Anticytokine therapy in rheumatoid arthritis

Current trends in epigenetic, cellular and molecular pathways in management of rheumatoid arthritis

Rheumatoid arthritis is a systemic chronic polyarticular autoimmune disorder of joints and joint membrane mainly affecting feet and hands. The pathological manifestation of the disease includes infiltration of immune cells, hyperplasia of the lining of synovium, formation of pannus and bone and cartilage destruction. If left untreated, the appearance of small focal necrosis, adhesion of granulation, and formation of fibrous tissue on the surface of articular cartilage is noted. The disease primarily affects nearly 1% of the population globally, women being more affected than men with a ratio 2:1 and can initiate regardless of any age. The synovial fibroblast in rheumatoid arthritis individuals exhibits an aggressive phenotype which upregulates the manifestation of protooncogenes, adhesive compounds, inflammatory cytokines and matrix-deteriorating enzymes. Apart from the inflammatory effects of cytokines, chemokines are also noted to induce swelling and pain in arthritic individuals by residing in synovial membrane and forming pannus. The current treatment of rheumatoid arthritis includes treatment with non-steroidal anti-inflammatory drugs, disease-modifying antirheumatic drugs, treatment with biologics such as inhibitors of TNF-α, interleukins, platelet activating factor, etc. which provides significant relief from symptoms and aids in management of the disease. The current review highlights the pathogenesis involved in the onset of rheumatoid arthritis and also covers epigenetic, cellular and molecular parameters associated with it to aid better and advanced therapeutic approaches for management of the debilitating disease.

Serum profile of transferrin isoforms in rheumatoid arthritis treated with biological drugs

BACKGROUND

In the chronic inflammation process in the course of rheumatoid arthritis (RA), many alterations in the expression of plasma proteins, as well as their posttranslational modifications (including glycosylation) can occur. Taking into account the disturbances in protein glycosylation and the emerging new treatment regimens, the aim of this study was to assess the serum profile of transferrin isoforms in RA patients treated with biological drugs.

METHODS

The study included 20 patients (16 females and 4 males; mean age: 53.4 years; range: 24-67) with rheumatoid arthritis treated with rituximab. Serum samples were taken 3 times: before and 3 and 6 months during treatment. The isoforms of transferrin were separated by capillary electrophoresis (MINICAP electrophoretic system, Sebia, France) into five major fractions: asialo-, disialo-, trisialo-, tetrasialo- and pentasialotransferrin. The results were calculated as relative concentrations of each fraction.

RESULTS

The median trisialotransferrin relative concentrations after 3 and 6 months treatment (4.40% and 4.10%, respectively) were significantly higher (p = 0.013, p = 0.009, respectively) than before treatment (3.50%). The levels of serum pentasialotransferrin were also increased 3 and 6 months following treatment (16.5% and 17.7%, p = 0.005 and p = 0.006, respectively) as compared to those before therapy (14.5%), while tetrasialotransferrin concentrations were lower (80.3% and 78.4%, p = 0.009 and p = 0.008, respectively) than before treatment (81.5%). Trisialotransferrin relative concentration correlated with Hb (p = 0.019), whereas pentasialotransferrin with PLT (p = 0.036) after treatment.

CONCLUSIONS

This study indicates that treatment with rituximab of RA patients alters the serum profile of transferrin isoforms. Tri-, tetra- and pentasialotransferrin relative concentrations measurements can be a useful tool to monitor therapy.

Platelet-Rich Plasma Attenuates 30-kDa Fibronectin Fragment-Induced Chemokine and Matrix Metalloproteinase Expression by Meniscocytes and Articular Chondrocytes

BACKGROUND

Proteolytic fragments of fibronectin have catabolic effects on cartilage and menisci. Platelet-rich plasma (PRP) is increasingly being used to treat a range of joint conditions, but it is unknown whether PRP influences fibronectin fragment (FN-f) procatabolic activity.

HYPOTHESES

The procatabolic activity of FN-f on meniscocytes and articular chondrocytes is attenuated by cotreatment with PRP.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human meniscocytes were treated with FN-f (30 kDa) with or without PRP coincubation, and gene expression was analyzed by complementary DNA microarray analysis. Validation of altered expression of known and novel chemokine and protease genes was undertaken by real-time polymerase chain reaction (RT-PCR) in articular chondrocytes and meniscocytes. Chemokine release was assayed by enzyme-linked immunosorbent assay, and intracellular pathway signaling was evaluated by Western immunoblotting.

RESULTS

Microarray analysis and RT-PCR showed increased expression of matrix metalloproteinase (MMP)1, MMP2, MMP3, MMP9, MMP13, interleukin (IL)-6, IL-8 (CXCL8), CCL5, CCL20, and CXCL10 chemokines in meniscocytes after treatment with FN-f. Upregulation of these genes was significantly attenuated by PRP. Similar results were seen with articular chondrocytes, although no changes in MMP2 or MMP9 levels were identified. PRP-induced suppression of gene expression was associated with activation of Akt and p44/p42.

CONCLUSION

PRP treatment attenuates the 30-kDa FN-f-induced expression of a range of proinflammatory chemokines and MMPs, including IL-8, IL-6, CCL20, CCL5, CXCL10, MMP1, MMP3, and MMP13, by both meniscocytes and articular chondrocytes.

CLINICAL RELEVANCE

These observations provide support for the use and further trials of PRP in management of cartilage and meniscal injuries.

Immunologic derangement preceding clinical autoimmunity

Autoantibodies are valuable markers for the recognition of autoimmune diseases. Over the last 25 years, several investigators have consistently shown that autoantibodies precede the clinical onset of cognate diseases by years or decades. This phenomenon, regularly observed in the natural history of autoimmune diseases, indicates that autoimmunity develops through successive stages across a variable period of time until the characteristic manifestations of disease are clinically apparent. Recent evidence indicates that the pre-clinical stages of autoimmune diseases involve a series of immunologic derangements and that this process is dynamic and progressive. During the years preceding clinical disease onset, there is progressive intensification in the humoral autoimmune response, characterized by increases in autoantibody titer, avidity, number of immunoglobulin isotypes, and spread of epitopes and of autoantigens targeted. This scenario is reminiscent of cancer processes that develop slowly by means of progressive stages, and may be interrupted by early detection and therapeutic intervention. Therefore, it might be reasoned that early intervention may be more effective in reverting the less firmly established autoimmune abnormalities at the pre-clinical stage of autoimmunity. With the continuous progress in novel immunologic therapeutic strategies, one can envision the possibility that early intervention at pre-clinical stages may lead to prevention of overt disease development and even cure of the autoimmune disorder.

Autoantibody epitope spreading in the pre-clinical phase predicts progression to rheumatoid arthritis

Rheumatoid arthritis (RA) is a prototypical autoimmune arthritis affecting nearly 1% of the world population and is a significant cause of worldwide disability. Though prior studies have demonstrated the appearance of RA-related autoantibodies years before the onset of clinical RA, the pattern of immunologic events preceding the development of RA remains unclear. To characterize the evolution of the autoantibody response in the preclinical phase of RA, we used a novel multiplex autoantigen array to evaluate development of the anti-citrullinated protein antibodies (ACPA) and to determine if epitope spread correlates with rise in serum cytokines and imminent onset of clinical RA. To do so, we utilized a cohort of 81 patients with clinical RA for whom stored serum was available from 1–12 years prior to disease onset. We evaluated the accumulation of ACPA subtypes over time and correlated this accumulation with elevations in serum cytokines. We then used logistic regression to identify a profile of biomarkers which predicts the imminent onset of clinical RA (defined as within 2 years of testing). We observed a time-dependent expansion of ACPA specificity with the number of ACPA subtypes. At the earliest timepoints, we found autoantibodies targeting several innate immune ligands including citrullinated histones, fibrinogen, and biglycan, thus providing insights into the earliest autoantigen targets and potential mechanisms underlying the onset and development of autoimmunity in RA. Additionally, expansion of the ACPA response strongly predicted elevations in many inflammatory cytokines including TNF-α, IL-6, IL-12p70, and IFN-γ. Thus, we observe that the preclinical phase of RA is characterized by an accumulation of multiple autoantibody specificities reflecting the process of epitope spread. Epitope expansion is closely correlated with the appearance of preclinical inflammation, and we identify a biomarker profile including autoantibodies and cytokines which predicts the imminent onset of clinical arthritis.

Ionic complex systems based on hyaluronic acid and PEGylated TNF-related apoptosis-inducing ligand for treatment of rheumatoid arthritis

The clinical applications of tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL), an emerging therapeutic protein for cancer and rheumatoid arthritis (RA), are limited by its instability and short biological half-life. In this study, efficient therapeutic modalities for RA treatment were developed in the form of nano-sized complexes (nanocomplexes) based on hyaluronic acid (HA) and polyethylene glycol (PEG)-derivatized TRAIL (PEG-TRAIL) formed by N-terminal specific PEGylation. The nanocomplexes were prepared by simply mixing the positively charged PEG-TRAIL and negatively charged HA, and showed negligible loss of bioactivity compared with the PEG-TRAIL. The in vivo biodistribution and diffusion kinetics of Cy5.5-labeled PEG-TRAIL in mice were observed using a near-infrared optical imaging system after subcutaneous injection of three different formulations: PEG-TRAIL in phosphate-buffered saline (PBS, pH 7.4), nanocomplex in PBS, or nanocomplex in 1% HA solution. The results suggested that PEG-TRAIL is released slowly in vivo from the nanocomplex in 1% HA. Experiments in a collagen-induced arthritis mouse model demonstrated that the magnitudes of therapeutic effects, as judged by clinical scores and histology, were significantly enhanced by the sustained delivery of PEG-TRAIL, with the order of nanocomplex in 1% HA>nanocomplex in PBS>PEG-TRAIL in PBS. In addition, sustained delivery of PEG-TRAIL from the nanocomplex in 1% HA resulted in significant reduction of serum inflammatory cytokines and collagen-specific antibodies that are responsible for the pathogenesis of RA. These results imply that HA/PEG-TRAIL nanocomplex formulations are promising therapeutic modalities for the treatment of RA.

Divergent effects of infliximab and anakinra therapies on macrophage phenotype from patients with refractory rheumatoid arthritis

Previously, we documented the co-expression of the inducible nitric oxide synthase (NOS2) and protein kinase C-eta (PKC-eta) in peripheral blood-derived macrophages (PBDM) from moderate to severe rheumatoid arthritis (RA) patients with elevated plasma nitric oxide levels but not from those with non-inflammatory osteoarthritis (OA) or normal plasma NO levels. The presence of PKC-eta was found to be required before macrophages could acquire the NOS2-positive phenotype and make copious levels of NO. In the current study, we report the divergent effects of two biological-based RA therapies which target TNFalpha function (infliximab) or IL1 response (anakinra) on the development of the NOS2-positive phenotype by PBDM in patients with refractory RA. Both infliximab and anakinra were effective in improving disease symptoms. However, treatment with anakinra, but not infliximab led to a complete suppression of NOS2 expression in PBDM and consequently, a more pronounced reduction in plasma NO levels. Data also revealed a requirement of both TNF-alpha and IL-1 in the development of the NOS2-positive macrophage phenotype. Finally, the data have shed light on the molecular mechanisms by which NO production may be regulated during disease progression to severe RA, and thus, offer a novel insight into the identification of future therapeutic targets for the treatment of inflammatory diseases.

B cell-targeted therapy for rheumatoid arthritis: an update on the evidence

Rheumatoid arthritis (RA) is a human systemic autoimmune disease with a prevalence of about 1%. Although an important role for B cells has been demonstrated in animal models of autoimmune, inflammatory arthritis, the importance of B cells in RA has been controversial for decades. The development of therapies targeting B cells may help to resolve this debate. Rituximab, a mouse-human chimeric monoclonal antibody against the B cell-specific antigen CD20, was the first B cell-targeted therapy tested in double-blind, placebo-controlled trials for RA. On the basis of the data from three separate trials, addition of rituximab to methotrexate appears to reduce significantly the signs and symptoms of rheumatoid factor-seropositive RA, as assessed by American College of Rheumatology (ACR) 20, 50 and 70 response criteria, and to be relatively safe. Significant questions about rituximab therapy still need to be addressed, including whether or not treatment with rituximab reduces radiographic progression of joint damage, the safety and efficacy of repeated courses of rituximab, and the long-term effects of rituximab on the immune system. Preliminary data on treatment of RA with belimumab, a fully human monoclonal antibody against B lymphocyte stimulator (a growth and survival factor for B cells) is now available. In a double-blind, placebo-controlled, phase II trial, belimumab was well tolerated and had a significant beneficial effect on the ACR 20 response. Thus, therapies specifically targeting B cells do appear to be effective in the treatment of RA, providing direct evidence that B cells are important in the pathogenesis of RA.

Interleukin-1 beta induction of matrix metalloproteinase-1 transcription in chondrocytes requires ERK-dependent activation of CCAAT enhancer-binding protein-beta

Interleukin-1 beta (IL-1beta) is a central mediator of inflammation and connective tissue destruction in rheumatoid arthritis. IL-1beta activates articular chondrocytes to produce matrix metalloproteinase-1 (MMP-1), an enzyme capable of dismantling the collagen scaffold of articular cartilage. To define the transcription factors and signaling intermediates that activate MMP-1 transcription in chondrocytes, we performed transient transfection of MMP-1 promoter constructs followed by reporter assays. These studies identified an IL-1beta-responsive region of the human MMP-1 promoter that contains a consensus CCAAT enhancer-binding protein (C/EBP) binding site. Deletion of this site reduced overall transcriptional activity of the MMP-1 promoter, as well as decreased fold induction by IL-1beta. IL-1beta stimulation of chondrocytes increased binding of C/EBP-beta to the MMP-1 C/EBP site. Extracellular signal regulated kinase (ERK) pathway-dependent phosphorylation of C/EBP-beta on threonine 235 activates this transcription factor. Here we show that IL-1beta stimulation of chondrocytes induced phosphorylation of C/EBP-beta on threonine 235, and that the ERK pathway inhibitor PD98059 reduced this phosphorylation. We further show that PD98059 reduces IL-1beta-induced MMP-1 mRNA expression in chondrocytes. Moreover, inhibition of the ERK pathway by expression of dominant-negative forms of ERK1 and ERK2 impaired the ability of IL-1beta to transactivate the MMP-1 promoter. Our findings demonstrate a novel role for C/EBP-beta in IL-1beta-induced connective tissue disease and define a new nuclear target for the ERK pathway in MMP-1 gene activation.

Effects of an acetone extract of Boswellia carterii Birdw. (Burseraceae) gum resin on adjuvant-induced arthritis in lewis rats

Ruxiang (Gummi olibanum), the dried gum resin of Boswellia carterii (BC), has been used in traditional Chinese medicine to alleviate pain and inflammation for thousands of years. In this random, blinded study, the anti-arthritic effects of a BC extract were observed and compared to vehicle control in a Lewis rat adjuvant arthritis model (n=8/group). Arthritis was induced by injecting CFA subcutaneously into the base of the tail, and the extract was administered orally (i.g.) for 10 consecutive days beginning on day 16 after the injection. Arthritic scores, paw edema, and the local tissue pro-inflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) were assessed. Toxicity and adverse effects of the extract were evaluated. At 0.90 g/kg per day, BC significantly decreased arthritic scores between days 20 and 25 (p<0.05) and reduced paw edema on days 18, 20 and 22 compared to control (p<0.05). It also significantly suppressed local tissue TNF-alpha and IL-1beta (p<0.05). No major adverse effects were observed in animals during the repeated-dose treatment profile although mild fur discoloration was noted. The data show that BC extract has significant anti-arthritic and anti-inflammation effects and suggest that these effects may be mediated via the suppression of pro-inflammatory cytokines.

Tracking of Proinflammatory Collagen-Specific T Cells in Early and Late Collagen-Induced Arthritis in Humanized Mice

Rheumatoid arthritis is a chronic inflammatory disease associated with certain HLA-DR4 subtypes. The target autoantigen(s) is unknown, but type II collagen (CII) is a candidate, with a single immunodominant DR4-restricted 261-273 T cell epitope (CII(261-273)). In the present study, we have prepared HLA-DR4:CII(261-273) tetramers and analyzed peripheral blood, lymph node, and synovial fluid cells from DR4-transgenic mice with early and late collagen-induced arthritis to draw a fuller picture of the role of CII-reactive Th cells in disease development. Their frequencies increased approximately 20-fold in blood 1-2 wk postimmunization, and even more in acutely arthritic joints. Our data strongly suggest that CII-specific Th cells are necessary, but not sufficient for collagen-induced arthritis. The CII-specific Th cells displayed an activated proinflammatory Th1 phenotype, and their expansion correlated with onset and severity of arthritis and also with anti-CII Ab levels. Surprisingly, shortly after the first clinical signs of arthritis, activated HLA-DR4:CII tetramer(+) cells became undetectable in the synovial fluid and rare in the blood, but persisted in lymph nodes. Consequently, future human studies should focus on patients with early arthritis, and on their synovial cells, to re-evaluate the occurrence and pathogenic importance of CII-specific or other Th cells in rheumatoid arthritis.

A therapeutic strategy uses histone deacetylase inhibitors to modulate the expression of genes involved in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by progressive destruction of the affected joints. The pathophysiology results from genetic susceptibility and autoimmune phenomena, leading to tissue inflammation and synovial hyperplasia termed pannus, which irreversibly destroys cartilage and bone. The current treatment options, which suppress immune responses or ameliorate inflammation, do not halt the destructive process. We found that the histone deacetylase (HDAC) inhibitors (phenylbutyrate and trichostatin A) causing histone hyperacetylation to modulate multiple gene expression not only induced the expression of p21(Cip1) and p16(INK4) in synovial cells but also inhibited the expression of tumor necrosis factor-alpha in affected tissues in adjuvant arthritis, an animal model of RA. Based on the observations that joint swelling is reduced, subintimal mononuclear cell infiltration is decreased, synovial hyperplasia is inhibited, pannus formation is suppressed, and no cartilage or bone destruction is seen, the HDAC inhibitors may represent a new class of compounds for the treatment of RA by simultaneously, coordinately, synergistically, or epigenetically modulating multiple molecular targets in the pathogenesis of RA.

Anticytokine therapy--new approach to the treatment of autoimmune and cytokine-disturbance diseases

We pioneered the theory (Nature, 1974) that hyperproduced interferons (cytokines) can bring autoimmune diseases (AD) and neutralizing these cytokines can be therapeutic. In 1975 we first performed successful anticytokine therapy using anti-IFN-alpha antibodies in patients with rheumatoid arthritis (RA). In 1989 we proposed also treating AD including AIDS by removing TNF-alpha and IFN-alpha. Our theory has been widely confirmed: injections of IFN-alpha and -gamma can exacerbate AD, while antibodies to IFN-alpha and -gamma and TNF-alpha can be therapeutic. Anti-IFN-gamma may be a universal treatment for Th1 AD. We had good results using anti-IFN-gamma to treat RA, multiple sclerosis (MS), transplant rejection, alopecia areata, vitiligo, psoriatic arthritis, psoriasis and others. For Th1/Th2 diseases, antagonists to cortisol could prevent the Th1-Th2 shift and allow treatment as a Th1 disease. Anticytokine therapy can also be therapeutic in many neuropsychiatric diseases. Every disturbance of homeostasis may lead to cytokine disturbance. IL-10 may restore homeostasis by inhibiting the production of certain Th1 cytokines and could be used to treat some embryonic disturbances and AD including MS.

Is insulin an antiinflammatory molecule?

I suggest that insulin suppresses the secretion and antagonizes the harmful effects of tumor necrosis factor-alpha, macrophage migration-inhibitory factor, and superoxide anion. Therefore, the glucose-insulin-potassium regimen might be beneficial in acute myocardial infarction and useful in the management of patients with septicemia, septic shock, and other inflammatory diseases in which tumor necrosis factor-alpha and macrophage migration-inhibitory factor have important roles.

Ex vivo gene transfer in the years to come

Synovial fibroblasts (SFs) have become a major target for ex vivo gene transfer in rheumatoid arthritis (RA), but efficient transduction of RA-SFs still is a major problem. The low proliferation rate and heterogeneity of RA-SFs, together with their lack of highly specific surface receptors, have hampered a more extensive application of this technique. Improving transduction protocols with conventional viral vectors, therefore, as well as developing novel strategies, such as alternative target cells, and novel delivery systems constitute a major challenge. Recent progress in this field will lead to the achievement of high transgene expression, and will facilitate the use of gene transfer in human trials.

Cross-talk between IL-1 and IL-6 signaling pathways in rheumatoid arthritis synovial fibroblasts

The balance between pro- and anti-inflammatory cytokines plays an important role in determining the severity of inflammation in rheumatoid arthritis (RA). Antagonism between opposing cytokines at the level of signal transduction plays an important role in many other systems. We have begun to explore the possible contribution of signal transduction cross-talk to cytokine balance in RA by examining the effects of IL-1, a proinflammatory cytokine, on the signaling and action of IL-6, a pleiotropic cytokine that has both pro- and anti-inflammatory actions, in RA synovial fibroblasts. Pretreatment with IL-1 suppressed Janus kinase-STAT signaling by IL-6, modified patterns of gene activation, and blocked IL-6 induction of tissue inhibitor of metalloproteases 1 expression. These results suggest that proinflammatory cytokines may contribute to pathogenesis by modulating or blocking signal transduction by pleiotropic or anti-inflammatory cytokines. The mechanism of inhibition did not require de novo gene activation and did not depend upon tyrosine phosphatase activity, but, instead, was dependent on the p38 stress kinase. These results identify a molecular basis for IL-1 and IL-6 cross-talk in RA synoviocytes and suggest that, in addition to levels of cytokine expression, modulation of signal transduction also plays a role in regulating cytokine balance in RA.

Randomized, double-blind trial of anti-interferon-gamma antibodies in rheumatoid arthritis

INTRODUCTION

An increasing body of evidence indicates that interferon (IFN )-gamma is an immunoregulator and may play a key role in the pathogenesis of autoimmune diseases, including rheumatoid arthritis (RA).

OBJECTIVE

To assess the efficacy and tolerability of anti-IFN-gamma in patients with active RA.

METHODS

In a randomized, double-blind trial, 30 patients with active RA were randomly assigned to receive intramuscular injections of anti-IFN-gamma, anti-TNF-alpha, or placebo for 5 consecutive days.

RESULTS

Both anti-cytokines were significantly superior to placebo. Patients stopping treatment due to lack of efficacy included I receiving anti-TNF-alpha, 2 receiving anti-IFN-gamma, and 9 receiving placebo. According to the physician's assessment, improvement was achieved by the 7th day in 9 patients receiving anti-TNF-alpha, 7 receiving anti-IFN-gamma, and 2 receiving placebo. By day 28 the corresponding figures were 8, 8, and 0, respectively.

CONCLUSION

Antibodies to IFN-gamma could be a promising approach to treating RA, especially its treatment-resistant forms.

Hypothesis: can glucose-insulin-potassium regimen in combination with polyunsaturated fatty acids suppress lupus and other inflammatory conditions?

In systemic lupus erythematosus, plasma concentrations of tumor necrosis factor alpha (TNF alpha) and other pro-inflammatory cytokines are elevated and those of transforming growth factor beta (TGF beta) are decreased. TNF alpha prevents lupus nephropathy whereas increased concentration of TGF beta causes glomerulosclerosis. Insulin inhibits TNF alpha and enhances TGF beta production, augments nitric oxide synthesis and blocks superoxide anion generation. Polyunsaturated fatty acids (PUFAs) also have actions similar to insulin. Hence, it is suggested that a combination of insulin (in the form of glucose-insulin-potassium) and PUFAs may be of benefit in lupus and other inflammatory conditions.

Pro- and Anti-inflammatory Cytokine Gene Expression in Rat Sciatic Nerve Chronic Constriction Injury Model of Neuropathic Pain

Cytokines may be pathophysiologically involved in hyperalgesia. Uncertainty exists about the types of cytokines and their site of action. To study the role of key pro- and anti-inflammatory cytokines in a chronic constriction model of neuropathic pain, mRNA expression of TNF, IL-1beta, IL-6, and IL-10 was quantified using competitive RT-PCR. Each cytokine mRNA in rat sciatic nerve was examined at days 3, 7, 14, and 45 after chronic constriction injury (CCI). We also undertook behavioral testing of these rats. Thermal warming and touch thresholds were significantly reduced at days 3, 7, and 14 in the CCI group, compared with the sham-operated group. Cytokine gene expression in sciatic nerve was significantly increased at day 7 for IL-1beta and IL-6 and at day 14 for TNF. Expression of IL-10 underwent a gradual and progressive increase, reaching statistical significance at day 45.

[Value of anti-TNF-alpha molecules in inflammatory and infectious diseases]

INTRODUCTION

The pathophysiological interest of tumor necrosis factor-alpha (TNF-alpha) has been recently reported in inflammatory and infectious diseases. Thus, TNF-alpha blockade has become a new field of therapeutical research.

CURRENT KNOWLEDGE AND KEY POINTS

Several biological agents specifically directed against TNF-alpha are available: anti-TNF-alpha monoclonal antibodies on the one hand--either mainly murine sequence (cA2), partially humanized (CDP 571) or fully human (D2E7)--and TNF-alpha soluble receptors on the other hand (lenercept or etanercept). The first clinical studies reveal interesting results. In rheumatoid arthritis (cA2, etanercept), these molecules may be used either alone or in synergistic combination with methotrexate. They produce a significant response compared to placebo or methotrexate alone, without loss of efficacy in medium-term treatment. In Crohn's disease (cA2 CDP571), they reduce significantly the activity of the disease, compared to placebo, and cA2 makes it possible to accelerate closure of the fistulas. The studies of severe sepsis did not reveal a significant efficacy, however, and only one study has been published on malignant disease, with a possible interesting effect. Even if these medications are usually well tolerated, the frequency of infections is slightly increased. The development of anti-DNA antibodies has also been reported, but drug-induced lupus is highly unusual.

FUTURE PROSPECTS AND PROJECTS

Further studies will define the place of anti-TNF-alpha biological agents among the other available treatments of rheumatoid arthritis and Crohn's disease. Because of their high cost, these drugs will probably be limited to patients with active inflammatory disease despite more conventional treatments.

The amino acid sequence of a monoclonal gamma 3-heavy chain from a patient with articular gamma-heavy chain deposition disease

Abnormal deposition of proteins, including monoclonal immunoglobulin gamma-heavy chains, may cause tissue damage and organ dysfunction. We here report the amino acid sequence of the free gamma-heavy chains present in serum and urine of the first reported case (patient G. L.) of synovial heavy chain deposition disease. The protein was heavily deleted and consisted of the hinge, in addition to the CH2 and CH3 domains, in a dimeric form, thus lacking its variable domain as well as the CH1 domain. The sequence was consistent with the gamma 3 subclass (gamma 3GL). Gm typing revealed the gamma 3 allotypes G3m(b0) and G3m(b1) in accordance with the residues Pro123, Phe128, Thr171 and Phe268 in gamma 3GL. Furthermore, the gamma 3GL molecule was glycosylated at Asn in position 129. Finally, the gamma 3GL protein was shown to contain a typical binding site for the first complement component, C1q, namely the residues Glu150, Lys152 and Lys154, with the potential of binding and activating complement, causing tissue damage following deposition.

NF-kappa B regulates VCAM-1 expression on fibroblast-like synoviocytes

Expression of VCAM-1 on synovial fibroblasts is a clinical hallmark of rheumatoid arthritis. The interaction of VCAM-1 and its integrin receptor very late Ag-4 is believed to be critically involved in the recruitment and retention of immune cells in the inflamed joints. To study the regulation of VCAM-1 in synovial fibroblasts, fibroblast-like synoviocytes (FLS) were isolated from the knee joints of normal mice and passaged repeatedly to obtain a homogeneous cell population. We have found that VCAM-1 is constitutively expressed on mouse FLS (mFLS) and that its surface expression is further increased after exposure to TNF-alpha. Nuclear translocation of transcription factor NF-kappa B including P50/P50 homodimer and P65/P50 heterodimer was activated by TNF-alpha treatment. In mFLS stably expressing a dominant-negative mutant of the inhibitory protein I-kappa B alpha- (mI-kappa B), which does not undergo proteolytic degradation, NF-kappa B remains in the cytosol and its activation in response to TNF-alpha is abolished. VCAM-1 protein expression after TNF-alpha stimulation was blocked in cells expressing the mI-kappa B. This effect is likely due to the loss of NF-kappa B-mediated transcription of VCAM-1, because the 5-fold increase in mRNA levels in response to TNF-alpha is absent in the mutant cells. To confirm these findings, we transduced mFLS with an adenoviral vector containing the mI-kappa B transgene. VCAM-1 expression was also blocked by mI-kappa B in this system, whereas cells transduced with a control adenoviral vector remained responsive to TNF-alpha. These results indicate that NF-kappa B mediates TNF-alpha-induced VCAM-1 expression on mFLS.

Is there a pathogenic link between gamma heavy chain disease and chronic arthritis?

In 1991, gamma heavy chain disease was diagnosed in a 43-year-old female, who 3 years earlier had contracted an erosive seronegative chronic arthropathy. In 1996, her lymphoproliferative disorder required treatment with melphalan and prednisolone. Laboratory studies revealed a gamma3 heavy chain monoclonal component in serum and urine. Massive localization of plasma cells and blasts with cytoplasmic or cell membrane staining for gamma3 chains, but no staining for light chains, was observed by immunohistochemical studies of bone marrow as well as affected synovial tissue. Large amounts of extracellular gamma3-chains were also deposited in the synovial membrane. This is the first documentation of gamma heavy chain deposition disease directly affecting articular structures. Whether it represents the primary pathogenic event followed by reactive inflammatory changes in the joints, or another example of gamma heavy chain disease preceded by chronic arthritis, remains elusive. Regardless, several common cellular and molecular mechanisms discussed here suggest a pathogenic link between the two disease processes.

PEGylated recombinant human soluble tumour necrosis factor receptor type I (r-Hu-sTNF-RI): novel high affinity TNF receptor designed for chronic inflammatory diseases

The proinflammatory cytokine, tumour necrosis factor alpha (TNFalpha) has been shown to play a pivotal part in mediating acute and chronic inflammation. The activities of TNFalpha are modulated by the proteolytic shedding of the soluble extracellular domains of the two TNF receptors, p55 sTNF-RI and p75 sTNF-RII. Amgen Inc has cloned and expressed a recombinant form of a natural inhibitor of TNFalpha, referred to as recombinant human soluble TNF receptor type I (r-Hu-sTNF-RI, sTNF-RI). sTNF-RI is an E coli recombinant, monomeric form of the soluble TNF-type I receptor. A high molecular weight polyethylene glycol (PEG) molecule is attached at the N-terminus position to form the molecule intended for clinical evaluations (PEG sTNF-RI). Preclinical studies to date demonstrate that PEG sTNF-RI is efficacious in rodent models of chronic inflammatory disease including rheumatoid arthritis and Crohn's disease at doses as low as 0.3 mg/kg given every other day. This dose results in plasma concentrations of 0.3 to 0.5 microg/ml. Higher doses with correspondingly higher plasma concentrations yield higher efficacy. It has also demonstrated efficacy in E coli lipopolysaccharide, and Staphylococcus enterotoxin B mediated models of acute inflammation in rodents and primates. Pharmacokinetic studies in mice, rats, cynomolgus monkeys, baboons, and chimpanzees have been conducted with PEG sTNF-RI. Absorption from a subcutaneous dose was slow, with the time to reach maximal plasma concentrations of 24-48 hours in rats, and in monkeys, and 3-29 hours in chimpanzees. The initial volume of distribution of PEG sTNF-RI was essentially equivalent to that of plasma (40 ml/kg). This suggests the protein does not appear to extensively distribute from the systemic circulation with a volume of distribution at steady state (Vss) less than 200 ml/kg in all species studied. These results are consistent with previous experience with PEGylated proteins in which PEGylation decreases both the rate of absorption and the plasma clearance of human recombinant proteins in animals and humans. The use of a PEG molecule will probably provide a more advantageous dosing schedule (that is, less frequent dosing) for the patient compared with a non-PEG sTNF-RI.

In vivo B1 kinin-receptor upregulation. Evidence for involvement of protein kinases and nuclear factor kappaB pathways

1. Intradermal (i.d.) injection of cytokines, IL-1beta and TNFalpha (5 ng, 60 and 30 min prior) produces a rapid onset up-regulation of des-Arg9-BK-mediated rat paw oedema. Here we analyse the mechanisms involved in des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta or TNFalpha. 2. Co-injection of anti-IL-1beta, anti-TNFalpha and anti-IL-8 (50 ng) significantly inhibited des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta (65, 37 and 42%) or TNFalpha (39, 64, 25%). IL-1 receptor antagonist (IRA, 100 microg) or IL-10 (10 ng) inhibited the oedema caused by des-Arg9-BK, in rats that had received either IL-1beta (67 and 63%) or TNFalpha (46 and 35%). 3. Co-injection of the PKC inhibitors, staurosporine (10 nmol) or RO 318220 (30 nmol) inhibited des-Arg9-BK-induced paw oedema (44 and 42% for IL-1beta and, 53 and 30% for TNFalpha, respectively). Genistein (tyrosine kinase inhibitor, 2.5 mg kg-1, s.c.) or PD 098059 (MAP-kinase inhibitor, 30 nmol) produced marked inhibition of des-Arg9-BK-induced oedema (58 and 39% for IL-1beta and 31 and 35% for TNFalpha respectively). 4. The NF-kappaB inhibitors TLCK (2 mg kg-1, i.p.) and PDCT (100 mg kg-1, i.p.) significantly inhibited the oedema of des-Arg9-BK in IL-1beta (27 and 83%) or TNFalpha (28 and 80%) pre-treated animals. 5. It is concluded that up-regulation of B1 receptors modulated by IL-1beta or TNFalpha involves the release of other cytokines, activation of PKC and tyrosine kinase pathways, co-ordinated with the activation of MAP-kinase and nuclear factor kappaB, reinforcing the view that B1 receptors may exert a pivotal role in modulating chronic inflammatory processes.

Immunopharmacology: anti-inflammatory therapy targeting transcription factors

Immunopharmacology is one of the most dynamic areas in pharmacology encompassing classical immunosuppressive drugs which reveal completely new clues concerning their mode of action as well as novel molecular biology approaches for treating inflammatory and autoimmune diseases, infections and cancer. This article focuses on transcription factors that regulate cell activities involved in immune and inflammatory cell responses and how traditional anti-inflammatory compounds such as glucocorticoids, cyclosporins, tacrolismus and salicylates interfere with the activation cascades triggering the transcription factors. Moreover, promising new initiatives for selective therapeutics including recombinant anti-inflammatory cytokines and proinflammatory cytokine antagonists, and gene therapy will be presented.

Etanercept: a review of its use in rheumatoid arthritis

Etanercept, a fusion protein consisting of the extracellular ligand-binding domain of the 75kD receptor for tumour necrosis factor-alpha and the constant portion of human IgG1, is administered by subcutaneous injection and is the first specific anti-cytokine therapy approved for rheumatoid arthritis. In patients with active rheumatoid arthritis [American College of Rheumatology (ACR) functional class I to III] who had failed to respond to previous treatment with > or = 1 disease-modifying antirheumatic drug (DMARD), etanercept, alone or in combination with methotrexate, produced improvements in all components included in the ACR core set of disease activity measures. A dose-response effect was apparent with etanercept 0.25 to 16 mg/m2 twice weekly in a randomised, double-blind study in 180 patients. The mean number of swollen or tender joints at the end of the 12-week study decreased by >50% in patients treated with etanercept 16 mg/m2 twice weekly and by <25% in patients treated with placebo. In a 24-week multicentre, randomised, double-blind study in 234 patients who were not allowed to use DMARDs, etanercept 10 or 25mg twice weekly had a rapid onset of effect. Significantly more patients treated with etanercept 25mg twice weekly than placebo experienced 20 (ACR 20), 50 (ACR 50) or 70% (ACR 70) improvement in ACR criteria after 3 and 6 months. Limited evidence suggests that the therapeutic effects of etanercept are maintained for up to 2 years. Etanercept 25mg twice weekly produced significant improvement in patients receiving oral or subcutaneous methotrexate 10 to 25 mg/week in a multicentre, randomised, double-blind, placebo-controlled study. A significantly greater proportion of patients treated with etanercept plus methotrexate (71%) than placebo plus methotrexate (27%) achieved the ACR 20 criteria after 6 months. Moreover, 39 and 15% of patients treated with etanercept plus methotrexate, but no placebo plus methotrexate recipients, had achieved the ACR 50 and ACR 70 criteria at this time. Etanercept 0.4 mg/kg twice weekly reduced disease activity in a preliminary, noncomparative study in 69 children aged > or =4 years with refractory juvenile rheumatoid arthritis. Although the overall frequency of infections was similar in patients treated with etanercept or placebo, upper respiratory tract infections were more common in patients treated with etanercept (29%) than placebo (16%). Injection site reactions occurred more frequently in etanercept- than placebo-treated patients, but did not bias the results of any study.

CONCLUSIONS

When etanercept is administered alone or in combination with methotrexate in patients with refractory rheumatoid arthritis, significant reductions in disease activity occur within 2 weeks and are sustained for at least 6 months. Thus, etanercept appears to be particularly well suited for use in patients who fail to respond to treatment with DMARDs.

Etanercept

Each month, subscribers to The Formulary® Monograph Service receive five to six researched monographs on drugs that are newly released or are in late Phase III trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. The monographs are published in printed form and on diskettes that allow customization. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board called The Formulary Information Exchange (The F.I.X). All topics pertinent to clinical pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The April 1999 Formulary monographs include cilostazol, altretinoin, rosiglitazone, oxcarbazepine, and rabeprazole. The DUE is on cilostazol.

Tumour necrosis factor alpha and mucocutaneous leishmaniasis

Allelic associations between polymorphisms at the tumour necrosis factor (TNF) locus within the major histocompatibility complex (MHC) and susceptibility to a range of autoimmune and infectious diseases have been established in humans. Among these is the severe and debilitating mucocutaneous form of leishmaniasis (MCL) caused by Leishmania braziliensis. This was preempted by the demonstration of high levels of circulating TNF-alpha in the sera of patients presenting with clinical mucocutaneous disease. Here, Jennie Blackwell looks at the implications this might have for the diagnosis and treatment of mucocutaneous disease, and the broader implications that the positive and negative immunomodulatory roles of TNF-alpha have in maintaining apparently detrimental alleles in the population.

Tumor necrosis factor alpha receptor I is important for survival from Streptococcus pneumoniae infections

Tumor necrosis factor alpha (TNF-alpha) is important in resistance to various microorganisms and provides signals to the target cells through two different receptors, TNF-alpha receptor I (TNFRI) (p55 receptor) and TNFRII (p75 receptor). To delineate the significance of the two different signaling pathways in resisting infections with extracellular bacteria, we examined the resistance of mice to Streptococcus pneumoniae (serotype 6B). TNF-alpha needs to be present early in infections, since one injection of wild-type mice with anti-TNF-alpha leads to an increased susceptibility of these mice to S. pneumoniae. TNF-alpha signaling through the p55 receptor (but not the p75 receptor) is crucial in resisting S. pneumoniae infections, because intraperitoneal injection of 100 CFU/mouse killed p55-deficient mice by day 2 of infection, whereas 1,000,000 CFU/mouse was needed to kill half of the control mice. p55-deficient mice do not show evidence of a deficient acute-phase response. All three types of mice (p55 deficient, p75 deficient, and normal) showed comparable rises in the levels of two acute-phase proteins (serum amyloid P and C3) at 24, 48, and 72 h after the experimental infections, and all of the mice showed comparable influxes of neutrophils to the site of infection. Finally, it was demonstrated that p55-deficient mice can be protected from the lethal effects of S. pneumoniae infection by injection of antibodies specific for S. pneumoniae polysaccharide capsule.

ABC50, a novel human ATP-binding cassette protein found in tumor necrosis factor-alpha-stimulated synoviocytes

We have used the recently developed technique of differential display polymerase chain reaction to seek for new genes modulated by tumor necrosis factor-alpha (TNF-alpha) in cultured synoviocytes. One PCR fragment was shown to correspond to a new gene that was mapped by high-resolution fluorescence in situ hybridization to band 6p21.33. The cDNA of this gene was cloned, and the deduced amino acid sequence revealed consensus motifs for the nucleotide binding folds of the ATP-binding cassette (ABC) family of proteins. However, a hydropathy curve showed that the polypeptide does not contain the transmembrane domains that are typical of the subfamily of ABC transporters and are associated with transporter/channel functions. The new gene, called ABC50, is the first human and mammalian ABC protein found to lack transmembrane domains. Homology with some yeast ABC proteins suggests that ABC50 codes for a new human ribosomal protein involved in translation of mRNA. It could therefore play a role in the enhancement of protein synthesis that follows TNF-alpha treatment of synoviocytes and thus participate in the inflammatory processes mediated by this cytokine. Furthermore, since TNF-alpha also modulates the expression of MHC class I genes, and these genes are known to map to 6p21.33, it is hypothesized that ABC50 and MHC class I are part of the same chromatin expression domain.

Therapeutic efficacy of multiple intravenous infusions of anti-tumor necrosis factor alpha monoclonal antibody combined with low-dose weekly methotrexate in rheumatoid arthritis

OBJECTIVE

To evaluate the efficacy, pharmacokinetics, immunogenicity, and safety of multiple infusions of a chimeric monoclonal anti-tumor necrosis factor alpha antibody (cA2) (infliximab; Remicade, Centocor, Malvern, PA) given alone or in combination with low-dose methotrexate (MTX) in rheumatoid arthritis (RA) patients.

METHODS

In a 26-week, double-blind, placebo-controlled, multicenter trial, 101 patients with active RA exhibiting an incomplete response or flare of disease activity while receiving low-dose MTX were randomized to 1 of 7 groups of 14-15 patients each. The patients received either intravenous cA2 at 1, 3, or 10 mg/kg, with or without MTX 7.5 mg/week, or intravenous placebo plus MTX 7.5 mg/week at weeks 0, 2, 6, 10, and 14 and were followed up through week 26.

RESULTS

Approximately 60% of patients receiving cA2 at 3 or 10 mg/kg with or without MTX achieved the 20% Paulus criteria for response to treatment, for a median duration of 10.4 to >18.1 weeks (P < 0.001 versus placebo). Patients receiving cA2 at 1 mg/kg without MTX became unresponsive to repeated infusions of cA2 (median duration 2.6 weeks; P=0.126 versus placebo). However, coadministration of cA2 at 1 mg/kg with MTX appeared to be synergistic, prolonging the duration of the 20% response in >60% of patients to a median of 16.5 weeks (P < 0.001 versus placebo; P=0.006 versus no MTX) and the 50% response to 12.2 weeks (P < 0.001 versus placebo; P=0.002 versus no MTX). Patients receiving placebo infusions plus suboptimal low-dose MTX continued to have active disease, with a Paulus response lasting a median of 0 weeks. A 70-90% reduction in the swollen joint count, tender joint count, and C-reactive protein level was maintained for the entire 26 weeks in patients receiving 10 mg/kg of cA2 with MTX. In general, treatment was well tolerated and stable blood levels of cA2 were achieved in all groups, except for the group receiving 1 mg/kg of cA2 alone, at which dosage antibodies to cA2 were observed in approximately 50% of the patients.

CONCLUSION

Multiple infusions of cA2 were effective and well tolerated, with the best results occurring at 3 and 10 mg/kg either alone or in combination with MTX in approximately 60% of patients with active RA despite therapy with low-dose MTX. When cA2 at 1 mg/kg was given with low-dose MTX, synergy was observed. The results of the trial provide a strategy for further evaluation of the efficacy and safety of longer-term treatment with cA2.

Anti-tumor necrosis factor-alpha monoclonal antibody therapy for rheumatoid arthritis

Because it plays a central role in the immunopathogenesis of rheumatoid arthritis (RA), TNF-alpha is an attractive target for immunomodulatory therapy. In a number of rigorous studies, monoclonal antibodies (mAb) specific for TNF-alpha have proved efficacious in patients with active RA. Data from these studies and issues related to mechanisms of action, potential toxicity, and future directions for this novel therapeutic approach are considered in this review.

Synovium as a source of increased amino-terminal parathyroid hormone-related protein expression in rheumatoid arthritis. A possible role for locally produced parathyroid hormone-related protein in the pathogenesis of rheumatoid arthritis

Proinflammatory cytokines, including tumor necrosis factor (TNF) and interleukin 1 (IL-1), mediate the joint destruction that characterizes rheumatoid arthritis (RA). Previous studies have shown that parathyroid hormone-related protein (PTHrP) is a member of the cascade of proinflammatory cytokines induced in parenchymal organs during lethal endotoxemia. To test the hypothesis that NH2-terminal PTHrP, a potent bone resorbing agent, could also be a member of the synovial cascade of tissue-destructive cytokines whose expression is induced in RA, PTHrP expression was examined in synovium and synoviocytes obtained from patients with RA and osteoarthritis (OA). PTHrP production, as determined by measurement of immunoreactive PTHrP(1-86) in tissue explant supernatants, was increased 10-fold in RA versus OA synovial tissue. Synovial lining cells and fibroblast-like cells within the pannus expressed both PTHrP and the PTH/PTHrP receptor, findings that were confirmed by in vitro studies of cultured synoviocytes. TNF-alpha and IL-1beta stimulated PTHrP expression in synoviocytes, while dexamethasone and interferon-gamma, agents with some therapeutic efficacy in the treatment of RA, inhibited PTHrP release. Treatment of synoviocytes with PTHrP(1-34) stimulated IL-6 secretion. These results suggest that proinflammatory cytokine-stimulated production of NH2-terminal PTHrP by synovial tissue directly invading cartilage and bone in RA may mediate joint destruction through direct effects on cartilage or bone, or, indirectly, via the induction of mediators of bone resorption in the tumor-like synovium.

PPAR-gamma agonists inhibit production of monocyte inflammatory cytokines

The peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a member of the nuclear receptor family of transcription factors, a large and diverse group of proteins that mediate ligand-dependent transcriptional activation and repression. Expression of PPAR-gamma is an early and pivotal event in the differentiation of adipocytes. Several agents that promote differentiation of fibroblast lines into adipocytes have been shown to be PPAR-gamma agonists, including several prostanoids, of which 15-deoxy-delta-prostaglandin J2 is the most potent, as well as members of a new class of oral antidiabetic agents, the thiazolidinediones, and a variety of non-steroidal anti-inflammatory drugs (NSAIDs). Here we show that PPAR-gamma agonists suppress monocyte elaboration of inflammatory cytokines at agonist concentrations similar to those found to be effective for the promotion of adipogenesis. Inhibition of cytokine production may help to explain the incremental therapeutic benefit of NSAIDs observed in the treatment of rheumatoid arthritis at plasma drug concentrations substantially higher than are required to inhibit prostaglandin G/H synthase (cyclooxygenase).

Taming TNF: strategies to restrain this proinflammatory cytokine

Recent studies have demonstrated the essential role of tumor necrosis factor alpha (TNF-alpha) in rheumatoid arthritis and Crohn's disease. This article discusses agents known to suppress the formation or activity of TNF-alpha, and summarizes clinical studies using anti-TNF-alpha antibodies.