Aktuelle Trends in Design und Entwicklung monoklonaler Antikörper gegen Entzündungsmediatoren zur Therapie der rheumatoiden Arthritis

As mediators of inflammation, cytokines contribute significantly to both the development and the extent of the inflammatory response in rheumatoid arthritis (RA). In addition, they regulate the differentiation of various cells involved in the pathogenesis of this disease. Tumour necrosis factor alpha (TNF α), interleukin (IL)-1 and IL-6 constitute prominent examples of such inflammatory cytokines and have been shown to play an important role in RA. As a consequence, the use of recombinant antibodies targeting these cytokines has revolutionized the treatment of RA. However, a considerable number of RA patients do not respond adequately to therapy with such biologics. Based on this notion, this article summarizes current trends in the design and development of monoclonal antibodies against inflammatory mediators. These include the identification of alterative target structures for anti-cytokine therapies, the specific modification of the antigen-binding CDR of therapeutic antibodies to reduce immunogenicity, alterations of the Fc part and the development of modified antibody fragments to improve the pharmacokinetics and to avoid non-specific immune reactions. Beyond that, efforts are undertaken to optimize the cost of these therapies.     

Liver innate immune cells and insulin resistance: the multiple facets of Kupffer cells

Obesity, which affects 600 million adults worldwide, is a major risk factor for type 2 diabetes (T2D) and insulin resistance. Current therapies for these metabolic disorders include weight management by lifestyle intervention or bariatric surgery and pharmacological treatment with the aim of regulating blood glucose. Probably because of their short‐term effectiveness, these therapies have not been able to stop the rapidly rising prevalence of T2D over the past decades, highlighting an urgent need to develop new therapeutic strategies. The role of immune cells, such as macrophages, in insulin resistance has been extensively studied. Major advances have been made to elucidate the role of adipose tissue macrophages in these pathogeneses. Recently, anti‐inflammatory drugs have been suggested as an alternative treatment for T2D, and clinical trials of these agents are currently ongoing. In addition, results of previous clinical trials using antibodies against inflammatory cytokines, which showed modest effects, are now being rigorously re‐evaluated. However, it is still unclear how liver macrophages [termed Kupffer cells (KCs)], which constitute the major source of macrophages in the body, contribute to the development of insulin resistance. In this review, we will discuss the present understanding of the role of liver immune cells in the development of insulin resistance. We will particularly focus on KCs, which could represent an attractive target for the treatment of metabolic diseases.     

Tumor necrosis factor inhibitors for rheumatoid arthritis.

Tumor necrosis factor antagonists such as infliximab and etanercept represent a new and powerful approach to managing RA. In studies published to date, TNF antagonists appear to be safe and effective agents for short-term therapeutic use in RA. Defining when in the course of RA to use TNF antagonists and determining the effectiveness of combinations of these biologic agents with DMARDs or other cytokine antagonists are areas of current and future studies. Other cytokine antagonists that may be promising subjects for further study are IL-1 antagonists. Like TNF, IL-1 is a member of the inflammatory cascade, but may play a different role in the development of inflammatory arthritis. In animal models, inhibition of TNF suppressed the inflammatory response while IL-1 antagonism prevented joint destruction (2). These results imply that combination therapy providing inhibition of both IL-1 and TNF might be an effective treatment in humans with RA, but clinical trials in humans have not yet been performed. Studies are underway in people with early RA to determine if the new TNF inhibitors are more effective or safer than currently available therapies, such as methotrexate. Other agents that inhibit TNF activity are also being tested at this time in people with RA.     

Impact of the Innate Immune Response in the Actions of Ethanol on the Central Nervous System

The innate immune response in the central nervous system (CNS) participates in both synaptic plasticity and neural damage. Emerging evidence from human and animal studies supports the role of the neuroimmune system response in many actions of ethanol (EtOH) on the CNS. Research studies have shown that alcohol stimulates brain immune cells, microglia, and astrocytes, by activating innate immune receptors Toll‐like receptors (TLRs) and NOD‐like receptors (inflammasome NLRs) triggering signaling pathways, which culminate in the production of pro‐inflammatory cytokines and chemokines that lead to neuroinflammation. This review focuses on evidence that indicates the participation of TLRs and the inflammasome NLRs signaling response in many effects of EtOH on the CNS, such as neuroinflammation associated with brain damage, cognitive and behavioral dysfunction, and adolescent brain development alterations. It also reviews findings that indicate the role of TLR4‐dependent signaling immune molecules in alcohol consumption, reward, and addiction. The research data suggest that overactivation of TLR4 or NLRs increases pro‐inflammatory cytokines and mediators to cause neural damage in the cerebral cortex and hippocampus, while modest TLR4 activation, along with the generation of certain cytokines and chemokines in specific brain areas (e.g., amygdala, ventral tegmental area), modulate neurotransmission, alcohol drinking, and alcohol rewards. Elimination of TLR4 and NLRP3 abolishes many neuroimmune effects of EtOH. Despite much progress being made in this area, there are some research gaps and unanswered questions that this review discusses. Finally, potential therapies that target neuroimmune pathways to treat neuropathological and behavioral consequences of alcohol abuse are also evaluated.     

Methotrexate: mechanism of action in rheumatoid arthritis

Most studies of immune function in rheumatoid arthritis (RA) patients treated with methotrexate (MTX) show only marginal effects on humoral or cellular immune responses. These include measurements of lymphocyte subsets, proliferative responses to mitogens, immunoglobulin production, rheumatoid factor and immune complexes. The mechanism of action of MTX in RA might be more antiinflammatory than immunosuppressive. This is supported by the rapid clinical response to drug treatment and by data from in vitro and animal studies. The inhibition of interleukin-1 (IL-1) activity or other inflammatory cytokines by MTX may play an important role in the antiinflammatory effect of MTX. MTX effects in RA are not fully understood and further studies are needed to clarify its mechanism of action. MTX has crucial effects on the cascade of events initiated by some cytokines (IL-1, IL-6, tumor necrosis factor), which plays a major role in RA and other inflammatory diseases.     

The use of biologic therapies for the management of pediatric asthma

With better understanding of the role of type 2 inflammation in allergic asthma, there has been progress made in the development of new biologic therapies targeting these specific pathways. This review will consider diagnostic criteria for using biologic therapies for pediatric asthma with special emphasis on populations that are likely to benefit the most from particular therapies. With the exception of the anti‐immunoglobulin E, omalizumab, very few studies have been published on the efficacy and safety of biologic therapies in children, particularly anti‐interleukin‐5 (IL5) and anti‐IL4/IL13 therapies. The review will highlight the scarcity of published data in pediatric‐specific populations. In addition, we will consider the cost‐effectiveness as well as potential long‐term consequences of biologic therapies in pediatric asthma.     

Infliximab (Remicade®): from bench to clinical practice. A paradigm shift in rheumatology practice

Infliximab (Remicade®) is a chimeric monoclonal antibody that binds tumour necrosis factor–alpha (TNF‐α) and inhibits its biologic activity. Infliximab has been approved by the FDA for the treatment of a variety of immune‐mediated inflammatory diseases (IMIDs), such as rheumatoid arthritis (RA), Crohn's disease (CD), ankylosing spondylitis (AS), ulcerative colitis (UC), and psoriatic arthritis (PsA). This is a brief review of the development of infliximab primarily in RA and CD; the pathogenesis of RA and CD as applicable to TNF‐α activity; conventional therapies available for RA and CD; early clinical trials and those leading to approval for RA, CD and other indications; coadministration with methotrexate (MTX), and the safety of infliximab as a therapeutic agent for IMIDs.     

New roles for estrogens in rheumatoid arthritis

Sex hormones appear to play an important role as modulators of autoimmune disease onset/perpetuation. Steroid hormones are implicated in the immune response, with estrogens as enhancers at least of humoral immunity, and androgens and progesterone (and glucocorticoids) as natural immune suppressors. Serum levels of estrogens have been found to be normal in rheumatoid arthritis (RA) patients. Synovial fluid levels (SF) of proinflammatory estrogens relative to androgens are significantly elevated in both male and female RA patients as compared to controls, which is most probably due to an increase in local aromatase activity. Thus, available steroid pre-hormones are rapidly converted to proinflammatory estrogens in the synovial tissue in the presence of inflammatory cytokines (i.e. TNF alpha, IL-1, IL-6). The increased estrogen concentrations observed in RA SF of both sexes are characterized mainly by the hydroxylated forms, in particular 16 alpha-hydroxyestrone, showing a mitogenic stimulating role. Indeed, recent studies by us indicate that 17-beta estradiol (E2) clearly enhanced the expression of markers of cell growth and proliferation, whereas testosterone (T) induced an increase in markers indicating DNA damage and apoptosis. In particular, our data further shows that the enhancing role of estrogens on the immune/inflammatory response is exerted by activating the NFkB complex. In conclusion, locally increased estrogens may exert activating effects on synovial cell proliferation, including macrophages and fibroblasts, suggesting new roles for estrogens in RA.     

Biologic therapy of inflammatory bowel disease

Biological therapies in inflammatory bowel disease reflect the exponential advancement in understanding the human intestinal immune system and particularly the biology of intestinal inflammation during the past decade. The better understanding of the mechanisms of inflammatory bowel disease has evolved from desriptive clinical data and genetically engineered animal models. It led to great interest in the evaluation of a variety of new therapeutic agents with novel actions. This review will discuss the mechanisms of biologicals (antibodies against pro-inflammatory cytokines, T cell antibodies, anti-inflammtory cytokines, adhesion molecule blockers, growth factors, hormones, colony stimulating factors, fusion proteins, anti-sense oligonucleotides, trefoil peptides, immunostimulatory [ISS] DNA) used in the treatment of inflammatory bowel disease and summarizes the available data on established biologic therapies as well as investigational agents and briefly touch on probiotics. Based on the data discussed, it seems that biologicals will play an important role in managing inflammatory bowel disease in the near future.     

Differential Effects of Inflammation on Bone and Response to Biologics in Rheumatoid Arthritis and Spondyloarthritis

Purpose of review

We review the pathways, cytokines, and concepts important to the pathogenesis of bone resorption and formation in rheumatoid arthritis (RA) and spondyloarthritis (SpA).

Recent findings

Research in bone biology has shed light on the pathogenesis of the joint destruction that occurs in RA and in peripheral SpA. However, understanding the mechanisms behind the bone formation seen in peripheral and axial SpA has been challenging. Mouse models have been used to gain an understanding of key signaling pathways, cytokines and cells regulating inflammation in these diseases. Biologic therapies directed against these targets have been developed to control both inflammation and effects on bone.

Summary

Although biologic therapies improve joint inflammation in both RA and SpA, leading to a decrease in pain and improving quality of life for patients, the long-term effects of such therapies must also be evaluated by assessing their impact on structural progression. Inhibition of radiographic progression in both RA and peripheral SpA has been easier to demonstrate than in axial SpA. Here, we discuss the similarities and differences among biologic therapies as they pertain to radiographic progression.

     

Interstitial lung disease in rheumatoid arthritis: Current concepts in pathogenesis,diagnosis and therapeutics

Rheumatoid arthritis (RA) is the most common chronic autoimmune inflammatory joint disease. RA-associated interstitial lung disease (RA-ILD) is a major extra-articular complication and causes symptoms that lead to a deterioration in the quality of life, high utilization of health resources, and an increased risk of earlier mortality. Early in the course of RA-ILD, symptoms are highly variable, making the diagnosis difficult. Therefore, a rational diagnostic strategy that combines an adequate clinical assessment with the appropriate use of clinical tests, including pulmonary function tests and high-resolution computed tomography, should be used. In special cases, lung biopsy or bronchioalveolar lavage should be performed to achieve an early diagnosis. Several distinct histopathological subtypes of RA-ILD are currently recognized. These subtypes also have different clinical presentations, which vary in therapeutic response and prognosis. This article reviews current evidence about the epidemiology of RA-ILD and discusses the varying prevalence rates observed in different studies. Additionally, aspects of RA-ILD pathogenesis, including the role of cytokines and other molecules such as autoantibodies, as well as the evidence linking several drugs used to treat RA with lung damage will be discussed. Some aspects of the clinical characteristics of RA-ILD are noted, and diagnostic strategies are reviewed. Finally, this article analyzes current treatments for RA-ILD, including immunosuppressive therapies and biologic agents, as well as other therapeutic modalities. The prognosis of this severe complication of RA is discussed. Additionally, this paper examines updated evidence from studies identifying an association between drugs used for the treatment of RA and the development of ILD.     

New insights to the mechanisms underlying atherosclerosis in rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory circumstance, which has been associated with increased risk of cardiovascular disease (CVD). Although RA management has been promoted, mortality rate due to CVD remains remarkable. Approximately, 50% of premature death cases in RA are attributable to CVD. RA patients develop atherosclerosis in a greater amount than the general population. Moreover, atherosclerotic lesions develop rapidly in RA patients and might be more susceptible to rupture. The inflammatory condition of RA, such as cytokines, abnormally activated immune cells, play a role in the initiation, perpetuation and exacerbation of atherosclerosis. RA and CVD have genetic and environmental contributing risk factors in common, implying to potential coincidence of both disorders. Accelerated atherosclerosis in RA is attributed to inflammation, which carries its role out both through modulation of traditional risk factors and direct effect on the vessel wall. Hence, anti‐inflammatory medications in RA like tumor necrosis factor blockers might have a beneficial effect on preventing cardiovascular development. Increasing age, smoking, hypertension, male gender, hypercholesterolemia and diabetes are enumerated as traditional CVD risk factors. Hopefully, further understanding of the cardiovascular risk factors by perceiving the disease conditions behind CVD, will improve management of cardiovascular risks in patients with RA.     

The impact of new biologicals in the treatment of rheumatoid arthritis

The past decade has seen a shift in the paradigm for RA management. DMARDs have been introduced at earlier stages of disease in an effort to slow or stop radiographic disease progression before irreversible joint damage, work disability, functional decline and other adverse outcomes are seen. Although often effective, DMARDs have been limited in treatment durability over the long term due to side-effects and declining efficacy. Combination regimens, often involving weekly methotrexate as the anchor drug, have been used increasingly to overcome the limitations of DMARD monotherapy. The advent of biological therapies that specifically target key proinflammatory cytokines, believed to be important in disease pathogenesis, provides several new treatment options. In controlled clinical trials, the IL-1 blocker anakinra (r-metHuIL-1ra) significantly reduced the clinical signs and symptoms of RA when used alone or in combination with weekly methotrexate. The TNF inhibitors etanercept, infliximab and adalimumab have shown similar efficacy; indeed, higher response rates for clinical and radiological parameters have been seen with the TNF blockers. Importantly, each of these biological response modifiers significantly reduced radiographic disease progression in 6- to 12-month studies, and some radiographic data extend to 24 months. Despite these promising findings, it remains to be determined whether slowing radiographic progression will translate into significant improvements in long-term outcomes.     

Clinical perspectives--biologics in IBD: What's all the fuss?

Up until the present time, agents with relatively nonspecific anti-inflammatory or immunomodulatory effects such as 5-acetylsalicylic acid, corticosteroids and azathioprine have been the mainstay of inflammatory bowel disease medical therapy. These drugs have been quite useful in one or more clinical settings, but they have been hampered by modest efficacy, significant toxicity or both. With greater understanding of the specific pathways of the gut mucosal immune response, it is hoped that newer biologic response modifiers will provide better efficacy, with an improved adverse event profile compared with older existing therapies. This article examines the evidence behind the use of biologic therapies such as anti-tumour necrosis factor-alpha, interleukin-10, interleukin-11, anti-integrin antibody and antisense intercellular adhesion molecule-1 oligonucleotide.     

Does a biological link exist between periodontitis and rheumatoid arthritis?

Periodontitis or Periodontal disease(PD) and Rheumatoid arthritis(RA) are two the most common chronic inflammatory diseases. Periodontitis is a biofilm associated destructive inflammatory disease of the periodontium caused by specific microorganisms. Rheumatoid arthritis is an autoimmune condition and is identified by elevated serum autoantibody titre directed against citrullinated peptides or rheumatoid factor. Periodontitis may involve some elements of autoimmunity. Recent studies have established that PD and RA show a common pathway and could be closely associated through a common dysregulation and dysfunction in inflammatory mechanism. The enzyme peptidyl arginine deiminase(PAD), expressed by Porphyromonas gingivalis(P. gingivalis) is responsible for the enzymatic deimination of arginine residuals to citrulline resulting in protein citrullination and its increased accumulation in RA.Citrullination by PAD may act as a putative biologic link between PD and RA. Association of Human leukocytic antigen-DR4 antigen has been established both with RA and PD. Several interleukins and inflammatory mediators(ILs) and Nuclear factor kappa beta ligand are linked to these common chronic inflammatory diseases. Antibodies directed against heat shock protein(hsp 70 ab) of P. gingivalis, P. melanogenicus and P. intermedia are raised in PD as well as RA. Both the conditions share many pathological and immunological similarities. Bacterial infection, genetic susceptibility, altered immune reaction and inflammatory mediators considered responsible for RA are also associated with PD. So it is plausible that a biological link may exist between PD and RA. Therapies aimed at modifying the expression and effect of inflammatory mediators and effector molecules such as matrix metalloproteinases, proinflammatory cytokines and autoantibodies of structural proteins may probably reduce the severity of both RA and PD.     

Rheumatoid arthritis. From bench to bedside

In the last decade, basic science has unraveled in considerable detail the inflammatory and related processes ongoing in RA synovial membrane. This has translated to cytokine targeting therapies with some effect. How much more can be achieved? It may be argued that the order of improvement obtained thus far obviates further study. This ignores the potential to achieve a far greater magnitude of disease suppression. Our objective in innovating biologic therapies should now be routine achievement of American College of Rheumatology "70% responses" or disease remission and design of patient-specific therapy based on individual disease characteristics. We have not yet explored the potential contained in combination biologic approaches, particularly when different processes within the disease are targeted. Cocktails might target T cells, cytokines, and angiogenic factors, for example. These developments must also be seen in the context of the information soon to be available from the Human Genome Project. The impact of gene array analysis and similar techniques that facilitate simultaneous evaluation of thousands of gene activation events is also awaited. This, in turn, is likely to require considerable development in our use of information technology, because the volume of information will soon (or may already) be prohibitive. Finally, encompassing genomic and bioinformatic approaches should certainly challenge our basic diagnostic criteria such that it ultimately may be necessary to consider our clinical diagnoses on the basis not only of clinical phenotype but of genotype and biologic response profile. Through this rapid evolution, close communication between physician and scientist is essential.     

Cytokine response in inflammatory myopathies

After background information about pathologic findings, this review focuses on the cytokine response in the pathogenesis of polymyositis and dermatomyositis. Cytokines are important mediators of the immune response and play a key role in these diseases by acting on inflammatory immune cells, muscle cells, and vessel cells. Various cytokines are found in myositis samples, in particular interleukin-1 and tumor necrosis factor-α, which are associated with the migration, differentiation, and maturation of inflammatory cells. Recent advances indicate that the muscle cell itself could participate in the inflammatory process. Cytokines promote changes in muscle metabolism resulting in a self-sustaining inflammatory response. Accordingly, cytokines may represent new targets for therapies.     

The effect of neutralizing antibodies on the sustainable efficacy of biologic therapies: what’s in it for African and Middle Eastern rheumatologists

Over the last decade, biologic therapeutic proteins have advanced the treatment of diseases such as rheumatoid arthritis (RA). Therapeutic antibodies such as infliximab, adalimumab, rituximab, tocilizumab, golimumab, certolizumab pegol, the receptor construct etanercept, and abatacept, an anticluster of differentiation (CD)80/anti-CD86 fusion protein, are used as treatment for RA and ankylosing spondylitis (AS). Infliximab, adalimumab, golimumab, certolizumab pegol, and etanercept are inhibitors of tumor necrosis factor (TNF), a key regulator of inflammation. Left untreated, progression of rheumatic diseases due to inflammation can lead to irreversible joint damage and serious disability. One limitation for the use of therapeutic antibodies is immunogenicity, the induction of antibodies by the adaptive immune system in response to foreign substances. The development of antidrug antibodies (ADAs) has a varying impact on the clinical efficacy of biologic agents for the treatment of RA and AS, depending on whether the ADAs are neutralizing or non-neutralizing. Studies have indicated that neutralizing ADAs are associated with a reduced efficacy, decreased drug survival, increased instances of dose escalation, and adverse events. Comparison studies of anti-TNF biologics have demonstrated that each drug has a different sustained efficacy profile depending on immunogenicity. The purpose of this review is to provide rheumatologists with information regarding the effect of neutralizing antibodies on the sustainable efficacy of anti-TNF biologic therapies. This information will be of value to practicing rheumatologists in Africa and the Middle East who should take into account the potential for changes in the efficacy and safety of biologic therapies and closely monitor patients under their care.     

Multiplex serum cytokine monitoring as a prognostic tool in rheumatoid arthritis

OBJECTIVE: Early optimized therapy of rheumatoid arthritis (RA) results in improved outcomes. The initiation of optimized therapy is hindered by the difficulty of early diagnosis and the limitations of current disease activity and therapeutic response assessment tools. Identifying patients requiring early combination DMARD/biologic therapy is currently a significant clinical challenge given the lack of definitive prognostic criteria. Since cytokines are soluble intracellular signaling molecules that modulate disease pathology in RA, we tested the recent conjecture that en mass serum cyto-kine measurement and monitoring will provide a useful tool for effective therapeutic management in RA. METHODS: We assayed the levels of 16 serum cytokines in 18 RA patients treated prospectively with methotrexate and from 18 unaffected controls. Specific mechanistic aspects of inflammatory pathology in the periphery could be discerned on a patient-specific basis from patients' serum cytokine profiles, information that may aid in the design of anti-cytokine biologic therapy. A serum Cytokine Activity Index (CAI) was also created using multi-variant analysis methods. RESULTS: Distinct cytokines were significantly elevated in RA patients relative to controls, and three distinct clusters with correlations to disease activity were identified. The Cytokine Activity Index correlated well with the therapeutic res-ponse; responders and non-responders in this cohort were distinguishable as early as one month post initiation of methotrexate therapy, well before clinical assessments of response are commonly completed. CONCLUSION: Clinical assessment tools could be derived from this approach that may provide a means to continually track patients, allowing intervention strategies to be better evaluated on a patient-specific basis and to identify residual cytokine activity that could be used to guide combination therapy.