Rheumatoid Arthritis: El-Gabalawy H

El-Gabalawy H. · University of Manitoba, Manitoba, Canada. · Best Pract Res Clin Rheumatol. · Pubmed #19233045 No free full text.

Abstract: Rheumatoid arthritis (RA) is a systemic autoimmune disorder based in the synovium of peripheral joints. Rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) are autoantibodies detectable in the majority of patients, with the latter being highly specific for RA. Retrospective studies utilizing preclinical serum samples have demonstrated that RF and ACPAs are detectable in the serum of RA patients months to years before disease onset. Moreover, a close association between ACPAs, smoking, and disease-predisposing HLA-DRB1 alleles has been identified, suggesting that these risk factors may converge to precipitate autoantibody-positive RA. Animal models of RA have added considerable information regarding the immune events that precede joint inflammation. These models have demonstrated that autoantibodies to ubiquitous antigens can directly precipitate chronic organ-specific inflammation centred in the joint. Furthermore, it has recently been possible to demonstrate a role for ACPAs in the animal models of RA. The major challenge currently is to develop a robust predictive model for RA onset, identifying the factors that serve to initiate, amplify, and mature the immune responses towards citrullinated autoantigens. Recent data from a high-risk population of RA family members indicate that the nature and specificity of the ACPA response in healthy individuals differs considerably from that in RA patients, and support the concept that this autoimmune response evolves over time and leads to the onset of clinically detectable synovitis. Ultimately, the availability of data from prospective studies of RA onset will allow for novel strategies that can potentially prevent disease in high-risk individuals.

Keeling SO, Landewe R, van der Heijde D, Bathon J, Boers M, Garnero P, Geusens P, El-Gabalawy H, Inman RD, Kraus VB, Kvien TK, Mease PJ, Ostergaard M, Ritchlin C, Syversen SW, Maksymowych WP. · Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. · J Rheumatol. · Pubmed #17343310 No free full text.

Abstract: OBJECTIVE: A list of 14 criteria for guiding the validation of a soluble biomarker as reflecting structural damage endpoints in rheumatoid arthritis (RA) clinical trials was drafted by an international working group after a Delphi consensus exercise. C-reactive protein (CRP), a soluble biomarker extensively studied in RA, was then used to test these criteria. Our objectives were: (1) To assess the strength of evidence in support of CRP as a soluble biomarker reflecting structural damage in RA according to the draft validation criteria. (2) To assess the strength of recommendation for inclusion of individual criteria in the draft set. METHODS: A systematic literature review was conducted to elicit evidence in support of each specific criterion composing the 14-criteria draft set. A summary of the key literature findings per criterion was presented to both the working group and to participants in a special interest soluble biomarker group at OMERACT 8. Participants at OMERACT 8 were asked to rate the strength of evidence and the strength of the recommendation in support of each individual criterion on a 0-10 numerical rating scale. Working group members not present at OMERACT voted by a Web-based survey. RESULTS: Minimal data were extracted from the literature pertaining to those criteria listed under the category of truth. Ratings for strength of evidence were moderate to low (< 7) for CRP as a biomarker reflecting structural damage in RA; this was true for all criteria except those listed under the category of feasibility and 2 listed under the category of discrimination pertaining to assay reproducibility and evidence regarding sources of variability. Ratings for strength of recommendation for inclusion of each of the 14 criteria in the draft set were high (> 7) except for those criteria listed under the category of truth. CONCLUSION: The draft criteria serve as a useful template in the evaluation of the strength of evidence in support of a particular soluble biomarker as reflecting structural damage in RA.

McCulloch CA, Downey GP, El-Gabalawy H. · CIHR Group in Matrix Dynamics, University of Toronto, Toronto, Canada M5S 3E2. · Nat Rev Drug Discov. · Pubmed #17016427 No free full text.

Abstract: Therapeutically controlling inflammation is essential for the clinical management of many high-prevalence human diseases. Drugs that block the pro-inflammatory cytokines tumour-necrosis factor-alpha and interleukin-1 (IL-1) can improve outcomes for rheumatoid arthritis and other inflammatory diseases but many patients remain refractory to treatment. Here we explore the need for developing new types of anti-inflammatory drugs and the emergence of novel drug targets based on the clustering of IL-1 receptors into multi-protein aggregates associated with cell adhesions. Interference with receptor aggregation into multi-protein complexes effectively abrogates IL-1 signalling. The exploration of the crucial molecules required for receptor clustering, and therefore signal transduction, offers new targets and scope for anti-inflammatory drug development.

El-Gabalawy H. · Arthritis and Rheumatism Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA. · Arthritis Res. · Pubmed #11094411 links to  free full text

This publication has no abstract.

Mease PJ, Hobbs K, Chalmers A, El-Gabalawy H, Bookman A, Keystone E, Furst DE, Anklesaria P, Heald AE. · Seattle Rheumatology Associates/Swedish Medical Center Research, Seattle, Washington, USA. · Ann Rheum Dis. · Pubmed #18678578 No free full text.

Abstract: OBJECTIVE: To examine the safety and tolerability of a single intra-articular injection of rAAV2-TNFR:Fc, an adenoassociated virus serotype 2 vector containing the cDNA for the human tumour necrosis factor-immunoglobulin Fc fusion gene (tgAAC94), in subjects with inflammatory arthritis. METHODS: In a double-blind, placebo-controlled, phase 1, dose-escalation study, 15 subjects with inflammatory arthritis (14 with rheumatoid arthritis and 1 with ankylosing spondylitis) not receiving tumour necrosis factor alpha (TNFalpha) inhibitors with persistent moderate (grade 2) or severe (grade 3) swelling in a target joint due to inflammatory arthritis received a single intra-articular injection of rAAV2-TNFR:Fc at 1 x 10(10) (n = 5) or 1 x 10(11) (n = 6) DNase resistant particles per ml joint volume or placebo (n = 4) into a knee (n = 14) or ankle (n = 1). Safety was assessed through adverse event monitoring. As a secondary objective, changes in injected joint tenderness and swelling scores, each measured on a four-point scale, were evaluated. RESULTS: Intra-articular injections of rAAV2-TNFR:Fc were well tolerated with no major safety issues. One event, mild knee pruritis, was considered probably related. Synovial fluid TNFR:Fc protein was not detected (nor expected) at the doses used. At 12 weeks after injection, a two-point decrease in swelling was noted in 2/11 and 2/4 subjects injected with rAAV2-TNFR:Fc and placebo, respectively. CONCLUSION: A single dose of intra-articular rAAV2-TNFR:Fc appears to be safe and well tolerated in subjects without concurrent systemic TNFalpha antagonist use. It is thus feasible to proceed with larger trials to further test the safety and efficacy of local TNFR:Fc gene transfer as a therapeutic modality for patients with inflammatory arthritis.

Harris ML, Darrah E, Lam GK, Bartlett SJ, Giles JT, Grant AV, Gao P, Scott WW, El-Gabalawy H, Casciola-Rosen L, Barnes KC, Bathon JM, Rosen A. · Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA. · Arthritis Rheum. · Pubmed #18576335 links to  free full text

Abstract: OBJECTIVE: Protein citrullination is an important posttranslational modification recognized by rheumatoid arthritis (RA)-specific autoantibodies. One of the citrullinating enzymes, peptidyl arginine deiminase type 4 (PAD-4), is genetically associated with development of RA in some populations, although the mechanism(s) mediating this effect are not yet clear. There have been descriptions of anti-PAD-4 autoantibodies in different rheumatic diseases. This study was undertaken to investigate whether anti-PAD-4 antibodies are specific to RA, are associated with disease phenotype or severity, and whether PAD-4 polymorphisms influence the anti-PAD-4 autoantibody response. METHODS: Sera from patients with established RA, patients with other rheumatic diseases, and healthy adults were assayed for anti-PAD-4 autoantibodies by immunoprecipitation of in vitro-translated PAD-4. The epitope(s) recognized by PAD-4 autoantibodies were mapped using various PAD-4 truncations. PAD-4 genotyping was performed on RA patients with the TaqMan assay. Joint erosions were scored from hand and foot radiographs using the Sharp/van der Heijde method. RESULTS: PAD-4 autoantibodies were found in 36-42% of RA patients, and were very infrequent in controls. Recognition by anti-PAD-4 autoantibodies required the 119 N-terminal amino acids, which encompass the 3 nonsynonymous polymorphisms associated with disease susceptibility. Strikingly, the anti-PAD-4 immune response was associated with the RA susceptibility haplotype of PADI4. Anti-PAD-4 antibodies were associated with more severe joint destruction in RA. CONCLUSION: Our findings indicate that anti-PAD-4 antibodies are specific markers of RA, independently associated with more severe disease, suggesting that an anti-PAD-4 immune response may be involved in pathways of joint damage in this disease. Polymorphisms in the PADI4 gene influence the immune response to the PAD-4 protein, potentially contributing to disease propagation.

Weiler T, Du Q, Krokhin O, Ens W, Standing K, El-Gabalawy H, Wilkins JA. · Department of Internal Medicine and Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, 715 McDermot Avenue, Winnipeg, Manitoba, R3E 3P4, Canada. · Arthritis Res Ther. · Pubmed #17362502 links to  free full text

Abstract: Joint inflammation and destruction have been linked to the deregulation of the highly synthetic fibroblast-like synoviocytes (FLSs), and much of our current understanding of the mechanisms that underlie synovitis has been collected from studies of FLSs. During a proteomic analysis of FLS cells, we identified a novel protein, c19orf10 (chromosome 19 open reading frame 10), that was produced in significant amounts by these cells. The present study provides a partial characterization of c19orf10 in FLSs, synovial fluid, and the synovium. Murine monoclonal and chicken polyclonal antibodies were produced against recombinant human c19orf10 protein and used to examine the distribution of c19orf10 in cultured FLSs and in synovial tissue sections from patients with rheumatoid arthritis or osteoarthritis. The intracellular staining pattern of c19orf10 is consistent with localization in the endoplasmic reticulum/Golgi distribution. Sections of rheumatoid arthritis and osteoarthritis synovia expressed similar patterns of c19orf10 distribution with perivascular and synovial lining staining. Double-staining in situ analysis suggests that fibroblast-like synovial cells produced c19orf10, whereas macrophages, B cells, or T cells produced little or none of this protein. There is evidence of secretion into the vascular space and the extracellular matrix surrounding the synovial lining. A competitive enzyme-linked immunosorbent assay confirmed the presence of microgram levels of c19orf10 in the synovial fluids of patients with one of various arthropathies. Collectively, these results suggest that c19orf10 is an FLS-derived protein that is secreted into the synovial fluid. However, the significance of this protein in synovial biology remains to be determined. The absence of known structural motifs or domains and its relatively late evolutionary appearance raise interesting questions about its function.

Maksymowych WP, Landewe R, Boers M, Garnero P, Geusens P, El-Gabalawy H, Heinegard D, Kraus VB, Krause V, Lohmander S, Matyas J, Saxne T, van der Heijde D. · Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. · J Rheumatol. · Pubmed #17343311 No free full text.

Abstract: OBJECTIVE: Recent work has shown that several soluble biomarkers, detectable in peripheral blood, synovial fluid, and/or urine, reflect remodeling of joint tissues and may therefore constitute outcome measures that reflect joint damage. Consequently, it is now desirable to begin the process of developing criteria for validation of a soluble biomarker as an outcome measure reflecting structural damage progression in trials of disease-modifying therapies for rheumatoid arthritis (RA) and spondyloarthritis (SpA). Our objective was to develop validation criteria for a soluble biomarker to be regarded as a valid biomarker reflecting radiological endpoints in RA and SpA clinical trials. METHODS: A special interest group was established comprising investigators with expertise in soluble biomarker assay development as well as in outcomes research. This project was initiated by means of a Delphi consensus exercise. A list of draft criteria was first generated following a review of a US National Institutes of Health (NIH) 2000 white paper (available at: http://www.niams.nih.gov/ne/oi/ oabiomarwhipap.htm) that focused on biomarkers in OA, and these were organized under subject headings relevant to the OMERACT filter: truth, discrimination, and feasibility. Additional criteria were solicited from the working group. This was followed by 3 rounds of voting. RESULTS: A list of 31 criteria was generated prior to voting. The first 2 rounds of voting resulted in cumulative agreement that 19 criteria be retained and 4 discarded, while discrepancies were recorded for 8 criteria. In the third round of voting, cumulative agreement was achieved to retain 5 of the 8 discrepant criteria, so that the final list included 24 criteria. CONCLUSION: A draft set of criteria for validation of a soluble biomarker to be regarded as reflecting radiological damage endpoints in clinical trials has been proposed on the basis of consensus.

Brar A, Hiebert T, El-Gabalawy H. · University of Manitoba, Winnipeg, Canada. · Nat Clin Pract Rheumatol. · Pubmed #17334334 No free full text.

This publication has no abstract.

Dasuri K, Antonovici M, Chen K, Wong K, Standing K, Ens W, El-Gabalawy H, Wilkins JA. · Rheumatic Diseases Research Laboratory, University of Manitoba, Winnipeg, Canada. · Arthritis Res Ther. · Pubmed #15059280 links to  free full text

Abstract: The present studies were initiated to determine the protein expression patterns of fibroblast-like synovial (FLS) cells derived from the synovia of rheumatoid arthritis patients. The cellular proteins were separated by two-dimensional polyacrylamide gel electrophoresis and the in-gel digested proteins were analyzed by matrix-assisted laser desorption ionization mass spectrometry. A total of 368 spots were examined and 254 identifications were made. The studies identified a number of proteins that have been implicated in the normal or pathological FLS function (e.g. uridine diphosphoglucose dehydrogenase, galectin 1 and galectin 3) or that have been characterized as potential autoantigens in rheumatoid arthritis (e.g. BiP, colligin, HC gp-39). A novel uncharacterized protein product of chromosome 19 open reading frame 10 was also detected as an apparently major component of FLS cells. These results demonstrate the utility of high-content proteomic approaches in the analysis of FLS composition.

Groh V, Bruhl A, El-Gabalawy H, Nelson JL, Spies T. · Fred Hutchinson Cancer Research Center, Clinical Research Division, Seattle, WA 98109, USA. · Proc Natl Acad Sci U S A. · Pubmed #12878725 links to  free full text

Abstract: Effector T cell responses can be modulated by competing positive or negative signals transduced by natural killer (NK) cell receptors. This raises the possibility that dominant T cell stimulation might promote autoimmune reactions. In rheumatoid arthritis (RA), the severity of autoimmune and inflammatory joint disease correlates with large numbers of CD4+CD28- T cells, which are scarce in healthy individuals. For poorly defined reasons, these T cells are autoreactive, implying that they may contribute to disease manifestations. CD4+CD28- T cells in peripheral blood and synovial tissue of RA patients were found to express NKG2D, a costimulatory receptor that is absent on normal CD4 T cells. NKG2D was induced by tumor necrosis factor alpha and IL-15, which are abundant in inflamed synovia and RA patient sera. RA synoviocytes aberrantly expressed the stress-inducible MIC ligands of NKG2D, which stimulated autologous CD4+CD28- T cell cytokine and proliferative responses. Peripheral blood serum samples of RA patients contained substantial amounts of synoviocyte-derived soluble MICA, which failed to induce down-modulation of NKG2D because of the opposing activity of tumor necrosis factor alpha and IL-15. These results suggest that a profound dysregulation of NKG2D and its MIC ligands may cause autoreactive T cell stimulation, thus promoting the self-perpetuating pathology in RA and possibly other autoimmune diseases.

Matsumoto I, Lee DM, Goldbach-Mansky R, Sumida T, Hitchon CA, Schur PH, Anderson RJ, Coblyn JS, Weinblatt ME, Brenner M, Duclos B, Pasquali JL, El-Gabalawy H, Mathis D, Benoist C. · Joslin Diabetes Center and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA. · Arthritis Rheum. · Pubmed #12687536 links to  free full text

Abstract: OBJECTIVE: Arthritis in the K/BxN mouse model results from pathogenic immunoglobulins that recognize glucose-6-phosphate isomerase (GPI), a glycolytic enzyme residing in the cytoplasm of all cells. Antibodies directed against GPI can, alone, transfer arthritis to healthy recipients. Previous experiments have revealed significant titers of anti-GPI antibodies in the serum of many patients with rheumatoid arthritis (RA). We evaluated the generality of these observations in cohorts of patients with 12 different arthritic and chronic autoimmune diseases and in population-matched healthy control subjects. METHODS: Anti-GPI antibodies were assayed in 811 individual serum samples by enzyme-linked immunosorbent assay with 2 forms of GPI, recombinant and native. Results were confirmed by immunoblotting. RESULTS: Several patients had significantly elevated anti-GPI antibody titers, but without the prevalence or the specificity reported previously. Only 15% of RA patients had anti-GPI antibodies (range 12-29% in different cohorts), with a higher prevalence in patients with active disease. Psoriatic arthritis, undifferentiated arthritis, and spondylarthropathy patients also displayed anti-GPI antibodies at similar frequencies (12-25%). Similar titers were detected in a proportion (5-10%) of control subjects or patients with Crohn's disease or sarcoidosis. Very high titers were found in rare cases of RA and systemic lupus erythematosus. CONCLUSION: No disease-specific pattern of antibody positivity to GPI was apparent. While the antibody-mediated mechanism at play in the mouse model may exemplify a generic mechanism for some forms of arthritis in humans, GPI itself does not appear to be a target common to the majority of RA patients.

Hitchon C, Wong K, Ma G, Reed J, Lyttle D, El-Gabalawy H. · Rheumatic Disease Research Laboratory, University of Manitoba, 800 Sherbrook Street, Winnipeg, Manitoba, Canada R3A 1M4. · Arthritis Rheum. · Pubmed #12384916 links to  free full text

Abstract: OBJECTIVE: Stromal cell-derived factor 1 (SDF-1; or, CXCL12) is a potent chemotactic and angiogenic factor that has been proposed to play a role in the recruitment of lymphocytes into rheumatoid arthritis (RA) synovium. We tested the hypothesis that synovial SDF-1 expression is regulated by cytokine and hypoxic stimulation, the latter being mediated by hypoxia-inducible factor 1alpha (HIF-1alpha). These factors regulate the expression of vascular endothelial growth factor (VEGF), itself an important angiogenic mediator. METHODS: RA and osteoarthritic synovial fibroblasts and whole tissue explants were cultured under normoxic or hypoxic (1% O(2)) conditions for up to 72 hours in the presence or absence of interleukin-1beta (IL-1beta), tumor necrosis factor (TNF), or transforming growth factor beta (TGFbeta). Expression of HIF-1alpha, VEGF, and SDF-1 was detected in synovial tissue and cells by immunohistochemistry and Western blotting. VEGF and SDF-1 expression by cultured synovial fibroblasts was evaluated by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: Immunohistochemistry revealed the presence of HIF-1alpha, VEGF, and SDF-1 in RA synovium. Patchy expression of HIF-1alpha was detected primarily in the synovial lining and sublining areas; expression in synovial fibroblasts and in the lining cells of whole synovial tissue explants was markedly augmented by hypoxic culture conditions. Hypoxia enhanced the expression of VEGF and SDF-1 messenger RNA in synovial fibroblasts. The production of VEGF and SDF-1 protein by synovial fibroblasts was augmented by 50% and 132%, respectively, after 24 hours of hypoxia. VEGF production was potently induced by TGFbeta, and to a lesser extent by IL-1beta and TNF, and was further augmented by hypoxia. In contrast, none of the tested cytokines induced SDF-1 production. CONCLUSION: As with VEGF, SDF-1 expression is induced by hypoxia; however, cytokines induce VEGF but not SDF-1. Hypoxic conditions in RA synovium, which are likely to be transient and episodic, may contribute to the persistence of synovitis by inducing VEGF and SDF-1.

Brennan MT, Pillemer SR, Goldbach-Mansky R, El-Gabalawy H, Schumacher HR, Fox PC. · Clinical Research Core, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA. · Clin Exp Rheumatol. · Pubmed #11491501 No free full text.

Abstract: OBJECTIVE: To investigate the frequency of sialadenitis on lip biopsy in patients with synovitis of recent onset (ES), and see how sialadenitis relates to clinical and laborator findings of ES. METHODS: Joint involvement, laboratory measures and biopsies of the minor salivary glands were evaluated in 10 ES patients. Diagnosis at a one-year follow-up exam was noted. RESULTS: Six ES patients (60%) had a positive lip biopsy (mononuclear cell focus score greater than 1). ES patients with a positive lip biopsy presented with oligoarthritis, while ES patients with a negative lip biopsy had a more polyarticular presentation. No differences in laboratory measures between patients with a positive and negative lip biopsy were present. Seven ES patients had a diagnosis of rheumatoid arthritis and three had undifferentiated arthritis at the end of one year. CONCLUSION: ES patients had a higher than expected frequency offocal sialadenitis.

Gérard HC, Wang Z, Wang GF, El-Gabalawy H, Goldbach-Mansky R, Li Y, Majeed W, Zhang H, Ngai N, Hudson AP, Schumacher HR. · Wayne State University School of Medicine, Detroit, Michigan 48201, USA. · Arthritis Rheum. · Pubmed #11465721 links to  free full text

Abstract: OBJECTIVE: We and others have reported the presence of Chlamydia and other bacterial species in joint specimens from patients with reactive arthritis (ReA). The present study was conducted to investigate whether bacteria other than those specified by diagnostic criteria for ReA could be identified in synovial fluid (SF) or tissue from patients with various arthritides, and whether the presence of such organisms corresponds to particular clinical characteristics in any patient set or subset. METHODS: DNA in synovial biopsy samples and SF obtained from 237 patients with various arthritides, including ReA, rheumatoid arthritis, and undifferentiated oligoarthritis, was assayed by polymerase chain reaction (PCR) using "panbacterial" primers; we chose only samples known to be PCR negative for Chlamydia, Borrelia, and Mycoplasma species. PCR products were cloned, and cloned amplicons from each sample were sequenced; DNA sequences were compared against all others in GenBank for identification of bacterial species involved. RESULTS: Ten percent of patient samples were PCR positive in panbacterial screening assays. Bacterial species identified belonged to the genera Neisseria, Acinetobacter, Moraxella, Salmonella, Pseudomonas, and others. Thirty-five percent of PCR-positive patients showed the presence of DNA from more than a single bacterial species in synovium; overall, however, we could identify no clear relationship between specific single or multiple bacterial species in the synovium and any general clinical characteristics of any individual or group of patients. CONCLUSION: This analysis provides the first systematic attempt to relate bacterial nucleic acids in the synovium to clinical characteristics, joint findings, and outcomes. Many patients with arthritis have bacterial DNA in the joint, and, in some cases, DNA from more than a single species is present. However, except for 1 case of a control patient with staphylococcal septic arthritis, it is not clear from the present study whether the synovial presence of such organisms is related to disease pathogenesis or evolution in any or all cases.

Gérard HC, Schumacher HR, El-Gabalawy H, Goldbach-Mansky R, Hudson AP. · Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201, USA. · Microb Pathog. · Pubmed #10873487 No free full text.

Abstract: We demonstrated that chromosomal DNA from Chlamydia pneumoniae is present in synovial tissue in at least some patients with reactive arthritis/Reiter's syndrome and other arthritides. Here, we provide initial molecular evidence that the bacterium is viable and metabolically active when present in the synovium. We used reverse transcription-polymerase chain reaction (RT-PCR) assays targeting primary transcripts from the chlamydial rRNA operons, and mRNA from several C. pneumoniae genes (hsp60, ompA, KDO transferase, Mr=76000 protein), to analyse RNA preparations from synovial tissue of 10 patients with various forms of arthritis; each patient was known to be PCR-positive for C. pneumoniae DNA in synovium prior to RT-PCR assays. Two PCR-negative patients served as controls for RT-PCR assays. In the 10 patients PCR-positive for C. pneumoniae DNA, RT-PCR assays targeting primary transcripts from the rRNA operons of the organism showed that these molecules were present in each sample, as were transcripts from the bacterial hsp60 gene. Assays targeting mRNAs from the Mr=76000 protein and the KDO transferase genes of C. pneumoniae gave positive results for 6/10 preparations. We were unable to identify mRNA from the chlamydial major outer membrane protein gene (ompA) in any preparation. RNA preparations from the two control patients were negative in all RT-PCR assays targeting C. pneumoniae transcripts. These results indicate that in patients infected with the organism, synovial C. pneumoniae are viable and metabolically active, as are C. trachomatis cells in the same context. Such viability is consistent with a role in long-term contribution to pathogenesis in joint disease.

Sen M, Lauterbach K, El-Gabalawy H, Firestein GS, Corr M, Carson DA. · Department of Medicine and the Sam and Rose Stein Institute for Research on Aging, University of California, San Diego, La Jolla, CA 92093-0663, USA. · Proc Natl Acad Sci U S A. · Pubmed #10688908 links to  free full text

Abstract: Rheumatoid arthritis (RA) is accompanied by synovial inflammation, proliferation, and cartilage destruction. The reasons the activation of synovial fibroblasts often persists despite antiinflammatory therapy are not known. One possibility is that the synovial membrane becomes gradually repopulated with immature mesenchymal and bone marrow cells with altered properties. To explore this hypothesis, we have investigated the expression in RA synovial tissues of various embryonic growth factors from the wingless (wnt) and frizzled (fz) families, which have been implicated in cell-fate determination in both bone marrow progenitors and limb-bud mesenchyme. Reverse transcriptase-PCR analysis revealed expression of five wnt (wnt1, 5a, 10b, 11, and 13) and three fz (fz2, 5, and 7) isoforms in RA synovial tissues. Osteoarthritis synovial tissues expressed much less wnt5a and fz5. Northern blotting confirmed the overexpression of wnt5a and fz5 in RA synovial tissues, in comparison to a panel of normal adult tissues. Compared with normal synovial fibroblasts, cultured RA fibroblast-like synoviocytes expressed higher levels of IL-6, IL-8, and IL-15. Transfection of normal fibroblasts with a wnt5a expression vector reproduced this pattern of cytokine expression and stimulated IL-15 secretion. These results suggest that the unusual phenotypic properties of RA fibroblasts may be attributable partly to their replacement with primitive fibroblast-like synoviocytes with characteristics of immature bone marrow and mesenchymal cells. Clear delineation of the signaling pathway(s) initiated by the wnt5a/fz5 ligand-receptor pair in the RA synovium may yield new targets for therapeutic intervention.

Fang Q, Sun YY, El-Gabalawy H, Cai W, Ko L, Chin H, Arayssi T, Schumacher HR, Williams WV. · Department of Medicine, Rheumatology Division, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. · Pathobiology. · Pubmed #10023134 No free full text.

Abstract: Rheumatoid arthritis (RA) has been postulated to result from a synovial immune response to an unidentified antigen(s), which should be mirrored by the T cell response. Here we investigate the T cell receptor (TCR) repertoire in the synovial tissue of patients with arthritis of early to moderate duration. We developed a nested polymerase chain reaction (PCR) technique to examine the TCR repertoire of small biopsy specimens, and show that the method is highly sensitive. We apply this technique to synovial biopsies obtained from the knee joints of patients with early to moderate duration arthritis (average duration of arthritis 1 year, range 0. 02-2.75 years). We examined biopsies from 5 normal individuals, 32 RA patients, 7 patients with seronegative spondyloarthropathy (Sp), and 12 patients with undifferentiated arthritis (UA). TCR message was detectable in 4/5 normals, 15/32 RA, 5/7 Sp, and 8/11 UA biopsies, with sampling error likely accounting for most negative biopsies. The average numbers of TCR Vbetas detected per TCR-positive biopsy were 5.0 +/- 3.7 for normals, 12.7 +/- 8.4 for RA, 18.0 +/- 7.4 for Sp patients, and 14.4 +/- 10.2 for UA. Examination of TCR messages by single-stranded conformational polymorphism analysis showed similar proportions of dominant clones in the normals compared with the patients with inflammatory arthritis. Sequence analysis was performed on 33 dominant clones from 16 patients. Sequence alignment of the third hypervariable regions showed some evidence of disease-specific sequence clustering for Sp, while some RA sequences showed similarity to previously described motifs. These data indicate greater TCR heterogeneity in early Sp and UA compared with normal synovium. Disease-specific TCR sequences may occur in early RA and Sp.

Willemze A, Ioan-Facsinay A, El-Gabalawy H. · No affiliation provided · J Rheumatol. · Pubmed #19004060 links to  free full text

This publication has no abstract.