Myonucleus-related properties in soleus muscle fibers of mdx mice

Distribution and total number of myonuclei in single soleus muscle fibers, sampled from tendon to tendon, were analyzed in mdx and wild-type (WT) mice. Apoptotic myonuclei and the microscopic structure around the myonuclei were also analyzed. Three types of muscle fibers of mdx mice with myonuclear distribution at either central, peripheral, or both central and peripheral regions were observed in the longitudinal analyses. All of the myonuclei were located at the peripheral region in WT mice. The total number of myonuclei counted in the whole length of fibers with peripheral myonuclei only was 17% less in mdx than in WT mice (p < 0.05). But the total myonuclear numbers in mdx mouse fibers with different distribution (peripheral vs. central) of myonuclei were identical, and the peripheral nucleus was noted where the central nucleus was missing. Myonuclei located between the center and peripheral regions were also seen in the cross-sectional analyses of muscle fibers. The cross-sectional area and length of fibers, sarcomere number, myonuclear size, myosin heavy chain expression, satellite cell number and neuromuscular junction were identical between each type of fiber. Apoptosis was not detected in any myonuclei located either in central or peripheral regions of muscle fibers. Thus, it was suggested that apoptosis-related loss of central myonuclei and regeneration-related new accretion at the peripheral region is not the cause of different distribution of myonuclei seen in muscle fibers in mdx mice. However, it was speculated that cross-sectional migration of myonuclei from central to peripheral regions may be induced in response to regeneration, because the total myonuclear numbers in fibers with different distribution of myonuclei were identical, and the peripheral nucleus was noted where the central nucleus was missing. Further, myonuclei located between the center and peripheral regions were also seen. However, the question remains as to how or why nuclei might migrate to the periphery in a regenerating muscle fiber, since there was no microscopic evidence of any structural changes around the myonuclei that may be responsible for the movement of the nucleus.

Progression of viraemia during treatment with infliximab in a patient with rheumatoid arthritis and chronic hepatitis C infection

Tumour necrosis factor α (TNFα) antagonists are effective for the treatment of rheumatoid arthritis (RA), but concerns remain about their safety in the presence of hepatitis C virus (HCV) infection. The influence of treatment with the TNFα antagonist infliximab on levels of HCV viraemia and serum transaminases in a 38-year-old patient with RA and HCV was examined to assess the safety of the drug. After starting infliximab treatment, the patient's clinical symptoms improved significantly (28-joint Disease Activity Score (DAS28) of less than 3) and levels of transaminases were normal. At the 14th injection of infliximab, the levels of HCV viraemia and transaminases were significantly elevated. After stopping the infliximab injections, the levels of transaminases returned to normal with infusion of glycyrrhizinate derivatives within 3 months. Evidence is provided of aggravation of serum transaminases and progression of viraemia during treatment with infliximab in a patient with RA and HCV infection.

Cytokine signal regulation and autoimmune disorders

Understanding of biological activities of cytokines and exquisite mechanism to regulate their functions has facilitated the therapeutic concept to restore the disequilibrium between pro-inflammatory cytokines and anti-inflammatory cytokines or cytokine inhibitors in some autoimmune inflammatory diseases such as rheumatoid arthritis (RA) and Crohn's disease. The application of molecular biology techniques to design monoclonal antibodies, soluble receptors, or receptor antagonists as therapeutic biologic agents made it possible to regulate the cytokine signals for the treatment of the diseases refractory to conventional therapies. Japanese researchers have contributed considerably to the establishment of cytokine signal regulation in autoimmune diseases. In this article, Japanese studies of cytokine signal regulation, particularly for Interleukin-6 (IL-6) in autoimmune diseases are reviewed.

Effect of interleukin-6 receptor blockage on renal injury in apolipoprotein E-deficient mice

Hyperlipidemia has been demonstrated to be associated with renal disease, yet the mechanism of renal injury is still poorly understood. Inflammation that occurs with the hyperlipidemia has been considered to play an important role in development of glomerular injury. In the present study, we investigated the role of interleukin-6 (IL-6), a key inflammatory molecule, on renal injury in apolipoprotein E-deficient (ApoE(-/-)) mice with severe hypercholesterolemia. The 6-wk-old mice were fed a high-fat diet and administered weekly rat anti-IL-6 receptor monoclonal antibody (MR16-1), control rat IgG, or saline for a total of 4 wk. We examined histopathological changes in the kidney and urinary excretion of protein and albumin. Saline- and IgG-treated mice showed remarkable proteinuria at 10 wk of age, whereas MR16-1-treated mice exhibited significantly lower levels. Renal histopathology of saline- and IgG-treated mice revealed striking lipid deposits and foam cells in the glomerular tuft, juxtaglomerular area, and arteriolar wall along with range of mesangial cell proliferation and matrix expansion. Notably, the severity of lipid deposits and mesangial cell proliferation were significantly reduced in MR16-1-treated mice. Immunohistochemistry demonstrated that mesangial IL-6 expression was dramatically reduced in MR16-1-treated mice compared with IgG-treated mice. Blocking the IL-6 receptor prevented progression of proteinuria and renal lipid deposit, as well as the mesangial cell proliferation associated with severe hyperlipoproteinemia. These results clearly demonstrate that IL-6 plays an essential role in the pathogenesis of hyperlipidemia-induced glomerular injury in ApoE(-/-) mice and suggests the usefulness of anti-IL-6 receptor antibody in treatments for hyperlipidemia-induced organ damage.

[IL-6 targeting therapy to retard structural joint damage in patients with rheumatoid arthritis]

Tocilizumab has been shown to have strong effect to retard the progression of structural joint damage in patients with rheumatoid arthritis. It was approved not only for signs and symptoms but also structural joint damage of rheumatoid arthritis in Japan. In this review, the efficacy, utility, positioning, and the future prospect will be discussed.

Interactions among type I and type II interferon, tumor necrosis factor, and beta-estradiol in the regulation of immune response-related gene expressions in systemic lupus erythematosus

INTRODUCTION

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by various clinical manifestations. Several cytokines interact and play pathological roles in SLE, although the etiopathology is still obscure. In the present study we investigated the network of immune response-related molecules expressed in the peripheral blood of SLE patients, and the effects of cytokine interactions on the regulation of these molecules.

METHODS

Gene expression profiles of peripheral blood from SLE patients and from healthy women were analyzed using DNA microarray analysis. Differentially expressed genes classified into the immune response category were selected and analyzed using bioinformatics tools. Since interactions among TNF, IFNgamma, beta-estradiol (E2), and IFNalpha may regulate the expression of interferon-inducible (IFI) genes, stimulating and co-stimulating experiments were carried out on peripheral blood mononuclear cells followed by analysis using quantitative RT-PCR.

RESULTS

Thirty-eight downregulated genes and 68 upregulated genes were identified in the functional category of immune response. Overexpressed IFI genes were confirmed in SLE patient peripheral bloods. Using network-based analysis on these genes, several networks including cytokines--such as TNF and IFNgamma--and E2 were constructed. TNF-regulated genes were dominant in these networks, but in vitro TNF stimulation on peripheral blood mononuclear cells showed no differences in the above gene expressions between SLE and healthy individuals. Co-stimulating with IFNalpha and one of TNF, IFNgamma, or E2 revealed that TNF has repressive effects while IFNgamma essentially has synergistic effects on IFI gene expressions in vitro. E2 showed variable effects on IFI gene expressions among three individuals.

CONCLUSIONS

TNF may repress the abnormal regulation by IFNalpha in SLE while IFNgamma may have a synergistic effect. Interactions between IFNalpha and one of TNF, IFNgamma, or E2 appear to be involved in the pathogenesis of SLE.

Long-term safety and efficacy of tocilizumab, an anti-IL-6 receptor monoclonal antibody, in monotherapy, in patients with rheumatoid arthritis (the STREAM study): evidence of safety and efficacy in a 5-year extension study

OBJECTIVES

To evaluate the safety and efficacy of 5-year, long-term tocilizumab monotherapy for patients with rheumatoid arthritis.

METHODS

In an open-label, long-term extension trial following an initial 3-month randomised phase II trial, 143 of the 163 patients who participated in the initial blinded study received tocilizumab monotherapy (8 mg/kg) every 4 weeks. Concomitant therapy with non-steroidal anti-inflammatory drugs and/or oral prednisolone (10 mg daily maximum) was permitted. All patients were evaluated with American College of Rheumatology (ACR) improvement criteria, disease activity score (DAS) in 28 joints, and the European League Against Rheumatism response, as well as for safety issues.

RESULTS

143 patients were enrolled in the open-label, long-term extension trial and 94 (66%) patients had completed 5 years as of March 2007. 32 patients (22%) withdrew from the study due to adverse events and one patient (0.7%) due to unsatisfactory response. 14 patients withdrew because of the patient's request or other reasons. The serious adverse event rate was 27.5 events per 100 patient-years, with 5.7 serious infections per 100 patient-years, based on a total tocilizumab exposure of 612 patient-years. Of the 88 patients receiving corticosteroids at baseline, 78 (88.6%) were able to decrease their corticosteroid dose and 28 (31.8%) discontinued corticosteroids. At 5 years, 79/94 (84.0%), 65/94 (69.1%) and 41/94 (43.6%) of the patients achieved ACR20, ACR50, and ACR70 improvement criteria, respectively. Remission defined as DAS28 less than 2.6 was achieved in 52/94 (55.3%) of the patients.

CONCLUSION

In this 5-year extension study, tocilizumab demonstrated sustained long-term efficacy and a generally good safety profile.

Study of active controlled tocilizumab monotherapy for rheumatoid arthritis patients with an inadequate response to methotrexate (SATORI): significant reduction in disease activity and serum vascular endothelial growth factor by IL-6 receptor inhibition therapy

We investigated the clinical efficacy and safety of tocilizumab (a humanized anti-IL-6 receptor antibody) monotherapy in active rheumatoid arthritis (RA) patients with an inadequate response to low dose methotrexate (MTX). In a multicenter, double-blind, randomized, controlled trial, 125 patients were allocated to receive either tocilizumab 8 mg/kg every 4 weeks plus MTX placebo (tocilizumab group) or tocilizumab placebo plus MTX 8 mg/week (control group) for 24 weeks. The clinical responses were measured using the American College of Rheumatology (ACR) criteria and the Disease Activity Score in 28 joints. Serum vascular endothelial growth factor (VEGF) levels were also monitored. At week 24, 25.0% in the control group and 80.3% in the tocilizumab group achieved ACR20 response. The tocilizumab group showed superior ACR response criteria over control at all time points. Additionally, serum VEGF levels were significantly decreased by tocilizumab treatment. The overall incidences of adverse events (AEs) were 72 and 92% (serious AEs: 4.7 and 6.6%; serious infections: 1.6 and 3.3%) in the control and the tocilizumab groups, respectively. All serious adverse events improved by adequate treatment. Tocilizumab monotherapy was well tolerated and provided an excellent clinical benefit in active RA patients with an inadequate response to low dose MTX.

Gene therapy for multiple myeloma

Prognosis of multiple myeloma (MM) remains insufficient despite the intervention of high dose chemotherapy with auto- or allo- hematopoietic stem cell transplantation and the advent of molecular target drugs such as thalidomide, lenalidomide, and bortezomib. Further development or new concepts of therapeutic approaches are still required for MM treatment. Current standard protocol for MM treatment does not include gene delivery method or oncolytic virus approaches. Since MM is a disorder originated from B cell lineage, it involves immunological aspects in both pathogenesis and clinical manifestations. Therefore, the comprehension of immunology as well as oncology is essential to exploit new therapeutic approaches. Recently, novel therapeutic concepts for MM have been emerging. In this review, we present current progress of gene therapy related to MM treatments as well as the overview of MM treatment history.

[Immunotherapy using IL-6 receptor as the target]

Monoclonal antibody-based therapy targeting interleukine-6 (IL-6) has been established as a treatment for autoimmune diseases, chronic inflammatory diseases, and lymphoproliferative disease. IL-6 is a multifunctional cytokine which plays pathological roles in Castleman's disease, rheumatoid arthritis, juvenile idiopathic arthritis, and Crohn's disease. Many groups have been exploring the therapeutic approach to block the IL-6 signal, and tocilizumab, a humanized monoclonal antibody against human IL-6 receptor, has been the most intensively studied agent for clinical use. A series of clinical trials of tocilizumab have demonstrated the robustness of safety and efficacy of tocilizumab in the treatment of patients with above diseases. In this review, targeting IL-6 actions as an immunotherapy is discussed.

A case report of a patient with refractory adult-onset Still's disease who was successfully treated with tocilizumab over 6 years

Interleukin-6 overproduction is pathologically involved in adult onset Still's disease (AOSD). We successfully treated a man with refractory AOSD utilizing tocilizumab. Tocilizumab was discontinued after 15 doses due to intestinal bleeding, but the efficacy was sustained over 21 months. Tocilizumab was readministered safely upon recurrence and showed similar efficacy over 6 years. Corticosteroid and NSAIDs could be discontinued and intestinal bleeding was no more observed. Tocilizumab can be a therapeutic option for AOSD.

Interleukin-6 in rheumatoid arthritis

PURPOSE OF REVIEW

Recent progress in cytokine studies has clarified the pathological roles played by cytokines and provided key evidence that antagonizing their actions can be therapeutic. The pathogenesis of rheumatoid arthritis, an autoimmune inflammatory disease, involves inflammatory cytokines such as tumour necrosis factor-alpha, interleukin-1 and interleukin-6. Anti-tumour necrosis factor-alpha and anti-interleukin-1 therapies have been used successfully to treat rheumatoid arthritis, but they are not consistently effective. We therefore need further therapies for this refractory disease. Interleukin-6 is another target molecule for blockade in the treatment of rheumatoid arthritis. Tocilizumab is a humanized antihuman interleukin-6 receptor monoclonal antibody designed to block the actions of interleukin-6. This review addresses the pathological significance of interleukin-6 and the current status of anti-interleukin-6 therapy for rheumatoid arthritis.

RECENT FINDINGS

The safety and efficacy of tocilizumab have been demonstrated in clinical trials conducted in patients with rheumatoid arthritis and other autoimmune inflammatory diseases, such as juvenile idiopathic arthritis and Crohn's disease.

SUMMARY

Clinical studies have demonstrated the pathological significance of interleukin-6 and the safety and efficacy of anti-interleukin-6 therapy with tocilizumab. Blockade of interleukin-6 - the second generation of anticytokine therapy - may be a promising treatment for rheumatoid arthritis.

Laboratory and febrile features after joint surgery in patients with rheumatoid arthritis treated with tocilizumab

OBJECTIVES

To understand the acute phase responses to surgical intervention in patients with rheumatoid arthritis (RA) treated with the anti-interleukin (IL)6 receptor antibody, tocilizumab.

METHODS

In a retrospective 1:1 pair-matched case-control study, 22 tocilizumab-treated RA cases and 22 cases treated with conventional disease-modifying antirheumatic drugs (DMARDs) and matched for type of surgery, age and sex were evaluated for body temperature every day, and blood C-reactive protein (CRP) levels and white blood cell (WBC), neutrophil and lymphocyte counts on days -1, 1, 3 and weeks 1 and 2 after joint surgery. Safety issues were also monitored.

RESULTS

No complications of infection or delay of wound healing occurred in either patient group. Tocilizumab partially, but significantly, suppressed the increase in body temperature on postoperative days 1 and 2, compared with DMARDs (average (SD) maximum increase in temperature was 0.45 (0.1) degrees C in the tocilizumab group and 0.78 (0.1) degrees C in the DMARD group; p<0.01). Tocilizumab completely suppressed the increase in CRP after surgery, whereas all cases treated with DMARDs showed a significant increase of CRP at postoperative day 1 (5.5 (0.6) mg/dl; p<0.001). WBC, neutrophil and lymphocyte counts showed no remarkable change after surgery, and there was no significant difference in any cell counts between the patient groups.

CONCLUSIONS

Within this small number of cases, safe operations on patients were performed during tocilizumab treatment. Tocilizumab suppressed fever and increase of CRP after surgery, whereas there was no influence on the transition in number of leukocytes. This characteristic postoperative response should be considered during tocilizumab treatment.

Successful treatment of a patient with Takayasu arteritis using a humanized anti-interleukin-6 receptor antibody

Takayasu arteritis (TA) is a chronic inflammatory disease that involves the aorta and its major branches. Since overproduction of interleukin-6 (IL-6) seems to play a pathogenic role in TA, we used the anti-IL-6 receptor (IL-6R) antibody tocilizumab to treat a 20-year-old woman with refractory active TA complicated by ulcerative colitis (UC). Treatment with tocilizumab improved the clinical manifestations of TA and the abnormal laboratory findings in this patient and ameliorated the activity of UC. These results indicate that IL-6R inhibition with tocilizumab might be a future treatment option for TA.

Abnormal expression of the genes involved in cytokine networks and mitochondrial function in systemic juvenile idiopathic arthritis identified by DNA microarray analysis

Objectives:

Systemic juvenile idiopathic arthritis (sJIA) is a rheumatic disease in childhood characterised by systemic symptoms and a relatively poor prognosis. Peripheral leukocytes are thought to play a pathological role in sJIA although the exact cause of the disease is still obscure. In this study, we aimed to clarify cellular functional abnormalities in sJIA.

Methods:

We analysed the gene expression profile in peripheral leukocytes from 51 patients with sJIA, 6 patients with polyarticular type JIA (polyJIA) and 8 healthy children utilising DNA microarrays. Gene ontology analysis and network analysis were performed on the genes differentially expressed in sJIA to clarify the cellular functional abnormalities.

Result:

A total of 3491 genes were differentially expressed in patients with sJIA compared to healthy individuals. They were functionally categorised mainly into a defence response group and a metabolism group according to gene ontology, suggesting the possible abnormalities in these functions. In the defence response group, molecules predominantly constituting interferon (IFN)γ and tumour necrosis factor (TNF) network cascades were upregulated. In the metabolism group, oxidative phosphorylation-related genes were downregulated, suggesting a mitochondrial disorder. Expression of mitochondrial DNA-encoded genes including cytochrome c oxidase subunit 1(MT-CO1) and MT-CO2 were suppressed in patients with sJIA but not in patients with polyJIA or healthy children. However, nuclear DNA-encoded cytochrome c oxidases were intact.

Conclusion:

Our findings suggest that sJIA is not only an immunological disease but also a metabolic disease involving mitochondria disorder.

Efficacy and safety of tocilizumab in patients with systemic-onset juvenile idiopathic arthritis: a randomised, double-blind, placebo-controlled, withdrawal phase III trial

BACKGROUND

Systemic-onset juvenile idiopathic arthritis does not always respond to available treatments, including antitumour necrosis factor agents. We investigated the efficacy and safety of tocilizumab, an anti-interleukin-6-receptor monoclonal antibody, in children with this disorder.

METHODS

56 children (aged 2-19 years) with disease refractory to conventional treatment were given three doses of tocilizumab 8 mg/kg every 2 weeks during a 6-week open-label lead-in phase. Patients achieving an American College of Rheumatology Pediatric (ACR Pedi) 30 response and a C-reactive protein concentration (CRP) of less than 5 mg/L were randomly assigned to receive placebo or to continue tocilizumab treatment for 12 weeks or until withdrawal for rescue medication in a double-blind phase. The primary endpoint of the double-blind phase was an ACR Pedi 30 response and CRP concentration of less than 15 mg/L. Patients responding to tocilizumab and needing further treatment were enrolled in an open-label extension phase for at least 48 weeks. The analysis was done by intention to treat. This study is registered with ClinicalTrials.gov, numbers NCT00144599 (for the open-label lead-in and double-blind phases) and NCT00144612 (for the open-label extension phase).

FINDINGS

At the end of the open-label lead-in phase, ACR Pedi 30, 50, and 70 responses were achieved by 51 (91%), 48 (86%), and 38 (68%) patients, respectively. 43 patients continued to the double-blind phase and were included in the efficacy analysis. Four (17%) of 23 patients in the placebo group maintained an ACR Pedi 30 response and a CRP concentration of less than 15 mg/L compared with 16 (80%) of 20 in the tocilizumab group (p<0.0001). By week 48 of the open-label extension phase, ACR Pedi 30, 50, and 70 responses were achieved by 47 (98%), 45 (94%), and 43 (90%) of 48 patients, respectively. Serious adverse events were anaphylactoid reaction, gastrointestinal haemorrhage, bronchitis, and gastroenteritis.

INTERPRETATION

Tocilizumab is effective in children with systemic-onset juvenile idiopathic arthritis. It might therefore be a suitable treatment in the control of this disorder, which has so far been difficult to manage.

Characteristics of fracture and related factors in patients with rheumatoid arthritis

To examine the clinical features of vertebral and non-vertebral fractures in patients with rheumatoid arthritis (RA), including insufficiency fractures, and to assess the risk factors for fracture, we prospectively studied 209 outpatients with rheumatoid arthritis for 1 year. The age, gender, Steinbrocker's functional class, glucocorticoid use, history of lower limb surgery, serum C-reactive protein (CRP), and use of bisphosphonates were evaluated. Examination for fractures was performed by radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scanning. Thirty-three fractures occurred in 24 patients over the 1-year study period, and the incidence was 15.8 fractures per 100 patient-years. Fractures occurred at various sites. The majority (70%) was insufficiency fracture, and more than 50% caused ambulatory dysfunction. Radiographic findings were absent in 39% of the fractures at the onset of pain. The functional class and glucocorticoid dose were significantly associated with fracture development. This prospective study showed that the incidence of fractures, especially insufficiency fractures, was very high in patients with rheumatoid arthritis and that most of their fractures caused gait disturbance. Early intervention to prevent secondary osteoporosis is recommended to maintain the quality of life in patients with rheumatoid arthritis, especially those with functional impairment or undergoing glucocorticoid therapy.

Humanized antihuman IL-6 receptor antibody, tocilizumab

Interleukin-6 (IL-6) is a pleiotropic cytokine that regulates immune responses and inflammatory reactions. Overproduction of IL-6 has been shown to play a role in inflammatory autoimmune diseases such as rheumatoid arthritis (RA), and juvenile idiopathic arthritis (JIA) and, therefore, an agent blocking IL-6 actions can be a therapy of these diseases. IL-6 belongs to a cytokine family, which shares the cytokine receptor subunit glycoprotein (gp) 130. This family also includes IL-11, oncostatin-M, and leukemia inhibitory factor (LIF). In the IL-6 receptor (IL-6R) system, both a membrane-bound IL-6R and a soluble form of IL-6R are able to mediate IL-6 signals into the cells through the interaction of gp130. Tocilizumab is a humanized antihuman IL-6 receptor antibody designed using genetic engineering technology. Tocilizumab recognizes both the membrane-bound and the soluble form IL-6R and specifically blocks IL-6 actions. Tocilizumab is expected to ameliorate the autoimmune inflammatory diseases with IL-6 overproduction and has been clinically developed as a therapeutic agent for RA, systemic-onset and articular types of JIA, Crohn's disease, etc. Tocilizumab has been shown to be effective not only for improving signs and symptoms but also for preventing joint destruction of RA. Immunopharmacology and clinical benefit of tocilizumab in RA is addressed.

Uneventful splenectomy and cholecystectomy in a patient treated with anti-interleukin-6 receptor antibody therapy

INTRODUCTION

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates various aspects of the immune responses, acute phase reactions, and hematopoiesis. In rodent models, IL-6 has been suggested to be one of the essential mediators for optimal acute phase responses to infection and tissue damage. However, in humans, the roles of IL-6 in acute phase responses after surgery remain poorly understood.

CASE REPORT

We present the first case report of successful splenectomy and cholecystectomy in a severe autoimmune-associated hemolytic anemia patient during treatment with a humanized anti-IL-6 receptor antibody.

DISCUSSION

This unique case suggests that IL-6 is not an essential cytokine to safely perform surgical intervention and to prevent postoperative complications and that surgical intervention may not be contraindicated but can be selected as a therapeutic modality in patients treated with anti-IL-6 receptor antibody therapy.

[Humanized anti-human IL-6 receptor antibody, tocilizumab]

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates immune response and inflammatory reaction. IL-6 has been shown to play pathological roles in the autoimmune reaction, inflammation, and joint destruction in rheumatoid arthritis, and, therefore, an agent blocking IL-6 actions can be a therapeutics of the disease. Tocilizumab is a humanized anti-human IL-6 receptor antibody designed using genetic engineering technology and the first therapeutic monoclonal antibody developed in Japan. Tocilizumab specifically blocks IL-6 actions and ameliorates the diseases with IL-6 overproduction. It has been clinically developed for rheumatoid arthritis and shown to be effective not only for improving signs and symptoms but also for preventing joint destruction of the disease. In this chapter, immunopharmacology and clinical utility of tocilizumab in rheumatoid arthritis is addressed.

A multicenter phase I/II trial of rituximab for refractory systemic lupus erythematosus

Although corticosteroids and immunosuppressants are widely used for the treatments of systemic lupus erythematosus (SLE), safer and more effective therapies are prerequisite. We and others have reported that anti-CD20 antibody rituximab targeting B cells are effective for refractory SLE and, therefore, safety and clinical efficacy of rituximab in SLE was evaluated by a multicenter phase I/II clinical trial. An open-label, multicenter study of 15 patients with active and refractory SLE (total British Isles Lupus Assessment Group [BILAG] score 8 to 17) was conducted. Rituximab was administered to 5 SLE patients as 4 infusions of 500 mg/body every week and to 10 SLE patients as 2 infusions of 1000 mg/body every other week. Assessment of safety, infusion reactions and adverse effects was used as the primary outcome for clinical tolerability and was evaluated by 28 weeks. Rituximab was well tolerated, with most experiencing no significant adverse effects. B cells rapidly reduced in all patients and remained low until 6 months post-treatment. Four patients developed human antichimeric antibodies without affecting efficacy of rituximab. Changes in routine safety laboratory tests clearly related to rituximab were not observed. Nine among 14 evaluable patients achieved the major or partial clinical response of BILAG score and prednisolone dose significantly decreased at the 28 weeks. Rituximab therapy appears to be safe for the treatment of active SLE patients and holds significant therapeutic promise, at least for the majority of patients experiencing profound B-cell depletion.

Local blockade of IL-6R signaling induces lung CD4+ T cell apoptosis in a murine model of asthma via regulatory T cells

We previously reported high levels of the soluble form of the IL-6R (sIL-6R) in the airways of asthmatic subjects. Here, we analyzed the IL-6R effects on Th2 cell survival in the lung by locally antagonizing sIL-6R-mediated trans-signaling with a designer fusion protein (gp130-Fc) as well as IL-6R signaling with an antibody against the gp80 unit of the IL-6R (alphaIL-6R) in a murine model of asthma after ovalbumin peptide (OVA) sensitization and challenge. Blockade of the sIL-6R led to a significant decrease in inflammatory cells by an apoptosis-independent mechanism. In contrast, local treatment with alphaIL-6R antibodies that also block signaling via the membrane-bound IL-6R (mIL-6R) led to decreased signal transducers and activators of transcription (STAT)-3 but not STAT-1 phosphorylation in the lung of treated mice as compared with control-treated mice. Moreover, this treatment induced apoptosis of the cells present in the airways of OVA-treated mice as well as apoptosis of lung CD4+ effector T cells. Subsequent studies showed that this effect was mediated by lung CD4+CD25+Foxp3+ T regulatory cells by a cell-cell interaction, thereby contributing to the resolution of airway hyperresponsiveness in OVA-treated mice given anti-IL-6R antibodies. Taken together, these data suggest that blockade of mIL-6R signaling leads to cell death of lung effector T cells by activating regulatory T cells in experimental asthma. Local targeting of IL-6R signaling could be a novel approach for inducing Th2 T cell death in allergic airways via regulatory T cells.

Study of active controlled monotherapy used for rheumatoid arthritis, an IL-6 inhibitor (SAMURAI): evidence of clinical and radiographic benefit from an x ray reader-blinded randomised controlled trial of tocilizumab

OBJECTIVE

To evaluate the ability of tocilizumab (a humanised anti-IL-6 receptor antibody) monotherapy to inhibit progression of structural joint damage in patients with RA.

METHODS

In a multi-centre, x ray reader-blinded, randomised, controlled trial, 306 patients with active RA of <5 years' duration were allocated to receive either tocilizumab monotherapy at 8 mg/kg intravenously every 4 weeks or conventional disease-modifying antirheumatic drugs (DMARDs) for 52 weeks. Radiographs of hands and forefeet were scored by the van der Heijde modified Sharp method.

RESULTS

Patients had a mean disease duration of 2.3 years and a disease activity score in 28 joints of 6.5 at baseline. Mean total modified Sharp score (TSS) was 29.4, which was very high despite the relatively short disease duration. At week 52, the tocilizumab group showed statistically significantly less radiographic change in TSS (mean 2.3; 95% CI 1.5 to 3.2) than the DMARD group (mean 6.1; 95% CI 4.2 to 8.0; p<0.01). Tocilizumab monotherapy also improved signs and symptoms. The overall incidences of AEs were 89% and 82% (serious AEs: 18% and 13%; serious infections: 7.6% and 4.1%) in the tocilizumab and DMARD groups, respectively.

CONCLUSION

Tocilizumab monotherapy was generally well tolerated and provided radiographic benefit in patients with RA.

[Clinical benefits of anti-human IL-6 receptor antibody therapy]

Interleukin-6 (IL-6) plays pathological roles in promoting autoimmune reactions and chronic inflammation as well as destruction of bone and cartilage in rheumatoid arthritis (RA). Humanized anti-human IL-6 receptor antibody, tocilizumab, specifically recognizes human IL-6 receptor and inhibits IL-6 actions. Tocilizumab has been shown to ameliorate the disease activity of RA in the clinical trials. Tocilizuamb can be a new therapy based on the pathology of RA.

Establishment of a new interleukin-6 (IL-6) receptor inhibitor applicable to the gene therapy for IL-6-dependent tumor

Interleukin-6 (IL-6) is a key molecule involved in the pathogenesis of several inflammatory diseases and malignancies. Treatments that inhibit IL-6 mitigate the clinical conditions of such diseases. Here, we report on the development of a new receptor inhibitor of IL-6 (NRI) by genetically engineering tocilizumab, a humanized anti-IL-6 receptor monoclonal antibody which specifically blocks IL-6 signaling. This NRI consists of VH and VL of tocilizumab in a single-chain fragment format dimerized by fusing to the Fc portion of human immunoglobulin G(1). The binding activity to IL-6 receptor and the biological activity of the purified NRI were found to be similar to those of parental tocilizumab. Because NRI is encoded on a single gene, it is easily applicable to a gene delivery system using virus vehicles. We administered an adenovirus vector encoding NRI to mouse i.p. and monitored the serum NRI level and growth reduction property on S6B45, an IL-6-dependent multiple myeloma cell line, in vivo. Adequate amount of the serum NRI level to exert anti-IL-6 action could be obtained by the NRI gene introduction combined with adenovirus gene delivery, and this treatment inhibited the in vivo S6B45 cell growth significantly. These findings indicate that NRI is a promising agent applicable to the therapeutic gene delivery approach for IL-6-driven diseases.

Anti-interleukin-6 receptor antibody therapy in rheumatic diseases

In the treatment of rheumatic diseases such as rheumatoid arthritis (RA) or systemic onset juvenile idiopathic arthritis (soJIA), new therapies targeting pro-inflammatory cytokines have been developed. IL-6 is a pleiotropic cytokine with a wide range of biological activities including a pro-inflammatory mediator activity. Overproduction of IL-6 has been reported to be pathologically involved in the rheumatic diseases and, therefore, blockade of IL-6 actions may improve the disease. Tocilizumab, a humanized monoclonal antibody against human interleukin-6 receptor (IL-6R), inhibits IL-6 binding to IL-6R and specifically interferes with IL-6 actions. Castleman's disease is an atypical lymphoproliferative disorder caused by the overproduction of IL-6. Tocilizumab therapy improves immunological and hematological abnormalities as well as systemic inflammatory symptoms including wasting. This translational study also confirmed the pathological significance of IL-6 in the disease. RA is a representative autoimmune inflammatory disease characterized by bone and cartilage destruction in multiple joints. Since IL-6 also plays pathological roles in RA, tocilizumab therapy has been introduced to the patients with refractory disease and has shown a strong therapeutic effect. Besides Castleman's disease and RA, tocilizumab has been shown to be effective for patients with soJIA and Crohn's disease. Tocilizumab treatment is generally well tolerated and safe. Therefore, tocilizumab can be a promising therapeutic agent for the rheumatic diseases in which IL-6 overproduction is pathologically involved.

Interleukin 6: from bench to bedside

Interleukin (IL)-6 is a pleiotropic cytokine that has important roles in the regulation of the immune response, inflammation, and hematopoiesis. Disruption of IL-6 regulation might, however, affect the immune response and consequently induce immune-mediated inflammatory diseases such as rheumatoid arthritis, systemic juvenile idiopathic arthritis, Castleman disease, and Crohn's disease. Overproduction of IL-6 also contributes, through its roles as a growth factor or an antiapoptotic factor, to the development of malignant diseases such as multiple myeloma and renal cancer. Progress in the study of IL-6 has increased our understanding of the pathological roles of this cytokine in these diseases and provided key evidence that antagonizing its activities can be used as a therapeutic strategy. The application of molecular biology techniques to design monoclonal antibodies as therapeutic agents has made it possible to regulate the IL-6 signal to successfully treat diseases that have so far proved refractory to conventional therapies. Blocking IL-6 actions by use of a humanized antibody, tocilizumab, which targets the IL-6 receptor, has been proven to be therapeutically effective for rheumatoid arthritis, systemic juvenile idiopathic arthritis, Castleman disease and Crohn's disease. In this review, we discuss a paradigm of IL-6 from basic science to clinical use.

Suppressor of cytokine signaling-1 expression by infectivity-enhanced adenoviral vector inhibits IL-6-dependent proliferation of multiple myeloma cells

Multiple myeloma (MM) accounts for 10% of hematological malignant disorders. Its refractory nature indicates the necessity of developing novel therapeutic modalities. Since interleukin 6 (IL-6) is one of the major growth factors for MM cells, we expressed suppressor of cytokine signaling-1 (SOCS-1), one of the blockades of IL-6 receptor downstream signaling, to suppress the proliferation of MM cells. Because MM cells are resistant to conventional adenoviral vector infection, we utilized infectivity-enhanced adenoviral vectors with an RGD4C motif in the adenoviral fiber-knob region (RGD-modified vector). In infectivity analysis, RGD-modified vectors were superior to unmodified controls in the majority of the MM cell lines tested. The overexpression of SOCS-1 using infectivity-enhanced adenoviral vectors achieved growth suppression in IL-6-dependent MM cells, but not in the IL-6-independent cells. IL-6-induced STAT3 phosphorylation was suppressed in IL-6-dependent cells, indicating that the signal transduction cascade of the IL-6 receptor signaling was blocked. In aggregate, SOCS-1 overexpression with RGD-modified adenoviral vectors achieved the antiproliferative effect in IL-6-dependent MM cells. These results provide an initial proof-of-principle of the anticancer effect of SOCS-1 expression vector as well as a promise for the future development of therapeutic modality for MM based on this vector.

Interleukin-6 induces both cell growth and VEGF production in malignant mesotheliomas

Malignant mesothelioma (MM), an incurable tumor, is reportedly an interleukin-6 (IL-6) secreting tumor. The pathological significance of IL-6 overexpression in this tumor, however, has remained unclear. We investigated the biological functions of IL-6 in mesotheliomas. Five mesothelioma cell lines were analyzed for IL-6 production and IL-6 receptor (IL-6R) expression. Of them, 2 produced high levels of IL-6, 2 produced intermediate levels and 1 cell line showed no secretion. All mesothelioma cell lines used in this study expressed very small amounts of IL-6R mRNA. We compensated for this low level of IL-6R expression in mesotheliomas by adding recombinant soluble IL-6R (sIL-6R) to mediate the IL-6 signal. IL-6 together with sIL-6R was found to promote cell growth of H2052 and H226 MMs classified as high-level IL-6 producers in a dose-dependent manner. Moreover, a humanized anti-IL-6R antibody (MRA) capable of blocking IL-6 signaling suppressed the cell growth of mesotheliomas induced by IL-6/sIL-6R. These findings demonstrate that IL-6 serves as an autocrine growth factor in the development of mesothelioma. In addition, IL-6/sIL-6R stimulation increased the expression of vascular endothelial growth factor (VEGF) in 4 out of 5 cell lines, and this induction was inhibited by MRA treatment. The involvement of the signal transducer and activator of transcription 3 (STAT3) pathway in both cell growth and VEGF induction by IL-6/sIL-6R was verified by dominant negative STAT3 transduction combined with adenovirus gene-delivery methods. Although IL-6 induces VEGF through the JAK2/STAT3 pathway, anti-VEGF antibody could not inhibit the IL-6-induced cell growth observed in H2052 and H226. We concluded that IL-6-dependent growth does not occur via VEGF induction. These results suggest that treatment with anti-IL-6R antibody may constitute a potential molecular targeting therapy for MMs.

Anti-interleukin-6 receptor antibody therapy -From Bedside to Bench-

Recent progress in immunology, utilizing molecular biology techniques, has elucidated the molecular mechanism of immune system. In the treatment of autoimmune diseases, molecular targeting therapies utilizing biologics such as monoclonal antibodies are now available. However, exact causes of the most autoimmune diseases are not known and there remain many issues which should be resolved. Interleukin-6 (IL-6) is a cytokine which regulates immune response and inflammation. Deregulated overproduction of IL-6 is involved in the immune-inflammatory diseases such as Castleman's disease and rheumatoid arthritis. A humanized anti-IL-6 receptor antibody tocilizumab has been proven to be therapeutically effective for the diseases. Simultaneously, we have learned new biological activities from the translational research. In this review, a study from bedside to bench is to be discussed.

Anti–interleukin-6 receptor antibody therapy favors adrenal androgen secretion in patients with rheumatoid arthritis: A randomized, double-blind, placebo-controlled study

OBJECTIVE

Proinflammatory cytokines such as tumor necrosis factor (TNF) were demonstrated to inhibit adrenal steroidogenesis in patients with rheumatoid arthritis (RA), and this was particularly evident in the increase in adrenal androgen levels during anti-TNF therapy. This study investigated the influence on steroidogenesis of an interleukin-6 (IL-6)-neutralizing strategy using IL-6 receptor monoclonal antibodies (referred to as MRA).

METHODS

In a placebo-controlled, double-blind, randomized study over 12 weeks in 29 patients with RA being treated with prednisolone, 13 of whom received placebo and 16 of whom received 8 mg MRA/kg body weight, the effects of MRA on serum levels of adrenocorticotropic hormone (ACTH), cortisol, 17-hydroxyprogesterone (17OHP), dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), androstenedione (ASD), estrone, and 17beta-estradiol, as well as their respective molar ratios, were determined.

RESULTS

MRA therapy markedly improved clinical signs of inflammation (the erythrocyte sedimentation rate, swollen joint score, and Disease Activity Score in 28 joints). Serum levels of ACTH and cortisol and the molar ratio of cortisol to ACTH did not change. Although serum levels of DHEA and DHEAS remained stable during therapy, the DHEAS:DHEA molar ratio significantly decreased in treated patients (P = 0.048). Serum levels of ASD as well as the ASD:cortisol and ASD:17OHP molar ratios increased in MRA-treated patients (minimum P < 0.004). Serum levels of estrone and 17beta-estradiol did not change. but the estrone:ASD molar ratio (an indicator of aromatization) decreased during 12 weeks of MRA treatment (P = 0.001).

CONCLUSION

Neutralization of IL-6 increases secretion of biologically active adrenal androgens in relation to that of precursor hormones and estrogens. This is another important indication that proinflammatory cytokines interfere with adrenal androgen steroidogenesis in patients with RA.

The therapy of autoimmune diseases by anti-interleukin-6 receptor antibody

Interleukin (IL)-6 plays essential roles not only in the immune response, but also in haematopoiesis and the central nervous system. Deregulated production of IL-6 has been found in chronic inflammatory autoimmune diseases, such as rheumatoid arthritis (RA), systemic onset juvenile idiopathic arthritis (soJIA), Crohn's disease (CD) and systemic lupus erythematosus (SLE). Furthermore, IL-6 activities can explain many symptoms of these diseases. More importantly, serum levels of IL-6 are correlated with disease activity. Based on these facts, the authors planned to develop a humanized anti-IL-6 receptor antibody, tocilizumab (previously known as MRA), as a therapeutic agent for these inflammatory autoimmune diseases. Tocilizumab is a neutralising antibody to suppress IL-6 signalling mediated by both membranous and soluble IL-6R. Clinical efficacy of tocilizumab in RA, soJIA, adult-onset Still's disease or CD patients has been discussed in this review. In all of these diseases, tocilizumab has improved the disease activity, suggesting that IL-6 plays an essential role in the pathogenesis of these diseases.

Humanized anti-interleukin-6 receptor antibody treatment of multicentric Castleman disease

Multicentric Castleman disease (MCD) is an atypical lymphoproliferative disorder characterized by systemic lymphadenopathy and constitutional inflammatory symptoms. Dysregulated overproduction of interleukin-6 is responsible for the clinical abnormalities. This multicenter prospective study was undertaken to evaluate the safety and efficacy of a humanized anti-human interleukin-6 (IL-6) receptor monoclonal antibody (MRA) in patients with MCD. We report here results of the first 60 weeks of the study enrolling 28 patients. The initial dosing period consisted of 8 infusions of 8 mg/kg MRA administered biweekly. Adjustments in the dose and treatment interval were allowed for each patient in an extension phase after 16 weeks. Within 16 weeks, treatment with MRA consistently alleviated lymphadenopathy and all the inflammatory parameters. Hemoglobin, albumin, and total cholesterol levels, high-density lipoprotein cholesterol values, and body mass index all increased significantly. In addition, fatigue diminished. Chronic inflammatory symptoms were successfully managed over 60 weeks. In 8 (28.6%) patients, the MRA dose was decreased or the treatment interval was extended without exacerbation. Eleven (73.3%) of 15 patients who had received oral corticosteroids before study entry were able to do well on a reduced corticosteroid dose. Most adverse events were mild to moderate in severity. MRA was tolerated well and significantly alleviated chronic inflammatory symptoms and wasting in patients with MCD.

Imaging of lesions in a murine rheumatoid arthritis model with a humanized anti-interleukin-6 receptor antibody

Rheumatoid arthritis (RA) has been attributed to the abnormal production of cytokine interleukin-6 (IL-6), which has a variety of physiological activities. In vivo IL-6-receptor imaging provides useful suggestions regarding the mechanism of anti-IL-6-receptor antibody action and indicates a basic therapeutic strategy for treating RA. Therefore, this study was designed to establish a method for radiolabeling anti-IL-6-receptor antibodies and to investigate the feasibility of using radiolabeled anti-IL-6-receptor antibodies in the scintigraphic imaging of lesions in an animal RA model. Anti-IL-6-receptor antibodies were conjugated with a bifunctional chelating agent, hydrazinonicotinamide (HYNIC), and radiolabeled with technetium-99m (99mTc) using the ligand exchange reaction of 99mTc-tricine complex. The binding affinity was estimated using the U266 cell line. Whole body scintigraphy, biodistribution and autoradiography were undertaken in mice containing synovial cells that had been transplanted from an RA patient. Our findings showed that the antibodies accumulated in the implanted tissue. When radiolabeled anti-IL-6-receptor antibodies are used in scintigraphic imaging, the distribution of the IL-6-receptors is associated with the inflammatory cell infiltration that is seen in the early stage of RA. Accordingly, imaging with humanized anti-IL-6-receptor antibodies appears to be useful for detecting early pathophysiological conditions and assessing the efficacy of antibody treatment as well as the prognosis of patients with RA.

All-trans-retinoic acid inhibits the development of mesangial proliferative glomerulonephritis in interleukin-6 transgenic mice

All-trans-retinoic acid (ATRA), a vitamin A derivative, was reported to suppress the interleukin-6 (IL-6) production and to downregulate the IL-6 receptor (IL-6R) and/or its signal transducer glycoprotein 130. We investigated the in vivo antinephritic effect of ATRA on IL-6 transgenic mice which had developed mesangial proliferative glomerulonephritis (PGN) as well as its in vitro inhibitory effect on the proliferation of rat mesangial cells. In vivo experiments on IL-6 transgenic mice showed that ATRA administration suppressed proteinuria and hematuria and reduced the IL-6 concentrations; furthermore, histological examination demonstrated that it improved PGN. In vitro experiments using rat mesangial cells demonstrated that ATRA inhibited cell growth in a dose-dependent manner within a range from 10(-4) to 10(-6) M. This inhibition by ATRA was partially counteracted by the addition of IL-6. RT-PCR assay results showed that ATRA also reduced IL-6R, but not the glycoprotein 130 expression in mesangial cells. These findings indicate that, by blocking of the IL-6 function, ATRA may be therapeutically effective in PGN.

Optimization of the drug solution preparation process for a production-scale crossflow ultrafiltration system

This article describes a new approach to optimizing the drug solution preparation process for a production-scale crossflow ultrafiltration system. Equations were proposed to predict the concentration of the active ingredient and the volume of drug solution in the crossflow ultrafiltration process. These equations take into account the residual water remaining in the process line after the set-up of the ultrafiltration system, the residual drug solution remaining in the process line after ultrafiltration, and the residual Water for Injection (WFI) remaining in the process line after WFI rinsing. Because the residual water or residual drug solution varies slightly for each type of production, it was convenient to define them as preparation parameters. Using the proposed equations, testing was performed during early production in order to collect data on the crossflow ultrafiltration process, and the preparation parameters were then optimized. The concentration of the active ingredient and the weight of the drug solution (which was converted to the drug solution volume using its specific gravity) were calculated accurately with the optimized preparation parameter using the proposed equations. These results indicate that the proposed equations and method of establishing the preparation parameters are useful for a production-scale crossflow ultrafiltration system.

The IL-6R alpha chain controls lung CD4+CD25+ Treg development and function during allergic airway inflammation in vivo

The cytokine IL-6 acts via a specific receptor complex that consists of the membrane-bound IL-6 receptor (mIL-6R) or the soluble IL-6 receptor (sIL-6R) and glycoprotein 130 (gp130). In this study, we investigated the role of IL-6R components in asthma. We observed increased levels of sIL-6R in the airways of patients with allergic asthma as compared to those in controls. In addition, local blockade of the sIL-6R in a murine model of late-phase asthma after OVA sensitization by gp130-fraction constant led to suppression of Th2 cells in the lung. By contrast, blockade of mIL-6R induced local expansion of Foxp3-positive CD4+CD25+ Tregs with increased immunosuppressive capacities. CD4+CD25+ but not CD4+CD25- lung T cells selectively expressed the IL-6R alpha chain and showed IL-6-dependent STAT-3 phosphorylation. Finally, in an in vivo transfer model of asthma in immunodeficient Rag1 mice, CD4+CD25+ T cells isolated from anti-IL-6R antibody-treated mice exhibited marked immunosuppressive and antiinflammatory functions. IL-6 signaling therefore controls the balance between effector cells and Tregs in the lung by means of different receptor components. Furthermore, inhibition of IL-6 signaling emerges as a novel molecular approach for the treatment of allergic asthma.

Clinical Studies in Patients With Castleman's Disease, Crohn's Disease, and Rheumatoid Arthritis in Japan

Interleukin (IL)-6 is a pleiotropic cytokine with a wide range of biological activities and regulates immunological reactions, inflammatory responses, and hematopoiesis. Overproduction of IL-6 has been shown to be pathologically involved in some inflammatory diseases, such as Castleman's disease, Crohn's disease, and rheumatoid arthritis. Clinical studies have been conducted to investigate a role of IL-6 and the therapeutic potential of anti-IL-6 therapy for these diseases using humanized anti-IL-6 receptor antibody (tocilizumab; currently known as MRA). Overall, tocilizumab was well-tolerated, and improvements of signs and symptoms were observed, confirming the pathological role of IL-6 and suggesting that the blockade of IL-6 could become a new and important treatment option in these refractory diseases.