Arthritis Research

Tumor necrosis factor alpha (TNF-alpha) is an inflammatory cytokine that has been implicated in a variety of rheumatic and inflammatory diseases. New understanding of the importance of TNF-alpha in the pathophysiology of rheumatoid arthritis and Crohn's disease led to the development of a new class of targeted anti-TNF therapies. Anti-TNF-alpha agents including etanercept (a fusion protein of the p75 TNF receptor and IgG1) and infliximab (a chimeric monoclonal antibody specific for TNF-alpha) have been approved for the treatment of rheumatoid arthritis...

Several agents show an effect on reducing radiographic progression in rheumatoid arthritis. It is tempting to retrospectively compare the effects of these agents on radiographic progression across clinical trials. However, there are several limitations in interpreting and comparing radiographic results across clinical trials. These limitations, including study designs, patient characteristics, durations of follow-up, scoring methodologies, reader reliability, radiograph sequence, handling of missing data, and data presentation, will be discussed...

Since the initial characterization of tumor necrosis factor alpha (TNFalpha), it has become clear that TNFalpha has diverse biologic activity. The realization that TNFalpha plays a role in rheumatoid arthritis (RA) has led to the development of anti-TNF agents for the treatment of RA. Infliximab, a chimeric monoclonal antibody that specifically, and with high affinity, binds to TNFalpha and neutralizes the cytokine, is currently approved for the treatment of RA and Crohn's disease, another immune-inflammatory disorder...

With the introduction of new disease-modifying antirheumatic drugs (DMARDs) and other therapeutic agents, the management of rheumatoid arthritis (RA) has shifted toward earlier, more aggressive therapy. The ultimate goal is to prevent structural joint damage that leads to pain and functional disability. Early diagnosis of RA is therefore essential, and early DMARD treatment combined with nonsteroidal anti-inflammatory drugs is recommended. Combination DMARD regimens and new biologic agents (anti-tumor necrosis factor [TNF] therapies [infliximab, etanercept] and the interleukin [IL]-1 antagonist [anakinra]) have emerged as viable options for early treatment of RA patients...

Although functional outcome is frequently discussed and written about, it is often not clear what functional outcome is and how it can be measured. This paper introduces the concept of latent and observed measures of functional disability, and distinguishes between disability as a process measure and disability as an outcome measure. Using the Health Assessment Questionnaire as the main functional outcome measure in rheumatoid arthritis, we propose and discuss several methods for determining disability, and describe the implications of altering the disability course...

Early diagnosis of rheumatoid arthritis (RA) combined with early initiation of an appropriate treatment regimen is acknowledged as an important factor in improving clinical outcomes in patients with RA. Early diagnosis allows treatment intervention to occur sooner in order to inhibit the progression of structural joint damage as well as providing improved patient quality of life. Unfortunately, early diagnosis has been challenging due to the non-specific signs and symptoms associated with many polyarthropathies and the lack of accurate definitive diagnostic tests that can accurately classify RA at presentation...

Autoantibodies are proven useful diagnostic tools for a variety of rheumatic and non-rheumatic autoimmune disorders. However, a highly specific marker autoantibody for rheumatoid arthritis (RA) has not yet been determined. The presence of rheumatoid factors is currently used as a marker for RA. However, rheumatoid factors have modest specificity (~70%) for the disease. In recent years, several newly characterized autoantibodies have become promising candidates as diagnostic indicators for RA. Antikeratin, anticitrullinated peptides, anti-RA33, anti-Sa, and anti-p68 autoantibodies have been shown to have >90% specificity for RA...

There are currently unprecedented opportunities to treat rheumatoid arthritis using well-designed, highly effective, targeted therapies. This will result in a substantial improvement in the outcome of this disorder for most affected individuals, if they can afford these therapies. Yet our lack of understanding of the basic mechanisms that initiate and sustain this disease remains a major obstacle in the search for a definitive cure. It is possible, if not likely, that our best approach will be to identify individuals at risk and devise reliable, safe methods of preventing the disease before it occurs...

Complement is implicated in the pathogenesis of systemic lupus erythematosus (SLE) in several ways and may act as both friend and foe. Homozygous deficiency of any of the proteins of the classical pathway is causally associated with susceptibility to the development of SLE, especially deficiency of the earliest proteins of the activation pathway. However, complement is also implicated in the effector inflammatory phase of the autoimmune response that characterizes the disease. Complement proteins are deposited in inflamed tissues and, in experimental models, inhibition of C5 ameliorates disease in a murine model...

Single nucleotide polymorphisms are the most important and basic form of variation in the genome, and they are responsible for genetic effects that produce susceptibility to most autoimmune diseases. The rapid development of databases containing very large numbers of single nucleotide polymorphisms, and the characterization of haplotypes and patterns of linkage disequilibrium throughout the genome, provide a unique opportunity to advance association strategies in common disease rapidly over the next few years...

The prevalence of rheumatoid arthritis (RA) is relatively constant in many populations, at 0.5-1.0%. However, a high prevalence of RA has been reported in the Pima Indians (5.3%) and in the Chippewa Indians (6.8%). In contrast, low occurrences have been reported in populations from China and Japan. These data support a genetic role in disease risk. Studies have so far shown that the familial recurrence risk in RA is small compared with other autoimmune diseases. The main genetic risk factor of RA is the HLA DRB1 alleles, and this has consistently been shown in many populations throughout the world...

Systemic lupus erythematosus (SLE) is the paradigm of a multisystem autoimmune disease in which genetic factors strongly influence susceptibility. Through genome scans and congenic dissection, numerous loci associated with lupus susceptibility have been defined and the complexity of the inheritance of this disease has been revealed. In this review, we provide a brief description of animal models of SLE, both spontaneous models and synthetic models, with an emphasis on the B6 congenic model derived from analyses of the NZM2410 strain...

Signal transduction induced by tumor necrosis factor (TNF) family members and their receptors has been an intensive area of research for several years. The major impact of these studies has been the delineation of apoptotic and cell survival signaling pathways. These discoveries, coupled with major advances in the study of mammalian apoptotic machinery, constitute a promising blueprint of the molecular network governing the fate of all living cells. In this review, we concentrate on the fate of cells in the immune system, where regulation of cell death and cell survival is a frequent and important exercise...

IL-6 is a pleiotropic cytokine with a wide range of biological activities in immune regulation, hematopoiesis, inflammation, and oncogenesis. Its activities are shared by IL-6-related cytokines such as leukemia inhibitory factor and oncostatin M. The pleiotropy and redundancy of IL-6 functions have been identified by using a unique receptor system comprising two functional proteins: an IL-6 receptor (IL-6R) and gp130, the common signal transducer of cytokines related to IL-6. Signal transduction through gp130 is mediated by two pathways: the JAK-STAT (Janus family tyrosine kinase-signal transducer and activator of transcription) pathway and the Ras mitogen-activated protein kinase pathway...

Regulation of osteoclast differentiation is an aspect central to the understanding of the pathogenesis and the treatment of bone diseases such as autoimmune arthritis and osteoporosis. In fact, excessive signaling by RANKL (receptor activator of nuclear factor kappaB ligand), a member of the tumor necrosis factor (TNF) family essential for osteoclastogenesis, may contribute to such pathological conditions. Here we summarize our current work on the negative regulation of osteoclastogenesis by unique signaling crosstalk between RANKL and interferons (IFNs)...

The elucidation of the signalling pathways involved in inflammatory diseases, such as rheumatoid arthritis, could provide long sought after targets for therapeutic intervention. Gene regulation is complex and varies depending on the cell type, as well as the signal eliciting gene activation. However, cells from certain lineages, such as macrophages, are specialised to degrade exogenous material and consequently do not easily transfect. Methods for high-efficiency gene transfer into primary cells of various lineages and disease states are desirable, as they remove the uncertainties associated with using transformed cell lines...

The strong association between specific alleles encoded within the MHC class II region and the development of rheumatoid arthritis (RA) has provided the best evidence to date that CD4+ T cells play a role in the pathogenesis of this chronic inflammatory disease. However, the unusual phenotype of synovial T cells, including their profound proliferative hyporesponsiveness to TCR ligation, has challenged the notion that T-cell effector responses are driven by cognate cartilage antigens in inflamed synovial joints...

Signals emanating from receptors of the tumor necrosis factor/nerve growth factor (TNF/NGF) family control practically all aspects of immune defense and, as such, constitute potential targets for therapeutic intervention through rational drug design. Indeed, arrest of these signals by blocking ligand-receptor interactions enables effective suppression of a variety of activities that are implicated in various pathologies, such as T and B lymphocyte activation and growth, inflammation, fibroblast proliferation, and cell death...

This paper presents a brief review of several lines of evidence suggesting that chemokine receptors on dendritic cells play an important role in breaking tolerance to self and in inducing autoimmunity. First, we have shown that an idiotypic self-antigen obtained from malignant murine lymphomas, when covalently linked to selected chemokines or defensins that interact with receptors on immature dendritic cells (iDCs), has the capacity to break tolerance to self and induce humoral or cell-mediated anti-tumor responses...

Several groups have documented the expression of cytokines in rheumatoid arthritis synovial tissue over the past 15 years or so. These studies have indicated that most cytokines examined are expressed at the mRNA levels at least, and many other cytokines are found in abundance as proteins. Our attention has recently focused on the mechanisms that induce and regulate tumour necrosis factor and IL-10. Other workers and ourselves have found that cell-cell contact is an important signal for the induction of cytokines, and our work has demonstrated that tumour necrosis factor and IL-10 production in rheumatoid arthritis synovial joint cells cultures is dependent on T cell/macrophage interaction...