Increased Expression of Down-Regulatory CTLA-4 Molecule on T Lymphocytes from Rheumatoid Synovial Compartment

Since the CTLA-4 molecule expressed on activated T lymphocytes has recently been suggested to be an important negative regulator in autoimmune diseases, this study was undertaken to investigate the expression and function of CTLA-4 on synovial T cells from patients with rheumatoid arthritis. CTLA-4-expressing T cells were detected using a dual fluorescence flow cytometric method. Only a small percentage of peripheral blood T cells from patients with rheumatoid arthritis had detectable surface CTLA-4 expression (mean +/- SD, 1. 89 +/- 1.92%). However, the levels of CTLA-4-positive T cells was increased significantly in rheumatoid synovial fluids (5.44 +/- 4. 96%) and synovial membranes (28.76 +/- 14.30%). To explore the role of CTLA-4 molecule in the inflammation of rheumatoid joints, CTLA-4 was blocked with anti-CTLA-4 antibody to assess its effects on the production of tumour necrosis factor alpha and interleukin 1beta in synovial fluid mononuclear cell culture. The addition of anti-CTLA-4 antibody enhanced the production of tumour necrosis factor alpha and interleukin 1beta in a dose-dependent manner. The data suggest that the expression of CTLA-4 plays a down-regulatory role in rheumatoid articular inflammation. We thus concluded that CTLA-4 was up-regulated on synovial T cells from patients with RA, and the increased CTLA-4 expression might exert a down-regulation effect on tumour necrosis factor alpha and interleukin 1beta production.     

Current Status of Gene Therapy for Rheumatoid Arthritis

Despite the high prevalence of the disease, at present little effective pharmacological treatment of rheumatoid arthritis is available. Novel approaches utilising biological agents have resulted in the development of new antiarthritic and antiinflammatory agents, such as tumour necrosis factor-alpha (TNFalpha)-specific antibodies and interleukin-1 receptor antagonist (IL-1ra). Local gene therapy not only allows the pharmaceutical use of these biologicals, but also allows for continuous drug supply, which is necessary for chronic diseases like rheumatoid arthritis. We discuss the basics of rheumatoid arthritis therapy, candidate genes and possible gene transfer methods. A current clinical gene therapy trial is focusing on the IL-1 system using IL-1ra as a transgene. The transfer system, clinical protocol and preliminary results are described. After treatment of 11 patients we feel that gene therapy will offer potential as a new avenue to treat rheumatoid arthritis.     

Role of B Cells in the Pathogenesis of Rheumatoid Arthritis

In patients with rheumatoid arthritis, chronic inflammation in affected joints may lead to the development of tertiary lymphoid tissue. A micro-environment is generated in the synovial membrane which supports the activation and differentiation of B cells into plasma cells. Through a process of affinity maturation, plasma cells may be generated locally which secrete antibodies of high affinity. Rheumatoid arthritis is characterised by autoantibodies specific for self immunoglobulin. These rheumatoid factors form large antigen/antibody complexes which may enhance the process of joint destruction. The poor prognosis of rheumatoid factor-positive patients is indicitive of the critical role of immunoglobulin complexes in the continuous stimulation of the immune system and thus of the inflammatory processes. In general, treatment of patients with rheumatoid arthritis aims at suppressing inflammation. The currently most successful reagents are those which interfere with the network of cytokines, such as tumour necrosis factor or interleukin-1 receptor antagonists. Only recently have immunosuppressive therapies targeted directly at the B cell response been developed. These first studies suggest that therapies which directly affect the humoral immune response are of great therapeutic potential in the treatment of patients with rheumatoid arthritis.     

The role of Natural Killer cells in the pathogenesis of rheumatoid arthritis: major contributors or essential homeostatic modulators?

Natural Killer (NK) cells are lymphocytes of the innate immune system, originally described by their capacity to control tumour cells and eliminate virus-infected cells. However accumulating evidence suggests that NK cells can interact with various components of the immune system and play a critical role in autoimmune diseases by limiting or exacerbating immune responses. Rheumatoid arthritis is a chronic inflammatory disease characterised by joint inflammation and cartilage and bone destruction. NK cells are enriched within the joints of patients with rheumatoid arthritis but how they contribute to disease pathology is currently not fully elucidated. This review will outline the current understanding of NK cell biology and how these cells may modulate disease pathogenesis in rheumatoid arthritis through interactions with other immune cells.     

Cytokines in synovial fluid: II. The presence of tumour necrosis factor and interferon.

Cytokine-specific monoclonal antibodies were used in enzyme-linked immunoadsorbant assays (ELISA) to examine a variety of synovial fluids for the presence of cytokines which might be expected to play some part in the pathology of arthritis. Low, but significant, levels of tumour necrosis factor alpha (TNF-alpha) were present in the majority of synovial fluids obtained from rheumatoid arthritis patients with a sero-positive history. Low levels of interferon (IFN)-alpha and IFN-gamma were also detected, but only IFN-alpha was significantly increased in the sero-positive group. Tumour necrosis factor beta (TNF-beta) was present only in trace amounts. These results suggest that the presence of cytokines, such as TNF-alpha and IFN-alpha in synovial fluid may be associated with tissue changes observed in rheumatoid joint disease and thus contribute to the pathology of the arthritis, but support evidence for the minimal role likely to be played by IFN-gamma in the joint pathology of rheumatoid arthritis.     

Analysing the effect of novel therapies on cytokine expression in experimental arthritis

Type II collagen-induced arthritis (CIA) is an animal model of rheumatoid arthritis that has been used extensively to address questions of disease pathogenesis and to validate novel therapeutic targets. Susceptibility to CIA is strongly associated with major histocompatibility complex class II genes, and the development of arthritis is accompanied by a robust T- and B-cell response to type II collagen. The main pathological features of CIA include proliferative synovitis with infiltration of inflammatory cells, pannus formation, cartilage degradation, erosion of bone and fibrosis. Pro-inflammatory cytokines, such as tumour necrosis factor alpha and interleukin-1beta, are expressed in the arthritic joints in both murine CIA and human rheumatoid arthritis, and blockade of these molecules results in amelioration of disease. Hence, there is a great deal of interest in the development of small-molecular-weight inhibitors of pro-inflammatory cytokines. There is also interest in the development and testing of drugs with the capacity to modulate the immune pathways involved in driving the inflammatory response in arthritis. For these reasons, there is a need to monitor the effect of novel treatments on cytokine expression in vivo. In this review, we outline the various techniques used to detect cytokines in experimental arthritis and describe how these techniques have been used to quantify changes in cytokine expression following therapeutic intervention.     

Juvenile Idiopathic Arthritis

Overexpression of cytokines in inflamed joints plays an important role in joint inflammation and in damage to articular tissue. Biological agents aimed at specifically antagonising tumour necrosis factor (TNF) are effective in the treatment of adult rheumatoid arthritis. A recent trial of etanercept, a genetically engineered fusion protein consisting of the Fc domain of human IgG1 and the TNF receptor p75, has demonstrated that this agent is also well tolerated and effective in patients with juvenile idiopathic arthritis (JIA). Etanercept offers a promising new alternative for patients with JIA who have persistently active arthritis despite treatment with methotrexate. Further studies are needed to clarify whether etanercept is equally effective in the various onset types of JIA (oligoarthritis, polyarthritis and systemic arthritis), whether it can modify disease progression and whether it can be administered safely for long periods of time to children.     

Parthenolide Inhibits Proliferation of Fibroblast-Like Synoviocytes In Vitro

Parthenolide is a bioactive constituent of an aromatic herb Feverfew (Tanacetum parthenium). It has been found that both parthenolide and extract of feverfew have anti-inflammatory and antinociceptive properties. Moreover, they demonstrate antiproliferative activities on different human tumour cells. The massive hyperplasia of synovial fibroblasts is the one of the most striking features of rheumatoid arthritis. It is not known whether this is due to the proliferation of synovial fibroblasts or to defective apoptosis. We investigated the effect of parthenolide on the proliferation of rabbit synoviocytes cell line HIG-82, rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) and human skin fibroblasts (HSF) in vitro. Cell proliferation was assessed by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 5'-bromo-2'-deoxy-uridine methods. Parthenolide inhibited proliferation of HIG-82 and human RA-FLS. The proliferation of HSF was inhibited less effectively. The antiproliferative potential of parthenolide was demonstrated.     

滑膜成纤维细胞在类风湿性关节炎发病中的作用

类风湿性关节炎是复杂的多系统疾病,近年来,越来越多的证据表明,滑膜成纤维细胞在类风湿性关节炎中过度增殖,介导炎症反应,造成关节结构破坏。滑膜成纤维细胞在类风湿性关节炎发病过程中具有重要的作用。     

Association and Expression Study of <Emphasis Type="Italic">PRKCH</Emphasis> Gene in a French Caucasian Population with Rheumatoid Arthritis

We study the association between three protein kinase C, eta gene polymorphisms (+8134C/T, rs912620, rs959728), and susceptibility to rheumatoid arthritis. One hundred French Caucasian rheumatoid arthritis trio families were genotyped. Relative quantification of protein kinase C, eta mRNA expression was performed from whole blood in 24 unrelated rheumatoid arthritis patients and in 16 healthy controls. Our results showed no significant association or linkage between the protein kinase C, eta polymorphisms, and rheumatoid arthritis. The protein kinase C, eta mRNA was expressed at lower level in rheumatoid arthritis unrelated patients than in healthy controls. This study shows that protein kinase C, eta gene is not a Rheumatoid Arthritis major susceptibility genetic factor in the French Caucasian population. Furthermore, the lower expression of this gene in rheumatoid arthritis patients comparing to healthy controls suggests that protein kinase C, eta could be associated with the patho-physiologic mechanism of rheumatoid arthritis.     

The Identification of Germinal Centres and Follicular Dendritic Cell Networks in Rheumatoid Synovial Tissue

We document here the identification of germinal centres with dark and light zones, a follicular dendritic cell network and clonal expansion in the synovium of rheumatoid arthritis patients. Synovial tissue from 24 patients suffering from rheumatoid arthritis or the polyarticular form of juvenile rheumatoid arthritis were screened for the presence of lymphoid follicles. The synovial tissues of 14 patients contained follicles and four of these had germinal centres and a follicular dendritic cell network. There was a statistically significant association between follicles in the synovium and the presence of rheumatoid factor autoantibodies in the patients' serum indicating a link between local germinal centre formation and the presence of pathological rheumatoid factors. Nucleotide sequencing of monoclonal rheumatoid factors from one of the patients' synovial tissue which contained germinal centres clearly supports the possibility that these rheumatoid factors have gone through a germinal centre reaction. While rheumatoid factors from healthy immunized donors are regulated through a tolerization mechanism which selects against replacement mutations and does not allow affinity maturation, synovial rheumatoid factors seem to lack this tolerization mechanism. The formation of germinal centres where B cells affinity mature and expand at the central site of disease in rheumatoid arthritis may explain why rheumatoid factors in rheumatoid arthritis develop into auto-aggressive antibodies.     

Juvenile rheumatoid arthritis patients manifest immune reactivity to the mycobacterial 65-kDa heat shock protein, to its 180-188 peptide, and to a partially homologous peptide of the proteoglycan link protein.

Immune reactivity to the 65-kDa mycobacterial heat shock protein (hsp65) has been associated with arthritis in rats and humans. In this report we evaluated patients with juvenile rheumatoid arthritis for such immunity. A high proportion of affected children showed both antibody and T lymphocyte responses to hsp65 and to two related peptides: the nonapeptide 180-188 sequence of hsp65 and a partially homologous peptide of the cartilage proteoglycan link protein. The titer of circulating antibodies was generally higher in patients with clinically active disease. In contrast to the juvenile rheumatoid arthritis patients, patients with adult rheumatoid arthritis tended to have lower responses of their peripheral blood T lymphocytes to the whole hsp65 molecule. Moreover, the adult rheumatoid arthritis patients did not respond to the peptides. Thus, there appear to be immunological differences between juvenile and adult forms of rheumatoid arthritis related to hsp65 reactivity.     

Infliximab

Infliximab is a chimaeric monoclonal antibody which binds to and inhibits the activity of tumour necrosis factor-alpha (TNFalpha), a cytokine which is involved in the development of both Crohn's disease and rheumatoid arthritis. In patients with treatment-resistant Crohn's disease, infliximab was significantly more effective than placebo in the relief of symptoms. 50 to 89% of patients responded to infliximab and most of them also achieved remission. Patients showed signs of relapse 8 to 12 weeks after a single infusion but responded to additional infusions of the drug. Infliximab was also effective in closing the fistulae in 68% of patients with fistulising Crohn's disease; the response rate with placebo was 26%. Infliximab achieved a clinical response in 44 to 81% of patients with refractory rheumatoid arthritis. Following a single infusion, symptom recurrence was evident after 6 to 12 weeks, but subsequent infusions re-established a clinical response. Concurrent methotrexate appeared to prolong the effects of infliximab in this patient group. Anti-infliximab and anti-double-stranded DNA antibodies developed in some patients, particularly those who received multiple infusions of infliximab. Acute adverse events consistent with hypersensitivity occurred in some patients who received multiple infusions of infliximab. Infection occurred slightly more frequently with infliximab than with placebo. CONCLUSIONS: Infliximab appears to be an effective therapy for patients with treatment-resistant or fistulising Crohn's disease or refractory rheumatoid arthritis. The tolerability, long term efficacy and optimal dosage regimen need to be further defined in comparative trials before the full potential of infliximab is realised in these patients.     

Association between polymorphisms in the human chemokine receptor genes CCR2 and CX3CR1 and rheumatoid arthritis

Cell trafficking into the rheumatoid synovium is thought to play an important role in the inflammation seen in rheumatoid arthritis. Chemokine receptors play a central role in this process, and several common variants are known, including the CCR2 variant, CCR2-64I, and two variants of the CX3CR1 gene, V249I and T280M. All three variants result in functional amino acid substitutions. We studied the association of these chemokine receptor variants with susceptibility to and severity of rheumatoid arthritis in two Dutch patient populations; 282 consecutive rheumatoid arthritis patients from a rheumatology outpatient clinic, and a cohort of 101 female rheumatoid arthritis patients, followed closely for a 12-year period, from whom hand and feet X-rays taken at three year intervals were scored and analyzed in this study. Although there was a trend towards increased severity of disease in patients carrying CX3CR1 variants, this was not independent of known risk factors. We found no evidence for a significant independent role for the CCR2 and CX3CR1 variants in the susceptibility to or severity of rheumatoid arthritis.     

Association of tumour necrosis factor-alpha -308 G/A promoter polymorphism with susceptibility and disease profile of rheumatoid arthritis

The objective was to analyze the possible involvement of tumour necrosis factor-alpha (TNF-α) -308 G/A promoter polymorphism in the susceptibility and/or the disease profile of rheumatoid arthritis (RA) in Egyptian patients. TNF-α-308 G/promoter polymorphism detection by amplification refractory mutation system (ARMS) technique was carried out for 122 RA patients and 120 healthy controls. TNF-α-308 G allele/GG homozygous genotype were higher in patients with rheumatoid arthritis than those in control group (P < 0.001, respectively). A statistically significant association was found between the frequency of the A allele and presence of erosion (OR = 3.42, P = 0.015). No associations were found between the distribution of TNF-α-308 G/A alleles/genotypes and age of patients, disease duration, absence of remission, presence of deformity, clinical manifestations of the disease and presence or absence of rheumatoid factor. The positivity of rheumatoid factor was associated with occurrence of erosion (OR = 25.0, P < 0.001). The results of this study demonstrate the association of the TNF-α-308 G allele and GG homozygous genotype with susceptibility to RA and the A allele with the presence of erosion in the Egyptian patients.     

Biobehavioral factors in juvenile rheumatoid arthritis: Implications for research and practice

Juvenile rheumatoid arthritis is the most common connective tissue disease in children. Juvenile rheumatoid arthritis may best be conceptualized as a syndrome of diverse etiologies with three distinct types of disease onset: systemic, poly articular, and pauciarticular. The overall management of juvenile rheumatoid arthritis consists of a multidisciplinary approach to comprehensive care. Biobehavioral factors are delineated into four primary areas: therapeutic adherence, arthritic pain, psychosocial adjustment, and functional independence. To date, relatively little systematic biobehavioral research has been conducted in juvenile rheumatoid arthritis; however, the potential for the interdisciplinary biobehavioral approach to this pediatrie chronic disorder is quite evident.     

HLA-B27 in Rheumatoid Arthritis and Amyloidosis

To study the role of genetically determined immune responsiveness in the pathogenesis of systemic amyloidosis complicating rheumatoid arthritis the HLA antigens were identified in 26 patients with rheumatoid arthritis complicated by secondary amyloidosis, in 44 patients with rheumatoid arthritis, and in 11 patients with secondary amyloidosis of non-rheumatoid origin. Subjects with ankylosing spondylitis, sacroiliitis without peripheral polyarthritis, Reiter's disease, reactive arthritis, erosive osteoarthritis, psoriatic arthropathy, systemic lupus erythematosus or arthritis associated with a gastrointestinal involvement were excluded from the study. Patients with amyloidosis secondary to rheumatoid arthritis had a high frequency of the HLA specificity B27 and of the haplotype likely to bear A2, B27. The association with B27 was closest in the group of male patients with amyloidosis whose rheumatoid arthritis had begun at an early age and who lacked demonstrable rheumatoid factor in serum. These patients may represent a genetically determined subentity of rheumatoid arthritis.     

Association of depression and rheumatoid arthritis

This study assessed the relative strength of the association of physical characteristics and social stresses with a diagnosis of depression in patients with rheumatoid arthritis. Depression and social difficulties were assessed in 74 patients with rheumatoid arthritis by using standardized research interviews. Rheumatoid arthritis activity, damage related to rheumatoid arthritis, and subjective functional disability were assessed with well-validated methods. Twenty-nine patients (39.2%) were depressed. Compared to nondepressed patients, depressed patients had more marked social difficulties related to rheumatoid arthritis (72.4% versus 46.7%, respectively) and more marked social difficulties independent of rheumatoid arthritis (55.2% versus 31.1%, respectively). With logistic regression, social difficulties, independent of rheumatoid arthritis, was the only variable significantly associated with depression. Demographic characteristics and rheumatoid arthritis were not associated with a diagnosis of depression. Recognition by clinicians of the importance of social stresses, independent of disease state, should lead to more appropriate and specific psychological and social treatment of depression in rheumatoid arthritis.     

A novel model of fibroblast-mediated cartilage destruction

In rheumatoid arthritis (RA), fibroblasts have been shown to be crucial for disease progression as well as joint destruction. In the model of human/murine SCID arthritis, synovial explants as well as fibroblasts from human rheumatoid synovial membrane induce destructive arthritis in immunodeficient mice. Hereby, the underlying cartilage destruction is accomplished by murine fibroblasts. Therefore, murine destructive fibroblasts represent a promising tool to investigate destruction of articular cartilage and bone. In this context, a novel destructive murine fibroblast line (LS48) was examined for morphological, ultrastructural, immunological and functional cellular parameters. These cells were injected into knees of SCID mice. Subsequently, the animals were monitored for joint swelling and serological parameters of arthritis by radiological methods. Finally, cartilage destruction was assessed morphologically. Cultured LS48 cells exhibit characteristic features that resemble those of activated synovial fibroblasts in human RA. Expression levels of inducible nitric oxide synthase, interleukin-6, tumour necrosis factor-alpha and matrix metalloproteinases were comparable to those detected in invasive human fibroblasts. The instillation of 5 x 10(5) LS48 cells into the knee joints of SCID mice initiated a rapid progressive process, that caused cartilage destruction within 10 days, and morphological examinations revealed that articular cartilage was infiltrated by the fibroblasts injected previously. In summary, the intra-articular application of LS48 cells represents a rapid and highly reproducible model to investigate the initiation and progression of cartilage destruction in connection with RA therapy and represents an easy-to-handle animal model.