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ID PMID Title PublicationDate abstract
15879156 Gene transfer of tissue inhibitor of metalloproteinases-3 reverses the inhibitory effects 2005 May 15 Apart from counteracting matrix metalloproteinases, tissue inhibitor of metalloproteinases-3 (TIMP-3) has proapoptotic properties. These features have been attributed to the inhibition of metalloproteinases involved in the shedding of cell surface receptors such as the TNFR. However, little is known about effects of TIMP-3 in cells that are not susceptible to apoptosis by TNF-alpha. In this study, we report that gene transfer of TIMP-3 into human rheumatoid arthritis synovial fibroblasts and MRC-5 human fetal lung fibroblasts facilitates apoptosis and completely reverses the apoptosis-inhibiting effects of TNF-alpha. Although TNF-alpha inhibits Fas/CD95-induced apoptosis in untransfected and mock-transfected cells, fibroblasts ectopically expressing TIMP-3 are sensitized most strongly to Fas/CD95-mediated cell death by TNF-alpha. Neither synthetic MMP inhibitors nor glycosylated bioactive TIMP-3 are able to achieve these effects. Gene transfer of TIMP-3 inhibits the TNF-alpha-induced activation of NF-kappaB in rheumatoid arthritis synovial fibroblasts and reduces the up-regulation of soluble Fas/CD95 by TNF-alpha, but has no effects on the cell surface expression of Fas. Collectively, our data demonstrate that intracellularly produced TIMP-3 not only induces apoptosis, but also modulates the apoptosis-inhibiting effects of TNF-alpha in human rheumatoid arthritis synovial fibroblast-like cells. Thus, our findings may stimulate further studies on the therapeutic potential of gene transfer strategies with TIMP-3.
15921325 [Primary study of recombinant immunotoxin IL-18-PE38 in treating rheumatoid arthritis]. 2005 Apr OBJECTIVE: To establish a kind of gene therapy method of rheumatoid arthritis, to construct the interleukin-18-PE38 fusion gene expression vector and to explore the expression of the fusion gene in the chondrocytes and 3T3 cells. METHODS: Interleukin-18-PE38 fusion gene was cleaved from plasmid PRKL459k-IL-18-PE38 by restriction enzyme digestion, then linked with vectors PsecTag2B and transformed into competence bacteria, positive clones were selected and confirmed by restrictive enzyme (EcoRI) digestion assay. The rearrangement plasmid PsecTag2B-IL-18-PE38 was transfected into 3T3 cells and mouse chondrocytes by liposome protocol (experimental group), null vector was used as negative control, and the transient expression was identified by fluorescence Restrictive enzymes digestion analysis revealed that the length of the interleukin-immunocytochemical assay. RESULTS: 18-PE38 fusion gene was 6000 bp. Fluorescence immunocytochemical method showed that fluorescence intensity of the experimental group is strong,while fluorescence intensity of the control group is weak. CONCLUSION: The eukaryotic expression vector PsecTag2B-IL-18-PE38 is established successfully which can be expressed in the 3T3 cells and mouse chondrocytes. Our results lay a foundation for the further investigation for rheumatoid arthritis therapy.
16331767 The effect of apoptosis signal-regulating kinase 1 gene transfer on rat collagen induced a 2005 Dec OBJECTIVE: To examine the apoptosis-inducing effect of apoptosis signal-regulating kinase 1 (ASK1) gene transfer into synovial cells in vitro and in vivo. METHODS: An adenovirus vector was constructed so that a constitutively active form of ASK1 gene (ASK1DeltaN) was expressed in the presence of the Cre recombinase. The ASK1DeltaN and Cre adenovirus vectors were cotransduced into cultured synoviocytes derived from patients with rheumatoid arthritis (RA), and apoptosis was evaluated by TUNEL and Hoechst staining. Collagen induced arthritis (CIA) was induced in 8-week-old male DA rats, and 10 days later the 2 adenovirus vectors were coadministered into the ankle joints of the animals. As indicators of severity of arthritis, swelling of the ankle and articular index (AI) scores were evaluated, while histopathological observation of articular tissue was also performed. RESULTS: In the cultured human RA synoviocytes, overexpression of the ASK1DeltaN significantly reduced cell viability and induced apoptosis. In the CIA rats transduced with the ASK1DeltaN gene, arthritis was significantly promoted in terms of the swelling of the ankle joints and elevation of the AI scores. Histopathological observation also revealed that the constitutively active ASK1 induced massive infiltration of inflammatory cells into the synovial membrane as well as proliferation of synovial fibroblasts. Degeneration of the synovial membrane was not evident. CONCLUSION: Adenoviral transduction of ASK1DeltaN induced apoptosis in RA synoviocytes in vitro, but not in CIA synovium in vivo.
15834055 Implication of interleukin 18 in production of matrix metalloproteinases in articular chon 2005 May OBJECTIVE: To clarify the effect of interleukin (IL) 18 on cartilage degeneration by studying the profile of IL18 receptor (IL18R) on chondrocytes and the direct effect of IL18 on production of matrix metalloproteinases (MMPs), aggrecanases, and tissue inhibitors of metalloproteinases (TIMPs) in articular chondrocytes. METHODS: Monolayer cultured human articular chondrocytes were isolated from non-arthritic subjects and patients with rheumatoid arthritis or osteoarthritis. Gene expression of IL18, IL18Ralpha, IL18Rbeta, MMPs, and aggrecanases was detected by RT-PCR. Protein levels of IL18Ralpha were analysed by flow cytometry. Protein levels of IL18, MMPs, and TIMPs were measured by ELISA. Aggrecanase-2 mRNA expression was quantitatively analysed by real time RT-PCR. Protein levels of signalling molecules were assayed by western blotting. RESULTS: IL18 mRNA was constitutively expressed in chondrocytes, and was enhanced by IL1beta stimulation. Flow cytometric analysis showed that IL1beta, tumour necrosis factor alpha, and IL18 up regulated IL18Ralpha expression levels. The level of IL18Rbeta mRNA was much lower than that of IL18Ralpha, and was slightly up regulated by IL1beta. In chondrocytes responding to IL18, IL18 (1-100 ng/ml) slightly increased the production of MMP-1, MMP-3, and MMP-13, which was blocked by NF-kappaB inhibitor and p38 mitogen activated protein kinase inhibitor. IL18 up regulated mRNA expression of aggrecanase-2, but not aggrecanase-1. IL18 also slightly stimulated TIMP-1 production?through extracellular signal regulated kinase activation. CONCLUSION: IL18 induces production of MMPs from chondrocytes in inflammatory arthritis. Although the direct effect of IL18 on chondrocytes may not be pivotal for the induction of cartilage degeneration, IL18 seems to play some part in the degradation of articular cartilage in arthritis.
15642149 Toll-like receptor downstream signaling. 2005 The family of Toll-like receptors (TLRs) senses conserved structures found in a broad range of pathogens, causing innate immune responses that include the production of inflammatory cytokines, chemokines and interferons. The signal transduction is initiated from the Toll/interleukin-1 receptor (TIR) domain of TLRs after pathogen recognition. Almost all TLRs use a TIR-containing adapter MyD88 to activate a common signaling pathway that results in the activation of NF-kappaB to express cytokine genes relevant to inflammation. Recently, three further TIR-containing adapters have been identified and shown to selectively interact with several TLRs. In particular, activation of the TRIF-dependent pathway confers antiviral responses by inducing anti-viral genes including that encoding interferon-beta. Taken together, these results indicate that the interaction between individual TLRs and the different combinations of adapters directs appropriate responses against distinct pathogens.
16261884 A pilot trial for severe, refractory systemic autoimmune disease with stem cell transplant 2005 Sep OBJECTIVE: To evaluate the feasibility, efficacy, and safety of high dose immunosuppressive therapy (HDIT) and autologous hemopoietic stem cell transplantation (HSCT) with CD34+ cell selection in patients with severe, refractory autoimmune diseases. METHODS: Twenty-six patients with persistent systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), primary Sjögren's syndrome (pSS), or systemic sclerosis (SSc) who had been treated unsuccessfully with conventional treatment were enrolled in the trial in Peking Union Medical College Hospital from September 1999 to June 2004. The patients received HDIT with 200 mg/kg cyclophosphamide followed by an infusion of autologous stem cells that were CD34 selected. Disease activity, adverse effect, hemopoietic and immune reconstitution, and time to recurrence of disease were monitored. RESULTS: Overall treatment related mortality was 7.7% (2/26) with 1 patient died of cytomegalovirus infection and another of severe pneumonia. Relapse occurred in 3 SLE patients (17.6%) in 37, 26, and 19 months posttransplantation respectively, and 1 RA patient in 15 months posttransplantation. SLE Disease Activity Index (SLEDAI) scores of SLE survivors decreased significantly (P < 0.01). RA patients recorded a drop of Disease Activity Score 28 (DAS 28). The pSS patient remained symptoms free up to now, more than 50 months after the transplantation. CONCLUSION: HSCT can be performed relative safely in patients with severe autoimmune disease. Short-term effect of HSCT is promising. However treatment related mortality and relapse were observed in a subset of patients.
16106055 Initiation of an autoimmune response: insights from a transgenic model of rheumatoid arthr 2005 K/BxN mice develop an inflammatory joint disease with many features characteristic of rheumatoid arthritis. This model is based on a T-cell receptor transgene, KRN, that has been shown to recognize both the foreign antigen bovine RNase, and the ubiquitously expressed self antigen, glucose-6-phosphate isomerase (GPI). We have used this model to investigate the initial events that occur during the autoimmune response to GPI. We and others have identified key mediators in the inflammatory response: Fc receptors (FcRs) (in particular FcRIII), the alternative pathway of complement, neutrophils, and mast cells. Using micro position emission tomography, we demonstrated that anti-GPI Immunoglobulin G (IgG) localizes specifically to the joints where arthritis occurs and that this localization is dependent on mast cells, neutrophils, FcRs, and immune complexes. The trigger of arthritis in this model is the KRN T-cell inducing the production of anti-GPI Ig. By overexpressing the ligand for the KRN T-cells in major histocompatibility complex class II-expressing cells, we demonstrated that KRN T-cells were able to escape tolerance induction in the thymus owing to insufficient levels of antigen in the thymus antigen-presenting cells. This allows the KRN T-cells to exit to the periphery, where they provide help to anti-GPI B-cells, inducing the production of arthritogenic Ig. To understand the joint specificity of the disease, we followed the anti-GPI B-cell response that naturally arises in K/BxN mice and showed that, although the GPI antigen is ubiquitously expressed, the anti-GPI B-cell response is focused on the lymph nodes draining the affected joints. Together, these studies have given us a greater understanding of how an autoimmune response is initiated at the level of both the adaptive and innate immune systems and demonstrate the versatility of the K/BxN arthritis model for studying human disease.
16641043 Conversion towards an atherogenic lipid profile in rheumatoid arthritis patients during lo 2006 Mar OBJECTIVES: To analyse the effects of infliximab infusions on serum levels of lipids in patients with rheumatoid arthritis (RA) treated for 2 years. METHODS: Fifty-two patients (41 females and 11 males) with RA undergoing infliximab treatment (3 mg/kg) were consecutively recruited into the study. The mean (+/-SD) age of the patients was 54.6+/-12.5 years and mean disease duration was 14.1+/-8.6 years. Blood was sampled before infusion at baseline, and at 3, 6, 12, 18 and 24 months. Forty-one of the patients were also treated with methotrexate, 13 with other disease-modifying anti-rheumatic drugs (DMARDs) and 28 with prednisolone (<10 mg daily). For comparison, lipid levels were followed for 2 years in 70 consecutively included patients with early RA during treatment with conventional DMARDs. RESULTS: There was an initial increase in plasma levels of cholesterol, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, and LDL/HDL and total/HDL cholesterol ratios. However, after 3 months HDL-cholesterol decreased significantly, followed after 6 months by cholesterol and LDL-cholesterol. The LDL/HDL and total/HDL-cholesterol ratios remained significantly raised. HDL-cholesterol increased and the ratios improved in patients with early RA receiving conventional treatment. The changes over time differed significantly between the patient groups. CONCLUSION: During infliximab infusion a pro-atherogenic lipid profile developed despite reduced inflammatory activity. The long-term decrease in HDL-cholesterol was unexpected considering the known effects of tumour necrosis factor-alpha (TNFalpha).
16096328 Antibodies against cyclic citrullinated peptide (CCP) in psoriatic patients with or withou 2006 Mar OBJECTIVE: To compare the prevalence of anti-CCP antibodies in psoriatic patients with and without joint inflammation, patients with early RA, and controls. METHODS: Anti-CCP antibodies (cut off level 5 U/ml) were measured in 160 patients with psoriatic arthritis (PsA), 146 patients with psoriasis but no arthritic disease, 101 patients with early RA, and 102 healthy controls by ELISA. RESULTS: 11 (7%) patients with PsA, 75 (74%) patients with early RA, 2 (2%) healthy controls (2%), and 1 (0.7%) patient with psoriasis without arthritis had anti-CCP antibodies above the cut off level. The presence of anti-CCP antibodies was not related to radiological changes and/or deformity and functional impairment in PsA. 8/11 patients with PsA and anti-CCP antibodies had a polyarthritic disease, and all fulfilled the ACR criteria for RA at 4 year follow up. Five of these 8 patients also had manifestations such as dactylitis, DIP involvement, radiological changes associated with PsA, and/or enthesitis. In multiple logistic regression analysis with polyarthritis as the dependent variable, anti-CCP antibodies and rheumatoid factor significantly distinguished RA from PsA. CONCLUSIONS: Anti-CCP antibodies were more prevalent in patients with PsA than in patients with psoriasis without arthritis, but less prevalent than in patients with early RA. Patients with PsA positive for anti-CCP antibodies more often had polyarthritic disease, but the presence of anti-CCP antibodies did not relate to radiological changes and/or deformity and functional impairment.
16885604 Interleukin-1 receptor antagonist gene polymorphism in patients with rheumatoid arthritis 2006 Jun BACKGROUND & OBJECTIVES: Interleukin-1 receptor antagonist (IL-1Ra) is a naturally occurring anti-inflammatory molecule that blocks action of IL-1. Polymorphism in IL-1Ra gene intron 2 results in differences in production of IL-1Ra. These polymorphisms are reportedly associated with autoimmune disease susceptibility in different studies. However, such data are lacking from India. We undertook this study to examine the IL-1Ra polymorphism as a susceptibility marker in patients with rheumatoid arthritis (RA). METHODS: DNA samples from 107 patients with RA and 111 healthy controls were used to study genotypes of the IL-1RA gene by PCR. Allelic frequencies and carriage rates were calculated and compared in both the groups. RESULTS: Among the 107 patients with RA, 93 were females and 75 per cent were seropositive for rheumatoid factor. The frequencies of IL-1RA alleles in controls were as follows: Allele 1 (IL- 1RN*1) was 83.33 per cent, IL-1RA allele 2 (IL-1RN*2) was 16.21 per cent and allele 3 (0.46%). In RA patients the allele frequencies were 84.11 per cent for IL-1RN*1, 14.95 per cent for IL- 1RN*2, 0.47 per cent each for IL-1RN*3 and IL-1RN*4. There was no difference in frequency of different alleles between the two groups. However, homozygosity for allele 2 was more frequent in controls (9.91%) as compared to patients (4.67%). INTERPRETATION & CONCLUSION: Our findings indicated that IL-1RA polymorphism was not a susceptibility marker in RA nor did it show any association with seropositivity, Sjögren's syndrome or subcutaneous nodules. Further studies with large sample need to be done to confirm these findings.
16284099 The association between periodontal disease and joint destruction in rheumatoid arthritis 2006 Jul OBJECTIVE: To evaluate a possible association between wrist and periodontal destruction in rheumatoid arthritis, and between periodontal destruction, dry mouth, and labial salivary gland biopsy and the contribution of genetic factors (the shared epitope (SE) and IL1B (+3954) or TNFA (-238 or -308) gene polymorphisms). METHODS: 147 patients with rheumatoid arthritis were enrolled. Periodontal damage was defined according to the Hugoson and Jordan criteria on panoramic dental x rays. Typing for the SE and cytokine polymorphisms was undertaken by enzyme linked oligosorbent assay. Odds ratios (OR), relative risk (RR), and chi2 values were calculated to quantify associations. RESULTS: An association was observed between wrist and periodontal bone destruction (chi2=11.82; p<0.001): 63 patients had both wrist and periodontal destruction, 31 had wrist destruction alone, 20 had periodontal destruction alone, and 33 had no destruction at either site. An association was seen between a positive labial salivary gland biopsy and periodontal bone destruction (RR=2.73 (95% CI, 1.35 to 5.51), p<0.01, n=41) or wrist bone destruction (RR=4.52 (1.96 to 10.45), p<0.001, n=41). The SE was associated with wrist bone destruction (OR=2.5 (1.16 to 5.42), p<0.05) and periodontal bone destruction (OR=2.2 (1.04 to 4.84), p<0.05). No association was found between the selected cytokine polymorphisms and bone destruction. CONCLUSIONS: A strong association was found between wrist and periodontal bone destruction. The destruction risk was further increased in patients with sicca syndrome. The SE appears to be a severity genetic marker for both wrist and periodontal bone destruction.
16014680 Inhibition of c-kit tyrosine kinase by imatinib mesylate induces apoptosis in mast cells i 2005 Aug BACKGROUND: Mast cells have been implicated in the pathogenesis of arthritis, but elucidation of their precise role has been hampered by a lack of efficient and selective inhibitors of their function. OBJECTIVE: To elucidate the role of mast cells in the pathogenesis of rheumatoid arthritis (RA) and to assess whether apoptosis of cultured and synovial tissue mast cells can be induced by inhibiting mast cell growth factor receptor, c-kit tyrosine kinase. METHODS AND RESULTS: Double staining with tumour necrosis factor (TNF) alpha and tryptase antibodies showed the presence of TNFalpha positive mast cells in human rheumatoid synovial tissue. Selective activation of mast cells by anti-IgE resulted in production of TNFalpha in synovial tissue cultures. Inhibition of the c-kit tyrosine kinase with imatinib mesylate (1.0-10 micromol/l) induced profound apoptosis in cultured mast cells as judged by typical apoptotic morphology, increased number of apoptotic nucleosomes, and activation of caspases 8 and 9. Importantly, imatinib also induced apoptosis of mast cells in explant cultures of synovial tissue obtained from patients with RA as judged by a TUNEL assay. Inhibition of c-kit tyrosine kinase was accompanied by significant reduction of TNFalpha production in synovial tissue cultures. CONCLUSION: Mast cells may have a role in the pathogenesis of RA, and inhibition of c-kit may be a new means of inhibiting mast cell activity and of abrogating the contribution of mast cells to synovial inflammation in RA.
16510530 Gene therapy as a therapeutic approach for the treatment of rheumatoid arthritis: innovati 2006 Jun In recent years, significant progress has been made in the treatment of rheumatoid arthritis (RA). In addition to conventional therapy, novel biologicals targeting tumour necrosis factor-alpha have successfully entered the clinic. However, the majority of the patients still has some actively inflamed joints and some patients suffer from side-effects associated with the high systemic dosages needed to achieve therapeutic levels in the joints. In addition, due to of the short half-life of these proteins there is a need for continuous, multiple injections of the recombinant protein. An alternative approach might be the use of gene transfer to deliver therapeutic genes locally at the site of inflammation. Several viral and non-viral vectors are being used in animal models of RA. The first gene therapy trials for RA have already entered the clinic. New vectors inducing long-term and regulated gene expression in specific tissue are under development, resulting in more efficient gene transfer, for example by using distinct serotypes of viral vectors such as adeno-associated virus. This review gives an overview of some promising vectors used in RA research. Furthermore, several therapeutic genes are discussed that could be used for gene therapy in RA patients.
16320316 Regulation of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis: contra 2005 Dec OBJECTIVE: To examine the association between HLA-DRB1 alleles and the production of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) autoantibodies in patients with rheumatoid arthritis (RA). METHODS: We studied 1,723 Caucasian RA patients enrolled in the North American Rheumatoid Arthritis Consortium (NARAC) family cohort and the Study of New Onset Rheumatoid Arthritis (SONORA) cohort. All patients were tested for anti-CCP antibodies (by enzyme-linked immunosorbent assay), RF (by nephelometry), and HLA-DR genotype (by polymerase chain reaction and sequence-specific oligonucleotide hybridization). RESULTS: When controlled for the presence of RF, anti-CCP positivity was strongly associated with the HLA-DRB1 shared epitope (SE). In RF+ patients, the presence of the SE was very significantly associated with anti-CCP positivity, with an odds ratio (OR) of 5.8 and a 95% confidence interval (95% CI) of 4.1-8.3. This relationship was also seen in RF- patients (OR 3.1 [95% CI 1.8-5.3]). In contrast, RF positivity was not significantly associated with presence of the SE independently of anti-CCP antibodies. Strikingly, HLA-DRB1*03 was strongly associated with reduced anti-CCP titers, even after controlling for the presence of the SE and restricting the analysis to anti-CCP+ patients. HLA-DR3 was also associated with anti-CCP- RA in our population. CONCLUSION: The HLA-DRB1 SE is strongly associated with the production of anti-CCP antibodies, but not RF. In contrast, HLA-DR3 alleles are associated with anti-CCP- disease and with lower levels of anti-CCP antibodies, even when controlling for the SE. These data emphasize the complexity of the genetic effects of the major histocompatibility complex on the RA phenotype.
16951351 Crystallographic structure of a rheumatoid arthritis MHC susceptibility allele, HLA-DR1 (D 2006 Sep 15 The expression of HLA-DR1 (DRB1*0101) is associated with an enhanced risk for developing rheumatoid arthritis (RA). To study its function, we have solved the three-dimensional structure of HLA-DR1 complexed with a candidate RA autoantigen, the human type II collagen peptide CII (259-273). Based on these structural data, the CII peptide is anchored by Phe263 at the P1 position and Glu266 at P4. Surprisingly, the Lys at the P2 position appears to play a dual role by participating in peptide binding via interactions with DRB1-His81 and Asn82, and TCR interaction, based on functional assays. The CII peptide is also anchored by the P4 Glu266 residue through an ionic interaction with DRB1-Arg71 and Glu28. Participation of DRB1-Arg71 is significant because it is part of the shared epitope expressed by DR alleles associated with RA susceptibility. Potential anchor residues at P6 and P9 of the CII peptide are both Gly, and the lack of side chains at these positions appears to result in both a narrower binding groove with the peptide protruding out of the groove at this end of the DR1 molecule. From the TCR perspective, the P2-Lys264, P5-Arg267, and P8-Lys270 residues are all oriented away from the binding groove and collectively represent a positive charged interface for CII-specific TCR binding. Comparison of the DR1-CII structure to a DR1-hemagglutinin peptide structure revealed that the binding of these two peptides generates significantly different interfaces for the interaction with their respective Ag-specific TCRs.
16284094 Trichostatin A sensitises rheumatoid arthritis synovial fibroblasts for TRAIL-induced apop 2006 Jul BACKGROUND: Histone acetylation/deacetylation has a critical role in the regulation of transcription by altering the chromatin structure. OBJECTIVE: To analyse the effect of trichostatin A (TSA), a streptomyces metabolite which specifically inhibits mammalian histone deacetylases, on TRAIL-induced apoptosis of rheumatoid arthritis synovial fibroblasts (RASF). METHODS: Apoptotic cells were detected after co-treatment of RASF with TRAIL (200 ng/ml) and TSA (0.5, 1, and 2 micromol/l) by flow cytometry using propidium iodide/annexin-V-FITC staining. Cell proliferation was assessed using the MTS proliferation test. Induction of the cell cycle inhibitor p21Waf/Cip1 by TSA was analysed by western blot. Expression of the TRAIL receptor-2 (DR5) on the cell surface of RASF was analysed by flow cytometry. Levels of soluble TRAIL were measured in synovial fluid of patients with RA and osteoarthritis (OA) by ELISA. RESULTS: Co-treatment of the cells with TSA and TRAIL induced cell death in a synergistic and dose dependent manner, whereas TRAIL and TSA alone had no effect or only a modest effect. RASF express DR5 (TRAIL receptor 2), but treatment of the cells with TSA for 24 hours did not change the expression level of DR5, as it is shown for cancer cells. TSA induced cell cycle arrest in RASF through up regulation of p21Waf1/Cip1. Levels of soluble TRAIL were significantly higher in RA than in OA synovial fluids. CONCLUSION: Because TSA sensitises RASF for TRAIL-induced apoptosis, it is concluded that TSA discloses sensitive sites in the cascade of TRAIL signalling and may represent a new principle for the treatment of RA.
16125248 Natural resistance-associated macrophage protein 1 gene polymorphisms in rheumatoid arthri 2006 Jan 15 OBJECTIVES: To investigate the association of natural resistance-associated macrophage protein 1 gene (NRAMP1) polymorphisms with rheumatoid arthritis (RA) in Taiwan. METHODS: NRAMP1 polymorphisms were determined from 113 RA patients and 74 healthy controls using the polymerase chain reaction/restriction fragment length polymorphism method. RESULTS: The genotype frequencies of NRAMP1 823 C/C, 1703G/G (543D/D), and 1729+55 del 4 TGTG+/+ (244/244) were significantly higher in patients with RA than in controls. Similar findings were also evident in allele frequencies and allele carriage frequencies of 823C, 1703G (543D), and 1729+55 del 4 TGTG+ (244). The associations of these polymorphisms with RA were independent of HLA-DR4. Linkage disequilibria could be found between 823C and 1703G, and between 1703G and 1729+55 del 4 TGTG+. The estimated haplotype frequency of NRAMP1 823C/1703G/1729+55 del 4 TGTG+ was significantly increased in RA patients compared with controls. We also found that patients with 823 C/C had a significantly lower prevalence of rheumatoid nodule than those without 823 C/C. CONCLUSION: NRAMP1 823C, 1703G (543D), and 1729+55 del 4 TGTG+ (244) are precipitating factors for the development of RA in Taiwan. The estimated NRAMP1 823C/1703G/1729+del 4 TGTG+ haplotype is associated with susceptibility to RA. NRAMP1 823 C/C prevents the development of rheumatoid nodule in RA patients.
15932464 Power Doppler 'blanching' after the application of transducer pressure. 2005 Jun The aim of this study was to determine if transducer pressure modifies power Doppler assessments of rheumatoid arthritis synovium at the metacarpophalangeal joints and metatarsophalangeal joints. Five rheumatoid arthritis patients of varying degrees of 'disease activity' and damage were assessed with power Doppler ultrasound scanning of the dominant hand second to fifth metacarpophalangeal joints. Two rheumatoid arthritis patients had their dominant foot first to fifth metatarsophalangeal joints assessed with power Doppler ultrasound. Ultrasonography was performed with a high frequency transducer (14 MHz) with a colour mode frequency of 10 Mhz, and a standard colour box and gain. In the joint that showed the highest power Doppler signal, an image was made. A further image was taken after transducer pressure was applied. In all patients, there was increased flow to at least one joint. After pressure was applied, power Doppler signal intensity markedly reduced in all images and in some there was no recordable power Doppler signal. Increased transducer pressure can result in a marked reduction or obliteration in power Doppler signal. This power Doppler 'blanching' shows the need for further studies to evaluate sources of error and standardization before power Doppler ultrasound becomes a routine measure of 'disease activity' in rheumatoid arthritis.
16126991 Increased spontaneous apoptosis of CD4+CD25+ T cells in patients with active rheumatoid ar 2005 Jun Increased secretion of tumor necrosis factor-alpha (TNF-alpha), along with interleukin-1 (IL-1) and interleukin-6 (IL-6), is important in the pathogenesis of rheumatoid arthritis (RA). T regulatory CD4(+)CD25(+) cells play a role in maintaining self-tolerance by downregulating Th1-induced proinflammation. This function has been found to be altered in active RA, whereas anti-TNF-alpha therapy has been found to improve the suppressive abilities of these cells. Our objectives were to investigate whether T regulatory cells in patients with active RA display a higher sensitivity to spontaneous apoptosis than in normals, and to look into the potential of infliximab (anti-TNF-alpha therapy) to reduce the sensitivity of these cells to spontaneous apoptosis. Seventeen patients suffering from active RA, having failed multiple disease-modifying antirheumatic drug (DMARD) therapies, were treated with infliximab. Spontaneous apoptosis (as detected by annexin V binding) was determined in all patients and compared with a group of normal individuals at baseline and after three months on infliximab treatment. Peripheral blood mononuclear cells were incubated in 24-well plates at 1 x 10(6) cells/mL for 48 hours. Annexin V binding on CD4(+)CD25(+) was assessed using three-color assay by flow cytometry. Prior to infliximab initiation, spontaneous apoptosis of T regulatory cells from active RA patients was found to be increased in comparison with controls (26 +/- 4.2% vs. 19.8 +/- 4.8%, respectively; P = 0.01). Three months later (while still on infliximab) spontaneous apoptosis was comparable in the two groups (20.7 +/- 5.2% vs. 20.9 +/- 3.4%; P 5 0.8). The absolute number of CD4(+)CD25(+) cells/mL in the peripheral blood at baseline was reduced in 11 out of 17 active RA patients when compared with that of the control group (24 +/- 7 vs. 32 +/- 11, respectively; P = 0.02). Following anti-TNF-alpha therapy, CD4(+)CD25(+) cell counts of patients were equivalent to those of normals. The alteration and reversal in both spontaneous apoptosis and cell count of T regulatory cells was found to correlate with RA disease activity. CD4(+)CD25(+) T regulatory cells display increased proclivity to undergo spontaneous apoptosis in active RA. Alterations in CD4(+)CD25(+) cell apoptosis and cell count were found to correlate with RA disease activity. Reversal of these deviations from normal was documented in association with the beneficial outcome of infliximab therapy.
15958758 Infliximab treatment reduces complement activation in patients with rheumatoid arthritis. 2005 Jul BACKGROUND: Tumour necrosis factor (TNF) blocking agents decrease C reactive protein (CRP) levels in rheumatoid arthritis (RA). It has been shown that CRP may contribute to complement activation in RA. OBJECTIVE: To assess the effect of intravenous infliximab treatment on complement activation, especially that mediated by CRP, in RA. METHODS: 35 patients with active RA (28 joint count Disease Activity Score (DAS28) >4.4) were treated with intravenous injections of infliximab (3 mg/kg, at weeks 0, 2, 6, 14, and 22). Clinical response and plasma levels of complement activation products, of CRP and of CRP-complement complexes, which are specific markers for CRP mediated complement activation, were assessed at the indicated time points up to 22 weeks. The relationship between CRP and CRP-complement complexes was analysed by paired t test between two time points and by generalised estimated equation, to test differences of variables over time. RESULTS: At 2 weeks after the first dose, infliximab significantly reduced overall C3 and C4 activation and plasma levels of CRP and CRP-complement complexes were also significantly reduced at this time point. The effects of infliximab on CRP and complement continued throughout the observation period and were more pronounced in patients with a good response to infliximab treatment. CONCLUSION: Treatment with infliximab decreases plasma levels of CRP and CRP dependent complement activation products and concomitantly may reduce complement activation in RA. Complement activation may be among the effector mechanisms of TNF in RA.