Selective Costimulation Modulators

EGF-Receptor against Amphiregulin (AREG) Influences Costimulatory Molecules on Monocytes and T Cells and Modulates T-Cell Responses

Amphiregulin (AREG) is a ligand of the epidermal growth factor receptor (EGFR) and has been shown to regulate the phagocytosis-induced cell death of monocytes in peripheral blood. AREG-dependent apoptotic signaling engages factors of the intrinsic and extrinsic apoptotic pathway, such as BCL-2, BCL-XL, and death ligand/receptor CD95/CD95L. Here, we tested the hypothesis that AREG influences costimulatory monocyte functions, which are crucial for T-cell responses. We found a stronger expression of AREG and EGFR in monocytes compared to lymphocytes. As a novel function of AREG, we observed reduced T-cell proliferation following polyclonal T-cell stimulation with OKT3. This reduction of proliferation occurred in the presence of monocytes as well as in their absence, monocyte signaling being replaced by crosslinking of OKT3. Increasing concentrations of AREG down-modulated the concentration of costimulatory B7 molecules (CD80/CD86) and HLA-DR on monocytes. In proliferation assays, CD28 expression on T cells was down-modulated on the application of OKT3 but unaltered by AREG. LcK activation, following OKT3-stimulation, was reduced in T cells that had been coincubated with AREG. The effects of AREG on T-cell phenotypes were also present when monocytes were depleted and OKT3 was crosslinked. The rearranged expression of immunological synapse proteins was accompanied by an alteration of T-cell polarization. Although the proportion of regulatory T cells was not shifted by AREG, IL-17-expressing T cells were significantly enhanced, with a bias toward TH1-polarization. Taken together, these results suggest that AREG acts as an immunoregulatory molecule at the interface between antigen-presenting cells and T cells.

Molecular and Cellular Mechanisms of Arthritis in Children and Adults: New Perspectives on Applied Photobiomodulation

Juvenile idiopathic arthritis and adult rheumatoid arthritis are two major groups with chronic joint pain and inflammation, extra-articular manifestations, and high risk of comorbidities, which can cause physical and ocular disability, as well as create great socio-economic pressure worldwide. The pathogenesis of arthritis manifested in childhood and adulthood is multifactorial, unclear, and overly complex, in which immunity plays an important role. Although there are more and more biological agents with different mechanisms of action for the treatment of arthritis, the results are not as expected, because there are partial responses or non-responsive patients to these compounds, high therapeutic costs, side effects, and so on; therefore, we must turn our attention to other therapeutic modalities. Updating knowledge on molecular and cellular mechanisms in the comparative pathogenesis of chronic arthritis in both children and adults is necessary in the early and correct approach to treatment. Photobiomodulation (PBM) represents a good option, offering cost-effective advantages over drug therapy, with a quicker, more positive response to treatment and no side effects. The successful management of PBM in arthritis is based on the clinician’s ability to evaluate correctly the inflammatory status of the patient, to seek the optimal solution, to choose the best technology with the best physical parameters, and to select the mode of action to target very precisely the immune system and the molecular signaling pathways at the molecular level with the exact amount of quantum light energy in order to obtain the desired immune modulation and the remission of the disease. Light is a very powerful tool in medicine because it can simultaneously target many cascades of immune system activation in comparison with drugs, so PBM can perform very delicate tasks inside our cells to modulate cellular dysfunctions, helping to initiate self-organization phenomena and finally, healing the disease. Interdisciplinary teams should work diligently to meet these needs by also using single-cell imaging devices for multispectral laser photobiomodulation on immune cells.

Update on Abatacept: A Selective Costimulation Modulator for Rheumatoid Arthritis

Objective:

To review and update the pharmacology, pharmacokinetics, safety, precautions, efficacy, and use of abatacept for rheumatoid arthritis (RA).

Data Sources:

Studies and abstracts were identified through MEDLINE, International Pharmaceutical Abstracts, Cochrane databases, and Science Citation Index (1990–April 2007). Key search terms included abatacept, CTLA4–Ig, and BMS 1888667. Information available only in abstract form was retrieved from national and international rheumatology associations. Additional data were obtained from the manufacturer.

Study Selection and Data Extraction:

All available animal and human studies describing the pharmacology of abatacept and human studies describing the pharmacokinetics, pharmacodynamics, efficacy, safety, adverse events, and precautions of abatacept were included.

Data Synthesis:

Abatacept significantly improves the signs and symptoms of moderate-to-severe RA in patients who experienced an Inadequate response to methotrexate or antitumor necrosis factor-α inhibitors. By month 12, approximately 50% of patients achieved remission (defined as a disease activity score <2.6) that was maintained until at least 24 months of therapy. The most common adverse events include headache, upper respiratory tract infections, nausea, and nasopharyngitis. Rare but serious adverse events include serious infections and malignancy.

Conclusions:

Abatacept has documented efficacy and safety in patients with inadequate responses to methotrexate and antitumor necrosis factor agents in both short- and long-term studies. Additional clinical trial and postmarketing evidence is necessary to understand the long-term safety, efficacy, economics, and rote of abatacept in clinical practice.

B cell-specific expression of inducible costimulator ligand is necessary for the induction of arthritis in mice

OBJECTIVE

Inducible costimulator (ICOS)-ICOSL interactions are necessary for activation of Teff cells and follicular helper T (Tfh) cells. ICOSL is expressed on B cells, macrophages, and dendritic cells and can be induced on nonhematopoietic cells. The aim of this study was to determine whether expression of ICOSL on B cells is necessary for the development of proteoglycan (PG)-induced arthritis (PGIA).

METHODS

PGIA was initiated by immunizing wild-type and ICOSL-deficient (ICOSL(-/-) ) or B cell-specific ICOSL(-/-) chimeric BALB/c mice with human PG in adjuvant. The onset and severity of arthritis were monitored over time. CD4+ T cell proliferation and CD4+ T cell cytokine production were measured in vitro after the cells were restimulated with PG. Germinal center (GC) B cells, plasma cells, Tfh cells, and Treg cells were identified by staining with specific antibodies.

RESULTS

Arthritis progression was completely inhibited in both ICOSL(-/-) mice and B cell-specific ICOSL(-/-) chimeric mice. Production of the Teff cell-produced cytokines interferon-γ and interleukin-17 (IL-17) and the antiinflammatory cytokine IL-4 was suppressed. The reduced percentages of GCs and Tfh cells and the decreased production of IL-21 correlated with a decrease in the anti-mouse PG antibody response. However, the percentage of plasma cells was not reduced despite a reduction in IgG responses.

CONCLUSION

These data indicate that the signals provided by ICOSL-expressing B cells to Teff cells and Tfh cells are necessary for the development of arthritis. Thus, therapeutic blockade of ICOSL-ICOS interactions may be an effective strategy for the treatment of rheumatoid arthritis.

Experimental advances in understanding allergic airway inflammation

Asthma is largely an inflammatory disease, with the development of T cell mediated inflammation in the lung following exposure to allergen or other precipitating factors. Currently, the major therapies for this disease are directed either at relief of bronchoconstriction (ie beta-agonists) or are non-specific immunomodulators (ie, corticosteroids). While much attention has been paid to factors that regulate the initiation of an inflammatory response, chronic inflammation may also be due to defects in regulatory mechanisms that limit or terminate immune responses. In this review, we explore the elements controlling both the recruitment of T cells to the lung and their function. Possibilities for future therapeutic intervention are highlighted.

[Personalized medicine for rheumatoid arthritis : serological and clinical patient profiles to optimize B and T cell targeted therapy]

Nowadays B and T-cell directed biologics in addition to TNF inhibitors are established as effective and safe treatment options for rheumatoid arthritis. As shown by the approval of rituximab for the treatment of systemic vasculitis, these drugs can also be useful for the treatment of other systemic autoimmune diseases; however, to optimize therapeutic strategies, predictive factors for treatment response as well as a good characterized safety profile are essential. So far implementation of real personalized medicine is not feasible in the field of rheumatology, but first biomarkers have already been identified and provide promising results. In this context, it has been shown that a B-cell directed therapy with rituximab is more effective in seropositive patients with rheumatoid arthritis. In addition, characterization of the cytokine milieu as well as of circulating and tissue infiltrating B and T-cell subsets might be useful for prediction of treatment response in the near future.

Distinct effects of anti-tumor necrosis factor combined therapy on TH1/TH2 balance in rheumatoid arthritis patients

The immune balance in patients with rheumatoid arthritis (RA), a disease characterized by TH1 dominance, treated by the preferred combined anti-tumor necrosis factor (anti-TNF) and methotrexate (MTX) therapy was evaluated by assessing the chemokine and cytokine receptors as well as apoptosis induction. A meta-analysis of combined therapy by TNF blockers and MTX in 15 RA patients, MTX monotherapy in 20 RA patients, and 11 diagnosed but untreated RA patients was performed by assessing several immune markers in the whole lymphocyte population, as well as in specific CD4 cells, by both flow cytometry and image analysis. A significant downregulation of CXCR3 and IL-12 receptors (both TH1 markers) and a significant increase in the chemokine receptor CCR4 and, to a lesser extent, IL-4R (both TH2 markers) were found; a particularly marked increase was found in patients treated by combined therapy. This phenomenon was pronounced in CD4 cells and was accompanied by a high proportion of apoptotic cells. The therapeutic effect of MTX and TNF blockers may be due to apoptosis induction in lymphocytes infiltrating from the inflammation site and restoring the TH1/TH2 balance.

Golimumab: a new anti-TNF-alpha agent for rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis

Rheumatoid arthritis (RA) is a chronic inflammatory systemic disease characterized by symmetric arthritis leading to progressive erosion of cartilage and bone. Psoriatic arthritis and ankylosing spondylitis are also inflammatory arthritides that belong to the spondyloarthritides. Disease-modifying anti-rheumatic drugs and biologic therapies including anti-TNF agents are used in their treatment. The TNF antagonists have shown rapid and sustained therapeutic responses. However, a substantial number of patients fail to respond to anti-TNF agents or experience side effects. Golimumab is a human monoclonal antibody to TNF-α requiring less frequent administration compared with current anti-TNF products. Various trials have shown promising results in terms of efficacy and safety in methotrexate-naive and -resistant patients with RA as well as in patients previously treated with other anti-TNF agents. The efficacy of golimumab has also been demonstrated in patients with psoriatic arthritis and ankylosing spondylitis.

Description of the efficacy and safety of three new biologics in the treatment of rheumatoid arthritis

English articles on abatacept, golimumab, and tocilizumab in rheumatoid arthritis published between 2002 and 2009 were reviewed systematically. All randomized clinical trials, open-label extensions, meta-analyses, and reviews were examined. There were thirteen articles on abatacept, four on golimumab, and seven on tocilizumab. All three drugs were effective in methotrexate-naïve, methotrexate-incomplete responders, and tumor-necrosis-factor-failure rheumatoid arthritis patients. Of the three, only abatacept has been tested in a head-to-head trial with infliximab, in which it was found to be equivalent to infliximab. Golimumab resulted in a more modest improvement than the others in methotrexate-naïve patients, although no direct comparisons among the three drugs were possible or appropriate. Descriptive analysis of adverse events showed that patients receiving abatacept, golimumab, and tocilizumab were subject to more adverse events than controls overall, as expected. In the abatacept studies, a few cases of tuberculosis, more cardiovascular events and gastrointestinal bleedings and more basal cell carcinoma were seen. Golimumab was associated with more skin rashes and pneumonia, while tocilizumab was associated with increased lipids, more liver-function abnormalities, and neutropenia. These new medications are useful additions to the rheumatologic armamentarium and represent greater convenience (golimumab) or different mechanisms of action (abatacept and tocilizumab) than tumor-necrosis-factor inhibitors for treating rheumatoid arthritis. As expected, some adverse events occur when using these drugs and patients need to be watched carefully.

B cells as a target of immune modulation

B cells have recently been identified as an integral component of the immune system; they play a part in autoimmunity through antigen presentation, antibody secretion, and complement activation. Animal models of multiple sclerosis (MS) suggest that myelin destruction is partly mediated through B cell activation (and plasmablasts). MS patients with evidence of B cell involvement, as compared to those without, tend to have a worse prognosis. Finally, the significant decrease in new gadolinium-enhancing lesions, new T2 lesions, and relapses in MS patients treated with rituximab (a monoclonal antibody against CD20 on B cells) leads us to the conclusion that B cells play an important role in MS and that immune modulation of these cells may ameliorate the disease. This article will explore the role of B cells in MS and the rationale for the development of B cell-targeted therapeutics. MS is an immune-mediated disease that affects over 2 million people worldwide and is the number one cause of disability in young patients. Most therapeutic targets have focused on T cells; however, recently, the focus has shifted to the role of B cells in the pathogenesis of MS and the potential of B cells as a therapeutic target.

B7 costimulation is critical for host control of chronic Mycobacterium tuberculosis infection

Although much is understood regarding the role of B7/CD28 family of costimulatory molecules in regulating host resistance in the context of several pathogens, analogous information with Mycobacterium tuberculosis is lacking. To address the requirements of B7-mediated costimulation in host resistance against tuberculosis, mice deficient in both B7.1 and B7.2 (B7DKO) were aerosol infected with M. tuberculosis Erdman and disease progression was monitored. We report herein that B7DKO mice are initially able to contain the bacterial load in the lung, but exhibit enhanced susceptibility during chronic infection. Despite the early control of bacterial replication, B7DKO mice essentially start off with compromised Th1 immunity and slower granulomatous response in the lung, characterized by markedly reduced lymphocytic infiltration. As the infection progresses from acute phase to the chronic phase, the nascent granulomas in the B7DKO lungs never fully achieve the architecture of granulomas developing in wild-type mice. Instead, lesions spread progressively to involve much of the lung in the B7DKO mice, ultimately leading to necrosis. Thus, early control of M. tuberculosis growth in the lung can occur in the absence of B7 costimulation and is less dependent on Th1 immunity and formation of a granulomatous structure. However, B7 costimulation is critical for long-term containment of infection within lung granulomas. These findings suggest that the use of costimulation-based immunomodulators may have significant repercussions on the induction of host protective immunity against tuberculosis.

B-cell-targeted treatment for multiple sclerosis: mechanism of action and clinical data

Strategies for treating autoimmune disorders are increasingly employing targeted therapies rather than non-specific, multitargeted treatments. Accumulating evidence on the involvement of B lymphocytes in the pathophysiology of autoimmune demyelinating disease has led to a renewed interest in B cells as potential therapeutic targets. In particular, antigen presentation between B cells and T cells, increased trafficking of B cells across the blood-brain barrier, and autoantibodies produced by plasma cells may contribute to the pathophysiology of autoimmune disorders such as multiple sclerosis. Several B-cell-targeted, depletion therapies are currently in development, including rituximab, epratuzumab, diphtheria toxin-single chain Fv (DC2219), belimumab, atacicept, abatacept, and abetimus sodium. Of these agents, only rituximab and abatacept have been evaluated in multiple sclerosis patients. Preliminary results of a phase II trial of rituximab in multiple sclerosis suggest that rituximab is well tolerated and significantly reduces the number of gadolinium enhancing lesions over 24 weeks of treatment. Results of an exploratory analysis suggest the potential promise of abatacept 10 mg/kg for multiple sclerosis. It is expected that future clinical trials will establish a role for B-cell-targeted therapies in the treatment of multiple sclerosis and other autoimmune neurological diseases. This article describes the mechanism of action behind B-cell-targeted depletion therapies in development and reviews available clinical data.

Biological therapy of arthritis and systemic autoimmune diseases

A biológiai terápia lényege, hogy a gyulladás egyetlen, jól meghatározott pontján (pl. egy adott citokin szintjén) hat. Ezáltal a sokszor igen bonyolult mechanizmusokból álló patogenetikai hálózatot egy adott ponton szakítja meg. Ma a rheumatoid arthritis a biológiai terápia szempontjából modellbetegség, mivel a legtöbb szerrel ebben a kórképben próbálkoztak. Ezt követően egyéb arthritisekben (pl. spondylitis ankylopoetica, psoriasisos arthropathia), majd egyes szisztémás autoimmun kórképekben (pl. szisztémás lupus erythematosus, scleroderma, myositisek, vasculitisek, Sjögren-szindróma stb.) kezdték el alkalmazni. A legtöbb kórkép esetében egy központi szereppel bíró citokin, a tumornekrózis faktor-α (TNF-α) gátlószerei állnak a terápia középpontjában. Azonban a biológiai terápia megtervezésekor az adott kórkép patogenezisét (pl. döntően Th1 vagy Th2 jellegét) figyelembe kell venni. Nem véletlen, hogy amíg egyes kórképekben (pl. rheumatoid arthritis, spondylitis ankylopoetica, psoriasis, polymyositis, polyarticularis juvenilis arthritis) döntően a TNF-blokkolók és a T-sejtek elleni gátlás vált be, addig másoknál (pl. lupus, Sjögren-szindróma, dermatomyositis) a B-sejt elleni terápia kecsegtet sikerrel. Ezen összefoglalóban a szerzők áttekintik az arthritisek és szisztémás autoimmun kórképek biológiai terápiájára vonatkozó legfontosabb adatokat. Kitérnek az alkalmazott szerek tulajdonságaira, a hatékonyság és biztonságosság kérdéseire egyaránt.

Abatacept: a novel therapy approved for the treatment of patients with rheumatoid arthritis

An enhanced understanding of the immunopathology of rheumatoid arthritis (RA) has led to the development of novel therapies that target specific events occurring in the immune cascade that underlies the disease. In December 2005, abatacept became the first therapy to be approved by the US Food and Drug Administration for the treatment of adult patients with moderately to severely active RA who have exhibited an inadequate response to traditional disease-modifying antirheumatic drugs or tumor necrosis factor antagonists. This article summarizes the characteristics and clinical profile of abatacept. Abatacept is a fully human soluble recombinant fusion protein that acts by binding to CD80/CD86 on antigen-presenting cells and inhibiting interaction with CD28 on T cells, thus preventing one of the co-stimulatory signals needed for full T-cell activation. It is indicated for reducing signs and symptoms of the disorder, inducing a major clinical response, slowing the progression of structural damage, and improving physical function in this patient population. Data on abatacept compiled to date demonstrate significant efficacy, combined with a consistent safety profile and tolerability, in a wide range of patients with RA, including those with an inadequate response to methotrexate or to tumor necrosis factor antagonists.

Abatacept: A review of a new biologic agent for refractory rheumatoid arthritis for dermatologists

Abatacept is a newly approved treatment for rheumatoid arthritis refractory to other agents. Abatacept is a fusion protein of the cytotoxic T-lymphocyte antigen (CTLA) molecule and immunoglobulin (Ig) G1 that blocks CD28. Specifically, abatacept blocks the CD80 and CD86 ligands on the surface of antigen-presenting cells that must interface with the T-cell's CD28 receptor to activate T cells. Abatacept seems to be more immunosuppressive than tumor necrosis factor alpha blockers. The combination of abatacept and a tumor necrosis factor alpha blocking agent does not seem more effective than either agent alone. Because abatacept has the ability to suppress T-cell function, it has the potential to be a treatment for psoriasis and other autoimmune conditions involving pathologic processes driven by T cells.

Impact of Biologic Agents on Infectious Diseases

Until recently, inflammatory diseases, collagen vascular diseases, inflammatory bowel diseases, and multiple sclerosis were met with a limited offering for treatment. The introduction of biologic agents has revolutionized the approach to these diseases, offering many patients freedom from disease activity staving off resultant destruction to organs and joints with marked improvement in quality of life and disability. This article focuses on the development of serious infections associated with the use of biologic agents. Presented is a synthesis of case series, reports, and systematic reviews to elucidate implicated pathogens and clinical presentations in patients being treated with biologic agents and to form a cursory backbone for prevention and treatment strategies to which clinicians prescribing these agents or encountering patients already on these agents can readily refer. Maintenance of a high index of suspicion is imperative for the prevention and appropriate treatment of serious life-threatening infections in these patients.

Abatacept: A Novel Agent for Rheumatoid Arthritis

Objective:

To evaluate the role of abatacept in the treatment of rheumatoid arthritis (RA) with respect to its pharmacology, pharmacokinetics, clinical efficacy, and adverse effect profile.

Data Sources:

A MEDLINE search (1966–November 2006) was conducted for primary and secondary literature. Search terms included BL125118, CTLA4-Ig, abatacept, and rheumatoid arthritis.

Study Selection and Data Extraction:

All articles retrieved from the data sources were evaluated. The most relevant studies were selected and included in this review.

Data Synthesis:

Abatacept is the first in a new class of RA agents with a unique mechanism of action. It is a selective costimulation modulator that inhibits T cell activation and other inflammatory mediators. This agent has been studied as an adjunct in patients who are receiving disease-modifying antirheumatic drug therapy and in those who have failed tumor necrosis factor-alfa antagonist therapy. Clinical trials were evaluated for information on abatacept's indication, dosing, safety, and efficacy profile.

Conclusions:

Abatacept has been shown to reduce signs and symptoms of RA and improve the condition of patients with moderately to severely active RA.

Immunologic mechanisms in the pathogenesis of rheumatoid arthritis

Although much is known about the etiology and pathogenesis of rheumatoid arthritis (RA), our understanding of the immune pathways remains incomplete. The observed clinical and pathologic manifestations result from activation of several interrelated immune pathways. Current concepts of RA pathogenesis, supported by animal models, laboratory studies, and clinical observation, have reestablished and revised some of the original views. Early proposals emphasized the importance of autoantibodies and immune complexes in the initiation of RA, suggested a role for T cells in the inflammatory response characteristic of RA, and based disease perpetuation on an imbalance in the cytokine networks. We now recognize that each of these interrelated mechanisms significantly contributes to RA pathogenesis, including T cells that can help initiate and perpetuate the disease. This article reviews the major components and immune pathways involved in RA and briefly discusses the animal models that contribute to our understanding. Although a unified theory of RA pathogenesis may not be possible at this time, a paradigm is presented that considers the immune pathways that contribute to disease progression and joint destruction. These pathways may have important implications for treatment, because their modulation by biologic response modifiers (BRMs) directed toward specific targets provides benefits to patients with RA. BRMs are a new class of therapeutic agents derived from biologically active molecules and designed to modulate specific immune or inflammatory pathways. Although currently approved BRMs still have limitations, choosing an appropriate target, possibly early rather than late in the immune response, might result in new and improved therapies for RA.

Biologic therapies in clinical development for the treatment of rheumatoid arthritis

The therapeutic objective in patients with rheumatoid arthritis (RA) is reduction of disease activity with an ultimate goal of disease remission. Limitations of currently available disease-modifying antirheumatic drugs and biologic therapies suggest that there remains an unmet need for agents that advance these goals in a greater proportion of patients. Progress in our understanding of the regulatory molecules and pathways that mediate the immune and inflammatory responses necessary for the initiation and perpetuation of RA has led to the identification of new targets for therapy. It is expected that the therapeutic modulation of these targets, which include proinflammatory cytokines, T and B cells, adhesion molecules, chemokines, and intra- and extracellular signaling pathways, can provide new treatment strategies in patients with RA and other autoimmune disorders. Toward this end, a series of novel agents with diverse mechanisms of action are in development. Although many of these agents are still beyond the clinical horizon, several of them have shown promise in recent trials. This article reviews a few of the many treatment strategies currently being evaluated, which are hoped to lead to greater benefits and better disease management in the clinical setting.