, were studied in 14 patients with rheumatoid arthritis (RA). The patients either received a placebo (n = 2), or were given intravenous doses of cA2 at 10 mg/kg (n = 5) or 20 mg/kg (n = 7). RESULTS: A significant (P < 0.03) reduction in the mean scores for T cells and for the adhesion molecules, vascular cell adhesion molecule 1 and E-selectin, was observed after therapy with 10 mg/kg or 20 mg/kg of cA2 in RA patients. CONCLUSION: The reduced expression of adhesion molecules, and the decrease in cellularity of rheumatoid ST after cA2 administration support the hypothesis that the antiinflammatory effect of anti-TNF alpha therapy might be partly explained by down-regulation of cytokine-inducible vascular adhesion molecules in ST, with a consequent reduction of cell traffic into joints.
Antibodies, Monoclonal↗
Deactivation of vascular endothelium by monoclonal anti-tumor necrosis factor alpha antibody in rheumatoid arthritis.
OBJECTIVE: To assess whether monoclonal antibody to tumor necrosis factor alpha (TNF alpha) reduces endothelial activation in rheumatoid arthritis (RA). METHODS: Levels of serum E-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1), and circulating leukocytes (differential counts) were measured in RA patients before and up to 4 weeks after infusion of either placebo or chimeric anti-TNF alpha antibody cA2 (1 or 10 mg/kg). RESULTS: Treatment with anti-TNF alpha decreased serum E-selectin and ICAM-1 levels, with the earliest detectable changes observed on days 1-3 after anti-TNF alpha infusion. No effect on VCAM-1 levels was detected. In parallel, there was a rapid and sustained increase in circulating lymphocytes. The extent of the decrease in serum E-selectin and ICAM-1 levels and the increase in lymphocyte counts was significantly higher (P < or = 0.05) in patients in whom a clinical benefit of anti-TNF alpha was observed ( > or = 20% response, by Paulus criteria, at week 4) compared with that in patients who failed to respond to anti-TNF alpha at this time point. CONCLUSION: We propose that decreased serum levels of adhesion molecules may reflect diminished activation of endothelial cells in the synovial microvasculature, leading to reduced migration of leukocytes into synovial joints, and thus prolonging the therapeutic effect of anti-TNF alpha in RA.
Antibodies, Monoclonal↗
Placental and fetal cardiac laminin are targets for cross-reacting autoantibodies from mothers of children with congenital heart block.
The association of congenital heart block (CHB) with maternal autoantibodies to the Ro and La ribonucleoprotein antigens may be due to cross-reactions between maternal anti-La antibodies and fetal cardiac specific antigens. One of the major components of cardiac myocytes, laminin, is accessible for binding by maternal autoantibodies and we have previously reported cross-reactivity of mouse laminin with anti-La antibodies affinity purified from the sera of patients with primary Sjögren's syndrome. Affinity purified anti-La antibodies from ten women who had at some time given birth to a child with CHB were examined for cross-reactivity with human placental laminin, which shares structural similarities with cardiac laminin. All ten anti-La antibodies bound to the surface of cryosections of normal full term placental trophoblasts. Binding could be inhibited by pre-incubation of antibodies with either La or placental laminin. Eight anti-La antibodies also reacted with placental laminin by ELISA and La inhibited up to 82% of binding to laminin while laminin inhibited up to 85% of binding to La in a dose dependent manner. Eight anti-La antibodies also bound to the surface of fetal cardiac myocytes at 10.3 weeks of gestation and five showed lower levels of reactivity with the surface of fetal cardiac myocytes at 16.5 weeks of gestation. None showed any surface staining of normal adult heart. These data confirm the cross-reactivity of anti-La antibodies with laminin and may support a placental role in preventing the majority of potentially pathogenic antibodies from reaching the fetal circulation.
Autoantibodies↗
T cell clones from a Sjögren's syndrome salivary gland biopsy produce high levels of IL-10.
Sjögren's syndrome (SS) is characterized by a focal periductal salivary gland infiltrate consisting mainly of T and B lymphocytes. Most of the T cells bear the memory CD4+ Th1-like phenotype and express high levels of class II, though CD8+ cells are also present. We have studied 17 labial salivary gland and 15 peripheral blood T cell clones from a patient with primary SS. The tissue clones were 71% CD8+ and 29% CD4+, and the peripheral blood-derived clones were 60% CD8+ and 40% CD4+. The CD4+ T cell clones from both the salivary gland and autologous peripheral blood were of the Th1 phenotype, in that they produced interferon-gamma (IFN-gamma) and IL-2 but very little IL-4 after 24 h stimulation with phorbol myristate acetate and anti-CD3 antibody. The salivary gland-derived CD4+ clones produced 15 times more IL-10 (7.92 ng/ml) than peripheral blood-derived CD4+ clones (0.52 ng/ml, P < or = 0.02). The tissue CD8+ clones produced 1.2 times (P < 0.04) more IFN-gamma and CD4+ clones produced 3.5 times less IL-2 (P < 0.02) than the respective PBM-derived clones. The accumulation of Th1-type cells producing high levels of IL-10 in the salivary gland suggests a specific immunoregulatory function at the site of inflammation in SS.
Biopsy↗
Analysis of V kappa genes in rheumatoid arthritis (RA) synovial B lymphocytes provides evidence for both polyclonal activation and antigen-driven selection.
To define mechanisms of sustained activation of synovial B lymphocytes in RA, we studied hybridomas established from the local synovial B cell repertoire of two RA patients for V kappa gene expression and for antigen-binding specificity. The analyses revealed that members of the main V kappa families (I, II and III) were utilized at frequencies consistent with random V kappa gene family use. Furthermore, although the hybridomas expressed genes frequently seen in response to other self- and exogenous antigens, only one V kappa I- and two of three V kappa III-expressing hybridomas exhibited reactivity with self-antigens. Nucleotide sequence analysis revealed that all hybridomas, with the exception of rheumatoid factor (RF)-producing hybridomas, expressed V kappa genes highly related to known germ-line genes (99.3-100% homology) and that diversity was generated by deletions and random nucleotide insertions at the V kappa-J kappa junction. Examination of the few nucleotide changes seen with the V kappa genes revealed a predominance of silent to replacement changes. Moreover, most of these changes can be attributable either to allotypic variations or to limited random nucleotide replacements independent of antigen selection. In contrast, one IgG-RF (B4D8) exhibited predominantly replacement nucleotide changes in the complementarity-determining regions, suggestive of antigen-driven selection. The random expression of immunoglobulin variable region genes with no, or little, evidence of mutation in the synovial B lymphocyte repertoire, including natural polyreactive antibodies, alongside mutated IgG-RF, suggest that both polyclonal activation and antigen-driven responses occur in RA synovia.
Amino Acid Sequence↗
The consequences of the Calman Report on academic rheumatology.
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Education, Medical↗
Transfer of type II collagen-induced arthritis from DBA/1 to severe combined immunodeficiency mice can be prevented by blockade of Mac-1.
Collagen-induced arthritis in susceptible mice is widely accepted as an experimental model for human rheumatoid arthritis (RA). We have investigated the role of the Mac-1 integrin beta 2 in the development and maintenance of arthritis by means of in vivo administration of 5C6 monoclonal antibody (mAb) to block this receptor. Injection of a single dose of 5C6 mAb (0.5 mg, intraperitoneally) prior to the expected onset of collagen-induced arthritis in DBA/1 mice diminished the severity of subsequent disease in these animals, as assessed both clinically and histologically (P < 0.01, chi 2). In the DBA/1 to severe combined immunodeficiency (SCID) transfer model of arthritis, the incidence of clinical arthritis was significantly reduced in SCID mice receiving maintained 5C6 treatment commencing the day prior to administration of donor splenocytes. Histological evaluation of joints from animals without clinically evident arthritis confirmed the absence of an inflammatory infiltrate in 22/27 joints examined. In a minority of these joints, however, synovial hyperplasia was apparent. In contrast, delaying antibody administration until 10 days after donor spleen cell transfer failed to protect three of five SCID recipients. These results confirm a functional role for Mac-1 in the generation of collagen-induced arthritis in mice. Since mAb 5C6 is non-cytotoxic, its action must be by blockade of the interactions between Mac-1 and its natural ligand(s). Our findings support the hypothesis that cells expressing Mac-1 play an important role in the induction and maintenance of joint damage in collagen-induced arthritis.
Animals↗
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.
Animals↗
TNF alpha is an effective therapeutic target for rheumatoid arthritis.
Rheumatoid arthritis is the most common of a number of diseases in which inflammation and tissue destruction is driven by an autoimmune process. Current therapy is inadequate, and this has prompted major research efforts, both in academia and industry, to understand more about the pathogenesis, and hence provide the rationale for new therapeutic strategies. Here we review our studies of cytokine expression and regulation in rheumatoid joints, which has culminated in demonstrating that TNF alpha blockade, using a chimeric (human IgG1/K, mouse Fv) anti-TNF alpha antibody, cA2, markedly ameliorates arthritis. This defines a therapeutic target for rheumatoid arthritis.
Animals↗
High level of interleukin-10 production by the activated T cell population within the rheumatoid synovial membrane.
OBJECTIVE: To characterize the cytokine profile of the activated T cell population derived from the synovial membrane of rheumatoid arthritis (RA) patients. METHODS: Interleukin-2 (IL-2) was used to select for in vivo-activated T cells from the synovial membrane of 2 patients with RA, and the cells were cloned nonspecifically. The cytokine production profile of these clones was compared with that of clones derived from peripheral blood monocytes (PBM) by stimulating all clones for 24 hours with immobilized anti-CD3 (coated at 10 micrograms/ml) or phorbol-12-myristate-13-acetate (10 ng/ml) plus soluble anti-CD3 (1 microgram/ml). Interferon-gamma (IFN gamma), IL-4, and IL-10, the cytokines that discriminate between Th1 and Th2 cells and are involved in immunoregulation, were assayed by enzyme-linked immunosorbent assay. RESULTS: There was a difference in the cytokines produced by the clones derived from the rheumatoid membranes compared with clones derived from the periphery. Clones derived from both membranes and PBM were mostly IFN gamma-producers, i.e., either a Th0 or a Th1 profile. There was a high proportion of IFN gamma/high IL-10-producing cells derived from the joint, but not from the periphery. Of clones derived from the synovial membrane of each of 2 RA patients, 100% and 50% produced both 1-10 ng/ml IFN gamma and > 7 ng/ml IL-10, compared with < 7% of clones derived from normal or RA peripheral blood. In addition, when autologous membrane and PBM were compared, the mean concentration of IL-10 produced by the clones derived from the synovial membrane sample was significantly different from those produced by clones derived from peripheral blood (P < 0.02). CONCLUSION: The cytokine profile of the T cell clones that were obtained from the RA joint after expansion with IL-2 is distinct from that of the T cells that are predominant in PBM. This supports the concept that the T cells subsets that accumulate in the joint are not a random sample. The high level of IL-10 production by clones derived from the synovium suggests that this cytokine may be a major contributor to the endogenous immunosuppression that occurs in RA.
Adult↗
The role of the B cells in the adoptive transfer of collagen-induced arthritis from DBA/1 (H-2q) to SCID (H-2d) mice.
Collagen-induced arthritis (CIA) can be transferred from DBA/1 to SCID mice when native type II collagen (CII) is administered together with spleen cells, arthritis appearing some 14 days after cell transfer. In the present study, we demonstrate that both donor T- and B-lymphocyte populations play a role in this model, and that arthritis arises in SCID recipients of either murine or bovine native CII. Furthermore, the requirement for administration of soluble native CII can be replaced by subarthritogenic doses of serum from Wistar rats with CIA. In this case a fully developed arthritis appears as early as 2 days after cell transfer. However, protein G-purified IgG from CIA rat serum together with splenocytes from arthritic DBA/1 mice does not transfer arthritis. A key role of B cells in this model appears to be the production of a humoral arthritogenic factor since arthritis can be successfully transferred to SCID mice by CIA rat serum administered together with a B cell-depleted splenocyte population consisting of T cells and donor-histocompatible antigen-presenting cells. By contrast, transfer of disease cannot be achieved by co-administration of CIA rat serum and purified donor T cells, indicating that the presence of donor antigen-presenting cells is a requirement for adoptive transfer of arthritis. We propose that joint damage initiated by arthritogenic product(s) of the B cell lineage releases soluble antigens that are presented to T cells which perpetuate the disease. The finding that arthritis can be generated in SCID recipients of CIA rat serum together with splenocytes from non-arthritic DBA/1 mice immunized with denatured CII supports the hypothesis that T cells with specificity for denatured joint components perpetuate disease initiated by humoral factors.
Animals↗
TNF alpha blockade in rheumatoid arthritis: rationale, clinical outcomes and mechanisms of action.
Tumor necrosis factor alpha (TNF alpha) is a cytokine with many biological functions of relevance to inflammatory disease. Although only one of several inflammatory mediators produced in abundance in rheumatoid arthritis (RA), experimental data suggest that it is in a dominant position within a cytokine hierarchy and is therefore a prime target for directed immunotherapy in this disease. We have targeted TNF alpha in vivo using a chimerised monoclonal anti-TNF alpha antibody and have now demonstrated beneficial responses to treatment in three different clinical trials. The results confirm that TNF alpha is of central importance in the inflammatory process in RA and define a new treatment strategy in this disease.
Acute-Phase Proteins↗
Anti-cytokine therapy in rheumatoid arthritis.
The past few years have seen an explosion of knowledge concerning the role of cytokines and their naturally occurring inhibitors in the promotion and modulation of inflammatory disease. In RA, this knowledge has been translated into the clinic, with ongoing evaluation of specific cytokine inhibitors, including those targeting tumour necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) and interleukin-6 (IL-6). In this review, we outline the scientific data supporting anti-cytokine therapies in RA and describe the results of published and unpublished clinical trials with biological agents. At least for anti-TNF therapy, short-term clinical efficacy and good tolerability have been confirmed in randomized, placebo controlled trials. The results of IL-1 blockade in vivo also appear encouraging, although detailed descriptions of trail outcomes are awaited. Problems associated with long-term administration of biological agents are discussed, including the development of antiglobulin responses to injected monoclonal antibodies and poor pharmacokinetics of low-molecular-weight inhibitors. Ways of facilitating the long-term use of current biological agents and alternative means for inhibiting cytokine function in future studies in RA are presented.
Animals↗